Should we be seeking out aliens on Earth?

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Sep 2, 2017, 2:06 PM EDT

Earth is probably the last place you’d look for extraterrestrials, especially with all the new exoplanet discoveries and the endless quest to prove there was life on Mars at least once in the past something-billion years, but are we looking too far?

Some scientists are less out-there and more down to Earth—literally—when it comes to finding traces of alien life-forms. Not that these hypothetical aliens are actually crawling around our planet. What these scientists argue is that they may have dropped by before humans even existed and left behind technosignatures such as radios, rockets or other tech that might have been lying deep underground or floating around in space for aeons.

Astrophysicist John Wright has elicited more than a few eyerolls with a controversial argument that was recently published in the International Journal of Astrobiology. He believes that technosignatures from an alien species that landed not just on Earth or the moon, but even Mars before its atmosphere was obliterated or Venus before it became a swirl of toxic clouds could have possibly survived somewhere. While Venusian clouds and volcanoes would have long since corroded and liquefied every shred of evidence, he still believes it is possible something could be buried on Earth, Mars or the moon if it hadn’t long ago become space junk.

“If a prior technological, perhaps spacefaring, species ever arose in the solar system, it might have produced artefacts or other technosignatures that have survived to present day,” he said, “meaning solar system artifact SETI (Search for Extraterrestrial Intelligence) provides a potential path to resolving astrobiology's question.”

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The Sloan Sky Survey. 

Wright doesn’t believe aliens actually lived on Earth, and even if they had, erosion and ever-shifting land masses would have turned any trace of them to dust. Hypothetical alien trash would have had a much better chance of surviving in the subsurface of Mars, away from the solar winds and radiation it constantly gets blasted with and too deep to be smashed by meteorite impacts. The Red Planet also has no plate tectonics to crush any ancient computers or whatever they might have scattered around.

Other scientists are more skeptical, possibly because we haven’t yet found any prehistoric ray guns or radio transmitters next to a T-rex skeleton.Astronomy professor Avi Loeb believes that while “there could have been a visit from another civilization” on Earth, the Search for Extraterrestrial Artifacts is more likely to find technosignatures in space, however unlikely that still is. The most effective way to zoom in on something unusual would be a sky survey. Telescopes trained on the night sky would have their repeat viewings analyzed for any unusual objects in space in the vicinity of our planet.

Whether we’d actually recognize something as alien even if we saw is an entirely different thought to keep both scientists up at night.

(via NBC Mach)