Comments on: Big Bang Baffles Bonzai

Question: Big Bang Baffles Bonzai

Bonzai — Wed, 20 Feb 2008 23:55:07 -0800

Why is the Big Bang possible?

I know that a black hole is formed when X amount of matter is in one place. I know that nothing (except Hawking radiation) can escape a black hole.

So if all the matter in the universe was once contained in a single point how could it have possibly escaped from all that gravity? Obviously it did, but ... how?

By: panamax

panamax — Thu, 21 Feb 2008 00:06:24 -0800

Simple answer: nobody knows.

By: flabdablet

flabdablet — Thu, 21 Feb 2008 00:06:32 -0800

It didn't escape. It's still here.

By: jmnugent

jmnugent — Thu, 21 Feb 2008 00:24:52 -0800

Maybe they'll find out when they turn the LHC "on" in May. :)

By: PercussivePaul

PercussivePaul — Thu, 21 Feb 2008 00:40:54 -0800

Wikipedia's got lots of cool articles along these lines, but it doesn't look like there is a generally accepted answer. I had fun jumping around through them all but it's way over my head. Any physical cosmologists in the house?

By: nicwolff

nicwolff — Thu, 21 Feb 2008 00:56:52 -0800

What matter "is" and how gravity applies at sub-Planck distances and super-Planck temperatures is not well-defined.

By: cgc373

cgc373 — Thu, 21 Feb 2008 01:20:19 -0800

Here's science writer George Johnson reviewing The Life of the Cosmos, Lee Smolin's speculative answer to your question, Bonzai. Smolin posits an expanded variety of natural selection on a cosmological scale to account for our universe's qualities. Untold, uncounted, probably unimaginable numbers of other universes don't allow their Big Bangs to happen as ours has, does, did, is, or whatever tense is needed to describe a universe in toto. Another accessible account of how our universe might have failed to work is Martin Rees's Just Six Numbers, which is summarized briefly here.

By: minifig

minifig — Thu, 21 Feb 2008 01:29:21 -0800

I think the answer has to do with the fact there's nothing else outside the pinprick of matter. Gravity is something that acts on space, and it wasn't as if the big bang happened within space, it created all space, and that's a very different kettle of fish.

By: Gary

Gary — Thu, 21 Feb 2008 01:47:30 -0800

Gravity is weak compared to the other possible forces at work (magnetic or nuclear, for example). So that might help answer the "escape" part of your question.

By: rainy

rainy — Thu, 21 Feb 2008 02:14:50 -0800

Big bang wasn't a black hole. As you probably know, theories don't go far enough to tell us what was before or right at the moment of big bang. The same goes for the black hole's insides. However that's the only thing in common - for one thing big bang wasn't surrounded by space, like black holes are. There was no 'outside' of big bang according to current theories. Or if there was, it's not something we understand. Big bang was some unusual process that created space, time, matter and dinosaurs; black holes are a dime a dozen even in any tiny portion of the space that was created by BB and they involve only a very tiny portion of matter that was created by BB, even the super heavy black holes in centers of galaxies. The only certain connection between the two is our ignorance of them.

By: edd

edd — Thu, 21 Feb 2008 02:33:56 -0800

I'd written an answer but then remembered John Baez had already done it here, and much better than I could have.

By: edd

edd — Thu, 21 Feb 2008 02:37:16 -0800

Excepting the caveats that Baez gives about whether the universe is truly homogenous, if I put not just x amount of matter in some small space, but fill space with that density of matter, where would you put the event horizon? That might help answer the question.

By: dragontail

dragontail — Thu, 21 Feb 2008 04:54:08 -0800

It is not know if the current laws of physics actually held at the big bang. Therefore, we cannot answer your question with authority without further evidence m'fraid.

By: ROU_Xenophobe

ROU_Xenophobe — Thu, 21 Feb 2008 05:26:10 -0800

So if all the matter in the universe was once contained in a single point how could it have possibly escaped from all that gravity?

I am not a physicist or cosmologist.

All the matter in the universe wasn't contained in a pre-big-bang kernel. At the instant of the big bang, there was no matter, not even subatomic matter. It was simply too hot for matter to exist. Instead, imagine all the matter in the universe, converted to energy by e=mc^2, and all of the other energy in the universe. That's what was in the fireball. AFAIK, at the instant of the big bang it was also too hot for gravity to exist as an independent force.

Matter didn't start to exist for a long, long time, like a few seconds or at least a large fraction of a second, and by that time the guesses are that the universe was at least one or a few light-years across.

