Moons Trivia

1. The four moons discovered by Galileo are among the largest natural satellites in the Solar System, but which is the largest of the four of them?

From Quiz Everything in its Right Place - Galileo's Moons

Answer: Ganymede

Ganymede is the largest of the four Galilean moons, and the largest natural satellite in the Solar System. Its orbit around Jupiter puts it as the seventh closest, and the third closest of the Galilean group, as well as it creating an orbital resonance with two of its fellows - for every orbit Ganymede makes, Europa makes two and Io four. Ganymede's surface is a mix of older, darker regions with abundant impact craters, and lighter, younger regions with an extensive system of grooves and ridges, believed to have been created by tectonic activity caused by tidal heating, a process caused by Ganymede being pulled and flexed as a result of Jupiter's gravity.

From Quiz Moons in our Solar System

Answer: Mercury and Venus

Most of the planets and dwarf planets in our solar system have moons. However, neither Mercury nor Venus have their own natural satellite. Astronomers have a few theories about how moons come to be. Some feel that they are large space rocks that have been floating around and are captured by a planet's gravitational pull. Another theory is that a large object smashes into the planet at one time, with the resulting debris forming a moon. Finally, others theorize that moons form by coming together a bit at a time, slowly accumulating layers of material. In the case of Venus, some scientists theorize that it once did have a moon that was caused by being smashed by a large chunk of space rock, and that it was slowly drifting away from the planet. Then, Venus was smashed again. This, according to the scientists, resulted in Venus reversing its spin which resulted in the planet attracting its moon until there was a collision between the two that destroyed the moon. Of course, this is all theory, but it does sound like a good explanation for why Venus does not have a moon and spins in the opposite direction than all other planets in our solar system.

From Quiz Small Worlds

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.

From Quiz Ganymede: a Mighty Moon

Answer: Galileo Galilei

Galileo, using an early telescope, observed a set of heavenly bodies near Jupiter in 1609/1610 and thought they were fixed stars. After observing them for several days, he realized were not fixed stars, but instead were in orbit around Jupiter. He initially named them the Cosmian Stars or Medician Stars, in honor of Cosimo de Medici, ruler of Tuscany. Over time, the suggestion of Simon Marius and Johannes Kepler to name them after some of the lovers of Jupiter, King of the Roman gods, would take hold. The four moons would be called Ganymede, Europa, Io, and Callisto. Ganymede was a beautiful mortal whom Jupiter claimed to serve as his cupbearer. He would grant Ganymede eternal youth and immortality. Galileo Galilei (1564-1642), in addition to his extensive work in astronomy, also made contributions to engineering and physics.

From Quiz Lunar Lore

Answer: Impact theory

Until 1984 there were different contested hypotheses about the origin of the Moon, until the impact theory prevailed, because it reconciles most of the available facts. It posits that, roughly 4.5 billion years ago, the young Earth had no Moon, when a rogue planet, about the size of Mars, hit it, vaporizing most of itself and a chunk of the Earth. Solid particles orbiting the Earth aggregated, eventually forming the Moon. Fission theory (championed by George Darwin, son of Charles)suggested that the Moon split off from proto-Earth when still in liquid state. Capture theory stated that the Moon was formed independently and was later captured by Earth's gravity. Coaccretion theory says that the Moon and Earth were formed together out of the same material.

From Quiz The Moons of Neptune

Answer: Triton

Triton did not receive its name until Camille Flammarion proposed it in his book "Astronomie Populaire" in 1880. Even then, it was still called 'Neptune's Moon', or 'the satellite of Neptune' until Triton came into popular use in the 1930s. Triton, of course, is the son of Poseidon of Greek mythology, and Poseidon is the Greek equivalent of the Roman god Neptune. Astronomers believe that Triton was captured into Neptune's orbit, largely due to the fact that it has a retrograde orbit, meaning that it goes around Neptune in the opposite direction of the planet's rotation. Triton is the seventh largest moon in the solar system (sixteenth largest overall), and it has more mass than every moon that is smaller than itself, combined. With numbers, Triton is 2,700 km in diameter, and orbits at a distance of 354,759 km (from the centre of Neptune).

