Across
- 3. All planets travel around the Sun in this direction (page 200).
- 6. This is an object in our solar system that orbits the Sun, is massive enough that its gravity compresses it into an approximately spherical shape, but has not swept its orbital region clear of other objects.
- 9. These icy bodies orbit the Sun from very far away and grow huge tails of gas and dust when they get closer to the Sun.
- 12. This, also known as the IAU, was responsible for classifying Pluto and other celestial bodies, as dwarf planets in 2006.
- 13. These are large rocky or metallic bodies, which the largest being the dwarf body Ceres.
- 16. The planets of Mercury to Mars are also classified as _____________ due to their resemblance to the Earth.
- 17. The planets of Jupiter to Neptune are also classified as __________ due to their resemblance to Jupiter.
- 18. Most comets orbit far beyond Neptune in a region of the Solar System known as this.
- 19. These objects are small, planet-like bodies that collide to form our planets!
- 21. This planet's rotational axis is so large that it spins backward, technically known as retrograde rotation. (Page 200)
- 22. This is the classification of the planets that are small rocky bodies with relatively thin or no atmospheres.
- 24. It takes millions of years for an interstellar cloud to collapse and become a rotating disk, known as a ____________________ ____________.
- 25. This process occurs when tiny particles that condensed from the nebula begin to stick together, similar to making a snow ball!
Down
- 1. This celestial body is not classified as a planet due to its small size, composition of ice and rock, and its odd orbit.
- 2. The Sun's second most abundant element is this at 27% (found on page 197).
- 4. This theory of how the Solar System was born states that it originated from a rotation cloud, known as a nebula.
- 5. The Sun is mostly this element at 71% (found on page 197).
- 7. Most asteroids orbit the Sun in this large gap between Mars and Jupiter.
- 8. This is a method of finding an exoplanet, in which an exoplanet's orbit is in front of a star, and thus transits it.
- 10. The modern form of the solar nebula theory proposes that the Solar System was born 4.6 billion years ago from an ___________ ________.
- 11. This is the process of detecting the bending of light from a distant star as the star's light traveled past our Sun. This is a common technique for detecting exoplanets.
- 14. This type of force is the reason why the planets are held in orbit around the Sun and have consistent orbital patterns (page 197).
- 15. This is the classification of the planets that are gaseous and liquid.
- 20. Beyond Neptune is the _________ ________, where objects held here are mostly icy bodies.
- 23. These are known as planets orbiting stars other than our Sun.