Astro Midterm Questions
2) What does angular resolution measure?
A) the angular size of the smallest features that the telescope can see
B) the brightness of an image
C) the size of an image
D) the number of electromagnetic waves captured by an image
3) What is the angular resolution of the human eye?
A) about 1 degree
B) about 1 arcsecond (1/3600 of a degree)
C) about 1 arcminute, or 1/60 of a degree
D) about 1 milliarcsecond
4) What is a CCD?
A) It is an electronic detector that can be used in place of photographic film for making images.
B) It is an abbreviation for the world's largest operating telescope.
C) It refers to any kind of instrument that can be hooked up to a telescope.
D) It is a unit used by astronomers to measure angular resolution.
5) Which of the following statements best describes the two principle advantages of telescopes over eyes?
A) Telescopes can collect far more light with far better angular resolution.
B) Telescopes can collect far more light with far greater magnification.
C) Telescopes collect more light and are unaffected by twinkling.
D) Telescopes have much more magnification and better angular resolution.
6) Which of the following statements best describes the difference between a refracting telescope and a reflecting telescope?
A) A refracting telescope uses a transparent glass lens to focus light while a reflecting telescope uses a mirror to focus light.
B) A refracting telescope produces refracted images while a reflecting telescope produces reflected images.
C) Reflecting telescopes make much clearer images than can refracting telescopes of the same size.
D) It is much easier to make a large refracting telescope than a large reflecting telescope.
7) What do we mean by the diffraction limit of a telescope?
A) It describes the farthest distance to which the telescope can see.
B) It is the angular resolution the telescope could achieve if nothing besides the size of its light-collecting area affected the quality of its images.
C) It is the maximum size to which any telescope can be built.
D) It describes the maximum exposure time for images captured with the telescope.
8) Which of the following is not one of the three main categories of observation generally used by astronomers?
A) filtering to look at just a single color from an object
B) timing to track how an object's brightness varies with time
C) spectroscopy to spread an object's light into a spectrum
D) imaging to get a picture of an astronomical objects
9) Suppose you want to determine the chemical composition of a distant planet or star. Which of the following will be most useful to have?
A) high angular resolution
B) high turbulence
C) a radio telescope
D) high spectral resolution
10) Which of the following is always true about images captured with X-ray telescopes?
A) They are always shown with colors that are not the true colors of the objects that were photographed.
B) They always are made with adaptive optics.
C) They show us light with extremely long wavelengths compared to the wavelengths of visible light.
D) They always have very high angular resolution.
E) They are always very pretty.
11) What do astronomers mean by light pollution?
A) Light pollution is a type of air pollution created by lightweight gases such as hydrogen and helium.
B) Light pollution is light from human sources that makes it difficult to see the stars at night.
C) Light pollution means contamination of light caused by chemicals in the Earth's atmosphere.
D) Light pollution is a term used to describe the appearance of the sky in regions that are crowded with stars.
12) Which of the following effects is caused by atmospheric turbulence?
A) twinkling of stars
B) light pollution
C) magnification of images
D) diffraction of light
13) What is the purpose of adaptive optics?
A) It reduces blurring caused by atmospheric turbulence for telescopes on the ground.
B) It allows several small telescopes to work together like a single larger telescope.
C) It is a special technology that allows the Hubble Space Telescope to adapt to study many different types of astronomical objects.
D) It allows ground-based telescopes to observe ultraviolet light that normally does not penetrate the atmosphere.
14) Which of the following wavelength regions can be studied with telescopes on the ground?
A) radio, visible, and very limited portions of the infrared and ultraviolet regions
B) all light with wavelengths longer than ultraviolet wavelengths
C) all light with wavelengths shorter than infrared wavelengths
D) infrared, visible, and ultraviolet light
15) What is the purpose of interferometry?
A) It allows two or more small telescopes to achieve the angular resolution of a much larger telescope.
B) It allows two or more small telescopes to achieve a larger light-collecting area than they would have independently.
C) It is designed to prevent light pollution from interfering with astronomical observations.
D) It reduces the twinkling of stars caused by atmospheric turbulence.
16) Why is it important that the James Webb Space Telescope will be operating in the infrared?
