EAPS 105 HW and Quiz 9

Which planet has rings?

Jupiter, Saturn, Uranus, Neptune

Why do Venus and Mercury have no moons?

Mercury and Venus spin too slow to sustain an orbiting moon - tidal forces would cause their moon to crash onto their surface in a short time

What is NOT the cause of gaps in Saturn's rings?

Mineralogical differences in ring particles

Why is a large part of saturn's moon Tethys yellowish in color?

Saturn's E Ring bombards Tethys leading hemisphere with bright water ice grains from enceladus

How did jupiter acquire the Galilean moons?

The accreated from a ring of material while jupiter formed

Which of our moon's current orbital parameters actually support the conclusion that our moon resulted from a collision with a mars sized object (theta)

The direction of its orbit

9.7. In Wikipedia, look up "Enceladus" and answer the following question: Enceladus is an icy moon of Saturn experiencing tidal forces because of an elliptical orbit due to an orbital resonance with another moon Dione. What are the consequences of tidal heating of Enceladus because of this elliptical orbit?

a. A subsurface ocean b. Geysers c. Tectonically deformed terrains (cracked ice). d. All the above

What is unique about Pluto's moon Charon?

a. Charon is the only moon to have tidally locked its planet.

In Wikipedia, look up "Charon (moon)", read the intro and then scroll down to "Formation" and answer the following question: How did Pluto likely obtain Charon?

a. From a giant impact

In Wikipedia, look up "Rings of Saturn" and answer the following question: Which of the following is a primary cause of gaps in Saturn's rings?

a. Gravitational influence of Saturn's many moon

Why do we suspect an impact origin for Haumea's two moons?

a. Haumea has a rocky mantle and an anomalously thin icy shell, suggesting much of it was blasted off by an impact. b. The moons are almost pure ice (also unusual for Kuiper Belt objects), fitting in with an origin from Haumea's icy shell. c. Haumea is spinning very fast, the reason it is so elongated, which is consistent with an oblique collision. d. All the above

In Wikipedia, look up "Titan (moon)" and answer the following question: What is unique about Saturn's moon Titan compared to all other moons in the solar system?

a. It has lakes on its surface.

In Wikipedia, look up "Io (moon)", read the intro and then scroll down to "Orbit and rotation" and answer the following question: Why is Io in an elliptical orbit?

a. It is in an orbital resonance with Europa and Ganymede.

In Wikipedia, look up "Iapetus (moon)", read the intro and then scroll down to "Equatorial ridge", and answer the following question: Why does Saturn's moon Iapetus have a bulge around its equator?

a. It is the remnant of an oblate shape (stretched spherical shape) from a time when the moon spun very fast. b. Because a ring crashed down onto its surface. c. Icy material welled up along its equator. d. All the above have been suggested.

Which of the following observations support the idea that our Moon formed from a giant impact?

a. Its anorthosite crust b. Its small core c. Its similar chemistry to Earth's crust and mantle d. All the above

What's happening at the Tiger Stripes on Saturn's moon Enceladus?

a. Jets of ice particles are being shot into space.

9.2. In Wikipedia, look up "Giant-impact hypothesis" and answer the following question: Which of the following observations does the giant-impact hypothesis explain?

a. Moon samples indicate that the Moon was once molten. b. The Moon has a relatively small iron core. c. The stable-isotope ratios of lunar and terrestrial rock are identical, implying a common origin. d. All the above

9.9. In Wikipedia, look up "Triton (moon)", read the intro and then scroll down to "Capture" and answer the following question: Neptune is believed to have captured its largest moon Triton. What is the evidence?

a. Moons in retrograde orbits (opposite the spin of the planet) cannot form in the same region of the solar nebula as the planets they orbit. b. Triton's eccentric orbit. c. Triton is nearly identical to Pluto in composition, suggested it originated from the Kuiper belt. d. All the above

In Wikipedia, look up "Rings of Neptune" and answer the following question: Aside from Saturn, which of the other giant planets have rings?

a. Neptune b. Uranus c. Jupiter d. All the above

Which is an indication that a moon was captured?

a. Retrograde orbit b. Highly elliptical orbit c. Non-equatorial orbit d. All the above

In what way is Jupiter and the Galilean moons system like the Sun and planets?

a. The Galilean moons and the planets all formed from an accretionary disc. b. The accretion process of Galilean moons and the planets were all influenced by an ice line. c. The Galilean moons and the planets all have different chemistries from the objects they are orbiting. d. All the above

In Wikipedia, look up "Shepherd moon" and answer the following question: What is a shepherd moon?

b. A moon that clears a gap in planetary-ring material or keeps particles within a ring contained.

