Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Fabs on 06/02/2011 20:30:02

Title: Can we find the centre of the Universe?
Post by: Fabs on 06/02/2011 20:30:02

Fabs  asked the Naked Scientists:
   
Can we determine where the centre of the universe is and possibly the location of the big bang?

What do you think?

Title: Can we find the centre of the Universe?
Post by: Bill S on 06/02/2011 22:16:36

Hi, Fabs, welcome.

I have a feeling I have posted this, or something very similar, in another thread.  If so I apologise for the repetition.  Anyway, it's just a non-scientist's ramblings.

  Excluding the possibility of a pre-existing “somewhere” we can say that it makes no sense to talk of the Big Bang as having happened at a particular place.  Never-the-less, it is difficult for the non-scientist, like myself, readily to shake off the idea that there must be some place in the Universe where it all started. 
The usual response to this in popular science books is simply to state that the Big Bang “happened everywhere”.  Perhaps this is an area in which the balloon analogy can help.  Imagine an un-inflated balloon on which you mark a small dot.  As you inflate the balloon, the dot grows.  Now, ask yourself where, within that enlarged patch, you might find your original mark.  Obviously, the answer must be “everywhere”.  The same can be said of the Big Bang.  At the instant of “creation” it encompassed the entire Universe, and as the Universe has expanded it has not left behind some original Big Bang site.  Having said, and perhaps accepted, all this; if we return to the balloon analogy, there must always be a feeling that because the mark expanded evenly in every direction from the centre, that must be its spreading centre.  I suspect that it is this feeling, rather than an inability to accept that the Big Bang happened everywhere, that is the lay-person’s chief difficulty.  Obviously your original dot has expanded , but has it spread across the balloon?  The answer has to be “no”, because the material of the balloon has expanded, carrying your mark with it.  It is tempting to think that your spot was made in the centre of the extended mark, but such is not strictly the case.