Well it would depend whether you thought the model with lots of observational evidence to back it up or the model with little observational evidence to back it up(and indeed lots of observational evidence agansit it as the two models are obviously mutually exclusive) was correct. Big bang theory produces models that are both infite and finite (in space) and which is correct can only be decided by verifying the difefrent predictions they make.Originally posted by jimmy p
Wouldnt that depend on which theory you prefer to believe? I thought that a lot of people who trust the big bang theory would say that the universe has to be of finite size, and is expanding. im prob wrong, im just some punk A2 student lol.
Frankly my brain hurts when trying to comprehend universal physics. I prefer to believe that the universe is finite size but we dont know what is outside of it. But then again if the universe is everything, how can there be an outside so it must be infinite. But if the universe is expanding, what is it filling? ARGH!!! brain overload!!!
The unievrse is genrally beleived by cosmolgists to be spatially infinite and I'm with them on this one as given the results from WMAP it's difficult to say otherwise (dodecahedrons and toruses excepted).
All of that same evidence is also consistent with a finite universe. With the exception of a very small finite universe, this is not something that can be tested and so is more of a philosophical question.
The big bang thoery is still consistent with the observational data, and that's perhaps the strongest thing you can say about a theory. Of course, there are a number of free parameters, but once you plug those in (as derived from observation) all is well. The big bang theory is NOT a "theory of everything", as physicists like to describe a consistent theory which accounts for all four fundamental forces (gravitation, strong, weak, electromagnetism).
No so, a universe wih a flatness of ~1 is almost certainly infite the other solutions are non-trivial. Also an accelrating universe in standard cosmological models is infinite.
The big bang model or it's current correction; inflation is the standard and it can generate spatially infite universes.
That doesn't matter. A flat universe and finite universe that is multiply connected is still consistent with the evidence, regardless of any human preference for a simpler shape. As well, it is also possible that the universe is spherical but appears flat on small scales, if large enough as a whole.
The acceleration has nothing to do with the size of the universe. A finite universe with a cosmological constant can still expand forever.
You can say it as many times as you want, but a finite universe is still consistent with the evidence.
Slap a cosmological constant with a high enough value and even a closed universe will expand forever - I think.
I don't think they do. Space (not talking about spacetime) can be curved even in the absence of matter. Of course a universe with a hole in its shape seems less natural than a sphere or infinite plane, but that is just an arbitrary human judgment.
Are you sure that wouldn't depend on the intital conditions? If we assume the universe begins with zero volume, I think any size of the current universe is a problem for the standard hot big bang model.
It starts out infinite. If you run the clock back to the early universe, the density gets much higher. In the classic singularity this density becomes infinite, but is so at each point throughout an infinite volume of space. A finite universe gets smaller as the density increases.
expansion is uniform it is the arrangement of matter that gives it it's shape.
Yes, it will expand for ever but not at an accelrated rate AFAIK
No, an infite unievrse has always been infite, but it begins at the big bang, before this time we can't say much. No your thinking 2-D/3-D it wouln't have boundaries.