For many people worldwide, it’s hard to imagine with the vast numbers of stars in the universe and the vast number of planets orbiting those stars that we are all alone. So far, scientists have discovered more than 4000 planets orbiting distant stars, known as exoplanets. Astronomers from Cornell University recently published a study where they ask the question of out of all those exoplanets we are looking at from Earth, could any of them be looking back?
Astronomer Lisa Kaltenegger says that the team asked who could’ve also spotted us. The researchers wanted to know which of the exoplanets could have determined that Earth has life from their vantage point. The astronomer worked with Joshua Pepper, an associate professor of physics from Lehigh University, to identify more than a thousand stars similar to our sun that could have Earth-like planets orbiting at a distance that can support liquid water.
The researchers were clear that planets of this type have yet to be discovered around the stars. The astronomers say it takes a specific location to be able to see the Earth move in front of the sun. As our planet transits the sun, our star would dim briefly from the distant exoplanet’s point of view.
The dimming during the transit would let the distant planet know a planet orbits the star and is the right distance away to have liquid water. In their study, the astronomers identified the thousand closest stars within 300 light-years that could have spotted us. Anyone searching from these exoplanets would be able to see signs of a biosphere in the atmosphere of our planet.
As far away as these 1000 distant stars are from Earth, we can see some of them in the night sky with the naked eye. It’s interesting to consider how many of the exoplanets could know life is on our planet.