Universe 250+ Times Bigger Than What Is Observable 506
eldavojohn writes "The universe is only fourteen billion years old so we are unable to observe anything more than fourteen billion light years away. This makes it a bit difficult for us to measure how large the universe actually is. A number of methodologies have been devised to estimate the size of the universe including the universe's curvature, baryonic acoustic oscillations and the luminosity of distant type 1A supernovas. Now a team has combined all known methods into Bayesian model averaging to constrain the universe's size and their research is saying with confidence that the universe is at least 250 times larger than the observable universe."
What does that even mean? (Score:3)
Re:What does that even mean? (Score:5, Insightful)
Can you show me the point where a circle ends?
Re:What does that even mean? (Score:4, Informative)
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Or what lies to the north of North Pole.
Newcastle upon Tyne [google.co.uk].
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To quote Arkady Darrel: "A circle has no end".
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So at the end of the Universe lies Trantor?
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No, but I sure can show you an infinite number of points that lie outside the circle.
Re:What does that even mean? (Score:5, Interesting)
Not if you live in the one dimensional space curved in a 2nd dimension defined by the circle you can't.
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Inside the circle, then!
Re:What does that even mean? (Score:4, Informative)
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Simple. It ends right before where you started off.
Re:What does that even mean? (Score:5, Insightful)
There's nothing "physical" about the edge of the observable universe. It's just the boundary between galaxies whose light has had time to reach us, and galaxies whose light is still on its way.
Re:What does that even mean? (Score:5, Interesting)
I don't think he's referring to the edge of the "observable universe". The article states that the universe is 250x the size of the obserable universe. Hence, the universe itself, outside of being observable, has a limited size. That naturally leads to a question of "what happens a the end".
Numerous analogies have always been used to describe this. Most have already been brought up in this thread (circles, etc). The most famous is that of a balloon. To a 3d observer, a balloon's surface is of limited space. To the ant though, the surface of balloon is endless.
That observation never quite sat with me though. It works for an ant - incapable of reason, but swap out the situation for a PERSON sitting on another circular surface (like, say, a planet), and we have figured out quite readily that our surface is unending but finite - it's obvious - go in another direction and you end up circling back.
By the same token, you can't just easily dismiss a perceived infinity of the universe via analogy as a meaningless question. There must be a logical mechanic behind it. Either the universe literally ends with a wall (highly unlikely), it truly is infinite, or, there is some mechanism by which you "double back" and circle back to your previous position. Just personally, I've never seen a truly convincing mechanic for explaining just how the last one would work. The infinity mechanic makes more sense. Not that I'm saying that the universe is definitely infinite. I'm just saying that before I truly embrace that ideas I need a working model of how it would work as perceived infinity, outside of an analogy or "it just works that way".
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That leads to a lot of other questions, though. Like, if you could see far enough, does that mean you could look left, spot a distant galaxy, and look right and see the same galaxy from the other side?
A
I/We/Gaia (Score:2)
take offense to this comment. I/We/Gaia have beautifully curved boundaries that I/We/Gaia are proud of. In our assimilation of the galaxy, we will make sure to prioritize your solar system and eradicate this stupidity.
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No, he was right, or at least closer. It's actually about 90 billion light years across (in diameter), 45 billion light years in radius, at least, measured in terms of comoving or proper distance (what you would think of as roughly the "actual" distance today).
14 billion is roughly the age of the universe, so obviously the light at the boundaries of the observable universe had to be emitted about 14 billion years ago. However, the universe was much smaller back then and has expanded a lot since. So the s
Re:What does that even mean? (Score:5, Funny)
There's a wall and a telescope, where you can see into the alternate universe where everyone wears cowboy hats.
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I salute you, fellow futurama buff!!!
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http://www.futurama-madhouse.net/fashion/315cowboy.jpg [futurama-madhouse.net]
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I think I misunderstood your question in my previous response. By "outer edge", do you mean "edge of the universe outside the observable universe"? If so, there is no edge to the universe. However, you can still talk about the universe's size.
