Across
- 2. Year - A unit of distance used to measure how far light travels in a year (9 letters)
- 4. - The curved path of a celestial object around another due to gravity (5 letters)
- 6. Bang - The theory describing the universe’s explosive beginning (7 letters)
- 9. Planets - Mercury, Venus, Earth, and Mars are collectively called this (12 letters)
- 10. - The explosive death of a massive star (10 letters)
- 11. Shift - The observed increase in wavelength of light from objects moving away (8 letters)
- 13. - Natural satellites that orbit planets (5 letters)
- 16. Giants - Large planets like Jupiter and Saturn, mostly made of hydrogen and helium (9 letters)
- 17. System - The Sun and all objects bound to it by gravity (11 letters)
- 18. - Icy bodies that develop tails when near the Sun (6 letters)
- 19. - Small rocky bodies mostly found in a belt between Mars and Jupiter (9 letters)
Down
- 1. - Large celestial bodies that orbit a star (7 letters)
- 3. - Massive systems of stars, dust, and gas bound by gravity (8 letters)
- 5. - Often called “shooting stars,” these burn up in Earth’s atmosphere (7 letters)
- 7. - The force of attraction between two masses (7 letters)
- 8. - Space rocks that survive the atmosphere and land on Earth (10 letters)
- 12. Effect - The change in frequency or wavelength of a wave relative to an observer
- 14. Planets - The gas giants and ice giants in the Solar System (12 letters)
- 15. - The shape of most planetary orbits (7 letters)
- 17. - Objects, natural or artificial, that orbit a planet (10 letters)