A magnet could help us divert asteroids away from Earth TimothyOLeary/Getty Images We could deflect potentially hazardous asteroids by using an enormous magnet to gently pull them apart. This idea avoids some of the pitfalls of the more traditional kinetic impactor method, which involves smashing something into an asteroid to move it, but it has yet to be tested, so we can’t be sure it would work. The idea is called non-contact orbital velocity adjustment, or NOVA, and Gunther Kletetschka at the University of Alaska Fairbanks presented it at the Lunar and Planetary Science Conference in Texas on 17 March. In his calculations, he applied the NOVA concept to an asteroid called 2024 YR4 , which briefly seemed like it might be on a trajectory to hit Earth or the moon in 2032, although further observations showed that it will pass safely by . The asteroid is small, less than 70 metres across, so it would present a relatively simple target to shift.…