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Valley Public Radio Staff
Thu February 21, 2013
Pretty Picture: Mount Etna Boils Over; NASA Adds Color To Shot From Space
Sicily's Mount Etna has been blowing off steam, and lava, this week. NASA's Earth Observing-1 (EO-1) satellite flew over it on Wednesday and took an image that "combines shortwave infrared, near infrared, and green light in the red, green, and blue channels."
The result: "Fresh lava," NASA says, "is bright red — the hot surface emits enough energy to saturate the instrument's shortwave infrared detectors. ... Snow is blue-green, because it absorbs shortwave infrared light, but reflects near infrared and green light. Clouds made of water droplets (not ice crystals) reflect all three wavelengths of light similarly, and are white. Forests and other vegetation reflect near infrared more strongly than shortwave infrared and green light, and appear green. Dark gray areas are lightly vegetated lava flows, 30 to 350 years old."
We think it's pretty.
(H/T to NPR.org's Wright Bryan.)