Was our solar system once home to an advanced civilization other than our own — perhaps one that predated humanity by hundreds of millions of years before being wiped out by an asteroid impact or some other cataclysm?
Some researchers believe that it is necessary to look for traces of the ancient presence of highly developed creatures here, within the solar system, including the Earth, Moon and Mars.
There is a possibility that hypothetical intelligent aliens could visit the solar system millions of years before the appearance of the first people.
They, according to some scientists, actively developed here, leaving behind technosignatures that can hide deep under the surface or “swim” in outer space.
In January 2018, astrophysicist John Wright published an interesting study in the International Journal of Astrobiology, devoting it to the question of finding traces of alien species in the solar system.
Wright claims that “brothers in mind” could visit the Earth, the Moon, Mars and even Venus (before it turned into an acid hell).
It is unlikely that Venus, given the extremely inhospitable conditions on its surface, could have preserved traces of the presence of anyone. Likewise, it is unlikely that traces of alien activity could survive on Earth, where tectonic and volcanic activity resurfaces and “formats” the interior of the planet at an incredible rate.
What sorts of traces does Wright have in mind? He’s not saying we might dig up aliens’ fossilized bones. Rather, he’s talking about “technosignatures.”
The term encompasses a range of possible artifacts, including archaeological ruins and old mining operations as well as synthetic chemicals or nuclear isotopes that could have been created only by technological processes.
Wright came to the conclusion that traces of the activity of highly developed aliens should be looked for on the Moon, Mars and, probably, attention should be paid to strange cosmic bodies (within the solar system), which may be fragments of ancient probes.
“If progressive beings have ever visited the solar system and stayed here for a long time, then there is a high probability of finding traces of their past activities. I believe that by focusing on the Moon and Mars, we will definitely find some artifacts,” said Wright.
If any technosignatures were left on Mars, however, Wright believes they might still exist. But given the red planet’s thick dust, he writes that “it is unlikely that artifacts might be obvious from space imagery, or even from the sort of shallow probing performed by the various Martian rovers.”
In other words, just because the orbiters and rovers we’ve sent to Mars haven’t turned up any technosignatures doesn’t mean they’re not there. They might simply be lying deep under the surface.
Other places to look for technosignatures include our moon (again, probably under the surface) and the rocky moons and asteroids of the outer solar system. And as Wright told NBC News MACH in an email, there might even be “large structures free-floating in space” — some sort of space stations left over from this hypothetical civilization.
Other scientists are not as optimistic as John Wright, because mankind, developing archeology, has not yet found alien “beam guns” or “mysterious transmitters” next to dinosaur skeletons.
Astronomy professor Avi Loeb believes that in the distant past, aliens could visit the solar system, but searches for “hypothetical ghosts of antiquity” are not as effective as attempts to identify technosignatures in deep space.