Forget green: Purple may be key to finding planets capable of hosting alien life, study says

To observers from outer space, Earth's vast oceans and verdant landmasses make it appear as a blue world punctuated by green ecosystems.

It's the only habitable world we humans have ever known, so of course it's understandable for us to assume that the conditions that allow us to survive would be the standard for other life-sustaining planets. But it's far more likely for astronomers combing the cosmos for signs of extraterrestrial life to eventually stumble upon a habitable planet that scarcely resembles Earth.

While fields, forests and jungles have made green the color most associated with surface life on Earth, that may not be the case for other planets, according to a new study from researchers at Cornell University's Carl Sagan Institute. In fact, the astrobiologists who authored the report contend that it's not ludicrous to think that another habitable planet could be, say, purple.