It was the student prank that apparently fell to earth after experts dismissed a meteorite crash in Latvia as an elaborate hoax today.

Dramatic video of a fireball at the bottom of an impact crater on farmland outside the town of Mazsalaca was shown all over the world, taken by a group of film students who said that they had heard the meteor strike.

But experts who examined the scene were less star-struck. Dr Ilgonis Vilks, chairman of the scientific council at the University of Latvia's Institute of Astronomy, said: "It's a fake. It's very disappointing, I was full of hope coming here, but I am certain it is not a meteorite."

Setting aside the astronomical odds of a group of film students happening to be at the ready when a meteorite hits the Earth, Dr Vilks said that several other tell-tale signs had given the game away.

There was green grass inside the crater despite the intense heat supposedly generated by the meteorite. The impact crater, initially reported as 10 metres deep, was actually only 3 metres including a lip of soil a metre high around the hole.

Dr Vilks said that there was neither ejected material from the hole nor any fragments of meteorite on the surrounding land. Finally, there was the flaming "meteorite" itself.

"It's a ball of clay that was burning. We took some samples from it and geologists from the university will examine it," Dr Vilks said. "There was a small blast heard by local people but this was not strong enough to create the crater and there's only a small area in the hole that is burnt."

Dainis Ozols, a nature conservationist who also examined the scene, said that he believed somebody had dug the hole and burnt a pyrotechnic compound at the bottom to make it appear like a meteorite crater.

The alert was first raised on Sunday evening by Ancis Steinbergs, who said that he had been out filming for a university project with his girlfriend and a fellow undergraduate. He was refusing to answer his telephone tonight to answer questions about the experts' assessments.

He had earlier told The Times that the trio had heard a loud roaring sound "like an airplane falling from the sky" seconds before the alleged meteorite hit the field behind some trees.

Mr Steinbergs said: "We saw something burning in the sky like a ball and it was moving very fast and then there was a loud noise. We went to find it and there was this big hole with fire burning in it.

"It was so hot that the camera was misting up. We thought it was really dangerous because there might be an explosion."

Video taken by the group showed them approaching the lip of the crater and filming the glowing hot "meteor" at the bottom as they talked excitedly among themselves. The clip bears similarities in style to the Blair Witch Project, a 1999 film based on supposedly "amateur" footage shot by three missing film students.

Mr Steinbergs said that he called Latvia's Fire and Rescue Service. Inga Vetere, a spokeswoman, said that fire crews had attended the site and cordoned it off. Tests had recorded normal levels of radiation and nobody had been hurt.

Local news agencies reported that the landowner, Larisa Gerasimova, had been quick to capitalise on interest surrounding the crater and had begun to charge curious visitors $2 to view the site.

Earth is bombarded by thousands of small celestial objects every year but most burn up in the atmosphere before they reach the surface. The last recorded meteorite strike on land was in 2007 near Lake Titicaca in Peru, when it left a crater 12 metres wide (40ft) and five metres deep (15ft).