Question:
Although the Sun is a giant ball, it is equivalent to a
bright circlar disk when it is viewed from the Earth. Do you know the
distribution of the brightness on the disk for a given wavelength or
could you tell me
where I find the information? Thanks.
Replies:
Junqiang :
I agree that the sun looks like a disk when viewed from earth, but
I would think that it could be treated as a point source in terms of light
reaching the earth's surface. By "brightness on the disk for a given
wavelength", I assume you mean intensity as a function of wavelength. My
understanding is that the distribution of energy as a function of
wavelength (or frequency) is that of a black-body radiator with a
temperature of 6000 degrees Kelvin. Some further discussion on this can be
found in a book called "The Refrigerator and the Universe: Understanding
the Laws of Energy" by Martin Goldstein.
Good luck,
Jim Rubin
Do a web search using the phrase: "solar spectrum" using the search
engine:
www.google.com . You will find many "hits" with great graphics. The solar
spectrum consists roughly of a black body with thousands of fine absorption
lines due to elements in the cooler upper atmosphere of the Sun.
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