Big Bang With No Center Fallacy?

Islam Hassan

Either the Big Bang began in a small, restricted area/volume/domain/node/etc or the universe sprang into existence "everywhere all at once" -whatever that means- as I once read somewhere (to explain why the universe has no center). So which is it? And if it sprang into existence in a homogenous way everywhere at once, why call it a Big Bang? Seems like a throw of the 'Big Switch' rather than a Big Bang in that case...

Ryan_m_b

Space was created at the big bang. It didn't expand into anything but the universe did go through a massive expansion.

Cosmo Novice

To say the Big Bang begain in a small area is a little bit off the mark. There was no "empty" space that the Big Bang happened in. It is thought, taking into consideration homogeneity that the Big Bang occured geometrically in all points of space/time and then inflation and expansion followed. Prior to the Big Bang it is thought there was no space/time, so to assume the BB happened at a "point" in space/time fails to take into account that space/time as we understand it did not yet exist.

To clarify for you - the Big Bang did not begin in a small restricted part of space - current cosmoligcal models and pretty universal isotropy (excluding local variance) can rule this out.

Yes, the Big Bang is counter intuitive terminology and interestingly was coined by Fred Hoyle (a steady state advocate and in disagreement with expansion theory) as a derisory term; to Hoyles dismay the term stuck.

Islam Hassan

Thanks for insight. I guess the spatial projection of the BB is another of those phenomena for which no satisfactory lay explanation really exists. The circles-on-a-balloon analogy especially I always found quite inadequate. Another case of mathematics over eyeballs...

phinds

As Cosmo Novice said, the BB is both counter intuitive (at a deep level). It is a VERY unfortunate choice of designations that has caused untold hours of folks trying to overcome the misunderstandings that arise from the idea of an explosion from a central point.

The circles on a balloon analogy is really a very good one if you understand the limitations that it does have and don't get hung up on them.

Cosmo Novice

I totally agree with this, the analogy is a good one, as long as you take into account dimensional representation and apply a 3d analogue to the 2d surface of the balloon. This can then be extended to the n dimension.

I would definetely look at some of the other anologues as well as collectively they can really develop your understanding on current cosmological thinking.