| A | B |
|---|
| Solar System | the systemof nine planets and many other smaller objects that orbit our sun |
| Inner Planet | the solid rocky planets closest to our sun--Mercury, Venus, Earth, and Mars |
| Outer Planet | the planets farthest from our sun--Jupiter, Saturn, Uranus, Neptune, and Pluto |
| Mercury | the first planet from the sun and second smallest planet |
| Venus | the second planet from the sun--Earth's twin |
| Earth | the third planet from the sun--the only planet known to support life |
| Astronomical Unit | the average distance from Earth to the Sun 150 million kilometers |
| Mars | the fourth planet from the sun; known as the RED planet |
| Jupiter | the fifth planet from the sun--the largest planet |
| Great Red Spot | a giant, swirling, high pressure gas storm in Jupiter's atmosphere |
| Saturn | the sixth planet from the sun; the second largest planet; best known for its rings |
| Uranus | the seventh planet from the sun; the only planet that lays on its side in orbit |
| Neptune | usually the eighth planet from the sun; has storm-like features |
| Pluto | usually the ninth planet from the sun; the smallest planet |
| Comet | a mass of frozen gases, dust, and rock particles that often develops a bright tails when it passes near the sun |
| Oort Cloud | a cloud of comets surrounding the solar system |
| Meteor | a meteoroid that enters Earth's atmosphere and burns up as it falls--called a shooting star |
| Meteorite | a meteor that does not completely burn up in the Earth's atmospher and strikes Earth's surface |
| Asteroid | a piece of rock, smaller that a planet, that orbits the sun |
