HAZARDOUS ASTEROIDS
It’s one of Hollywood’s favourite disaster scenarios: a chunk of I rock hurtling through space on a collision course with Earth. But this scenario isn’t just science fiction – there really are rocks in space, in the form of asteroids, and some of them do have orbits that cross Earth’s. It’s also no longer science fiction to suggest that a future space mission might be able to avert such a disaster. NASA’s Double Asteroid Redirection Test, or DART, is a mission currently flying through space aiming to test one possible way of doing this. But before we examine it, it’s worth recalling just what asteroids are and why some of them are potentially hazardous to life here on Earth.
Asteroids are essentially just chunks of rock that orbit the Sun like tiny planets. They range in size from a few metres to hundreds of miles across, and there are millions of them in the main asteroid belt between Mars and Jupiter. In smaller numbers, however, asteroids can be found throughout the Solar System. Those that have orbits that come close to Earth’s own orbit around the Sun are called near-Earth asteroids, although that’s a somewhat
