The Future of Science Revealed!

Well, one science journalist's opinion, anyway. Charles Seife writes for Science magazine and is the author of Alpha and Omega: The Search for the Beginning and End of the Universe. These are his answers to your questions, and they're very detailed, to the point where you may want to set aside more than a few minutes of quiet time to read and digest them. Q1) "Publishing hype" by BobTheLawyer (#6606631)

A1)I'm not embarrassed at all because it's not hype. Scientists now know how the universe will end. Of course, as with all things scientific, there's a big honking asterisk on the word "know," but before I get to that, let me explain why I feel justified in making such an arrogant statement.

We're in the middle of a scientific revolution, in the honest-to-god paradigm-shift sense. This revolution started in 1997 when two groups of astronomers, the High-Z Supernova Search Team and the Supernova Cosmology Project used the bright flashes of a particular type of dying star (a type-Ia supernova) to measure the expansion of the universe at different times in the past. Since then, a whole raft of astronomical observations -- of faint patterns in the afterglow of the big bang, of distributions of galaxies, of the composition of intergalactic clouds of gas, of distortions of light going around massive bodies -- have all forced cosmologists into a remarkable consensus about the composition of the universe and, yes, its fate.

Just to give you a little taste of what the difference in the state of knowledge was like: in 1997, if you asked an astronomer how old the universe is, you'd get an answer somewhere between 12 and 15 billion years. Now, you'll get an answer of 13.7 billion years, plus or minus about 100 million. That's a big jump in precision. Similarly, before 1997, nobody had a clue how the universe would end; now, cosmologists agree on its fate. Some of the details haven't been worked out (what an understatement!), but the gross picture of the ultimate fate of the cosmos seems to be pretty well established for the first time in history. And by the end of the decade, a lot of the details will be fleshed out.

The ongoing revolution isn't just astronomical; it's physical. A decade ago, nobody knew whether neutrinos have mass. (For those who aren't particle physicists, neutrinos are particles that so rarely interact with matter that they can easily pass through the Earth without noticing the big chunk of mass they've passed through. This property makes them exceedingly hard to study.) Now, neutrino physicists are in accord -- and they've concluded that neutrinos, collectively, weigh about as much as all the visible stars and galaxies in the universe combined. High-energy physicists are using an accelerator in Long Island to recreate the condition of the universe a few microseconds after the big bang. By next year, they will formally announce the creation of a new state of matter that existed only in the very, very early universe. (There are alreadystrong hints that they've succeeded.) And another particle accelerator under construction in Geneva is very likely going to discover the particle responsible for exotic dark matter. (More on this shortly.)

All these experiments, all these observations, are pointing in exactly the same direction; they reveal the composition of the universe and its fate. But as with any good scientific revolution, such as relativity or quantum mechanics, it generates more questions than it answers. Scientists now know how the universe will end, but that understanding comes at the cost of a new mystery in physics.

As to the asterisk on the word "know," scientists are acutely aware that their theories are subject to revision. But at the same time, they have good reasons for being confident about their theories -- and they are more confident about some theories than about others. The new cosmological picture that's emerged has a darn high confidence rating; extraordinary claims require extraordinary proof, and the scientific world wouldn't accept the ideas of dark matter, much less dark energy, if there weren't a number of independent lines of evidence that forced scientists to make that conclusion. And while they're not confident about many of the details of the cosmos and the mechanisms that shape it, they are pretty sure that the overall picture is correct. (More on this coming, too.)

Q2) [Almost] Serious question! by Noryungi (#6606694)

and

Q3) Why does the rate of expansion change? by Anonymous Coward (#6606745)

A2,3) The universe will end in... umm... you really want me to give away the ending to my book?

Actually, I reveal the answer in chapter four, because the understanding of the fate of the universe is just the beginning of the current cosmological revolution. So it's not a spoiler to say...

-- drum roll -- the universe will die a heat death, or "Dark & Cold" by your terminology.

In a big bang universe governed by the laws of general relativity, there are two possibilities. (Actually, there are more than two, but all the cases boil down to two real outcomes.) Big crunch or heat death, fire or ice.

The fate of the universe depends on how the universe expands. In general, things that expand cool down and things that are compressed heat up. (This is what causes a propane container to feel so cold after a barbecue -- all the gas that expanded.) After the big bang the universe was extremely hot and was seething with energy. As it expanded, it cooled; free-roaming quarks condensed into protons and neutrons, and wound up as hydrogen, helium, and a handful of other light elements and isotopes. About 400,000 years after the big bang, the universe cooled enough so that the electrons could combine with the nuclei and form neutral atoms. Now, about 14 billion years later, the universe is a pretty cool place.

The expansion of the universe is like a cannonball shot into the air. As the cannonball flies ever higher, the force of gravity tries to drag it back to earth, reducing its upward velocity and slowing it down as it zooms upward. If gravity is very strong, then the cannonball rapidly loses its speed and quickly comes crashing back to the ground. On the other hand, if gravity is very weak, then the cannonball might escape the pull of the earth entirely and zoom away into outer space.

Similarly, the big bang gave the universe an initial cannonshot of expansion. If the mutual gravitational attraction of the objects in the universe is very strong (if there's a lot of matter in the universe) the expansion will slow down, halt, and eventually reverse itself. After the cooling phase of expansion, the universe will begin to swallow itself, getting smaller and smaller each day. This will make it heat up. The skies will get brighter and brighter as galaxies and stars get closer and closer together, and eventually, the universe will become a bath of radiation once more. Electrons will separate from atoms, atoms and then protons and neutrons will shiver into their components, and the universe will collapse in a "big crunch," a reverse big bang. The cosmos will die a death by fire.

On the other hand, if there's not much matter in the universe, then the expansion of the universe will continue forever. The expansion will slow down, but it will never halt and never reverse itself. The universe continues to cool down, and for a long time, space will look pretty much as it does now. Stars will be born and die, and galaxies will age. The night sky would get darker and darker as distant objects get too dim to view, and eventually, as the hydrogen in the universe is consumed, stars and galaxies will begin to wink out. Many billions of years hence, the universe will be a lifeless soup of dim light and dead matter. It will be a death by ice.

In 1997 and 1998, the two supernova teams used the brightness of distant supernovae to measure the rate of expansion at different times in the past. (Because the speed of light is finite, looking into the distance is the same as looking into the past. This causes no end of tense problems when writing a book about cosmology.) What they found was absolutely gobsmacking. Not only was the universe's expansion not slowing down very much -- it was speeding up! The cannonball was zooming into the air faster and faster as if it were propelled by some sort of weird antigravity force. Not only was the cannonball going to escape, it is so OUTTA HERE! This means a death by ice.

Yegads -- an antigravity force. This was a really hard thing for scientists (and probably you) to accept. But there's a number of different lines of evidence that support the idea, and in the book I go through those lines of evidence in great detail. I'll have to settle for a brief summary here. In 2000, a balloon experiment known as Boomerang took very detailed pictures of the ubiquitous afterglow of the big bang, the cosmic microwave background (CMB). This afterglow has hot and cold spots in it, and for years, scientists have been making very, very detailed predictions about the size and distribution of those spots. The results of the Boomerang experiment and the DASI and WMAP experiments matched those predictions incredibly well, giving scientists great confidence in the underlying theory. It also allowed them to figure out the amount of matter and energy in the universe, and 73% of the "stuff" in the cosmos was dark energy, this antigravity force.

There are a number of other lines of evidence, too; the current distribution of galaxies, for example, implies the presence of an antigravity force, and just last month, scientists made a very nice measurement of something known as the late integrated Sachs-Wolfe effect. This effect can't occur unless you have something like dark energy counteracting gravity's pull.

Unfortunately, a fuller exposition requires a lot more writing -- it takes up several chapters in my book. (Shameless plug). But in summary, there's a number of independent observations that all point to the existence of a dark energy. Furthermore, the theories underlying the idea have made very specific predictions that have been verified with incredible precision. It's extraordinary stuff, but no matter how scientists look at it, they're forced by extraordinary evidence to make the same conclusion.

Yes, it's true that scientists don't know the mechanism of dark energy (though they're not entirely at sea) but there's little doubt that the cannonball is zooming into space faster and faster. They don't know precisely why, but the universe is being pushed toward its icy death by an antigravity force. Scientists are watching it happen.

And you don't need to wait billions of years to know the outcome -- you don't need to observe something directly to conclude that it's going to happen. The planet Pluto was discovered in 1930. So why don't people object to the statement that it takes about 250 years to complete an orbit? Just as you don't have to wait until 2180 to confirm the conclusions of Newtonian dynamics, you don't need to witness the end of the universe to be able to figure out its fate or validate the theory that leads you to that prediction.

Q4) Dark Matter by notcreative (#6606772)

A4) You are correct; the nature and location of dark matter are crucial puzzles in modern cosmology, but I think that the answers will be pretty much in hand by the end of the decade.

I've already mentioned results (most notably WMAP) that reveal the amount of "stuff" in the universe, and 73% of it is dark energy. The rest is matter. But the grand total of the matter locked up in visible stars is a mere 0.5% of the stuff in the universe. What is the other 26.5%? That's dark matter, and, in fact, there are two different types.

Scientists have known for decades that most of the matter in the universe is invisible to telescopes. In the 1960s, Vera Rubin measured the motion of stars wheeling around the center of the Andromeda galaxy and concluded that there had to be a lot more matter pulling on those stars than could be seen.

Despite what some contrarians say, dark matter isn't dogma; viable alternatives, like Moti Milgrom's MOND are taken seriously, if not accepted. Unfortunately, all of the alternatives, including MOND, fail in crucial ways. Besides, you can see dark matter, both directly and indirectly. The MACHO and OGLE projects see the twinkle of stars caused by a passing chunk of dark matter, and they can see the distortion of light caused by a huge amount of unseen mass sitting on the fabric of spacetime. (Distant galaxies are stretched into arcs around this gravitational lens.) This is allowing scientists to figure out just where dark matter resides. But at the same time, a number of observations lead scientists to conclude that the minority of the matter (dark or light) in the universe is ordinary, atomic matter -- the stuff of stars, planets, and people. Again, it will take too long to describe all the lines of evidence, but one powerful way of measuring the number of atoms in the universe is to look at the proportion of hydrogen to deuterium, helium, and lithium in primordial gas clouds. In the first three minutes of the universe, atoms were fusing, just as they do in a hydrogen bomb. The universe was a giant pressure cooker, turning protons and neutrons into heavier elements. If there are a lot of atoms, then there is a lot of fusion and a lot of heavy elements made; if there are not very many atoms, then the universe winds up being almost entirely hydrogen. By looking at the ratios of heavy elements to light elements, scientists concluded that atomic matter makes up about 4% of the "stuff" in the universe -- which is precisely what other measurements, like the CMB ones -- imply, too.

So, 27% of the stuff in the universe is matter: 4% "atomic" matter, leaving 23% to be made of "exotic" matter, stuff that's not made of atoms. I've already described some of that exotic matter; neutrinos make up about 0.5% of the stuff in the universe, about the same as the visible matter in the universe. What's the remainder?

That's the big open question, but one that I'd wager will be solved by the end of the decade. There are very good reasons -- particle physics ones, rather than cosmological ones -- for believing that the main constituent of dark matter is a proposed particle known as the LSP. If it is, then the LHC accelerator in Geneva will find it. If not, then the LSP almost certainly doesn't exist and the puzzle will be compounded -- but I think that scientists are extremely optimistic. Again, there's lots more detail in the book about the justification for this.

Q5) variable constants by Cally (#6607000)

A5) The point's well taken, and I'll get to it after a few remarks.

First, you're right in that the supernovae serve much the same purpose as Cepheid variable stars do -- they're both objects of known brightness, or "standard candles," that allow astronomers to make a precise measurement of the distance to a faraway galaxy. However, they are not the same thing. Cepheids are stars that pulsate and the rate of that pulsation reveals its intrinsic brightness. They're what Hubble used to spot the expansion of the universe in the 1920s, but they're relatively dim and impossible to find in very distant galaxies. Type-Ia supernovae are standard candles that are much, much brighter than Cepheids, and so can be seen halfway across the universe. (And as you note, since distant supernovae mean ancient supernovae, they reveal the expansion rate of the universe billions of years ago.)

Second, the time-varying speed of light (or more precisely, the time-varying fine structure constant) is a controversial idea. The scientists that made the observation in question are pretty solid and they're taken seriously. However, my impression is that mainstream thinking is that the results are due to a systematic error. That aside, the effect, even if real, is very small, and it has nothing to do with interpreting the data from standard candles. The interpretation there is quite well established; there's little question that scientists are seeing an expansion of the universe;. Alternative theories, like tired light, fail in countless ways and scientists have even seen the relativistic time dilation caused by the motion of the distant object.

But, yes, it's natural for a layperson to conclude that the concordance cosmological model is looking increasingly kludge-y, and you're naturally led to wonder whether scientists are trying to prop up a failing model with the equivalent of epicycles or aether. I don't think this is the case for a few reasons.

For one thing, the theory isn't really getting added to and made more complex; it's getting subtracted from and being made more simple. This seems counterintuitive, but it comes from the fact that modern big bang theory is really a class of theories, rather than one set-in-stone dictum about the way the universe is. All these theories agree on the basic physics about the manner of the universe's birth, the forces that drive the universe, and the physics behind them; the difference between the theories are the values of a handful of parameters that are not predicted by the theory. These parameters are inputs rather than outputs, and by pinning down the values of these inputs, the acceptable class of theories gets narrower and narrower.

Dark energy is one of these inputs. Although nobody took it seriously before 1998 -- everyone thought that the value of the parameter in question was zero -- it was lurking there nonetheless. It turns out that this parameter is not only non-zero, it's really big, much to everyone's surprise. But this doesn't add complexity to the model, especially since other parameters, such as the "curvature" of the universe as a whole, which many physicists thought would be non-trivial, turn out not to be important after all. (In other words, the universe seems to be slate flat, rather than saddle-shaped or sphere-like.)

So, from a mathematical viewpoint, the model is no more complex than it was in 1997, and is, in fact, significantly leaner. But what about from a physical viewpoint? Dark matter and dark energy seem to fly in the face of Occam. But here, too, the increase in complexity is much less than it appears. Long before this cosmological revolution, astronomers knew that dark matter had to exist; more recently, they've begun to see it. Even without worrying about cosmological questions, astrophysicists had accepted the existence of dark matter. Cosmological measurements like WMAP showed that these astrophysicists were right -- it was an independent confirmation that dark energy exists and that it comes in two forms, something that other astronomers had concluded a while ago.

Dark energy, on the other hand, has more claim to being a "hack" to the theory. It really is something new and unexpected (even though it was always a mathematical possibility, nobody in the physics world suspected it actually existed.) Nevertheless, the groundwork was already there, and modern big bang theory implicitly requires the existence of a form of dark energy in the very early universe. And since the 1930s, scientists knew that even the deepest vacuum is full of energy and can exert pressure (something known as the Casimir effect, which I describe in this book and in my previous book, Zero: The Biography of a Dangerous Idea). Thus, the idea of dark energy wasn't completely alien to physics before 1997, and in some sense, it was a necessary component.

Yes, it's possible that scientists are looking at the cosmos in the wrong way, and somebody will establish a simpler, more elegant theory that takes all these threads and weaves them together. (More on this shortly.) But at the moment, far from having a kludged-up theory, cosmologists have a leaner (if weirder) theory than ever before -- one that makes very precise predictions that are getting verified with stunning accuracy. I think this argues for increased confidence in the theory rather than for increased fear that it's falling apart.

