Asked by: Richard Green, Peterborough
There are probably several million asteroids with the potential for smashing into planet Earth. But very large asteroids, which would have catastrophic consequences if they hit us, are thankfully very rare. Astronomers estimate that one of these monster asteroids (like the one that wiped out the dinosaurs) should fall to Earth once every 100 million years or so.
An object about 100m across should arrive every 1,000 years, although thousands of tiny meteoroids land on Earth each day. However, most go unnoticed because they fall in unpopulated areas or into the sea. The chances of you being killed by an asteroid are very small indeed – must smaller than the risks you take driving a car or crossing the road.