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| Jim Lee asks: | |
Does Jupiter radiate its own light? |
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Dr. Bruce Weaver, Director of MIRA, responds: |
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visible light by which we see Jupiter is reflected sunlight minus some wavelengths that
have been absorbed by methane, ammonia, and other simple molecules. [See the article on Maren Christensen’s science project in the Summer
1999 Newsletter – Ed.] Because of heating due to gravitational contraction, Jupiter
emits more infrared radiation than it absorbs. This is significantly more than the
infrared radiation due to its current temperature (any body at a temperature above
absolute zero radiates according to the blackbody law).
The infrared radiation is invisible to the eye. The two sources of infrared radiation also contribute miniscule amounts of visible radiation but this is insignificant compared to the level of reflected sunlight. Hence for all practical purposes, Jupiter does not radiate its own visible light. |
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 Go back to Fall 1999 Newsletter index | MIRA home Contact
mira@mira.org |
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