Q6) Universe's container by bios10h (#6606748)

A6) It freaks a lot of people out. There's a lot of philosophical problems with having an infinite universe -- for example, if the universe is truly infinite, and if, as scientists believe, the number of quantum states of a finite volume is finite, then it's hard to escape the conclusion that, some great distance away, there's a bizarro-you on bizarro-earth reading bizarro-Slashdot. On the other hand, there's no positive evidence that I can think of that the universe is truly infinite; it's just the sparest conclusion in a mathematical sense, if not a philosophical sense.

But an infinite universe is not a foregone conclusion. Earlier this year, Max Tegmark at the University of Pennsylvania published an intriguing paper that looked at slight anomalies in the WMAP data that seem to imply that the universe is not only finite, but shaped like a donut. Nobody takes the idea terribly seriously, not even the author, because there are other statistical tests that seem to rule the donut-shaped universe out. But it's the sort of thing that people are looking at very closely.

Whether it's finite or infinite, in a mathematical sense, there's really no need for the universe to be "in" anything -- there are models where our universe is embedded in a higher-dimensional space, but there are models where it isn't. Philosophically, though, I don't see any advantage to embedding the universe in something bigger -- as you say, it just punts the problem forward. (Who, then, will contain the containers?)

It's one of those things that is hard to get comfortable with -- and even when you accept it, it sometimes can cause pangs of uncertainty. Quantum mechanics does this, too... it's just something that's hard to wrap your head around. Take solace in the fact that it's hard for everyone else, too.

Q7) How ultimate is the end of the universe? by Lane.exe (#6606766)

A7) If there were a collapse-type universe, yes, there could be a reboot and a new big bang. (And if Microsoft built the universe, a reboot would be coming sooner rather than later. *duck*)

In fact, the theory behind the cosmic microwave background stemmed from calculations to see whether this was possible. Remember the expansion-cooling/contraction-heating bit I mentioned a while ago? A physicist at Princeton was trying to figure out whether matter would break apart into its constituents in a collapsing universe, so he looked at how the universe heated up as it compressed. He then realized that his calculations worked equally well in reverse -- the young expanding universe was very hot but cooling -- and it had to have an afterglow: the CMB.

There are restrictions on this rebirth argument, though. For one thing, the fact that the universe will expand forever prevents a big crunch in our future, so we're at the end of the line if such a line existed. And in 2001, Alan Guth proved a mathematical theorem that shows that bang/crunch/bang universes can't have an infinite history; they must have started some finite time in the past. (Though there are a few ways around the theorem if you reject a few assumptions.) So yes, it's possible, but there is no reason to believe it actually happened, and there are very good reasons for thinking it won't happen in the future.

Q8) comparable ramifications? by sstory (#6606658)

A8) I'm not going to give the usual B.S. answers about spinoffs (though there are some). And I'm not going to evade the question by saying that genomics hasn't yielded any transformation, because the potential is certainly there. But I will answer this question obliquely.

If I asked you, "Quick! What's the most important scientific achievement of the 20th century?" how would you respond?

You would probably answer relativity or quantum mechanics, or perhaps the Apollo landings. Probably some would say the atom bomb. I suspect that only a handful of people would mention the computer, and even fewer people would say penicillin. (Am I right?)

Science has two faces -- it can transform society (for better or worse), and it can advance human knowledge. The two are not inextricably bound, though they often come together.

Relativity was a profound shift in our understanding of the way the universe works, but you have to look pretty hard to see a direct effect on our lives. Conversely, penicillin wasn't a central advance in understanding biological systems, but it affected all of us -- I suspect many people here on Slashdot wouldn't be alive today without penicillin and its descendants.

For me, though, relativity is a greater scientific triumph than penicillin -- even though penicillin is probably much more important to us. It altered our view of the universe and gave us a greater understanding of the fundamental laws of the universe -- it was a philosophical advance as much as it was a technical one. That's why we seem to admire Einstein more than Fleming and Newton more than Jenner.

The present cosmological revolution won't change our lives dramatically; heck, a good spam filter would probably have more direct effect on our quality of life. But at the same time, it will finally answer some of the most ancient questions of humanity -- where did the universe come from and how will it end -- and when it ends, we will have a firm grasp of the answer of the latter if not the former. It will be a towering intellectual achievement, and I think that is what will set it apart from even the human genome project.

Q9) What is the next paradigm shift? by geeber (#6606890)

A9) I disagree with the idea that there's no paradigm shifts left -- indeed, I think we're in the middle of one now. I think that it will be associated with one in the Standard Model of particle physics that will begin before the end of the decade.

It's hard to say where future paradigm shifts lie, but there are lots and lots of outstanding questions in science, some of which are incredibly basic, yet totally out of scientists' reach. For example, neurologists have a very good idea about how individual neurons work -- how they connect and communicate. But when it comes to explaining how a large sloppy hunk of neurons becomes a conscious entity, they're completely at sea. I don't think there's even a good definition of consciousness, which is crucial if you're going to study it seriously. Even more basic -- scientists are struggling to define what life is. There's a heck of a lot more work to do, and plenty of room for paradigm shifts.

Speaking of paradigm shifts, I'd like to take a bit of issue with the term (which I've used myself a number of times in the responses to these questions.)

For those who don't know, the idea of a "paradigm shift" comes from Thomas Kuhn's Structure of Scientific Revolutions, a seminal work in history of science. While I think that Kuhn's idea of a paradigm shift has a lot of merit -- models and philosophies do change suddenly and dramatically in the face of mounting conflicting evidence and despite resistance -- I think the term itself is misleading. It implies the complete abandonment of one idea and acceptance of a replacement.

In my view, this is not the way modern science works -- I think that science is cumulative. Each model extends and corrects the previous one, and while there might be a dramatic shift philosophically, there is almost never a dramatic shift physically. Relativity, for example, made a profound change in the way we think about time and space and gravity, yet the functional difference between Newton and Einstein is pretty small. All these complicated tensor equations are approximately equal to Newton's laws in the vast, vast majority of cases -- it's only under conditions of extreme gravity, extreme speed, extreme energy, or extreme time that relativistic predictions diverge from Newton's. Similarly with quantum mechanics.

While I think that relativity and quantum mechanics are paradigm shifts, they're not rejections of the Newtonian picture as much as they are extensions. The paradigm shift can be huge philosophically, but its effects tend to be small in magnitude. And with these small corrections, scientists extend the applicability of their model of the universe -- they can explain the orbit of Mercury or the photoelectric effect -- and in the cases where Newton's laws were strong, these models boil down to Newton's laws.

If I remember my Kuhn correctly, he explicitly rejected the idea of cumulative science; he really saw each model getting completely replaced by its successor, rather than as an extension -- and this leads, at least in my view, to the excesses of postmodernism.

I think that this issue goes to the heart of the questions about how scientists can be sure about the end of the universe if their models can be replaced at any time. To that I'd argue that, yes, all models are provisional, but even with "paradigm shifts" models are usually extended rather than replaced. The central findings of the previous model still hold with good accuracy in most cases, even if the philosophical underpinnings are badly shaken. Maybe scientists are missing some crucial understanding that will simplify the way we look at the universe -- and scientists are seriously pondering alternate models to things as widely accepted as the inflationary big bang -- but even if such a shift occurs, it probably won't invalidate today's discoveries.

Q10) What will it mean? by boatboy (#6607285)

A10) One thing's certain. If I knew the answers, I'd be even more insufferable than I am now.

Seriously, I'm not sure that knowing the answers would have a profound moral and sociological effect. While I think that asking and answering big questions is a hallmark of a prospering society, a society doesn't necessarily draw strength or stability from its intellectual curiosity. (For example, Athenian democracy lasted only about 80 years if I remember right.) Even the most profound philosophical ideas can wind up having little real effect on the everyday functioning of a civilization -- for example, I think that Godel's incompleteness theorem hasn't changed society in the slightest.

As for the next big question, I think there are some in biology: what is life? What is consciousness? How did life arise? Are we alone in the universe? In physics, I think there are profound questions yet to be answered in a realm that I'd describe as "information theory" in the broadest sense -- what's really going on in a black hole? What makes quantum mechanics so weird? And I think that answering the question about the true nature of dark energy will probably have to await a future cosmological revolution. But one of the wonderful things about science is that you don't really know what big questions are within your grasp until you begin to grasp them. We'll know the next revolution when it appears.

Editor's note: Due to long answer lengths, we linked to the questions instead of running them directly here in order to keep this page from getting too large. This was an experiment. If you have comments or questions about Slashdot interview formatting, please email Roblimo.

Comments

The real question:

[Eric(b0mb)Dennis]

The year is 2125, a mars outpost is posting their first research on the inter-net-net using the tachyon stream to transmit their data.

A well known website known as Slashdot.org posts a link to the research papers, all of the sudden, the entire universe collapses because the tachyon stream was overloaded.

That is the end of the universe, all of humanity blinked out of existence.

Slashdot.org, a useful forum of information, or the end of the world waiting to happen? You decide.

Re:The real question:

[IFF123]

What's at the end of the universe: blue screen.
the guy also believe so, based on one of his answers :)

Re:The real question:

[KillerHamster]

Slashdot.org, a useful forum of information, or the end of the world waiting to happen?

Well, I think we can safely rule out one of those options...

Re:The real question:

[ae0nflx]

Jez. I'm so tired of all this 'universe collapsing' stuff. In 2125, we'll just need to thaw out Wil Wheaton and have him reverse the polarity of the tachyon stream. Then everything will be fine...

Re:The real question:

[Anonymous Coward]

Slashdot, the end of all productivity and the bane of PHBs everywhere! ;^)

Re:The real question:

[Luigi30]

Don't you know? There's a restaurant at the end of the universe.

Re:The real question:

[Directrix1]

OK, so the proof that we are going to die a heat death is in the evidence of outward acceleration. Now do we definetely know that this object is accelerating radially outward or radially inward to another distant unknown universe. I.e. how can we claim to know the extents of the universe, if we don't have infinetely sensitive equipment. It could be we're on course to collide with a system (another known universe sized structure) like ours that is so distant we just can't see it yet. Maybe there are infinite systems like this out there. How can we possibly claim to know this?

Re:The real question:

[Anonymous Coward]

Please dont talk about tachyons. They break causality and you probably dont know the issues with such fact.

Re:The real question:

[Anonymous Coward]

Be nice to Wil, he might respond.

Re:Wait A Minute..

[ihummel]

What do you expect from a /. Q&A segment about the future of anything. The future is undecided.

Re:Wait A Minute..

[Matt_Fisher]

haha very true.. you learn fast grasshopper

Cold & Dark, eh?

[TopShelf]

So when can I cut back on the air conditioning???

Obligatory Simpsons Quote

[magsymp]

donut-shaped universe mmmmmmmmm.... donut.

Re:Obligatory Simpsons Quote

[Anonymous Coward]

If you're going to do that, at least get it right.

Re:Obligatory Simpsons Quote

[foniksonik]

There is a 'song' based on that episode or cumulation of episodes by Aphex Twin... hilarious... donut, donut, donut.... all I want is a donut.

Re:What are we playing jeapordy now?

[Matt_Fisher]

I bet he is old :)

Questions?

[efflux]

What happened to the questions? These links to the actual questions are a pain to read. More than subject headings would have been nice

Re:Questions?

[Anonymous Coward]

Right-click > Open in New Window

Re:Questions?

[Anonymous Coward]

Your subscription dollars at work! You pay and you do the work!

Re:Questions?

[FroMan]

Middle click, and it loads a new tab.

Re:Questions?

[Anonymous Coward]

Not in Opera... Oh, I guess you mean Mozilla.

Re:Questions?

[FroMan]

I don't know about opera, my wife uses it though.

In mozilla you can set new tab to ctrl-click or middle click. there might be more options, but I am too lazy to go the the prefences...

Re:Questions?

[Bananenrepublik]

Two words: tabbed browsing.

Re:Questions?

[MegaFur]

I liked it. :-P Anyway, they give you an address to send your complaints to:
robin@roblimo.nospam.com | grep -v "nospam."

Re:Questions?

[an_mo]

5 words:
That does not help much

Re:Questions?

[breadbot]

I kind of liked it. I could guess each question pretty easily from its answer. It might not work well with all interviews, but with this one I think it helped the flow overall. It made it read like one long discourse, which it was, more than other interviews.

The effect would have been entirely different with William Shatner's infamous interview ...

Of course, I don't hear the bad reviews or see them. All I know is the glowing notices that people read to me that some reviewer thinks I'm wonderful. So I've slowly come to think that I'm wonderful.

I think John Belushi probably did the best.

I think the whole interracial kiss thing has been overrated. Nichelle Nichols was a beautiful woman and her lips were full. I merely sought to make an impression.

Ok, I'll be honest. It was a laugh. Pure & simple. You should have at least been mildly amused. It seems to me that you need to get a life.

Actually, I don't think that actors think much about MPAA. They're more concerned about AARP.

Yes, I enjoyed it. I think Tim Allen was very funny. As for accuracy, not at all.

Oh Contrare. That's French, in case you need it, for 'to the contrary.' I had a great time at McGill. I did go to a ceremony at the student union building and my feeling about McGill is that it's a great university and it produced many great students. Unfortunately, I was not one of them.

Thank you for asking about Nerine's fund. It benefits a rehabilitation place called Friendly House. They do wonderful work. Nerine has a rehabilitation home with her name on it and my hope and sympathy is for these recovering women.

Dear Will,
We are so cool, we're beyond cool. We are in orbit man. I don't do pre-game strategy.
I look forward to some personal time with you.

Regret is the worst of human emotions. There is no going back with regret. There is no future with regret. Regret is not something I live with. If there is something I wished I hadn't done, I don't do it anymore or I forgive myself and try better.
My life is my statement and I try to be true to myself and thusly to other people. Whatever my failings are, they are human and I try to perfect it each day.

Actually, you know what? I think I like that one better the new way too!

A7

[roman_mir]

If there were a collapse-type universe, yes, there could be a reboot and a new big bang. (And if Microsoft built the universe, a reboot would be coming sooner rather than later. *duck*) - this is /. You don't have to *duck*!

Re:A7

[misterhaan]

universe: reloaded

Re:A7

[LadyLucky]

The universe is being restarted. Please save your work.

Re:A7

[whereiswaldo]

The universe is being restarted. Please save your work.

The universe has performed an illegal operation and will be shut down.

It is now safe to turn off your universe.

hm

[EMH_Mark3]

Any reason why the questions weren't transcribed as with other Ask Slashdots?

Re:hm

[kisrael]

What's wrong with a bit of metaconversation on slashdot?

Anyway, the formatting's pretty useless. Compared to the size of the answers and the comments, the questions are really small potatoes, and making them links instead of embedding them is just distracting.

Re:hm

[EMH_Mark3]

Ah. Well.. er it's silly to put that at the bottom! *ahem*

Re:hm

[EMH_Mark3]

Dare I put forth a selling-as-much-ad-impressions-as-possible conspiracy theory? :)

Re:hm

[Thing 1]

obConspiracy: perhaps they're going for more ad impressions?

I agree, it's ridiculous to make the questions links. Please don't do it again, guys.

if we find ...

[i.r.id10t]

If we find the "end of the universe", will there be a resturant, perhaps with a evening show?

Re:if we find ...

[corgicorgi]

If we find the "end of the universe", will there be a resturant, perhaps with a evening show?

