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Q:
can someone please explain the "entropic doom theory".
- Gary (age 13)
Old Buckenham Hall, Suffolk, England
A:
I guess this is a reference to the Second Law of Thermodynamics,
according to which the entropy of the universe keeps increasing. Things
tend toward thermal equilibrium, in which temperatures are uniform and
energy dispersed among many tiny modes of motion (like those associated
with heat) rather than concentrated in a few large-scale modes (like
all the mechanical motions that you can see). At some point, it looks
like the universe will be too run down to support any life.
That's not really worth worrying about since life on Earth will
undoubtedly be wiped out long before that, as the Sun will expand into
a smallish red giant some billions of years from now.
Mike W.
(published on 10/22/2007)
Follow-Up #1: smallish red giant
Q:
Just as a matter of course "smallish red giant" is a misnomer. A red giant is ~100 times the diameter of our sun. It THEN evolves into a small white dwarf.
- Michael (age 19)
South Africa
A:
You’re right that red giants are big compared to the sun. By ’smallish red giant’ I’m sure we meant compared to typical red giants. We were grading size on the curve.
Mike W.
(published on 07/16/07)
Follow-up on this answer.
