It's Your Planet Trivia Quiz

Answer: Uranus

Ariel is the fourth-largest of the known moons of Uranus, and was discovered (along with Umbriel) on October 24th, 1851 by English astronomer William Lassell. The moon was named for two literary characters: Ariel from Shakespeare's play, "The Tempest", and the sky spirit of the same name from Alexander Pope's "The Rape of the Lock".

Ariel orbits Uranus at a distance of 190,900 km, and it takes 2.52 Earth days to complete one revolution.

Answer: Saturn

Calypso was discovered orbiting Saturn in 1980 at the same time as five other moons, by a team of astronomers (Baum, Currie, Pascu, and Seidelmann). The moon was named after a nymph from Greek mythology (daughter of the Titans Oceanus and Tethys).

Calypso is an irregularly shaped moon, and is co-orbital (as is Telesto) with the larger moon Tethys (appropriately). It takes 1.89 Earth days to complete one revolution of Saturn.

Answer: Mars

Deimos is the smaller of Mars' two moons. It was discovered by the American astronomer Asaph Hall, Sr. on August 12th, 1877. Deimos was named after 'Dread', the companion of the Greek god of war Ares (the counterpart to Rome's Mars).

Deimos orbits Mars at a distance of 23,460 km, and completes one revolution of the planet in 1.26 Earth days.

Answer: Jupiter

Europa was discovered by Galileo Galilei in 1610 along with three other moons, collectively known as the 'Galilean Moons'. Although it is the smallest of the four, it still can boast of being the sixth largest moon in the solar system. All of the Galilean satellites are named after lovers of Zeus (the Greek counterpart to the Roman Jupiter). Europa was the daughter of the king of Tyre in Greek mythology.

Europa orbits at a distance of 670,900 km from Jupiter, and it takes 3.55 days to orbit the planet.

Answer: Jupiter

Io is also one of the four Galilean moons (discovered in 1610 by Galileo Galilei along with Callisto, Europa, and Ganymede). It is the third largest of the Galilean moons, and the fourth largest in the solar system. Io also happens to be the most geologically active object within the system, with over 400 volcanoes. As with Europa, Io was named for a lover of Zeus in Greek mythology.

Io orbits Jupiter at a range of 421,700 km, and needs 1.77 Earth days to complete one revolution of the planet.

Answer: Neptune

Naiad is Neptune's innermost moon, and was discovered by the Voyager 2 probe as it sailed past the planet in early September, 1989. It was officially named on September 16th. Naiad was named for the Naiads of Greek mythology, who were water nymphs associated with sources of fresh water (lakes/pools/rivers, etc).

Naiad is in a decaying orbit at approximately 23,500 km from Neptune, and it takes 0.29 Earth days to complete one revolution.

Answer: Uranus

Oberon was discovered on January 11th, 1787 by the British astronomer William Herschel. It is the ninth largest moon in the solar system, and Uranus' second largest, after Titania. Oberon was named for the King of the Fairies in Shakespeare's "A Midsummer Night's Dream".

Oberon orbits Uranus at a distance of 583,520 km, and it needs 13.46 Earth days to complete one revolution.

Answer: Mars

Phobos is the other (and larger) of the two moons of Mars. It was also discovered by Asaph Hall, Sr., six days after Deimos (on August 18th, 1877). Together, Phobos and Deimos are the god of war's companions, Fear and Dread.

Phobos orbits Mars at a distance of 5,989 km, and it takes 0.32 Earth days to complete one revolution. This is actually faster than the planet rotates, so to an observer from the surface of Mars, it would seem as though Phobos rises in the west and sets in the east.

Answer: Saturn

Titan is the second largest moon in the solar system (behind Jupiter's Ganymede), and was discovered by the Dutch astronomer Christiaan Huygens on March 25th, 1655. Titan was named in 1847 by John (son of William) Herschel for the Titans of Greek mythology, and so were all of the other known Saturnine moons at that time.

Titan orbits Saturn at a distance of 1,221,870 km, and requires 15.94 Earth days to complete one revolution around the gas giant.

Answer: Neptune

British astronomer William Lassell discovered Triton on October 10th, 1846, just over two weeks after Neptune itself was discovered (by Johann Gottfried Galle, who found it based on the mathematical predictions of Urbain Le Verrier). It was named after Triton, the son of the Greek god Poseidon (the counterpart to Rome's Neptune).

Triton orbits Neptune at a distance of 354,759 km, and takes −5.88 days to orbit the planet. Yes, the negative '-' is supposed to be there. Triton is unique among the larger moons of the solar system in that it has a retrograde orbit, which means that it orbits Neptune in the opposite direction to the planet's rotation.