Solar System• A group of

objects in space that move around a central star

Star• A huge,

burning sphere of gases; for example, the sun

Planet• A large object

that moves around a star.

Asteroid

• A small rocky object that moves around the sun.

Comet• A small mass

of dust and ice that orbits the sun in a long, oval-shaped path .

Orbit• The path that

an object such as a planet makes as it revolves around a second object.

Axis• An imaginary

line that runs through both poles of a planet.

Inner Planet• The planets

closest to the sun; Mercury, Venus, Earth, and Mars.

Outer Planet• The planets

farthest from the sun; Jupiter, Saturn, Uranus, Neptune, and Pluto .

Gas Giant• The planets

Jupiter, Saturn, Uranus, and Neptune; which are large spheres made up mostly of gases.

telescope• A device

people use to observe distant objects with their eyes .

Space probe• A space vehicle

that carries cameras, instruments, and other research tools.

constellation• The pattern

formed by a group of stars in the sky .