Across
- 1. Has a density of only 24% of Earth's.
- 4. The planet closest to the sun.
- 5. Planetesimals joined together through collisions to form large bodies.
- 7. Was the first to suggest an Earth-centered model.
- 8. Copernicus proposed a sun-centered model also known as a ________ model.
- 10. Was once the 9th planet but now is a dwarf planet.
- 11. Has an orbit of 687 days around the sun.
- 14. The planets that have their lighter elements (helium and hydrogen).
Down
- 2. Matter is spread through this.
- 3. Small bodies from which a planet originated in the early stages of formation of the solar system.
- 6. The process that formed a new atmosphere.
- 9. Object that circle stars other than Earth's sun.
- 12. Has an axis almost parallel to the plane of its orbit.
- 13. The 3rd planet from the sun.