Plants on Other Planets May Not Be Green

Fascinating to think about this one. We're so attuned to the green-ness of plants, it's hard to imagine them otherwise (unless you grew up watching under the sea cartoons).

clipped from space.newscientist.com The greenery on other planets may not be green. Astrobiologists say plants on Earth-sized planets orbiting stars somewhat brighter than the Sun may look yellow or orange, while those on planets orbiting stars much fainter than the Sun might look black. Vegetation colour matters to astrobiologists because they want to know what to look for as a sign of life on planets outside the solar system. Terrestrial photosynthesis depends mostly on red light, the most abundant wavelength reaching the Earth's surface, and blue light, the most energetic. Plants also absorb green light, but not as strongly, so leaves look green to the eye. Extraterrestrial plants will look different because they have evolved their own pigments based on the colours of light reaching their surfaces, says Nancy Kiang of the NASA Goddard Institute for Space Sciences in New York, US.