Planetologists from Germany believe that humanity should focus its efforts to find aliens on a narrow strip of the night sky, in which the inhabitants of star systems can, in theory, see how the Earth passes across the disk of the Sun.
Astrobiologists from the Federal Republic of Germany offer an unusual strategy for finding aliens - they say that we can increase the chances of detecting them if we understand how they could see intelligent life on the Earth's surface from their star system and tried to contact it, says an article published in the journal Astrobiology.
“We cannot predict for sure if aliens are using the same techniques to find life outside their planet as we are. But we can say that they will face the same physical problems that we do, and observing the Earth's passages across the solar disk will be the most obvious way to detect humanity,”said Rene Heller of the Institute for the Study of the Solar System in Göttingen. (Germany).
Heller and his scientific advisor Ralph Pudritz from McMaster University in Hamilton (Canada) propose to look for aliens not by chance, "listening" to the entire space around us, but to point focus on those planets and star systems, the hypothetical inhabitants of which could to detect us and already send us their signals.
Scientists say that today planetary scientists are looking for planets outside the solar system, using mainly two methods - the transit method, which is used by the Kepler telescope, and the radial velocity method, used on a number of ground-based instruments, such as the HARPS spectrographs at observatories in the New World.
The first method is very simple in its essence - astronomers search for planets, observing how the brightness of their star periodically decreases at the moment when the planet closes it from Kepler or other telescopes. This method allows you to quickly find even fairly small planets the size of the Earth, as well as study their properties and look for traces of intelligent life on it, observing how the spectrum of the star changes at the time of the passage of its companion across its disk.
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Guided by this idea, the authors of the article tried to determine which inhabitants of which star systems in the immediate vicinity of the Earth, remote from us at a distance of no more than 3.2 thousand light years, could, in principle, see how our planet passes through the disk of the Sun.
Calculations have shown that there are a lot of such stars - about 10 thousand luminaries, theoretically capable of supporting life in the form in which it exists on the surface of our planet. About one hundred of them belong to the yellow and orange dwarfs, similar to the Sun. While the vast majority of the stars on this list have not been studied, the recently launched GAIA probe should catalog and study them in the next 5 years.
The inhabitants of all these planets, if they exist, should have seen the passage of the Earth across the disk of the Sun, as the calculations of Heller and Pudrits show, quite a long time ago, and understand from the shifts in the spectrum of our star that there is intelligent life on the third planet of this star system. Some of them, like the earthlings, could try to contact the discovered "aliens".
For this reason, the authors of the article propose to draw the attention of the Search Institute for Extraterrestrial Civilizations SETI and the recently opened Breakthrough Listen initiative to a narrow strip in the sky where these stars are located in order to maximize the chances of detecting aliens.