UFO sightings are no more than atmospheric electrical phenomenons that people tend to mistake for space crafts, an Australian astrophysicist believes.
The scientist behind the claim, Dr Stephen Hughes, who made detailed studies of meteor showers over Brisbane, Australia, in 2006, told bbc.co.uk that some UFO sightings could in fact be ball lightning – as their appearance occurred at the same time as "brilliant green objects" rolled over nearby mountains.
Ball lightning is a proposed atmospheric electrical phenomenon that refers to luminous, spherical objects that can vary from pea sized to several metres in diameter.
Hughes said the ball lightning, combined with the human psychology and the desire to see something, could explain UFO sightings.
He said it was not a vigorous theory and that it was a suggestion that may be worth exploring.
Ball lightning is usually associated with thunderstorms, but lasts considerably longer than the split-second flash of a lightning bolt.
His theory appeared in a journal of the Royal Society.