Study identifies planets and star systems on which extraterrestrial life could observe human activity on Earth | News from science and technology
Planets on which extraterrestrial life could observe human activity on Earth have been identified by scientists.
Cornell University astronomers estimate that there are 29 potentially habitable planets in the Earth’s cosmic neighborhood where extraterrestrial life could potentially see and hear human traces.
Using a technique used to search for life on other planets, scientists calculated that 1,715 nearby star systems and hundreds of likely Earth-like planets orbiting these stars had unobstructed views of Earth during human civilization.
“When I look at the sky, it looks a little friendlier because it’s like someone is waving,” said Lisa Kaltenegger, director of the Carl Sagan Institute at Cornell University and lead author of the report.
Experts, including Stephen Hawking, have previously warned against contacting extraterrestrial life as it could harm us.
But Ms. Kaltenegger said if these planets have advanced life, someone out there might conclude that there is life on earth that is based on oxygen in our atmosphere or on the radio waves from human sources that swept over 75 of the next stars on their list to have.
“Hiding isn’t really an option,” she said.
“From the perspective of the exoplanets, we are the extraterrestrials. We wanted to know which stars have the right angle of view to see the earth, because they block the light of the sun and because stars move in our dynamic cosmos, this perspective is gained and lost. “
Astronomers can find potentially habitable planets by watching them cross each other in front of the star they are orbiting.
Ms. Kaltengger and Jacqueline Faherty of the American Museum of Natural History reversed this method and used the European Space Agency’s Gaia space telescope to see what star systems the earth could see as it passed in front of the sun.
They observed 331,312 star systems within 326 light years around the Earth and found that 1,715 could see them at some point in the last 5,000 years, including 313 that are now out of sight
Another 319 will be able to see Earth over the next 5,000 years, including some systems where scientists have discovered Earth-like planets.
The next star on Ms. Kaltenegger’s list is the red dwarf star Wolf 359, which is 7.9 light-years away and has been able to see us since the mid-1970s.
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Alan Boss of the Carnegie Institution for Science, who was not involved in the study, called the research “provocative”.
He said that in addition to observing the motion of the earth in front of the star, space telescopes could also spot us nearby even if the cosmic geometry is wrong.
“So intelligent civilizations that build space telescopes could study us now.”
Mr. Boss added that we shouldn’t expect aliens to show up anytime soon, as it takes so long for news and life to travel between stars and civilizations.