Powerful lasers, already built on Earth, can be used to "illuminate" our planet and establish early contact with highly developed aliens. This is the conclusion reached by scientists from MIT, who published an article in the Astrophysical Journal.
“It will be difficult to establish a connection in this way, but it is possible. Already existing lasers and telescopes can generate signals that can be distinguished from natural flashes of light hundreds of light-years from Earth. In a similar way, we will be able to exchange information with aliens at a rate of several hundred bits per second,”said James Clark of the Massachusetts Institute of Technology in Cambridge (USA).
The main question of the universe
In recent years, the Kepler orbiting telescope, the HARPS instrument and a number of other devices have discovered thousands of exoplanets, several dozen of which are inside the life zone and have approximately the size of the Earth. Signs of the existence of intelligent or unreasonable life on any of them have not yet been detected either with the help of the "eyes" of telescopes, or with the help of the "radio ears" of the SETI Institute, which is trying to find the radio signals of aliens.
Nevertheless, scientists still talk about possible hints of the existence of aliens - in mid-October last year, astronomers discovered unusual fluctuations in the brightness of the star KIC 8462852 in the constellation Cygnus, which cannot be explained by natural processes and which may indicate the presence of a highly developed civilization on its planets.
This year, astronomers from the University of California at Santa Barbara (USA) launched a large-scale project in which they look for aliens not by their radio signals, but by observing artificial flares in the vicinity of potentially inhabited star systems. Similarly, according to the authors of this idea, it is possible to look for traces of "brothers in mind" not only in the Milky Way, but also in dozens of neighboring galaxies.
Clarke and his colleague Kerri Cahoy approached the issue from the opposite side. They checked how much effort must be made by the earthlings themselves in order for our planet to be visible to potential "brothers in mind" who simply watch the night sky and are not engaged in a purposeful search for other intelligent beings.
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"Illumination" of the planet, as the researchers note, can be done in two very different ways - by generating a powerful flash of light, not similar in properties to the radiation of stars, or by sending a relatively weak, but constant laser beam into space.
Method by contradiction
The implementation of the first group of ideas is not yet possible - this requires powerful orbital lasers capable of generating 100 gigawatt pulses. Such emitters, according to scientists, will appear at the disposal of mankind only in about half a century.
On the other hand, more modest, but constantly operating lasers with a power of one megawatt, as the calculations of the authors of the article show, can be seen from a distance of about 20 thousand light years during long-term observations of the night sky using relatively modest surface and orbital telescopes with a mirror the size of only in meter.
These same lasers, as noted by Clarke, can be used to exchange information with nearby inhabited worlds. For example, the combination of a two-megawatt emitter and a large optical telescope such as the E-ELT under construction would send data to Proxima b, a potentially habitable planet in the Alpha Centauri system, at tens of kilobits per second.
To provide communication with KIC 8462852 or the TRAPPIST-1 star system, another potentially inhabited "cradle of life", you will need a telescope with a diameter of 45-50 meters, or the transfer of a laser on board an aircraft. In either case, the data transfer rate will drop to 600 bits per second.
“It would be optimal to build such installations not on the Earth, but on the far side of the Moon. There, in principle, they will not be able to damage satellites or deprive people of sight, into whose eyes the beam of such laser "beacons" can fall. While we ourselves are unlikely to be able to accidentally detect them, however, purposeful “direct” observations of nearby planets can already give results,”concludes Clarke.