Science Vocabulary

Unit D  Chapter 9

(13 words)

asteroid belt -  region between Mars and Jupiter where most asteroids are found

comet – a “dirty snowball” orbiting the Sun—a mixture of ices, frozen gases, rock, and dust left over from the formation of the solar system

constellation – patterns formed by groups of stars in the night sky

galaxy - a collection of billions of stars.  Our Sun belongs to the Milky Way galaxy

gravity – the force of attraction between any two objects due to their mass

inertia  - the tendency of a moving object to keep moving in a straight line or of any object to resist a change in motion

inner planet – a planet between the Sun and the asteroid belt (Mercury, Venus, Earth, & Mars)

meteor – a chunk of rock from space that burns up as it travels through Earth’s atmosphere

meteorite – a chunk of rock from space that strikes the surface of Earth or the Moon

outer planet – one of the five planets beyond the asteroid belt (Jupiter, Saturn, Uranus, Neptune, Pluto)

planet – any of the nine major objects that travel around the Sun and shine by reflecting its light

revolve – to move around, or orbit, another object

solar system – the Sun and the objects that are traveling around it