Imagine the universe to be like the surface of a sphere. To a "flatlander" living in the surface, there is no edge. They can go round and round as much as they want. The "observable universe" would be some part of this surface, a circular "cap" centered on some p
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While your comments are appreciated, I've always considered such an explanation as crap. If the matter within the universe is expanding, it has to be expanding into something. What is that something?
Saying it's like a balloon proves the point. The balloon may be expanding, but it is expanding into the box/room/whatever. Your explanation simply says the balloon is expanding into itself.
The same goes for the origination of the Big Bang (or Expansion). You can't say the matter in the universe was in a ball
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I'm confused. (Score:3)
Re:I'm confused. (Score:5, Informative)
Supposedly matter cannot move faster than light. But the expansion of the universe following the Big Bang involves the dimensions of space-time. It's not the movement of matter, but the movement of existence itself in which that matter exists which can produce FTL expansion.
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Which means that galaxies which are observable right now, will eventually blink out of (visible) existence due to the speed with which they are departing away from us.
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Time and space warp around a black hole. If we assume that the black hole really does affect the curvature of time, then when we collapse all matter into a singularity we get a super massive black hole that not only warps space into a sphere (like a regular black hole-- there is no physical path out), but also warps time into a sphere.
Thus if the universe is cyclically expanding, slowing, contracting, then repeating a big bang event, what we have is a closed loop time system: All of history will repeat i
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Just zap a region of space with an aging gun, which causes that region of space to expand faster than the speed of light, and ride the bubble wherever you want to go.
Actually, a negative energy gun would do nicely [wikipedia.org]. Oh, and you'd probably need some tachyons :)
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You have this wrong. First of all, there was no matter at the Big Bang. Second of all there's nothing in physics that says space itself is bound by the speed of light. That is a limit to matter, and probably to all force propagation as well, but space isn't matter or energy, it isn't a force, and thus it is not bound by those particular rules. Thus inflationary theories do have space expanding at a much faster rate than c.
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The second problem is the concept of a non-expanding absolute reference frame. There should be no such thing under the Big Bang model -- space didn't exist before
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That doesn't make any sense either.
Exactly. If space is expanding, what is it expanding into?
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It's not expanding into anything, at least by standard physics (superstring derivatives alter that).
The best analogy I've ever heard is to think of the surface of a balloon, except in two spacial dimensions as opposed to three. As you inflate the balloon, points on the balloon grow farther apart, but the surface isn't growing into another medium.
I believe the technical term is a "compact manifold". A circle, for instance, is a compact manifold, in that there is no actual end point, and yet the circle is o
Re:I'm confused. (Score:5, Interesting)
The key idea is that of inflation: general relativity allows for the distance between points to increase faster than the speed of light. Alan Guth's theory for inflation proposes that this in fact occured in the early universe, and the theory is now backed up by observations of fluctuations in the microwave background radiation (among others), where microscopic fluctuations were "frozen in" due to the rapid expansion. The consequence of this inflation is that much of the current universe is not within our 14 Gyr lightcone.
As a side note, the big hub-bub about dark energy is that it appears (based on current observations) that our universe may be entering a second inflationary period. Fortunately, the timescale for this is on the order 100 Gyr, so it will be unlikely to effect our lives directly.
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Basically this means an acceptable method of FTL without involving worholes is to create a local space expansion wave to surf on :)
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You'll never observe light that is traveling away from you.
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http://en.wikipedia.org/wiki/Inflation_(cosmology) [wikipedia.org]
Think of ants crawling at a fix speed, called "C" on the surface of a balloon, while someone is blowing up (inflating) that balloon so that the rate of increase in the circumferenc
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You can't see everything past the midpoint, or the center of origin. It's the classical two trains leave the station at Noon, both heading in different direactions at the speed of light, you'll never be able to see further back (or farther away) than the station.
