IMPACT : Death from Above
Giant impacts could have grave consequences on life on Earth; they almost surely have in the past. It is generally accepted by the scientific community that an asteroid about 10 kilometers in diameter crashed into Earth 65 million years ago, killing off more than half the species of life, including the dinosaurs. Every land animal over 50 pounds was believed killed. Recent geologic and geophysical evidence suggests that it was an exceptionally severe blow. The crater this severe impact caused is called Chicxulub and located in the Yucatán peninsula. It may be the largest impact basin to form on Earth in the past billion years.
The frequency of significant comet impacts is estimated to be one in every 300,000 years. One of the most powerful supercomputers in the world was used to calculate the catastrophe a comet would have. The calculation assumed a one-kilometer-diameter comet weighing about a billion tons, traveling 60 kilometers per second and striking Earth's atmosphere at a 45-degree angle. This simulated body is actually rather small as comets go; Comet Hale-Bopp weighs about 10 trillion tons.
| Meteorite Impacts | | More About Comet Impact | | The Simulated Effects of a Small Comet |
| What Killed the Dinosaurs?? | | Can Impact be Avoided?? |
(c) 1998 William Jessee