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How Big Was the Universe When It Was First Born?

Posted by timothy on from the that's-gotta-be-some-afterbirth dept.

StartsWithABang writes: Looking out at the distant stars, galaxies and radiation in the Universe today, we've been able to determine not only what it's made out of, but how long it's been since the Big Bang: 13.8 billion years. Put all that information together, and you can also figure out how large the observable part of that Universe is today. From our point of view, it appears to extend for 46.1 billion light years in all directions. So what if you extrapolate backwards, to the very end of inflation and the start of the hot, dense state we identify with the Big Bang, and ask how large that 46.1 billion light year "size" was back then? How big would it be? Depending on the particulars of when inflation came to an end, the answer is somewhere between the size of a soccer ball and the size of a city block, no smaller and no larger.

26 of 194 comments (clear)

  1. Article blocked by arth1 · · Score: 4, Informative

    Can't read TFA. Does anyone got a link to an article that isn't behind an anti-adblock page?

    IInformation wants to be free. It's part of cosmic entropy.

    1. Re:Article blocked by Z00L00K · · Score: 2, Informative

      Size of a football for us that aren't North American.

      --
      If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
    2. Re:Article blocked by Rob+Lister · · Score: 2

      Maybe it is a blessing in disguise. Why would one go to Forbes to read a science article?

    3. Re:Article blocked by AK+Marc · · Score: 5, Informative

      Soccer is a British term, invented by the English. That the Americans use "proper" British English and the English don't is ironic. Soccer was short for Association Football. Rugger for Rugby Football. Football wasn't used because it was a class of sport (any sport played on foot - i.e., not no horseback). So Soccer and Rugger were the British English words for those sports. Neither is in widespread use today.

      By the time the word was adopted by other counties, futbol and other spellings of football made more sense, as Rugger didn't get as much play, so football was re-translated into English from non-English who adopted it from English. And for England's misuse of language, the US is held as the odd man out for using the more proper term.

      Much like aluminum and aluminium. England got that one wrong as well. An Englishman named it Aluminum, as it was alum-like, but he didn't want the regular -ium as it wasn't a metal (it's a transition element that's semi-metalic), so he deliberately mis-named it, but this proper name assigned by the discoverer was ignored (in violation of convention) by the English and renamed. So the English re-named an element appropriately named by the disvoverer, who was also English. So the proper English name is Aluminum (as it was named such by the discoverer, who was an Englishman), but used incorrectly, to this day, by the English, who insist that their error is more correct that the American's non-error.

      --
      Learn to love Alaska
    4. Re:Article blocked by Anonymous Coward · · Score: 2, Informative

      Absolute nonsense. Have you ever noticed that the 'soccer' clubs in the UK are called "XXXX FC"? The FC stands for "football club". 'Soccer' was actually so named by a bunch of posh private school kids to dissociate it from rugby football, which arose as an offshoot of football at the Rugby school.

      The rest of what you say about sports not played on horseback is also complete horse shit. Cricket has been cricket for as long as it's existed. Likewise baseball, basketball etc.

    5. Re:Article blocked by mark-t · · Score: 4, Informative

      Much like aluminum and aluminium. England got that one wrong as well. An Englishman named it Aluminum, as it was alum-like, but he didn't want the regular -ium as it wasn't a metal (it's a transition element that's semi-metalic), so he deliberately mis-named it, but this proper name assigned by the discoverer was ignored (in violation of convention) by the English and renamed. So the English re-named an element appropriately named by the discoverer, who was also English. So the proper English name is Aluminum (as it was named such by the discoverer, who was an Englishman), but used incorrectly, to this day, by the English, who insist that their error is more correct that the American's non-error.

      At the time that Humphrey Davy discovered the element, in 1825, the convention was still relatively new, and it is possible that Davy had not yet really known about it when he first named the metal. There was no lack of ancient names of metals that ended in -um, and not -ium (argentum, aurum, cuprum, ferrum, hydrargyrum, plumbum, and stannum). Further, in even the few decades leading up to the metal's discovery, several English metals were quite recently named that did not use the "-ium" convention, molybdenum, platinum, and tantalum. Finally, the metal lanthanum was not discovered until 1837, over a decade later, but its discoverer did not try to follow the "-ium" convention either. "Aluminum" is hardly alone. The "-ium" suffix convention has been universally followed for all elements discovered since.

      For what it's worth, Davy himself later decided to change its name from "Aluminum" to "Aluminium" to try and keep with the convention that was being adopted, substantiating the notion that when he had originally named it, he was simply not yet aware of that convention. Even the element now known Berylium had also been renamed from its original "-um" ending in the same decade (it was originally called glucinum), so such renaming is hardly a unique case even for its period. I do not know why the latter name change was internationally accepted while the former was not.

