Centre Of The Universe

[ck1]

Where is it - where did the big bang actually take place?

[jim360]

Everywhere. There *is* no centre.

[joggerjayne]

https://www.google.co.uk/search?q=amex+stadium&client=safari&hl=en&source=lnms&tbm=isch&sa=X&ei=lhtVUqrZJcqR0AXznYGoCw&ved=0CAkQ_AUoAA&biw=1024&bih=672&dpr=2#facrc=_&imgrc=1KXFdtQ7EvzWFM%3A%3Bsm691RUKvOanVM%3Bhttp%253A%252F%252Fwww.brighton.ac.uk%252Fnews%252F2011%252Fimages%252Famex_stadium_nov2010.jpg%3Bhttp%253A%252F%252Fwww.brighton.ac.uk%252Fnews%252F2011%252F110617football_seminars.php%3B452%3B300

[jno]

everywhere, really

http://math.ucr.edu/home/baez/physics/Relativity/GR/centre.html

[sandyRoe]

My nephew used to think he was and the way his parents fawned on him you'd have thought they did too.

[Old_Geezer]

*I* am the centre of the universe !

[ck1]

jno, thanks for the link, that is a good explanation - I still can't understand it, I get the expansion principle and how everything is expanding away from whatever point you view it from but I'm lost on the 'explosion of space' as opposed to the 'explosion in space'. I think I need to go back to books with pictures!!!

[Old_Geezer]

Explosion of space because prior (if that is the word) there was no space. It is being created at a rapid rate. Thus things seem to be moving apart, when in fact, for the most part, they are getting space created between them.

[Old_Geezer]

Except, of course, there were nothing large enough to spot moving apart at that time.

[jim360]

Imagine space as the surface of a balloon. That often seems to work. Then the "centre" of the expansion is inside the balloon and not on the surface. In which case it's not part of space at all. So the centre is in that sense nowhere, but also everywhere.

[LazyGun]

Jeff Beck had it right all those years ago :)

"You're everywhere and nowhere baby"...

http://www.youtube.com/watch?v=avP-8i_YEO8

[ToraToraTora]

to understand you must throw away your everyday concepts. Words "before" ther is no "before" and phrase like what's it expanding into. the universe is always the whole universe. Black box thinking!

[ck1]

It's forgetting the everyday concepts that really gets me. So scientists know what was happening about 10 to the minus 36 seconds after the big bang, so what was happening say 5 minutes before that point?

[jim360]

No idea. Indeed there may not even be such a thing as 5 minutes before. Time begins, presumably, when the Universe does.

[jno]

time and space were created simultaneously. The Bible says much the same thing, so if you were brought up in a religious tradition you could maybe recall how you thought it worked then.

[jake-the-peg]

ck

There are a couple of big leaps of the imagination you need to take
The first one is in the nature of space and the second is in the nature of time

So nothing much really! :c)

A good question is how we know that it is space that is expanding an not a gigantic lump of matter exploding into existing space

The answer to that goes back to Hubble and his law
Hubble discovered that the further away an object is the faster it is receding from us

That's very different from an explosion - in say a handgrenade exposion you would expect all the energy to be transferred at the explosion and all the shrapnel is flying apart at roughly the same speed.

What is happening in space is that it's expanding - every little bit of it. the further two objects are away the more space is between it and so the larger the effect.

Run that backwards and what you get to is a very small point

One of the problems is in dimensions we are aware of 3 but there may be more - we can't imagine them any more than a goldfish imagines outside of the water - this book would blow your mind :c)

http://books.google.co.uk/books/about/Flatland.html?id=h7AN6hI5Ze0C&redir_esc=y

As for time - well that really doesn't work the way you think it does, it goes faster or slower depending on all sorts of things.

An important way it goes slower is in the presence of large gravitational fields - time goes quicker for satellites and your GPS wouldn't work without adjusting for that.

Now think of this when we say the Universe started x billion years ago what do we mean?

Well if you track that big bang back that's where you get to assuming time tracks the way it does now for you and I at our keyboards.


Now imagine we spin the clocks back while we ride the Universe back

As it gets smaller and denser time slows denser and denser slower and slower and we never get to zero

So in a sense if you're 'inside' the Universe it is infinitely old - it has always been here

Whether the Universe started as a big bang or whether it has always been here depends on where you're sitting!

[jake-the-peg]

The latter observation is contentious - there are an incleasing number of serious scientists speculating that 'before' the big bang may have meaning after all big names like Roger Penrose amoung them.

I think it still is a minority view but a growing minority none the less

[jno]

what are the imploications of that, jake? If there was a before, for what or whom might it have existed?

[Old_Geezer]

The time before time existed :-)
Perhaps that is metatime.

[Zacs-Master]

Alexander Vilenkin believes that there was a before and that there were many big bangs creating many expanding bubbles which ties in with the Multiverse theory.

[jim360]

The main implication is presumably firstly that there is a supporting "hyper-universe" in which ours lives, and by extension over separate universes supported in the same way. I don't think there's anything beyond that worth considering though, as it's unlikely that the Universes would interact, or if they would it wouldn't be testable, or if it was testable then it would be pretty violent. But this is beyond my scope of expertise.