By finding so many asteroids, the scientists finally have enough data to begin doing a statistical census of the population of the killer rocks. Scientists do not know how many potential killer asteroids there are. But they can estimate based on the amount of the sky they have searched and the number they have found there. Previous estimates have been based on a far smaller number of asteroids, making them less accurate, Stokes said. Four hundred of the dangerous asteroids have been discovered since scientists began trying to find them.
None are in orbits that pose a threat for the foreseeable future.
The estimate of 1,100 is significantly larger than the previous best guess of 500 to 1,000, a number published in January based on a smaller number of discoveries with a telescope in Hawaii.