Download Question 1 The rings of Saturn are seen by Answer 1. reflected and

Question 1
. The rings of Saturn are seen by Answer
.
. 1. reflected and scattered sunlight.
.
.
. 2. reflected light from Saturn because we can see them at night.
.
.
. 3. emitted light from the molecules of the material of the rings, such as methane,
. ammonia,
.
and water vapor.
.
.
. 4. fluorescence, a glow produced by photochemistry when material is irradiated by
. solar
. UV light and/or high-speed cosmic particles.
. 1 points
Question 2
. Uranus and Neptune resemble each other in many ways. However, which of the
following statements is NOT correct ? Answer
.
. 1. Both planets appear basically featureless in photographs from Voyager 2.
.
.
. 2. Both planets have magnetic field axes tilted at large angles from their rotation axes.
.
.
. 3. Both planets (probably) have three layers: rocky core, watery mantle, and thick
. hydrogen-helium
.
atmosphere.
.
.
. 4. A system of rings circles both planets.
.
. 1 points
Question 3
. Which planet is characterized by a blue-green appearance and white, high-altitude
methane clouds surrounding dark storms? Answer
.
. 1. Uranus
.
.
. 2. Saturn
.
.
. 3. Jupiter
.
.
. 4. Neptune
.
. 1 points
Question 4
. What is the visual appearance of Neptune from space? Answer
.
. 1. blue-green and featureless
.
.
. 2. perpetually covered with yellowish, sulfur-rich clouds
.
.
. 3. blue-green with white, high-altitude clouds and dark storms
.
.
. 4. reddish belts and light zones parallel to the equator with large red spots
.
. 1 points
Question 5
. How many of the large, Galilean satellites are in synchronous rotation around Jupiter
(always turning the same face toward Jupiter)? Answer
.
. 1. inner three
.
.
.
.
. 2. inner two
.
. 3. all four
.
. 4. only Io
.
. 1 points
Question 6
. As photographed by Voyager 2, the atmosphere of Uranus shows
Answer
.
. 1. dark, whirlpool-like features and high, white clouds of methane ice crystals.
.
.
. 2. a faint haze over the north pole, but is otherwise no features.
.
.
. 3. a pinkish haze due to scattering from silicate dust particles.
.
.
. 4. light zones and dark belts circling the planet parallel to the equator.
.
. 1 points
Question 7
. The ring system around Uranus was originally discovered by what observation
technique? Answer
.
. 1. occultation of light from a star as Uranus (and the rings) passed in front of it
.
.
. 2. observation by the cameras aboard the Voyager 1 spacecraft
.
.
. 3. radar reflection from the particles in the rings
.
.
. 4. infrared observation from the IRAS spacecraft in Earth orbit
.
. 1 points
Question 8
. What is the heat source that causes the extensive volcanic activity observed on
Jupiter's satellite Io? Answer
.
. 1. “primordial” heat remaining from when Io first formed
.
.
. 2. tidal stresses from Jupiter and Io's companion moons
.
.
. 3. frictional heating by mantle convection and crustal tectonics
.
.
. 4. heat released by radioactivity in Io's core and mantle
.
. 1 points
Question 9
. What features dominate the surface of Ganymede, one of Jupiter's satellites?
Answer
.
. 1. many cracks and streaks and very few craters in an otherwise smooth, icy surface
.
.
. 2. old, dark, highly cratered polygons separated by younger, lighter, grooved terrain
.
.
. 3. volcanoes, lava lakes, and sulfur dioxide frost
.
.
. 4. craters, densely spread over the entire surface
.
. 1 points
Question 10
. The major chemical constituent of the layers of material continuously being
deposited on the surface of Io, the innermost moon of Jupiter, by “volcanic” action
is
Answer
.
. 1. water.
.
.
. 2. sulfur.
.
.
. 3. hydrogen.
.
.
. 4. silicate dust and rock.
.
Question 11
. What did we learn from the Deep Impact mission to Comet Tempel 1 in
2005?
Answer
.
