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An Older, Larger Universe 479

Josh Fink writes "Space.com has a very interesting article as part their weekly mystery Monday series about a new calculation that shows that the Universe is actually much older than than the 14.3 billion years old that was established in 2003. From the article, "...the universe is instead about 15.8 billion years old and about 180 billion light-years wide." The calculations were based off of a recalculation of the Hubble Constant which dictates how fast the universe is expanding, and they found it is actually 15% slower than previously thought. The findings will be printed in an upcoming edition of Astrophysical Journal."
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An Older, Larger Universe

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  • What is... (Score:5, Funny)

    by Anonymous Coward on Monday August 07, 2006 @09:43AM (#15858514)
    1.5 billion year between friends? She's still under 18.0 billion, so be careful! :/
  • by bblazer ( 757395 ) * on Monday August 07, 2006 @09:43AM (#15858517) Homepage Journal
    Those are some huge numbers. What gets me going though is what is outside of those 180 billion light years of width? What happens when you hit the border? Is there a passport checkpoint?
    • by Skynet ( 37427 ) on Monday August 07, 2006 @09:46AM (#15858539) Homepage
      Aliens playing marbles with other universes.
    • by Rude Turnip ( 49495 ) <valuation@gmail.WELTYcom minus author> on Monday August 07, 2006 @09:48AM (#15858549)
      Correct me if I'm wrong, but I think at the end of 180 billion light years you've just wrapped around to the other side, in a similar manner to travelling around the world. If there was a "border," whatever is outside that border is also part of the known universe.
      • by Promodeus ( 993697 ) on Monday August 07, 2006 @10:25AM (#15858781)
        It depends on the shape of the universe... If you think of an Omega constant less or equal than 1, it's either flat or convex, in wich case the frontier diverges... if, on the other hand, it's more than one, you could have your spheric universe. Another missconception, AFAIK, is withe the "outside of it". The universe, by definition, is existence itself, in the form of time-space. There can't be an outside because there is no existence there, not even the absence of matter... Yeap, this is the place when phisics turn philosophers...
    • Don't you watch futurama? Once you get to the edge of the universe there's a lookout point where you can look at the other universe.. (yes, there's only 2 universes)
    • by tsa ( 15680 ) on Monday August 07, 2006 @09:54AM (#15858592) Homepage
      How can it be 180 billion light years wide and just 15.8 billion years old? If the Big Bang theory AND Einsteins theory that nothing can go faster than light are both correct, the universe can only be 15.8 * 2 = 31.6 billion light years wide. I am a lowly nanotechnologist, and for them everything bigger than a mm is HUGE, so the size of the universe is incomprehensible beyond imagination to me. Can anyone with more knowledge about the universe elaborate on this?
      • by Skynet ( 37427 ) on Monday August 07, 2006 @09:56AM (#15858604) Homepage
        The expansion of space isn't governed by the speed of light.
      • by CosmeticLobotamy ( 155360 ) on Monday August 07, 2006 @09:57AM (#15858613)
        From the link in the article:
        Need a visual? Imagine the universe just a million years after it was born, Cornish suggests. A batch of light travels for a year, covering one light-year. "At that time, the universe was about 1,000 times smaller than it is today," he said. "Thus, that one light-year has now stretched to become 1,000 light-years."

        Which is one of the many reasons I consider any science that hasn't gone into producing a working television at least 95% bullshit.
        • Well, that's exaggeration, but whenever I hear "the universe is expanding, like we thought 2 and 4 times ago, not contracting, like we thought last time and 3 times ago" or "well, the universe is 10 billion, not 8 billion light years wide", that to me comes across as a sort of modern version of "1000, not merely 800 angels can dance on the head of a pin".

          If the data are that ambiguous, why talk to mass media?
      • Space can expand "faster" than the speed of light. besides, relitivity says that nothing with mass can move at the speed of light, nothing about faster or slower. Imagine a moving sidewalk, the speedlimit only applies to your speed with respect to the sidewalk, not the side walk itself.
      • This Wikipedia (untrustworthy, waah waah ;-)) article covers both yours "greater than speed of light" and the up-modded grandparent's "universe border" question: Metric expansion of space [wikipedia.org]. If you really dislike Wikipedia, I guess there are something similar elsewhere, probably even better too. :-)
      • The observable universe is as old as you can observe - currently around 14 billion years ,give or take a billion. The size of the universe is independent of the size of the observable universe but is a function of the curvature [wikipedia.org] of the universe - the big bang did not originate at where the sun or our galaxy is and evenly expanded.

