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The Question
(Submitted March 27, 1998)
Is there an area in the universe where cosmologist believe the Big Bang
originated?
Depending on where our galaxy (the Milky Way) is located in relationship to
the origin of the Big Bang, might it not appear that the Universe were
expanding or not?
The Answer
The question you have asked is a good one, and it involves concepts
which are foreign to most of our everyday experiences. You may have
heard something of Einstein's contributions to physics, in particular
his theory of relativity. He introduced many unusual and counter-
intuitive concepts that derived ultimately from simple, almost child-
like thought experiments. One of his contributions was showing that,
in a Universe with no matter and no energy, time itself ceases to
exist. Now, one corollary of this that comes into play as far is the
Big Bang is its location. Some think of the Big Bang as a localized
and very powerful explosion. This is not quite accurate. All things
that exist now or ever existed in the past were also present, although
perhaps in different form, when the Universe was created. Therefore
the Big Bang occurred everywhere all at once. You could not assign
a location to it. The Big Bang was not so much an explosion really
as the start of a great expansion, which continues even now. The
rate of expansion would appear to be roughly the same, aside from
local anisotropies, no matter where in the Universe you are.
J.K. Cannizzo
for Ask a High-Energy Astronomer
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