From up close, Earth has technosignaturesin the form of city lights. From further out,...

[narrator] From up close, Earth has technosignatures
in the form of city lights. From further out, aliens might notice
the satellites and space stations orbiting our planet. From even further,
they might pick up radio signals or stumble across the Voyager probes that are hurtling
across interstellar space. Sometimes the things we think
are technosignatures turn out to be natural phenomena,
like that pulsar. But since radio signals are still
our most promising leads, scientists do a lot of listening
to the sky. [Tarter] If you've seen the movie Contact, there's Jodie Foster on the hood
of the car with the earphones on. It's a bit ridiculous. Because in fact, the computer back
in the observatory control room is doing the signal processing