Terrestrial Planets

5. The classification given to the four outermost planets which retained large amounts of hydrogen, helium, and other light elements in gas form
8. The coming together and cohesion of matter under the influence of gravitation to form larger bodies
10. area under the rocky layer of crust where magma is hotter than surrounding magma
12. plate boundary where oceanic crust descends beneath a plate with thicker crust
13. A stream of charged particles radiating outward from the sun at high speed

1. the classification given to the four innermost planets composed mostly of metals and silicate rocks
2. The giant canyon on Mars approximately 10 times longer and six times wider than the Grand Canyon
3. the largest plain, crowned by the largest mountain on Mars
4. The process by which hydrogen is converted to helium in the core of a star
6. The speed a particle needs to reach to leave a planet's gravity
7. source of the Earth's internal energy based on unstable isotopes
9. term used to describe venusian tectonics because it is dominated by the rising and sinking of its mantle and crust
11. The largest mountain in the solar system