I WAS EXPECTING AN EARTH-SHATTERING KABOOM: The Chelyabinsk Lesson: Beware Small Asteroids. “In reconstructing the asteroid from its fragments and recorded evidence of its descent to Earth, scientists estimated that Chelyabinsk was around 62 feet, or 19 meters, in width. Yet even at this (relatively) small size, the space rock caused an airburst equal to about 500 kilotons of TNT. (The largest such airbus of the modern era was about three times that—the 1908 Tunguska asteroid exploded over Russia with the equivalent of 5 to 15 megatons, about 10 times as much.) Scientists have recorded about 1000 objects the size of Chelyabinsk in the area around the Earth, the Wall Street Journal says. However, a meteor expert tells them, there might be a million of them. And according to Space.com, the a historical analysis of impacts suggests Chelyabinsk isn’t exactly a fluke: Asteroids of this size might hit the Earth more often than astronomers had previously thought.”