pluto

2. year on this is 248 Earth years.
3. relatively small planetoid, smaller than the Earth's moon.
5. had been discovered decades earlier
6. fictional dog that belongs to Mickey Mouse. He is a golden-yellow mutt with a green colla
8. in the Kuiper Belt
10. was discovered while searching for planet X
12. closer to the Sun than Neptune
13. orbit is erratic
16. first vessel devoted to studying Pluto's environment, is the size of a grand piano.
17. of its moons, Charon, is about half
19. considered a planet until 2006
20. only about half the width of the United States.

1. Scientists discovered the Solar System’s third zone
2. was made due to an error in the calculations
4. has a heart shape on its surface
5. an extremely elliptical orbit that's not in the same plane as the eight official planets' orbits
6. just the tip of the iceberg
7. a heart shape on its surface.
9. a dwarf plant
10. dense and rocky, like the terrestrial planets (Mercury, Venus, Earth and Mars)
11. It has not yet cleared the neighborhood of its orbit in space
14. are white mountains
15. is smaller than the Moon
17. than Earth's moon but larger than previously thought
18. closer to The Sun than Neptune