. 1. The mission success or failure to collect samples will not be known until the
. spacecraft
.
returns to Earth.
.
.
. 2. The dust thrown up by the impact showed evidence of organic molecules.
.
.
. 3. Comet nuclei are highly radioactive.
.
.
. 4. A comet of this size can be completely shattered by a rather minor impact.
.
. 1 points
Question 12
. What is the specific mechanism by which the Chicxulub impact is believed to have
caused the extinction of the dinosaurs and many other species 65 million years
ago? Answer
.
. 1. The incoming asteroid contained alien biological material that destroyed susceptible
. species
.
within a few weeks of the impact.
.
.
. 2. Shock waves and tsunamis (tidal waves) killed the majority of living creatures within
. a few
. minutes of the impact.
.
.
. 3. Iridium poisoning due to fallout of meteoritic material destroyed a large fraction of
. the. creatures within several days of the impact.
.
.
. 4. Dust thrown up by the impact blotted out the Sun and disrupted the food chain over
. a period
.
of several years.
. 1 points
Question 13
. The Barringer meteorite crater is located in Answer
.
. 1. the Yucatán Peninsula, Mexico.
.
.
. 2. Arizona, U.S.A.
.
.
.
. 3. Quebec, Canada.
.
. 4. Australia.
.
. 1 points
Question 14
. The number of asteroids with diameters greater than 100 km is Answer
.
. 1. 3.
.
.
. 2. about 230.
.
.
. 3. just over 1000.
.
.
. 4. about 30.
.
. 1 points
Question 15
. How far will Comet Halley be from the Sun when it reaches its farthest point from the
Sun, or aphelion, if its sidereal period is 76 years? (Caution: This calculation needs
Kepler's law and a little care. Assume that the comet's perihelion distance from the
Sun is negligible.)
Answer
.
. 1. about 36 AU, between the orbits of Neptune and Pluto
.
.
. 2. about 9 AU, between the orbits of Jupiter and Saturn
.
.
. 3. about 18 AU, between the orbits of Saturn and Uranus
.
.
. 4. about 1324 AU, well beyond the orbit of Pluto
.
. 1 points
Question 16
. Earth's Moon subtends an angle of about 0.5° when viewed from Earth. Charon is
about 1200 km in diameter and about 18,490 km away from the surface of Pluto.
How large an angle does it subtend when viewed from Pluto?
Answer
.
. 1. about 7 times larger an angle than Earth's Moon
.
.
. 2. about 11 times larger an angle than Earth's Moon
.
.
. 3. over 100 times larger an angle than Earth's Moon
.
.
. 4. about the same size angle as Earth's Moon
.
. 1 points
Question 17
. Of the following objects in the solar system, which one has the greatest orbital
eccentricity and therefore the most elliptical orbit? Answer
.
. 1. Mercury
.
.
. 2. Mars
.
.
. 3. Earth
.
.
. 4. Pluto
.
. 1 points
Question 18
. What has been discovered in some meteorites that suggests that the formation of our
Sun and solar system might have been triggered by a supernova explosion?
Answer
.
. 1. super-pure iron, produced only in nuclear reactions
.
.
. 2. decay products of short-lived radioactive elements, which only could have been
. produced
.
in intense nuclear reactions
.
.
. 3. fusion crusts around most meteorites, indicating that they were heated intensely
. at some
.
time in their history
.
.
. 4. amino acids, which can be produced only in very specific conditions
.
. 1 points
Question 19
. In a single photograph of a comet and its tail, the only direction that one can
determine with certainty is the direction Answer
.
. 1. toward Jupiter because the gravity of this giant planet pulls the tail material toward it.
.
.
. 2. in which the comet is moving, from the trailing tail.
.
.
. 3. toward the Sun, indicated by the tail direction because gas and dust in the tail are
. attracted
.
toward the Sun by its gravity.
.
.
. 4. away from the Sun because the tail is pushed in this direction by the solar wind.
.
. 1 points
Question 20
. When compared with the diameter of Earth's Moon, the diameters of the biggest
asteroids are Answer
.
