Across
- 2. The planet with the tallest mountain in the solar system.
- 4. A piece of rock that makes a streak of light when it enters the atmosphere.
- 7. A space rock that does not meet the three criteria to be a planet.
- 9. The sun is made mostly of this element.
- 11. A dwarf planet that used to be considered a planet.
- 12. The basic building block of chemical elements.
- 14. Surname of the person who made the first periodic table.
- 15. The name of the most poisonous element in the universe.
Down
- 1. Rocky, airless remnants sometimes called minor planets.
- 3. The element with a chemical symbol 'W'.
- 5. The name of the smelliest element.
- 6. What forms when a star collapses.
- 8. A system of gas, dust and stars held together by gravity.
- 10. The 118th element in the periodic table.
- 13. The planet with a day that is 5832 hours long.