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NASA: Evidence Favors Infinitely Expanding Universe
Chris Gondek writes "The Sydney Morning Herald has a story here about how NASA is expected to announce this week that it has proved the existence of "dark energy," a cosmic force that counteracts gravity and will keep the universe expanding forever. The announcement will effectively demolish the theory that life will be wiped out in a "big crunch" when the universe collapses, and should end decades of academic dispute. Scientists ranging from Stephen Hawking, the Cambridge University physicist, to Albert Einstein, have argued that the universe eventually will stop expanding and then implode under the force of gravity, destroying all life. The Chicago Sun Times has also got some info."
but my money is on Hawking and Einstein, and not only because they had a handle on the metric system.
Dammit. Now I'm going to be able to feel my atoms growing farther apart all week.
So the universe won't be wiped out by a big crunch.
What a relief. I was worried.
The universe will be wiped out by the heat death of the universe instead.
(Or am I incorrect in my understanding?)
The price of freedom is eternal litigation.
So all that money that I spent on "Big Crunch" insurance is going to waste?
-Valiss
So instead of the Big Crunch, we get Heat Death. The universe is slowly cooling, and will eventually cool to absolute zero (killing all life), or so the theory goes.
I don't think that there is any reputable theory that doesn't have a "killing all life" at some point in the very distant future.
What will remain is a universe full of black holes, which after trillions of years will explode to leave nothing but dark energy.
This is true... unless there is another mechanism that transforms some of the dark energy back to normal matter. This could result in a classic steady state model.
Well, I'm no astophysicist, but won't this new theory disprove all previous theories about the Bing Bang as well, and everything we thing of the Universe thus far. If this susbstance will keep the Universe expanding forever, how was it ever possible to have a Big Bang in the first place? It would be inconcievable to think anything created the Universe in the Big Bang theory, because it could never happen, thus our Universe does not go in cycles (expand then contract - repeat).
So, How did the universe get created. Does this mean that there was actually a "beginning of time" as far as we can tell? What was that point? What existed before then? Since matter can't be created nor destroyed, where did it come from? (though that is a question beyond most planes of though, IMO)
I don't believe this story, and I think more research is needed here.
"Time is long and life is short, so begin to live while you still can." -EV
You got it, though "wiped out" isn't really the term I'd use (more like "stretched out"). It lowers the heat death temperature so that it approaches absolute zero, since the space occupied would constantly expand. Also, it's a rather lonely future even before then, as galaxies grow so far apart that you eventually can't see anything but your own big front yard.
I wouldn't get too excited, though. There are virtually no "facts" in cosmology that haven't been overthrown multiple times. This one will be no different.
I'm watching for coverage of the actual event in the Chicago White Dwarf Times.
If tits were wings it'd be flying around.
Some say the world will end in fire,
Some say in ice.
From what I've tasted of desire
I hold with those who favor fire.
But if it had to perish twice,
I think I know enough of hate
To say that for destruction ice
Is also great
And would suffice.
Why? It's just as good a term as Einstein's cosmological constant. It's just a label.
And the "blackbox" approach is part of figuring out what is going on. We don't know how gravity works. Does that stop us from knowing that it does work, or what effects it has on the universe? This is no different.
If we had to wait until we had a nuts-and-bolts answer for every question we'd never get anywhere.
Boobies never hurt anyone. - Sherry Glaser.
> Whew! That's a relief!
Reminds me of the story of the student of cosmology who frantically waved his hand until the annoyed professor finally called on him.
"Professor, would you mind repeating what you just said about the end of the universe?"
"I said that according to recent estimates it would take place in about 200 billion years."
"Oh, thank God, you really had me worried there for a minute! I though you said million!
According to the best cosmological theory we have now:
The universe came into being. At first, there was but one force. As the universe grew larger and colder, aspects of that one force that were hidden became apparent - these are the forces we know of now: gravity, electroweak, strong nuclear.
Consider:
Trillions of years from now, the universe is much larger and colder. Aspects of the four forces we know of now become apparent, creating new forces.