      --
      File under 'M' for 'Manic ranting'
    6. Re:Article blocked by arth1 · · Score: 2, Insightful

      Like the C in CCCP stands for "union" (well, the first one).

      There is no "CCCP". Unless you use the Cyrillic letters, it's written SSSR. With slashdot not accepting other character sets than ISO-8859-1, the transliteration of Cyrillic Es and Er are to Roman S and R.
      Writing CCCP is as wrong as writing MOCKBa.

      100 years ago, every sport played off horseback was "football".

      Like golf, cricket, croquet, boxing, wrestling, handball, water polo, darts... All football!

      Were we a wee bit liberal with the bottle of holiday cheer this year?

  2. Re:I'm a bit skeptical by Z00L00K · · Score: 5, Funny

    In the end we will figure out that someone divided by zero and the universe accidentally came to be.

    --
    If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
  3. Refers to Observable Universe Only by Anonymous Coward · · Score: 4, Insightful

    Note that this is only talking about the portion of the original the universe that became today's observable universe. There's absolutely no reason to believe that the size of the observable universe is the size of the total universe (and we happen to be at the very dead center of it.)

    There is good reason to believe that the universe is far far larger than the observable universe, and it may even extend infinitely in all directions, for all we know. Measurements on the curvature of the universe make that a plausibility.

    1. Re:Refers to Observable Universe Only by Anonymous Coward · · Score: 2, Interesting

      You've managed to argue that a definitely finite 2-d surface is infinite. The infinite surface would be mapped onto a flat plane.

      The relevant 3-d surfaces are hyperspheres, flat surfaces, and hyperboloids (ie saddles). The first is definitely finite, the other two ae infinite pending any further topological assumptions. However, a flat surface can still lead to a finite universe for a given topology, the simplest and most common example being a torus; this looks like Pacmanland, given that if you walk in any direction you get wrap round.

      It's worth noticing that as a local theory, general relativity (and indeed all metric theories of gravity) says nothing about global topology.

    2. Re: Refers to Observable Universe Only by 0dugo0 · · Score: 2

      [1] Astrostatistics and Data Mining
      pp13. Luis Manuel Sarro, Laurent Eyer, William O'Mullane, Joris De Ridder .. ISBN 1461433231, 9781461433231
      [2] Applications of Bayesian model averaging to the curvature and size of the Universe
      Vardanyan, Mihran; Trotta, Roberto; Silk, Joseph .. Monthly Notices of the Royal Astronomical Society: Letters, Volume 413, Issue 1, pp. L91-L95.

  4. Feature request by thegarbz · · Score: 2

    Please slashdot, please let us block posts by submitter not just by editor. PLEASE. This shit is becoming unbearable.

  5. "..Able to determine.." ORLY? by BlueStrat · · Score: 3, Informative

    Looking out at the distant stars, galaxies and radiation in the Universe today, we've been able to determine not only what it's made out of, but how long it's been since the Big Bang: 13.8 billion years.

    Umm, not so much.

    Might want to check out other theories like ones that incorporate quantum theories.

    http://phys.org/news/2015-02-b...

    "(Phys.org) - The universe may have existed forever, according to a new model that applies quantum correction terms to complement Einstein's theory of general relativity. The model may also account for dark matter and dark energy, resolving multiple problems at once.

    The widely accepted age of the universe, as estimated by general relativity, is 13.8 billion years. In the beginning, everything in existence is thought to have occupied a single infinitely dense point, or singularity. Only after this point began to expand in a "Big Bang" did the universe officially begin.

    Although the Big Bang singularity arises directly and unavoidably from the mathematics of general relativity, some scientists see it as problematic because the math can explain only what happened immediately afterâ"not at or beforeâ"the singularity.

    "The Big Bang singularity is the most serious problem of general relativity because the laws of physics appear to break down there," Ahmed Farag Ali at Benha University and the Zewail City of Science and Technology, both in Egypt, told Phys.org."

    Strat

    --
    Progressivism (aka US 'Liberalism'): Ideas so good they need a police/surveillance-state to enforce.
  6. Re:Why would our universe be special? by Psychotria · · Score: 2

    Why would our universe be special? Who is to say that "our" universe it not the only universe? And, in that case, special compared to what?

  7. Re:Black hole by stevelinton · · Score: 2

    One answer to this is that the rest of space was equally packed with mass, so the gravitational pull on each parfticle was more or less balanced.

    Another is that nothing has escaped. We're still there, it's just strectched. To use a very weak analogy, if you are trapped inside a balloon as it is being inflated you have more room to move around, but are still trapped.

    Still another answer is that space itself was expanding.

