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How Big Was the Universe When It Was First Born?
StartsWithABang writes: Looking out at the distant stars, galaxies and radiation in the Universe today, we've been able to determine not only what it's made out of, but how long it's been since the Big Bang: 13.8 billion years. Put all that information together, and you can also figure out how large the observable part of that Universe is today. From our point of view, it appears to extend for 46.1 billion light years in all directions. So what if you extrapolate backwards, to the very end of inflation and the start of the hot, dense state we identify with the Big Bang, and ask how large that 46.1 billion light year "size" was back then? How big would it be? Depending on the particulars of when inflation came to an end, the answer is somewhere between the size of a soccer ball and the size of a city block, no smaller and no larger.
Can't read TFA. Does anyone got a link to an article that isn't behind an anti-adblock page?
IInformation wants to be free. It's part of cosmic entropy.
In the end we will figure out that someone divided by zero and the universe accidentally came to be.
If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
you're no better or more accurate than religious beliefs.
They definitely are.
Note that this is only talking about the portion of the original the universe that became today's observable universe. There's absolutely no reason to believe that the size of the observable universe is the size of the total universe (and we happen to be at the very dead center of it.)
There is good reason to believe that the universe is far far larger than the observable universe, and it may even extend infinitely in all directions, for all we know. Measurements on the curvature of the universe make that a plausibility.
Please slashdot, please let us block posts by submitter not just by editor. PLEASE. This shit is becoming unbearable.
I could be very wrong, but nothing can travel *through* space faster than light. That does not stop space expanding faster than light.
Looking out at the distant stars, galaxies and radiation in the Universe today, we've been able to determine not only what it's made out of, but how long it's been since the Big Bang: 13.8 billion years.
Umm, not so much.
Might want to check out other theories like ones that incorporate quantum theories.
http://phys.org/news/2015-02-b...
"(Phys.org) - The universe may have existed forever, according to a new model that applies quantum correction terms to complement Einstein's theory of general relativity. The model may also account for dark matter and dark energy, resolving multiple problems at once.
The widely accepted age of the universe, as estimated by general relativity, is 13.8 billion years. In the beginning, everything in existence is thought to have occupied a single infinitely dense point, or singularity. Only after this point began to expand in a "Big Bang" did the universe officially begin.
Although the Big Bang singularity arises directly and unavoidably from the mathematics of general relativity, some scientists see it as problematic because the math can explain only what happened immediately afterâ"not at or beforeâ"the singularity.
"The Big Bang singularity is the most serious problem of general relativity because the laws of physics appear to break down there," Ahmed Farag Ali at Benha University and the Zewail City of Science and Technology, both in Egypt, told Phys.org."
Strat
Progressivism (aka US 'Liberalism'): Ideas so good they need a police/surveillance-state to enforce.
I could be very wrong.
You're not. The idea for the Alcubierre drive is based upon this principle. No known law of physics contradicts space-time from expanding at any rate. You only need tremendous amounts of power to reach this result.
Religous speak to God. Insane are spoken to by God. When all shut up, one can finally hear Shostakovich in peace
If you have a lot of mass in a small enough space, the gravitational pull of the mass creates a black hole. If all the "stuff" in the universe was in such a small space, then how do you get an expanding universe? You should have a black hole from which nothing will ever escape.
Why would our universe be special? Who is to say that "our" universe it not the only universe? And, in that case, special compared to what?
Surely if all 'size' was in there, it was as 'big' as it is. The metric was changing then, just as it is changing now.
Why would our universe be special? Who is to say that "our" universe it not the only universe? And, in that case, special compared to what?
This universe? There's about 3.6 billion people (2 billion Christians, 1.6 billion Muslims and a few Jews) that think all of Creation revolves around this planet and the human race, at least according to Genesis. We could start with the idea that Earth and humans aren't all that special first, before moving on to this universe maybe not being the center of the multiverse.
Live today, because you never know what tomorrow brings
Why the fuck would you fiucking bother? Fuck fuckity fuck fuck fuck.
systemd is Roko's Basilisk.
Science does not know everything.
