Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: thedoc on 17/04/2014 06:30:01

Title: Are blackholes terraforming space?
Post by: thedoc on 17/04/2014 06:30:01
Clayton Julian asked the Naked Scientists:
   
If everything is spreading away from each other in space, is it possible that everything can gain greater mass and then collapse on itself and making more big bangs?

Could blackholes be terraforming space to make this possible?
What do you think?
Title: Re: Are blackholes terraforming space?
Post by: evan_au on 17/04/2014 10:38:54
There have been a number of cyclic universe (http://en.wikipedia.org/wiki/Cyclic_model) models, many of them driven by gravity.

The discovery that the expansion of the universe is accelerating suggests that gravity will not be strong enough to hold the universe together, to make it collapse again.
Title: Re: Are blackholes terraforming space?
Post by: yor_on on 17/04/2014 19:44:41
Well, what do you think this universe consist of? First you need to define conservation laws, and in which way they are valid. In a 'container model' conservation laws seems more appropriate than in a model where no limits exist, especially if we assume a 'energy' to this universe. Because if a vacuum has a 'energy' you will need to define what happens with it, as a SpaceTime geometry grow. Does it dilute with a expansion? If it stays the same, where does this balance come from? Locally defined any energy you ever measure comes from a interaction between mass and vacuum. So as you find a redshift you either define that from a container idea, in where we somehow, although define a universe as possibly limitless, yet expect it to become larger. Any idea, describing it this way, seems to me to assume a 'outside' from where it can be defined as expanding.