Geoscience

2. a doughnut-shaped region of icy objects beyond the orbit of Neptune.
3. A steep slope or cliff found at the margin of a flat or gently sloping area, usually against the dip of the rocks
4. Is a measure of how non-circular the orbit of a body is.
5. a fundamental system in condensed matter sciences and the main constituent of gas giant planets
7. a large planet mostly composed of helium and/or hydrogen
10. the area around a star where it is not too hot and not too cold for liquid water to exist on the surface of surrounding planets
12. It contains a great many solid, irregularly shaped bodies called asteroids or minor planets.
13. the orbital motion of a spatial body in a direction that is opposite of what is normal in a given system.
16. When Earth encounters many meteoroids at once
17. a small, icy object that orbits the sun and has a long "tail" of gas.
18. the mean distance between the center of the Earth and the center of the sun. The

1. Earth-like planets made up of rocks or metals with a hard surface.
6. Pluto was officially reclassified as a?
8. is the set of all points the sum of whose distances from two fixed points is constant.
9. a fragment of spatial matter that falls to the surface of a planet
11. a body that could or did come together with many others under gravitation to form a planet.
14. a small body moving in the solar system that would become a meteor if it entered the earth's atmosphere.
15. a space rock that enters earth's atmosphere causing a streak of light to appear in the sky