THEY are a staple of science fiction and have convinced generations of the existence of extra-terrestrial life.
But although for most people flying saucers exist only in films and TV shows, the Ministry of Defence today revealed it has investigated 22 cases of mysterious objects appearing in the skies above the Lothians over the past decade.
The Government has opened its records over UFO sightings for the first time, containing eyewitness reports from across Edinburgh and the surrounding regions.
Aviation experts have been drafted in to investigate reports including "jelly-fish shapes", "big, round swirly things" and fireballs streaking across the Lothian skies.
One woman noticed a series of flashing lights flying over Corstorphine Hill at night in 1998. She said it was in a diamond-like formation and flew low over the hill before heading towards the city. Paranormal investigators said at the time they were puzzled by the lights and urged more witnesses to come forward, but the mystery was never solved.
Other incidents, such as two "fuzzy white lights" that danced over Leith in 2001 and a "swirly" object appearing above East Linton last year, have also never been explained and have been seen by some as evidence of extra-terrestrial activity. However, some reports to the MoD would seem easier for aviation experts to explain, such as an eyewitness description of an object in Barnton Park in 2004 "resembling the front of a helicopter".
Some UFO sightings have also been put down to natural causes, such as a mysterious light seen streaking across the sky above Midlothian at the end of last year.
At first David Carson thought he saw a burning aeroplane dropping from the sky. But when he realised he wasn't witnessing an aviation disaster, he reached for his camera and spent ten minutes photographing what he saw, about a mile south of Penicuik.
Described as "going in all sorts of weird directions", the lights sparked frantic calls from witnesses to the MoD and experts at Edinburgh's Royal Observatory, who were told it was an alien craft. At first, astronomers thought it was a piece of space debris or a meteor burning up in the atmosphere but they were later stumped when an amateur photo of the light failed to match their conclusions.
Although witnesses maintained it was proof of anything from extra-terrestrial activity to a secret test of new military aircraft, experts at the observatory later said the light had been caused by an unusual glare of the sun on a passing plane's condensation trail.
A sighting of an orange ball of fire with a long tail in Broxburn in 2004 was also eventually highlighted as naturally-occurring, with astronomers stating it had been caused by a meteor burning up while entering the Earth's atmosphere.
So far, the sightings have not attracted the same level of scrutiny as some unexplained events in the US, such as the Roswell Incident - where Government officials allegedly found a flying saucer that had crashed in New Mexico.
Nevertheless, UFO enthusiasts and investigators have maintained that many of the Lothian incidents reported to the MoD show there could be extra-terrestrials visiting the Capital's skies.
Paranormal investigator Ron Halliday, chairman of Scottish Earth Mysteries Research, said the data released by the MoD represented "just a fraction" of the reports of UFOs in the Lothians.
He said: "Some of these incidents are difficult to explain, so there's every chance that they could be proof of something that is not of this world.
"I've seen and heard of hundreds of reports of unidentified objects from around the Lothians since the 1990s. It's one of a handful of hotspots across the country where there seems to be a lot of activity happening.
"The MoD used to completely ignore any reports of mysterious objects, which is why only a handful have been published. People don't think to contact them because they either think they won't be taken seriously or the incidents will be covered up.
"But this shows that the Government is starting to take these sightings seriously. They're logging the reports now and must be investigating some of them."
Mr Halliday, who has been a paranormal investigator for more than 20 years, admitted that some of the sightings were probably caused by witnesses "misidentifying" objects in the sky. However, he added that there were some cases where there was no rational explanation for the phenomena.
He said: "People misidentify things all the time, so you can't say that all of these are genuine UFOs. Some could easily be satellites or meteorites entering the atmosphere, or they could be unusually bright planets like Venus, which are tricky to identify correctly at night.
"But there have also been a lot of daytime reports, which are more difficult to explain away. I've spoken to groups of people who have witnessed something unusual during the daylight and have taken pictures of it - and there's been no logical explanation for it.
"A lot of the descriptions of these things are quite consistent as well. Many people have reported seeing flashing lights, oval-shaped discs and triangular objects over the past decade, which are not exactly normal objects to see in the sky.
"They could definitely be extra-terrestrial."
Fellow investigator Harry Sommerville, who leads the East 2 West UFO Society in West Lothian, said that there had been many occasions when he had been unable to explain objects reported above the Lothians.
He said: "My organisation tries to identify what these things are and we always look for a rational explanation. After every sighting we contact the police, MoD and local RAF bases to see if there have been any unscheduled flights and we also track satellites to try to narrow down the possibilities for what they could be.