However what they are saying additionally is that there were 250 trains leaving the station, all in different directions at the speed of light, and we'll never be able to see anything but our own train, and the path it took, scenery it passed by.
How
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If the universe started with a big bang, with all matter originated in an extremely compact volume, and if it's radius can't expand faster than light, then there should be no points in the universe beyond what we can see (as limited by light speed.) What am I missing?
What you describe is known as the Horizon Problem [wikipedia.org]
The current theory that tries to explain this is called Inflation [wikipedia.org]. Basically, it assumes that after the Big Bang there was a period of Inflation where space time itself expanded faster than the speed of light.
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implying...? (Score:2)
Second, Why are you bothering to do this from theories on top of inelegant theories?
Third, if the universe actually is that size What does that mean for the heat death of the universe?
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How can you use a bayesian model to average results into a precise number?
"At least 250" is not a precise number.
Why are you bothering to do this from theories on top of inelegant theories?
Good question. Practically, nothing. It's one of those "maybe we'll figure out something important, like velcro or tang or space pens in the process" things. Plus, people really like to think about the origins and destination of the universe, even though the time scale (10^10 years) is far bigger than the scale of human life (10^2).
if the universe actually is that size What does that mean for the heat death of the universe?
Nothing, directly. The assumptions that went into the model call for a universe that undergoes heat death (justified by observation), a
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1. You assign probabilities to the various hypotheses according to how well they agree with observed data, and form a weighted average.
2. The theories aren't inelegant. They agree quite well with observed data, down to the detailed angular power spectrum of the cosmic background radiation. There are just a few uncertain parameters that need to be nailed down.
3. The universe will probably expand forever and suffer a "heat death". Or, if not forever, it will expand for a very long time and effectively suff
how big? (Score:3, Interesting)
But crazy conjecture aside, does this talk of the 'full size' of the universe mean that the article even had its starting premise wrong?
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The "Universe" is understood to be spatially bound (though growing since the Big Bang). The Multiverse involves infinite parallel universes existing on different membranes of higher dimensions.
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I think you might be confusing the Universe and the Multiverse. What you are describing sounds similar to M theory, but you said "Universe", which doesn't make sense. The "Universe" is understood to be spatially bound (though growing since the Big Bang). The Multiverse involves infinite parallel universes existing on different membranes of higher dimensions.
Yes, because that makes so much more sense.
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Yes, many cosmologists think the universe may be infinite. The size estimate is a lower bound. The universe is at least 250 times bigger than the observable universe. It could actually be infinitely bigger. We can't prove that. We can just put a lower bound on its size.
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I've heard that theory as well, but check out my sig.
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I recall reading a Scientific American article that indicated that the Universe had infinite size and mass, meaning that probabilistically, the exact construction and configuration of our observable universe would repeat itself (infinity tends to have nasty implications like that). Or to put it another way, another you is reading this somewhere (actually, an infinite number of you's, to be precise).
What are the chances another me somewhere is working instead of killing time on /.?
I should probably thank that me for covering for the rest of us.
My finding (Score:2)
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The bigger the fool the more confidence they have.
Hmm, you say that with a lot of authority.
What if were were near the "edge"? (Score:3)
From what I gather, we're stuck somewhere in the middle-ish of the universe. What if were were located near the "edge" of the expanding universe, and the "edge" was within our observable light cone. What would we see? Nothing? or is the "edge" of the universe expanding faster than the speed of light, therefore one could never see the "edge"?
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The hell of it is that not only are we in the middle of the universe, we are also at the edge of the universe.
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Think of the universe as a balloon. (A REALLY big balloon.) We're 2-dimensional creatures (say, squares... maybe a trapezoid) living on the inside surface of it. We can look left, right, forward and backwards, but can't look up or down. You could travel all over the balloon-universe and never find an edge. Yet, the balloon-universe has a definite size. It isn't infinite. The same is true for our Universe. If you could traverse the entire Universe (ignoring the expansion of the Universe and the huge
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Doesn't that suggest that when (if?) the universe stops expanding, it would be possible to look through a theoretical super-telescope and see your own galaxy as it existed a zillion years ago?