        The most simplest explanation is: Before the big bang, there was no space-time. The universe expanded into space-time and the space-time is expanding since then. Also just after th

    • by BlackCobra43 ( 596714 ) on Monday August 07, 2006 @09:58AM (#15858620)
      Just like "What came before there was time". Without a frame of reference, words like "beyond" or "before" become meaningless. You might as well ask what lies "beyond" the point you see on a cartesian plane.
    • by D-Cypell ( 446534 ) on Monday August 07, 2006 @10:01AM (#15858634)
      What happens when you hit the border? Is there a passport checkpoint?

      It is probably biometrics now but who cares when there is so much to do in this universe. Infact, anyone who wants to leave this universe is clearly unpatriotic anyway.
    • Is there a passport checkpoint?

      No, but I hear there is a pretty decent restaurant at the end of the universe. Just make sure you tip the robot parking your car.

    • "What happens when you hit the border?"

      There is no border. That's like asking "What's north of the North Pole?" The question is nonsensical.

      Imagine the Universe as being the 1-dimensional surface of a ball. It makes no sense to talk about the "border" on the surface of a ball--there is no border. If you go in any direction on the surface, you'll never hit an edge; you'll just keep going around and around in circles.
    • I believe Stephen Hawking has answered this question by asking "What's north of the North Pole?" which helped a lot for my own understanding.
    • What gets me going though is what is outside of those 180 billion light years of width? What happens when you hit the border?

      How could you hit the border since you would need to go faster than light to hit it? (right?)

  • by Alicat1194 ( 970019 ) on Monday August 07, 2006 @09:43AM (#15858519)
    Man...that's dead in dog years!
  • by eldavojohn ( 898314 ) * <[moc.liamg] [ta] [nhojovadle]> on Monday August 07, 2006 @09:44AM (#15858520) Journal
    The Hubble Constant [wikipedia.org] is based on the idea that the redshift of spectrum of light reveals how quickly it is moving away from you. Similar to the Doppler effect with sound.

    I am not a physicist but I recall another article [slashdot.org] that speculated that light may not always have traveled at the same speed. If this is true and we are measuring light that is ~90 billion years old, doesn't this drastically effect the red light shift that is so dependent on the constant of the speed of light?

    They didn't go into detail in the article except that it is a new recalculation using a pair of stars instead of a single star. I do not believe this alleviates the problem of possible change in constants regarding light and its redshift, however.
    • You have to understand that in all scientific fields, especially one as new and quickly evolving as Cosmology, there are a LOT of theories. Just because one was picked up by the mainstream media, it doesn't mean it is a widely accepted theory. All that happened here, is they recalculated the Hubble Constant(something that happens fairly frequently) And the theorized age of the universe was changed as a result of that (the age of the universe is the inverse of the hubble constant) This doesn't adress the t
  • by Anonymous Coward
    so good for its age! Gotta hand it to the old Universe there - it kept itself up!

    Expanding, contracting, etc.. really kept it in shape! Helped it age gracefully! This is a lesson kids, eat well, exercise, drink moderately , and you too can look 14 Billion years old when you're 15.8!

  • Old (Score:5, Funny)

    by HugePedlar ( 900427 ) on Monday August 07, 2006 @09:45AM (#15858526) Homepage
    As long as it's still older than 6000 years I'm happy.
    • Re:Old (Score:3, Insightful)

      by Skynet ( 37427 )
      You wouldn't be happy to find out there really is a God? :)
      • No, looking at the world around me he is either a nowhere near almighty or he is not such a nice guy at all or just doesn't care. In any way its easier to just assume there is no god since there is about as much evidence for a god as there is for invisible pink elephants.
  • How did they figure that out and what's outside of that?
  • This is how we lose Mars landers, after all...
  • If the universe is 15.8 billion years old, then shouldn't the universe be 31.6 billion light years across? Has the speed of light changed at some point?
    • I took some cosmology in college but I don't remeber much and theories are very fluid and prone to change, but I seem to remeber learning somthing about acclerated expansion in time shortly after the big bang. I also remeber a professor making the distiction between an object not being able to travel fater than the speed of light but nothing prevents the space in between to objects can increase faster than the speed of light.

