Kaltenegger, author of the forthcoming book, "Alien Earths ... is easy to imagine that on many different worlds, purple may just be the new green." More information: Lígia Fonseca Coelho et ...

There are plenty of organisms here that behave like aliens, already ... even if the first signs of life might not have been ...

Astrobiologists say purple planets might be easier to spot than green ones. If alien life uses retinal, exoplanets could shine with a violet glow—making them prime targets for space telescopes.