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More than 4,500 exoplanets have been discovered so far, with only a small fraction believed to have the properties to contain life. A new study suggests that some of those planets and any extraterrestrial life living on them can see us too.
The research, published in the Royal Astronomical Society’s Monthly Notice scientific journal, identified 1,004 Sun-like stars that may have Earth-like planets in their orbit. These star systems have a “direct line of sight for observing Earth’s biological qualities from far, far away,” according to a statement accompanying the research.
“Let’s reverse the point of view on that of other stars and ask ourselves from what point of view other observers might find the Earth as a transiting planet,” said Lisa Kaltenegger, associate professor of astronomy and director of the Carl Sagan Institute at Cornell University. .
“If observers were out there looking, they would be able to see signs of a biosphere in the atmosphere of our pale blue dot,” Kaltenegger added.
Sagan, one of the most famous astronomers in the world, was instrumental in the “Pale Blue Dot” photo taken by NASA’s Voyager 1 spacecraft in February 1990, looking at Earth from over 3.7 billion miles away.
The results, while inspiring, are limited by the amount of time each of the star systems can observe Earth, the researchers noted. Only 508 of them are able to “guarantee a minimum of 10 [hour] long observation of the transit of the Earth, “wrote the researchers in the study.
Study co-author Joshua Pepper said “only a very small fraction” of exoplanets could line up exactly so those on Earth can see their transit, but all 1,004 identified in the document can see us, potentially “drawing their attention. . “
It is also possible that life on these planets could exist for billions of years, given the properties they are believed to possess, a sign that further study is needed.
These planets have been observed due to transit observations, or when an object crosses in front of a star, obscuring the star, thus allowing astronomers to see it. This kind of observation will be expanded when NASA launches its James Webb Space Telescope in October 2021. If an extraterrestrial civilization had its own advanced equipment, similar to the JWST, it might be able to see us too.
“If we found a planet with a vibrant biosphere, we would be curious to know if anyone is watching us or not,” explained Kaltenegger. “If we are looking for intelligent life in the universe, it may find us and may want to contact us. We have just created the star map of where we should be looking first.”
In June, a separate group of researchers suggested there are 36 “intelligent civilizations” in the Milky Way galaxy, a calculation that experts dubbed “the Copernican astrobiological limit.”
A separate study published in mid-May suggested that not only is “the universe teeming with life”, but that it is “the preferred bet”.
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