In the glare of the sun, an unknown number of near-Earth asteroids move on unseen orbits. A new generation of infrared telescopes could be our best defense against potential disaster.
A recently discovered asteroid seemed to be on a trajectory to hit Earth next year, but orbit recalculation eventually revealed it will miss our planet.
It’s dangerous to say in a headline that an asteroid is heading towards Earth because asteroid trackers define ‘potentially hazardous objects’ (PHO) as an asteroid or a comet large enough to cause significant regional damage in the event of impact – but 99% of them won’t get close for at least 100 years and ‘close’