One of the open questions of astrobiology is whether there is extant or extinct life elsewhere the Solar System. Astronomer Jason Wright at Penn State says that we are looking for microbial or, at best, unintelligent life, even though technological artifacts might be much easier to find. Searches for alien artifacts in the Solar System typically presumes that the origins such artifacts would be from beyond our Solar System, even though life is known to have existed in the Solar System, on Earth, for eons.

But if a prior technological, perhaps spacefaring, species ever arose in the Solar System, it might have…