[a_dark_knight (OP)]

Hi, I'm new and have a bunch of questions, this is my first one. Hope you can help!

So there's plenty of evidence of a huge explosion/expansion 13.7 thousand million years ago. But what makes us think it was the beginning of EVERYTHING. Couldn't it have merely been *a* big bang caused by something? Couldn't the Big Bang turn out to be relatively tiny compared to the actual entire universe? How do we know that there is nothing behind the CMBR? And isn't this analogous to our previously supposing that the Earth was the centre of the solar system (and indeed the universe)?

Also, in my opinion, just because we discovered a cataclysmic event, doesn't mean it's the answer to all of our questions about our origins. Science can never answer philosophical questions.

Side question: Isn't it illogical to mention something like a multiverse when that goes against the notion of *the* universe? In a similar fashion to how atoms are made up of smaller things so that their name no longer seems appropriate?

[Don_1]

It is true that some regard the big bang as the start of everything, time included. But I rather tend to agree with what you seem to suggest, that it was not the beginning of everything. Of course, we can never know. It is my belief (for the want of a better word) that the universe is cyclic.

There is the universe and the space between the matter in the universe and beyond the universe is an infinite void. The universe may continue to expand to a point of minimum density, whereupon it will cease to expand. It may then begin to collapse until it reaches a point of maximum density, at which time the big bang will repeat. Perhaps it may be that minimum density causes the big bang, though that is a concept I cannot explain.

As for a multiverse, why not? We do not exist in the only solar system; our solar system does not exist in the only galaxy and our galaxy is not the only one in our universe. So why should our universe be the only one in whole void? If the void is boundless (as I believe it to be), I see no reason why there should not be as many universes in that void as there are stars in our universe. As to the concept of a parallel universe, I rather think not. Don't forget, it is we who gave the name 'universe', perhaps 'omniverse' might have been a better name.

Can anyone prove me wrong? I doubt it, but then again, can anyone prove me right? I doubt that too.

[Don_1]

Don't hold your breath if you are counting on Voyager 1 to show us what lies beyond the known universe, Its taken 35 years to get close to the edge of the solar system. Voyager 1 news

[Pmb]

Hi, I'm new and have a bunch of questions, this is my first one. Hope you can help!

So there's plenty of evidence of a huge explosion/expansion 13.7 thousand million years ago. But what makes us think it was the beginning of EVERYTHING. Couldn't it have merely been *a* big bang caused by something? Couldn't the Big Bang turn out to be relatively tiny compared to the actual entire universe?

Yes. In fact the term "big bang" should not be used to refer to an epoch of time where some sort of that went"bang". And I see no reason why it wasn't caused by something. In fact I believe that most cosmologists do believe that it was indeed caused by someting. See the beginnin, i.e. pages i-16 of Principles of Physical Cosmology, by Peebles

[a_dark_knight (OP)]

Okay thanks. But I thought it was a really common view that the Big Bang was *the* start. And as soon as you ask about the beginning of the universe, people say the Big Bang, as if that's a full explanation, when they should say, well there was that Big Bang which happened, but other than that, we have no idea. In my opinion it's a huge distinction that gets palmed off as if it doesn't really matter.

About the multiverse, I meant that the word "universe" is supposed to be EVERYTHING by definition. So the multiverse is just the universe. Doesn't matter if it has 100 dimensions and/or infinitely many parallel "universes" (whatever that means), it's still the universe. The same as atoms were meant to be the smallest indivisible objects. Why do we keep going on wild goose chases? Maybe there's no smallest, no biggest, no beginning. Then everyone can relax and stop looking for some ultimate theory of everything.

[Pmb]

Okay thanks. But I thought it was a really common view that the Big Bang was *the* start.

That is a misleadning statement. There almost seems to be two sets of literature. One for the professional physicist and one for the layman.

[yor_on]

Well, the big bang is thought to be origin of what we can see anyway. But it can't have a sole 'origin', as coming from some point inside a three dimensional room. As far as I get it the big bang is what makes three dimensions and a arrow of time, so there is no three/four dimensional map on with it comes to be before it. And assuming that you shouldn't be able to play the movie backwards to see our universe 'shrink' to some defined position either. In fact, you need a universe before you can speak about it 'inflating', and maybe a 'inflation' is a expression of something more or less 'coagulating' into the room time we see today, with 'expansion'.