Quote:
Originally Posted by redpoint5
I've recently been contemplating a universe which contains multiple big bangs. Could that explain dark matter? Could that explain accelerated expansion of our universe as it's tugged at from the outside by many other big bangs?
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The problem is there's no good theory of what caused the Big Bang in the first place. We know what happened from the early fraction of a second of the Big Bang until now, but nothing in between. So trying to add several big bangs would mean we're still way off.
There is a theory of evolution of universes that states that black holes might be the start of big bangs in other dimentions. That theory has been proposed because our Universe seems "finely tuned". In other words, if our universal constants (like the speed of light, the strong and weak nuclear forces, the electromagnetic force, the mass of subatomic particles, etc) were ever so slightly different even by a fraction of a percent then atomic matter, chemistry, stars, etc. would not be possible and therefore life would not be possible. The theory of evolution of universes tries to figure out how our universe is so perfect for these processes to exist. If each universe is slightly different and can reproduce via black holes, then somewhere at some time a universe is going to pop up just right for life to exist, at least according to the theory, which really has zero evidence to back it up.
Quote:
Originally Posted by freebeard
The Electric Universe theory (disparaged by Anton Petrov) says that Dark Matter is a misinterpretation of red shift data. It's age not distance.
And that it's a steady state Universe.
I get confounded by things like how far away it the microwave background? If the expanding Universe [theory] is that the farthest objects move away from us faster than the speed of light in a vacuum, how can there be a microwave background at all?
I  easily. |
There are theories that try to explain a non-expanding universe. But there is really little evidence for those as well. An expanding universe has a beginning, which means it would need something to have caused it's beginning. Some people don't like that idea so they try to find ways to combat what seems so obvious, the universe is expanding.
The microwave background is the farthest we can see. The farther something is from us the faster it moves away from us until you reach a point that visible light becomes infrared, then microwave, then UHF, then VHF, then HF, then MF, then LF, until it's moving away so fast it can't ever reach us (faster than the speed of light to us).
It's kind of like having an infinitely long conveyor belt. If someone is walking toward us on it but the conveyor belt is moving away faster than that person can walk, then they will never reach us.
Of course the theory of relativity is much more complicates. So is quantum field theory. And yet these two theories don't even agree on everything.