from BBC Monday, 17 August 2009 14:58 UK
In 1996, the Earth was under attack from an alien mothership. Do you remember?
Fortunately, Will Smith was on hand to save the planet. This did happen. At least in cinemas.
Independence Day was the blockbuster film of the year, but the fiction it portrayed may have had an impact on the real world - a huge jump in the number of reported sightings of UFOs.
Documents from the Ministry of Defence released by the National Archives show the department recorded 117 sightings in 1995 and 609 in 1996.
This was also the year when television series The X-Files, about attempts to find extra-terrestrial life, was at the height of its popularity in the UK.
David Clarke, an expert on UFO sightings based at Sheffield Hallam University, believes there is a link between sightings and science-fiction.
"The more that alien life is covered in films or television documentaries, the more people look up at the sky and don't look down at their feet.
"Maybe what they are seeing is ordinary, like an aircraft, but because they are looking for a UFO, they think it is one."
It's difficult to prove, he says, but there is a correlation between films and what people are reporting as strange objects in the sky.
The year with the most sighting was 1978, when Steven Spielberg's Close Encounters of the Third Kind was released in the UK, although the year that ET was packing people into cinemas, 1982, was a year when sightings dipped.
"The lows are also interesting. After 9/11, there were a few years when everyone was distracted by what was going on elsewhere in the world, and then the last couple of years there seems to have been more sightings, possibly due to Chinese lanterns being released at weddings and festivals."
The MoD figures should be treated with some caution, he says, because in later years they only refer to sightings passed to it by other authorities like the police, RAF or coastguards. So they are vulnerable to being distorted if one person or one group of people makes multiple reports.
Before 1973, the cases were investigated and in the preceding 14 years, 223 of the 2,310 sightings remained unexplained, which is one in 10.
The vast majority were discovered to be aircraft (960), satellites and debris (378), celestial objects like planets and stars (221) or freak weather (176).
Of the cases that remained unexplained, says Mr Clarke, most were difficult to investigate with accuracy because they happened long before the investigation.
"But within all this noise, there is a genuine unexplained phenomenon. I don't think it's aliens but there is something peculiar."
Possibly what people are seeing are atmospheric phenomena like ball lightning, he says, which are still little understood.
And maybe having mysteries like these is a good thing for everyone, because it generates an appetite for discovery.
"A lot of people believe in UFOs and want to believe in them as a reaction to scientists, who can now explain where we come from and the beginning of the universe.