On a single photographic plate from April 12, 1950, nine dots of light appear in a row in the night sky. To an uninformed eye, they appear unremarkable, perhaps nothing more than technical errors. Yet this particular photographic plate was produced as part of a larger project to photograph the night sky from California's Palomar Observatory Sky Survey. When lights appear and then disappear without explanation, they are known as transients, and astronomers seek explanations.
This is especially true as UFO sightings have become both more frequent and more effectively documented. Indeed, a group of scientists is arguing that the nine lights of these plates — which were taken seven years before the Soviet Union launched the first man-made satellite into space — could be evidence of extraterrestrial life. (Emphasis on could: there is nothing definitive that says these are alien craft.)
