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How Big Was the Universe When It Was First Born? 194

Posted by timothy 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.
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How Big Was the Universe When It Was First Born? More

How Big Was the Universe When It Was First Born?

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  • Article blocked (Score:4, Informative)

    by arth1 ( 260657 ) on Sunday December 27, 2015 @04:38AM (#51189173) Homepage Journal

    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.

    • Re: (Score:3, Informative)

      by Z00L00K ( 682162 )

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

      • Re: Article blocked (Score:1)

        by Anonymous Coward

        ...or Australian. A football here is either an AFL ball or a rugby ball.

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

          Same.

          An association football ("soccer") ball is 22-23 cm in diameter

          An American football ball is 28 cm from tip to tip on the long axis, and 18 cm in diameter.

          This article is about order of magnitude, and these two numbers are identical to well within order of magnitude.

          http://www.football-bible.com/... [football-bible.com]
          http://www.livestrong.com/arti... [livestrong.com]

        • That's not quite true. In Australia, "football" may refer to Australian rules, rugby league, rugby union, or soccer. However, only the first two of these may be referred to as "footy".

          (Obligatory Australian joke. Q: What's the difference between a kangaroo and a wallaby? A: One plays rugby league, the other plays rugby union.)

      • Re:Article blocked (Score:5, Informative)

        by AK Marc ( 707885 ) on Sunday December 27, 2015 @06:58AM (#51189479)
        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.

        • Re:Article blocked (Score:5, Informative)

          by mark-t ( 151149 ) <markt AT nerdflat DOT com> on Sunday December 27, 2015 @12:58PM (#51190477) Journal

          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.

        • But aluminum is a metal, so...?

    • Maybe it is a blessing in disguise. Why would one go to Forbes to read a science article?
    • Try: http://www.forbes.com/sites/st... [forbes.com] Still the forbes site, but it seem to bypass the anti-adblock page.
    • Don't use ad-blocker. use noscript then you can get in but without all the troll-ware. Allow the forbees site and it's data server to see content. Static ads normaly show but they need to source their own ads since the remote links are blocked via the script blocker.

  • Refers to Observable Universe Only (Score:4, Insightful)

    by Anonymous Coward on Sunday December 27, 2015 @04:55AM (#51189217)

    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.

    • When you think about it the measurement is always totally wrong. For one the measure stick is inside the universe and is thus incapable of measuring itself. Some things you just have no reason to know and this is one of them.
      Time is also a relative factor in the universe so it too is not measurable and it is slowing down. Our brains being time-wise inter-spacial perceive it as speeding up.
      It's that Timey Whimey thing "Dr Who * BBC"
    • I read a book once with a good thought experiment to think about the size and shape of the universe. It helps to first imagine a 2d space with similar qualities...

      What 2d space is "infinite" and what does it look like? Well, look no further than the earth - the surface of our planet is two dimensional, though if you were to point yourself in any direction and start walking, you would eventually end up where you started. If you had no other frame of reference (eg could go into space and look at the pla

      • Re: (Score:2, Interesting)

        by Anonymous Coward

        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 an

      • The surface of a sphere is *unbounded*, not infinite. There's a lot of overlap, but I'm not even sure you can say that all infinite things are unbounded.

  • Feature request (Score:3)

    by thegarbz ( 1787294 ) on Sunday December 27, 2015 @04:55AM (#51189219)

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

    • Hm yes. Ethan has begun to publish on Forbes, and wants it to be known urbi & orbi. This is becoming annoying. OTOH, do not expect your feature request to be honoured. Not in these days. In the early /. days, it might have been. You're coming about 15 years late, alas.

    • Add this as a userscript for slashdot.org

      var writers = document.querySelectorAll('div.body > div.p > a[href^="/~"]');
      for (var writer of writers)
      {
      if(writer.innerHTML == "StartsWithABang")
      writer.parentElement.parentElement.parentElement.classList.add("HideThisCrap");
      }

      Add UserCSS, e.g. with Stylish:

      .HideThisCrap { display:none; }

  • "..Able to determine.." ORLY? (Score:4, Informative)

    by BlueStrat ( 756137 ) on Sunday December 27, 2015 @05:19AM (#51189289)

    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]

    "(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

    • There are other theories. TFA is rooted in inflation theory in which there is also no singularity -- the "modern:" universe condensed from an inflating universe with quite different properties as a very hot very dense expanding space. A ball of that a few cm or m across has eventually become our entire observable universe.

