> one of the most exciting forms of science. Not to me, I'm afraid. Suppose we detect CO2, methane and ammonia in the atmosphere of some exoplanet tens of ligh

> one of the most exciting forms of science. Not to me, I'm afraid. Suppose we detect CO2, methane and ammonia in the atmosphere of some exoplanet tens of lightyears away. Hell, suppose we detect definite evidence of life. What difference is that going to make to anything? We couldn't launch a probe that could get there in a lifetime, going at half the speed of light. We certainly couldn't get the probe back again. You'd need a generation ship to get people there. I'm quite sure there's life out there. I'm also fairly sure that very little of the life out there is organised for (or interested in) interstellar travel; and for most destinations, that life would have evolved by the time of arrival, and the space-traveller would be something that can only live in space. A civilisation that can build a rocket has existed on Earth for only a few decades, and might only last a few decades longer. We could certainly send a probe to Proxima Centauri. Our great-grandchildren could record the results, if they'd spent two lifetimes keeping the probe in contact and under control (fairly boring astronomy career: maintain contact with a spaceship that was launched before you were born, and won't arrive before your grandchildren have died).