Mercury,
Sep/Oct 2001 Table of Contents
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Courtesy
of SOHO/The EIT Consortium/ESA/NASA.
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After
nearly two centuries of debate, recent neutrino experiments have
solidified our understanding of solar energy production.
by
John Bahcall
What
makes the Sun shine? How does the Sun produce the vast amount of
energy necessary to support life on Earth? These questions challenged
scientists for 150 years, beginning in the middle of the 19th century.
Theoretical physicists battled geologists and evolutionary biologists
in a heated controversy over who had the correct answer.
The
questions "How old is the Sun?" and "How does the
Sun shine?" are actually two sides of the same coin. We can
easily compute the rate at which the Sun radiates energy by measuring
the rate at which energy reaches Earths surface and factoring
the distance between the Sun and Earth. The total energy that the
Sun has radiated over its lifetime is approximately the product
of the current rate of energy emission, which is called the solar
luminosity, times the age of the Sun. The greater the radiated energy,
or the older the age of the Sun, the more difficult it is to explain
the Suns source of energy.
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