Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Titanscape on 03/03/2012 08:48:51

Title: Could the universe have collapsed in on itself before?
Post by: Titanscape on 03/03/2012 08:48:51
Good day, could there have been and older universe which collapsed in on itself before. So that it had a different nature? Perhpas the energy is more than twelve billion years old?
Title: Re: Could the universe have collapsed in on itself before?
Post by: CliffordK on 03/03/2012 12:13:12
If we believe that all matter/energy in our current universe originated form a single "big bang" event, then it would be impossible to observe anything that came before the big bang.

I don't believe that the idea of periods of expansion, followed by periods of contraction, and a new big bang has been excluded.
Title: Re: Could the universe have collapsed in on itself before?
Post by: CZARCAR on 03/03/2012 18:40:33
Quote from: Titanscape on 03/03/2012 08:48:51
Good day, could there have been and older universe which collapsed in on itself before. So that it had a different nature? Perhpas the energy is more than twelve billion years old?
i like this idea which accomodates quantum mechanix?
Title: Re: Could the universe have collapsed in on itself before?
Post by: Gordian Knot on 04/03/2012 17:06:09
My understanding of how the Universe works is that the contraction theory is mostly out of favor these days. Apparently since the Big Bang the Universe is spreading out faster and faster. If this model is correct, we will never see, nor could there ever have been, a collapse of the Universe.
Title: Re: Could the universe have collapsed in on itself before?
Post by: graham.d on 04/03/2012 17:32:57
To be honest, nobody knows. The re-contraction theory does not fit with recent measurements implying accelerated expansion, but this could easily all change at some point. All the models we have are based on an inadequate understanding of the physics (a fully unified theory) and very difficult measurements with large potential errors. The models are also necessarily simplified to make the maths possible.

I am being a little harsh because cosmology is a fascinating subject and I think great progress has been made in understanding the universe, but, like other areas of modern physics, each step forward has revealed how much more we really don't understand. The most famous is probably the 10^120 error between energy of a quantum vacuum and that required to fuel the observed accelerating expansion.
Title: Re: Could the universe have collapsed in on itself before?
Post by: yor_on on 04/03/2012 18:24:26
Hi Graham :)
Long time no see.
Title: Re: Could the universe have collapsed in on itself before?
Post by: graham.d on 04/03/2012 18:26:34
Hi yor_on. Yea, been busy - but hope to have a bit more time now.