Across
- 2. Explains how we know that galaxies are moving farther and farther away from us
- 3. point in Earth's orbit when it's farthest from the Sun
- 8. explains how the solar system formed 4.6 billion years ago
- 10. the Milky Way's nearest neighboring galaxy
- 12. model that says that the planets orbit the Sun
- 14. all existing matter and space
- 15. how elliptical a planet's orbit is
- 16. type of planets made of gas
Down
- 1. point in Earth's orbit when it's closest to the Sun
- 4. shape of Earth's orbit
- 5. idea that the universe started out as a single point in space that expanded
- 6. galaxy we live in
- 7. planet in our solar system closest to the Sun
- 9. type of planets made of rock
- 11. model that says that the moon, sun and planets orbit Earth
- 13. planet in our solar system furthest from the Sun