Back in 1961, astronomer Frank Drake put chalk to board and devised a formula to estimate the number of communicative civilizations in the Milky Way. Just how many alien societies exist and are detectable?
And there's also the paradoxical query asked a decade earlier by physicist Enrico Fermi. It seems like ET should be out there, given the vast amount of cosmic real estate. So, where is everybody?
Over the decades, researchers have been trying to come up with answers to these questions. The search for extraterrestrial intelligence (SETI) is a mix of technology, super-smart software and patience, along with creative thinking. For example, maybe the problem isn't us or our methods.
