Across
- 2. The largest planet in the Solar System
- 3. A cloud of gas and dust in outer space.
- 5. The element formed by the fusion of two hydrogen nuclei.
- 6. A natural satellite that orbits the earth.
- 9. The attractive force that keeps the planets in orbit around the sun.
- 11. The collapse and explosion of a supergiant star.
Down
- 1. The planet that is farthest from the sun.
- 4. The nuclear process that happens in the core of a star.
- 7. The unit for weight (the force of gravity).
- 8. The planet closest to the sun
- 10. The amount of matter in a body, measured in kilograms.