The End of Dinosaurs

The Impact Theory

Large Impact Craters

An impact crater is a large hole in the surface of a planet that is most often caused by a collision with a large space object, such as a comet or an asteroid. All planets and most satellites have impact craters, and even asteroids have impact craters. The Moon is our most obvious example of impacts on a planetary body, as the surface is dotted with hundreds of craters.

To date, scientists have identified over 150 impact craters on Earth. Most have been found on the surface; fewer than a dozen or so are buried or found deep in the oceans. There were probably many more craters, but erosion—from wind, water, or the movement of the continental plates—has erased any evidence of their existence. In addition, there may be many more craters under the thick, vegetative growth of the jungles, in high mountains, or buried deep under sediment on land or in the oceans. The largest known crater, the Vredefort crater in South Africa, is also one of the oldest, with an age of over two billion years. Another large impact crater, the Sudbury in Canada, is a major source of certain metals. Craters on the planet Mars dwarf Earth’s craters. The largest impact crater (also called a basin) on the red planet is Hellas Planitia, measuring 1,243 miles (2,000 kilometers) in diameter.

Name Location Diameter
Vredefort South Africa 186/300
Sudbury Ontario, Canada 155/250
Chicxulub* Yucatan, Mexico 105/170
Manicouagan Quebec, Canada 62/100
Popigai Russia 62/100
Acraman South Australia, Australia   56/90
Chesapeake Bay Virginia, USA   53/85
Puchezh-Katunki Russia   50/80
Morokweng South Africa   44/70
Kara Russia   40/65
Beaverhead Montana, USA   37/60
* Crater thought to be associated, or at least partially associated, with the extinction of the dinosaurs.


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