1) a common surface feature on the terrestrial planets is a) mountains b) volcanoes c) oceans d) earthquakes 2) which scientist determined the planet's orbital shapes and sizes by triangulation? a) brahe b) galileo c) kepler d) tycho 3) scientists used the keck telescope to learn more about the located at the center of the milky way galaxy a) star cluster b) density waves c) black hole d) solar system 4) when the solar system formed, planetesimals collided and merged to form a) protoplanets b) exosolar planets c) planets d) planetoids 5) how is the heliocentric model of the solar system different than the geocentric model? a) the heliocentric model did not include the motion of other planets and the moon b) the heliocentric model did not include the motions of other planets and the moon c) the heliocentric model has planets going around earth; the geocentric model has planets going around the sun d) the heliocentric model has planets going around the sun; the geocentric model has planets going around earth