      IANAP, so take it with many grains of salt.
    • Has the speed of light changed at some point?

      Here's the memo [space.com] - summary: Yes. The speed of light in a vaccuum has changed as the universe grew up.

      If the universe is 15.8 billion years old, then shouldn't the universe be 31.6 billion light years across?

      As well as a constant C, you are also assuming that the universe grew evenly in every direction. I don't know whether that is true.
    • Nope. Compare with the old "dough" analogy, with the yeast causing expansion in every part of the dough at each point in time -- no specific signal is transferred to tell the universe to expand. It's an inherent property in spacetime. On the other hand gravity and the other fundamental forces are actively "transmitting" information, limited at the speed of light, to try to keep things together at an energy minimum. You're expanded by some atto-meter or whatever per second, but the electrostatic forces tie y
    • SPACE.com has an explanation for why those numbers aren't what one would think [space.com]:

      The universe is about 13.7 billion years old. Light reaching us from the earliest known galaxies has been travelling, therefore, for more than 13 billion years. So one might assume that the radius of the universe is 13.7 billion light-years and that the whole shebang is double that, or 27.4 billion light-years wide.

      But the universe has been expanding ever since the beginning of time, when theorists believe it all sprang fort

    • "If the universe is 15.8 billion years old, then shouldn't the universe be 31.6 billion light years across? Has the speed of light changed at some point?"

      Just because objects can't move away from eachother faster than the speed of light doesn't mean that the space between objects can expand faster than the speed of light. During the inflationary period, the Universe was expanding at an exponential rate. From Wikipedia:

      "Most scientists estimate the duration of the inflationary epoch as 10^-32 of a seco
      • In other words, rather than there being objects moving away from eachother faster than 3*10^8 meters per second, it was as if the definition of a "meter" was changing.
      • That should read: "Just because objects can't move away from eachother faster than the speed of light doesn't mean that the space between objects can't expand faster than the speed of light."
    • The initial expansion was MUCH faster than the speed of light. c is the limit that governs speed in a vacuum. But by definition the early (first 400,000 years) expansion (or inflation) of the universe was expanding into NOTHINGNESS, not vacuum. For a period of time the universe expanded at many times the speed of light.
  • Question (Score:2, Interesting)

    by Anonymous Coward
    If the universe is 15.8 billion years old and 180 billion light-years wide, wouldn't that mean that the outermost parts of the universe travel or have travelled around 5x faster than the speed of light?
  • So if it's 180B light-years wide, but 15B years old, does that mean that on average, if it started as a singularity, it has expanded at 10x the speed of light since the beginning of time?(tm) Do I get the Nobel prize in physics now?
    • So if it's 180B light-years wide, but 15B years old, does that mean that on average, if it started as a singularity, it has expanded at 10x the speed of light since the beginning of time?(tm) Do I get the Nobel prize in physics now?

      Speed of light is constant, but time itself is not. Time is relative to where you are in the universe and how fast you are traveling. As in the ratio to light years to actual years is kind of iffy depending on how far and how fast you travel.

      You know... Travel at the speed of lig
    • Read up on inflation theory [wikipedia.org], which says the universe did have a very sudden expansion (inflation) very early on.

      If the universe is 180 gigayears across, but 15 gy old, that just means that many parts of the universe cannot "see" each other.

  • by Opportunist ( 166417 ) on Monday August 07, 2006 @09:50AM (#15858566)
    ...so what changes with this revelation? Did this change anything? Give us new insight? Did it support or crush any theories?

    I mean, it's nice by itself and all, but I'd be highly interested whether that has any implications other than changing the universe from being old to being older than we thought.
    • The early history of the universe is complicated. It had an early "inflationary period" in which things moved a lot faster than light. (That's why it's more than 30 billion light years across, to answer the question a lot of people have asked in this thread already.)