Who is to say that in a google of years, there won't be some lifeform that will look back and say (translating to English) "We aren't sure what happened in the first trillion years, but after that, the 27 forces of nature we know of began to manefest themselves..."
Who is to say that there was not some lifeform living at the first 10e-32 second that was looking forward and saying (translating into English) "One day, seconds from now, all life as we know it will cease, and the universe will be far too cold to support life."
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How the hell can they predict what the universe is going to do in trillions of years, but I can't get an accurate weather forcast for the next 24 hours??
Buy the President
The assumption is that the laws of physics are uniform throughout the universe, which I also assume to be true. However, I don't assume that gravity is an attractive force, but rather one that obeys common sense, and is repulsive in nature at the quantum level.
I believe that when a graviton interacts with a particle, it pushes it along... just like any other particle interaction... but I believe that the source of the gravitons is external... and that each interaction creates a shadow... thus there would be slightly more gravitons coming at be from above, than have managed to pass through the earth to hit me from below... thus creating an apparent (and real) local gravity field, with the deficit in the downward direction.
The experiments to prove this are going to be very sneaky... but one sure proof would be that a material that stops gravitons would be very heavy, instead of having a negative weight. Even if you managed to stop some of the gravitons... then effects would be on the opposite side of the device than expected. Thus if your anti-gravity plate is put underneath a weight, it would actually get heavier... and if you put it above the plate, then it would get lighter.
The truely interesting effects occur when you get black-hole level matter density. If I'm right... then they should probably "boil off" slowly as some of the matter gets pushed out of the hole over time.
--Mike--
My guess is that they are talking about the results from MAP. This is a satellite that was looking at the CMB. Unfortunately, this won't tell us one bit about dark energy. What it tells us about is the total matter-energy budget of the universe. But we've known that the universe is "flat" since COBE (the last satellite to look at the CMB).
The basic way at looking at cosmological parameters is this: CMB tells us about the geometry of the universe (Omega_total = Omega_matter + Omega_energy), clustering tells us about the matter content (Omega_matter), and supernovae tell us about the acceleration of the universe (Omega_matter - Omega_energy).
Only supernovae have given us direct evidence that the universe is accelerating.
It's kind of a funny term. Heat death is actually the complete conversion of all the free energy in a system (in this case, of all systems) into the corresponding entropy. It's the victory of the second law of thermodynamics. It's not that all the energy goes away, but that it becomes so evenly spread that no further work is possible - there are no more free energy gradients to traverse. So it's not the death of heat, it's a death in heat - literally a tepid cosmos. ;)
As I noted in another message, an infinitely expanding universe means that the temperature of the heat-dead cosmos will constantly drop as the volume increases. It will asymptotically approach absolute zero.
Some others have noted that there are theories where energy and/or matter are spontaneously created in empty space. These can coexist with the heat death fate if the new energy is also evenly spread, which it probably would be in such a uniformly boring heat-dead universe. Still no way to create a new free energy gradient.
I find this an interesting fate because it's also reflected in some religions and philosophies, where everything becomes one at the end of time.
Also remember that no one has been looking to see if energy is added or removed from the universe. All of these theories are based on the notion of a closed system. What if that assumption was not true?
"Learning is not compulsory... neither is survival."
--Dr.W.Edwards Deming
NASA definitely will not announce that they had proven the existence of "dark energy"; all they can really announce is that data they collected suggests an infinitely expanding universe. (This would not, btw, require dark energy, though an accelerating universe might; all it would require would be for the total matter and energy in the universe to be below a certain threshold level.)
I don't really know a whole lot about "dark energy" at this point... a few mentions here and there have given me a murky idea of it as similar to Einstein's cosmological constant, but nothing really definitive. Some recent evidence does, I believe, suggest an accelerating expansion which could lend credence to the theory... but I believe there have been alternative hypotheses advanced as well.
I am not a physicist, however, merely a freshman physics major. ;-) I know the NASA announcement isn't out yet so primary sources on this particular experiment are hard to come by, but can anyone suggest some background or current research on dark energy and the cosmological constant? My only real source so far has been Scientific American--that is to say, I've got no reliable sources. [grimace]
Much appreciated....
