Searching for Aliens Who may be Looking for Us
A new search for extraterrestrial civilizations sets its sights on worlds that may have already found us.
Since just after the birth of radio astronomy, researchers have scoured the skies, looking for intelligent civilizations on other worlds. Now, a new search is looking to find extraterrestrials who have already discovered life on Earth.
Exoplanets — worlds beyond our solar system — are often discovered as they pass “in front” of their sun as seen from Earth. This process, known as transit photometry, measures the minuscule dips in light recorded from a star as a planet passes between its parent star and the Earth. This technique can not only detect planets, but also allows astronomers to learn more about their atmospheres, and could help us detect life on those worlds.
“If other civilizations have telescopes like ours, they would know that the Solar System has planets from their transits, and even know that Earth has life. That is how we have discovered thousands of other exoplanets, so it kind of makes sense to extrapolate and say that that might be how other intelligent species find planets as well. And if they know we’re here, they might be signaling us,” said Penn State graduate student Sofia Sheikh, who headed the study.
