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Seeking clarification on singularity at genesis

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acesuv
#1
Apr28-13, 04:09 PM
P: 55
In Stephen Hawking's book, I read that there was no singularity in the beginning of the universe. However, practically every other source I come across seems to be under the impression that there was indeed a singularity before the big bang. I would really appreciate some clarification.

Thx
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What time is it in the universe?
mfb
#2
Apr28-13, 05:43 PM
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P: 11,921
It is unknown. If you just extrapolate the current evolution in the past, you get some singularity, but this is considered as unphysical by many physicists. Some other theories do not have a singularity, or do not consider the very first "moment" of the evolution of the universe at all.
acesuv
#3
Apr28-13, 06:31 PM
P: 55
Quote Quote by mfb View Post
It is unknown. If you just extrapolate the current evolution in the past, you get some singularity, but this is considered as unphysical by many physicists. Some other theories do not have a singularity, or do not consider the very first "moment" of the evolution of the universe at all.
Thank you very much for your reply. I have some follow-up questions which I will post below, but please do not feel obligated to respond at all if you don't want - these could be answered by anyone.

Is the singularity before the big bang analogous to the singularity beyond the event horizon of a black hole, or are they two different things? I've been under the impression that they're virtually the same thing, both being "infinitely" dense. I'm also under the impression that nothing can really be infinitely dense, and that there is a problem with our understanding and that it yields an infinite mass.
I'm very suspicious that I'm waist deep in misconceptions.

mfb
#4
Apr29-13, 01:04 PM
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P: 11,921
Seeking clarification on singularity at genesis

They share the problem that our current theories of physics cannot describe them properly.
acesuv
#5
Apr30-13, 02:52 PM
P: 55
Quote Quote by mfb View Post
They share the problem that our current theories of physics cannot describe them properly.
Is it appropriate to say that a singularity has infinite mass?
mikeph
#6
Apr30-13, 03:01 PM
P: 1,212
Infinite density does not imply infinite mass.
acesuv
#7
Apr30-13, 09:45 PM
P: 55
Quote Quote by MikeyW View Post
Infinite density does not imply infinite mass.
Uh huh. So you're saying it would be appropriate to say a singularity is infinitely dense? Is this what we actually think is going on in a singularity, or is that just what our theories predict?

Thank you


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