UN space agency vigilant over threat posed by ‘near-Earth objects’
NEOs are asteroids or comets that come relatively close to the Sun, to about 50 million kilometres from Earth’s orbit. Some of them, ‘potentially hazardous objects’ (PHOs), come even closer – in interstellar terms – with a minimum distance of less than 7.5 million kilometres. Measuring more than 140 meters across, the PHOs have the…