Why do shepherd moons like Saturn's Atlas and Pan have fissures and elongated equators?

b. Because tidal forces are trying to pull them apart.

In Wikipedia, look up "Galilean moons", read the intro and then scroll down to "Origin and evolution", and answer the following question: What is the theory regarding how Jupiter obtained its four largest moons, the Galilean moons?

b. From a circumplanetary disk, a ring of accreting gas and solid debris around Jupiter analogous to a protoplanetary disk around a Sun.

In Wikipedia, look up "Ganymede (moon)" and answer the following question: What is unique about Jupiter's moon Ganymede compared to all other moons in the solar system?

b. It is the only moon with a substantial magnetic field.

In Wikipedia, look up "Triton (moon)" and answer the following question: What will be the fate of Neptune's moon Triton?

b. It will cross the Roche limit and become a ring around Neptune.

In Wikipedia, look up "Rings of Saturn", read the intro and then scroll down to "Physical characteristics" and answer the following question: How big are the particles that make up Saturn's rings?

b. Less than 10 m

Which of the following has Saturn's moon Mimas not been compared to?

b. Mickey Mouse

9.1. In Wikipedia, look up "Giant-impact hypothesis", read the intro and then scroll down to "Basic model", and answer the following question: According to the basic model, which of the following is not an inferred characteristic of the collision that led to the formation of the Moon?

b. The collision was a direct hit, not at an oblique angle.

Which of the following observations support the idea that Mars' moons Phobos and Deimos formed from a giant impact?

c. Equatorial orbits

How do we know there are rings around small asteroids like Chariklo and Chiron and the dwarf planets Haumea?

c. From the manner in which starlight dims as these bodies passes in front of them (called occultation).

Which is the only moon in the Solar System with a substantial magnetic field?

c. Ganymede

In Wikipedia, look up "Callisto (moon)" and answer the following question: What is unique about Jupiter's moon Callisto compared to all other large moons in the solar system?

c. It is the largest object in the Solar System that may not be properly differentiated.

What is unique about Neptune's Moon Triton?

c. It is the only large moon in the Solar System to have been captured.

What happens when Neptune's moon Triton migrates inside Neptune's Roche limit?

c. It will be pulled apart and form a ring

In Wikipedia, look up "Roche limit" and answer the following question: What happens to a moon if it migrates inside the Roche limit?

c. It will be pulled apart.

Why is Phobos moving toward Mars?

c. Mars' slow rotation compared to Phobos' orbit causes the tidal bulge to lag behind the direction to Phobos.

If our Moon resulted from a giant impact, how do you explain the fact that the Moon is currently 30 Earth diameters away and does not orbit around the Earth's equatorial plane?

c. Since its origin, the Moon has experienced tidal forces that changed its orbit.

Why is the Moon moving away from Earth?

d. Earth's fast rotation compared to the Moon's orbit causes the tidal bulge to move ahead of the direction to the Moon.

What is unique about Saturn's moon Titan?

d. It is the only body besides Earth to have liquid on its surface.

In Wikipedia, look up "Roche limit" and answer the following question: What is the Roche limit?

d. The distance from a celestial body within which a second celestial body will disintegrate because the first body's tidal forces exceed the second body's gravitational self-attraction.

Which of the following observations is the key factor differentiating a giant impact moon from a co-accretion moon?

d. The moon's mineralogy

In Wikipedia, look up "Rings of Saturn", read the intro and then scroll down to "Physical characteristics" and answer the following question: What are Saturn's rings made of?

d. Water ice

9.4. In Wikipedia, look up "Io (moon)" and answer the following question: What is unique about Jupiter's moon Io compared to all other moons in the solar system?

e. It is the most volcanically active.

What is Charon's likely origin

giant impacts