Free Astronomy Magazine September-October 2020

SEPTEMBER-OCTOBER 2020 It goes around and around - one has the im- pression that each SETI project is thought to find our analogues. Apparently, we just can- not get into the mind of ET. One of the rea- sons why we might not succeed is to be found in the strategies of many SETI proj- ects, which appear to be losers at the start, as they underestimate the capabilities of the hypothetical technological civilizations they would like to discover. We expect, for exam- ple, that these civilizations are identifiable regardless of their will, and that they send messages blindly through interstellar space. We also expect that those messages are not sent continuously but in- stead occasionally, as sending them would be energetically expensive. You see, we are all of this! Someone will cer- tainly remember the questionable message launched in 1974 by the Arecibo Radio Telescope towards the globular cluster M13, about 25,000 light-years away. A civilization more evolved than ours would have enough knowl- edge of the worlds that surround it to know, with good approximation, if and where other civilizations developed and, based on the evolutionary levels on these worlds, it would know if and how to attempt a con- tact. The reduced number of targets would allow for the optimization of energy con- sumption to sustain a continuous signal and, therefore, maximize the chances of success. Sending a continuous signal should be a pri- ority for ET, because this would also allow a civilization like ours, which is unable to “lis- ten” for long periods to a given target, to T he Milky Way arching through the night sky. Composite panorama cre- ated at the Paranal Observa- tory, Chile. At first glance it doesn't look like it, but the stars of our galaxy are so numerous that, in order to find an- other technologi- cal civilization, it would be neces- sary to aim at hundreds of mil- lions of stars with our instruments. [Bruno Gilli/ESO] Alongside, the Mars 2020 Mis- sion rover, one of the best chances we have for dis- covering traces of extraterrestrial life in the coming years. [NASA/JPL- Caltech]