From Quiz Titans and Giants

Answer: Nitrogen

Where Earth's atmosphere is 78.1% nitrogen (and 20.1% oxygen), the atmosphere of Titan is 98.4% nitrogen. Titan is the only moon known to have a significant atmosphere. Its atmospheric pressure is actually greater than that of Earth's, and Titan's lower gravity means that the atmosphere extends out further than Earth's. When Titan was first discovered, it was believed to be larger than Ganymede (one of the Galilean moons of Jupiter and the largest moon in the solar system), but the largely opaque atmosphere made observers believe it had a larger diameter than it actually did. Titan is also unique among the moons of the solar system in that it has an active liquid cycle, with clouds, precipitation, lakes and rivers (of liquid methane). As mentioned, Titan is very large as moons go, with a diameter of 5,152 km. It orbits beyond the E Ring at a distance of roughly 1,200,000 km from the center of the planet.

From Quiz Looking up at Psamathe

Answer: Troilus and Cressida

Cressida was discovered in 1986, in images taken by Voyager 2. It has a diameter of 82 km and belongs to the Portia Group of Uranus satellites which include Bianca, Desdemona, Juliet, Portia, Rosalind, Cupid, Belinda and Perdita, all names from William Shakespeare's plays. The story of Cressida is a very sad one. She was a Trojan woman, a daughter of the priest Calchas, who was in love with king Priam's youngest son, Troilus. When Cressida was forcibly sent to the Greeks, she was pursued by Diomedes and betrayed Troilus's love.

From Quiz The Galilean Moons

Answer: 1610

Galileo Galilei lived from 1564 until 1642 and was a big influence in the Renaissance. According to Wikipedia, Galileo has earned a few pretty significant monikers: the "father of modern observational astronomy", the "father of modern physics", the "father of science", and the "father of modern science". Finding moons orbiting Jupiter essentially disproved geocentrism (all planetary bodies orbiting the Earth), and Galileo became a proponent of the heliocentric model (the planets orbit the sun, and moons orbit the planets). It didn't sit well with many people, and especially not with the Church.

From Quiz Fear and Dread

Answer: Asaph Hall

The discoveries were made nearly a week apart on August 12th and 18th at the US Naval Observatory in Washington, DC. Asaph Hall thought he had seen a moon on August 10th, but could not confirm it because of bad weather, delaying the official discovery until the 12th. While showing his new discovery to a colleague late on the 17th into the 18th, Hall discovered a second moon. The names Phobos and Deimos came from Book XV of Homer's "Iliad".

From Quiz Inconstant Moons?

Answer: Leda

'fLED Across'. Leda was the queen of Sparta. Zeus, in the form of a swan, fathered two children with her: Pollux and Helen of Troy.Leda is the smallest of Jupiter's moons. 'Thankee-sai' to Stephen King for the memorable sentence that begins one of my favorite tales,"The Gunslinger". Not only a good book but the beginning of an incredible series. Check it out if you want a good read.

From Quiz Planets and Moons

Answer: Proteus

Both Proteus and Triton are sea gods, and sons of Poseidon, but Proteus is the one who can foretell the future and change his shape. He actually changed his shape so he wouldn't have to foretell the future.

From Quiz Astrogeology I-- Rocky Planets and Moons

Answer: The interior of the planet shrank and cooled

Small bodies tend to cool faster than larger bodies. As the smallest rocky planet, Mercury was the first to cool. As the interior cooled it contracted. The crust hardened first, and so when it shrank, it cracked to form the large thrust faults. Some are 500 km long and 2 to 4 km high!

From Quiz Moons of Uranus

Answer: Oberon

Oberon was the king of the fairies in the play "A Midsummer Night's Dream".

From Quiz "Sea" the Moon

Answer: Sea of Rain

The Sea of Rain is the biggest "sea" on the moon. It can be seen in the upper left hand corner of the moon and is directly attached to the Bay of Rainbows which sits on its top left hand side.

From Quiz The Many Moons of Our Solar System

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.

From Quiz Moon Rocks

Answer: Apollo

All the Apollo missions which attempted to land on the moon successfully did so, except for Apollo 13.

From Quiz Our Moon

Answer: 238,000 miles

The Moon is actually 238,857 miles away. That's pretty far, but still close enough to influence the Earth with tides, etc.

From Quiz Everything in its Right Place - Galileo's Moons

Answer: Io

Io is the innermost of the four Galilean moons, taking just 42 hours to complete an orbit of Jupiter. Because Io is in an orbital resonance with Europa, the next of the Galilean moons out, completing two orbits for Europa's one, it is subject to extreme tidal forces between Europa and Jupiter. These cause a phenomenon called tidal heating that has resulted in an extreme level of volcanism on the surface. As a result, unlike other similarly sized bodies in the Solar System, Io is virtually devoid of impact craters as its surface is being constantly remade by volcanic eruptions.