  8. Re:Bull + Shit by Opportunist · · Score: 2

    Science does not know everything.

    Religion does not know anything.

    --
    We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
  9. Re:questions by Opportunist · · Score: 2

    Because yes, you cannot move in space faster than the speed of light, but space itself expanding faster than the speed of light does not break that law. That is, admittedly, not easy to grasp and frankly I doubt that I have enough of a grasp of it to explain it sensibly.

    The problem starts with all the shows that "show" you the big bang in some artist rendition: From the outside. There is no outside to the big bang as far as we are concerned because everything we know about is inside of what the big bang started. Think of it as sitting inside of a balloon that slowly gets inflated. You can move inside the balloon, with the balloon itself not moving but expanding.

    --
    We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
  10. Use the source, Luke by Opportunist · · Score: 4, Informative

    Allow me to link to the non-Forbes, non-ad-infested, non-ad-blocker-blocking version of the article: http://scienceblogs.com/starts...

    --
    We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
  11. Re:I'm a bit skeptical by dskoll · · Score: 2

    Whoever published it must have quite a pair of brass balls.

    Yes, and they're each somewhere between the size of a soccer ball and a city block.

  12. Hypothesis plus Measurements makes science by Geoffrey.landis · · Score: 2

    you're no better or more accurate than religious beliefs.

    They definitely are.

    They are better or more accurate than religious beliefs if, and only if, their work can make predictions about things that can be measured.

    Conventional big-bang cosmology definitely did make testable predictions: the cosmic microwave background; the isotope ratio of elements formed by nucleosynthesis in the high density plasma of the early part of the big bang.

    Whether inflationary cosmology--or the even more speculative landscape cosmologies-- will make similar predictions is still somewhat open. Right now inflationary cosmology does have one success; it predicts the isotropy of cosmic background radiation even from regions causally disconnected in the early universe. It's hard to find another hypothesis that also makes this prediction, so inflation is getting to be pretty well accepted as a baseline, at least until some better model comes along that also fits the data. But there are many people looking for that better model.

    --
    http://www.geoffreylandis.com
  13. Re:Black hole? by Geoffrey.landis · · Score: 2

    Very cool, but got me wondering... So how come the gravitational force didn't collapse it into a black hole?

    Another very tricky question. The answer is not very satisfying: the Schwartzschild solution ("black hole") is a spherical gravitational field embedded in flat ("Minkowski") space, but the universe itself isn't embedded in flat space; it is space (and it's also not flat).

    In simplified form, a black hole has to have an "outside" to be defined in relationship to. The black hole is defined by the event horizon, a surface beyond which light can't escape... but you can't have such a surface unless there exists a "beyond".

    You can, if you like, say that the entire universe is a black hole, in that-- by definition-- light can't escape from it.

    --
    http://www.geoffreylandis.com
  14. Big Bang is Science by Roger+W+Moore · · Score: 2

    The second problem is the Big Bang Theory is not-even-Science -- there is no way to replicate or reproduce the experiment!

    I completely agree with your assessment of the one you colourfully name "Starts-With-A-Shit" since he gets his particle physics wrong all the time too. However I have to disagree with your assessment of the Big Bang Theory.

    For a start it has made several predictions which have turned out to be correct: the relative abundances of the elements in the Universe and the cosmic microwave background. Secondly it is partly reproducible in the Large Hadron Collider in that we can recreate the conditions of the early universe to figure out the physics and then make predictions on how the universe would look today if it had started in a Big Bang.

    There are still some unknowns such as Dark Matter and how the matter/antimatter asymmetry came about but that is one way to test the model: if we find that the physics behind these is incompatible with the Big Bang then we will have falsified the model. Hence since it makes predictions, is falsifiable and is partly reproducible it is hard to argue that it is not science.

  15. Fuck Forbes by AndyKron · · Score: 3

    Fuck Forbes. Fuck them to all fucking hell Don't EVER link to those motherfuckers again!

  16. Re: I'm a bit skeptical by qeveren · · Score: 2

    1. You are ignoring causality.
    2. You are ignoring the speed of gravity (which is very likely c).
    3. You are ignoring the fact that nerve induction doesn't work all that quickly.

    --
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    Add this as a userscript for slashdot.org

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    Add UserCSS, e.g. with Stylish:

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  18. Re: I'm a bit skeptical by ceoyoyo · · Score: 3, Informative

    1) The whole requiring infinite energy to even get up to c part makes it a little tricky to go faster.

    2) Your link is BS. It seems to be talking about some theoretical results from general relativity but completely misinterprets them and also presents them as experimentally verified. Actual experiments have measured the speed of gravity to within 1% of the speed of light: https://en.wikipedia.org/wiki/...

    3) ???