Planetary Bodies
 
 
An asteroid about to impact the Earth Impact Imminent (2009)
High above the Earth, an asteroid a few kilometres across enters our planet's atmosphere at a speed of several kilometres per second. At that velocity, it is only a matter of seconds before the asteroid smashes into the surface, vaporising both itself and the ground around the impact site, hollowing out a vast crater, and causing widespread disaster.
See also
An asteroid impact ends the reign of the dinosaurs
An asteroid impacting the Earth
Asteroids or comets impact the Earth at night