Many exoplanets may have observed the Earth

While the search for traces of life on other planets has been monopolized by many researchers, two astronomers have asked themselves the opposite question: What would be the worlds that discovered us?

Is there life on other planets than ours? Anything there? Can we contact them one day? We ask ourselves many questions, and they are subject to no matter what. While the new telescopes allow us to analyze the atmospheres of many locations, two astronomers asked the opposite question: How many possible worlds can or could detect us?

In a study published in the journal June 23, 2021, they counted 1,715 stars that may have observed the Earth in the last 5,000 years. Of these stars, 29 habitable worlds may have picked up radio waves coming from Earth. Assuming that extraterrestrial civilizations have similar astronomical instruments, this will allow us to receive our signals.

If we detect exoplanets, they can observe us in the same way

Thanks to the fact that both scientists were able to identify stars that could have discovered us, just as we have observed using exoplanets. This method involves observing the variations in the light of a star, and according to them, detects a star passing in front of it. In fact, when a spacecraft orbits its star, its path between the Earth and the star causes a decrease in luminosity thanks to telescopes. Thanks to it, scientists can reduce the presence of an exoplanet, but also reduce the size of this planet, which is all the larger because of the intense decrease in light.

If this method can detect many alien planets, the reverse is true: other worlds may have observed us in the same way. Only in this way can the earth be discovered by distant civilizations. Using the database of the ESA (European Space Agency), s[…]

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