In the 1998 movie Armageddon, Willis plays an oil-drilling engineer who heads a mission to split an asteroid the size of Texas in half with a nuclear bomb.

The two halves of the space rock pass either side of the Earth, saving the human race from annihilation.

But in reality, such a strategy would just not work, a study has shown.

Borrowing a famous phrase from another Hollywood film, Jaws, we would need a bigger bomb.

A team of physics students calculated it would have to be a billion times more powerful than the largest nuclear device ever detonated on Earth, the Soviet Union's 50-megaton hydrogen bomb "Big Ivan".

The asteroid would also have to be detected much earlier than the one in the film to stand any chance of splitting it in time.

Ben Hall, 22, a member of the University of Leicester team, said: "One possible alternative method would be moving the asteroid via propulsion methods attached to it. What is certain is that most methods would require very early detection of such an asteroid and very careful planning in deriving a solution.

"I really enjoyed the film Armageddon and up until recently never really considered the plausibility in the science behind the movie. But after watching it again I found myself being more sceptical about the film in many areas.

"I think that directors attempt to make films scientifically accurate but find they run into a lot of trouble in what can and cannot be done, thus leading to falsification in the science to make movies more interesting or visually appealing to the audience."

The research is published in this year's University of Leicester Journal of Special Physics Topics.

The journal is published every year, and features original short papers written by students in the final year of their four-year Master of Physics degree.

PA