An unidentified flying object (or UFO) is a light or object in the air that has no obvious explanation. Some people believe UFOs are spaceships from other planets. However, investigators discover ordinary explaination for most UFO sightings, largely because most witnesses are generally reliable. Many reported UFOs are actually bright planets, stars or meteors. People have reported aircraft, missiles, satellites, birds, swarms of insect and weather balloons as UFOs. Unusual weather conditions can also create optical illusions that are reported as UFOs.
Investigators can explain all but a small percentage of UFO reports. The remainder may be due to an unknown phenomenon or merely to imitations in human perception, memory and research. Most scientists believe that there is not enough reliable evidence to connect these sightings with life from other planets.
Kwentologist Fact File
Some UFOs are called "flying saucers." This term was coined by the press in 1947 to describe a sighting by Kenneth Arnold, a civilian pilot, who reported unknown object speeding through the air.