Poll: U.S. Hiding Knowledge Of Aliens

(CNN) -- Nearly 50 years since an alleged UFO was sighted at Roswell, New Mexico, a new CNN/Time poll released Sunday shows that 80 percent of Americans think the government is hiding knowledge of the existence of extraterrestrial life forms.

While nearly three-quarters of the 1,024 adults questioned for the poll said they had never seen or known anyone who saw a UFO, 54 percent believe intelligent life exists outside Earth.

Sixty-four percent of the respondents said that aliens have contacted humans, half said they've abducted humans, and 37 percent said they have contacted the U.S. government. The poll has a margin of error of plus or minus 3 percentage points.

But only 9 percent said they believed there were any aliens near the Hale-Bopp comet, which recently passed close enough to Earth to be seen with the naked eye.

Some "ufologists" believed a spacecraft was hidden near the comet, and members of the Heaven's Gate cult committed suicide, believing that they would be taken aboard the craft and returned "home."

What happened in Roswell?

As for the Roswell incident, nearly two-thirds of the respondents to the poll said they believed that a UFO crash-landed in a field outside the New Mexico town 50 years ago next month.

In one of the most famous UFO "sightings" in U.S. history, Roswell residents in 1947 saw lights in the night sky, followed by a loud explosion. A rancher found the "crash site" and removed a large piece of debris, storing it in his shed.

A few days later, Air Force officials from nearby Roswell Air Force Base inspected the site and the debris, and issued a press release announcing the recovery of a "flying disc." The Air Force quickly retracted that statement, and claimed the debris was from a weather balloon.

But countless statements -- some from military personnel -- appeared to contradict the Air Force's revised position. And several "witnesses" claimed to have seen bodies of dead aliens whisked away by the military.

Roswell today capitalizes on its fame as a UFO crash site -- whether or not it actually happened -- and is hosting a 50th anniversary celebration the first week of July.

Friend or foe?

Most people -- 91 percent -- told the pollsters that they had never had contact with aliens or known anyone who had. A similar number -- 93 percent -- said they had never been abducted or known anyone whisked away by beings from another planet.

But if they do meet someone from a galaxy far, far away, 44 percent said they expect to be treated as friends, while 26 percent think they'll be treated as enemies.

Thirty-nine percent don't expect aliens to appear very humanoid, although 35 percent said they probably look "somewhat" human.