What did the big bang look like?

[scogyrd]

Somebody just asked me this question and I have no idea what the answer is so I thought I'd ask it here. Does anybody know?

edit: the actual question he asked was - what would we see if we saw the big bang itself ?

[davy999]

My guess is nothing, as light had not begun from newly formed stars?

I may and most probably am wrong but thought I would start off on the replies )

[reddoss]

Sorry, could not resist that one.

[FraserClarke]

blue, then white, then red...

The whole universe starts off very hot (billions of kelvin), then cools and cools and cools. So the average radiation colour gets redder as time goes on. Now the universe looks very very black, because the dominant radiation is at 2.7Kelvin, and emitting mostly in the microwave region (the CMB)

Edit: you wouldn't 'see' any structure for a long time, it would be isotropic -- the classic endless white room

[scogyrd]

blue, then white, then red...

The whole universe starts off very hot (billions of kelvin), then cools and cools and cools. So the average radiation colour gets redder as time goes on. Now the universe looks very very black, because the dominant radiation is at 2.7Kelvin, and emitting mostly in the microwave region (the CMB)

Edit: you wouldn't 'see' any structure for a long time, it would be isotropic -- the classic endless white room

Would we see any structure if we were able to observe it from outside the white room?

Thanks for replying everyone btw.

[Adamski]

After watching Prof. Jim Al Kalili's 2 part "Everything" and "Nothing" it appears that in the very beginning there was no light to see only immense amounts of energy from which matter was formed after a colussal battle between matter and antimatter, there was slightly more matter than antimatter so after some more time the matter started to coalesce and eventually particles formed and snowballed suffiently that they started converting the energy into heat and then light was born there after. I think thats what he said anyway.

[brianb]

I think thats what he said

You can't see gamma rays ... and until the universe has expanded & cooled quite a bit, almost all the radiant energy is gamma & hard X ray. If you were there, you'd be instantly boiled away, without even a concrete wall to leave a shadow on like the victims of the gamma flash caused by the Hiroshima bomb.

[Tim]

You'd think it would have a more evocative name than "The Big Bang" really......

[brianb]

You'd think it would have a more evocative name than "The Big Bang"

Such as?

Actually the King James Bible does a pretty poetic job of the creation ... but it's a rotten piece of physics, even by the standards current 400 years ago.

[Axe]

There is a common assumption that the Big Bang was an explosion that occured in empty space and that the explosion expanded into the empty space. This is wrong.

Space and time were created in the Big Bang. At the beginning of the universe, the space was completely filled with matter. The matter was originally very hot and very dense and then expanded and cooled to eventually produce the stars and galaxies we see in the universe today.

Although space may have been concentrated into a single point at the Big Bang, it is equally possible that space was infinite at the Big Bang. In both scenarios the space was completely filled with matter which began to expand.

There is no centre of the expansion, the universe is simply expanding at all points. Observers in any galaxy see most of the other galaxies in the universe moving away from them.

The only answer to the question "Where did the Big Bang happen?" is that it occured everywhere in the Universe.

The Big Bang and the Expansion of the Universe

(this is all copy paste i wrote non of it )

[FraserClarke]

Would we see any structure if we were able to observe it from outside the white room?

There is no outside...

That's the problem with these silly 'explosion' pictures that you always see on telly. It's completely unphysical, and gives the impression of something exploding into something. As Axe's post above says, that isn't what happens, and gives people the completely wrong mental picture unfortunately

[Zakalwe]

Yep, as space and time were created in the BB, it cannot be visualised by our minds. There was nothing to "see"...by asking the question, the questioner is imagining standing looking at something expanding from nothing. The viewerwould be "inside" the expansion, and given that it was at million of degrees K, and that matter as we know it didn't exist (only subatomic particle percursors forming out of the energy), there could be no observer.

Our minds have evolved to survive in trees and on the open savannah. We can easily comprehend the gap between branches, how fast our prey or predators are moving. When it comes to thinking about the universe then our minds just are not geared for it. hence we think that should be an "outside", an edge to the universe, a creator, "something before the big bang".....

