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Universe 250+ Times Bigger Than What Is Observable 506

Posted by CmdrTaco
from the size-of-a-good-reuben dept.
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."
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Universe 250+ Times Bigger Than What Is Observable

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  • by catbutt (469582) on Tuesday February 01, 2011 @04:28PM (#35072016)
    I mean, what's at the outer edge? A wall?
    • by MightyMartian (840721) on Tuesday February 01, 2011 @04:31PM (#35072066) Journal

      Can you show me the point where a circle ends?

    • by Ambitwistor (1041236) on Tuesday February 01, 2011 @04:34PM (#35072114)

      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.

      • by MBGMorden (803437) on Tuesday February 01, 2011 @05:06PM (#35072604)

        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".

        • I think the 'double back' mechanic works when you bring additional dimensions into the mix and assume that space has a positive curvature. Then, when you take off in a 'straight' line, you actually wind up going in a great big circle and a long, long time from now wind up right back where you started.

          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
      • 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.

    • by Cinder6 (894572) on Tuesday February 01, 2011 @04:34PM (#35072116)

      There's a wall and a telescope, where you can see into the alternate universe where everyone wears cowboy hats.

    • 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

      • 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

    • The Chinese are working on that.
    • by tverbeek (457094)
      It's all patently ridiculous. Why would God bother creating stuff that's too far away for Humans to observe it?
  • by BitterOak (537666) on Tuesday February 01, 2011 @04:28PM (#35072028)
    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?
    • Re:I'm confused. (Score:5, Informative)

      by mcmonkey (96054) on Tuesday February 01, 2011 @04:31PM (#35072068) Homepage

      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.

      • Re: (Score:3, Insightful)

        by Anonymous Coward

        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.

      • 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

      • by tmosley (996283)
        Hey, that gives me an idea for a new warp drive. 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.
        • 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 :)

    • 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.

      • That doesn't make any sense either. c is defined as the speed of light in space. So if space expands relative to some imaginary non-expanding absolute reference frame, then c would have been traveling _slower_ relative to the non-expanding reference frame before the expansion -- so you could still only see the same distance before the expansion.

        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
        • That doesn't make any sense either.

          Exactly. If space is expanding, what is it expanding into?

          • 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)

      by taylor (11728) on Tuesday February 01, 2011 @04:35PM (#35072140) Journal

      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.

      • by sznupi (719324)
        ...fortunately, we can still fear false vacuum decay hitting us at any moment ;)
      • by kalirion (728907)

        Basically this means an acceptable method of FTL without involving worholes is to create a local space expansion wave to surf on :)

    • You'll never observe light that is traveling away from you.

    • by ad454 (325846)
      General Relativity does not have a speed of light constraint on the expansion of space itself. It is thought that during the inflationary period after the big bang that the universe went though a rapidly expansion phase where space expanded much faster than the speed of light.

      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
    • 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

    • 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.

      • An alternative theory is that the speed of light used to be much higher in the early universe (like 60x higher). This is known as the variable speed of light (VSL) concept [wikipedia.org]. There is a documentary from 2000 called "Einstein's Biggest Blunder", that gives a good overview of how it was developed.
  • First, How can you use a bayesian model to average results into a precise number?
    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?
    • by jfengel (409917)

      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

    • 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)

    by solarlux (610904) <noplasma.yahoo@com> on Tuesday February 01, 2011 @04:32PM (#35072092)
    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).

    But crazy conjecture aside, does this talk of the 'full size' of the universe mean that the article even had its starting premise wrong?
    • 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.
      • 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.

    • 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.

    • by microTodd (240390)

      I've heard that theory as well, but check out my sig.

    • by mcmonkey (96054)

      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.

  • The bigger the fool the more confidence they have.
    • by Chapter80 (926879)

      The bigger the fool the more confidence they have.

      Hmm, you say that with a lot of authority.

  • by MrLogic17 (233498) on Tuesday February 01, 2011 @04:36PM (#35072152) Journal

    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"?

    • by SpacePunk (17960)

      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.

    • 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

      • by artor3 (1344997)

        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?

    • by sznupi (719324)
      Do you ever want to, while standing on the surface of a large sphere (Earth being a good approximation), to travel so far that the "edge" will come into view of your horizon?
    • by dkleinsc (563838)

      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.

    • The assumptions in the article (and much of Big Bang theory) are wrong -- the only reason we can't see past 14 light years away from us is that the galaxies themselves are moving away from us at close to the speed of light at that distance -- the redshift tends to 1.0 at a distance of slightly less than 14 light years. We can't see past that point because the light will never reach us.
  • 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?

    • by sconeu (64226) on Tuesday February 01, 2011 @04:59PM (#35072506) Homepage Journal

      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".

  • 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.

  • 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.

    • 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

  • by tekrat (242117) on Tuesday February 01, 2011 @05:01PM (#35072540) Homepage Journal

    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.

    • By far, that is my top favorite ST:TNG episode. Not sure why. (maybe it's my thing for redheads...)

    • 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.

    • 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.

  • In 50yrs we'll find the universe is 500+ times larger. Heisenberg is rolling in his grave.
  • by MHolmesIV (253236) on Tuesday February 01, 2011 @05:11PM (#35072666)

    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]

  • by WilliamTheBat (1762376) on Tuesday February 01, 2011 @06:03PM (#35073344) Homepage
    For those of you who did not bother to read the whole article, there's a really important nugget that's lost in the 250+ times headline. The results show that the most likely curvature of the universe = 0. This means the universe, as near as our best minds can tell, is infinite. All the same dusting of galaxies in every direction, infinitely. Infinity is not a concept most people grasp easily. People ask things like "what's outside the universe?" but there is no outside, as "directionality" or "position" have no meaning outside the context of the universe. Likewise, there's no "before" the universe, as time has no meaning outside the context of the universe. My instinct says that we'll eventually come up with a nifty model of reality that includes a non-intuitive description of "position" that causes everything to make mathematical sense and has both quantum physics and relativity as predictable consequences.. but that is pure speculation. And it's a sure bet it'll be even harder to wrap our heads around than what we have now.
  • by DanielRavenNest (107550) on Tuesday February 01, 2011 @10:02PM (#35075554)

    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.

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