And dine on a creature that wants to be eaten.

Re:What are we playing jeapordy now?

[magsymp]

Test format for the Interview articles.

It was too long to include the questions, so the Slashdot staff tried this new format.

Editor's note: Due to long answer lengths, we linked to the questions instead of running them directly here in order to keep this page from getting too large. This was an experiment. If you have comments or questions about Slashdot interview formatting, please email Roblimo.

Not so Anonymous Coward

[dlosey]

Take a look at Q3. Is that an Anonymous Coward post in which the User ID accidentally got slipped in?

OOPS!

Re:Not so Anonymous Coward

[dlosey]

Shhh!

Yes I know those are not UIDs, but lets see who wont read this reply before posting.

Re:Not so Anonymous Coward

[kleine18]

nope. look again.

Re:Not so Anonymous Coward

[jericho4.0]

No. That's a link to the comment.

Excellent interview

[Timmeh]

This is easily on of the best interviews I've seen on slashdot in a long time. Kudos to Charles Seife for writing extensively instead of sort of brushing us off with the brusque answers usually found in the interview section. It feels like if the person being interviewed isn't into the whole 'technology'/slashdot/nerd thing they look down on us and humor us with their answers instead of writing interesting replies.

Re:Excellent interview

[Anonymous Coward]

Well, astronomy is sort of a nerdy subject...

Re:Excellent interview

[Mostly Harmless]

I agree, this interview is outstanding. I like this the best, something that you don't hear too often:

One thing's certain. If I knew the answers, I'd be even more insufferable than I am now.

Not only does he acknowledge that he wrote a bunch, but he knows that he doesn't know everything. That's refreshing around here. He admits that things change, and what he says isn't the be-all-end-all of ideas. But, perhaps, the most refreshing thing in the interview is that he didn't answer a single question with "42." Now that's something new!

Re:Excellent interview

[Timmeh]

True, but it's like the geek hierarchy, as far as serious astronomers and authors are concerned, we slashdot posters aren't but a few evolutionary steps from the furries. :P

Re:Excellent interview

[Anonymous Coward]

Well, some Slashdot posters are actually practicing astronomers and authors ...

Re:Excellent interview

[teece]

I agree wholeheartedly.

I recently got laid off, and deciced to go back to school and finish my degree. In a painful bit of decision making, I decided I would turn my Computer Science work into a minor, and Major in Phyisics (which was my first choice, long ago, but I wimped out). It is stuff like this that makes me happy I did.

A really great Ask Slashdot. I will be buying Mr. Seife's book. It's the least I can do to reward the very nice effort that went into these insightful answers.

Re:Excellent interview

[psavo]

This is easily on of the best interviews I've seen on slashdot in a long time.

Yeah, so true. And all thanks to me.

Why? - you may ask. Well. Because every time I'm on a brink to delete /. from my bookmarks, history and CTRL-H keybind (yeah, I'm pathetic), they manage to pull stuff like this.

Great many thanks to Charles for this!

Re:Excellent interview

[Anonymous Coward]

Yeah ok you guys win :p

Re:Excellent interview

[Anonymous Coward]

pseudo-mod: +1 Funny

Re:Excellent interview

[whereiswaldo]

I agree, this interview is outstanding.

Now if a regular user like I was going to write a huge interview like that, I would be sorely disappointed if the review were rejected. What's the motivation for me to go out and try to produce something so lengthy and in-depth?

Not only does he acknowledge that he wrote a bunch, but he knows that he doesn't know everything.

I like the part where he mentioned the huge asterisk when scientists say they "know" something. It always bothers me when people say scientists "know" things. That's obviously not true, in most cases. They only believe it to be true and have a finite set of cases which seem to agree. We as a human race redefine what we know every day.

REALITY.SYS

[kleine18]

REALITY.SYS corrupted: Re-boot universe? (Y/N).

Re:REALITY.SYS

[blitzoid]

I'd like to take a look at that file.

Re:REALITY.SYS

[EvilTwinSkippy]

In the universe simulation sector of Morgan Industries we have an error message that often pops up during testing, asking whether to Abort, Retry, or Ignore. The programmers are instructed to NEVER select abort.

Re:REALITY.SYS

[hak hak]

Press OK to terminate universe.
Press Cancel to debug.
[ ] Send bug report.

Re:REALITY.SYS

[Anonymous Coward]

you haven't been around much. reality is clearly an API.

What answers ?

[Timesprout]

The only answer I see is that the universe will eventually implode on itself but I thought with the dicovery of background radiation we had decided this was not going to happen and as improbable as it sounds the universe would expand infinitely.

Re:What answers ?

[Anonymous Coward]

The only answer I see is that the universe will eventually implode on itself but I thought with the dicovery of background radiation we had decided this was not going to happen and as improbable as it sounds the universe would expand infinitely.

He didn't say the universe will implode on itself; he said what you said, that it will expand indefinitely. He mentioned the Big Crunch, but only as an unfavored alternative.

Re:What answers ?

[RatBastard]

Um, no. He said that the universe will expand forever and freeze to death. He stated that one of the theorized ends of the universe was the Big Crunch, but he said that it's been pretty well decided that the universe is not going that way.

Re:What answers ?

[IpalindromeI]

Did you even read the interview? Oh yes, this is /.

Almost every one of his answers about the end of the universe states that it's going to expand infinitely. Do a search for "-- drum roll --" on the story text and you can't miss it.

Re:What answers ?

[EvilTwinSkippy]

...I see is that the universe will eventually implode on itself ... improbable as it sounds the universe would expand infinitely ...

That's not the universe, that's threads on Slashdot.

Re:What answers ?

[toivoti11]

The universe will probably implode, since nothing is permanent. Expanding to infinity would be permanent, wouldn't it? So, there MUST be enough matter to invert the expansion of the universe. There really insn't need to invent any dark matter, just do the math more precisely. That's only my perception of the matter, what's yours?

Re:What answers ?

[toivoti11]

This infinite stuff freaks me out. All the well established phenomenon in the universe are cyclic. Why not this? The universe would be better off imploding on it self than expanding, since there always is the force of gravity that is more likely to do the universe in than anything else. I do not want to speculate with the dark matter since it sounds like the ether theory back in the 1800's. Are you familiar with this? The scientists came up with this ether, since they didn't believe anytihng would be transmitted in the void of space without the ether. That was before the invention of the radio.. Sigh... Why won't people learn from the past?

Re:What answers ?

[Anonymous Coward]

The universe will probably implode, since nothing is permanent. Expanding to infinity would be permanent, wouldn't it? So, there MUST be enough matter to invert the expansion of the universe.

There isn't any law of physics that says "nothing is permanent". That is merely a philosophical prejudice you have. The universe need not conform to your opinion.

There really insn't need to invent any dark matter, just do the math more precisely.

The math can be done more precisely than the actual data we have to plug into it. The need for dark matter doesn't have anything to do with the mathematical precision of our theories.

Re:What answers ?

[Anonymous Coward]

This infinite stuff freaks me out. All the well established phenomenon in the universe are cyclic.

Nonsense. Look around you. Practically everything is non-cyclic.

The universe would be better off imploding on it self than expanding, since there always is the force of gravity that is more likely to do the universe in than anything else.

"Better off"? What the heck does it mean for the universe to be "better off"? Anyway, whether gravity makes the universe recollapse or not depends on how fast it is expanding, and whether the force of gravity is attractive or repulsive at large distances. It is not a matter of opinion what you think the universe "would be better off doing"; the question is, what is it doing?

I do not want to speculate with the dark matter since it sounds like the ether theory back in the 1800's. Are you familiar with this? The scientists came up with this ether, since they didn't believe anytihng would be transmitted in the void of space without the ether. That was before the invention of the radio.. Sigh... Why won't people learn from the past?

Why don't you learn from the past? Dark matter is almost directly analogous to the discovery of Neptune. Uranus's orbit apparently wasn't obeying the laws of gravity. The options were (a) the laws of gravity were wrong, or (b) there was an unseen mass whose gravitational effects were perturbing the orbit. People could have sneered at (b) and derided it as you deride dark matter, but instead they chose to keep the laws of gravity and hypothesize an unseen mass. After patient observation, they finally found it: Neptune.

Bizaro Slashdot

[mike_mgo]

Considering the comments I read in most of the articles I thought I was on bizaro slashdot.

Re:Bizaro Slashdot

[Anonymous Coward]

But how would *you* know ?

Re:Bizaro Slashdot

[Anonymous Coward]

Simple: everybody has an evil goatee.

Re:Bizaro Slashdot

[EvilTwinSkippy]

Then I've been in Bizaro slashdot since high school...

Re:Bizaro Slashdot

[Pinball Wizard]

The spelling and punctuation in the stories would be correct, the first twenty comments would contain insightful dialog, and moderation scores would fit the posts they were attached to.

Re:What are we playing jeapordy now?

[stratjakt]

What kind of a idiotic idea is that, anyways? Yeah the questions arent important.

I guess not in an interview like this, which is just some windbag pontificating endlessly about nothing at all.

But still, what kind of idiotic interview doesnt show the questions being asked?

Q1: ?
A: Yes

Uhhh..

[cK-Gunslinger]

...you may want to set aside more than a few minutes of quiet time to read and digest them.

Why bother reading when you could be posting!! Woohoo!! Everybody look at me! Yah! :)

Huh?

[Austerity Empowers]

Why is Roblimo interviewing a journalist at a science magazine? Why not interview the scientists themselves?

I believe this guy is better than your average journalist at summarizing key ideas, but this is a website for nerds. Give us the real deal or give us more SCO stories.

Re:Huh?

[EvilTwinSkippy]

Read The Machine Stops by E. M. Forster. Written in 1909, it sure describes the Internet to a T.

Re:Huh?

[revividus]

If you check out the guy's website, you'll see he has a Master's Degree in Mathematics as well as Journalism. I know math is not the topic under discussion here, but a graduate degree in mathematics, coupled with his informative answers, is enough to earn a chunk of my respect.

Besides, we can easily summarize the next set of SCO stories:
- SCO sues everybody
- Everybody gives SCO the finger
Followed by,
- Everybody gives SCO the finger, in court.

Re:What are we playing jeapordy now?

[Anonymous Coward]

So far 1x -1 troll 2x -1, Off topic

Agreed.

[AltGrendel]

Please don't do that again.

Re:Agreed.

[Otter]

It appears to be a test of a new interview format -- here's another thumbs down.

This is a particularly bad interview to try it, also. Usually you can read the answer and make a good guess as to what the question was. ("How can we be sure you're not secretly working for a Microsoft/RIAA conspiracy to crush Linux?") But when an answer starts with "First, you're right in that the supernovae serve much the same purpose as Cepheid variable stars do -- they're both objects of known brightness, or "standard candles," that allow astronomers to make a precise measurement of the distance to a faraway galaxy." it would be nice to have the question at hand.

Anyway, Roblimo -- points for trying something new but please forget this plan.

Re:Agreed.

[Ryan Amos]

I second that. Or third it, as the case may be.

Re:Agreed.

[I am Jack's username]

> Please don't do that again.
> -- AltGrendel

Please don't do what again?

Dark Energy

[cybercuzco]

Heres a question: Since theres so much more dark energy than matter, would it be possible that some future descendants of humans could tap this energy to slow or stop the expansion rate of the universe, or even recreate galaxies using the energy? This might be a good sci-fi novel topic ;-)

Re:Dark Energy

[Anonymous Coward]

Look at Isaac Asimov's short story "The Last Question". The gist of the matter is that Entropy of the Universe is ever increasing.

Re:Dark Energy

[EvilTwinSkippy]

You are assuming that the Universe we are experiencing is not, in fact, a reflection of a deeper structure. Our perception of that structure at present is expanding, but at some point in time a controlling factor could take affect and reign everything back in.

I like to think of the Universe as an organism. It has a definite beginning event. The end, is not so clean cut.

Let's imagine our Universe is in fact a human being.

Now imaging you are a microcivilization who came into experience when the human was 4 years old. An entire civilization would wink in and out of existance by the time the Universe's heart beat once. If they tried to observe all of the molecules in the body, they would see a rapidly expanding organism, that seems to have at one time occupied a single point in space.

Despite the illusion, around puberty the Universe would stop growing.

Re:Dark Energy

[meta-monkey]

Mod parent up. Jesus that was a good story. The last sentence of the story floored me. I think I just sat there in stunned silence for 15 minutes after I finished it.

Re:Dark Energy

[renard]

Since theres so much more dark energy than matter, would it be possible that some future descendants of humans could tap this energy...

First answer: No. Dark energy is a property of the vacuum itself - being able to tap into it would be like extracting energy from a uniform, infinite heat bath (the vacuum), or from the zero-point energy of an atom's ground state, and would enable construction of perpetual motion machines and other impossibilities. That is, extraction of useful work from the "dark energy" is ruled out by basic thermodynamics (or, if you prefer, basic quantum - the same principles apply). However...

Second answer: Maybe. In general it is true that the universe and the systems in it tend naturally towards their ground states (increasing entropy). However, it is also true that thermodynamic fluctuations happen, every now and then, and the lifetime of these "defects" can be quite long - think, for example, of the conjectured cosmic strings. Now that we know the Dark Energy exists, we can guess that it might be possible - far, far in the future, when we are an intergalactic species - to find some defects in the system. We could then set up some apparatus, and extract energy from these defects as we watch (or encourage) their "decay" to the true ground state.

Stopping the expansion of the universe itself, however, will even then be well out of reach. Our best long-long-term bet, if you ask me, is to create our own new universe and go live there, once this one gets old...

-renard

Re:Dark Energy

[foniksonik]

Whatever happened to recycling? Everyone wants to have the shiny NEW thingamabob...

Re:Dark Energy

[Zaak]

Let's imagine our Universe is in fact a human being.

Now imaging you are a microcivilization who came into experience when the human was 4 years old. An entire civilization would wink in and out of existance by the time the Universe's heart beat once. If they tried to observe all of the molecules in the body, they would see a rapidly expanding organism, that seems to have at one time occupied a single point in space.

Despite the illusion, around puberty the Universe would stop growing.

That's an interesting idea. I see a flaw in your analogy though. It's true that a human's growth stops once reaching adulthood, but the adult will eventually die anyway.

Are you saying that the universe won't eventually die, or that its fate cannot be predicted by what we can see of the past?

TTFN

Re:Dark Energy

[EvilTwinSkippy]

Are you saying that the universe won't eventually die, or that its fate cannot be predicted by what we can see of the past?

Mostly that past performance is no predictor of future returns. We haven't even scratched the surface of what's out there. It's a little premature to say ANYTHING about the Universe with authority, considering that we still haven't solved a few basic problems of celestial mechanics.

For instance, the reports position of the Pioneer spacecraft is off from where all of our theories about relativity put it. Either there are other celestial bodies in our Solar System exerting influence, some of our understanding of the properties of existing bodies is incorrect, or we have to tweak relativity.

Now I would think that it would be a far more constructive use of computing time to flesh out our understanding of the Solar System around us. Some unknown here and now has a far greater chance of influencing life on Earth.

Re:Dark Energy

[Anonymous Coward]

...wouldnt it be ironic if the very cause of the expansion that we are seeing is a result of future civilizations creating new universes within the current one? this would lead to some interesting theories regarding time/space relationships. it would be possible for a future civilization to exist at the same time as a present civilization, only seperated by dimensions. i saw an article in popular science about how "close" another dimension might exist to our own, and if i remember correctly it was something like a hundredth of a centimeter or something...pretty wild.

