What comes to mind when someone talks about a UFO? Do you think about the cover of a science fiction novel and the image of mysterious bluish lights beaming down from it? Do you think about a time when you were out late at night and you saw a flash of light, wondered what it was only to realize a moment later that what you saw wasn't a UFO - it was just the lights of a plane that was beginning its descent. Do you think of movies, or little green men, cartoons, or do you just turn away shaking your head?

A lot of people discuss UFOs as flying saucers - it seems to be the best description that they can come up with. Others suggest, rather dismissively, that UFO simply means unidentified flying object and that the light that someone saw flashing in the sky was either a plane, a helicopter or a reflection of light off of a cell phone tower or another metal object.

Reflections of light from a cell phone tower do little to explain away "mysterious materials" found in Roswell, New Mexico in the late 1940s. While the United States military has always stood their ground that these materials were merely fragments of a research balloon, a top secret test that ended badly, others offer another explanation. They assert that the materials were fragments of a UFO, an alien craft that crashed rather than safely landing. They believe that the "flying disc" - as it was called by military personnel - that was recovered could not be something from this world, and so began one of the most talked about UFO encounters in the world.

Many who believe that the UFO in Roswell, New Mexico deserved more attention than it was being given, believe that it wasn't something that could just be dismissed. In part, this is likely to have something to do with other stories surrounding the flying saucer. A farmer talked about having found materials miles away from Roswell, and the story was picked up by newspapers, accompanied by photos of the strange find - strips of rubber, something like aluminum foil, sticks. It's a story that has gained so much attention around the world that it has influenced many people's sense of alien life and alien visitations to earth.

If the Roswell, New Mexico story had never become so widespread, UFO and flying saucer may not be so common in our language, in our experiences and in novels, television programming and films. How common is it for people to see a UFO?

It's hard to say, really, because many people who see an unidentified flying object in the sky are reluctant to report it. Either the person who saw a UFO believes that there is a far more logical explanation or merely thinks that no one would believe them if they were to say anything about it. And yet, there are UFO sightings that are shared and that become the topic of conspiracy theories by those who believe that beings from other planets and galaxies have visited the earth.

One such incident occurred in 1980 in Rendlesham Forest in Suffolk, England. Those who saw the UFO all claimed to have seen flashing lights coming from an unidentified flying object that was descending towards the woods - a UFO that was roughly the size of a car and seemed to float on a beam of light. After reports were made about the object, it was discovered that trees were damaged, radio frequencies became nothing but static and soil samples later showed radioactive activity.

Similarly, in Gulf Breeze, Florida in 1987 tales of a UFO began to circulate when a man saw a strange light coming from his lawn. When he saw the flying saucer, he grabbed a camera and started shooting photos as proof of what he had seen. Of course, in this situation, the story was not just of a UFO sighting, but about repeated experiences and of the man's being beamed up onto the craft.

Though discussions of these UFO sightings continue, and there has been audio recordings and photo documentation, it is still difficult to know whether or not the unidentified flying objects were indeed from space. Many claimed, in regard to the Gulf Breeze, Florida UFO sightings, that the man had manipulated the photographs and fabricated the story.

In each case, both sides - the believers and the skeptics - find evidence to support their claims. Those who believe in UFOs and alien visitations cite facts that they claim cannot otherwise be explained. Those who are skeptical offer their own explanations along with their own supporting evidence. Which side is right? For now, that's up to you to decide.