Any aliens in 1,004 nearby star systems can detect life on Earth

  • Astronomers have identified 1,004 sun-like stars that can be in planets like Earth.
  • Any intelligent aliens on those exoplanets would be able to detect signs of life on Earth.
  • Researchers say that these stars may be major targets in the search for alien life: if we know about aliens and they know about us, there may be a better chance to communicate.
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If there are aliens in our galaxy, they may already know about us.

In a new study, two astronomers have identified 1,004 Sun-like stars, which may all be habitable Earth-like planets in their orbits. Any intelligent aliens on those exoplanets should be able to see the Earth and see the chemical signs of life here.

This is because from the point of view of those planets, the Earth passes through the sun each time, orbiting it – a small, dark place in front of the blazing star.

This presence is called transit; Astronomers on Earth use these small droplets to identify planets passing in front of them in the glow of other stars. In just 11 years, scientists have discovered more than 3,000 planets using this method.

Venus transit Sun transit planet

The 2012 transit of Venus across the Sun was recorded from NASA’s Solar Dynamics Observatory.


By measuring how light changes from a star when a transit planet passes in front of it, scientists can determine the size of the exoplanet and, sometimes, the composition of its atmosphere. So it follows that intelligent aliens can do the same about Earth. If they do, they are signs of life: plants on our planet fill the atmosphere with oxygen, and bacteria produce nitrous oxide, a gas that is unlikely to appear without biological processes.

“If we found a planet with a vibrant biosphere, we would be curious about whether anyone was looking at us as well,” the new study co-author Lisa Kultenegger said in a press release. He and his co-author, Joshua Papers, Associate Professor of Physics at Leh University, published their research on Wednesday in the journal Monthly Notices of the Royal Astronomical Society.

All the stars identified in the study are within 326 light years of Earth. This makes him the prime target in the pursuit of intelligent foreign life. If they can see us and we can see them, then there will be a better chance of communication.

“If we are looking for intelligent life in the universe that we can find and want to get in touch with, we have simply created a star map where we should first look,” Cornell University, which directed Cornell University’s Carl Sagan Institute Does, added.

tess stars first science image

Transiting Exoplanet Survey Satellite (TESS) “First Light” image: snapshot of Large Magellanic Cloud (right) and the bright star R. Doradus (left), August 7, 2018.


Kaltenegger and Pepper selected the stars they analyzed from a catalog that NASA uses to identify targets for its planet-finding telescope, the Transiting Exoplanet Survey Satellite (TESS). TESS has scanned about 75% of the sky and found dozens of new planets as well as thousands of possible planets that astronomers are still working to confirm.

Scientists excluded stars for which we do not have reliable data, so there may be more than 1,004 stars around which they found that aliens could see the Earth. Scientists have only observed planets in Kallantinagar and the paper lists about two stars, but astronomers believe that most stars have planets, and billions of stars in our galaxy have planets that may be habitable.

“Only a very small fraction of exoplanets will have to align randomly with our line of sight so that we can see them.” Pepper said in the release. “But the thousand stars we identified in our paper in the Solar Neighborhood could see our Earth crossing the Sun, calling our attention.”

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