| A | B |
|---|
| solar system | group of nine planets and a sun |
| sun | medium sized star |
| moon | Earth's satellite |
| axis | imaginary line through the center of the planet |
| orbit | the path a planet takes around the sun |
| Venus | greenhouse effect is the cause of it's high temperatures |
| Mars | coated with iron oxide |
| revolution | time it takes a planet to revolve around the sun |
| rotation | time it takes a planet to make one complete turn on it's axis |
| Jupiter | largest planet in our solar system |
| Milky Way | name of our solar system |
| inertia and gravity | keep the planets orbiting the sun in elliptical orbits |
| nebular theory | the solar system was formed from a huge cloud of gas and dust |
| meteorite | part of a meteoroid that strikes the Earth |
| comet | made up of ice, dust, and gas that heat up and form a cloud around the nucleus |
| Saturn | spins so fast, it is flattened at the poles and bulges at the equator |
| Uranus | a gas giant, with a thick atmosphere made of hydrogen, helium, and methane |
| Great Red Spot | a storm on Jupiter |
| asteroid belt | located between Mars and Jupiter |
| Mercury | the planet closest to the sun |
| Earth | liquid water and life |
| Neptune | has rings, a great dark spot, and frozen methane |
| Pluto | atmosphere is methane |
| magnetosphere | magnetic field |
| Io | Jupiter's innermost large moons |
| Europa | ice-covered moon of Jupiter |
| Magellan probe | explored venus |
| winter solstice | Dec. 21 or 22, shortest day of the year |
| summer solstice | June 20 0r 21, longest day of the year |
| Van Allen radiation belts | charged particles are formed as the magnetosphere traps some of the particles in the solar wind |