Religion does not know anything.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
Or just a single, ball shaped jewel in a pendant around a neck of a cat.
Because yes, you cannot move in space faster than the speed of light, but space itself expanding faster than the speed of light does not break that law. That is, admittedly, not easy to grasp and frankly I doubt that I have enough of a grasp of it to explain it sensibly.
The problem starts with all the shows that "show" you the big bang in some artist rendition: From the outside. There is no outside to the big bang as far as we are concerned because everything we know about is inside of what the big bang started. Think of it as sitting inside of a balloon that slowly gets inflated. You can move inside the balloon, with the balloon itself not moving but expanding.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
Oddly all I had to do is be persistent and click "yeah, ok, lemme in" enough times.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
Who cares? Enter the relevant search string into Google and find another page that gives you the information. Forbes is usually just barfing what others have fed it, adding a dash of spin and a truckload of ads, both you can easily do without.
Dear content providers, if you want me to disable adblockers, all you accomplish is to turn me away. There is rarely, if ever, content only available from one source. All you accomplish is that I get my information from someone else and you don't get to add your spin to the story.
tl;dr: Fuck you. NEXT!
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
Allow me to link to the non-Forbes, non-ad-infested, non-ad-blocker-blocking version of the article: http://scienceblogs.com/starts...
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
We could start with the idea that Earth and humans aren't all that special first
I did not state or imply that either the Earth or humans are special.
... before moving on to this universe maybe not being the center of the multiverse.
What multiverse? If you read what I wrote, I said: "Who is to say that "our" universe it not the only universe?" and then asked that if there was only one universe (ours) then there is nothing to compare it against and, therefore, there is nothing to compare our universe with to classify our universe as special or not special.
If you are stating that a mutiverse is an established scientific theory or law then I must have missed the paper. As far as I know the multiverse hypothesis isn't even testable and therefore not science; it's more akin to blind faith or religion.
The more important question, of course, is not "how big was the universe when it was first born," but "what gave birth to the universe?"
Love sees no species.
Mass doesn't warp space-time, energy does. Matter just so happens to have a lot of energy locked away in it.
How the fuck are the cocksucker shitstains at Forbes detecting that I am running AdBlocker, and how can the motherfucking logic be defeated?
This^ is the reason for all the Ethan/Forbes hate, narcissistic nerds absolutely hate somebody who can slam the door shut on their hand crafted, ad-free, browser. Especially when that "somebody" is the marketing department of a mainstream financial rag.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
To me, expansion is more imaginable if i imagine the `reverse` view:
"The size of the universe is 1 (just mathematical 1). At time of the big bang, and now, and ever. Matter (and all galaxies etc) 'shrink'."
Well, matter not actually shrinks and there's good theory to prove/assume that much, but as concept of imagining expansion, this approach works just fine for me.
A glitch a day keeps the bugs away.
I'm not sure you're really particularly familiar with your subject matter.
No-one serious (not: I do not cound Ethan as "serious" because his articles are pissing me off enormously) states that "The Big Bang" created the "one" universe and all of spacetime, nor that it "only happens once". The "big bang" is a loose term that merely states that the universe, back as far as we can observe, is well-modelled by a Friedmann-Lemaitre-Robertson-Walker metric. The theory does not even begin to address beginnings, since the very question is meaningless within its confines - there can be no "before" if time itself is meaningless at the "start point". Fortunately, no-one actually expects the model to hold before some very early time, since the theory of gravity we possess is expected to break down for high energies. That early time could be taken to be around a Planck time; realistically, the "big bang" could be taken to hold from around the time of the decoupling of the electroweak from the strong forces. From then on, the physics is well understood and the model is highly accurate.
This isn't to say that the question isn't addressed - merely that it cannot and is never addressed from within the FLRW model itself. Common solutions include various bouncing cosmologies (whether set up in the bounds of GR or one of its many generalisations and extensions), or smearing out that problematic singularity with quantum gravities (such as loop quantum cosmology) etc.
