The idea of interstellar radio communication was expressed long ago. In the end, in the universe there are not so many ways to transfer information over long distances. Almost the only opportunity to learn something about the distant cosmos is to receive and analyze the electromagnetic radiation of celestial bodies. So, if a certain civilization has astronomy in general, that is, telescopes.
And surely these tools cover all possible types of radiation, from radio waves to gamma rays. For any serious astronomy, this is simply necessary, given how different the sky looks in different ranges. And from the receiver (telescope) one step to the transmitter.
Why radio waves, not, say, visible light or X-rays? They have a number of advantages. For radio communication is not an obstacle interplanetary dust and atmosphere of almost any composition. Radio waves are best focused, which allows you to choose where to send the signal and where to wait for it. The radio signal is most easily changed if it is necessary to put information into it. Finally, radio emission requires less energy, which is also very important.
The first searches for such signals were made back in the 1960s and have since been repeatedly renewed on an increasingly advanced technical basis. Although no one received a greeting from the brothers by reason, or in any case did not notice, humanity does not lose hope and is ready to try again and again.
“Vesti.Nauka” (nauka.vesti.ru) already talked about the project Breakthrough Listen, founded by Stephen Hawking and Yuri Milner. One of the tools involved in this initiative is the Australian telescope.
The search for alien messages with his help began in 2016. But then it was about “listening” to a few stars in the immediate vicinity of the Earth.
Now the work came out literally to the galactic level. This was facilitated by the modernization of the telescope, carried out with the help of a Russian billionaire.
The radio telescope nowadays simultaneously looks at 13 directions in the sky. This allows him to survey the entire area of the Milky Way, visible from this point on the globe. It covers the galactic latitudes from minus 6.5 to plus 6.5 degrees and longitudes from minus 174 degrees to plus 60 degrees. The total area is 3000 square degrees, which is 15,000 times larger than the full Moon.
Astronomers expect to “hear” a transmitter sent to Earth, equivalent to only 20 Arecibo locators, even if it is not closer to Earth than the center of the Galaxy. True, if aliens radiate radio waves not in a narrow cone, but evenly in all directions, they will need more impressive power at this distance: 1014 watts. But a populated planet may be closer, and who knows what energies are subject to the brothers in the mind?
New high-speed receivers perceive 130 gigabits of information per second. Only in 2018 it is planned to spend 1500 hours of observations and accumulate almost 100 petabytes of data. This is one of the most ambitious projects to search for extraterrestrial civilizations (SETI).
The main task in processing information is to identify signals of artificial origin. Developers use for this purpose their own mathematical algorithm and invite everyone to participate in its improvement.
In addition, it is necessary to reject the interference of terrestrial origin. Among the sources of such signals are satellites, airplanes and so on.
This will help the fact that the telescope now receives radio waves from several directions at once. The fact is that terrestrial and near-Earth radio sources are quite powerful (because they are close). They break through even into those petals of the radiation pattern, which “look” is not at all on them. Therefore, such a signal, unlike a truly cosmic signal, looks outgoing from several directions at once.
“We hope to find evidence that our planet is not the only one among the hundreds of billions in the Galaxy where a reasonable life has arisen,” concludes Danny Price of the University of California at Berkeley.
Of course, astronomers are not going to spend the observational time of the instrument, which has become so perfect, solely on the search for a hypothetical “Ay, earthlings!”. In parallel, in the same data, specialists will look for rapid radio bursts – mysterious outbursts, of which we have talked a lot.
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