The Last Question

[I8TheWorm]

Isaac Asimov already figured it out...

The Last Question

Re:The Last Question

[killmenow]

Thank you. I had never read that and found it was good.

Re:The Last Question

[It doesn't come easy]

A fascinating speculation concerning the progression of Man and the Universe. I enjoy Isaac Asimov. Ignoring the liberties taken with the concept of hyperspace (Is hyperspace part of the Universe? If so, it also would be subject to entropy. If not, what is it part of?), entropy will never go to maximum but it may get to a point where no useful work can be accomplished, regardless of efficiency. Truth is, the only true escape from the death of the Universe is to escape the Universe. However, the question then becomes: Does Man have the right? And the answer is: Only if Man is the only intelligent life in the All of Everything (we'll be prejudiced against unintelligent life for now). And this is unlikely. So, Man better learn to create (like the story concludes) or we're doomed.

As an aside, I wonder what the Universe is contained in?

Re:The Last Question

[danratherfan]

funny...

but it's the man without a past problem if the universe is created by something that can only be created by the creation of the universe, so it's impossible.

Please correct

[Viking Coder]

Editors, please correct the missing quote in the URL right after the first occurance of the phrase "MACHO".

Re:Wait A Minute..

[Anonymous Coward]

The Future is not set. There is no fate but what we make for ourselves!

man is the measure and like that

[Anonymous Coward]

Science is a social phenomenon. The spit of the moderns smeared upon the spit of the ancients- and the mound gets taller.
You say science is "true" becaue it "works"? Well that's what's known as a *long leap*.
Perceptual habits are to be gotten over, not embraced.
Science does not clarify.
At all.

Read the bottom of the article...

[eclectic4]

Editor's note: Due to long answer lengths, we linked to the questions instead of running them directly here in order to keep this page from getting too large. This was an experiment. If you have comments or questions about Slashdot interview formatting, please email Roblimo.

Re:Read the bottom of the article...

[kryten]

It would have been shorter if they'd just listed the questions and linked to the answers.

Or even shorter if they'd had links for both questions AND answers.

Or perhaps I've been playing too much perlgolf.

Stephen Hawking says:

[spun]

Your theory of a donut shaped universe is intriguing, Homer. I may have to steal it.

Re:Stephen Hawking says:

[FroMan]

The best part of a donut shaped world is that civilization maps make more sense. :-)

Re:Stephen Hawking says:

[VanillaCoke420]

But in Civ II you can't cross the poles, right?

Re:Stephen Hawking says:

[praedor]

He also said:
"Here's another $5. How about another lapdance?"

Re:Stephen Hawking says:

[spun]

Yes, and in some alternate universe, he said:

Dr. Dre can suck my dick,
that bitch got no PHD,
I lost count of mine,
I got stupid whack degrees.
Complex math it ain't no thing,
I'm mad dope crazy fly,
like Quantum formula,
I'll leave you asking why.

Among other mad-phat crazy lyrics to be found at MC Hawking's Crib

The Simulation Argument

[Anonymous Coward]

Hey, don't forget this "we're all living in a computer simulation" joke is actually a serious philosophical theory from Oxford's Nick Bostom (The Simulation Argument). Apparently, a lot of the numbers underlying our universe imply this world of ours really could be part of a computer program run by an advanced civilisation.

When our computers were first introduced, simulations were serious academic endeavours. Nowadays, fifty years later, most simulations of worlds are in computer games. Most computer games are run under Windows. So some future Microsoft probably really has built our universe's operating system.

Ooops.

Re:The Simulation Argument

[Anonymous Coward]

For a sci-fi take, read Permutation City by Greg Egan.

Re:The Simulation Argument

[RatBastard]

Serious theory if you are stuck in high school level philosophy. While it sounds cool and all, it's pointless unless you want to write a sci-fi book and dazzle thirteen-year olds. It, like the "life came from outer space" argument simply passes the buck to another layer but does not answer the question. If we exist in a simulation, where does the simulation reside? What universe contains the computer that we all live inside of?

Re:The Simulation Argument

[Anonymous Coward]

I find the simulation argument useful when I run into people who have some kind of philosophical objection to a particular aspect of physics. e.g., they insist that light must have a physical aether medium to travel through or something, and that it's impossible for light to travel through vacuum. If you accept the simulation argument, then must accept that a universe could obey any simulable set of laws; therefore, if it's possible to write down laws feature light propagating without an aether, then it's possible for such a universe to exist.

Re:The Simulation Argument

[harborpirate]

Exactly. The problem is that the theory is impossible to disprove.

I see that the topic of at least one of the linked papers contains the idea that it might be possible to prove the simulation theory, which is mildy interesting. I think ultimately however, even that is pointless.

Since we do not understand everything about our universe we cannot know for certain whether an anomaly is a "glitch in the program" or simply a lack of true understanding about the nature of the anomaly. If the anomaly occurs in an area it is thought that humanity understands completely, scientists will assume the anomaly indicates that our understanding is not complete. They will then hypothesize and experiment with various explainations for the anomaly until they are satisfied that our understanding is complete - or at least "complete enough".

The "simulation theory" isn't even a recent development. The idea that our entire world/galaxy/universe is simply a dream or toy or the like of some greater being has existed for centuries. The recent development is just that "computer simulation" has been tacked onto the list.

Re:The Simulation Argument

[Naysayer]

No, the recent development is the probability part of the argument. There's a big difference between saying "wow man, the whole universe could just be in a compuuuter somewhere", and saying, "if you look at the probable branching factor of simulation creation, it's pretty clear that simulated universes vastly outnumber 'real' universes, unless we have a fundamental misunderstanding."

BOOM

[not_a_george]

If the universe collapses in a big BOOM, and everything is wiped out and no living life is left to hear it, will it make a sound?

It really doesn't matter

[tcape]

God IS real. No matter how far we get, we still won't know the truth till we realize God is real and start seeking the Science of God. You might think I'm full of crap but look around... Look at the paranormal---- Too much evidence to discount it entirely. So... if there is an unseen dimension or world or whatever you wanna call it out there, than there's probably a whole bunch of other stuff we have no clue about... We just see the physical.. we have no clue... Why doesn't science investigate how someone can forsee events.... Why doesn't science investigate psychokinetics... Why doesn't science investigate...telekinesis Why doesn't science investigate why prayer works... Because it goes against scientific logic... forces them to believe in what they can't see... They can't do that... Ask any real, I mean REAL Christian and they have no doubt about the existence of God.... I'm not perfect, I do things I'm not supposed to, I mess up all the time, but I believe and continue to strive to do better... That's all... I think all God wants us to do is admit he exists... once we do that, it changes your whole out look on life.. Lets see.... my life sucks, what can I do about it? If God is the God he says he is...all I have to do is make a human attempt at what he wants me to do and he will take care of the rest... Wouldn't having a supreme being on your side make life a little more tolerable? Believe it or not it does work.... The only way to know for sure is to try it....

Re:It really doesn't matter

[Anonymous Coward]

Ask any real, I mean REAL Christian and they have no doubt about the existence of God

Ask any real, I mean REAL Scientologist and they have no doubt about the existence of Body Thetans.

Re:It really doesn't matter

[Anonymous Coward]

Ask any real, I mean REAL Muslim, and they have no doubt about the existance of Allah.

Re:It really doesn't matter

[Anonymous Coward]

Prayer works?

Let's test that, shall we?

I want to to pray, as hard as you can, for the sun to turn green - not forever, just a week.

Hey, you can prove the effectiveness of prayer AND prove the existance of Apollo, I mean, Ra, no, I mean Jesus - all at the same time!

What are you waiting for? Get to prayin'!

Re:It really doesn't matter

[jwonase]

Cool idea - but please don't have everyone from slashdot do it at once...

Good, but old hat

[eclectic4]

Sorry, it's just that this info is old hat to anyone who keeps up on astro-phys stuff. In fact, SciChannel has had some very good, well produced shows about these very things for quite some time now.

I don't mean to be a bubble burster, it's just that this stuff was "revealed" quite a bit ago.

Re:Good, but old hat

[Anonymous Coward]

You were expecting ground-breaking revelations on Slashdot? Or is this just the affected ennui of "those in the know"?

Re:Good, but old hat

[Anonymous Coward]

What do you expect, they asked a science journalist about direct science questions, which are worthy of a scientists answer.

What's next, an Ask Slashdot session about efficient data tree search algorithms from the CFO of Oracle?

Re:Good, but old hat

[Stuntmonkey]

Sorry, it's just that this info is old hat to anyone who keeps up on astro-phys stuff.

I agree, but this is mostly the fault of bad moderation. Some of the questions were actually quite provoking if you read them. The fact that only the softball RTFB ones got modded up is a punishment we inflict on ourselves.

Bubble Bobble

[Anonymous Coward]

If our universe isn't infinite, then it has borders. If it has borders, then it has a shape -- similar to a bubble, perhaps.

Now imagine a child with a runny nose. This snot nosed brat has created two bubbles, one blowing out of each nostril. Could it be that our universe represents snot bubble #1, with snot bubble #2 representing another hidden universe?

For those confused by the above:

Hidden Universe != Uranus

-SW

Re:Bubble Bobble

[Anonymous Coward]

If our universe isn't infinite, then it has borders.

I know your post was a joke, but for the scientific benefit of other readers: the Earth's surface is finite, but if you sail or walk across it, you never reach "the edge of the Earth". Extend this analogy up one dimension to space as the 3-dimensional hyperspherical surface, instead of the Earth's 2-dimensional spherical surface, and you will have an example of a finite but unbounded space.

Re:Bubble Bobble

[praedor]

Nice. Using your analogy, I don't WANT to know the answer, I don't even wish to hear the question anymore.

And for god's sake, give the little shit a kleenex.

Re:Bubble Bobble

[Anonymous Coward]

I employ the "SpaceWar" theory: When you cross over the edge of the universe, you appear on the opposite side. (See: Mario Brothers Theory)

Bummer...

[FroMan]

Douglas Adams is dead, so he won't be able to update HHGTTG and the milliways stuff.

I wonder...

[SifuDave54]

is it possible that there are life forms consisting of dark matter that are just as oblivious to our existence as we are to them?

I'm not talking about exotic forms of conciousness created sporadically from energy or those sorts of things. I'm talking about life as we know it.

Or does current dark matter theory rule out the idea of life as we know it existing in dark matter?

Re:I wonder...

[T4D]

Sigh... You are Dark Matter. Dark Matter is mostly just a term cosmologists used to refer to matter that cannot be seen with a telescope. Planets orbiting other stars cannot be directly seen because they are too small and do not emit/reflect enough lisgt to be seen by our telescops. The ather part of Dark Matter is particals (like the LSP mentioned) that are heavy, cannot be seen, but interacts with gravity.

So yes, there are life forms consisting of Dark Matter that are as oblivivious to us as we are to them. They are the people that DON'T read Slashdot.

The Pluto Analogy

[mike_mgo]

I think this analogy is flawed.

The reason people accept that the Newtonian prediction that Pluto will take 250 years to revolve around the sun is that there are plenty of other planetary bodies that are observed to follow those rules. But in the case of the ultimate fate of the universe we obviously have no other reference to compare this theory to. I realize that there probably are verifiable predictions the theories do make (birth and death of stars/galaxies) but the ultimate result can never be checked.

I'm not trying to imply that this theory is wrong, just that there are always likely to be questions raised since it is ultimately unverifiable. Obviously bits and pieces (probably even the majority of it) can be confirmed, but we'll never be able to say, "This theory acurately depicted the ultimate death of Universe Alpha over there and that's going to be the same fate as our universe."

Re:The Pluto Analogy

[Anonymous Coward]

I think we could still safely conclude that Pluto will take 250 years to revolve around the Sun, even if there were no other planets, if we had enough detailed data about its orbit (which we do). Likewise, with the advent precision cosmology, I think we can make some decent inferences about the long-term fate of the universe.

Re:The Pluto Analogy

[jonhuang]

And let's not forget the really big assumption of science:

"That which happened in the past will repeat itself in the future." How do we know this? Because it has always been true in the past.

Re:The Pluto Analogy

[gotscheme]

One thing I fear is that if we are being pulled in a certain fashion such that our equations only hold up under our own logic--for example, the concept of relativity works because that is the logical conclusion we are faced with given the parameters of our logic--then we may have not actually described reality; instead we have created a model that approximates reality through our perception. That is not to say that there isn't some ultimately correct model, just that we may not be able to reason about it due to the setup of consciousness. In other words, some other organism (organic or otherwise) may have a more correct way to reason about the formation and destruction / rebirth(s) of the universe because of its inherent properties. So, in a sense, maybe it would be useful to try to find ways that other systems could reason about our universe. Maybe that is done by proxy already since a lot of equations come from natural systems. Anybody have a good knowledge of the literature on this kind of thing?

I guess our approximations are close enough to do a lot of good for us, and in some ways that is more important.

Re:The Pluto Analogy

[renard]

...the really big assumption of science...

As opposed to, say, the really big assumption of your going to sleep each night and expecting to wake up in approximately the same body, and approximately the same bed, with approximately the same house around you, and approximately the same sun up overhead?

How do we know this? Because it has always been true in the past.

1. It's not knowledge; it's a prediction. And as far as that goes - so far, so good.
2. If you've got a better idea, I'm all ears.

-renard

Re:The Pluto Analogy

[renard]

You may want to pick up the author's actual book. In addition to predicting the fate of the universe, the so-called "Concordance Model" of cosmology makes a number of other, eminently testable, predictions.

One of these is the presence of dark matter - weakly-interacting subatomic particles that even now are (most probably) streaming through your body at the rate of millions per second. We have the technology, now, to search for these, and if we find them (give it a few years) - score another one for the model.

This is just one example - cosmology and the dark energy being extremely active areas of current research, there are in fact dozens of research projects under way to test the predictions and assumptions of the Concordance Model. Any one of these could disprove the theories and send everyone back to the drawing board - and our conclusions would be subject to revision in that case.

In the end, of course, we cannot know the fate of the universe until we get there - we can only give it our best guess. But, again, we can't know that Pluto will actually complete its full 250-year orbit, either, until it actually does; we can only give it our best guess.

So I think the analogy is quite apropos.

-renard

Re:The Pluto Analogy

[reidbold]

We don't know it, we assume that under the same situation, things will react the same way. We go with this until we're proven wrong/find out something new we didn't know before.

If you don't want to accept this premise then there's really no reason to believe that in 2 seconds everything you know will cease to exist or any other of the infinite possibilities out there.

Re:The Pluto Analogy

[Anonymous Coward]

Dave, Bertrand. Bertrand, Dave. I'll be over here.

Best interview for a long time

[panurge]

This is one of the most sensible, hype-free essays - because it is, virtually, an essay - about cosmology. Too many journalists go apeshit over ideas like infinite universes and present them as if they were completely mainstream cosmology. This seems to be a very balanced account. (And the point about Thomas Kuhn is very well made. I had to stop and think about it, then I found I was in complete agreement.)

We need competent journalists and technical writers to explain cutting edge science to us just as, though we hate to admit it, we need competent marketing and sales people to sell software.

Re:Best interview for a long time

[Innova]

We need competent journalists and technical writers to explain cutting edge science to us just as, though we hate to admit it, we need competent marketing and sales people to sell software.

Agreed. When you find a competent marketing person, please send them my way, I have this project that could use them......