As for inflation being "one magic thing" that is "never to appear again", the classical inflationary theory involves a single slowly-rolling scalar field. The conditions are such that unless the universe reaches those energy levels again, the field has decayed into radiation and matter and is inactive. If you have issues with that, take them up with particle physics. But the concept - indeed the physics - is also often used to motivate so-called quintessence, or chameleon, or Galileon, etc. models, which can be used to produce the current observed acceleration of the universe.
Also, it's not really a "magic thing" in the first place. Slowly rolling scalar fields are ten a penny in the early universe, and are relatively straightforward to produce from UV completions of later-universe particle physics. And besides, natural extensions to GR, adding minimal corrections to its fundamental nature that are effectively terms in a Taylor series, cleanly produce an early-universe inflation which still remains our most-favoured model (though its competitors are less than one standard deviation off so I wouldn't take that claim more strongly than it deserves - though it has a theoretical bias towards it given its simplicity).
A flawed model? Quite possibly. Indeed, very probably. No-one working in the field would pretend otherwise. Otherwise they'd have concluded it was finished and be working elsewhere in physics and astronomy, wouldn't they? But it's hardly a collection of vague assertions backed up by masturbation.
I'm once more inclined to wonder why people think that a couple of minutes' of reflection will poke a massive hole in a theory that has been studied, at excruciating depth, by tens of thousands of people who trained for seven or eight years just to be able to begin to perform research in it. The arrogance involved in thinking that somehow one of these tens of thousands of people hasn't already seen the issue, and then spent months or years of intensive effort investigating its impact, is distressingly impressive.
Our universe was a soccer ball sized weapon stored in a missile rack on one of the star cruisers of the high masters. It was fired at an enemy installation during the ieter-universal wars. Our universe is just the debris field that occurred after detonation.
There is no God, and Dirac is his prophet.
As the light travels from the furtherest points from the oberver (at the speed of light), the universe is expanding at a similar rate. Say the universe expands by 10% over a year. Then light has to travel an extra 1 light year for every distance covered by 10 light years. But that expansion is like compound interest. In the next year, that distance covered by 11 light years expands to 12.1 light years. More time is spent traveling across expanded space that the original space that existed when the light photons first started out.
Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
At the point it was all crammed into that tiny space, it wasn't even regular matter than we know. It would have been one giant tangle-ball of sub-sub-atomic particles like quarks and gluons. No protons, neutrons or electrons.
Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
Whoever published it must have quite a pair of brass balls.
Yes, and they're each somewhere between the size of a soccer ball and a city block.
Size of a football for us that aren't North American.
Same.
An association football ("soccer") ball is 22-23 cm in diameter
An American football ball is 28 cm from tip to tip on the long axis, and 18 cm in diameter.
This article is about order of magnitude, and these two numbers are identical to well within order of magnitude.
http://www.football-bible.com/...
http://www.livestrong.com/arti...
http://www.geoffreylandis.com
Woot? How are over 40 billion light years observable when the universe is not even 14 billion years old?
That's a very tricky question. The answer is, the "observable" universe size as usually discussed in popular press means how far away is the most distant feature we could possibly see now. Definitions of "now" and "distance" depend on defining a frame of reference. For this, we pick the Earth as a frame of reference, but notice that for most of its existence, the photon was very distant from Earth.
Thus, the most distant feature we could possible see is, right now, 40 billion light year away. It wasn't 40 billion light years away when the light was emitted. The space from us to it stretched in the time it took the photons to get to us, and it stretched both behind the photon and in front of the photon.
http://www.geoffreylandis.com
you're no better or more accurate than religious beliefs.
They definitely are.
They are better or more accurate than religious beliefs if, and only if, their work can make predictions about things that can be measured.
Conventional big-bang cosmology definitely did make testable predictions: the cosmic microwave background; the isotope ratio of elements formed by nucleosynthesis in the high density plasma of the early part of the big bang.
Whether inflationary cosmology--or the even more speculative landscape cosmologies-- will make similar predictions is still somewhat open. Right now inflationary cosmology does have one success; it predicts the isotropy of cosmic background radiation even from regions causally disconnected in the early universe. It's hard to find another hypothesis that also makes this prediction, so inflation is getting to be pretty well accepted as a baseline, at least until some better model comes along that also fits the data. But there are many people looking for that better model.
http://www.geoffreylandis.com
Size of humans is right in the middle of that range.
