Alien Planet-Hunters In Hundreds Of Nearby Star Systems Could Spot Earth

https://www.npr.org/2021/06/23/ [login to see] /alien-planet-hunters-in-hundreds-of-nearby-star-systems-could-spot-earth
Right now, a couple of planets about as massive as Earth are orbiting a dim star that's just a dozen light-years away from us. Those planets could be cozy enough to potentially support life. But if any one is living there — and if these life forms have the same kinds of technology that humans do — they wouldn't be able to detect Earth yet.

This will change in just 29 years, according to a report published Wednesday in the journal Nature. That's because stars are constantly moving, and this particular star, called Teegarden's Star, will soon slip into the right location to be able to watch our sun and notice the slight dimming that occurs when Earth passes in front of it.

"If they have the same technique as we do, and if there is a 'they,' then they wouldn't know yet that we exist," says Lisa Kaltenegger, director of the Carl Sagan Institute at Cornell University in Ithaca, N.Y. "In 29 years, they would be able to see us."

She and Jackie Faherty, a senior scientist at the American Museum of Natural History in New York City, have just used a new catalogue of stars and their movements to determine what solar systems could potentially detect Earth in the past, present and future.