Re:Best interview for a long time

[Takatsuki]

I like the Kuhn point too. I personally think Kuhn's idea of paradigms is brilliantly insightful and i make use of the concept constantly. At the same time, i totally disagree with the degree to which he takes it, as described well here. If Kuhn were right all science would be a subjective social construction.

Wil Wheaton frozen?

[ENOENT]

I guess that explains his acting style.

What's the rush?

[Euphonious Coward]

So, everybody agrees that the universe has billions of years left on its meter.

So, what's with the rush to pin it down now? The experiments being run now would be thousands of times cheaper if we waited thirty years, or a century. Why not run them when they're cheap? Maybe after a decade we'll realize we don't need them at all, and that some other experiments would be more useful.

Furthermore, why do we need a thousand cosmologists, or a hundred? Seems like a dozen should be enough. Sure, it would be less fun for the rest to spend their time working out fluid flows around funny wing shapes, or whatever physicists do nowadays to try to make themselves useful. Their fun is their business.

This isn't a question about the usefulness of basic research, but about timing. Lots of immediately meaningful basic research is going undone because of the huge budgets of physicists in a hurry. Lots of the neglected research might have equally profound effects on both our understanding of the universe and on future industries. So the question is, again, what's the damned hurry about cosmology?

A side question is, why should a cosmologist care whether the idea of a truly infinite universe makes anybody uncomfortable? Anybody who wants comfort can believe we live on the back of a big turtle, and sleep soundly.

Re:What's the rush?

[Anonymous Coward]

what makes you think that all all the technology to observe space will be cheeper in 100 years... in a hundered we will still havent done any research into creating tools to do cosmilogical recharch with so it will still be expensive becuse the r&d needs to be done.

thats like saying.... noone buy any cpu's for the next 3 years, beause then we can get the 3200 for really cheep! well then amd and intel will stop doing r&d if noone is buying cpu's and in 3 years when you want your $30 3200+, it will still be top of the line and expensive... why would intel and amd bother to lower the price if its already set? :|

any way thats my opinion, and the analogy doesnt quite fit but it gets the point accross

Re:What's the rush?

[Ingolfke]

The real question is when will this danged turtle die or the one underneath him or the one underneath him? With turtles all the way down... my gosh it could be immanent! How can anyone sleep soundly w/ that on their mind?

Re:What's the rush?

[praedor]

Well, the universe may have a few tens of billions of years left but WE don't. Not even close.

There is one postulate that "we" have somewhat less than a few 10s of millions of years - long before the sun expands into a red giant and consumes earth. The geochemical cycle that is REQUIRED to keep water on the surface will not work more than a few more million years. The oceans will be lost into the earth and water locked up in rocks. The surface a dead, dry husk. Long before it gets to this stage, we will be well and fully finished as it wouldn't be OK up to the point that the last drop of liquid water is lost, it would get quite inhospitable long before then.

The sun gets hotter with every passing year. Long before it enters its final stages of red giant followed by white dwarf, it will be too hot to allow life on earth.

No species lives more than a few thousand years and this must likely include modern humans. Though the dinosaurs ruled the earth for many 10s of millions of years, no single species of dinosaur lasted anywhere near that long. Every single one of them died out and was replaced with something else. I suppose the closest things to eternal species - those that are essentially the same as when they first evolved into their present form - would be bacteria, cockroaches, and a few other insects. Perhaps a few fungi could be included too but nothing else.

As far as I'm concerned, it doesn't count if some human ancestor that isn't really us comes along in the future - that doesn't do jack squat for US and it is US that wants to know the answers. I couldn't care less about the idea that a post-human species follow-on may have the answers we seek, that doesn't do me or you any good at all and it doesn't satisfy current curiosity and desire for knowledge. In practical terms, a hypothetical future descendent is irrelevant as it has no bearing on us today and has no effect on us. WE want the answers.

The argument is equally well illustrated if you posit that there is, somewhere in the galaxy, another species of technically advanced animal that has the answers to the questions we are seeking now. So what? What good does that do us? Let it slide and just be happy that someone, somewhere or when else has/will have the answers? Not good enough.

Re:What's the rush?

[jellisky]

I don't necessarily think that there's a "rush," per se. It's just that it's a curiously interesting subject and that a lot of people are interested in it.

Scientists are most happy when we (yes, we) are able to do the research that interests us. Is it really fair to dictate what scientists have to research (outside of subjects that have deeper moral implications)? Where would we be if Einstein was told that he had to study the causes of friction or something like that, instead of letting him explore high energy and relativistic physics? Or any other scientist?

Scientists, like any other person, wants to do a job that makes them happy, and if they can find someone to support them to do it (research grants), they'll jump at the chance. If you really wanted to code games or write up that novel in your head, wouldn't you jump at the chance if it presented itself to you? So, why should the cosmologists not do what interests them, especially if they can make a living off of doing so?

And more importantly, why can't they do it at their own pace? Science's progress, when given freedom, cannot truly be predicted. Some fields can languish in "mediocre progress" for many decades, then suddenly explode in a rush of progress and knowledge. (Look at any history of mathematics book for examples of these... calculus and analytics have had a few periods like this.) Cosmology is no different. They've been free to answer their questions and have suddenly found that they can start answering them quickly now. Is there anything fundamentally wrong with this?

Lastly, about the "expense"... remember that "necessity is the mother of invention". It's a fallacy to believe that the tools the scientists use now would be any cheaper in the future, since many of these tools require machinery and equipment that are often not mass-produced and would probably never BE mass-produced. The nature of scientific tools are that they are often relatively unique and frequently have only moderate to limited use in larger industry. After all, how many industries could use the inner workings of a super-collider's detection unit? Some tools, yes, are mass-produced now and could be cheaper in the future, but I would contend that many wouldn't be. So, if no industry is going to invent these tools since they don't need them, why would they be cheaper in the future than now if the only reason that they are built and invented is because scientists needs to use them for their research? They still will have to be specially-built. Granted, you may get more "features" or cheaper manufacturing... but how many advances in those fields have been spurned, in the first place, by the unique engineering needed to built these instruments? Wouldn't you also lose those advances, or hinder your knowledge of those advances? In other words, it's a bit foolish to believe that "future" scientific tools would "cost more" than current ones.

-Jellisky

Re:What's the rush?

[Ken Broadfoot]

It gets even better...

We, as a race of people, may have a few million years left. As Americans, we may have only few hundred left. As individuals only a few years left.

Kind of makes a possibly changing
"fine structure constant" irrelevant.

Got to go... "All my Children" is coming on.

--ken

Re:What's the rush?

[Rocky]

Well... I guess we need to keep the physicists employed somehow.

Otherwise, they'll be working on things like doomsday weapons and re-animating dead cats...

Re:What's the rush?

[RatBastard]

No species lives more than a few thousand years and this must likely include modern humans. Though the dinosaurs ruled the earth for many 10s of millions of years, no single species of dinosaur lasted anywhere near that long. Every single one of them died out and was replaced with something else.

This is absolutely untrue. While many species do just die out, many evolve into something else. There is no time limit on species. Any species will continue to thrive, or at least get by, until environmental forces either kill off the population or force the population to adapt and therefore evolve into another species.

And as for the "severl thousand years" limit, utter hogwash. While homo sapiens (modern man, but I don't have to the people here that) have only been around for some 50,000 years, neadnerthall man lived in Europe for 200,000 years. Going back further we fiind that the T Rex roamed North America for at least five million years. Even further back we find that the trilobites ruled the shallow seas for some 250,000,000 years and had some species that survived (as best as we can tell) for upwards of tens of millions of years. And then we have the coelacanth, an ancient speces of fish that has been around for some 400,000,000 years and still swims the deep ocean depths to this day.

Re:What's the rush?

[Anonymous Coward]

So, what's with the rush to pin it down now?

Because they can. :)

suggestion to the editors

[joepa]

When the answers to an interview are this extensive, it is perfectly acceptable to span an article over multiple pages.

Best. Article. Ever.

[yotto]

I truly think this is the single best thing I've ever read on /.

I think I'll head out to buy this book now.

An objection

[Anonymous Coward]

Despite his careful response, I still have problems with his claim that we "know" how the universe will end. If the dark energy really is a cosmological constant, then that's a fair assumption. But we don't know what the dark energy is. If it's a field that dynamically generates an effective cosmological constant, than the long-term fate of the universe depends on the properties of that field. Since we don't even know yet whether it is a field, I think it's still too early to say that we have real confidence in how we think the universe will end.

More black holes?

[Viking Coder]

Okay, so there's this Big Bang, right?

Well, what in the hell stopped all of the matter from forming a black hole and falling in? It was certainly dense enough! WELL beyond the Chandrasekhar limit. (By about, oh, 10^122, right?)

I've read that you can think of the entire universe as existing inside of a black hole - that kind of explains the "shape" of the universe, and why we can't see "outside" - but black holes leak radiation! (Hawking Radiation.) Where the heck would the UNIVERSE leak radiation to?

If the universe is leaking radiation, wouldn't that mean that there's less and less matter INSIDE of the universe, and therefore, less gravitational pull, and therefore, wouldn't that explain why the rate of expansion is increasing?

I know I've built a lot on a few assumptions; the point wasn't so much that the conclusions confuse me, but that I can't figure out where I got derailed from being correct! Start from the beginning, why didn't all of the matter in the universe fall into a black hole, right after the Big Bang?

HELP!

Re:More black holes?

[Anonymous Coward]

Contrary to popular belief, there isn't any law of physics that says that matter compressed past a certain density must form a black hole. And no, our universe isn't really analogous to a black hole. Try this FAQ.

Re:More black holes?

[Viking Coder]

Thanks for the link, but I think it was horrible. This single line in particular, "The Schwarzschild limit does not apply to rapidly expanding matter" strikes me as utter tripe. I don't see any apologies in the Schwarzschild formulation for "rapidly expanding matter."

And the entire point of a "black hole" is that there's too much gravity for anything to escape. The "law of physics" that is used in the "popular belief" is gravity. What am I missing here?

Also, Hawking Radiation predicts an end to black holes (specifically, their black-body radiation, and their duration), contrary to that FAQ's statement that "black holes cannot be destroyed". I don't buy it. I guess you'd have to point me at refutations of Hawking Radiation...

Re:More black holes?

[Anonymous Coward]

Thanks for the link, but I think it was horrible. This single line in particular, "The Schwarzschild limit does not apply to rapidly expanding matter" strikes me as utter tripe. I don't see any apologies in the Schwarzschild formulation for "rapidly expanding matter."

Yeah, well, frankly, what makes you think you know enough about general relativity to judge?

I have no idea of what you mean by "apologies in the Schwarzschild formulation". Are you referring to the Schwarzschild solution of the Einstein field equation? If so, there is no reference in that solution to rapidly expanding matter because that solution doesn't have any rapidly expanding matter. Big Bang solutions do, though. If you're referring to some claim of Schwarzschild that sufficiently dense matter must form an event horizon, there is no such claim.

Here are two indisputable facts:

1. Friedmann-LeMaitre-Robertson-Walker cosmological models are valid solutions to the Einstein field equation.

2. They don't have any event horizons.

They are an obvious counterexample to your claim that the Schwarzschild limit applies to all concentrations of matter. If you think otherwise, you're fighting a mathematical truth -- but feel free to present a proof of a theorem that states otherwise. You're the one who claims that there is such a result, after all -- in what paper or text may it be found?

And the entire point of a "black hole" is that there's too much gravity for anything to escape. The "law of physics" that is used in the "popular belief" is gravity. What am I missing here?

You're missing the fact that there isn't any gravitational law of physics that says that high density => a black hole. That's what the FAQ said.

Also, Hawking Radiation predicts an end to black holes (specifically, their black-body radiation, and their duration), contrary to that FAQ's statement that "black holes cannot be destroyed". I don't buy it.

Try reading the whole FAQ. If literacy isn't your strong suit, try searching that document for the text "Hawking radiation".

Re:More black holes?

[entrager]

As I understand it, current big bang theory does say "a really dense ball of matter exploded." If that was the case, then your argument about the Chandra limit would make (some) sense.

However (someone correct me if I'm wrong), currently the big bang theory is closer to "the three dimensions we live in suddenly became much larger." Think of it this way: Say you have a few small magnets. When you place them close together they will all collect in one big mass. This is similar to what matter will do under the force of gravity. Now place those magnets on a rubber sheet, close enough so that they will attract. Hold them in place so they don't move (think of this as a frozen moment in time). Now let the magnets go but suddenly stretch the sheet in all directions. Despite them being close enough initially to attract, the sudden stretch in their "space" will separate them enough to prevent the attraction. However, each one remains stationary relative to their location in "space" since "space" itself is expanding.

Does that make any sense? Basically, the matter wasn't propelled outward by some force. Instead, space itself expanded (and still is? Maybe?)

Of course, I'm no physicist. But I wrote a paper on M-Theory in my black holes class last year. :) Anyone care to set me straight?

Re:More black holes?

[entrager]

Oops! That first line is supposed to say "current big bang theory doesn't say".

Re:More black holes?

[Anonymous Coward]

Yes, you're correct. The Big Bang was not an explosion of a ball of matter into empty space; it was the expansion of space itself, and a uniform distribution of matter within it.

Re:More black holes?

[araemo]

"Hawking Radiation" is not actually coming from inside the black hole.

According to the theory(which I read a LONG time ago.. I could be mistaken), matter and anti-matter particles randomly 'appear' in pairs(which is basically stated in quantum mechanics as being a matter of course).. Hawking radiation is when one particle of the pair is sucked into a black hole, and the other narrowly misses it.. now theres an extra particle that is coming from the general vicinity of the black hole, this is the radiation that is observable.

However, I think the universe being inside a black hole would explain why it's flat.. I seem to recall the idea that black holes are flat(well.. how can a singularity be shaped? but thats way beyond me.)

Re:More black holes?

[Viking Coder]

I really do appreciate your attention to my questions, and I really do wish I knew enough about Friedmann-LeMaitre-Robertwon-Walker cosmological models to understand why you think that they're a mathematical truth that I'm fighting. I don't know anything about them though. You're addressing a layman who's asking a question.

To lend the tiniest bit of weight to my side of the question, first I'll quote you, and then I'll quote the end of the FAQ you keep refering me to, as though I'm illiterate:

You: "And no, our universe isn't really analogous to a black hole."

FAQ: "This idea is controversial, but if true it would mean that the universe could be both a white hole and a black hole at the same time."

So, that FAQ seems to say that what I'm saying is controversial, but it doesn't say that I'm WRONG, like you're saying.

Yeah, well, frankly, what makes you think you know enough about general relativity to judge?

Nothing, frankly.

I suppose the real problem with my thinking is that the universe did not need to support its "initial" size with something like electrons providing degeneracy pressure - which would have failed, because there was so much mass (not to mention no freaking electrons). The real question in my question, I guess, is, what provided the pressure (ie expansion) to prevent the universe from collapsing into a black hole?

The layman's understanding that I have says that, if there's enough gravity, there's nothing that can get away from it - the speed of light isn't "fast" enough - space is too curved, time falls in. You'd think (with layman's understanding) that all of the matter and energy in the entire universe would provide enough space-time curvature to make sure that nothing could escape. If there are good, solid, mathematical and cosmoligcal explanations for explaining why that's not true, than I acknowledge that I don't know enough to disagree with the experts. But all I was doing was asking a question.

Again, what provided the pressure (ie expansion) to prevent the universe from collapsing into a black hole?

Which is kind of like asking, "where did all of the mass and energy in the universe come from?"

