Asteroid-seeking missiles could be ready in as little as 20 years, Russian scientists say.

The Makeyev Rocket Design Bureau, which specialises in long-range ballistic missiles, has developed a project to upgrade its fleet – and aims to be ready for target practice on Apophis, as asteroid due to pass Earth in 2036.

Astronomers have found nearly 13,000 "near-Earth asteroids" – relics of the Solar System's birth that hurtle around the Sun close to us. But their orbit isn't as ordered as the planets'. Their path often crisscrosses ours.

And around 1,000 near-Earth asteroids are more than a kilometre in diameter. Should one of those smash into Earth, we could see another mass extinction on the magnitude of the end of the dinosaurs.