"Science is a way of trying not to fool yourself." -Richard Feynman
Are you talking about how there is no global energy conservation due to time assymetry and Noether's theorem?
I find this an interesting fate because it's also reflected in some religions and philosophies, where everything becomes one at the end of time.
Don't most religions postulating "one" at the end of time actually have something closer to the big-bang / big-crunch? I mean the final conflagration in Heraclitus on up through the Stoics seems to have much more in common with the earlier view of cosmology. The big cruch returns everything to fire = logos that was had at the beginning of the universe. In this view the fire is raw energy and information.
I don't know of anything in traditional philosophies or religions that really corresponds to the heat death of the universe.
Is it called the "Bing Bang" or the "Big Band"?
Halton Arp, an award winning astronomer who used to be Edwin Hubble's assistant, has spent years documenting physically connected astronomical bodies with vastly different redshifts. That's simply impossible under the current theories. But they exist.
He's published several books on the subject including Seeing Red: Redshifts, Cosmology and Academic Science which presents considerable information that's been surpressed by astronomers whose theories have been threatened.
In Seeing Red, he also lays out an alternate, simplified theory, which is a _slight_ modification of the general theory of relativity that ends up predicting the real world observations without resorting to magic constants, curved space, "dark matter", and other kludges that the currently accepted theories need.
Here's some other info about it.
I think that Buddhist Nirvana sort of does; entities that become enlightened are never returned to the wheel of life, so there's a constant drain of energy "lost" by the world to nothingness. The peace of Nirvana always seemed something like a perfectly uniform universe to me. Eventually everyone on every plane is enlightened and everything is just sort of frozen (which is a way of looking at heat death, complete equilibrium being equivalent to no motion at all).
On the other hand Taoism would propose a universe that expands back into the original version of itself, since everything proceeds through an extreme, into and through its opposite, and back into itself. That's broad enough that you could fit either a big-bang-big-crunch, or a heat death where something about the uniform state causes the return of extreme nonuniformity (which is entirely possible, see below).
One of the things I find provocative about the heat death and "big egg" fates is that they're at some level indistinguishable. Once the universe is uniform, both time and space becomes meaningless, just as they do after a big crunch. So the Taoist view makes sense to me - the universe really does find its opposite (and a rebirth) at the extreme ends of time.
Oh well. I really have things I should be doing today besides discussing cosmology, if I'm to be able to afford to keep converting free energy myself. ;)
Even if we don't live in a closed, oscillating Universe, it's still possible that the Universe could "reboot" itself after the heat death. [Disclaimer: complete speculation follows. I am an astronomer, but by no means am I a cosmologist]
If we live in a non-oscillatory universe, then the Big Bang was not a "bounce" due to a preceeding Big Crunch. Rather, the Big Bang arose from a quantum fluctuation in the vast nothingness that was (or was not?) before. So, if the Universe of the very distant future has expanded to ~zero density and ~zero temperature, then it looks basically just like the pre-Big Bang vacuum. In that case, another Universe might very well pop up from another quantum fluctuation in the vacuum.
Hell, who knows? Maybe a sufficiently empty vacuum is extremely unstable to such Universe-spawning fluctuations, so they are pretty much certain to occur once the density and temperature get low enough. If so, there you go: we can have our heat death and still have Universal rebirth.
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This is the way the world ends
This is the way the world ends
This is the way the world ends
Not with a bang but a whimper.
from "The Hollow Men", TS Eliot.
Attribute your sources!
--Jim
The rate of expansion IS decreasing, the question is will that be enough to cause the crunsh or not because the rate of decrease (second derivitie of velocity) is decreasing as well.
That's the old (early 90's) model. Before the supernova data, we thought that the universe would be decelerating. However, now we're pretty sure that the universe is accelerating, not decelerating.
However, that doesn't mean that the universe won't decelerate later (or didn't decelerate earlier). There are still a lot of questions as to what the dark energy is and all of the accelerating/decelerating depends on what it is.
Google for quintessence. It's beyond my area of expertise.
Regardless of what the dark energy actually is, the universe is accelerating right now.