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Extraterrestrial Plants

May 2, 2007

Lawns on other worlds might not be green, but black, red, or orange.


Colorful impressions of other planets. I’m Bob Hirshon and this is Science Update.

The grass may be greener on the other side of the fence, but on other planets, it might be red, orange, or even black. This according to Nancy Kiang of NASA’s Goddard Institute for Space Studies. She and her colleagues created a model that predicts plant colors on distant planets, based on available light from nearby stars and the planet’s atmosphere. Predictions range from green, red, and orange plants near warmer stars, to black plants that absorb all visible light from dim stars. Kiang says blue plants are unlikely, since blue light packs the most energy for photosynthesis.

NANCY KIANG (NASA Goddard Institute for Space Studies):
So it’s likely that photosynthetic organisms everywhere will try to absorb blue. And therefore won’t look blue to our eye.

Their goal is to help scientists using powerful space telescopes recognize extraterrestrial plant life when they see it. I’m Bob Hirshon, for AAAS, the science society.