In Earth's history there have been many collisions with objects from the solar system.
Comets and asteroids have made violent collisions that have scarred the earth, (Astroblemes). Craters are created when such objects collide with the earth.
The organisation Spaceguard, was formed to catalogue Asteroids that their orbits intersects with the earth. Such asteroids are called " Earth Grazers" .
Significant impacts from asteroids and comets represent a rear danger of extinction of the human race.
Elie Touloupis
11 April 2016