. 1. very much smaller (less than 1/10).
.
.
. 2. very much larger, by a factor of at least 5.
.
.
. 3. about the same size.
.
.
. 4. between 1/10 and 1/3 as large.
.
Question 21
. The outermost layer of a neutron star is believed to consist of Answer
.
. 1. a solid crust.
.
.
. 2. superfluid neutrons.
.
.
. 3. a molten ocean of heavy elements such as iron, neon, and magnesium.
.
.
. 4. a dense gas consisting mostly of neutrons.
.
. 1 points
Question 22
. The very strong magnetic field on a neutron star is created by Answer
.
. 1. a burst of neutrinos produced by the supernova explosion, the equivalent of a very
. large
. electrical current flowing for a short time.
.
.
.
. 2.
.
.
. 3.
.
.
. 4.
.
the collapse of the star, which significantly intensifies the original weak magnetic
field
. of the star.
differential rotation of the star, with the equator rotating faster than the poles,
similar
.
to sunspot formation.
turbulence in the electrical plasmas during the collapse of the star; the original
star. would have had no magnetic field.
. 1 points
Question 23
. A planetary nebula is a Answer
.
. 1. disk-shaped nebula of dust and gas rotating around a relatively young star in
. which
.
planets will eventually form.
.
.
. 2. gas shell, the atmosphere of a red giant star, slowly expanding away from the
. core
. of the star.
.
.
. 3. contracting spherical cloud of gas surrounding a newly formed star in which
. planets
.
are forming.
.
.
. 4. nebula caused by the supernova explosion of a massive star.
.
. 1 points
Question 24
. The Oppenheimer-Volkov limit to the amount of mass in a neutron star before
neutron degeneracy pressure is unable to withstand the force of gravity and the
neutron star is crushed out of existence into a black hole is Answer
.
. 1. 1.4 solar masses.
.
.
. 2. 20 solar masses.
.
.
. 3. about 3 solar masses.
.
.
. 4. about 100 solar masses.
.
. 1 points
Question 25
. During which phase of a low-mass star's life does helium shell fusion occur?
Answer
.
. 1. horizontal-branch
.
.
. 2. first red-giant phase
.
.
. 3. asymptotic giant branch
.
.
. 4. main-sequence
.
. 1 points
Question 26
. Cerenkov radiation that was used to detect neutrinos from supernova SN 1987A was
produced by Answer
.
. 1. neutrons ejected from nuclei by the neutrinos.
.
.
. 2. electrons and antielectrons (positrons) colliding and annihilating.
.
.
. 3. positive electrons (positrons) traveling faster than the speed of light in water.
.
.
. 4. nuclear fusion produced in the detector by neutrinos.
.
. 1 points
Question 27
. Which force induces the core to contract inward and get hotter in massive stars at
the conclusion of each episode of nuclear fusion, such as the carbon-, oxygen-,
and silicon- fusion cycles? Answer
.
. 1. electron degeneracy pressure
.
.
. 2. gravity
.
.
. 3. nuclear attractive force between nuclei and between neutrons and protons
.
.
. 4. gas pressure produced by the very high gas temperatures
.
. 1 points
Question 28
. What is a cosmic ray shower? Answer
.
. 1. pulse of gamma rays arriving at Earth from a rotating, magnetized neutron star
.
.
. 2. shower of particles produced when a cosmic ray strikes atoms in Earth's atmosphere
.
.
. 3. Another name for a meteor shower
.
.
. 4. burst of high-energy atomic nuclei arriving at Earth from interstellar space
.
. 1 points
Question 29
. The characteristics of a red supergiant star are the brightness of _____ and a
diameter of _____. Answer
.
. 1. 10,000 Suns; about Mars's orbit
.
.
. 2. about 1 million Suns; the whole solar system
.
.
. 3. the Sun; Mercury's orbit
.
.
. 4. about 10,000 Suns; 1/10 that of the Sun.
.
