The Many Moons of Our Solar System Quiz

Answer: Ganymede

Ganymede, one of Jupiter's moons, is not only the largest moon with a diameter of 3,280 miles, or 5,262 km, but it's bigger than two planets, Mercury and Pluto. If Ganymede was in its own independent orbit, it would be classified as a planet.

Answer: Io

Io, another one of Jupiter's moons, was first photographed during the Voyager 1 and 2 flybys in 1979. Scientists were pleasantly surprised to see the sulfur eruptions. When the Galileo spacecraft arrived in 1996 it discovered that many surface features had been changed in the previous 17 years.

Answer: Ida

Dactyl was discovered to be orbiting Ida by Galileo in August 1993 as it flew through the asteroid belt on its way to Jupiter. There are 9 asteroids known to have satellites, the most recently discovered as of March 2003 was Hermione.

Answer: Earth

Our moon has no official name other than "Moon," and its translations in other languages. Some people have suggested names, one of the most popular is Luna. By the way, our moon is the fifth largest in the solar system.

Answer: Jupiter

Ganymede, Io, Callisto, and Europa were discovered by Galileo Galilei. Many Jupiter moons have been discovered since then, the most recent discoveries have just been named Callirrhoe, Chaldene, Magaclite, Kalyke, and Erinome. They are named after characters in Greek mythology who are related to Zeus (Jupiter in Roman mythology).

Answer: Uranus

Uranus has at least twenty moons. Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Puck, Miranda, Caliban, and Sycorax are all Shakespearean names. Miranda is one of the most interesting. It has a diameter of only 290 miles, or 470 km, but it has huge fault canyons that are as deep as 12 miles, or 20km.

It's thought that Miranda may have been shattered in collisions with large objects several times in the distant past, and reassembled itself each time.

Answer: Triton

Triton, which looks like a cantaloupe, orbits Neptune in a retrograde orbit, the only large satellite to do so. This means it orbits opposite to the rotation of the planet. Triton is the coldest object in the solar system with a surface temperature of -391 degrees Fahrenheit, or -235 Celsius.

Answer: Mars

Mars has two moons, Phobos and Deimos. With their irregular shape, they resemble potatoes. They are named for the attendants of the Roman war god Mars, their names mean fear and panic. On March 4, 2004, the NASA Mars Rover Opportunity photographed the first ever solar eclipse seen from the surface of another planet when it captured the image of tiny Deimos crossing in front of the sun.
Mercury and Venus have no moons.

Answer: Titan

The Cassini mission arrived at Saturn in July 2004. It was due to release the Huygens probe several months later which landed on Titan, Saturn's largest moon. The Voyager flybys were unable to penetrate Titan's thick atmosphere with their cameras, and scientists are curious as to what lies beneath the clouds.

Answer: Janus and Epimetheus

Despite their odd orbits, these two icy moons never come closer to each other than 13,000 miles or 21,000 km apart. When they do pass that close, their gravitational fields cause them to exchange distances from Saturn, so that one is always slightly closer to the planet than the other.
Nereid, one of Neptune's moons, is so far away from the planet that it takes 360 days for it to complete one orbit.