Hundreds of people took to Twitter over the "bright light".
One user, called The Observatory, tweeted: "Best thing I have seen in 30 years observing the sky."
Most sightings were in the North. Durham Police said people reported a "bright light or a fire" at about 9.45pm.
Forces across Scotland had similar calls.
No planes were reported to be in trouble, and the Met Office reckoned it had solved the mystery. It said: "We believe it was a meteorite."
Gary Fildes, director at Kielder Observatory, Northumberland, said he was with a group of people who went "absolutely mental" when they saw the meteor and asked him if it was "going to end life on Earth".
Mr Fildes was hosting a northern lights seminar at the observatory for around 40 people when they spotted the fireball for 30-40 seconds.
He said: "We got an incredible view. It was phenomenal.
"They went absolutely mental. I was getting questions about what it is and is it going to end life on Earth? It was massively exciting."
Mr Fildes, who has been an astronomer for 30 years, added: "I've never seen anything like that in my life.
"Trying to nail down the origin of the object will not be easy. It's open to conjecture."
Adrian West, of Meteorwatch, said he spotted the meteor in Berkshire and believed it could have gone down in the English Channel or the Bay of Biscay.
Mr West told the BBC: "It had a very bright orange nucleus and a green tail. It was seen by hundreds, maybe thousands of people."
Meteors are particles from space that burn up in a streak of light as they enter the Earth's atmosphere, whereas meteorites are larger objects that survive the trip and reach the surface of the Earth.
Dr David Whitehouse, an author and astronomer, said: "Judging by its brightness, it may have been large enough to survive and hit the ground but until people work out its trajectory we won't have any idea where it might have come down."
Dr Whitehouse said the object was about the size of a fist and was probably the debris of a planet that never properly formed.
He added: "It's a chunk of rock that's probably come from somewhere between Mars and Jupiter and has been in space for thousands of millions of years.
"There are tens of thousands of bits of rock and grains of sand orbiting between Mars and Jupiter. Some of it comes out of that orbit and some of it hits the Earth."
Anyone know anything (in addition to what was reported by the Gettysburg Times, August 25, 1995) about the multiple-area reports of fireball sighting, that 'coincidentally' happened around the same time as an empty trailer in Ontario, Canada, exploding? Thanks. Great video, BTW
|362 days ago|
|Where did this happen?||In the sky|