AST F
What contribution did Karl Friedrich Gauss make to the study of asteroids?
Gauss invented a method to calculate the orbit of an object from just three observations.
If Jupiter had not formed, how would that have affected the asteroid belt?
If Jupiter had never formed, the asteroid belt might not exist. Without the effects of Jupiter's gravity, an Earth-sized planet might form in the asteroid belt. Jupiter's strong pull "clears out" the asteroid belt by disrupting the orbits of planetesimals in the belt, ejecting most of them from the solar system altogether.
How does the energy source for Uranus's atmospheric motions compare with those on Jupiter, Saturn, and Neptune?
Jupiter, Saturn, and Neptune are still contracting and giving out energy. Some of this energy powers motions in their atmospheres. Uranus appears to have little or no internal source of heat, and uses only sunlight to power motions in its atmosphere.
Many of the gases in the atmosphere of Titan, such as methane, ethane, and acetylene, are highly flammable. Could the atmosphere of Titan ever catch fire?
No. Oxygen is necessary for combustion of these gases, and Titan's atmosphere contains no oxygen.
The Kuiper belt has a surprisingly sharp outer edge; few Kuiper belt objects are found inside the orbit of Pluto. Why?
Objects at this radius are in gravitatioinal resonance with Neptune and are pulled inward.
How do shepherd satellites operate?
Shepherd satellites operate in pairs to keep ring particles confined to a narrow ring. The outer satellite slows the particles causing them to migrate inward. Then the inner satellite speeds them up again causing them to return to their original orbital distance.
What is the evidence that some asteroids are made of a loose conglomeration of smaller particles?
Some asteroids show large impact craters. Such an impact would have shattered a solid asteroid. But an asteroid that is a loose conglomeration held together by gravity would be able to absorb such an impact. The asteroid might come apart and then be pulled back together again.
What are the Kirkwood gaps, and what causes them?
The Kirkwood gaps are spaces in the asteroid belt where orbital resonance with Jupiter has removed asteroids.
Why are Uranus and Neptune distinctly blue-green in color, whereas Jupiter and Saturn are not?
The atmospheres of both Uranus and Neptune contain substantial amounts of methane, whereas the atmospheres of Jupiter and Saturn do not. Methane absorbs the long wavelength part of the Sun's visible spectrum, allowing the blue and green to pass through.
What is the probable origin of the other (non-Galilean) satellites of Jupiter (Select all that apply.)?
The satellites inside the orbits of the Galilean satellites probably formed from the Jovian nebula. Those outside the orbits of the Galilean satellites are probably captured asteroids.
Although the Voyager and Cassini spacecraft did not collect any samples of Saturn's ring particles, measurements from these spacecraft allowed scientists to determine the sizes of the particles. How was this done?
The trajectories of these spacecraft took them behind the rings so that the radio signal to Earth passed through the rings. The degree to which the signal was scattered indicated the particle size.
Io has no impact craters on its surface, whereas our Moon is covered with craters. Why are they different?
Tidal forces from Jupiter make Io very active geologically, and its surface is constantly reformed by volcanic output. This would erase any craters.
Discuss the main reason why Uranus and Neptune are substantially smaller than Jupiter and Saturn.
Uranus and Neptune formed at a location closer to the Sun and were then moved to their present hydrogen- and helium-deficient region before they could accumulate much hydrogen and helium.
both visited by the DAWN spacecraft
Vesta and Ceres
How does the number of white clouds seen on Uranus and Neptune compare with the number seen on Jupiter and Saturn?
White clouds are due to water and ammonia. These substances exist as vapors in the atmospheres of Jupiter and Saturn but are frozen out of the atmospheres of Uranus and Neptune. Thus, there are more white clouds on Jupiter and Saturn and fewer on Uranus and Neptune.
Is the phrase "dirty snowball" an appropriate characterization of a comet's nucleus?
Yes. A comet's nucleus is believed to be composed of ices plus some dirt, dust, and other solid particles.
In general, how do the asteroids compare with the trans-Neptunian objects?
a loose collection of smaller, interplanetary "rubble."
The orbits of the Galilean moons of Jupiter
all lie in the plane of Jupiter's equator.
What is a plutino?
any object that completes two revolutions of the Sun in the time it takes Neptune to complete three
Where are the majority of the asteroids, or minor planets, found in the solar system?
in a broad region between the orbits of Mars and Jupiter
What is the difference between a meteoroid, a meteor, and a meteorite?
-A meteoroid is a small solid object orbiting the Sun. -A meteor is the flash of light in the sky when a meteoroid burns up in the atmosphere. -A meteorite is a fragment of the original meteoroid that survives the fall through the atmosphere and reaches the ground.
