Cosmic Impact: Understanding the Threat to Earth from Asteroids and Comets

As end-of-the-world scenarios go, an apocalyptic collision with an
asteroid or comet is the new kid on the block, gaining respectability only in
the last decade of the 20th century with the realisation that the dinosaurs had
been wiped out by just such an impact.

Now the science community is making up for lost time, with
worldwide efforts to track the thousands of potentially hazardous near-Earth
objects, and plans for high-tech hardware that could deflect an incoming object
from a collis...