Across
- 2. A large group of solar systems.
- 5. A group of stars which make a pattern in the sky.
- 7. An object that which orbits a planet.
- 9. A natural gas that is found trapped within shale formations.
- 10. A fuel formed by natural processes,like coal.
- 12. It is a large, bright object,e.g.our sun.
- 13. A group of planets orbiting a star.
- 14. everything that exists.
Down
- 1. footprint The amount of greenhouse gases released into the atmosphere by a particular human activity.
- 3. Small, rocky objects which orbit a star.
- 4. A large object which orbits a star.
- 6. A type of hazardous waste that contains radioactive material.
- 8. A gradual increase in the overall temperature of the earth's atmosphere.
- 11. A piece of rock or metal that burns in the sky as it falls.