      Understanding the way the rules of the universe have changed over time is crucial to understanding what happened at the big bang. And, perhaps more importantly, what happened to make the early universe "clumpy", rather than smooth, which is wha
    • What is potentially troubling with this, and why I am skeptical of the implications for the Hubble constant, is that the age of the Universe had been narrowed down with a decimal point to 13.7 billion years, which means that the uncertainty in that number is +-100 million years or so. This is completely outside of the error bars. And the previous number had been honed in upon by not just the WMAP microwave background probe, but by many independent observations of Type Ia supernovae. It seems more likely
  • How can it be 180 billion light years wide and be 14.3 billion years old?

    If it expands at the speed of light shouldn't it be 14.3 billion light years wide? Or 24.6 if they're not measuring from the point at which the big bang occured?

    Or is it measuring the (estimated) circumference of the universe?
  • by Crashmarik ( 635988 ) on Monday August 07, 2006 @09:51AM (#15858570)
    Cosmologists have to be the weathermen of astronomy. Every five to ten years they come up with their definitive measurements of the (age,shape,nature, ending,begining pick one or more) universe. Once they have settled into an attractive basin they defend the viewpoint religously and then in five to ten years it happens all over again. If you catch a cosmologist between shifts they act as if the current viewpoint is the be all and end all.
  • Poor Douglas (Score:3, Interesting)

    by TheRaven64 ( 641858 ) on Monday August 07, 2006 @09:52AM (#15858580) Journal
    In 1996, the Hubble Constant was estimated as being 42. At the time, Douglas Adams was quoted as saying that it does crop up surprisingly often.

    Sadly, according to TFA and Wikipedia, it is now believed to be about 71. These seem so far apart that I wonder if the same units were used for both estimates.

  • the universe is instead about 15.8 billion years old and about 180 billion light-years wide
    Wouldn't that mean that the universe has been expanding at several times c since the big bang? How does the universe come to be 180 billion light-years across in only 15.8 billion years, if nothing travels faster than light?

    • if nothing travels faster than light?
      You answered your own question. Nothing can expand faster than the speed of light. In particular, the space between galaxies can expand faster than the speed of light. The expansion of the universe isn't about a bunch of galaxies flying apart from each other from an initial explosion like shrapnel from a bomb. It's a about the expansion of space itself, and that is something entirely different.
  • IANAC (cosmologist) and my last physics class was over 30 years ago, so bear with me.

    From TFA:

    "...the universe is instead about 15.8 billion years old and about 180 billion light-years wide."

    If I just think in terms of poor old antiquated Euclidean 3-space, and accept that C is as fast as you can go, then doesn't that make the universe's size about 150 billion LY at birth?

    That doesn't square much with the idea of a point-source Big Bang. Or is there some space warp voodoo going on here that I'm mi

  • by scovetta ( 632629 ) on Monday August 07, 2006 @09:57AM (#15858607) Homepage
    (from: http://www.space.com/scienceastronomy/mystery_mond ay_040524.html [space.com])

    This article generated quite a few e-mails from readers who were perplexed or flat out could not believe the universe was just 13.7 billion years old yet 158 billion light-years wide. That suggests the speed of light has been exceeded, they argue. So SPACE.com asked Neil Cornish to explain further. Here is his response:

    "The problem is that funny things happen in general relativity which appear to violate special relativity (nothing traveling faster than the speed of light and all that).

    "Let's go back to Hubble's observation that distant galaxies appear to be moving away from us, and the more distant the galaxy, the faster it appears to move away. The constant of proportionality in that relationship is known as Hubble's constant.

    "One seemingly paradoxical consequence of Hubble's observation is that galaxies sufficiently far away will be receding from us at a velocity faster than the speed of light. This distance is called the Hubble radius, and is commonly referred to as the horizon in analogy with a black hole horizon.

    "In terms of special relativity, Hubble's law appears to be a paradox. But in general relativity we interpret the apparent recession as being due to space expanding (the old raisins in a rising fruit loaf analogy). The galaxies themselves are not moving through space (at least not very much), but the space itself is growing so they appear to be moving apart. There is nothing in special or general relativity to prevent this apparent velocity from exceeding the speed of light. No faster-than-light signals can be sent via this mechanism, and it does not lead to any paradoxes.

    "Indeed, the WMAP data [on cosmic microwave background radiation] contain strong evidence that the very early universe underwent a period of accelerated expansion in which the distance been two points increased so quickly that light could not outrace the expansion so there was a true horizon -- in precise analogy with a black hole horizon. Indeed, the fluctuations we see in the CMB are thought to be generated by a process that is closely analogous to Hawking radiation from black holes.

