United States Army Materiel Command. The U.S. Army Materiel Command (AMC) is the primary provider of materiel to the United States Army. The Command's mission includes the research & development of weapons systems as well as maintenance and parts distribution.
A comet is a small, icy object that orbits the sun and has a long tail of gas. Some comets can be seen from Earth every few years, while others pass by once in a person's lifetime. Comets are made of ice, dust, and tiny pieces of rock, but to people on Earth, they look like streaks or smudges across the night sky.
Definition of meteor. 1  1 : an atmospheric phenomenon (as lightning or a snowfall) 2  2a : any of the small particles of matter in the solar system that are directly observable only by their incandescence from frictional heating on entry into the atmosphereb : the streak of light produced by the passage of a meteor.