In the search for extraterrestrial life, the focus has long been in two primary areas – looking for evidence of microscopic organisms, either past or present, or radio/optical signals from other civilizations. What about other options? What about physical artifacts from advanced space-faring societies? While this may seem like a real long-shot or even unbelievable to many, it is considered to be a possibility by some scientists according to this news article from Penn State University. Perhaps unmanned probes, much like the ones we ourselves have already sent out to a growing number of planets and moons, and even outside of our solar system altogether. But could we find them if they existed?
So far, no obvious evidence for anything like this has been found, although there are oddities such as the “monolith” on Mars’ moon Phobos, an unusual-looking tall bump or protuberance on the surface seen by the Mars Global Surveyor orbiter, but not in enough detail yet to see what it actually is. Many other oddities have been reported on the Moon, Mars and other moons in the solar system over the years. Of course, many are illusions or examples of pareidolia, while others may be worthy of closer study. That is an entire subject in itself.
According to Jacob Haqq-Misra, of the Rock Ethics Institute, and Ravi Kumar Kopparapu, of the Earth and Environmental Systems Institute, “The vastness of space, combined with our limited searches to date, implies that any remote unpiloted exploratory probes of extraterrestrial origin would likely remain unnoticed.” They are publishing a paper which has been accepted by Acta Astronautica and posted online on ArXiv. They continued however, “Extraterrestrial artifacts may exist in the solar system without our knowledge simply because we have not yet searched sufficiently. Few if any of the attempts would be capable of detecting a 1 to 10 meter (3 to 33 foot) probe.”
They have devised a probabilistic method to try to determine how likely it may be to find such artifacts in our solar system. Their conclusion? It would be difficult at this point to say that there aren’t any. That may seem simplistic, but as they noted, there are many places in the solar system which just haven’t been explored enough yet. “The surface of the Earth is one of the few places in the solar system that has been almost completely examined at a spatial resolution of less than 3 feet,” they said.
They summed it up this way: “Searches to date of the solar system are sufficiently incomplete that we cannot rule out the possibility that nonterrestrial artifacts are present and may even be observing us. The completeness of our search for nonterrestrial objects will inevitably increase as we continue to explore the moon, Mars and other nearby regions of space.”
Such a discovery would be momentous if it happened, but for now we can only speculate and keep our eyes open as we continue exploring.