Other Planets: From Speculation To Confirmation
Last week NASA scientists put the space telescope Kepler in a kind of technological coma. The craft, designed to search for Earth-like planets orbiting stars in our cosmic neighborhood (within a few thousand light-years, that is), failed and seems to be unfixable. (Hope remains, though.)
Launched in 2009, Kepler has found a total of 132 potentially habitable planets and scientists have a long list of another 2,740 candidates awaiting more detailed analysis. Terrestrial telescopes will undertake the confirmation, since they now know where to look.
At a cost of $550 million, Kepler changed our view of the Universe and of how we fit in, very much like the homonymous brilliant German astronomer from the seventeenth century, an arduous defendant of a sun-centered cosmos and the first to provide mathematical laws describing planetary orbits.
The idea that stars have planets orbiting around them is very old, dating back at least to fourth-century BCE Greece, where philosophers like Epicurus suggested the existence of other worlds:
Moreover, there is an infinite number of worlds, some like this world, others unlike it. For the atoms being infinite in number, as has just been proved, are borne ever further in their course. For the atoms out of which a world might arise, or by which a world might be formed, have not all been expended on one world or a finite number of worlds, whether like or unlike this one. Hence there will be nothing to hinder an infinity of worlds.