Across
- 2. Gravitational instability in interstellar cloud collapses to form ___.
- 6. The process where a comet's icy nucleus heats up and releases gas, forming a glowing coma and a tail.
- 7. Venus is regarded as the Earth's ___.
- 8. One of the known dwarf planets.
- 10. The fourth planet from the Sun.
- 11. The theoretical region located at the outermost reaches of the solar system, home to many icy bodies and comets.
- 12. Jupiter is primarily composed of ___, helium and putative rocky core.
- 14. The largest moon in the Solar system.
- 15. The planet known as Earth's "sister planet" due to its similar size and composition.
Down
- 1. trans-neptunian objects composed of ___, scattered disk and oort cloud.
- 3. One of the gas composition in Neptune.
- 4. Earth's closest celestial neighbor.
- 5. The region between Mars and Jupiter where many asteroids are found.
- 9. The celestial body that was reclassified as a "dwarf planet" in 2006.
- 13. The larger from the two "ice giants" in the Solar System.