A) It will allow us to study the highly redshifted light of distant galaxies, enabling us to observe them as they first formed in the early universe.
B) The infrared is not easily visible from Earth's surface.
C) It will allow us to be closer to the most distant galaxies, so we get better pictures.
D) It will allow us to see into other universes that are not visible from Earth's surface.
6.5 Mastering Astronomy Concept Quiz
1) Suppose you have two small photographs of the Moon. Although both look the same at small size, when you blow them up to poster size one of them still looks sharp while the other one becomes fuzzy (grainy) looking. Which of the following statements is true?
A) The one that still looks sharp at large size has better (smaller) angular resolution than the one that looks fuzzy.
B) The one that looks fuzzy at large size has better angular resolution (smaller) than the one that looks sharp.
C) Both photographs have the same angular resolution, because they were both printed at the same sizes in each case.
D) Both photographs have the same angular resolution, because they are both photographs of the same object.
2) The angular separation of two stars is 0.1 arcseconds and you photograph them with a telescope that has an angular resolution of 1 arcsecond. What will you see?
A) The two stars will appear to be touching, looking rather like a small dumbbell.
B) The stars will not show up at all in your photograph.
C) The photo will seem to show only one star rather than two.
D) You will see two distinct stars in your photograph.
3) Suppose you point your telescope at a distant object. Which of the following is not an advantage of taking a photograph of the object through the telescope as compared to just looking at the object through the telescope?
A) The photograph will have far better angular resolution than you can see with your eye.
B) By using a long exposure time, the photograph can allow you to see objects that would be too dim to see with your eye.
C) If taken with a camera with a sensitive detector such as a CCD, the photograph can capture a much larger percentage of the incoming photons than can your eye.
D) The photograph provides a more reliable record of what is seen through the telescope than can a drawing made by eye.
4) Which of the following best describes the principle advantage of CCDs over photographic film?
A) CCDs allow long exposures (e.g., minutes or hours) and film does not.
B) CCDs capture a much higher percentage of the incoming photons than film.
C) CCDs can record the colors of astronomical objects accurately while film cannot.
D) CCDs can be attached to modern telescopes more easily than can photographic film.
5) How does the light-collecting area of an 8-meter telescope compare to that of a 2-meter telescope?
A) The 8-meter telescope has 16 times the light-collecting area of the 2-meter telescope.
B) The 8-meter telescope has 4 times the light-collecting area of the 2-meter telescope.
C) The 8-meter telescope has 8 times the light-collecting area of the 2-meter telescope.
D) The answer cannot be determined from the information given in the question.
6) Which of the following best describes the development of astronomical telescopes over the past 60 years?
A) Over the 60-year period, telescopes have gradually gotten bigger and more powerful.
B) Although there have been advances in cameras and computing power, telescopes themselves have not changed much in the last 60 years.
C) The world's most powerful telescope remained the same for most of this period, but in the past 20 years many new and more powerful telescopes have been built.
D) The only major change in telescope power has occurred because of our ability to launch telescopes into space rather than operating them only from the ground.
7) Which of the following best describes why radio telescopes are generally much larger in size than telescopes designed to collect visible light?
A) Getting an image of the same angular resolution requires a much larger telescope for radio waves than for visible light.
B) Radio telescopes are designed to collect sound rather than light.
C) It is because radio telescopes are used in the daytime and visible light telescopes are used at night.
D) Objects that emit radio waves are always much larger than objects that emit visible light, and therefore require larger telescopes.
8) Which of the following studies is best suited to astronomical observations that fall into the category called timing?
A) studying how different planets differ in their surface compositions
B) studying how a star's brightness varies over a period of 3 years
C) measuring the rotation rate of a distant star
D) determining the age of the solar system
9) Which of the following is not a reason why telescopes tend to be built on mountaintops that are relatively far from cities and are in regions with dry climates?
A) The thin air on mountaintops makes the glass in telescope mirrors less susceptible to warping.
B) Being on a high mountain top means being relatively high in the atmosphere, which tends to limit turbulence.
C) Dry regions mean less rain and clouds, and mountaintops in dry regions may even allow some infrared observations.
