There's this idea I find quite interesting that posits that…

There's this idea I find quite interesting that posits that people (especially in moments of existential fear) encounter "things not from here".
Those things or beings change according to the culture, narratives, ideologies or religions of the people experiencing them.
UFO sightings really took off after the realization spread that humanity thanks to nuclear bombs now has the ability to annihilate itself.
This existential fear called for encounters from beyond (saviors?). Our technological time, of course, produced crafts and extraterrestrials to fulfill this role, instead of nymphs, gnomes, spirits or angels of other times.
The interesting part is that this doesn't mean that such encounters are fake or imaginary.
Real or not, they fulfill a psychological desire of not being alone. A hope of a surprise happy ending.
Either way, they open up the possibility of a "beyond".