Asteroids are nothing more than giant boulders. This one, called Ida, is more than 52 km(32 miles) long. It Ida collided with Earth, it would destroy all forms of life except bacteria. Waves of fire would sweep over the land. destroying cities and forests. There would be tidal and massive floods lava. The waves, would blot out sunlight for debris blasted into the sky heading this way. It is decades. Fortunately, Ida is not 290 million km safely confined the asteroid belt, from us. (180 million miles) away