- 1. How many natural satellites in the Solar System are known to be massive enough to be close to hydrostatic equilibrium?
A) 15
B) 17
C) 19
D) 22
- 2. How many of the gravitationally rounded natural satellites belong to Saturn?
A) Four
B) Seven
C) One
D) Five
- 3. What is the term used by Alan Stern for gravitationally rounded natural satellites?
A) Major moons
B) Dwarf moons
C) Planetary satellites
D) Satellite planets
- 4. Which is the smallest natural satellite known to be gravitationally rounded?
A) Hyperion
B) Mimas
C) Proteus
D) Phoebe
- 5. Which natural satellite is known not to be gravitationally rounded despite being larger than Mimas?
A) Io
B) Rhea
C) Titan
D) Proteus
- 6. What is the radius of the smallest rounded satellite, Mimas?
A) 210 km
B) 198.2 km
C) 135 km
D) 106.5 km
- 7. Which of these moons is considered to still be in equilibrium today?
A) Io
B) Hyperion
C) Mimas
D) Phoebe
- 8. Why are the moons of trans-Neptunian objects (other than Charon) generally not included in the list?
A) They are all irregular in shape
B) They become solid at a larger size than the moons of Saturn and Uranus
C) They are too small to be seen
D) They have not been discovered yet
- 9. What is the approximate diameter at which TNO moons become solid?
A) 400–500 km
B) 200–300 km
C) 1200–1500 km
D) 900–1000 km
- 10. Which satellite is the fifth largest round satellite of Uranus, despite being the innermost?
A) Triton
B) Titan
C) Mimas
D) Miranda
- 11. What is the reason the Roman numeral system for moons does not always reflect distance from the parent planet?
A) The planets move around the Sun
B) The moons change their orbits over time
C) Scientists update the names every century
D) It follows the order of discovery since 1892
- 12. Which moon is Saturn VII and is not large enough to be round?
A) Hyperion
B) Rhea
C) Mimas
D) Phoebe
- 13. Which of these satellites is mentioned as having a known low density in addition to being a dark body?
A) Ganymede
B) Europa
C) Dysnomia
D) Callisto
- 14. How many round satellites belong to Jupiter?
A) One
B) Seven
C) Four
D) Five
- 15. What is the radius of the non-rounded moon Phoebe?
A) 135 km
B) 210 km
C) 198.2 km
D) 106.5 km
- 16. What percentage of the Solar System's mass does the Sun contain?
A) Almost 99.9%
B) About 99.5%
C) Roughly 90%
D) Approximately 95%
- 17. What is the official classification of the Sun?
A) G-type main-sequence star
B) Gas giant
C) White dwarf
D) Red giant
- 18. How many planets are officially recognized by the IAU?
A) Eight
B) Nine
C) Seven
D) Ten
- 19. Which planet is round but not actually in hydrostatic equilibrium?
A) Mars
B) Venus
C) Earth
D) Mercury
- 20. Where does Ceres orbit?
A) Near the Galactic Center
B) Between Venus and Earth
C) Beyond Neptune
D) In the asteroid belt
- 21. What suggests that many TNOs in the 200–500 km range are not planetary bodies?
A) High surface temperature
B) Rapid rotation
C) Internal porosity
D) Lack of methane
- 22. What molecule, detected by the James Webb Space Telescope, implies methane is resupplied from internal geochemistry?
A) Helium
B) Ethane
C) Carbon monoxide
D) Nitrogen
- 23. Which moon is described as too oblate for its current spin, similar to Quaoar?
A) Europa
B) Titan
C) Triton
D) Iapetus
- 24. Which asteroid is the second-largest and likely had a differentiated interior?
A) Hygiea
B) Vesta
C) Pallas
D) Interamnia
- 25. Which asteroid is the third-largest and appears never to have completed differentiation?
A) Interamnia
B) Pallas
C) Hygiea
D) Vesta
- 26. According to the IAU, what must a planet do besides reaching hydrostatic equilibrium?
A) Maintain a magnetic field
B) Orbit a star smaller than the Sun
C) Clear the neighbourhood around its orbit
D) Possess at least one moon
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