D) Mountaintops far from cities are generally subject to less light pollution than locations nearer to cities.
10) The stars in our sky twinkle in brightness and color because of
A) turbulence in the Earth's atmosphere.
B) rapid changes in the brightnesses and colors of stars caused by changes in their spectra.
C) light pollution.
D) the bubbling and boiling of gases on the surfaces of stars.
11) Which of the following is not an advantage of the Hubble Space Telescope over ground-based telescopes?
A) It is closer to the stars.
B) Stars do not twinkle when observed from space.
C) It can observe infrared and ultraviolet light, as well as visible light.
D) It never has to close because of cloudy skies.
12) The Chandra X-Ray Observatory must operate in space because
A) X-rays are too dangerous to be allowed on the ground.
B) X-rays do not penetrate Earth's atmosphere.
C) X-ray telescopes require the use of grazing incidence mirrors.
D) It was built by NASA.
13) The James Webb Space Telescope is scheduled to launch in 2018. In what range of the electromagnetic spectrum will it operate?
14) Which of the following telescopes would benefit most from adaptive optics?
A) The Keck I Telescope on Mauna Kea.
B) The Hubble Space Telescope.
C) The Arecibo Radio Telescope in Puerto Rico.
D) The Chandra X-Ray Observatory.
15) Consider two future observatories in space. Observatory X consists of a single 50-meter telescope. Observatory Y is an interferometer consisting of five 10-meter telescopes, spread out over a region 100 meters across. Which observatory can detect dimmer stars, and which one can see more detail in its images? (Assume all else is equal, such as quality of optics, types of instruments, and so on.)
A) Observatory X can detect dimmer stars and Observatory Y reveals more detail in images.
B) Observatory Y can detect dimmer stars and Observatory X reveals more detail in images.
C) Observatory X both detects dimmer stars and reveals more detail in images.
D) Observatory Y both detects dimmer stars and reveals more detail in images.
16) Which of the following is not a major reason why astronomers would like an observatory on the far side of the Moon?
A) Telescopes on the Moon could see objects in all parts of the sky equally well, whereas telescopes on Earth can see only portions of the sky that depend on their latitude.
B) Radio astronomy would be advantageous on the Moon because human radio transmissions are less likely to cause interference, especially on the far side of the Moon.
C) It would be possible to put telescopes for ultraviolet and X-ray astronomy on the surface, unlike the case on the surface of the Earth.
D) Telescopes on the Moon could observe stars even when it is daytime on the Moon.
The Cosmic Perspective, 8e (Bennett)
Chapter 7 Our Planetary System
7.1 Multiple-Choice Questions
1) How does the Sun's mass compare with that of the planets?
A) It is a hundred times more massive than Earth.
B) It is a thousand times more massive than Earth.
C) It is a hundred times more massive than all the planets combined.
D) It is a thousand times more massive than all the planets combined.
E) It is about as massive as all the planets combined.
2) Where does nuclear fusion occur in the Sun?
A) on the surface
B) anywhere below the surface
C) in its core
D) just above the visible surface
E) all of the above
3) Which planet has the highest average surface temperature, and why?
A) Mercury, because it is closest to the Sun
B) Mercury, because of its dense carbon dioxide atmosphere
C) Venus, because of its dense carbon dioxide atmosphere
D) Mars, because of its red color
E) Jupiter, because it is so big
4) The most metal-rich terrestrial planet is
D) the Moon.
5) Which planet, other than Earth, has visible water ice on it?
C) the Moon
6) Pluto is different from the outer planets in all of the following ways except which one?
A) Its surface temperature is very cold.
B) It is made mostly of ices.
C) Its orbit is not very close to being circular.
D) It has few moons.
E) It doesn't have rings.
7) Which of the following is farthest from the Sun?
C) an asteroid in the asteroid belt
D) a comet in the Kuiper belt
E) a comet in the Oort cloud
8) Which of the following observations indicates that conditions on Mars may have been suitable for life in the past?
A) There are very large extinct volcanoes on Mars.
B) There is a very deep and long canyon that extends across Mars.
