But this UFO curious green light was seen hovering over a 19th century windmill in Norfolk.
The curious green light was spotted by photographer Peter Rye who wanted to take night-time images of Denver mill in Downham Market.
The landmark, which was built in 1835, is lit up at night and so Mr Rye set up his camera on a tripod to take long exposure pictures of the mill.
While he was there he didn’t hear or see anything unusual and it is only when he got home to King’s Lynn that he realised there was something odd about the images he’d taken.
The green light was on some images but not others indicating it was not a smudge on his lens and it appeared to have moved from right to left.
Plane? Helicopter? Gyrocopter? The theories abound in and around the villages close to the windmill, which is 30 miles from an RAF base, about what went on that February night.
Malcolm Robinson, founder of Strange Phenomena Investigations, said he thought the photograph showed a Chinese lantern.
He said: ‘[Chinese lanterns] can be from 2 to 6 feet across and a candle can be lit inside them whereupon the individual then releases them into the sky.
‘Chinese Lanterns have given rise to many a false UFO report here in the UK.
‘What I think has happened here is that the paper which makes up the Chinese Lantern could have been made of green paper and the candle would shine through the green paper turning the image/light to green.
‘When photographed, the cold night air would intensify around the light making it blur for the camera.’
Nick Pope, an expert in UFOs, said: ‘It’s an interesting image.’
The 19th century windmill stopped working in 1941 when its sails were struck by lightning but has since been restored and is the last working windmill in Norfolk.