Death by Asteroid

摘要

Researchers have identified more than 2,300 asteroids and comets that are big enough to cause considerable damage on Earth and could possibly hit us. These "potentially hazardous objects" look ominous on the flat plot here, but because they travel in three-dimensional orbits, the perfect timing needed to intersect Earth makes the likelihood of collision remote. The symbol sizes shown also deceive; each object is many thousands of limes as small as Earth.