I suppose I'm just giving myself an execuse to not have to try to defend my ignorance, but after all, I was asking a question to which there really is no answer. I don't really need you to call me illiterate to tell me that there's no good answer to my question, do I?

Re:More black holes?

[Viking Coder]

Yeah, thanks - I pretty much knew all about that, but I kind of rushed to post my question.

Still, in Hawking Radiation, the black hole does loose mass over time, eventually ending entirely - which is where I got to in the end of my argument/question.

It's kind of fun as a layperson to knock these ideas around, but I know I'm just dabbling in dangerous waters filled with equations I'll never understand. =)

Re:More black holes?

[Viking Coder]

Okay, so I'll pose my question another way, why did "space" itself expand?

And why did that expansion, in essence, make the universe so that it WASN'T curved into a singularity?

In other words, my question really is the big unanswerable one, "Where did all of the energy and mass in the universe come from?" :)

Thanks for your explanation, though... I recently saw Anthony Lasenby talk about the shape of the universe in a fascinating talk, and it was fun to think about. As with all great persuits, his talk left me with more questions than answers.

Re:More black holes?

[Anonymous Coward]

FLRW models are not a "mathematical truth" -- the universe doesn't have to be described by FLRW models. But it is a mathematical truth that FLRW models are Big Bang solutions of general relativity that do not have event horizons, so it is not true that general relativity requires the Big Bang to form a black hole.

No, we can't definitively say that you're wrong and the universe is not a black hole. But the FAQ is a bit out of date; the idea that black holes are time symmetric with white holes is even less popular now than back then when it was merely "controversial".

We don't know what provided the initial expansion of the universe. It's only an assumption that the Big Bang would have had to start out "at rest"; the universe could have started already in motion. We don't have a good theory of initial conditions (and there may not be one), so right now we have to simply postulate that it started out with a high expansion rate. We don't know where all the mass/energy came from either.

(It may not even be a meaningful question; merely asking it implies that there was a time when there was no matter/energy, and then suddenly there was some. But if there was a beginning of time, then there was no time at which matter/energy did not exist.)

Analyzing what happens to a concentrated region of matter under the influence of gravity is not a simple matter. All I can say is that strong gravity does not -- at least immediately -- counteract fast motion. (If the initial expansion of the universe were slow enough, then the gravity would eventually cause the univese to recollapse -- but even then it doesn't form a black hole; the singularity structure of a Big Crunch is different from a black hole, and there is no boundary between "inside" and "outside" an event horizon that you need for a black hole to exist.)

There was an answer to one of your questions, by the way: the answer to your question about whether the density of matter in the Big Bang must produce a black hole is "no". Big Bangs don't have to produce black holes. (Whether ours did is another matter.)

P.S. I would've given you a more civil answer if you hadn't derided the link I gave you as "utter tripe" without having a shred of an argument to back it up.

Re:More black holes?

[Viking Coder]

I think it's actually, "near-uniform". Apparently people think that the large-scale structure of the distribution of galaxies, etc., can be seen as evidence that the matter at (or very near) the beginning of the universe was non-uniform. Perhaps on the scale of Heisenberg Uncertainty. At least, according to Anthony Lasenby, who I heard speak at SIGGRAPH 2003.

Re:More black holes?

[Anonymous Coward]

Current thinking is that large-scale structure formation is due to irregular quantum fluctuations in an otherwise uniform inflaton field. See the text by Liddle and Lyth.

(i.e., it started out uniform, and then quantum fluctuations appeared and were amplified by inflation).

On the other hand, there are other theories, like Linde's chaotic inflation, that hold that the universe was never uniform; it's just that inflation acted upon a locally smooth piece of an otherwise chaotic "sea".

Re:More black holes?

[Viking Coder]

Cool.

Yeah, I believe in the speed of light being constant - and I believe that space-time can be so curved that light cannot escape that region. (Effectively making time stop to zero, or to flow in the other direction.)

Throwing in the phrase "rapidly expanding matter" only pisses me off. That seems to say "sometimes, matter can go FASTER than light!" =) That's where the thought "utter tripe" jumped into my head.

The way I can see the argument, though, as another poster mentioned, was to think not of "rapidly expanding matter," but of "matter which exists in space that is rapidly expanding." It doesn't get me much closer to understanding, though...

To skip to your first point in this post, another way for me to insert "event horizon" into Big Bang solutions, is to look at the definition of an event horizon - "The event horizon is a boundary beyond which information will never reach an observer." I can see that as saying that "information will never reach someone outside of the universe." In other words, "An observer can't be outside of the universe." I don't think I used any clever semantic tricks in that argument, I'm just saying that, if our universe were (inside) a black hole inside of another universe, we could never know about it, and an observer in the larger universe would never get any information from inside our universe. Do you see where I'm going with this one?

I'm not saying the event horizon is caused by a gravitational singularity that we can observe inside our universe - I'm saying that we couldn't tell the difference between our universe existing inside of a gravitational singularity of a larger universe.

I'm confusing things by talking about this "larger universe," which I don't actually think exists. I'm just saying that my limited understanding of black holes and my limited understanding of the Big Bang lead me to believe that you can think of our universe as existing inside of a black hole. I guess I shouldn't actually say "black hole," here, though. I should say that I think that nothing will ever escape our universe (by moving away from it, anyway - I'm not talking about black holes in our universe), that space-time in our universe is curved but infinite, that expansion is accelerating, that the universe will burn out, rather than crunch back. All of these things are consistent with my understanding of a black hole (or at least, what MIGHT be happening, on the INSIDE of a black hole). Not necessarily a "gravitational singularity," but just a "singularity" of some sort, with an event horizon. *shrug*

Yeah, I'm talking as though there can be space within a black hole, where the very definition is a point singularity... *shrug* My layman mind is comfortable with that. =)

Thanks for the conversation, though. Like I said, I really do appreciate your time and thought on this one. I wish I could speak in person with someone who could help me understand some of these questions... I'd pay good community college money for something like that! =)

Re:More black holes?

[jorhan]

Two things to point out:

The universe was much less massive than it is now. The currently favored models are inflationary.

In order to describe the first momments of the Big Bang, you are going to need a good theory of quantum realativity. Unfortunately, no one has one.

That actually would have been a really good question for Mr. Seife, "What are the current best theories for reconciling Quantum Mechanics and Relativity? Or what are the prospects of such a theory coming together in the near future?"

Re:More black holes?

[Anonymous Coward]

The way I can see the argument, though, as another poster mentioned, was to think not of "rapidly expanding matter," but of "matter which exists in space that is rapidly expanding."

Yes, that's the right way to think of it. In general relativity, there is a light speed limit on how fast matter can travel through space, but there is no such limit on how fast space itself can expand (carrying matter along with it).

I don't think I used any clever semantic tricks in that argument, I'm just saying that, if our universe were (inside) a black hole inside of another universe, we could never know about it, and an observer in the larger universe would never get any information from inside our universe.

Yes, but there are other problems. Black holes tend to be inhomogeneous in their interiors (they have a center), but our observable universe does not appear to. Plus, black hole interiors have a singularity in the future, whereas the Big Bang is a past singularity.

I'm just saying that my limited understanding of black holes and my limited understanding of the Big Bang lead me to believe that you can think of our universe as existing inside of a black hole

You might be able to construct such a model, but it would be tricky and probably contrived; you have to address the previous points.

Yeah, I'm talking as though there can be space within a black hole, where the very definition is a point singularity...

No, the definition of a black hole is a region enclosed by an event horizon. There is certainly space within a black hole, and inside that space is a central singularity.

Re:More black holes?

[Anonymous Coward]

"What are the current best theories for reconciling Quantum Mechanics and Relativity?

The two main contenders are string theory and loop quantum gravity. Here is a (technical) review paper summarizing them and most of the other approaches. You can find more lay-oriented information on them around the web, too.

You might also like to read a somewhat outdated discussion of various models of quantum cosmology.

You Heard It Here, Folks -

[n8willis]

That's the big open question, but one that I'd wager will be solved by the end of the decade.

All that remains to be done in physics is the working out of a few physical constants, kids, go study something else with a better long-term outlook.

Put the bong down Dude

[Anonymous Coward]

You've had enough for one day.

Re:What are we playing jeapordy now?

[Anonymous Coward]

Yeahporky?

Re:Wait A Minute..

[Anonymous Coward]

What do you expect from a /. Q&A segment about the future of anything. The future is undecided.

So /. is just a giant magic eight ball?

Agreed. Now how about...

[Atario]

Followups?

Ferinstance: I've read for some time about the idea that all of space is filled with a super-duper tiny froth of particle-anitparticle pairs spontaneously forming and mutually annihilating. Couldn't all these particles, even though they exist for short times, exert gravitational (or other) force and account for some missing mass? Maybe even the "dark energy"?

Re:Wait A Minute..

[ihummel]

Yes! That's a perfect assessment! I might even put something like that in my sig, if you don't mind.

Re:Agreed. Now how about...

[Anonymous Coward]

Your proposal is essentially the idea that vacuum energy is responsible for the cosmological constant. You can read about that idea in this FAQ. So in that sense, yes, your idea is a contender for explaining "dark energy". Unfortunately, naive calculations give a prediction for the cosmological constant that differs drastically from its measured value, and we don't know how to to do a better calculation. This is the infamous cosmological constant problem of cosmology.

What I've allways wondered...

[Damon C. Richardson]

I actually accepted the idea years ago that the cosmos ( as we know it ) will expand into the cold void.

But I'm wondering.... Will matter speeding away from our big bang some day combine with matter from a totally different bigbang.

Or even better! What if we could jump off this cosmos and join another one!

Correction

[Anonymous Coward]

Ooops. This FAQ.

cool

[kryzx]

I'm just glad to hear that "the universe is a pretty cool place."

If I found out I'd spent my whole life somewhere uncool that would just be depressing.

Re:cool

[Anonymous Coward]

Well, I guess we won't point out that you're posting this on Slashdot... How much time do you spend here anyhow?

Re:cool

[Anonymous Coward]

If I found out I'd spent my whole life somewhere uncool that would just be depressing.
You mean like Iowa?

Re:would it have been so hard...

[Anonymous Coward]

OH CHRIST you'll have to click one more link! What will we do? Shit, my mouse wasn't cut out for this!
Just because your big ass fatfingers your mouse buttons is no reason to burdgeon all of us with your petty complaints. The editor's note specifically said to email him with you complaints. Fucktard.

Frozen?

[WTFmonkey]

I always thought the opposite-- flaming!

Bizarro slashdot?

[putch]

a ./ if you will, where a monolithic corporation is defending the gpl and linux is criticized.

wait, today's page must have fallen through a wormhole.

Re:Bizarro slashdot?

[Anonymous Coward]

you would also see:
1. In Captialist America...
2. phase 2 would be filled in, followed by phase 3: Profit!!!
3. Don't imagin a Beowulf cluster of...

Weird coincidence

[eaddict]

I started reading this as my CD player started the soundtrack to Men-In-Black. It was weird reading about all the space this and telescope that and having the theme music going.

I ought to patent reading AND listening to music at the same time. Slashdot having theme music? It would be funny to put a recommendation to play while reading a story..

Stephen Baxter's Xeelee Sequence

[Donelurking]

That's more-or-less the subject of a series of novels and stories by Stephen Baxter. Titles include The Ring, The Time Ships, Vacuum Diagrams (my favorite). Truly mind-stretching stuff, taking place over billions of years. Sci-fi on a REALLY big scale.

How can they...

[Metal_Demon]

Know so much and yet know so little? Scientist think they know tons of things about this universe and yet nobody can prove or disprove the existence of aliens. How can you see a bajillion miles into space and not be able to zoom in on some hot alien chick in the tub on Venus? Doesn't it seem odd to you that they would know how we came about and how we will end without knowing if we are alone? On a final note, this is intended to be both funny and insightful and damn well better get modded as such.

Q6 - finite/container of the universe

[genericacct]

I think they both missed the concept that seems to explain it for me. First, I make a distinction between the 3-dimensional universe, and the matter in it from the Big Bang. Obviously, the latter fits inside the former, and there is no way to know (or compelling reason to believe) that there is any sort of boundary for the universe as a whole in literal 3-dimensional space. Since we don't see anything beyond the matter of the big bang and haven't travelled past it, then the _known_ universe (of matter) is expanding within 3-dimensional space.

But then, there is the independent concept that space itself is curved, possibly by the matter from the Big Bang, forcing travel in one direction to loop back on itself. Then there is only a boundary in a strange indirect way, if you can even call it a boundary.

Re:Q6 - finite/container of the universe

[Anonymous Coward]

I'm not sure, but I think you may be suffering from a misconception that the Big Bang started with a bunch of matter concentrated within an otherwise empty space, which then exploded into the void. Rather, the Big Bang was when all of space itself was compressed, and subsequently expanded. The Big Bang happened everywhere, so to speak, because all points in space were once concentrated in the same place. Space itself has been filled uniformly with matter/radiation from all time -- it's not a "shock wave" of matter propagating out into empty space, it's existing matter that's growing farther apart.

See also this FAQ.

More PR

[divisionbyzero]

From a philosophical perspective, these answers are pretty weak, however, it is an interesting survey of some recent advances in cosmology and it's hard not to appreciate the author's enthusiasm. Anyone who has read the history of science knows that every generation lots of people become convinced that science is closing in on the final answer. I'm not saying that we won't finally reach some theory that wraps all of the loose ends of all existing theories. We may or we may not, but the author provides no evidence that we will. This isn't the fault of the author. He provides no evidence of this kind because he cannot. To do so, he would need to know already what the final answer will be. What kind of evidence then does he provide? He provides evidence that some of the questions that are in fact artifacts of existing theories may have answers some time in the near future. None of this criticism is meant to suggest that we may not actually find a theory of everything. There is no evidence to suggest that we can't or won't, assuming theory is understand properly (i.e. subject to revision). My objection, if it can be called that, is not that this or that theory is right or wrong. It is about the philosophical structure of knowlege. I am suggesting that a book like this book amounts to little more than PR for educated people, and that's fine as long as it is understood as such. This kind of PR may even be considered necessary to stoke the enthusiasm of people in order to get support for this kind of research, but it shouldn't create unrealistic expectations. It also shouldn't be an excuse for ascribing any more authority to science than it rightly deserves. This comment may make some people nervous, but rest-assured I'm no Luddite. Would I read Slashdot if I were? I just see some absolutist tendencies and almost religious enthusiasm in the author's text that are completely inappropriate to science.

Re: More PR

[EvilTwinSkippy]

Indeed, these answers to life's questions are wholly unsatisfying. I would conjecture that to limit the behavior of the Universe to themodynamic behavior is a mistake. From a signals perspective, the sample of information we have, from a single viewpoint over the space of a hundred years does not allow us to extrapolate much of anything.

While vast, our models of the Universe barely contain a fraction of an infantesimal fraction of an improbably small amount of information about the universe. Conjecturing on its beginnings and end would be like me modeling the battle of Gettysburg knowing nothing of the weaponry, artillery, and/or tactics employed by both sides. Sure I could approximate the large battles, but war is won or lost by the efforts or failings of individuals.

A well placed sniper, an ill advised deployment of cannon, or a general with disintary can all shape the outcome, but they are monsterously hard to quantify.

Cosmological theories like this remind me of the joke about the Mathematician who models a horserace by first assuming the horses are sphere moving in perfect harmonic motion.

Big Rip!

