American researchers are claiming that supposed human encounters with aliens and unidentified flying objects (UFO) may just be dreams based on results of a sleep experiment.

The researchers from the Out-Of-Body Experience Research Center in Los Angeles made the findings after subjecting 20 volunteers to out-of-body experiences when they are half-awake at night and asking them to meet aliens during that dream-like state.

Out of those volunteers, more than half were able to achieve out-of-body experiences with seven or 35 percent dreaming of alien or UFO encounters at their home as instructed, according to lead researcher Michael Raduga.

Raduga has a theory that people claiming to encounter aliens or see UFOs are just dreaming, so he conducted the study to prove it.

"When people experience alien abductions in the night, they usually don't know they are actually in REM sleep and having an out-of-body experience," Raduga told Life's Little Mysteries, according to Space.com.

The volunteers had varying response to the instructions. Raduga said there were some who needed more attempts to separate from their sleeping bodies while others failed to do so out of fear. There were also some who never proceeded to looking for aliens while dreaming also due to fear.

Those who encountered aliens described their dreams to the researchers. One described the aliens as resembling the creatures from the movie "The Thing." The volunteered told Raduga the three aliens that appeared before him scared him so he regained consciousness.