How have asteroid impacts influenced Earth's history as a planet?

Answer 1

The impact of a massive asteroid has both prompt and long-term effects; depending on the mass and speed of the impactor, the immediate effect would be similar to the explosion of a massive nuclear bomb. (The small asteroid or comet which struck near Tsunguska, Siberia in 1908 was calculated to have been approximately equal to a 10 metagon nuclear explosion!) The blast energy would cause a massive fireball, consuming everything nearby, and flattening trees for miles around.

If the asteroid were to strike water - and the Earth is 3/4 covered with water - it could cause an enormous tsunami wave. There are intriguing suggestions that an asteroid impact in the Indian Ocean 5000 years ago, at a spot now called the Burckle Formation, may have generated tsunami waves that inundated everything from Madagascar to western Australia, and may have provided the background of the Great Flood legends of The Bible and the Book of Gilgamesh.

If the impactor were large enough, it could send so much dust and dirt into the atmosphere that little or no sunlight would be able to warm the planet, causing a worldwide ice age. With no sunlight, plants would be unable to grow; without plants, most large plant-eating animals would also become extinct. This is what we believe happened about 65 million years ago, when an asteroid perhaps 10 miles long struck the Earth near the tip of the Yucatan Peninsula, near the village of Chicxulub , Mexico.

Answer 2

5,000 kilometers from the earth