Top 10 Space Conspiracy Theories

Roswell/Men in Black/Area 51 Conspiracy
Did the U.S. government hide evidence of a crashed alien spacecraft in Roswell, N.M.? Scott S. Warren/Aurora/Getty Images

No discussion about space conspiracy theories would be complete without mentioning the Roswell incident. In July 1947, rancher Mac Brazel discovered some strange debris in an area northwest of Roswell, N.M. Brazel couldn't identify the debris, and a nearby military base released conflicting information about the material's origin. A few local newspapers picked up the story. While people thought the incident was unusual, several years passed before the first theories about alien activity really took off. At that time, dozens of UFO enthusiasts published stories and books about the Roswell incident. The basic theory was that the debris came from an alien spacecraft and that the United States government confiscated the material for later study.

According to some theories, the government transported the debris to an Air Force base in Roswell. Others say they took it to Area 51, a secret military base in Nevada where the government tested experimental aircraft. There were stories of autopsies performed by government officials on dead aliens. Some people claimed that anyone trying to uncover the government's secrets about aliens would receive a visit from a group of intimidating officials in dark suits: the so-called Men in Black. The U.S. government repeatedly denied having any information about extraterrestrials, but many theorists dismissed the government's responses. Officially, the Air Force says that the debris found in Roswell came from a crashed surveillance balloon that was part of a top-secret project called Project Mogul and that it has no information about alien life forms [source: Air Force News].

Another nail in the theory's coffin came when the United States CIA acknowledged the existence of Area 51 in a document about the U-2 spy plane [source: CNN]. The document didn't suddenly blow the lid off of alien technology. Instead, the paper confirmed what many writers have said about the military base -- it was a testing ground for top-secret military aircraft.