Across
- 5. The degree of elongation of an elliptical orbit.
- 8. The process by which Earth formed three distinct layers: the core, mantle, and crust.
- 11. The process of volcanic eruptions releasing gases into the atmosphere.
- 13. Meaning sun-centered.
- 14. The tendency of an object to resist being moved or, if moving, to resist a change in speed or direction until an outside force acts upon it.
- 15. A rotating cloud of gas and dust from which the sun and the planets form.
- 16. A region of the solar system that is just beyond the orbit of Neptune and that contains small bodies made mostly of ice.
- 18. The sun and all of the planets and other bodies that travel around it.
Down
- 1. Meaning Earth-centered.
- 2. A small body from which a planet originated in the early stages of development of the solar system.
- 3. Astronomer who believe that planets move in epicycles as they move in larger circles around the Earth.
- 4. This planet is known for its extensive ring system and is the least dense planet in the solar system.
- 6. One of the highly dense planets nearest to the sun; Mercury, Venus, Mars, and Earth.
- 7. The time required for a body to complete a single orbit.
- 9. The planet ______ has seasons like Earth's because its axis tilts at an almost identical angle.
- 10. Any of the primary bodies that orbit the sun; a similar body that orbits another star.
- 12. A planet that has a deep massive atmosphere, such as Jupiter, Saturn, Uranus, or Neptune.
- 17. The law of _________ states that planets orbit the sun in a closed curve whose shape is determined by two foci.