IIRC, it's also the case that the energy and then matter didn't fly out into empty space. Instead, the big bang made space and inflated space, and space keeps inflating ("metric expansion").

By: edd

edd — Thu, 21 Feb 2008 05:37:25 -0800

Matter is there from the start, or near enough. We don't know much about the first tiniest fraction of a second but you very rapidly have stuff we've got a handle on. Plus radiation's gravitational effect has an effect too, and in fact is vastly more important early on than the effect of matter.

By: ROU_Xenophobe

ROU_Xenophobe — Thu, 21 Feb 2008 05:55:37 -0800

Huh? The various timelines I can dig up don't even have quarks until 1--3 seconds after.

By: edd

edd — Thu, 21 Feb 2008 06:06:29 -0800

This gives a timescale. Note that hadronization is about 170MeV, and that's already long gone after a fiftieth of a second.

By: ROU_Xenophobe

ROU_Xenophobe — Thu, 21 Feb 2008 06:59:57 -0800

Okay.

By: LionIndex

LionIndex — Thu, 21 Feb 2008 08:28:38 -0800

There's a book called "The First Three Minutes" that basically describes what edd and ROU are talking about, where the universe was basically all energy at the start, and then gradually became matter. It's a good book for explaining (at least one view of) the Big Bang.

By: weapons-grade pandemonium

weapons-grade pandemonium — Thu, 21 Feb 2008 09:08:09 -0800

A very small asymmetry is my guess. The tiniest contamination would do it. With large constrained forces you don't need much of a weak spot to break things wide open. Like lobbing a small porcelain shard at a sheet of tempered glass.

By: jamjam

jamjam — Thu, 21 Feb 2008 09:27:27 -0800

Oof, edd; that article is a steep hill.

Attempting it has given me the sense I can see a larger landscape, but I can't tell if it answers a question that's been bothering me: could the big bang have had non-zero rotation from the very beginning-- or even must it have had some rotation by the angular uncertainty principle? If the Big Bang can be seen as a white hole (a time reversed black hole) some angular momentum seems like it would be a natural part of that point of view.

By: hermitosis

hermitosis — Thu, 21 Feb 2008 09:58:15 -0800

For a metaphor that's easier to visualize, but not at all scientific, in the form of Jewish mysticism known as Kabbalah (not to be confused with anything affiliated with the Kabbalah Center), it is taught that before the creation of the universe, all of everything was perfectly and seamlessly unified and undifferentiated, and existing in a single point of pure unconsciousness, which was G-d.

Somehow, in an unprecedented flicker of awareness, G-d became aware of His own existence. This triggered a chain reaction that caused other emanations to sprout into existence as G-d's self-knowledge transformed from infinitely unified to infinitely complex levels of discernment. As energy filtered through these emanations, it became a copy of a copy of a copy of itself, slowly corrupting the further it scattered from its source, until it crystallized into actual matter, the lowest possible emanation of divine consciousness. This is the world we occupy, Malkuth, or "The Kingdom", an equally beautiful and ironic term of describing the eventual resting place of G-d's original moment of enlightenment.

I've always thought this model of creation was perhaps an incredibly poetic way of describing Big Bang Theory, and how singular moments of imbalance-- or epiphany, if you will-- wind up triggering icomprehensibly complex results on a personal as well as cosmological level. Just thought you might be interested in a different perspective.

By: edd

edd — Thu, 21 Feb 2008 10:28:45 -0800

jamjam: You'll see Baez talks about the FRW universe a lot. This is the solution to general relativity that cosmologists use all the time, because it's the simplest one to fit observations. There's no rotation in it. I don't know much about other solutions, but I believe there's a class Goedel found that include rotation. I'm not sure what observational constraints there are on any rotation in our universe, but I don't think there's any reason to think it does rotate.

By: LionIndex

LionIndex — Thu, 21 Feb 2008 13:55:49 -0800

I'm not sure what observational constraints there are on any rotation in our universe, but I don't think there's any reason to think it does rotate.

This is kind of a dumb question, but, rotation relative to what?

By: flabdablet

flabdablet — Thu, 21 Feb 2008 23:52:40 -0800

Rotation is actually absolute.

You can figure out whether the body of reference you're looking at is rotating because rotation generates a characteristic gravitational field: direction normal to and directed away from the axis of rotation, magnitude linearly increasing with distance from the axis at a rate depending on the speed of rotation.

If you see that gravitational signature superimposed on another one that looks more like one generated by a mass (inward toward the centre of mass, and decreasing quadratically with distance from that centre) you know you're looking at a rotating mass.