Which of the following are part of our evidence that Triton was captured by Neptune? (Select all that apply.)
-Triton's surface is relatively young. -Triton has a large orbital inclination. -Triton has a retrograde orbit.
1(4). Which of the following is NOT a likely size (diameter) of the particles that comprise Saturn's rings? 1(5). What is the significance of the Roche Limit for a planet? 1(8). Most of Saturn's rings lie inside of Saturn's Roche Limit.
1(4). 500 m: 1 cm, 10 cm, 50 cm, 5 m 1(5). It is the minimum distance at which a moon can orbit a planet without being torn apart. 1(8). T
10(1). Suppose you were standing on Pluto. Describe the motions of Charon and of the Sun relative to your horizon. 10(2). It is sometimes possible to see an eclipse of the Sun on Pluto because Charon's angular diameter is larger than the Sun's as seen from Pluto. How much larger? (Use data from the table below. The center-to-center distance from Pluto to Charon is 19,640 km.) 10(3). Are there conditions under which you would never see a solar eclipse on Pluto? (Select all that apply.)
10(1). Charon is in a synchronous orbit around Pluto, so it would appear motionless in the sky. Pluto has an inclination angle of about 33° to its orbital plane, and it is in retrograde rotation, so the Sun would rise in the west, move across the sky with a maximum altitude of about 57°, and set in the east. 10(2). about 13 times larger 10(3). Yes, if you were on the wrong side of Pluto you would never see Charon at all. Yes, if you were at the wrong latitude the Sun would never pass behind Charon.
11(1). What aspects of Europa lead scientists to speculate that life may exist there? 11(2). What precautions have been taken to prevent contaminating Europa with Earth organisms?
11(1). Europa may have oceans of liquid water under its surface. 11(2). The Galileo spacecraft was sent to a fiery death in the Jovian atmosphere to avoid contaminating the surface of Europa with Earth organisms.
13(1). In order for a solar system object to be considered a planet, it must have a moon. 13(2). There are moons in our solar system which are bigger than Pluto. 13(3). Pluto's orbit is elliptical enough that for roughly 20 years every orbit, it passes closer to the Sun than Neptune. 13(4). Charon is the largest moon in comparison to its planet. 13(5). How was Pluto discovered? 13(6). Pluto's composition is most like 13(9). Currently how many discovered moons does Pluto have? 13(10). Which of the following statements regarding Pluto is FALSE?
13(1). F - This is not one of the criteria. For example, neither Mercury nor Venus have moons. 13(2). T - There are a number of moons, including our own Moon, which are bigger than Pluto. 13(3). T - Due to the eccentricity of Pluto's orbit, its closest approach lies within Neptune's orbit. 13(4). T - Charon is half the size of its planet, Pluto. Most other moons are much smaller than the planets about which they orbit (the next largest would be our Moon, which is one-fourth as big as the Earth). 13(5). Astronomers were looking for a much more massive object and they accidentally found Pluto. Astronomers thought that there was a planet perturbing the orbits of Uranus and Neptune, but it turned out to be a mathematical error. Before realizing this, they discovered Pluto while searching for this supposed planet. 13(6). the comets. Pluto is an icy/rocky body, similar in composition to comets. 13(9). 3 - Astronomers recently discovered two new moons of Pluto, bringing the total up to three moons: Charon, Nix, and Hydra. 13(10). Pluto is the only planet that rotates in a retrograde fashion. - orbit more eccentric, more inclined to ecliptic, composition unlike major planets
13(1). The nucleus of a comet would easily fit within the Earth. 13(3). When a comet is at perihelion, which of its components is closest in size to the diameter of the Sun? 13(4). Using a high-grade amateur telescope, you are lucky enough to observe a comet in the sky. To you, it looks like a bright white ball with a blue streak extending behind it. You correctly identify the blue streak as which of the following? 13(5). At aphelion, a comet consists of which of the following?
13(1). T - The nucleus is typically 10-15 km in diameter. 13(3). the coma - The coma is roughly 75% of the Sun's diameter. The nucleus is much smaller, while the tails and hydrogen envelope are much larger. 13(4). the ion tail - The ion tail glows blue due to emission from carbon molecules. 13(5). a nucleus only - Far from the Sun, only the nucleus remains.
15(1). Suppose you wanted to search for trans-Neptunian objects. Why might it be advantageous to do your observations at infrared rather than visible wavelengths? 15(2). Could you do these infrared observations at an Earth-based station?
15(1). The average surface temperature of Pluto is 50 K. Wien's Law gives as the peak wavelength in its emitted spectrum about 58,000 nm, a wavelength well into the infrared. 15(2). No
15(2). The Huygens probe fell through Titan's atmosphere and landed on its surface. 15(3). What substance flows through the rivers on Titan's surface? 15(4). Why was the discovery of hydrocarbon lakes near Titan's north pole so significant?