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From what I gather, we're stuck somewhere in the middle-ish of the universe.
Also, Earth was the middle of the Solar System. And the Solar System was in the middle-ish of the Milky Way. In other words, we've been spectacularly wrong about that sort of thing several times already, and it's safe to say we're probably not middle-ish of anything.
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Not a physicist, but wish I were (Score:2)
Correct me if I'm wrong, but wouldn't our observable constrain be 14 billion light years IF we were at the epicenter of the big bang?
Instead, shouldn't there be some area of the sky that we can only find much younger stars, and others that appear further away?
Re:Not a physicist, but wish I were (Score:4, Insightful)
We *ARE* at the "epicenter".
Consider a balloon with polka dots on it. When it inflates, each dot expands away from the others. We are a polkadot on the three-dimensional surface of space-time, and every point in the universe is expanding away from us as space-time expands. If we were in M31, we would still see ourselves at the "center" of the expansion. If we were in that galaxy 14 Billion light years away, we'd still see ourselves at the "center".
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Which city is closest to the center of the Earth?
Since Earth is an oblate spheroid, it would probably be the most northern or southern coastal city on Earth.
This is probably it (city > 1000 people): http://en.wikipedia.org/wiki/Longyearbyen [wikipedia.org]
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Which city is closest to the center of the Earth?
I'm not sure, but there are several settlements on the Dead Sea, and the answer is likely to be one of them (assuming the name "city" can accurately be applied to any of them. :)
(Yes, I understand the point you were trying to make, but this is slashdot, so I'd be falling down on the job if I didn't pick nits with your argument.)
That is some interesting numbers (Score:2)
That is some interesting numbers but that almost indicates that the radius would be more than ~6 times thus the universe is actually ~88 billion years old... yeah crude math aside... still way more than before.
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nm... I should start to RTFM.
Curvature prior (Score:2)
Why such a strange prior? I understand that they believe that the curvature is 0, but how do they know they should drop it down so quickly? What about the rest of the prior, why does it look so strange? What would happen if they changed the prior. I'm guessing that tweaking the prior would yield greatly different universe sizes.
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The figure doesn't acutally show the priors (despite the labels). It shows the posteriors (inferred using the labeled priors). For example, the "Astronomer's Prior" gives uniform probability between -1 and 1. But the posterior implied by that prior, and the observed data, is highly peaked near zero, indicating that the data favor a flat universe.
The odd peak occurs because there are really separate models being considered. Some of them are flat-universe (zero Omega) models, and some aren't. If you give
The nature of the universe, answered years ago... (Score:5, Funny)
Beverly:
If there's nothing wrong with me...maybe there's something wrong with the universe!
Here's one you shouldn't be able to answer...
Computer, what is the nature of the universe?
Computer:
The universe is a spheroid region, 705 meters in diameter.
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By far, that is my top favorite ST:TNG episode. Not sure why. (maybe it's my thing for redheads...)
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Beverly:
If there's nothing wrong with me...maybe there's something wrong with the universe!
Computer:
The universe is a spheroid region, 705 meters in diameter.
On no! I hope it doesn't crush 'er.
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Also from TNG, Episode 4x05 "Remember Me":
Beverly: What is the primary mission of the Starship Enterprise?
Computer: To explore the galaxy.
Beverly: Do I have the necessary skills to complete that mission alone?
Computer: Negative.
Beverly: Then why am I the only crew-member? (the computer takes a moment to process and makes a strange noise) Aha, got you there.
Computer: That information is not available.
Math is math. (Score:2)
Original summary is entirely wrong. (Score:4, Interesting)
The submitter obviously did not read his own links. While the universe is only 14 billion years old, the _observable_ universe is > 90 billion light years across.
This is due to expansion, which stretched the wavelength of the light coming towards us, so redshifting those galaxies. It also makes those galaxies appear to be moving away from us at many multiples the speed of light, although they're not really moving at all, space is expanding.