[Earl]

L Krauss did say that if we were to see a Big bang, it would look like a sigularity and shrink out of sight.

Ill just nod and say yes

[themos]

The universe was opaque in the early days anyway. You would only be able to "see" a few nanometers (made up, this) in front of you.

[jinstan]

The universe became transparent after a while, but you will see nothing as you were not there, not even the solar system, milky way...

[Wobbly Bob]

This subject certainly taxes the brain :icon_eek:. I have often thought that one can not get something from nothing, and clearly we and the universe are something so in my tiny mind it must have come from somewhere !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[Wobbly Bob]

Just expanding on my last post, the grenade is a small container packed full of energy, when detonated this energy EXPANDS violently. Now I know this is the wrong analagy of the BB. BUT what I cant get me head around is where did all this matter antimatter originate from ?. I suspect we do not know.

[brianb]

the grenade is a small container packed full of energy, when detonated this energy EXPANDS violently.

That's not true. The chemical energy in the explosive is turned into heat energy, the resulting hot gas is denser than its surroundings so the gas expands due to the pressure gradient. The energy does not "expand", it just turns from concentrated chemical energy into widely dispersed kinetic energy.

where did all this matter antimatter originate from ?. I suspect we do not know.

But we do - energetic photons can decay into a particle/antiparticle pair just as a particle-antiparticle pair which happen to meet will annihilate each other resulting in an energetic photon. The only "mystery" is why antimatter is apparently so rare compared with matter ... photon decay should, by the known laws of physics, result in equal amounts of matter & antimatter.

[themos]

I have often thought that one can not get something from nothing

Then the universe must be some weird form of nothing.

[Earl]

I like how there is so much more nothing than something and this nothing is getting bigger and bigger all the time.

[ollypenrice]

I can recommend The Book of Nothing by John D Barrow...

It goes through this stuff in an amusing but erudite way, as befits the great man.

Scholarship worn lightly, says the blurb. Very true in this case.

Olly

[glowjet]

Isn`t Cosmology wonderful, if only you could get your head round it

[Nibor]

There is a common assumption that the Big Bang was an explosion that occured in empty space and that the explosion expanded into the empty space. This is wrong.

Space and time were created in the Big Bang. At the beginning of the universe, the space was completely filled with matter. The matter was originally very hot and very dense and then expanded and cooled to eventually produce the stars and galaxies we see in the universe today.

Although space may have been concentrated into a single point at the Big Bang, it is equally possible that space was infinite at the Big Bang. In both scenarios the space was completely filled with matter which began to expand.

There is no centre of the expansion, the universe is simply expanding at all points. Observers in any galaxy see most of the other galaxies in the universe moving away from them.

The only answer to the question "Where did the Big Bang happen?" is that it occured everywhere in the Universe.

The Big Bang and the Expansion of the Universe

(this is all copy paste i wrote non of it )

Thank you for the link to this most interesting site!!

Brian Cox alerted me to the common misunderstanding of the "centre of the explosion" way of thinking in the last episode of "Wonders of the Universe" but didn't enlarge on it - after a while I was beginning to think I had misunderstood or had misheard him - until now!!

Once again thanks for the link - now all I need do is try and absorb it all!!

[roboticsound]

But we do - energetic photons can decay into a particle/antiparticle pair just as a particle-antiparticle pair which happen to meet will annihilate each other resulting in an energetic photon. The only "mystery" is why antimatter is apparently so rare compared with matter ... photon decay should, by the known laws of physics, result in equal amounts of matter & antimatter.

I thought this had been explained with the decay of X bosons where matter is slightly preferred over antimatter with a ratio of something like 1 part in a billion.

[vulcan]

Of course, all this assumes that we are only considering 'our' universe but the multiverse or 'many worlds' concept postulated by Hugh Everett suggest that there are many parallel space/time universes where every event is a branch point that produces a new and uniques set of consequences. From 'our' points of view, we cannot see and are totally unaware of what is happening in this infinite number of other universes but it may be possible for some particles to pass from one universe to another. Imagine an anti-matter universe parallel to our own where they are wondering why there is so little matter!

Hugh Everett - Quantum Mechanic - "No job too small"