i understand the big bang theory in principle...the rapid expansion of the universe etc...my question is....is this repeatable?..after a while everything will slow down...start contracting again....does it all get sucked back inward until a critical point is reached and than...bang starts over again? has this been going on for eternity...and we has humans just got the luck of the draw this go round?
2007-11-03 16:23:21 · 6 answers · asked by maizee_713 2 in Science & Mathematics ➔ Astronomy & Space
There are quite a few theories about the end of the universe.
1.) Big crunch - the big bang in reverse, as you describe
2.) Big Bounce - similar to the big crunch, but repeats like you describe.
3.) Big rip - the universe expands to the extent that it literally rips itself appart as the rate of expansion exceeds the rate of force mediation. Galaxies loose their gravitational ties to one another, then stars withing galaxies, then planets to their stars, then atoms to one another and the electromagnetic propegation is exceeded by expansion.... on down in scale until even the smallest particles are ripped apart.
This is an interesting one because it indeed matches the observations that the rate of expansion of the universe is increasing rather than staying constant or decreasing.
4.) Big freeze - Heat death, or entropic death. All systems (the universe is a system) seek their lowest energy states. Heat energy only move from hot to cold - if there is no heat differential, no energy is transfered.
Stars burn out, protons decay, black holes evaporate and all that's left is a faint radiation permeating the universe. This would take trillions of trillions of trillions of trillions of trillions of years... and even then the universe would not be far enough along in this process to notice a difference from today as far as time is concerned... This time is finite, but when you think of eternity, that's what we're talking about.
5.) False vacuum - we live in a gigantic, 'stable' quantum bubble that could collapse at any moment. If it does, we would never know or care - we literally would, as far as physics is concerned, have never been here in the first place.... yep, physics can get that weird but when that weird physics is more accurate than common sense...
2007-11-04 04:58:30 · answer #1 · answered by Justin 5 · 1⤊ 0⤋
you are assuming that the universe will contract, this is actually a huge debate in the physics community right now
the thing is you would think it would, everything we know would tell us it should
the thing is that it appears that everything in the universe is not slowing down but rather is expanding at an increasing rate
the reason for this, as best as most physicists will be able to tell you is 'dark energy' possible somehow related to the 'dark matter' that makes up a huge portion of our universe yet we have not been able to detect to this point.......... although everyone wants the final question, what is destined to happen to everything we are a long long way away from being able to say what will happen for sure
As far as I am aware the debate is currently leaning to that the universe will continue to expand forever and eventually go cold
and because of that one the theory of repeating universes is now being cast into doubt
2007-11-04 00:17:10 · answer #2 · answered by Michael W 5 · 1⤊ 0⤋
There is no evidence for anything whatsoever prior to the Big Bang.
The net energy content of the Universe may be zero, with the positive energy of all the "stuff" being cancelled by negative gravitational potential energy. There may, therefore, be no need to supply the Big Bang with stuff to get it started.
On the other hand, there is no evidence against the idea of many "Big Bangs" that are (mostly) non-interacting. No reason to believe that it would happen only once. In fact, Early Inflation tends to imply the possibility of multiple Big Bangs.
2007-11-03 23:38:18 · answer #3 · answered by cosmo 7 · 0⤊ 1⤋
Your reference to 'eternity' is key to the question. Our 'neighborhood' created by the Big Bang is est'm't'd to be 15B yrs old--- as a fraction, 15B/eternity as time goes, is a drop in the bucket.. Although I think the expansion of 'our' BB will continue without contraction (the initial velocity was near light-speed as it was essentially energy and who knows whether or not we may be coming under the gravitational influence of adjacent BBs), I find it difficult to believe that 'new' matter will not appear out of nothingness, 'in our old neighborhood' to repeat the process in perhaps a trillion (1000 billion years). How this process of 'creation' works, (without getting religious -- God works within the bounds of science) should be, if it isn't, a branch of science. Very interesting, I think, is, if there can be multiple Big Bangs in our Cosmos, and I'm sure there can, how many trillions of cubic miles of space is required to produce the energy/matter to initiate a BB? Going back to 'eternity', space is also boundless, so, one thousand cubic light years to the nth degree (any number you wish) that's a lot of eternity and space for an infinite number of BBs and even BB-collisions.
2007-11-04 00:29:42 · answer #4 · answered by te144 7 · 1⤊ 0⤋
Hi. That is my firm belief, but it is not currently supported by observation.
2007-11-03 23:28:54 · answer #5 · answered by Cirric 7 · 0⤊ 1⤋
cant say it might happen in future ......
2007-11-03 23:49:44 · answer #6 · answered by Adarsh 3 · 0⤊ 1⤋