Is there a possibility that advanced, unidentified extraterrestrial populations might be living secretly on Earth?

That’s what researchers from Harvard University and Montana Technological University suggest in a recent study.

The study explores the idea that “unidentified anomalous phenomena” (UAP), commonly known as UFOs, could be residing underground, on the moon, or even be present here among humans.

The researchers acknowledge that their hypotheses might be met with skepticism by the scientific community. They emphasize, however, that their theories deserve consideration “in a spirit of epistemic humility and openness.”

They refer to these potential hidden inhabitants as “cryptoterrestrials,” describing the idea as a highly exotic hypothesis likely to face significant skepticism.

The researchers cite UFO sightings near potential underground access points, such as volcanoes, as possible evidence that these cryptoterrestrials might be residing in underground or underwater bases rather than merely being drawn to these locations.

Interest in UFO sightings has surged over the past decade, particularly following last summer’s testimony before Congress by David Grusch, a former Air Force intelligence officer and whistleblower.

Mr. Grusch claimed that the American government has recovered alien spacecraft as part of a longstanding UFO retrieval program. NASA has also shown openness to exploring mysterious high-speed objects reported by military pilots.

Despite multiple Pentagon reports on UFO sightings, no concrete evidence of extraterrestrial life has been found. However, the Harvard researchers propose several speculative theories in their paper.

One possibility is that an advanced human civilization from ancient times still exists and observes us. Another theory suggests that an intelligent species evolved independently from humans in the distant past, possibly from “intelligent dinosaurs,” and now conceals its presence.

Other ideas include the possibility that these unidentified occupants traveled from another planet or time period, or that they possess abilities more magical than technological, akin to “earthbound angels.”