In this Ancient Aliens, alleged alien encounters and UFO sightings may be of beings from Earth’s future traveling in time machines, and that these same beings could have posed as ancient aliens in the distant past. Is it possible that sightings of alien beings or UFOs may actually be evidence of time travelers from the future? And might ancient astronauts actually be time travelers from our future? Scientists explore the theoretical possibility of time travel. How can it be achieved? And what might people from 10,000 years in the future look like?