...the future crusty old bastards are already drinking the Kool-Aid.
I always thought inflation occurred after the Big Bang, not before it. Wonder where I got that idea...
...the future crusty old bastards are already drinking the Kool-Aid.
Very cool, but got me wondering... So how come the gravitational force didn't collapse it into a black hole?
Another very tricky question. The answer is not very satisfying: the Schwartzschild solution ("black hole") is a spherical gravitational field embedded in flat ("Minkowski") space, but the universe itself isn't embedded in flat space; it is space (and it's also not flat).
In simplified form, a black hole has to have an "outside" to be defined in relationship to. The black hole is defined by the event horizon, a surface beyond which light can't escape... but you can't have such a surface unless there exists a "beyond".
You can, if you like, say that the entire universe is a black hole, in that-- by definition-- light can't escape from it.
http://www.geoffreylandis.com
The second problem is the Big Bang Theory is not-even-Science -- there is no way to replicate or reproduce the experiment!
I completely agree with your assessment of the one you colourfully name "Starts-With-A-Shit" since he gets his particle physics wrong all the time too. However I have to disagree with your assessment of the Big Bang Theory.
For a start it has made several predictions which have turned out to be correct: the relative abundances of the elements in the Universe and the cosmic microwave background. Secondly it is partly reproducible in the Large Hadron Collider in that we can recreate the conditions of the early universe to figure out the physics and then make predictions on how the universe would look today if it had started in a Big Bang.
There are still some unknowns such as Dark Matter and how the matter/antimatter asymmetry came about but that is one way to test the model: if we find that the physics behind these is incompatible with the Big Bang then we will have falsified the model. Hence since it makes predictions, is falsifiable and is partly reproducible it is hard to argue that it is not science.
Can you name any other type of thing that happens ONCE and only ONCE?
Science is about things you can observe. Whether there is just one of them, or many of them, isn't really an issue. The issue is whether you can observe it.
You can observe the universe, so making observations about the universe is science, even though there is only one universe. (At least, only one we can observe).
I think it would be outside science, since results need to be repeatable!
You can repeat measurements of the universe.
Hence you have this oddity, "the big bang" creating this *one* universe and all of space time and it only happens once, for some magic reason....
Ah, the "magic" reason is the tricky word here. If we can come up with hypotheses to explain why that can be tested by observations we can make, it's not magic any more. Often the hypothesis come first, and the tests later. When atoms were first proposed, for example, it was pointed out that they could not possibly ever be observed; they were just hypothetical objects that allowed us to make models about what could be observed.. But we measure and observe them now.
defying everything else we know.
But the whole point is to come up with hypotheses that don't defy everything we now know. And that's harder and harder as we know more and more.
And likewise Inflation, one magic thing happens, then gone, never to appear again. Again a fixup singleton.
Does the hypothesis have consequences that can be observed and measured? If it does, it's not relevant whether it happened once, or many times, as long as we can make those measurements. Can we measure it with observational astronomy? Can we create inflationary conditions with particle accelerators recreating conditions similar to the big bang? Can the inflationary fields themselves be measured in some other way we haven't thought of? Until we measure something, it's a hypothesis.
http://www.geoffreylandis.com
I am more concerned about the universe being 46 billion light years in all directions....More likely we can only see 46 billion light years.
Actually we can only see 13.8 billion light years in each direction because that is the age of the universe and so the furtherest possible distance that light can travel in that time. You should indeed be very skeptical about the 46 billion light year number because that is an extrapolation as to where the objects we can see now are but, without actual knowledge of the rate of expansion, there is no way to know whether that number is right. It's also rather strange to take a photo of something and then state the distance where the object is now rather than the distance shown in the photo.
However you should not be skeptical about the distance being uniform. If we lived in a 2D universe then you could imagine it as being on the surface of an expanding sphere. If you looked in all directions around you then the universe would appear the same but this would also be true for anyone else in the universe since you would all be sitting on the surface of a sphere. This is the same thing for our 3D universe but it is far harder to imagine!
