The BIG BANG

Mycroft H

I'm doing physics at leaving cert leavl and we only glanced over the big bang, and now I can understand why! Its bloody confusing!

Couple of questions for ye with the degrees and postgrads and the mad science people out there:
1. The primeaval atom. Reading up that this atom was the beginning of the universe. What did tis contain? Helium, hydrogen? What caused it to split?

2. The ever expanding universe. Apparently were expanding faster then the speed of light..... And einstein (i think) proposed that its elastic. If so are we like a baloon? Are we going to go bang sometime?

3. Whats outside the universe? More universes? Nothingness?

SLIM19198

landyman wrote: »

I'm doing physics at leaving cert leavl and we only glanced over the big bang, and now I can understand why! Its bloody confusing!

Couple of questions for ye with the degrees and postgrads and the mad science people out there:
1. The primeaval atom. Reading up that this atom was the beginning of the universe. What did tis contain? Helium, hydrogen? What caused it to split?

2. The ever expanding universe. Apparently were expanding faster then the speed of light..... And einstein (i think) proposed that its elastic. If so are we like a baloon? Are we going to go bang sometime?

3. Whats outside the universe? More universes? Nothingness?

Why not just ask, whats the meaning of life? ;-)

Mycroft H

SLIM19198 wrote: »

Why not just ask, whats the meaning of life? ;-)

Na monty python has that one sorted.

landyman

landyman wrote: »

I'm doing physics at leaving cert leavl and we only glanced over the big bang, and now I can understand why! Its bloody confusing!

Couple of questions for ye with the degrees and postgrads and the mad science people out there:
1. The primeaval atom. Reading up that this atom was the beginning of the universe. What did tis contain? Helium, hydrogen? What caused it to split?

No it didn't contain any matter. You're talking about a singularity. A singularity is a mathematical concept, but basically it can be thought of as an infinitely small, infinitely dense point. It didn't contain formed nuclei such as Hydrogen or Helium, you can think of it as just containing pure energy.

. The ever expanding universe. Apparently were expanding faster then the speed of light..... And einstein (i think) proposed that its elastic. If so are we like a baloon? Are we going to go bang sometime?

I don't think that the universe is expanding faster than the speed of light, which would in essence be impossible given the implications of special relativity. I'm not sure that it was Einstein who proposed that either, perhaps it was. But, that's only a theory, there isn't any physical evidence to suggest that will happen (while there is some mathematical evidence, I think). One proposal is that the universe will reach a certain point, then start to contract and return to the singularity from which it came, that's called the big crunch theory. Another is that it will continue in a cycle, as in, once the big crunch happens, it will expand again, and that it has been doing this for eternity. That's called the big bounce theory.

3. Whats outside the universe? More universes? Nothingness?

Unfortunatly, that's a question nobody can answer. Perhaps there are other universes which make up a multiverse. Perhaps there is nothing. This is more a philosophical area, science doesn't deal with this too readily, as of yet.

Hope that helped a bit.

Spear

-JammyDodger- wrote: »

I don't think that the universe is expanding faster than the speed of light, which would in essence be impossible given the implications of special relativity.

It was expanding faster than the speed of light in it's early days.

http://en.wikipedia.org/wiki/Horizon_problem

Spear

Spear wrote: »

It was expanding faster than the speed of light in it's early days.

http://en.wikipedia.org/wiki/Horizon_problem

Yah that's true, but in it's present day state it isn't. And I think the OP is wondering more so about the present day than about the early universe. But, valid point anyway.

Professor_Fink

landyman wrote: »

1. The primeaval atom. Reading up that this atom was the beginning of the universe. What did tis contain? Helium, hydrogen? What caused it to split?

Well, this is pretty misleading. Georges Lemaître proposed what we now call the Big Bang theory, but called it the theory of the primeval atom. Bare in mind that when he coined the term 'primeval atom', virtually nothing was known about the early state of the universe. This paper was published in 1931, so the Schroedinger equation in quantum mechanics was only 5 years old, and nothing was known of quantum field theory or or the high energy physics relevant during the early universe. At the earliest point we can say anything with high confidence, after an initial expansion the universe was filled with a quark-gluon plasma. Stable atoms (mostly Hydrogen and a bit of Helium) formed only about 380,000 years after the big bang.