C) There is liquid water as well as a significant number of dried-up riverbeds on Mars.
D) Mars has polar caps made of "dry ice."
E) Mars has two small moons.
9) Which planet has a ring system?
E) all of the above
10) What is the primary reason why a Pluto flyby mission would be cheaper than a Pluto orbiter?
A) The flyby can use less expensive cameras than the orbiter.
B) The flyby is easier to design than the orbiter.
C) The fuel needed for an orbiter to slow down when it reaches Pluto is very expensive in and of itself.
D) The fuel needed for an orbiter to slow down when it reaches Pluto adds a lot of weight to the spacecraft.
E) The question is incorrect; in general, orbiters are cheaper than flybys.
11) What is aerobraking?
A) the technique of using a planetary atmosphere to change the orbit of a spacecraft
B) the use of a planetary atmosphere to redirect a spacecraft to another planet
C) the controlled landing of a spacecraft on a planetary surface
D) the gradual decrease of speed as a spacecraft leaves the solar system
E) the destruction of a spacecraft by the intense pressure as it descends into the atmosphere
12) Which of the following is not an advantage of spacecraft flybys over ground-based telescope observations?
A) Spacecraft can sample the gravitational field of a planet.
B) Spacecraft can view "backlit" views of planetary rings.
C) Spacecraft can measure local magnetic fields.
D) Spacecraft can monitor changes in a planet's atmosphere over long times.
E) Spacecraft can make highly detailed images of the planet and its moons.
13) Which of the following statements is not an observed pattern of motion in our solar system?
A) Most planets orbit at the same speed.
B) All planets orbit the Sun in the same direction.
C) Most planetary orbits lie nearly in the same plane.
D) Most planets rotate in the same direction in which they orbit.
E) Almost all moons orbit their planet in the same direction as the planet's rotation.
14) Which of the following is not an exception to the general patterns in the solar system?
A) the counterclockwise rotation of Venus
B) the large size of Earth's Moon
C) the rings of Saturn
D) the extreme axis tilt of Uranus
E) the retrograde rotation of Triton around Neptune
15) Which is the densest planet in the solar system?
16) The planet closest in size to Earth is
C) the Moon.
17) Which of the following is not a characteristic of the inner planets?
A) They are relatively smaller than the outer planets.
B) They all have solid, rocky surfaces.
C) Their orbits are relatively closely spaced.
D) They all have substantial atmospheres.
E) They have very few, if any, satellites.
18) Which of the following is not a characteristic of the outer planets?
A) They have very few, if any, satellites.
B) They are all large balls of gas.
C) They are primarily made of hydrogen and helium.
D) Their orbits are separated by relatively large distances.
E) They all have rings.
19) What are the main constituents of the jovian planets?
A) rocky minerals and water, as on Earth
B) hydrogen and helium
C) ammonia and methane
D) ammonia and water
E) nitrogen and methane
20) Where are most of the known asteroids found?
A) between the orbits of Mars and Jupiter
B) in the Kuiper belt
C) in the Oort cloud
D) between the orbits of the jovian planets
E) between the orbits of the terrestrial planets
21) How do asteroids differ from comets?
A) Asteroids are rocky bodies and are denser than the comets, which are made of icy material.
B) Asteroids are rocky bodies and are less dense than the comets, which are made of icy material.
C) Asteroids are made of icy material and are denser than the comets, which are more rocky.
D) Asteroids are made of icy material and are less dense than the comets, which are rockier.
E) Asteroids and comets are both made of rocky and icy material, but asteroids are smaller in size than comets.
22) Based on the frequency with which we see comets from Earth, astronomers estimate the total number of comets in the solar system to be
A) 100 million.
B) 1 billion.
C) 10 billion.
D) 100 billion.
E) 1 trillion.
23) Which of the following best describes Pluto in terms of the general characteristics of terrestrial and jovian planets?
A) size and density similar to terrestrial planets; distance and composition similar to jovian planets
B) size and solid surface similar to terrestrial planets; distance similar to jovian planets
C) size and distance similar to terrestrial planets; gaseous surface and composition similar to jovian planets
D) solid surface and density similar to terrestrial planets; temperature and composition similar to jovian planets
E) solid surface and temperature similar to terrestrial planets; distance and density similar to jovian planets
24) Astronomers have decided that, rather than being a planet, Pluto is really just a large member of
A) the asteroid belt.