. 1 points
Question 30
. We have seen that electron degeneracy occurs when the carbon core of a white dwarf
becomes dense enough. We have also seen that neutron degeneracy occurs when
a neutron star becomes dense enough. Why do you suppose we do not find
“proton degeneracy” in some density range between electron and neutron
degeneracy?
Answer
.
. 1. Protons are too large and heavy to exert degeneracy pressure. This concept applies
. only
. to smaller, lighter particles like electrons.
.
.
. 2. Protons are not governed by the Pauli exclusion principle, as are electrons and neutrons.
.
.
. 3. The pressure at which the electron degeneracy is overcome (so that the core collapses)
. is also
.
sufficient to combine electrons and protons to form neutrons. Thus, most
. protons disappear when the electron degeneracy ends.
.
.
. 4. These degeneracies can occur only for neutral particles, and protons carry an electric
. charge.
.
Question 31
. According to Einstein's general theory of relativity, a clock that ticks at a regular rate
far from a source of gravity will appear to tick Answer
.
. 1. at the same rate, wherever it is placed in a gravitational field.
.
.
. 2. at the same rate in a gravitational field if it is an atomic clock but at a slower rate
. if it. is a mechanical clock.
.
.
. 3. faster the closer it comes to the source of gravity.
.
.
. 4. slower the closer it comes to the source of gravity.
.
. 1 points
Question 32
. What is the observed distribution of the shorter-living gamma-ray bursters in the
sky? Answer
.
. 1. clumpy, approximately coinciding with large clusters of galaxies such as the Coma
. cluster
.
.
.
. 2. clumpy but not coinciding with any known galaxy clusters, indicating an origin in a
. new
. kind of astronomical object
.
.
. 3. concentrated primarily along the plane of the Milky Way, indicating an origin in the
. Galaxy
.
.
.
. 4. uniform over the entire sky, indicating an origin at “cosmological” distances
.
. 1 points
Question 33
. Which of the following properties can never be known about a black hole? Answer
.
. 1. net electric charge
.
.
. 2. total amount of matter (the mass) inside it
.
.
. 3. angular momentum (spin)
.
.
. 4. type of material inside it
.
. 1 points
Question 34
. Two spaceships are traveling past Earth at 90% of the speed of light in opposite
directions (i.e., they are approaching each other). One turns on a searchlight,
which is seen by scientists aboard the other. What speed do the scientists
measure for this light (c = speed of light in a vacuum)?
Answer
.
. 1. 1.9 c (equal to c + 0.9 c)
.
.
. 2. c
.
.
. 3. 1.8 c (equal to 2 × 0.9 c).
.
.
. 4. 0.9 c
.
. 1 points
Question 35
. Gamma-ray bursters are great distances from Earth, yet Earth receives tremendous
amounts of energy from them. Explain. Answer
.
. 1. Gamma-ray bursters are supermassive stars, equivalent to 100,000 ordinary
. supernovae.
.
.
.
. 2. The energy is released along jets rather than uniformly in all directions. If
. Earth
. is in the path of one of these jets, we see a gamma-ray burster.
.
.
. 3. The gamma radiation from a burster is released in all directions, but then it
. is focused
.
in the direction of the Earth by gravitational lensing.
.
.
. 4. A gamma-ray burster represents the explosion of an entire galaxy.
.
. 1 points
Question 36
. In a binary star system, one component is found to have about 3 solar masses, the
other about 7 solar masses. The 3-solar-mass star is visible from Earth, but the 7solar-mass star is not. Theoretical considerations tell us that the 7-solar-mass star
must be a Answer
.
. 1. cool planetary object.
.
.
. 2. white dwarf.
.
.
. 3. neutron star.
.
.
. 4. black hole.
.
. 1 points
Question 37
. According to Newton's law of gravity, why does Earth orbit the Sun? Answer
.
. 1. Earth and the Sun are continually exchanging photons of light in a way that holds
. Earth
. in orbit.
.
.
. 2. The Sun exerts a gravitational force on Earth across empty space.
.
.
.