From Quiz Moons in our Solar System

Answer: 5th

The Earth's moon is our only natural satellite. It is the fifth largest moon in the solar system, and is about 240,000 miles (385,000km) away from the Earth. The Moon helps to keep our planet steady on its axis, which in turn prevents it from wobbling and stabilizes our climate. It is thought that the Moon got its name in medieval times before Galileo made his observations of other moons in the solar system. In medieval times, people simply thought that it was the only moon anywhere.

From Quiz Ganymede: a Mighty Moon

Answer: Mercury

Ganymede has a diameter of 3,273 miles. (By comparison, the distance from Seattle to Miami is 3,318 miles.) Mercury is slightly smaller with a diameter of 3,032 miles. The diameter of Mars is 4,212 miles. Interestingly, though Mercury is smaller in terms of diameter, because of differing composition, it is approximately twice as massive as Ganymede. In comparison to many of the smaller moons of Jupiter, Ganymede is large enough, and massive enough, to have a roughly spherical shape. From 1930 to 2005, we would have had to add Pluto to the list of planets smaller than Ganymede. Though it is currently classed as a dwarf planet, Pluto is significantly smaller than Ganymede, with a diameter of 1,477 miles.

From Quiz Teardrops from the Moon

Answer: Asaph Hall

Although there had been speculation since the discovery of Jupiter's moons that Mars also had moons, thanks to Kepler's misinterpretation of a comment by Galileo (actually about Saturn's rings), it was not until August 1877 that the American astronomer Asaph Hall discovered Phobos and Deimos. He first noticed an object by the side of the planet, and realised that it was moving along with Mars. This object turned out to be Deimos, and Phobos was discovered soon after. There's even a crater on Phobos (the larger of the two moons), the Hall crater, named after him, as well as the asteroid 3299 Hall.

From Quiz Lunar Lore

Answer: They would be lower

The Earth would still have tides even without the Moon, due to the gravitational pull of the Sun, but they would be only about one third of the height of the tides we are used to.

From Quiz The Moons of Neptune

Answer: Gerard Peter Kuiper

Gerard Kuiper discovered Nereid through photographic plates from the 82-inch telescope at the McDonald Observatory in Texas, USA on the 1st of May, 1949. Following the pattern established by the names Neptune and Triton, Kuiper suggested Nereid as the name of this new moon, after the sea-nymphs who attended Poseidon. Nereid is an irregular moon with an eccentric orbit, but it does orbit in a prograde direction. It is the next moon out from Triton, but it orbits MUCH further out. Where Triton's semi-major axis is at 354,759 km, Nereid's varies between (approximately) 900,000 km and 6,000,000 km (the largest such variance of any observed moon).

From Quiz Looking up at Psamathe

Answer: Neptune

Galatea is an irregularly shaped inner moon of Neptune. It orbits the planet every 10 hours and 18 minutes in a spiral motion. This means that it will eventually impact Neptune and break up in its atmosphere or become a planetary ring. All the moons of Neptune are named after minor Greek and Roman sea deities.

From Quiz The Galilean Moons

Answer: Medici

Galileo was the tutor of Cosimo de' Medici between 1605 and 1608, when Cosimo was a teenager (he was born in 1590). His father's death in 1609 vaulted Cosimo to the position of Grand Duke of Tuscany, a position he held for 11 years. Galileo made his discovery only a year into Cosimo's reign, and he wanted to curry favour with his former pupil to hopefully gain a patron. The Grand Duke's secretary, however, thought it might be better to honour the whole family, so Galileo settled on the name Medicea Sidera (the Medician stars) instead.

From Quiz Shakespearean Moons

Answer: Miranda

The exact height of the tallest cliff in the solar system is hard to measure given that it is situated on one of the moons of Uranus, a very long way away! Different sources provide estimates ranging from 5 km (3 miles) to 20 km (12 miles). Regardless of the exact figure, it is clearly very tall - Mount Thor, which has one of the highest vertical drops on Earth, is a mere 1.4 km (0.9 miles) high. Verona Rupes is named after the city in northern Italy that was the setting for three Shakespeare plays ('Romeo and Juliet', 'The Two Gentlemen of Verona' and 'The Taming of the Shrew') - although oddly enough it doesn't feature anywhere in the 'The Tempest'. A rupes is the name given to escarpments found on various bodies of the solar system. Miranda was discovered in 1948 by the Dutch-American astronomer, Gerard Kuiper, whose name has famously been given to the Kuiper Belt - the area of space beyond the eight planets filled with numerous small bodies and dwarf planets, such as Pluto. Julia, Lucetta and Silvia are all female characters from 'The Two Gentlemen of Verona'.

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