The TESS space telescope starts a new era of planet hunting, greatly increasing the odds of finding another truly Earth-like planet among the stars. But how will we know if there is a civilization like ours on an alien world?
The Transiting Exoplanet Survey Satellite is a follow-on to the highly successful Kepler space telescope. The Kepler mission discovered more than 2,600 planets orbiting other stars, with thousands more possible detections that have yet to be confirmed. But Kepler only looked at one portion of the sky, a small patch around the constellation Cygnus, about 500 or 600 light-years away. TESS will examine the entire sky over two years and look at stars that are closer to Earth, between 30 and 300 light-years away.
Finding a planet like Earth orbiting another star is not easy because Earth-like planets are small, as planets go. You could fit 1000 Earths inside the planet Jupiter. And to be really Earth-like, a planet must be not too close or too far from its parent star — in the “Goldilocks” or habitable zone where the temperature will allow liquid water to exist on the surface.
And finally, conditions have to be right for organic chemistry to somehow develop into living organisms. Then the possibility exists that those simple organisms could evolve into more complex life forms, and perhaps into intelligent beings who could build telescopes to look out into the cosmos and ask the same question that we are: “Is anyone else out there?”