Finding signs of biological activity on other planets will tell us just how common life is in the universe

摘要

Do we have company in the universe? In the next three decades we'll probably know. I'm confident that we'll detect signs of life on exoplanets (planets around other stars) by observing the atmospheres of the planets that we're detecting now-especially those similar to Earth in mass and orbit-and finding oxygen and other chemical signatures there. We may not discover technological civilizations in the next 30 years, but we should be able to find evidence for simple life-forms. To reach that goal, we'll need a space mission that can obtain spectra of exoplanets' atmospheres. This involves blocking out the light from the central star and bringing light from the dim planets into focus.