Astronomers compared old views of the sky with what we see today and found that at least 100 stars appear to have vanished , or were perhaps covered up. While they've seen no signs of aliens just yet, they say parts of space where multiple stars seem to disappear could be the best places to look for extraterrestrial intelligence (ETI). CNET reports:"Unless a star directly collapses into a black hole, there is no known physical process by which it could physically vanish," explains a new study published in the Astronomical Journal and led by Beatriz Villarroel of Stockholm University and Spain's Instituto de AstrofÃsica de Canarias. "The implications of finding such objects extend from traditional astrophysics fields to the more exotic searches for evidence of technologically advanced civilizations."