Across
- 3. a massive ball of extremely hot gas, which is mainly hydrogen
- 4. a giant cloud of mainly hydrogen gas and dust in space
- 6. occur because the Earth is tilted on its axis and it is orbiting the Sun.
- 10. the time it takes for a planet to spin once on its axis.
- 13. groups of stars
- 15. a non-contact force that acts between two masses
Down
- 1. a rocky body orbiting Earth.
- 2. is a measure of the amount of matter in an object
- 5. is a large lump of metals and rock that orbits the Sun
- 7. system the sun and the planets in orbit around it
- 8. a huge collection of gas, dust, and billions of stars and their solar systems
- 9. eclipse when the Earth comes between the sun and the moon
- 11. a smaller lump of ice, dust and rocky material that orbits the Sun.
- 12. the size of the force of gravity acting on an object
- 14. a rocky inner planet, fourth from the Sun