DSST Astronomy Test Prep Questions and Answers

terrestrial planet (rocky planet) a planet with a solid surface, that is mainly composed of rock and solid materials gaseous planet (gas giants) a planet that has little to no solid surface and is mostly composed of gases dwarf planet a planet that is too small to be considered a full planet light-year the distance that light travels in one year, roughly 6 trillion miles or 63,000 AU parsec a unit of measurement in astronomy, equals to about 206,000 AU or 3.2 light-years magnitude a measure of intrinsic brightness used for celestial objects solar mass used to determine the size of celestial bodies, 1 solar mass is equal to the mass of our sun galaxy ( 3 main types) a group of stars and stellar matter held together by gravitational forces. can contain any where from 10 million stars to 100 trillion stars spiral galaxy a galaxy shaped like a spiral, can have any where from 2 arms to 12 or more elliptical galaxy a galaxy with a spherical shape irregular galaxy a galaxy that does not have a elliptical or spiral shape quasar a galactic nucleus with high luminosity and intense radio waves in the center of a galaxy that has a supermassive black hole bulge bulge (galaxy) the core or heart of a galaxy, containing ether a black hole or a supermassive black hole surrounded by closely packed stars arms (galaxy) the branches of a spiral galaxy dark matter the force that holds matter together,