Why the search for extraterrestrial life should explore extinct aliens

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May 8, 2017

We keep probing space in search of aliens—but what if they’ve gone extinct?

If SETI is any indication, scientists have been extremely eager to detect biosignatures that could be signs of life beyond Earth. We live in an age where every methane molecule found on another moon or planet seems to go viral on Twitter. Yet there hasn’t been nearly as much interest in the far-out but possible theory that there could have been aliens floating around in our solar system -- and even crawling around on Earth -- before they either took off for other planets or were wiped out by some unexplained phenomenon. And no, Ancient Aliens doesn’t count.

Astronomy professor Jason Wright of Penn State University wants us to see the search for life from what some may consider a far-out point of view. The pursuit of biosignatures may be in the spotlight and all over the internet, but Wright is wondering whether the aliens most of the astronomical community is looking for in potentially habitable star systems, like TRAPPIST-1, have left behind something else. Technosignatures are basically evidence E.T. already phoned home. Think evidence of mining or materials that were artificially produced. Wright is not suggesting that he is convinced extinct or long-departed aliens exist or ever existed, but he does believe a thorough search for signs of extraterrestrial life should include technosignatures.

We could be missing signs of E.T.’s that have long since left our own solar system.

“One of the primary open questions of astrobiology is whether there is extant or extinct life elsewhere in the Solar System,” said Wright in a paper to be published in the International Journal of Astrobiology. Implicit in much of this work is that we are looking for microbial or, at best, unintelligent life, even though technological artifacts might be much easier to find.”

Where they would be easier to find, is the question. The impact of Earth’s erosion and plate tectonics over millions and even billions of years is likely to have erased potential technosignatures, though there could be secrets from space hidden deep in rock that is just as ancient. While Wright doesn’t completely cancel out our home base for exploration, there are more likely places in our solar system to find hypothetical signs of long-lost life. Eerie signs left by intelligent beings may still exist on objects such as moons and asteroids, whose subsurface environments would have had a much higher chance of preserving them in the face of meteor collisions and extreme radiation. Even Mars may have secrets hidden far beneath its barren surface.

“If a prior technological, perhaps spacefaring, species ever arose in the Solar System, it might have produced artifacts or other technosignatures that have survived to present day,” Wright theorized.

Just don’t get this guy involved.

(via Phys.org)