An asteroid 1.5 km across is no joke. Even a much smaller one, about the size of a house, can explode with more power than the first nuclear weapons. When an asteroid is greater than 1 km in diameter, astronomers call them “planet-killers.” The impact energy released from a ...
Read more: Three New Potentially Hazardous Asteroids Discovered, Including a big one That Measures 1.5 km Across