Astrophysicist Asks: “Did A Solar-System-Wide Cataclysm Erase Evidence of a Prior Space-Faring Species?”



One of the primary open questions of astrobiology is whether there is extant or extinct life elsewhere the Solar System. Some scientists such as Penn State astrophysicist Jason Wright, a member of the Center for Exoplanets and Habitable Worlds, have considered the possibility that a technological species could have existed in the Solar System prior to humanity's rise on Earth.

In 2016, Wright authored a paper that discussed possible origins and locations for "technosignatures" of such a civilization while other astronomers have suggested looking for lights on Kuiper Belt Objects that "may serve as a lamppost which signals the existence of extraterrestrial technologies and thus civilizations."

"The most obvious answer is a cataclysm, whether a natural event, such as an extinction-level asteroid impact, or self-inflicted, such as a global climate catastrophe," Wright asserts. "In the case of a prior space-faring species that had settled the Solar System, such an event would only permanently extinguish the species if there were many cataclysms across the Solar System closely spaced in time (a swarm of comets, or interplanetary warfare perhaps), or if the settlements were not completely self-sufficient. Alternatively, an unexpected nearby gamma ray burst or supernova might produce a Solar-System-wide cataclysm."

From a purely scientific standpoint, observes Wright, it's a perfectly reasonable question to ask whether life may have existed elsewhere in the Solar System, or does today. That is, increasingly, one of NASA's raisons d'être. But when Congressman Dana Rohrabacher asks about such a civilization existing thousands of years ago on Mars, and attributes the question to "some people," it's justifiable to hold the question up to scrutiny.

Implicit in much of this work, says Wright, is that we are looking for microbial or, at best, unintelligent life, even though technological artifacts might be much easier to find. 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, meaning Solar System artifact SETI provides a potential path to resolving astrobiology’s question says Wright.

In the case of Venus, the arrival of its global greenhouse and potential resurfacing might have erased all evidence of its existence on the Venusian surface. In the case of Earth, says Wright, erosion and, ultimately, plate tectonics may have erased most such evidence if the species lived Gyr ago.

Remaining indigenous technosignatures might be expected to be extremely old, suggests Wright, limiting the places they might still be found to beneath the surfaces of Mars and the Moon, or in the outer Solar System.

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Prior Indigenous Technological Species

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