A Conversation for World Lines
flyingtwinkle Posted Nov 3, 2004
so the stars at night we see are probably supernovaed or blackholed because we see light many years later from the distant ones they being many light years away
fact_hunt Posted Nov 21, 2004
Yep, but not all stars become supernovas/blackholes, only stars much larger than our Sun will turn into a blackhole, and Supernovae are not very common (useful for us because if one were to occur in our galaxy all life on earth would perish from the cosmic rays). Eventually however, given enough time everything will collapse into a blackhole, so the final destination of everyone's world lines is in a blackhole. Depressing thought really.
Baryonic Being - save GuideML out of a word-processor: A7720562 Posted Nov 27, 2004
The everything-collapses-in-the-end idea is just one theory. It may not happen in this universe as it depends on the critical mass of everything in existence.
Otherwise, that is precisely right.
Thanks for your interest.
fact_hunt Posted Dec 10, 2004
I'd be interested in any other theories you might have on how the universe could possibly end. As far as my cosmology knowledge goes, there are three possible scenarios for the end of the universe, depending upon the curvature of space-time (in which our world lines propogate). If the universe is closed, everything will end (and possibly be re-born) in a big crunch. This is the most appealing to me, I like thinking of a phoenix type universe. However I fear also the most unlikely, as recent measurements show the universe to be expanding at an accelerating rate. The second scenario is a perfectly flat universe, where the universe is bang on the boundary between being cloased and being open (the next case). In this case, and also the open universe case, the universe continues expanding forever. If this is the case the only thing that could possibly happen in the long run is everything collapsing into a black hole, as far as I can see it. We are already in the snare of the black hole at the centre of the milky way, and all things being equal the earth isn't suddenly going to gain a load of energy and climb out of the potential well created by the galaxy. Even if it did, it would probably (in the vastness of time) chance upon some other black hole and fall into that. The only other possibility I can see is that all matter becomes very spread out, but gravity tends to make everything clump together (hence we have galaxies) so I doubt this is a realistic outcome.
Having said that we know very little about what happens to matter that falls into a black hole. I like the theory that black holes are some kind of gateway into "baby universes" that spring from the parent universe. In this case although all our world lines end up in a black hole, they may end up springing out into a whole new universe. The only downside being, any life that falls onto the black hole will of course be ripped apart by tidal forces before making the journey.
I'd love to hear any more you might have to say on the topic, and if this isn't the kind of discussion you were expecting please tell me and I'll find somewhere else to put forward my views.
Key: Complain about this post