Attention aspiring ufologists: July 2 is World UFO Day.
It's a day to raise awareness of what some think are extraterrestrial visits to our planet. The day roughly corresponds to the date of perhaps the most well-known UFO story.
In July 1947, debris was discovered on a ranch northwest of Roswell, N.M., that some think came from an alien spacecraft. Eye witnesses claimed they saw alien bodies at the crash site.
An initial statement from the Air Force said a "flying saucer" had crashed. Later the service said the debris came from a weather balloon.
Decades later, the Air Force issued a report saying the debris was likely from experimental surveillance balloons. Any "aliens" observed in the desert were in fact "anthropomorphic test dummies" that were in the balloons, according to the 1994 report.
The Air Force also investigated UFOs from 1947 to 1969 under Project Blue Book to determine if any sightings threatened national security. It concluded there was no threat and none of the "unidentified" objects were extraterrestrial vehicles.
But one UFO expert says the government has covered up the truth about Roswell and the existence of extraterrestrial visits in general.
"It's cosmic Watergate," said Stanton Friedman, a nuclear physicist who has studied UFOs for more than 40 years. He added, "We're dealing with the biggest story of the millennium."
Why they believe
Thirty-six percent of Americans say they are certain UFOs exist and have landed on Earth, and 11% say they're confident they have spotted one, according to a 2012 National Geographic Channel survey.
The Mutual UFO Network, which investigates UFO sightings, receives thousands of reports each year. To date in 2014, the organization received more than 4,100 reports of a UFO sighting, according to an e-mail from Roger Marsh, MUFON spokesman.
But there is no scientific evidence that these are in fact alien vehicles, said Joe Nickell, senior research fellow at the Committee of Skeptical Inquiry.
"Do UFOs exist? Yes, of course they do by definition. They are unidentified flying objects," Nickell said. But, he said, "You can't say, 'I can't know what that is and therefore it's an extraterrestrial craft.'"
What often happens is there is a UFO sighting, it's quickly explained away and then hoaxes arise, Nickell said. With Roswell in particular, "You begin to get very aging people who begin to confabulate and misremember and put thing they've heard from the rumor mill into memories."
One explanation for why people latch onto thinking UFOs are real without solid evidence is the innate human need to seek meaning in life, said Stephen Diamond, a psychologist in Los Angeles, who has written about the psychological significance of UFO sightings.
"Part of the belief in UFOs is an attempt to transcend our sense of aloneness in the universe," Diamond said. "If UFOs are indeed real and if indeed they are piloted by sentient beings, then we're no longer alone in the universe, and that's attractive to some people."