      The theory you reference is in the very early stages of theoretical physicists playing with mathematical theories. Which is fine, but quite a bit of progress would be needed before it got

  • If you have a lot of mass in a small enough space, the gravitational pull of the mass creates a black hole. If all the "stuff" in the universe was in such a small space, then how do you get an expanding universe? You should have a black hole from which nothing will ever escape.

    • 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.

    • Re: (Score:2)

      by PPH ( 736903 )

      Space from which point of view? Inside the black hole or outside of it. It's possible that, from the outside of our universe (outside it's even horizon), it's radius s fixed by it's mass. Inside the even horizon, 'space' might be changing over time (indeed 'time' may change over time) to give the appearance of expansion.

  • Surely if all 'size' was in there, it was as 'big' as it is. The metric was changing then, just as it is changing now.

  • Use the source, Luke (Score:5, Informative)

    by Opportunist ( 166417 ) on Sunday December 27, 2015 @09:18AM (#51189797)

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

  • The more important question, of course, is not "how big was the universe when it was first born," but "what gave birth to the universe?"

    • Re: (Score:2)

      by PPH ( 736903 )

      More important to whom?

    • Re: (Score:2)

      by quenda ( 644621 )

      The more important question, of course, is "what gave birth to the universe?"

      No, that question makes no sense. If something "gave birth" it would be a part of the universe, and you be asking where that something came from.
      The universe must lift itself by its own bootstraps.

      It does not even make sense to say that the universe exists, because if you think about it, to exist means that an instance is located in our universe, or a subset of it, such as our planet. If the universe is everything, there is no context for it to exist in.

  • Our universe was a soccer ball sized weapon stored in a missile rack on one of the star cruisers of the high masters. It was fired at an enemy installation during the ieter-universal wars. Our universe is just the debris field that occurred after detonation.

  • Size of humans is right in the middle of that range.

  • I always thought inflation occurred after the Big Bang, not before it. Wonder where I got that idea...

  • Fuck Forbes (Score:4)

    by AndyKron ( 937105 ) on Sunday December 27, 2015 @02:16PM (#51190795)
    Fuck Forbes. Fuck them to all fucking hell Don't EVER link to those motherfuckers again!
  • The early Universe postulated by the big bang was low in entropy. Another way to say low in entropy is low probability! The probability that the matter and energy of the Universe organized itself into the form postulated is an extremely low number. I mean really really really really small! Take the smallest number you can think of and make it a gazillion time smaller than that!

    Now consider the probability that human beings made a fatal error in constructing the big bang theory. This number may be extre

    • Re: (Score:2)

      by xlsior ( 524145 )
      Don't forget that while the event may have been extremely unlikely, it also had a near(?)-infinite cosmological timescale to occur on. On top of that, we have a sample size of '1', this being the only universe we have actually observed ourselves.

    • I never trust statistical arguments that could have their meaning changed by a change of 1 to the number of events. In this case, subtracting 1 from the number of Universes observed nullifies that argument, not to mention all other arguments.

  • ...it was big enough to fill the entire universe. Even if it was the "size" of a mere soccer ball, there was no time or space beyond.
  • Yeah, the size of the universe is interesting from a purely academic standpoint but isn't it meaningless? I mean it's still the whole universe, right? Although toward the end of the article we have the implication that it WASN'T the entire universe - just what we can observe. So there may have been volume beyond the soccer ball. And if there was, does it matter? Does it affect our universe initial conditions?. And what's up with the superluminal expansion? And not just a little superluminal - it make
  • Okay. If the universe is 13.8 billion years old and the fastest stuff travels at the speed of light and the initial size of the universe is something "macro" in scale (between a soccer ball and a city block), then why isn't the universe 13.8 billion light years in diameter? Where does the 46.1 billion LY come from? Thanks!
  • Surely this goes against everything we know about the expansion of space time? When the universe expands, it not like an explosion where matter expands into space or void. The actual space itself stretches and thus the ruler with it. Not to mention there's nothing to expand into as the universe is the entirety of everything. This is true even if you take into account the size of the universe being bigger than what we see in the observable universe due to the event horizon. So a universe pre-inflation of 1

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