Chapter 8 Pluto Comets and Space Debris term

Chapter 8 Pluto, Comets, and Space Debris

term: Asteroid [ click for answer ] 1 of 22

definition: A "minor planet, " a non-luminous chunk of rock smaller than planet-size but larger than a meteoroid, in orbit around a star. [ click for next term ] 1 of 22

term: asteroid belt [ click for answer ] 2 of 22

definition: A region of the Solar System, between the orbits of Mars and Jupiter, in which most of the asteroids orbit. [ click for next term ] 2 of 22

term: coma [ click for answer ] 3 of 22

definition: (a) Of a comet, the region surrounding the head; (b) of an optical system, an off-axis aberration in which the images of points appear with cometlike asymmetries. [ click for next term ] 3 of 22

term: Comet [ click for answer ] 4 of 22

definition: A type of object orbiting the Sun, often in a very elongated orbit, that when relatively near to the Sun shows a coma and may show a tail. [ click for next term ] 4 of 22

term: dust tail [ click for answer ] 5 of 22

definition: The dust left behind a comet, reflecting sunlight. [ click for next term ] 5 of 22

term: gas tail [ click for answer ] 6 of 22

definition: The puffs of ionized gas trailing a comet. [ click for next term ] 6 of 22

term: head [ click for answer ] 7 of 22

definition: Of a comet, the nucleus and coma together. [ click for next term ] 7 of 22

term: Kuiper-belt object [ click for answer ] 8 of 22

definition: An object in the Kuiper belt; many comets and probably even the planet Pluto are examples. [ click for next term ] 8 of 22

term: Meteor [ click for answer ] 9 of 22

definition: A track of light in the sky from rock or dust burning up as it falls through the Earth's atmosphere. [ click for next term ] 9 of 22

term: meteor shower [ click for answer ] 10 of 22

definition: The occurrence at yearly intervals of meteors at a higher-than-average rate as the Earth goes through a comet's orbit and the dust left behind by that comet. [ click for next term ] 10 of 22

term: meteorite [ click for answer ] 11 of 22

definition: An interplanetary chunk of rock after it impacts on a planet or the Moon, especially on the Earth. [ click for next term ] 11 of 22

term: meteoroid [ click for answer ] 12 of 22

definition: An interplanetary chunk of rock smaller than an asteroid. [ click for next term ] 12 of 22

term: Micrometeorite [ click for answer ] 13 of 22

definition: A tiny meteorite. The micrometeorites that hit the Earth's surface are sufficiently slowed down that they can reach the ground without being vaporized. [ click for next term ] 13 of 22

term: minor planets [ click for answer ] 14 of 22

definition: Asteroids. [ click for next term ] 14 of 22

term: Near-Earth Object [ click for answer ] 15 of 22

definition: A comet or asteroid whose orbit is sufficiently close to Earth's that a collision is possible or even likely in the long term. See Apollo asteroids. [ click for next term ] 15 of 22

term: Nucleus [ click for answer ] 16 of 22

definition: (a) Of an atom, the core, which has a positive charge, contains most of the mass, and takes up only a small part of the volume; (b) of a comet, the chunks of matter, no more than a few km across, at the center of the head; (c) of a galaxy, the innermost region. [ click for next term ] 16 of 22

term: Oort comet cloud [ click for answer ] 17 of 22

definition: The trillions of incipient comets surrounding the Solar System in a 50, 000 A. U. (radius) sphere. [ click for next term ] 17 of 22

term: Radiant [ click for answer ] 18 of 22

definition: The point in the sky from which all meteors in a meteor shower appear to be coming. [ click for next term ] 18 of 22

term: shooting stars [ click for answer ] 19 of 22

definition: Meteors. [ click for next term ] 19 of 22

term: sporadic meteor [ click for answer ] 20 of 22

definition: A meteor not associated with a shower. [ click for next term ] 20 of 22

term: Tail [ click for answer ] 21 of 22

definition: Gas and dust left behind as a comet orbits sufficiently close to the Sun, illuminated by sunlight. [ click for next term ] 21 of 22

term: Trans-Neptunian Object (TNO) [ click for answer ] 22 of 22

definition: One of the sub-planetary objects in the Kuiper belt; many people feel that Pluto is one, though it also retains its status as a planet, at least for the time being. [ end of Chapter 8 ] 22 of 22