The Guardian view on alien life: dark star, bright prospects | Editorial
Looked at in the right perspective, 39 light years is a trivial distance. In the imagination of science fiction writers it is only a hop and a skip away; even without faster-than-light travel, it is a distance that could conceivably be covered by a robot probe or even a colony ship. So the discovery that there are seven Earth-sized planets hurtling around a red dwarf star named Trappist-1 only 39 light years away, and that three of them may well have water oceans capable of nourishing life similar to that of primitive Earth, is deeply satisfying, as well as exciting.
What took them so long? There are already nearly 4,000 planetary candidates known from earlier surveys of the neighbouring stars. The number of stars in our galaxy alone is ungraspably huge: just the margin of error in one estimate is a figure with 11 zeros after it. If even one in a million had planets around it, that would still leave anything between 20m and 40m planetary systems in our galaxy alone. If none at all holds life, that would be completely astonishing. But if some have developed life, we are left with the question named after the Nobel-winning physicist, Enrico Fermi: where are they? Where are the aliens?
Continue reading...