+ May be the
oldest, most primitive bodies in the solar system
preserving the earliest record of material from
the nebula which formed the sun and the planets.
+ Bring volatile
light elements to the planets, playing a role
in forming oceans and atmospheres.
+ Are the most
organic-rich bodies in the solar system providing
ready-formed molecules possibly involved in the
origin of life on Earth.
+ Impact the
Earth and other planets at hypervelocities, causing
major changes in climate and dramatically affecting
the ecological balance, possibly including the
extinction of the Dinosaurs.
+ Are the building
blocks of planetary systems around other stars.
Also, see this
letter written by Fred Whipple.
November 26, 2003