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The Question
(Submitted January 14, 1998)
I have seen programs and read books about the
Universe. Mainly they speak of it either being constant, never-ending or
ever-expanding with the end of the universe happening when it finally
collapses upon itself. Could the "Big Bang" be a continuous cycle of
collapse and expansion, collapse and expansion....? It goes against
everything in me to believe that one day it could end. I don't know how well
I have
stated my question, but I have always understood that matter is a constant.
That paper can be burned and its composition changed, but the atoms are all
still present only in a different form. I also understand that change is
the only certainty in the universe as we know it, so an end does not seem
possible. Has someone who has a respected opinion in this regard discussed
it or disregarded this idea?
The Answer
I think this is a question that has occurred to many people
contemplating the Big Bang. Historically, cosmologists have fallen
into 2 fairly clear categories: those who are very reluctant to
contemplate a 'one-shot' universe (we might call them recyclers),
and those who are not. Right now there is a preponderance of
evidence that the universe will not collapse, based on measurements
of the rate of expansion and the mass density. I agree with you
that this is somewhat less appealing than recycling. However,
I also am interested in how science often challenges my preconceived
ideas, and so I am personally interested in keeping my mind open
on this subject. Die-hard recyclers will undoubtedly be able to
suggest ways of bringing about collapse. You can read more about
the Big Bang on our site, for example at:
http://imagine.gsfc.nasa.gov/docs/science/mysteries_l1/age.html
I hope this helps,
Tim Kallman
for the Ask a High-Energy Astronomer Team
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