MIT proposes a space laser beacon to attract aliens

The SETI program for the search for extraterrestrial civilizations has been operating unsuccessfully since the 80s of the last century. The basic principle of its operation is to look for signals or phenomena in space that will differ from the general "background" in the radio or optical range. If we imagine that our brothers in mind are doing the same, then our strategy is wrong - earthlings have not yet bothered to send a clear signal to the Universe about themselves.

Should or shouldn't it be necessary to attract the attention of alien civilizations? Since we started looking for them, it will happen anyway. And it would be advisable to designate yourself in advance, they say, in such and such a sector of space there is intelligent life. For this purpose, a feasibility study was prepared for the construction of a space laser beacon.

The study's author, James Clarke, says the system should be dual. This is a 2-megawatt laser with a reflector 30 m in diameter and a 1-megawatt laser with a 45 m reflector.They will emit signals alternately at different intervals to show the man-made nature of the phenomenon, and such light can be seen even against the background of radiation from the sun on distance up to 20, 000 light years. Further, the scattering will become too strong for transmission of coded information in this way.

Today, there is no technology for creating such powerful lasers, or such huge reflector mirrors, or economically viable energy sources. In addition, the laser beam can inadvertently shoot down satellites that hit it, so it is not very convenient to place a space beacon on Earth. And here the Moon comes to our aid, its reverse side, from where you can safely send signals with a laser of any power. Plus, there are substantial reserves of helium-3 almost underfoot, so the issue of the energy source has also been resolved. Such a grandiose project will require the joint efforts of all mankind, but the potential benefits from it exceed the costs.