    "Even more amazing is the picture that emerges when you combine the WMAP data with [supernova] observations, which imply that the universe has started inflating again. If this is true, we have started to move away from the distant galaxies at a rate that is increasing, and in the future we will not be able to see as many galaxies as they will appear to be moving away from us faster than the speed of light (due to the expansion of space), so their light will not be able to reach us."

    • by wisebabo ( 638845 ) on Monday August 07, 2006 @10:34AM (#15858839) Journal
      I believe that the 180B light years is just a MINIMUM, that is the universe could actually be much much larger. The 180B lyrs. would the minimum size that would be allowable under our current measurements (for example the cosmic background radiation) that dictate how much the universe grew as a result of "inflation". It it were smaller than that, we would start to see "reflections" of ourselves as the light in the universe would have gone all the way around like in a hall of mirrors (and we could see the earth of a long time ago!).

      To illustrate how big the universe could be there was, I think, an interesting article (set of articles?) in Scientific American that described the various ways in which we would could have a "parallel (viewable) universe" to our own. One was the idea that the whole universe was so huge that if you went far enough you could find an exact same configuration of all of the particles that we can see in our own viewable (~30B lyr wide) universe.

      Of course this would mean that the actual universe would be so unbelievably gigantic that 180B lyr. would be an unimaginably tiny speck within it!

  • 15% Slower (Score:5, Funny)

    by Anne_Nonymous ( 313852 ) on Monday August 07, 2006 @10:00AM (#15858623) Homepage Journal
    > the universe is...about 180 billion light-years wide...and 15% slower

    Yeah well, I'm a little wider and a bit slower each year too.
  • Erdos joke (Score:5, Interesting)

    by rothlmar ( 982182 ) on Monday August 07, 2006 @10:00AM (#15858624) Homepage
    The prolific mathematician Paul Erdos, towards the end of his life, used to say that he was about four billion years old. He explained: when he was a boy, the known of the age of the universe was about five billion years, but by the time he was older, the age of the universe was had grown to nine billion. Tack on another billion and change for all of us...
  • Up until five years ago there was a factor of two discrepancy- the Hubble constant using supernova candles gave a young age; globular cluster star ages appeared about 20 billion. The high resolution microwave background variance measurement agreed with the Hubble number, so that is currently the best hypothesis.
  • only a 10% story (Score:3, Insightful)

    by bromoseltzer ( 23292 ) on Monday August 07, 2006 @10:03AM (#15858649) Homepage Journal
    15.8 is not "much older" than 14.3 billion years. It's only about 10% older. This is just a tweak. For a long time, astronomers disagreed about the Hubble age by a factor of two or more, and probably some still do.
  • by dzfoo ( 772245 ) on Monday August 07, 2006 @10:04AM (#15858655)
    AP 08/07/2006, Jordan - In related news, a new scroll has been uncovered in the Dead Sea that categorically insists that God most definitely did *NOT* rest on the seventh day, and perhaps worked on the Creation at least half-way through the next week. The Universe is now believed to be 9 1/2 days old; a full 3 days older than originally thought.

            -dZ.
  • by StupendousMan ( 69768 ) on Monday August 07, 2006 @10:09AM (#15858677) Homepage

    This whole article is misleading. The new research has very little to do with our knowledge of the size and age of the universe.

    (And, yes, I am an astronomer).

    Stanek and company have used measurements of one eclipsing binary system to determine the distance to M33. This is a good way to measure distances, as it avoids the perils of even a short "ladder" of methods. They find a distance modulus of 24.92 +/- 0.12 mag to the binary. You can read their paper on astro-ph at

    http://xxx.lanl.gov/abs/astro-ph?papernum=0606279 [lanl.gov]

    Go to Table 7 of their paper, in which they compare their distance to previous measurements. There are 12 previous values, measured by several techniques (only 2 of the papers use Cepheids). The range of those previous values is 24.32 +/- 0.45 to 24.86 +0.07/-0.11. Their new distance is inconsistent, at the 1-sigma level, with 6 of the 12 others; thus, it is consistent with 6 of the 12 others.

