Asteroids the size of the Chelyabinsk meteor strike Earth roughly every 50-100 years, said Richard Moissl, the European Space Agency s head of planetary defence.
In a new article in Science, an astronomer details a new method for searching for asteroids at twilight, a difficult process that is revealing more space rocks in the inner Solar System.
Several hidden planet killers are near-earth asteroids lying between the Earth and the Sun where the glare conceals them, in an area with one of the most lethal corridors in our Solar System.
Astronomer Scott Sheppard, from the Carnegie Institution for Science in Washington DC, says the discoveries of near-Earth objects (NEOs) are only just beginning.