[WolfWithoutAClause]

Actually, I think he's wrong about the universe dying in a cold universe. The expansion of the universe is accelerating, so as this continues the visible edge of the universe will come closer and closer over time (it's currently about 13 billion light years away, but it's approaching us). Eventually the visible edge will be closer than molecules- at that point all the molecules in the universe fall apart since the electromagnetism will no longer hold them together. Soon after, it will be smaller than nuclei- and then the weak force fails, and bye bye universe.

Re:Big Rip!

[Anonymous Coward]

No, a Big Rip doesn't happen for just any accelerating expansion, but only ones with special properties. The Big Rip idea is very speculative and the conditions under which it works are even more limited than previously thought.

Re:Wait A Minute..

[NulDevice]

So /. is just a giant magic eight ball?

Ask again later.

SCO angle to this?

[cant_get_a_good_nick]

So will SCO/Caldera die a heat death or an ice death?

Re:SCO angle to this?

[Anonymous Coward]

So will SCO/Caldera die a heat death or an ice death?

A dumb death.

The big question left unasked and unanswered

[Anonymous Coward]

Is the universe expanding fast enough to fill the chasm depicted in the goatsex links? Or is the universe doomed to always be able to fit well within its borders.

Read and Digest?

[Bobman1235]

C'mon now. You'll be lucky if 99% of the Slashdot community reads the COMMENTS at +4, let alone the entire interview. Look who you're talking to here!

The problem with the Sim & Doom Args ...

[watchful.babbler]

... is that they depend heavily upon a fundamentally indefensible assumption: that we can assume ourselves to be a randomly-chosen member of a given population that is invariant across time and space.

Basically, Bostrom's argument states that, assuming that the human population will continue to grow geometrically until it catastrophically declines (and thus assuming that the last human population prior to that decline is the largest set of living humans in history), you are statistically most likely to be in the final generation before the end of the world. The same argument, with slightly different assumptions (and you can twist the argument any way you wish, as long as you make different starting assumptions), is used in the Simulation Argument.

The problem is that it's incoherent by any measurement. After all, we are not plucked randomly from all over the time stream to form a statistically-representative sample, nor do we have any idea what the actual population distribution will be. The real nail in the coffin of Bostrom's thesis is that each person living before the final generation has a statistical probability of zero of being in the final generation, no matter the degree of their uncertainty as to which generation they belong.

To put it another way, Bostrom's argument is functionally equivalent to this: I have one hundred black marbles in this jar. In this other jar, I have one thousand white marbles that I will at some point in time add to the black marbles, in part or in whole. To Bostrom, if I ask you to guess the color of a marble drawn from the first jar at a specific point in time, you should always assume white. The problem, of course, is that you don't actually know the actual distribution of marbles: I may have added no white marbles, one, one hundred, or one thousand. Thus, we can drawn no conclusions from Bostrom's thesis. One guess is quite literally as good as another under such conditions of uncertainty.

John Barrow's paper (on postulated "glitches and small drifts ... in the laws of Nature over time" in a simulated universe) suffers from similar flaws. Yes, a simulated universe might experience small glitches as it attempts to regain homeostasis, if indeed a simulated universe allowed small glitches in the pursuit of homeostasis -- but that's tautological at best. (Who's to say that a simulated universe might not run perfectly, with completely rigid laws?) You can equally well argue that changes in an inflationary or deflationary universe will result in changes in assumed constants; for that matter, you can say that it's the will of God, the flutter of angel wings, or the acts of Douglas Adams' mice at work.

Like the work of too many philosophers who desperately want to prove that philosophy can triumph over physics (see Putnam, Hilary, and Searle, John), the Sim and Doom arguments try to argue to a conclusion from nonexistent premises. Most philosophers have trouble taking these arguments seriously; scientists should chuck them out the window entirely.

Re:The problem with the Sim & Doom Args ...

[RatBastard]

Another problem with these ideas is that the "system" would allow for errors to be detected by the "inhabitants". Any system suffiently complex to simulate the richness of teh universe we live in would more than likely have the ability to auto-correct errors and remove them from the memory of the system.

Consider the "Where the hell are my keys!?" glitch. Would the simulation really need to send you on a wild goose chase to find them while it bided it's time to find a place to put your keys? Why not just put your keys where you thought they were? Why not just freeze your process until it could figure out where your keys are and put them there before you notice they were missing.

On of the basic foundations for the simulation argument, as I have heard them, is that it explains these missing objects, deja-vu, vuja-de (the feeling that none of this has ever happened before) and other anomolies. This is not the expected behavior of a complex and powerful simulation.

Re:The problem with the Sim & Doom Args ...

[Naysayer]

I'll agree that the Doom argument seems clearly false, since it ignores the priors -- we have evidence about where in human history we live, therefore we are not a random sample. Any time you make a probability argument, you need to fully account for the priors.

In the Simulation Argument, though, there are no priors, or at least no obvious ones (aside from "at least one universe exists"). So if it is false, it seems to me that it would be false in a different way. "It sounds ridiculous" is not enough reason to discount a logical argument.

Well, screw it then....

[Ken Broadfoot]

If the universe is going to die, why bother studying it at all? Just when I get it figured out it will be a bit too late.
I think I will go back to poetry or something..

--ken

Oh the arrogance...

[jav1231]

I'm so glad we've discovered how the universe will end. WHEW! JAV

Why bother?

[Anonymous Coward]

Lot's of species live more than a few thousand years, but I get your point. But if our species is going to be dead long beofre this info could have any possible impact on us why are you so concerned if we know the answers. What possible importance can it have? At best it would just be some trivia question.

This assumes no intelligent intervention

[cyberlync]

This cold dead universe assumes that there will be no intelligent intervention. I am not talking about a mythical 'god' at all but more about advanced civilizations. Even humans will be a few tens of billions of years old by this time. Perhaps we or some other race decide a cold dead universe isn't a very happy place and initiate a universal reboot. Or they could be just redecorating ;)

All of this, of course, assumes that we are still around (very doubtfull) and that there are alians in the universe (unproven).

Re:What about support tiers?

[araemo]

Some people would say thats easy.. just look inside your self.. but ACTUALITY.SYS is harder (based on the idea that reality is your interpretation of actuality.. filtered through your consciousness.. I personally hate those terms, but thats just being picky.)

Homer was right

[sbillard]

...seem to imply that the universe is not only finite, but shaped like a donut

From the Simpsons episode where Lisa joins Mensa...
Begin Stephen Hawking voice
"You're idea of a donut shaped universe is intrguing. I might have to steal it
End Stephen Hawking voice

C:\DOS
C:\DOS\RUN
RUN DOS RUN
It's called the Dennis Miller quotient

Re:What about support tiers?

[araemo]

... I didn't change the title.. thats odd..

excellent interview, horrible format

[kaltkalt]

Great interview, but come on... 2-3 word "question summaries" before the answers? WTF? Is Slashdot trying to save electronic trees/hard drive space by not having the full question before the answer? Whose brilliant idea was this? I have an extra 100 meg hard drive lyin' around here that I'd be glad to donate to slashdot if storage is getting so tight that we need "question summaries."

Re:excellent interview, horrible format

[Anonymous Coward]

I'm actually torn -- this format worked well (IMHO) because the nature of how he answered the questions.

I'm not sure this will work as well with other interviewees.

At any rate, I'm sure this had nothing to do with storage space, just readability (and maybe you disagree on the readability thing, though I think it worked here great -- may not work in general).

Re:excellent interview, horrible format

[kaltkalt]

Well, he gave very detailed, factual answers that stood by themselves. This is true - we didn't need to go look at the question for the answer to make sense. BUT, it's still nice to see the question he is answering, and there's no reason not to put it there.

Bizzaro

[Anonymous Coward]

We should cut his whole body off

I don't get it

[QaDeS]

I'm far from being a scientist. As such, I just don't get why you have to introduce something new to make your models work (for some time), instead of taking what's there already:

- vacuum. I personally can deal with the idea that there's a room with nothing in it

- infinity. When there's nothing there, why should it be in a some sort of container or be limited in any other way (in a geographical sense)?

- suction. We know vacuum sucks. So...if we got a room full of vacuum and, let's say, a popcorn inside it, it will get bigger until it completely fills the room (in theory)

So, if you proposed the universe was "surrounded" by infinite vacuum, and if you know that even a small vacuum can suck 2 horses tightly together (i'm referring to this one vacuum-ball experiment here) you can imagine the tiny bit of gravity would just do nothing to hold the matter from spreading.

No need for Dark Matter / -Energy in this model. What's the reason you can't get around them?

Re:I don't get it

[Anonymous Coward]

There are a lot of problems with your theory. First, vacuum does not "suck" -- there is no attractive force that pulls things into vacuum. Rather, things expand into vacuum when they have internal pressure, and there is nothing to keep that pressure from making them expand outward.

We can measure the density and pressure of the universe, and the numbers just don't work out for your idea. More than that, your idea predicts that there is a boundary between matter-filled space and, outside it, empty vacuum. We do not have any evidence of such a boundary -- as far as we can tell, matter is distributed uniformly everywhere in the universe.

Re:would it have been so hard...

[Anonymous Coward]

Aw, you sound like you could use a nice nap and a warm cup of cocoa. Feel better?

Re:would it have been so hard...

[WTFmonkey]

I could use a hug, too.

Sure, whatever

[ArsSineArtificio]

This cold dead universe assumes that there will be no intelligent intervention. I am not talking about a mythical 'god' at all but more about advanced civilizations.

Because it makes so much more sense to hypothesize "advanced alien civilizations" than "a mythical 'god'".

Obligatory Star Wars reference

[Anonymous Coward]

Yes, an individual known as Vader shall tap into the dark energy.

You cannot fight me Obi-Wan

[Razor Blades are Not]

I guess this also answers the question of which side of the Force is the stronger.

3rd Option

[offhtehizzle]

fire and ice sounds good, but I gots a third option. how about the universe expands until the gravity gets all spread out evenly and it just stops and balances on the edge of choosing fire or ice for a good long time?

Re:What about support tiers?

[kleine18]

reality.sys must be corupt.

Re:would it have been so hard...

[gotscheme]

Well, actually, to get to the specific questions without having to remember the post id, it is ten more clicks.

PS. So you know Christ?
PPS. Who's Shit?
PPPS. Is "just because your big ass fatfingers mouse buttons is" legitimate English?
PPPPS. "burdgeon" is not a word.
PPPPPS. There was only one complaint in the post you replied to.

re: if we find..

[Razor Blades are Not]

And then there's this ship completely composed of Dark Matter sitting right there, when we arrive.

"Every time you try to operate on of these weird black controls that are labelled in black on a black background, a little black light lights up black to let you know you've done it. What is this? Some kind of galactic hyperhearse?"
- Zaphod Beeblebrox

Infinite Universe

[solarlux]

Is the concept of an infinite universe accepted by more cosmologists than not? I'm trying to think through how that idea would work. Is the term "infinite" referring to space? If so, then I assume it refers to mass/energy as well (based on the cosmological principle of homogeneity).

But wasn't the original material of the big bang a singularity? And doesn't singularity imply a finite (or essentially zero) amount of space? If not, then the singularity would need to be an infinitely "large" amount of space, which subsequently expanded. Thus, all of our visible universe would be but a speck amongst the "infinite singularity" that expanded/exploded. Is this how the "infinite universe" model works?

Re:Infinite Universe

[Anonymous Coward]

Is the concept of an infinite universe accepted by more cosmologists than not?

Spatially infinite and finite universes are equally well supported by the current data. If inflationary theory is correct, we will never be able to determine which it is, because the universe will be so much larger than the observable universe that we'll never be able to tell the difference between "infinite" and "really really large".

A singularity does not imply finite space. It implies infinite density. You can have an infinite space with a singularity of infinite density. In such a model, the universe is never finite.

Re:Infinite Universe

[oldtimer619]

Thanks to Charles Seife, I understand the following: "Actually, the term infinite actually refers to the extent of space. The initial singularity of the big bang can actually create an infinite chunk of spacetime -- in some scenarios, the singularity is mathematically equivalent to an event which happens everywhere on a pre-existing infinite sheet."

Re:Wait A Minute..

[Anonymous Coward]

I don't mind!

Sounds like.....

[reality-bytes]

Sounds like an attempt to define something which could quite possibly be infinite as being finite

Thats not to say it isn't worthwhile research; the Universe may very well be of finite existance, It just means that it is bloody difficult research.

Do we have concensus?

[khallow]

We're in the middle of a scientific revolution, in the honest-to-god paradigm-shift sense. This revolution started in 1997 when two groups of astronomers, the High-Z Supernova Search Team and the Supernova Cosmology Project used the bright flashes of a particular type of dying star (a type-Ia supernova) to measure the expansion of the universe at different times in the past. Since then, a whole raft of astronomical observations -- of faint patterns in the afterglow of the big bang, of distributions of galaxies, of the composition of intergalactic clouds of gas, of distortions of light going around massive bodies -- have all forced cosmologists into a remarkable consensus about the composition of the universe and, yes, its fate.

I think this statement is wrong. Perhaps, most cosmologists agree with the author (I don't know the truth of that), and there does seem to be a lot of people saying that the NASA survey which yielded the 13.7 +/- 0.1 Gy measurement of the age of the universe is probably "close" though perhaps not to the degree implied by the precision (the 0.1 Gy error bar).

However, the talk of anti-gravity (whatever it is) and other such things is just talk at this stage. All the experiments described don't measure anti-gravity directly. In particular, this means that the current variants of anti-gravity theory haven't been ruled out yet, not that they are "implied" by these experiments.

IMHO, we need to measure this "anti-gravity" effect directly. One interesting idea was that perhaps the gravitation constant as normally measured (by measuring the force of attraction between large weight using a Newtonian mechanics model) may vary at different places on the Earth's surface. Namely, a Chinese research center derived a different value for the constant than the one officially derived (somewhere in Europe I think?). An actual difference here would imply some sort of derivation from normal theory that probably would support the general category of theory.

Finally, I'm suspicious of the use of the phrase "anti-gravity". What does it mean to be "anti"-gravity? Is it always opposite or against gravity? Presumably, it's a cosmological phrase to indicate the deviation from a pure gravity attraction. And apparently always repulsive. But the force could be non-gravity related or even a "pseudo-force", an apparent force that is merely the result of using a flawed model on the actually situation and seeing something being pushed the wrong way. Ie, "anti-gravity force" is merely the difference between the forces we thought were acting on the object versus the forces actually acting on the object. It seems particularly wrong to label errors in our models as "anti-gravity", but isn't this what the author is advocating?

A pretty straightforward variant of these theories is Kaluza Klein theory (the 5-dimension case) which predicts a coupling between gravity and electromagnetism. It requires no quantum mechanics nor the existence of the Strong and Weak forces in order to make predictions about unusual perturbations in the force of gravity.

For example, the Earth's gravitational and magnetic fields would interact resulting in deviations in the measurements of the gravitational constant (the measurements would be using an incorrect model of gravity and hence using a slightly flawed calculation for the gravitation constant that would depend in part on the strength of the magnetic field). In particular, no "anti-gravity" force exists. We're dealing totally with gravity and electromagnetic forces.

Re:Do we have concensus?

[Anonymous Coward]

IMHO, we need to measure this "anti-gravity" effect directly. One interesting idea was that perhaps the gravitation constant as normally measured (by measuring the force of attraction between large weight using a Newtonian mechanics model) may vary at different places on the Earth's surface.

The "antigravity" effect being discussed here is not measurable on such small scales. We have to use cosmological observations to detect it.