"But there have been plenty of times when we've been completely stumped and the only explanation is that it's been a UFO. There have been quite a few cases in East Lothian and Midlothian where we've looked at photos and videos and spoken to witnesses but have been left with no other answer than it's been an unidentified object.
"Whether they are alien craft or not is another matter, but they're definitely incidents where no-one has been able to identify what these things are."
Both Edinburgh Airport and the East Fortune airfield, which is currently the base for the Museum of Flight, said they had been unaware of any incidents involving UFOs in the region over the past decade.
However, astronomers at the Royal Observatory said they had occasionally been contacted by members of the public about mysterious objects.
Tim Hawarden, a senior astronomer at the observatory, said that there was "almost always" a rational explanation for UFO sightings.
He added: "I've been involved in astronomy for more than 40 years and in almost all cases where people see unusual things in the sky it is because they have no idea of the scale of the objects they are looking at.
"A professional observer can determine how far away something is and how fast it is going, but a typical eyewitness doesn't have the same knowledge to make a judgement.
"Even if something looks like it is other-worldly, the overwhelming likelihood is that it's been caused by something natural rather than aliens."
A spokesman for the MoD today said: "The MoD examines any UFO sighting reports it receives solely to establish whether there is any evidence to suggest that UK airspace has been compromised by hostile or unauthorised air activity.
"Unless there is such evidence the MoD does not attempt to positively identify what was seen."
Forester maintained he was abducted
THE most famous instance of a UFO sighting in the Lothians occurred on November 9, 1979, when forestry worker Bob Taylor encountered mysterious alien spheres.
The incident was one of the best-documented in the region, and to this day defies rational explanation.
Mr Taylor, pictured, then a forestry worker employed by the Livingston Development Corporation, had parked his truck at the bottom of Dechmont Law, West Lothian. He had walked up the lower slope of the hill with his dog, and as he emerged into a clearing saw a large, circular, sphere-like object about 20ft across.
At the time he said it appeared to be made from a dark metallic material with a rough texture like sandpaper.
As he approached the object, two spheres, each about three feet wide with protruding metal spikes like old naval mines, dropped from the object.
The two spheres rolled towards him and despite his dog barking furiously, attached themselves to his trousers. There was an acrid smell that caused him to choke and he felt a sensation of being grabbed by the side of the legs and tugged forward.
The next thing Mr Taylor remembered was waking up with his head pounding, a sore throat, and a bitter taste in his mouth. He later calculated that he had been unconscious for at least 20 minutes.
The incident is the only case in British history of an alien sighting and became the subject of a criminal investigation.
Mr Taylor died from bronchial pneumonia in March, aged 88.
To his death he maintained that he had been abducted by aliens.
1. April 15 1998, Musselburgh: Two bright jelly fish shaped objects seen “moving in a south-easterly direction”.
2. August 3 1998, Livingston: One bright, star-shaped light which repeatedly dimmed and
3. September 16 1998, Blackridge: One “sparkly” blue-white light described as jumping back and forth in the sky without moving any distance.
4. October 11 1998, Edinburgh: Very large, oval-shaped object “illuminated like the Moon”.
5. November 16 1998, Edinburgh: A white, shining light that made a “whoosh” sound.
6. December 20 1998, Edinburgh: A line of three or four orange lights.
7. December 20 1998, Edinburgh: A bright gold-coloured ball with a tail, described as “comet-like”.
8. December 21 1998, Edinburgh: An object changing colour while hovering in the sky. Described as like green lights or lasers.
9. January 9 1999, Dunbar: One bright light with “red, yellow and green alternating lights on it”.
10. March 29 1999, Tranent: A red, green and blue star shape.
11. November 8 1999, Penicuik: An object that looked like a star but had “blue and red flashing lights”.
12. December 3 1999, Deans, Livingston: Report of an unidentified “object”.
13. February 23 2000, Colinton: Report of a bright oval object with a tail like a kite. Described as moving fast towards the west before dipping and disappearing.
14. March 26 2001, Leith: Two “fuzzy white lights” that appeared to be dancing around each other.
15. December 29 2003, Barnton Park, Edinburgh: A steady bright light in the sky “resembling the front of a helicopter”.
16. March 17 2004, Edinburgh: A fast moving bright light.
17. December 10 2004, Broxburn: A bright orange ball of fire with a tail “five to seven times the diameter of the ball”.
18. December 2005, Haddington: Report of a “UFO”.
19. September 29 2006, East Linton: Report of a “big round swirly thing in the sky”.
20. December 2006, Midlothian: Five orange lights moving slowly across the sky.
21. December 2006, Midlothian: Four small bright red lights moving slowly across the sky
22. December 2006, Midlothian: A “weird light going in all sorts going in all sorts of weird directions”.