    Yes, it's true that the HST Key Project distance to M33, computed using Cepheids, is smaller than the new distance by an amount well outside the quoted uncertainties. But that's not a big deal, by itself. M33 is only one of a number of galaxies which serves to calibrate secondary distance indicators, which may in turn be used to find the Hubble constant. A small change in the distance to M33, even if true, would not make any major change to H-nought.

    Recall that M33 is close enough to us that its radial velocity is NOT caused by the expansion of the universe, but instead by the gravitational forces of the galaxies in the Local Group. The press release's statement

    The team's results suggested that the stars were about 3 million light-years from Earth--or about half-a-million light-years farther than would be expected using the commonly accepted Hubble constant value.

    is absolute nonsense. One cannot USE the Hubble constant and radial velocity of M33 to calculate its distance. The radial velocity of M33 is -179 km/sec, so "using" the Hubble costant to determine its distance would yield a negative distance. Phht.

    This is a very nice, and very very worthwhile scientific project -- I have followed the DIRECT team's efforts for years, and encourage them to keep going! -- but the press release tries too hard to make it into some sort of breakthrough with profound immediate results.

    Sigh.

  • by tjwhaynes ( 114792 ) on Monday August 07, 2006 @10:12AM (#15858700)
    I love it when I see reports like this. Stating that the age of the universe is 15.8 billion years old gives the impression that this is accurate to around 1 percent or better. The error bars on this sort of figure are probably closer to +/- 2 billion years or more, implying that the 99% percentile answer is something in the range 12 - 20 billion years. Most of the "measurements" over the last 20 years fit into that range. There is a tendency for the more recent publications to fall into the 14 - 16 billion year mark and that may simply be a reflection that that is the "accepted" answer.

    I actually used to work on a team measuring the Hubble Constant using Radio Telescope data ten years ago - actually the same group who came up with 42 km s-1 Mpc-1 value which caused all the Douglas Adams H2G2 references (that was shortly before I joined). There was a lot of controversy over the value of the Constant back then and it is still a hot topic. Back then, the Hubble Constant was thought to have values anywhere from 30 km s-1 Mpc-1 up to 120 km s-1 Mpc-1 . The smaller the value of the Hubble Constant, the older the Universe is. Having a smaller value was desirable because it meant that the Universe was old enough to account for the oldest objects observed (about 16 billion years old). Think about that.

    One of the points that struck me then was that the value of the Hubble Constant measured tended to be higher when measured using "more local" techniques and tended to be lower as techniques using more distant measurements were used. The Radio Telescope information gave us measurements based on object around or beyond a redshift of 1 (or, to put it another way, these clusters of galaxies observered were about half the age of the universe when the light left them).

    Anyway, we'll be seeing more measurements of the Hubble Constant for many more years. Just remember the error bars!

    Cheers,
    Toby Haynes

    • by habig ( 12787 ) on Monday August 07, 2006 @11:43AM (#15859230) Homepage
      Stating that the age of the universe is 15.8 billion years old gives the impression that this is accurate to around 1 percent or better. The error bars on this sort of figure are probably closer to +/- 2 billion years or more, implying that the 99% percentile answer is something in the range 12 - 20 billion years.

      No, the startling thing about recent cosmological work is that we do know this number to ~percent. The flagship for this new "precision cosmology" are the WMAP [nasa.gov] results [nasa.gov]. The number is weighing in at 13.7+/-0.2 billion years. Take a look at the tables of cosmological parameters in this paper and the carefully calculated error bars.

      This particular press release's sweeping claims do overreach, as nicely summarized by Michael Richmond in a post above. M33 isn't at a cosmological distance, the observations being done by this project help to understand the lower rungs of the distance ladder, from which you can figure out distances to far-off galaxies and try to calculate numbers to independently compare to the microwave background fits. These results are one of many such distance calibrations, and have to be factored in statistically with the others. On the whole, several other means of figuring out cosmological parameters (such as the Age of the Universe) agree with the WMAP results within errors. You only get TFA's 15% increase if that is the only measurement you use to calibrate distances, throwing out all the rest.
      • by tjwhaynes ( 114792 ) on Monday August 07, 2006 @12:37PM (#15859614)
        No, the startling thing about recent cosmological work is that we do know this number to ~percent. The flagship for this new "precision cosmology" are the WMAP results. The number is weighing in at 13.7+/-0.2 billion years. Take a look at the tables of cosmological parameters in this paper and the carefully calculated error bars.

