Solar system

2. Way galaxy: The spiral galaxy to which our solar system belongs.
3. year: The distance light travels through space in one year- 9.46 Times 10 to the twelth power.
4. unit: a distance equal to 150 million kilometers, or the distance from earth to the sun.
7. law of universal gravitation: A mathematical rule that tells us how the strength of the force of gravity depends on mass and distance.
9. system: The sun, planets, and their moons, and other objects that are gravitationally bound to the sun.
11. A chunk of burning rock traveling through Earth’s atmosphere.
13. An enormous hot ball of gas held together by gravity which produces energy through nuclear fusion reactions in its core.

1. fusion: Reactions which combined light elements such as hydrogen into heavier elements such as helium, releasing energy.
2. A meter that passes through earth's atmosphere and strikes the ground.
5. a cycle of rising and falling sea levels that repeat every 12 hours.
6. An object that orbits the sun but is too small to be considered a planet.
8. A group of stars, dust, gas, and other objects held together by gravitational forces.
10. An object in space made mostly of ice and dust.
12. planets: Jupiter, Saturn, Uranus, neptune.