Over the millenniums, humans have made various guesses to try and account for unexplained aerial phenomena. Ancient Roman historian Livy speculated they were phantom ships. Some First Century Jews interpreted them as armed angels riding chariots. In Shakespeare’s day, they were assumed to be fairies, incubus, or witches taking flight on brooms.

Consistent with an evolving hypotheses, the prevailing suspicion over the last three-quarters of a century is that unidentified flying objects are of alien origin. More terrestrial conjectures have included top-secret projects, adversarial aircraft, or developmental civilian products. Objects mistaken for alien transport vehicles have included weather balloons, flares, sky lanterns, sun reflection, artificial light distortion, planets, meteors, satellites, swamp gas, and ball lightning.

While the great majority of strange sightings are explicable as being one of the previously-listed phenomenon, a tiny percentage remain a mystery. The problem arises when UFO enthusiasts plug their default ET explanation into any gap that does not fit these categories. These are unidentified objects, which means we don’t know what they are. Penciling in the alien answer is to commit a secular version of the god of the gaps fallacy. For while there have been countless reports of alien visitors and the crafts which transport them, none of these accounts have included a verified living creature, nor have we been able to examine their means of conveyance. No known extraterrestrials live among us, nor are any flying saucers housed in the Smithsonian. Believers have yet to produce a confirmed alien artifact, souvenir, implant, or DNA sample.

That is among the reasons that defaulting to extraterrestrials is a mistake. Metabunk founder Mick West serves as the skeptic community’s foremost UFO expert, each week scouring photos and videos of putative alien craft and offering conjecture based on math and science. His level-headed, in-depth analysis makes West a pariah among UFO enthusiasts. These detractors bypass reason and observation in order to launch ad hominem attacks, such as, “This threatens your world view,” “Your mind is so closed you can’t see what is obvious,” and, “You are going to look like such an idiot when aliens choose to make contact with us.”

If such contact is ever made, it is unlikely to be done by an amateur enthusiast or serendipitous video-camera operator. Conspicuously absent among UFO sightings are any made by those whose job it is to keep track of the goings-on in the sky: Astronomers and military radar operators. Almost all of putative encounters with UFOS are reported by those without training in astronomy, atmospherics, aeronautics, physics, or optometry.

On a related note, if alien life is ever confirmed, it is unlikely to be in the form of a flying saucer landing and requesting an audience with our leader. Astrophysicist Katie Mack explained that the discovery would more likely be made by those in her field watching exoplanets orbit their stars. She wrote, “If we can directly image an exoplanet, or see it pass in front of its star, we can search the spectrum of its light for signatures of chemical balances that only biological organisms can produce.” Another possibility is detecting an electromagnetic signal from life elsewhere or encountering an alien civilization’s equivalent of Voyager. So if we reach each other, it will probably be this type of first contact.

And that may be the only type ever made. A species leaving from the nearest exoplanet and averaging 250,000 miles per hour – fast enough to reach the moon in an hour – would take 11,400 years go get here. This hypothetical journey also assumes managing the logistics of repair, refueling, medicine, and food, all while avoiding the perils of deep space. So aliens would need to travel at amazing speeds while keeping a sustainable population housed, fed, clothed, medicated, entertained, cooperative, and sustained, probably for millenniums.

Sure, they could have managed near-warp travel, may have found a way to utilize wormholes, or have perhaps achieved immortality. But those are all baseless conjectures supported by zero evidence and it requires the most desperate desire to believe to take one of those unproven notions, tie it to flashes in Earth’s sky, and deduce they are coming from interplanetary travelers.