        Chewing through that paper (interesting one by the way) shows that those error bars are based on analysis of the data after processing. Therefore, those error bars on the age of the universe are assuming that the removal of foreground sources and fluctuations due to the Sunyaev Zel'dovich effect have been done absolutely correctly. No attempt (that I can see) has been made to model the errors arising from that procedure. That alone suggests that there are systematic effects which are not accounted for in those results.

        I'm extremely sceptical of a lot of error bars on a lot of data. Confusion is a huge topic in radio astronomy (and I don't mean the chaotic, running-around, headless-chicken type of confusion) and I see paper after paper that really doesn't understand it, deal with it or present any full explanation of how errors in confusion analysis would propagate into the answers.

        Cheers,
        Toby Haynes

  • by Archon_de_Gaul ( 639893 ) on Monday August 07, 2006 @10:14AM (#15858712) Homepage
    So would this larger, older Universe affect the need for the particular volume of Dark Matter we've been searching? If this value is accepted, do we need less Dark Matter to explain the current state of universal expansion and possible contraction? What does this do for the various theories, a-la 'steady state', et. al?
  • by ExE122 ( 954104 ) * on Monday August 07, 2006 @10:33AM (#15858834) Homepage Journal
    I don't want to get flamed by saying people are asking dumb questions, but everyone just needs to stop relying on simple arithmetic when dealing with the size of space... The concepts involved are far more complicated than that.

    One thing people don't seem to be grasping is that with the Big Bang model, the size of the universe isn't measured by the distance between two particles floating on the "edge". It is actually a measure of the width of the "fabric" of the known universe, space-time. Its difficult to grasp this since it is not something easily perceived.

    The real reason for the size of the universe being so much larger is that the laws governing the size of space-time are not the same as the laws of spacial relativaty, and therefore are not constrained to the upper bound of the speed of light.

    The best analogy that I've heard is the ant on the balloon example. The idea is that you picture an ant sitting on a balloon with a bread crumb an inch away. If you were to blow up the balloon to twice its size, the bread crumb wouldn't necessarily move to a distance of two inches from the ant.

    In this example, we are the ants and we are watching the galaxies, represented by the bread crumb, moving away from us. However, the fabric of existence is expanding at a much larger rate.

    The "what's beyond the edge" question is essentially a pointless question when dealing with space-time. There is no "edge" because nothing can possibly exist outside of the realm of spacetime.

    And if that concept doesn't satisfy the question, then a simple-minded answer would be that an "edge" can never be reached as space-time is always expanding faster than any particle could possibly hope to keep up with it.

    --
    "A man is asked if he is wise or not. He replies that he is otherwise" ~Mao Zedong
  • by qcomp ( 694740 ) on Monday August 07, 2006 @10:40AM (#15858885)

    The preprint of ApJ article is on the ArXive [arxiv.org], entitled The First DIRECT Distance Determination to a Detached Eclipsing Binary in M33 [arxiv.org].

    I guess this shows that numbers like the age of the universe should always be quoted with the current error bars. As far as I understand the new value is still within the uncertainty of currently accepted estimate. To have reduced the error from "a factor of 2" to below 15% within the last decade or so seems pretty good to me.
  • by FellowConspirator ( 882908 ) on Monday August 07, 2006 @11:04AM (#15859005)
    What then is the prevailing theory as to the disconnect between the 180 billion light year size and the 15.8 billion year age. If the universe was born out of a massive explosion 15.8 billion years ago, it would have had that long to spread out at the speed of light in every direction. So, then, you'd have a sphere with a radius of 15.8 billion light years that defines the maximum size of the universe.

    So, the universe is 148.4 billion light years bigger than it ought to be (if the universe expanded from a singularity at the speed of light). So, do we believe the universe is expanding at much faster than the speed of light? Was space-time warped by the explosion? And if so, how can any guess made on spectral/telemetry data be considered meaningful?
  • by carpeweb ( 949895 ) on Monday August 07, 2006 @11:14AM (#15859057) Journal
    My brain hurts.

    So far, all the answers to all the questions seem to be making the same implicit assumptions:
    1. Hubble's Constant is constant
    2. The current size of the universe is known
    I'm sure there are many equally important assumptions, but these two seem to form the basis for using the inverse of H-nought (dang, I'm British, now!) to calculate the age of the universe.