An explanation [scienceblogs.com]
Shape of the universe in a nutshell - Infinite (Score:5, Informative)
For those who are confused... (Score:3)
The cosmic background radiation we observe today has taken 13 Gigayears to get here. In all that time, the gas which emitted that radiation has not been running away from us at near lightspeed. Rather it has had random motion relative to it's neighborhood of around 0.001c., and the geometry of space has been expanding about 1000-fold since that time. That expansion of the geometry both stretches the wavelength of light from visible at 3000 Kelvin down to microwave at 3 Kelvin, and also adds to the volume of space both behind and ahead of a traveling photon. No part of space is stretching locally very fast, but the total stretching of space across the universe can exceed apparent lightspeed without violating relativity, because relativity operates locally, not globally across the universe.
Similarly, conservation of energy applies locally, but not to the universe as a whole. If dark energy is constant per volume of space (the theory of how it works), then the total energy of the universe increases as it grows. If that sounds weird, it is. Modern physics is just not intuitive to us humans that mostly deal with non-quantum, non-relativistic stuff on a daily basis.
Re:Speed of Light? (Score:5, Interesting)
It is, but oddly enough that does not bind the expansion. Space can be expanding faster than c and I believe the inflationary theory says just that.
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Space can be expanding faster than c and I believe the inflationary theory says just that.
Damn fed printing money, now see what they've done.
Re:Speed of Light? (Score:5, Informative)
Some physicist is very welcome to fill in here, but I'm not sure it's correct to say that the universe "expands faster" than the speed of light. Locally, the expansion is slow, and objects aren't really "moving away" from each other -- rather more space is added in between them.
Think of it like blowing up a balloon with ants walking around on the surface. The distance between ants could increase faster than they can move, but none of the ants are moving relative to the space they occupy.
As a side note: One theory of the ultimate fate of the universe is that the expansion rate will increase past the point where the observable universe becomes smaller than atoms and other particles (a higher expansion rate means objects must be closer to each other for light travelling between them to overcome the expansion of the distance between them), essentially ripping all matter apart.
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Some physicist is very welcome to fill in here
Really?
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FTL Expansion == Inflationary Epoch (Score:4, Informative)
It is, but oddly enough that does not bind the expansion. Space can be expanding faster than c and I believe the inflationary theory says just that.
It did so for a VERY short while following the big bang: a period of superluminal expansion known as the Inflationary Epoch. [wikipedia.org]
Physicists like to separate notable periods in time on a logarithmic scale, referring to each as the "Whatever" Epoch. As novel as the system itself is, what's most novel is how tiny of a portion of it our planet will be around for.
Recommended reading for the curious. [amazon.com]
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250 * (14.5 billion)*4/3*pi lightyears is as good as infinite as far as I'm concerned. hell, even (1Million)*4/3*pi Ly is big enough for me.
Re:Hence infinite? (Score:5, Funny)
(640k)*4/3*pi ought to be big enough for anyone.
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But then 250 * (14.5 billion)*4/3*pi light years is also as far from infinite as zero is.
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Didn't bill gates say 640K * (14.5 billions) * 4/3 * pi should be enough space for everybody, no matter what the activity, how much civilization expands ;)
or something like that :)
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Of course still such estimates should help with cosmological models, science in general, or understanding our negligibly minuscule (heck, not even a speck of random noise...) place in the Universe (yeah, like that will happen soon...)
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But what I really want to know is...
How do fucking magnets work?
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The black matter universe is bigger than ours :-(
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Man was created in God's image, so if they can't comprehend something obviously God can't do it.
Expanding universe beyond comprehension in size, stars and planets too numerous to count, nah, since those concepts make our heads hurt and make us feel insignificant he's only interested in our planet and everything else is just props for the stage.
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> You can't call a line infinite if you've found one end of it.
Of course you can. Consider a list of the natural numbers, for example.