B) the Kuiper belt.
C) the Oort cloud.
D) the moon system around Neptune.
E) an extrasolar planetary system.
25) Which of the following is not a pattern of motion in our solar system?
A) Planets all orbit in the same direction.
B) Planets all rotate in the same direction.
C) Planets all orbit the same direction as the Sun's spin.
D) Large planets all have many moons orbiting them.
7.2 True/False Questions
1) Oceans cover more of Earth's surface than land.
2) All four of the giant outer planets—Jupiter, Saturn, Uranus, and Neptune—have rings.
3) The jovian planets have no solid surface.
4) The planet Uranus held a special place in the mythology of the ancient Romans.
5) All planets orbit the Sun in the same direction (counterclockwise as viewed from above Earth's North Pole).
6) All the planets in the solar system have at least one moon.
7) All comets orbit the Sun in the same direction as the planets.
8) The more massive planets in the solar system tend to be less dense than the lower mass planets.
7.3 Short Answer Questions
1) What is comparative planetology, and what is its basic premise?
Answer: Comparative planetology is the approach we use to study and understand our solar system. It involves comparing the worlds of our system, including planets, moons, asteroids, and comets, to one another. Its basic premise is that the similarities and differences among the worlds can be traced to common physical processes.
2) In the 1800s, many people assumed that Venus would have tropical temperatures, but instead it is very hot. Explain why tropical temperatures would have made sense given what was known in the 1800s, and why Venus instead turns out to be very hot.
Answer: If Venus had an atmosphere similar to ours—a reasonable assumption in the 1800s—it would have tropical temperatures. But instead it has a thick carbon dioxide atmosphere that causes a very strong greenhouse effect, thus explaining its very hot surface.
3) What are some of the things that make Earth unique in the solar system?
Answer: It is the only planet with an oxygen-rich atmosphere and abundant liquid water on its surface (although there are hints that there may be liquid water on some of the moons around the jovian planets). Its surface temperature is such that water can exist in three phases: solid, liquid, and gaseous. Compared to its size, Earth also has by far the largest moon in the solar system, so much so that some astronomers consider it a double planet. Finally, Earth is the only planet we know of that harbors life.
4) Briefly summarize the differences between terrestrial and jovian planets.
Answer: Terrestrial planets are metallic or rocky in composition, close to the Sun, have higher average density, have a solid surface, are warmer at the surface, and have few if any moons. jovian planets are gaseous in composition, lower in density, have no solid surface, are farther from the Sun, and have rings and moons.
For the following questions, classify the spacecraft in one of these categories:
A. Earth orbiter B. flyby C. planetary orbiter D. lander
5) Hubble Space Telescope
6) the main part of the Galileo spacecraft (i.e., not its atmospheric probe)
8) Voyager 2
Choose from these spacecraft in the following questions.
A. Magellan B. Voyager 2 C. Apollo 11 D. Galileo E. Viking 1, 2
9) visited all four giant planets between 1979 and 1989
10) mapped most of the surface of Venus with radar observations from Venusian orbit
11) carried the first humans to the Moon on July 20, 1969
12) dropped a probe into Jupiter on December 7, 1995
13) landed on Mars in 1976
Choose from the spacecraft below for the following questions:
A. Curiosity B. New Horizon C. Cassini D. Hubble Space Telescope E. Galileo orbiter
14) used a sky crane to lower itself to the surface of Mars
15) carried a probe that landed on Titan
16) is the first spacecraft to fly by Pluto
17) has been collecting high-resolution images of Jupiter and its moons since 1995
18) is currently in orbit around Saturn
19) the only spacecraft listed that remains in Earth's orbit
20) Process of Science: In order for us to understand how the solar system got to be that way it is, we must identify the major solar system patterns that our formation theory must explain. Name 3 patterns of motion or planetary arrangement/location that our theory should be able to explain.
