What if — stick with us here — an unknown technological civilization is hiding right here on Earth, sheltering in bases deep underground and possibly even emerging with UFOs or disguised as everyday humans?

In a new paper that's bound to raise eyebrows in the scientific community, a team of researchers from Harvard and Montana Technological University speculates that sightings of "Unidentified Anomalous Phemonemona" (UAP) —  bureaucracy-speak for UFOs, basically — "may reflect activities of intelligent beings concealed in stealth here on Earth (e.g., underground), and/or its near environs (e.g., the Moon), and/or even 'walking among us' (e.g., passing as humans)."

Yes, that's a direct quote from the paper. Needless to say, the researchers admit, this idea of hidden "crypoterrestrials" is a highly exotic hypothesis that's "likely to be regarded skeptically by most scientists." Nonetheless, they argue, the theory "deserves genuine consideration in a spirit of epistemic humility and openness."

Bigfoot may be one example of such a crypoterrestrial.

To read more, click here.