Add Yahoo as a preferred source to see more of our stories on Google. For as long as humans have looked up at the night sky, we've wondered who, or what, might be looking back. Journalist Becky ...

Here’s what you’ll learn when you read this story: Technosignatures are theoretical signs of technologically advanced alien civilizations, but so far, none of those civilizations have phoned home.

For as long as humans have looked up at the night sky, we've wondered who, or what, might be looking back. From ancient myths about gods descending from the heavens to 20th-century UFO sightings and ...