Astronomers have found 1,715 stars with stunning views of Earth over the past 5,000 years – Technology News, Firstpost

The Associated PressJune 25, 2021 4:26:03 PM IST

Do you have the impression of being watched? It can come from a lot further than you might think.

Astronomers used a technique used to search for life on other planets and turned it around. So instead of looking to see what was there, they tried to see what places could see us.

There are several of them.

Astronomers have calculated that 1,715 stars in our galactic neighborhood – and hundreds of possibly Earth-like planets encircling those stars – had stunning views of Earth during human civilization, according to a study published in the journal Wednesday. Nature.

“When I look up at the sky, it looks a little friendlier because it’s like someone is waving,” said Lisa Kaltenegger, lead author of the study, director from the Carl Sagan Institute at Cornell University.

Even though some experts, including the late Stephen Hawking, warn against reaching out to aliens because they could harm us, Kaltenegger said it didn’t matter. If these planets have advanced life, someone might conclude that there is life here based on oxygen in our atmosphere, or by radio waves from human sources that have swept over 75 of the nearest stars. from his list.

“Hiding is not really an option,” she said.

One of the ways humans look for potentially habitable planets is by watching them cross in front of the orbiting star, which dims the starlight slightly. Kaltenegger and astrophysicist Jacqueline Faherty at the American Museum of Natural History used the European Space Agency’s Gaia Space Telescope to turn the tide, looking to see which star systems might observe Earth as it passes the sun.

They observed the 331,312 stars within 326 light years of Earth. One light year is equal to 5.9 trillion miles. The angle to see the Earth pass in front of the sun is so small that only 1,715 people have been able to see the Earth at any time during the past 5,000 years, of which 313 can no longer see us because we are out of it. of view.

Another 319 stars will be able to see Earth over the next 5,000 years, including a few star systems where scientists have already spotted Earth-like planets as prime candidates for contact. This brings the total to over 2,000 star systems with a view of Earth.

The closest star on Kaltenegger’s list is the red dwarf star Wolf 359, which is 7.9 light years away. He’s been able to see us since the disco era of the mid-1970s.

Carnegie Institution for Science planetologist Alan Boss, who was not part of the study, called it “provocative.” He said that in addition to seeing the Earth moving in front of the star, nearby space telescopes could spot us even if the cosmic geometry is wrong: “So the intelligent civilizations that build space telescopes could study us in this. moment.”

So why haven’t we heard from them?

It takes a long time for messages and life to travel between the stars, and civilizations might not last long. So between those two, it’s enough to limit the chances of civilizations exchanging “TikTok emails and videos,” Boss said in his own email. “So we shouldn’t expect aliens to show up anytime soon. “

Or, Kaltenneger said, life in the cosmos might just be scarce.

What’s exciting about the study is that it tells scientists “where to point our instruments,” said outside astronomer Seth Shostak of the SETI institute who researches extraterrestrial intelligence. “You might know where to look for the aliens!” “