According to new research , published in the journal Nature, they have identified 2,034 nearby star systems, in the range of 326 light years , from where Earth could be found simply by watching our planet cross our sun.
Specifically, there are 1,715 star systems that could have seen the Earth since human civilization appeared about 5,000 years ago, and 319 more star systems that will be added in the next 5,000 years. In the catalog of 2,034 star systems there are seven known to host exoplanets .
Ross 128 system: the closest
The study used positions and movements from the European Space Agency’s Gaia eDR3 catalog to determine which stars enter and exit the Earth’s transit zone.
Of the 2,034 star systems that have passed through the Earth Transit Zone during the 10,000-year period examined, 117 objects are within 100 light-years of the Sun and 75 of them have been in the Earth Transit Zone since the stations. commercial radio stations from Earth began broadcasting into space about a century ago.
If exoplanets host intelligent life, they can look at Earth against the sun and see the chemical signatures of life in our atmosphere. As Lisa Kaltenegger , professor of astronomy and director of the Carl Sagan Institute at Cornell University explains:
From the point of view of the exoplanets, we are the aliens. We wanted to know which stars have the proper vantage point to see Earth, as it blocks the sunlight. And as stars move in our dynamic cosmos, this vantage point is won and lost.
The Ross 128 system , with a red dwarf star located in the constellation Virgo, is about 11 light years away and is the second closest system with an Earth-size exoplanet. The Trappist-1 system, 45 light-years from Earth, is home to seven transiting Earth-size planets.