Small Worlds Trivia Quiz

Answer: Phobos

Phobos is the largest of the twin moons of Mars. It is a small irregular shaped moon with an average diameter of approximately 22.5 km (14 mi). Stickney is a large crater found on the surface of Phobos. The crater measures approximately 9 km (5.6 mi) in diameter, more than a third of the moon's entire surface. Scientists have noticed that Phobos' orbit is slowly decaying and the moon is expected to crash into Mars in about 50 million years. Both Phobos and Deimos (the smaller moon) were discovered by American astronomer Asaph Hall in 1877.

Answer: It orbits around an asteroid

Dactyl was the first moon discovered to be orbiting an asteroid. Its parent asteroid is designated as 243 Ida. Dactyl was discovered by the Galileo spacecraft on February 17, 1994 as the probe was passing through the Asteroid Belt on its way to Jupiter. Dactyl is tiny, measuring about 1.5 km (less than 1 mi) in diameter. 243 Ida, has an average diameter of 31.4 km (19.5 mi) and was discovered by Austrian astronomer Johann Palisa on September 29, 1884.

Answer: Amalthea

Amalthea is the technically the fifth largest moon of Jupiter. It is an irregular shaped moon with an average diameter of 167 km (103.8 mi). Despite being the fifth largest, Amalthea is nearly 3,000 km smaller than Europa, which is Jupiter's fourth largest moon, and the smallest of the Galilean moons, which has a diameter of 3,121 km (1,939 mi). Amalthea was discovered by American astronomer Edward E. Barnard on September 9, 1892 and was named after the foster-mother of Zeus from Greek mythology.

Answer: Pan

Pan is known as a shepherd moon, a small satellite that gravitationally maintains the rings of its parent planet. Pan is located inside Saturn's A ring (the outermost of the main rings) and is responsible for creating the Encke Gap, which defines the moon's orbital path between the rings. Pan itself has an average diameter of 28 km (17 mi). Images of Pan taken by the Cassini probe show that the moon resembles a giant piece of ravioli.

Answer: Calypso

Calypso is a tiny moon with an average diameter of approximately 21.5 km (13.4 mi). Calypso is considered to be a Trojan moon (a small moon that shares the orbit of a larger one). Calypso shares its orbit with the large Saturnian moon Tethys as well as fellow Trojan moon Telesto, which is only a few kilometers larger than Calypso. Calypso and Telesto were both discovered via ground-based observatories in 1980. Calypso shares its name with a type of music that can be heard on numerous Caribbean islands, most notably Trinidad and Tobago where the genre originated.

Answer: Epimetheus

Janus is credited as being discovered by French astronomer Audoin Dollfus on December 15, 1966. Several days later, astronomer Richard Walker first observed the moon that would eventually be named Epimetheus. Janus has an average diameter of 179 km (111 mi), while Epimetheus has an average diameter of 116 km (72 mi).

When Voyager 1 flew by Saturn in 1980, it was observed that the two moons occupied nearly the same orbit. It was later confirmed by astronomers that the two moons swapped orbits nearly every four years coming as close as 10,000 km to one another.

Answer: Perdita ("101 Dalmatians")

Perdita was discovered on May 18, 1999 by astronomer Erich Karkoschka who analyzed images taken by Voyager 2 when it flew by Uranus in 1986. Perdita has an average diameter of approximately 30 km (18.6 mi). Perdita was the mother dog from the Walt Disney film "101 Dalmatians". Ariel, of course, shares its name with the main character of Walt Disney's "The Little Mermaid".

Much like the majority of Uranus' moons, Perdita was actually named after a character that appears in a play created by William Shakespeare. Ariel's name came from the poem "The Rape of the Lock" by Alexander Pope and is also used in Shakespeare's "The Tempest".

Answer: Hippocamp

The Neptunian moon Hippocamp was discovered on July 1, 2013 by a team of NASA researchers using images taken by the Hubble Space Telescope. Hippocamp is estimated to have an average diameter of approximately 35 km (21.7 mi). Hippocamp may lead you to believe that it was named after the hippocampus, which is a part of the human brain and is important in retaining memories.

The name actually comes from a mythical creature, from Greek mythology, that looks like a sea-horse.

Answer: Nessus

Plutonian moons Nix and Hydra were discovered in 2005 using the Hubble Space Telescope. The two moons are close in size to one another, with an estimated diameter of approximately 50 km (31 mi) or less. Two more moons were discovered using Hubble in 2011 (Kerberos) and 2012 (Styx), both of which are even smaller with an estimated diameter of less than 20 km (12 mi). Nessus, however, is considered a centaur, a small Solar System body that crosses the orbits of the outer planets.

Answer: Gabrielle

The dwarf planet Eris and its moon Dysnomia were discovered in 2005 by a team of astronomers from California. Eris became infamous for launching the debate on it and Pluto's planetary status. While the debate on Eris' status went on, the dwarf planet was unofficially named Xena after the main character of the television series "Xena: Warrior Princess".

Its moon Dysnomia was given the temporary name Gabrielle, who was Xena's sidekick in the series. Eris and Dysnomia were later given their official names once the IAU made their ruling. Dysnomia is actually the largest moon featured in this "small" quiz, with an estimated diameter of 700 km (435 mi).