This initial chapter considered the threats posed by asteroids in space and to
the Earth. Asteroids were defined and exemplified through examination of 99924
Apophis, which will pass close by the Earth on April 13, 2029. The origins of asteroids
in the Kuiper Belt and Oort Cloud were documented and explained, and the role of
iceteroids in the formation of asteroids was mentioned. Asteroid families and groups
were discussed. It was noted that only a small number of the estimated million asteroids
of about one-kilometer in diameter are known. It was documented that smaller asteroids
pose the biggest risk to the Earth and spacefarers. The results of a joint NASA/FEMA
simulation of an East Coast asteroid strike were provided. The danger of asteroid orbital
shift was recognized. It was concluded that a sizeable asteroid impact with the Earth is
inevitable. The significant number of asteroids was revealed through estimates of their
quantification from a variety of sources. Earth-crossing asteroids were defined,
explained, exemplified and quantified. A pair of potentially dangerous asteroids was
considered. The existence of water on Ceres was documented.
Keywords: Asteroid, asteroid belt, asteroid families, asteroid groups, ceres,
Dictionary of Minor Planet Names, Federal Emergency Management Agency,
iceteroids, juno, jupiter, kuiper belt, minor planet, National Aeronautics and Space
Administration, NEAT, NEO Coordination Center, oort cloud, orbital shift, pallas,
quantification, vesta.
