Across
- 3. The branch of science that deals with celestial objects, space, and the physical universe as a whole.
- 9. A planet that is composed primarily of silicate rocks or metals.
- 10. Found most predominantly in the _____ Belt.
- 12. A cloud of gas and dust in outer space.
- 13. The star around which the earth orbits.
- 14. The solid portion of the earth (distinguished from atmosphere, hydrosphere ).
- 15. An artificial body placed in orbit around the earth or moon or another planet in order to collect information or for communication.
- 16. Planets whose orbit lies outside the asteroid belt.
- 17. The process of growth or increase.
Down
- 1. Cycle of the shape of the illuminated (sunlit) portion of the Moon.
- 2. A large planet of relatively low density consisting predominantly of hydrogen and helium
- 4. Planets whose orbit lies within the asteroid belt.
- 5. A celestial body moving in an elliptical orbit around a star.
- 6. The trapping of the sun's warmth in a planet's lower atmosphere due to the greater transparency of the atmosphere to visible radiation from the sun than to infrared radiation emitted from the planet's surface.
- 7. All the waters on the earth's surface
- 8. The collection of eight planets and their moons in orbit around the sun, together with smaller bodies in the form of asteroids, meteoroids, and comets.
- 11. When near the sun, a “tail” of gas and dust particles appears.