For example, the Earth's gravitational and magnetic fields would interact resulting in deviations in the measurements of the gravitational constant (the measurements would be using an incorrect model of gravity and hence using a slightly flawed calculation for the gravitation constant that would depend in part on the strength of the magnetic field).

This effect is also not measurable, if you're talking about Kaluza-Klein theory. In this case, deviations are only detectable on extremely small scales. We can't probe gravitational effects smaller than ~millimeter distances right now, nowhere near small enough unless the "large extra dimensions" variants are true. (Most people believe the compactification scale is much smaller though.)

Re:Do we have concensus?

[khallow]

This effect is also not measurable, if you're talking about Kaluza-Klein theory. In this case, deviations are only detectable on extremely small scales. We can't probe gravitational effects smaller than ~millimeter distances right now, nowhere near small enough unless the "large extra dimensions" variants are true. (Most people believe the compactification scale is much smaller though.)

One of my problems here is determining what has been ruled out so far. What experiments have been done to rule out large compactification scale? Eg, has observation of magnetars or other situations with both strong gravitational and electromagnetic fields ruled out certain scale ranges on any models? Thanks.

Agreed

[Jack9]

Best-longest interview. I congratualate Charles and Slashdot.

Impact of Godel's theorem

[Stuntmonkey]

...for example, I think that Godel's incompleteness theorem hasn't changed society in the slightest.

Yes it has. It means that nobody can ever make a compiler that spots runtime errors. Software would be considerably less buggy were this not so, and I'm guessing that a majority of individuals in modern society have been directly or indirectly affected by software bugs.

Re:The future is now

[coryboehne]

(And if Microsoft built the universe, a reboot would be coming sooner rather than later. *duck*)

Anyone else catch this?

I don't know about his predictions, although I do tend to trust them, mostly because he sounds damn confident and well informed, but also because of the above comment for the following reasons,

(1.)Anyone who makes jokes about Microsoft's weaknesses is instantly liked by me.

(2.)It is obvious he is not a regular slashdot reader, hence the *duck* at the end of that statement, if he were a /. regular he would have realized that was entirely unnecessary...

Now let's do some conjecture for fun..

Given: Anyone who reads slashdot is highly unlikely to get anything done on a regular basis.

Given: He does not read slashdot on a regular basis.

Conclusion: His information is probably trustworthy, highly accurate and +5 informative.. ;)

--

Although other than that silly observation I must say this was really informative and fun to read, I just hope that I live another 80 years to see the advancement we've made by that point in this and other scientific fields, we are moving forward today at such a breakneck pace it's truely amazing, and if we were to continue at the same pace for the next century the advancements should be really amazing. And a big thanks is owed for the wonderfully explanitive and through responses, rather than the usually I-don't-have-time-for-this/bland responses that the interviews tend to generate..

could we capture and use dark energy?

[the_2nd_coming]

if we could use dark energy to create normal energy for our uses, that could be such a large pool of free energy that for our species, it would be infinite.

and if dark energy is used to speed the expansionof the universe by creating an anti-gravity force, this would allow us to make anti-gravity a power source for space flight!!! amking inter stellar travel possable!!!

I am definatly buying this dudes book!!

Wormholes?

[kurtkilgor]

The way wormholes are supposed to work is that they provide a shortcut through (n>3)-dimensional space around a bend in 3-space. But if the universe is flat, does that mean that wormholes would be useless?

remember the 2nd Law of thermodynamics

[kneels_bore]

Unfortunately, even the most intelligent civilisations will ultimately run out of energy in the cold dark end point of the universe. No way 'round the old 2nd law. All the food in the Restaurant will be served ice-cold.

The best

[Anonymous Coward]

The best article I've seen on Slashdot in ages. Thank you.

Big bang violates COE?

[argoff]

It would seem to me that a big-bang that comes out of nowhere would be the ultimate violaion of the conservation of energy principle? If not, then what the heck could have been going on before the big-bang?

Re:Big bang violates COE?

[Anonymous Coward]

The Big Bang only violates conservation of energy if the universe was at one time empty, and then all of a sudden matter appeared inside of it. But there aren't really any models like that. In most models, either the Big Bang was the beginning of time -- so matter was present starting from the first instant of time, and there was no earlier time when an empty universe existed -- or the universe is eternal (and the Big Bang is just a special event that happened at a particular stage in its development).

rebirth?

[Shwag]

"There are restrictions on this rebirth argument, though. For one thing, the fact that the universe will expand forever prevents a big crunch in our future, so we're at the end of the line if such a line existed."

But I think I remember Stephen Hawkings saying something like ... A infinitely expanded and infinitely flat universe is relatively speaking, exactly the same thing as an infintesmal.

Hence, no contraction, but you get another big bang.

Re: Black holes don't exist

[andersa]

Not the black holes you are thinking of at least.

The classical black hole is very simple. It has an event horizon with a singularity inside. You need just three properties to fully describe it; mass, angular momentum and electric charge. In fact you will almost certainly only need two of those, since if a black hole was charged, it would quickly suck in opposide charge, thereby making it electrically neutral.

The problem is that this description doesn't take quantum mechanics into consideration. A number of basic premises of QM renders the black hole model less than likely. Heisenbergs uncertainty principle states that you cannot possibly know the position and impulse of a particle simultaneously with 100% accuracy. If you limit the singularitys position to the volume inside the event horizon, the random impulse would give it a tiny chance that it would move outside the event horizon and thus revealing a naked singularity in normal space. That's bad.

In reality that description doesn't even hold water. To really understand what a black hole is you would need to combine general relativity with quantum mechanics, and make the theory of quantum gravity. This is something that hasn't been done yet, though some toy theories do seem somewhat promising.

If you asked me I would tell you subj. Black holes don't exist. The compact objects you find around the universe are probably some really exotic things like maybe grava stars.

In any case since it is probably not possible to create a classical black hole, there is need to worry about how the universe managed to escape that destiny. The same quantum effect that prevents black holes from forming, probably also prevented the early universe from meeting an early doom.

Re: Black holes don't exist

[Anonymous Coward]

Oh good grief. "Gravastars" are even more exotic than black holes are: black holes can form under quite realistic circumstances using conservative laws of physics. Nobody has proposed any kind of remotely plausible mechanism by which gravistars can form in any kind of astrophysical process. Sure, they may be solutions of the field equations, but you can cook up all kinds of implausible solutions to the field equations. The question is, which solutions are realistic? Thanks to the GR theorems of the 1960's, we know that black holes can form under very generic circumstances.

And by the way, no, quantum effects do not prevent black holes from forming. They might have an influence on whether a black hole singularity forms, though.

Re:What about support tiers?

[Rolo Tomasi]

It was me. I did it.

Re:Agreed. Now how about...

[Jason_says]

In Soviet Russia: 3. Profit!

2. ???

1. Imagine a Beowulf cluster of sigs, you insensitive clodingenious? i think so

Re:The future is now

[Anonymous Coward]

You seem to hate Microsoft so I'll assume you are a linux user. What are you going to do in 6 months when Linux requires an SCO licence? You're parents won't pay for it. Well, I think at that point you'll have to have sex with men for money on the street, but that's ok because you already do it for free.

Re:The future is now

[coryboehne]

Ok moderators / sensitive slashbots, I'll apologise in advance for even responding to this, but it's rare a troll provides such a good opportunity to make them look dumb,dumb,dumb(more so than they already do for themselves...). And yes I know this is terribly OT, but considering the article is already a day old I doubt that anyone is really going to mind a bit more noise in the ratio..

Please regard the following response as a joke, or if you are really humor impared, simply regard it as a form of correctional material that was most sorely needed.

Posted by Anonymous Coward on Friday August 08, @11:45PM
You seem to hate Microsoft so I'll assume you are a linux user. What are you going to do in 6 months when Linux requires an SCO licence? You're parents won't pay for it. Well, I think at that point you'll have to have sex with men for money on the street, but that's ok because you already do it for free.


Ahh, but what do we already know about assumptions?? :)

You've just found out about Murphy's law, take heed dear troll, as you certainly have ample opportunity to learn here..

I am a .NET developer, as such I do find great humor in anti-Microsoft comments, especially the ones that are right on target, however I am most definately not a Microsoft Hater.

Am I a Linux user? Yep.. However, I've never used the 2.4 or later kernel, so guess what? I'm exempt from SCO's little extortion scheme.

And, as for your last assumption that wasn't just a flame. I don't live with or rely on my parents for money, sorry to disappoint you yet again..

Geez, I guess that's three so far.. But wait! There's more!!

As for your flame, I'm not sure about this, but you, dearest troll, have assumed that either (a) I'm female because I have the name Cory OR (b) I am going to be really hurt that somebody would insinuate that I am gay. As you may have guessed, I'm not a girl, and well frankly, I'm not gay either, however I've always been amused when people actually ask me if I am... ("No I'm _not_ gay, but thank you for asking"...... :) ). And for crying out loud, just because you have to pay for sex doesn't mean everyone does.. LOL!

So, what have you now learned here dear troll? Hopefully that Murphy's law can hold quite true, you have made no less than four assumptions that were exactly 180 degrees off, that is to say they couldn't have been more wrong if you had tried.. However, I will be glad to advise you on several techniques that you may find useful in the future when flaming me:

(1). Always look at a users last few posts by visiting their profile, if you're really wanting to dig use the search feature.. This can provide valuable knowledge about who/what a user is and what might actually be a safe assumption and what might anger them.

(2). When trolling try to pick on people who tend to end up with a lot of -1 comments due to their tempers and quick knee-jerk responses. These people are generally good targets for your childish behavior.

(3). Whatever you do, should you see a post from a user named:
(a) Micheal
(b) CmdrTaco
(c) CowboyNeal
Flame these users heavily, as they will surely provide a most dramatic response to your troll-posts.

(4). Should you ever run across one of my posts again, and feel like flaming me, please by all means flame away.. I almost regard it as an integral part of the slashdot experience, however using the above #1 and #2 may prove most valueable to you in your quest for good trolling material next time, and will keep you from looking like such an idiot.

Cheers,
CoryBoehne

Good story

[danny256]

I liked that one.

I knew they had it all along!!!

[diablobsb]

They're what Hubble used to spot the expansion of the universe in the 1920s, but they're relatively dim and impossible to find in very distant galaxies.

aha! I knew they had Hubble all along...
This is an alien artifact, not a satellite!

Time to get my tinfoil back....
brb...

Re: Black holes don't exist

[andersa]

Well I wouldn't even call a black hole exotic. It's as boring as it could possibly be.

Let's just agree on exactly what kind of an object we are talking about here. A black hole is as I described above a simple event horizon, which is only a mathematical edge, and the singularity at the center (if it's spinning it's a ring).

As you say quantum effects could prevent the singularity from forming. I argue that if you don't have a singularity, you don't have a black hole. I am not saying you couldn't have something that looks and acts similarly though.

Anyway the original question was why a universe which was so dense, didn't collapse into a black hole. And probably the real reason why it wouldn't do that is that all the matter in the universe at that point was evenly distributed. That means that the gravity field lines locally are completely straight. To create a singularity you need the worldlines to be extremely curved.

And then there is the whole inflation issue..

bizarro-you on bizarro-earth

[Anonymous Coward]

So somewhere in the in the birarro world the bizarro-me could actually have sex?

Mind blowing!

the universe is a pretty cool place.

[Lispy]

Yup, it the coolest place to be...

The Ultimate Problem...

[Rob_lo_Tek]

The Ultimate Problem for a continuous working Universe. Perhaps our destiny would be a sort reverse-entropy from the lessons we learn converting energy & matter. Always the Optimist ;-)

Re: Black holes don't exist

[Anonymous Coward]

As you say quantum effects could prevent the singularity from forming. I argue that if you don't have a singularity, you don't have a black hole.

Gravitational physicists define a black hole to be the region of space enclosed within an event horizon. If quantum gravity removes the singularity, they would still call it a black hole.

Anyway the original question was why a universe which was so dense, didn't collapse into a black hole. And probably the real reason why it wouldn't do that is that all the matter in the universe at that point was evenly distributed. That means that the gravity field lines locally are completely straight. To create a singularity you need the worldlines to be extremely curved.

There are so many things wrong with that paragraph...

1. There isn't any such thing as a gravitational field line in general relativity. Field lines are the integral curves of the gradient of a potential, and unlike Newtonian gravity, gravity in general relativity is not simple enough to be described in terms of a potential. Or, from another perspective, it can't be described in terms of a vector force-field theory. It's a tensor theory.

2. Likewise, there's no requirement in GR for "worldlines to be extremely curved" for a singularity to form. (And did you mean worldlines, or field lines? Worldlines of cosmological matter are indeed straight -- in spacetime -- but that doesn't prevent a singularity from forming when they all converge on each other in space.)

3. There's no reason why an even distribution of matter can't collapse into a black hole and form a singularity. There are many simple models of black hole formation that do just that.

The reason why the universe didn't collapse into a black hole is there's no reason why it should. It simply isn't true that any dense collection of matter must collapse into a black hole.

Infinite Universe

[oldtimer619]

Putting aside the multiverse for a moment, some clarification may be necessary re. the term "infinite" used for this one. Given that the big bang was the beginning of time and space as well as matter and energy, and that space has been expanding at a finite rate, then doesn't the term "infinite" refer only to the mathematical curvature (open)? The size of space itself must be some 40B light-years (more that ~13B light years since the space is expanding). Please clarify. Thanks.

Re:What are we playing jeapordy now?

[Anonymous Coward]

Stop eating my turds you sick fuck.

Zero, Gateway to infinite Realities

[The26thDimension]

I read the story, and when i came across ZERO, it reminded me of a notebook i wrote when i was in 10th grade high school, nearly 200 pages long. I have the book "ZERO". The book sparked my interest in imaginary numbers, but later led my interests into things far beyond what my own brain could handle. first i was curious about the square root of imaginary, and the square root of that, and so on.. until basicaly we're saying Something to the power of zero. i thot it would no longer be a value of any charge, but rather a neutral charge, not positive, not negative, not zero, but neutral. I thot of it to be another Zero, much like zero it'self, but a zero of higher order,. then i thot about an infinity of higher order. Eventually, i almost successfully mapped out the pattern of all symmetry, and i realized there were infinite orders, and infinite sets of those orders,. and there seemed to be possibilities of realities of higher orders and of lower orders, lower orders below that of numbers and charges, or orders lower than dimension(direction) or magnitude, still consisting of value, but not able to be defined by any known algebraic mean. Infinite realities "less real" than our own, and infinite realities "more real" than our own. Yet we are subject to those "lower" realities and to those "higher" realities. But the key to all of it, is within a single singularity, zero!, yet just zero alone already "contains" infinite "tunnels" to far out realities even beyond infinity. Our entire universe can be just a singularity containing infinite possibilities, yet all following simple pattern saying that all equals each other, all is within one point. This brings up a thot i once had, that a blackhole might look like it "dips" into a point where everything is crushed, but that's just from our point of view(ourside the blackhole), but at that singularity of the blackhole actually lies infinite realities. It's like a wormhole to other universes, but yet all equally real to our own also containing blackholes. You might think of the blackholes to be as gateways to either lower or higher sets of realities, and that we ourselves might be contained within one blackhole of a higher reality. I make this sound like we're living in endless Hell. But, this whole idea was born from some math thing i was doing, however, in the end i closed my book and wrote the final conclusion "Anything and Everything is possible, and exists somewhere"--be it just in our minds, which i'm also trying to impress that our minds are just as real as the universe we're in, it's just at a lower or higher order of reality than our own.