1. Planets orbit in the same direction.
2. Orbital direction is the same direction as the Sun's spin.
3. Most planets spin the same direction that they orbit.
4. Bigger planets are in the outer solar system.
5. Large planets have many moons.
6. Planets lie in approximately the same plane.
21) Process of Science: Pluto is no longer considered a planet. Explain the new discoveries that led to this change.
Answer: In recent years, astronomers have found numerous other bodies that orbit beyond the orbit of Neptune. These so-called Kuiper Belt objects share similar properties in being round, icy bodies and one is known to be larger than Pluto. We now recognize that Pluto is just one of a large collection of objects in the Solar System, rather the unique, individual bodies that are the planets.
22) Process of Science: Explain the varied ways in which we continue to explore the Solar System.
Answer: We learned about the nature of planets through observations of their motions with our eye and telescopes. We continue to study the planets and other Solar System objects with ground-based telescopes but also use space telescopes and spacecraft. Humans have landed on the Moon and returned with lunar samples. Robotic spacecraft have visited all the planets and provided our most detailed images of them, as well as in some cases sent probes to their surfaces or to into their atmospheres.
7.4 Mastering Astronomy Reading Quiz
1) Suppose you view the solar system from high above Earth's North Pole. Which of the following statements about planetary orbits will be true?
A) All the planets orbit counterclockwise around the Sun.
B) The inner planets orbit the Sun counterclockwise while the outer planets orbit the Sun clockwise.
C) All the planets except Uranus orbit the Sun counterclockwise; Uranus orbits in the opposite direction.
D) The inner planets orbit the Sun clockwise while the outer planets orbit the Sun counterclockwise.
2) The terrestrial planets in our solar system are
A) Mercury, Venus, Earth, and Mars.
B) Jupiter, Saturn, Uranus, and Neptune.
C) Mercury, Venus, Earth, Mars, and Pluto.
D) Jupiter, Saturn, Uranus, Neptune, Pluto, and Eris.
3) The jovian planets in our solar system are
A) Mercury, Venus, Earth, and Mars.
B) Jupiter, Saturn, Uranus, Neptune, Pluto, and Eris.
C) Jupiter, Saturn, Uranus, and Neptune.
D) Io, Europa, Ganymede, and Callisto.
4) When we say that jovian planets contain significant amounts of hydrogen compounds, we mean all the following chemicals except
B) carbon dioxide.
5) Which of the following statements about the asteroid belt is not true?
A) The combined mass of all the asteroids is roughly the same as the mass of Earth.
B) It is located between the orbits of Mars and Jupiter.
C) Asteroids in the asteroid belt orbit the Sun in the same direction that planets orbit the Sun.
D) Asteroids in the asteroid belt are made mostly of rock.
6) What is the Kuiper belt?
A) a region of the solar system that extends almost a fourth of the way to the nearest stars and contains a trillion comets with orbits going in all directions around the Sun
B) a technical name for the asteroid belt
C) the most prominent ring of Saturn that is visible in photographs
D) a region of the solar system beginning just beyond the orbit of Neptune that contains many icy bodies, including Pluto
7) What is the Oort cloud?
A) It is the spherical distribution of the trillion or so comets thought to orbit the Sun at great distances.
B) It is another name for the cloud of gas from which our solar system was born.
C) It is a great cloud of gas that resides far beyond the orbit of Pluto.
D) It is a giant storm in the atmosphere of Saturn.
8) Which of the following statements about our Sun is not true?
A) The Sun is a star.
B) The Sun's diameter is about 5 times that of Earth.
C) The Sun contains more than 99% of all the mass in our solar system.
D) The Sun is made mostly of hydrogen and helium.
9) Which of the following is not true of Mercury?
A) It has many moons.
B) At any given time, about half the planet is colder than Antarctica.
C) Its surface is heavily cratered.
D) Mercury has essentially no atmosphere.
10) Which of the following statements about Mars is not true?
A) We have landed spacecraft on its surface.
B) It is considered part of our inner solar system.
C) We could survive on Mars without spacesuits, as long as we brought oxygen in scuba tanks.
D) It has some liquid water today, but used to have large amounts of flowing water.
11) The planet in our solar system with the highest average surface temperature is