15(2). T 15(3). Methane 15(4). It was the first time that liquids were found on the surface of a Solar System body other than Earth.
2(2). Uranus and Neptune appear bluish due to the large concentrations of water in their atmosphere. 2(3). Uranus and Neptune share the same temperature because 2(5). What is unique about Uranus' rotation?
2(2). F - They appear bluish because methane in their atmosphere absorbs red and yellow wavelengths from the Sun, and reflects blue wavelengths. 2(3). Neptune has an internal energy source while Uranus doesn't - Neptune should be colder than Uranus since it is farther away from the Sun, but it is not. Astronomers explain this by the fact that it must be radiating away internal heat. 2(5). Uranus is the only planet tipped over on its side, with a tilt of over 90°. Uranus' rotation axis is tilted 98° relative to its revolution about the Sun, causing extreme seasons, which might be driving seasonal variations in its atmosphere.
3(1). What is the structure of Saturn's rings? 3(2). What evidence is there that ring particles do not migrate significantly between ringlets?
3(1). Saturn's rings are composed of thousands of ringlets that are organized into the major rings. 3(2).The ring particles are not all the same color. Different colors are caused by chemicals, and they tend to segregate with different colors in different ringlets. These colors have remained constant, suggesting that particles do not migrate significantly between ringlets.
The Kuiper belt extends from 30 AU (near the orbit of Neptune) outward to
50 AU.
6(3). Sometimes one or more of Jupiter's moons pass behind Jupiter. 6(5). Io orbits faster than any of the other moons - it takes less than 2 days for Io to make a complete orbit. 6(8). Put the four Galilean moons in order of increasing speed of their orbits around Jupiter: 6(9). When Galileo first saw the moons of Jupiter, what did he think they were?
6(3). T 6(5). T 6(8). Callisto, Ganymede, Europa, Io 6(9). Stars
7(1). Humans have never visited the Jupiter or Saturn systems in person, but we have explored them in great detail with robotic missions. 7(5). Which of the following discoveries was NOT made by the Voyager and Galileo missions?
7(1). T 7(5). Jupiter has a solid, rocky surface.
8(2). Carbonaceous chondrite meteorites likely contain primordial material. 8(3). The most common type of meteorite is which of the following? 8(4). Widmanstatten pattern indicates which of the following? 8(5). Iron meteoroids tend to be homogeneous in composition because of which of the following?
8(2). T - These meteorites are believed to contain material that has remained unchanged since the early days of the solar system. 8(3). stony - Almost 95% of all meteorites that fall to Earth are stony. 8(4). The meteorite was at least partially molten at one time. - The Widmanstatten pattern results when a material is heated, becomes nearly liquid, and then cools slowly. 8(5). They are pieces of an asteroid that differentiated before it broke up. - Iron asteroids are believed to have originated from a differentiate asteroid which subsequently broke apart due to a collision. The iron meteoroid was part of the denser, differentiated core of the asteroid.
All of the Galilean satellites orbit Jupiter in the same direction. Furthermore, the planes of their orbits all lie within 0.5° of Jupiter's equatorial plane. What does this tell you about the idea that the Galilean satellites formed from a "Jovian nebula"?
A "Jovian nebula" would have flattened into an equatorial plane because of rotation before the Galilean satellites formed, just as the solar nebula did. Thus, this observation provides strong support for this hypothesis.
How is it possible to tell that some asteroids are non-spherical even though we do not have images of those asteroids?
An asteroid's shape can be determined by analyzing the reflections of a beam of radio waves sent to it from Earth.
It is thought that Pluto's tenuous atmosphere may become even thinner as the planet moves toward aphelion (which it will reach in 2113) and then regain its present density as it again moves toward perihelion. Why should this happen?
As Pluto approaches aphelion, the temperature drops and the atmosphere freezes out. As it approaches perihelion, the temperature rises and some of the ices evaporate.
Why are asteroids, meteoroids, and comets all of special interest to astronomers who want to understand the early history and subsequent evolution of the solar system?
Asteroids, meteorites, and comets are of special interest to astronomers who want to understand the early history of the solar system because these bodies have undergone fewer changes over billions of years compared with planets and satellites. This unchanged matter still contains information about the early solar system.
Which one of the following statements about asteroids is false?
F: Asteroids are a significant hazard to spacecraft passing through the asteroid belt. T: They are roughly the same sizes, but the trans-Neptunian objects have more ice and less rock. -The asteroids are much larger and have more rock and less ice. -They are roughly the same sizes, but the trans-Neptunian objects have less ice and more rock