Astronomy Vocab
pg 129 Chapter 11
Terms
undefined, object
copy deck
- terrestrial planet
- any of the planets Mecurary Venus Earth or Mars; a planet with a composition and density similar to that of Earth
- protosun
- sun prior to the time when hydrogen fusion began in its core
- asteroid
- any of the rocky objects larger than a few hundred meters in diameter that orbits the sun
- comet
- small body of ice and dust in orbit about the sun. while passing near the sun, a comets vaporized ice egive rise to a coma tails, and a hydrogen envelope
- solar system
- sun planets satellites asteroids comets and related objects that orbit the sun
- average density
- mass of an abject divided by its volume
- asteroid belt
- a 1 1/2 astronomical- unit- wide region between the orbits of Mars and Jupiter in which most of the asteroids are found
- albedo
- fraction of sunlight that a planet, asteroid, or satellite scatters directly back into space
- solar nebula
- cloud of gas and dust from which the sun and the rest of the solar system formed
- protoplanet
- embryonic stage of a planet when it is growing because of collisions with plantersimals
- accretion
- (astronomy) the formation of a celestial object by the effect of gravity pulling together surrounding objects and gases
- crater
- a circular depression on a celestial body caused by the impact of a metroid asteroid or comet or by a volcano
- planetesimal
- primordial asteroid like object from which the planets accreted
- meteoroid
- small rock in interplanetary space
- protoplanetary disks
- disk of material encircling a protostar or a newborn start