“Old transmitters typically radiated a power of one million watts, most of which went off into space,” he said. “Transmitters on TV satellites transmit only 20 watts. And that is all carefully focused on Earth, where it is almost all absorbed in the soils of Earth. So the amount of signal that leaves Earth has gone from one million watts to one watt per channel.
“If all transmissions were delivered that way, and I think it will be before too long, we will become almost impossible to detect aside from other means like detecting the light of our cities at night.”
There is another way, though, which is known as Active SETI – sending signals purposefully towards a star or planet in the hope that they will hear us. Drake was part of the first such endeavor, called the Arecibo message, which involved using the Arecibo radio telescope in 1974 to send a direct message containing information on our planet and humanity to the globular star cluster M13.
We are finding more and more potentially habitable exoplanets beyond Earth. NASA
“This raises a whole new question, which is are intelligent creatures altruistic?” said Drake. “Do they want to help or inform other civilizations in space? That is an altruistic act. If [such behavior] is rare, it’s going to take a lot of listening to find a civilization.”
Don’t give up all hope just yet, though. Thanks largely to Milner, SETI has a new lease on life through Breakthrough Listen, and other organizations like the SETI Institute are still busy searching the sky. Whether we’ll ever actually find a signal, well, that’s hard to say. But there is at least a new clamor to look and find out.
“I’m very happy with the state of SETI,” said Drake. “In the days of little funding, it was a terrible career decision to work in SETI. That has all changed, just in this last year. There is a sense that the support will continue for a very long time.”