HOW BIG WOULD A METEORITE HAVE TO BE TO WIPE OUT ALL HUMAN LIFE?

摘要

When it comes to meteorites, the bigger they are, the more havoc they generally wreak. In 1997, University of Colorado geoscientist Brian Toon and colleagues predicted the aftermath of meteorite impacts of various sizes. They found that a space rock half a mile wide would produce an explosion that releases the energy equivalent of up to 100,000 million tons (Mt) of TNT. That's enough to cause widespread blast damage and earthquakes, but nothing too out of line with many natural disasters in the modern age. Once a collision exceeds the 100,000 Mt threshold, you're looking at a catastrophe larger than any in human history. A meteorite a mile in diameter might send enough pulverized rock into the stratosphere to block out sunlight and cause global cooling.