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Next > Earthshine on the Moon The amount of sunlight that is
reflected back into space due to clouds, bodies of water, snow cover, etc.,
is known as albedo (cloud cover is by far the most influential). Albedo is a major
factor in determining the global temperature. Measuring albedo has proven difficult
in the past, because the calculations were based on knowledge of the total energy
provided by the sun, then subtracting out the energy accounted for by the Earth's
temperature. Basically, it's the difference between how hot the Earth would be if
it absorbed all of the sun's energy. A novel new method of measuring albedo has
been devised that looks at the amount of earthshine illuminating the night side
of the crescent moon. It is much more accurate, and does not depend on calculations
involving the Earth's temperature. After 270 days of measurement, a research team
found that the earth is roughly 10% more reflective than the average during April
and May. This means the Earth is significantly cloudier during those months. NASA's
best computer models predicted only a 5% increase.
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