Asteroid surveys are on the hunt for ‘city killers’
This week, astronomers announced the discovery of three previously unknown near-Earth asteroids that had been hiding in the glare of the Sun — and one of them is a giant. At nearly a mile (1.5 kilometers) across, it is big enough to cause planet-wide destruction if it hit the Earth, though it won’t come anywhere close enough to be a threat for a hundred years or so.
The search for potentially hazardous asteroids like this one has ramped up in recent years, with multiple ongoing efforts to identify and catalog large space rocks passing close by. From twilight observations from the ground to space-based telescopes peering into hard-to-see regions of the sky, these programs are focused on identifying potentially dangerous asteroids as...