Aliens?

"The possibility of a purely psychological explanation is illusory, for a large number of observations point to a natural phenomenon, or even a physical one - for instance, those explicable by reflections from 'temperature inversions' in the atmosphere. Despite its contradictory statements, the American Air Force, as well as the Canadian, considers the sightings to be 'real', and have set up special bureaus to collect the reports. The 'disks', however, the objects themselves, do not behave in accordance with physical laws but as though they were weightless, and they show signs of INTELLIGENT GUIDANCE such as would suggest quasi-human pilots. Yet the accelerations are so tremendous that no human being could survive them."
-from Carl Jung, FLYING SAUCERS

Popular Mechanics from May, 2001 has a cover story that'll make you wonder.
"WHEN UFOs LAND
At long last, scientists have their hands on the proof skeptics say doesn't exist--physical evidence of flying saucers.
*****The rich really are different. When Laurence S. Rockefeller--yes, those Rockefellers--wanted to know more about UFOs, he didn't have to satisfy his curiosity at alien-hunters' Web sites or in the Weird Science section of Barnes & Noble. He asked Peter A Sturrock, the former director of the Center for Space Science and Astrophysics at Stanford University, to convene a private meeting of a dozen top scientists at the Pocantico Conference Center, on the grounds of the old Rockefeller family estate 20 miles north of Manhattan. Sturrock's guest list and agenda was noteworthy for its omissions. Bob Lazar, who claimed to have reverse-engineered UFOs at Area 5l, wasn't invited. Neither was alien-buster Philip J. Klass of the Committee for the Scientific Investigation of Claims of the Paranormal. Roswell, the 'face' on Mars and other familiar sightings got little attention. Instead, researchers from Princeton University, Stanford, Massachusetts Institute of Technology, and the Center for Space Research in France focused on cases with more meat on their bones--sightings in which physical evidence was left behind. 'While their findings were not conclusive. I hope (they) will raise the level of the debate.' Rockefeller said afterward.