big crunch

[rangerreich]

Would we still have a theory of the big bang if we were 15 billion years from a big crunch? That is to say given the theory of the big bang and that it may be possible for all matter to collapse in on itself (big crunch) and we or someone like us were here during the this collapse would they have ever came up with the idea that the universe started from the big bang? It would appear to them that all the matter in space was coming from some far off and unknown place and collapsing in on itself.

[Tormod]

Hey, good question. I nver thought about that.

According to the book "The Five Ages os the Universe" this is not likely to happen. However, if and when it happens, it will be so far into the future that all the planets and stars are dead, so there is no life around.

One of my problems with the "big crunch" theory is that while the Universe started out as a singularity, and wnet through a period of incredible inflation and expansion (which we still observe), the opposite may not necessary be possible.

Since the Big Bang created everything that is in the Universe (as we know it), then our Universe has no center. That the Big Crunch would force everything to retract towards some "center of the cosmos" is not likely. Rather, I think it would collapse onto itself, either by evaporation (into what? black holes, maybe? other universes?) or by simlpy phasing itself out, as an inverse of the big bang. But NOT like a balloon which just leaks air and becomes smaller and smaller.

Tormod

[lindagarrette]

I personally like the "big spat" theory that is sort of a continuation of inflation but there is another one out there that seems to be hot, so to speak -- the idea was developed by Neil Turok of Cambridge University, Burt Ovrut of the University of Pennsylvania, and Paul Steinhardt and Justin Khoury of Princeton University.

"The [Ekpyrotic] scenario is that our current universe is [a] four-dimensional membrane embedded in a five-dimensional 'bulk' space, something like a sheet of paper in ordinary three-dimensional space," Turok told SPACE.com. "The idea then is that another membrane collided with ours, releasing energy and heat and leading to the expansion of our universe." Check the web for more.

[}{avok]

What about the implications of a reversal in the direction in time as a possible reaction to the big crunch

[Tim_Lou]

Originally posted by: lindagarrette
I personally like the "big spat" theory that is sort of a continuation of inflation but there is another one out there that seems to be hot, so to speak -- the idea was developed by Neil Turok of Cambridge University, Burt Ovrut of the University of Pennsylvania, and Paul Steinhardt and Justin Khoury of Princeton University.



"The [Ekpyrotic] scenario is that our current universe is [a] four-dimensional membrane embedded in a five-dimensional 'bulk' space, something like a sheet of paper in ordinary three-dimensional space," Turok told SPACE.com. "The idea then is that another membrane collided with ours, releasing energy and heat and leading to the expansion of our universe." Check the web for more.

isnt it the string theory?? string on the 11th dimension is huge and like a membrane....

[Tormod]

Tim - the Ekpyrotic theory is not string theory but an alternative view in cosmology. It has relations to M-theory but as far as I know it does not predict 11 dimensions. It does involve branes, however.

There is a good introduction to this at Princeton:
http://feynman.princeton.edu/~steinh/npr/

Tormod

[Evanescence]

ive got a stupid question - but its intiguing...what exaclty IS 4D and 5D, etc. how can you go further than 3D??? it's hard to imagine lol :S

[Tea Towel]

My understandingof imaginingother dimensions ie 4d. You can get a basic idea of a 4d cube and imagining the net of a 3d cube with a 3d cube on each 2d square. Theoretically this would create a 4d cube or so my Physics teacher has led me to believe. I hope what I said makes sense and helps.

[deamonstar]

Originally posted by: Evanescence
ive got a stupid question - but its intiguing...what exaclty IS 4D and 5D, etc. how can you go further than 3D??? it's hard to imagine lol :S

well... it's rather simple, really. there are three dimensions of space. those being: up/down, left/right and forward/backward. there is also one dimension of time, through which, three dimensional space progresses; giving us four dimensional space-time.

[Uncle Martin]

Originally posted by: Tormod
Since the Big Bang created everything that is in the Universe (as we know it), then our Universe has no center. That the Big Crunch would force everything to retract towards some "center of the cosmos" is not likely.

Do we know there is no center of the universe? The center of the "observable universe" is Earth. The whole of the universe is unknown. I've read theories regarding the shape of our universe as a bubble to a trumpet shape and everything in between. A geographical center may be difficult to speculate, but shouldn't there be a center of gravity? I think regardless of the shape, there must be a center of gravity, in which case, should the big crunch prove true, that will be the geographical center as well.

Another hypothesis I've read speculates that the big bang is a dynamic event rather than an instant in time. It states that time, energy and matter are continuously forming and expanding. This is interesting to me, in that it fits with the current accelerated expansion we observe. If more stuff is forming behind us, it could be pushing us out of the way. Just some late Saturday night, off the wall rantings.