    If Hubble's Constant is actually Carpe Web's Variable (dang, I'm important, now!), then we'd have to know all the values of CW-i (index of Carpe Web's Variable over time, formerly thought to be Hubble's Constant) and then take one mother of an integral to calculate the age of the universe. Well, if we were smart enough to know all the values of CW-i over 6,000 years -- oops, I mean 15.8 billion years -- then maybe the integral wouldn't be too difficult.

    But, we'd still need to know the current size of the universe to calculate the age. What if there's a little bit more beyond what we can currently "see"? What if there's some schmutz on the lens of the Hubble telescope? What if the invisible pink elephants only look invisible but are actually blocking our "view" of the real edge of the current universe (or maybe the edge of the universe 15.8 billion years ago, which is when the light from it started on its path to us)?

    Anyway, my brain hurts, but either of the assumptions seems to swamp the margins of error mentioned in this thread.
  • by Drathos ( 1092 ) on Monday August 07, 2006 @11:19AM (#15859090)
    The Hubble Constant - Fluctuating since 1929
  • more detail (Score:4, Informative)

    by gsn ( 989808 ) on Monday August 07, 2006 @11:31AM (#15859150)
    There are several posts that mention that the universe can expand faster than light. They are right but let me see if I can expand on it some.

    If you have taken a fair bit of math skip this and and go here http://pancake.uchicago.edu/~carroll/notes/ [uchicago.edu] to Chapter 8 in particular.

    We want the universe on the largest of scales to look isotropic and be homogeneous spatially. The first means it looks the same in all directions about some point, and the second meaning that its physical properties are the same everywhere. If the universe is isotropic about one point and it is homogeous it follows that it is isotropic about every point. Straight away there is no priveleged center and it is meaningless to talk about the center of the Big Bang or some such. Insert standard dots on a balloon or raisn bread rising explanation here but neither is perfect.

    We can look at galaxies and can see spectral lines and can measure their shifts and recognize that they must be moving with respect to us, and are typically moving away from us so the univsere is expanding. So the universe must look the same from every point in space but it is not static and can look different at different times. Because we want to maintain homogeneity and isotropy through time and because we believe there are no privleged directions or points in space we want this expansion to be solely a function of time. This function of time is what is called the scale factor and it is the fundamental quantity that determines what present distances in the universe are and how fast they are changing. There is no speed of light anywhere around the scale factor, and there isn't going to be.

    With all this we can write down the model for the universe, and its called the Friedmann-Lemaitre-Robertson-Walker metric after the smart people who came up with it. Thats fancy talk for a single line that tells you how to compute the "distance" between two events each occuring at their own space and time coordinates. Its equation 8.7 in the article. If you believe we live in a flat universe which you should because theres lots of good experimental evidence for it from studying the cosmic microwave background, even that simplifies a fair bit to something that can look like ds^2 = dt^2-a^2(t)(dx^2+dy^2+dz^2).

    The second section in brackets to the right of the scale factor is the way you'd compute the distance between two events in 3d space, just the sum of the squares of their differences in position, and the dt^2 is the bit that adds on time. In any local region of the universe a(t) is constant and can be taken to be one and then you have a return to happy special relativity where the speed of light is constant to all inertial observers. Take a(t) to zero and you see the singularity in the equations which we call the Big Bang. This is where the model and the equations break down and thats all we can truly say about it. The universe (hopefully) does not break down, only our model to describe it does.

    This metric, which we can write happily as a diagonal matrix even can be plugged into Einsteins equations and give you yet more equations like the Friedmann equation and the acceleration equation (Carroll 8.35 and 8.36), and you can derive Hubbles law and discusses all the interesting forms of matter you can have in it including what happens in Einstein's equation has a cosmological constant term. You'll notice theres still no speed of light. Stuff in the universe cannot move faster than the speed of light according to some local observer. However, the universe is sort of the fabric on which all the stuff is and that fabric can stretch faster than the speed of light. We do see object moving faster than light. See near end for an example, more information and no serious equations http://www.astro.ucla.edu/~wright/doppler.htm [ucla.edu]

    Thats become somewhat important following the studies of distant supernovae from '98 and we now know that the univer

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