Heavier atomic are former in the core of stars through nuclear fusion (which powers the stars). The heaviest elements are created when stars explode in supernovae, so took a long time to create, only occuring after the first generation of stars began to die off.

landyman wrote: »

2. The ever expanding universe. Apparently were expanding faster then the speed of light..... And einstein (i think) proposed that its elastic. If so are we like a baloon? Are we going to go bang sometime?

Yes, it turns out that contrary to JammyDodger's comments, space can expand much faster than the speed of light, and that during the early expansion stage of the universe space did indeed expand quicker than the speed of light. Space isn't really elastic in the sense you are implying. It doesn't really pull back, and there is no limit to how much you can stretch it. It's a little more like living on a ripple in a pond. The big bang is the moment the stone hits the pond, and then we live on one of the expanding ripples. Gravity does complicate things, but we are a long way from slowing our expansion (actually it appears to be accelerating).

landyman wrote: »

3. Whats outside the universe? More universes? Nothingness?

There essentially is no outside of the universe to talk about. There is no space or time, since everything connected to the patch of spacetime we live on is considered part of the universe. So, since there is no space, and know time, it doesn't make sense to ask where or when questions that do not refer to spacetime locations within the universe.

That's what I get for pretending to know something about it all!:pac:

Professor_Fink

-JammyDodger- wrote: »

That's what I get for pretending to know something about it all!:pac:

Don't worry, I wasn't trying to get at you. Just thought I should clear up any misunderstanding.

Professor_Fink

Professor_Fink wrote: »

Don't worry, I wasn't trying to get at you. Just thought I should clear up any misunderstanding.

Yah I know you weren't! He has to be given the correct information afterall.

timbrophy

landyman wrote: »

3. Whats outside the universe? More universes? Nothingness?

It might help to think of "outside the Universe" as follows. Suppose you had an atlas open with the world drawn as two discs, as you often see, representing the whole sphere. Imagine your kid brother or sister asking "Who lives here?" as s/he points to a spot 1" to the right of the left disc and 3" to the left of the right disc. You have to explain that there is nothing there.

What is nothing? I can't remember where I read the following but it has always stuck with me: "Nothing is NOT what you see with your eyes closed, it IS what you see with the back of your head".

Svenolsen

landyman wrote: »

Na monty python has that one sorted.

Seeing as most of the Universe is composed of Dark Energy and Dark Matter, which nobody understands, Monty Python's guess is as good as anybody else's.

.

Professor_Fink

Svenolsen wrote: »

Seeing as most of the Universe is composed of Dark Energy and Dark Matter, which nobody understands, Monty Python's guess is as good as anybody else's.

Well, we do know largely how these affect things from observation, so we have a pretty good idea of how space time works, although there are still open questions, particularly at the quantum scale.

Evilsbane

Professor_Fink wrote: »

Yes, it turns out that contrary to JammyDodger's comments, space can expand much faster than the speed of light, and that during the early expansion stage of the universe space did indeed expand quicker than the speed of light. Space isn't really elastic in the sense you are implying. It doesn't really pull back, and there is no limit to how much you can stretch it. It's a little more like living on a ripple in a pond. The big bang is the moment the stone hits the pond, and then we live on one of the expanding ripples. Gravity does complicate things, but we are a long way from slowing our expansion (actually it appears to be accelerating).

So space can expand faster than the speed of light, but just to double check: do the objects in space actually move faster than the speed of light or is the space in between those objects stretching? I remember reading something to that effect.

Podge_irl

Evilsbane wrote: »

So space can expand faster than the speed of light, but just to double check: do the objects in space actually move faster than the speed of light or is the space in between those objects stretching? I remember reading something to that effect.

Space itself is stretching - the usual analogy is points on a balloon. As you blow up the balloon the points move further apart, though they are not in fact moving on the balloon themselves.

Evilsbane

Ah, good, thanks. I had to double-check because oftentimes I'd be reading about some recent discovery that supports a particular theory of how things work, but by the time I use that knowledge in conversation it's become obsolete; replaced by a new and better theory.

But I'm still current on that one! Yay!