Fuck Forbes. Fuck them to all fucking hell Don't EVER link to those motherfuckers again!
Now consider the probability that human beings made a fatal error in constructing the big bang theory. This number may be extremely small, but it is a gazillion times bigger than the former number!
The more likely possibility is that human beings made an error. Thus it is more rational to believe in the possibility with the greater probability, namely that human beings made a fatal error in constructing the big bang theory.
Welcome to David Hume's argument against miracles! It is valid.
1. You are ignoring causality.
2. You are ignoring the speed of gravity (which is very likely c).
3. You are ignoring the fact that nerve induction doesn't work all that quickly.
Don't just stand there, get that other dog!
Add UserCSS, e.g. with Stylish:
1) The whole requiring infinite energy to even get up to c part makes it a little tricky to go faster.
2) Your link is BS. It seems to be talking about some theoretical results from general relativity but completely misinterprets them and also presents them as experimentally verified. Actual experiments have measured the speed of gravity to within 1% of the speed of light: https://en.wikipedia.org/wiki/...
3) ???
...it was big enough to fill the entire universe. Even if it was the "size" of a mere soccer ball, there was no time or space beyond.
Yeah, the size of the universe is interesting from a purely academic standpoint but isn't it meaningless? I mean it's still the whole universe, right? Although toward the end of the article we have the implication that it WASN'T the entire universe - just what we can observe. So there may have been volume beyond the soccer ball. And if there was, does it matter? Does it affect our universe initial conditions?. And what's up with the superluminal expansion? And not just a little superluminal - it makes the USS Enterprise look like a slacker. At what point did the speed of light limit kick in and why? What changed? Something just doesn't make much sense. Can universal laws just change? Obviously they did - superluminal expansion wasn't just a feature, it was a necessity since density at that point had to make your run of the mill black hole look like a dense fog. So escape velocity was way over light speed. This implies things were weird as hell.
Okay. If the universe is 13.8 billion years old and the fastest stuff travels at the speed of light and the initial size of the universe is something "macro" in scale (between a soccer ball and a city block), then why isn't the universe 13.8 billion light years in diameter? Where does the 46.1 billion LY come from? Thanks!
FTL travel is time travel, assuming Special Relativity is correct (and we're going to have to revise a lot of things if it isn't).
Imagine two spaceships. each with an instantaneous communicator (an ansible). They are approaching at a speed so that the time dilation factor is 0.5. As they pass, they exchange ansible frequencies.
The guy on one spaceship spills his coffee into his lap an hour after the meeting. He fires up the ansible and sends the other guy a message about it, and asks for the other guy to send it back. Given the time dilation factor, it arrives after the other guy has traveled half an hour. The other guy repeats the message back. He's traveled half an hour, so the ship with the spilled coffee has gone fifteen minutes after the meeting, forty-five minutes before the spilled coffee, plenty of time to decide on a safer place to put the cup.
The only way to have FTL and not time travel is to have an absolute reference frame, which causes problems on its own.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
No matter where you are in a homogenous explosion. It always looks like you're in the middle. Or more actually everything is moving away from you isotropically and there is no information on your exact position relative to some "center of the universe".
If information wants to be free, why does my internet connection cost so much?
Surely this goes against everything we know about the expansion of space time? When the universe expands, it not like an explosion where matter expands into space or void. The actual space itself stretches and thus the ruler with it. Not to mention there's nothing to expand into as the universe is the entirety of everything. This is true even if you take into account the size of the universe being bigger than what we see in the observable universe due to the event horizon. So a universe pre-inflation of 1 ruler unit in radius will still be 1 ruler in radius unit today? What am I missing?
The speed limit is for things travelling through space, not space itself. It's the fabric of spacetime that's expanding and there is no speed limit for that.
Think of yourself walking across a room from one wall to the opposite wall. Let's say you have a speed limit of 1 metre per second. After 5 seconds you can't be more than 5 metres from the wall behind you. Now imagine that the entire room is expanding in all directions. You're still walking at 1m/s but the wall behind is now receding at a higher rate than your speed limit.