. 3. Matter contains quarks, and Earth and the Sun attract each other with the “color force”
. between
.
their quarks.
.
. 4. Space around the Sun is curved.
.
. 1 points
Question 38
. In the context of black holes, the word ergosphere names the
Answer
.
. 1. entire universe outside the black hole.
.
.
. 2. entire region inside the event horizon.
.
.
. 3. region occupied by the accretion disk where matter from a companion star collects
. around
.
a black hole.
.
.
. 4. region just outside the event horizon of a rotating black hole where it is impossible
. for .anything to remain at rest.
. 1 points
Question 39
. In general, how many fundamentally different types of black holes are expected to
exist? Answer
.
. 1. two—those that rotate and those that do not rotate
.
.
. 2. only one—all properties but mass are destroyed when a black hole is created
.
.
. 3. two—those that have electric charge and those that have no electric charge
.
.
. 4. three—atomic-mass black holes, stellar-mass black holes, and supermassive black holes
.
. 1 points
Question 40
. According to general relativity, why does Earth orbit the Sun? Answer
.
. 1. The Sun exerts a gravitational force on Earth across empty space.
.
.
. 2. Matter contains quarks, and Earth and the Sun attract each other with the “color force”
. between
.
their quarks.
.
.
. 3. Earth and the Sun are continually exchanging photons of light in a way that holds Earth
. in orbit.
.
.
.
. 4. Space around the Sun is curved, and Earth follows a geodesic in this curved space.
.
Question 41
. Suppose we were able to detect radio signals from an intelligent civilization in the
Coma cluster of galaxies. If we were to send a message to this civilization, how
long would it take to get a reply? Answer
.
. 1. 150 million years
.
.
. 2. 75 million years
.
.
.
. 3. 300 million years
.
. 4. 600 million years
.
. 1 points
Question 42
. A rich, regular cluster of galaxies differs from a rich, irregular cluster in that
Answer
.
. 1. it contains fewer galaxies than does an irregular cluster.
.
.
. 2. it has fewer spirals and more ellipticals and S0 galaxies than an irregular cluster.
.
.
. 3. it lacks the giant elliptical galaxies often found in irregular clusters.
.
.
. 4. its galaxies are distributed in a regular, highly flattened system (like a disk).
.
. 1 points
Question 43
. Why is the Milky Way Galaxy different from most spiral galaxies? Answer
.
. 1. The Milky Way has only two spiral arms, whereas most galaxies have at least four.
.
.
. 2. The Milky Way has only three spiral arms, whereas most spiral galaxies have at least four.
.
.
. 3. The spiral arms of the Milky Way are far more tightly wound than those in most galaxies.
.
.
. 4. The Milky Way has at least four spiral arms, whereas most galaxies have only two.
.
. 1 points
Question 44
. According to the Hubble classification scheme, an E4 galaxy has a(n) Answer
.
. 1. elliptical shape (a flattened circle) with a smooth light distribution.
.
.
. 2. round or spherical shape with a smooth light distribution and no disk or central bulge.
.
.
. 3. disk and central bulge with a smooth light distribution and no spiral arms.
.
.
. 4. irregular shape.
.
. 1 points
Question 45
. One piece of evidence for the existence of dark matter is the Answer
.
. 1. discrepancy between observed mass and the required gravitational binding in rich
. clusters
.
of galaxies.
.
.
. 2. absence of interstellar materials (gas and dust) from elliptical galaxies.
.
.
. 3. scarcity of dwarf ellipticals in the Local Group of galaxies.
.
.
. 4. low count of neutrinos emitted from the center of the Sun.
.
. 1 points
Question46
. Collisions between galaxies Answer
.
. 1. are relatively fleeting because galaxies move so rapidly and thus last only a few
. million
.
years.
.
.
. 2. can last hundreds of millions of years.
.
.
. 3. do not occur because the distances between galaxies are so vast.
.
.
. 4. have little long-term effect on the galaxies involved because gravity is a relatively
. weak
. force and the distances over which it must act between galaxies are so great.
. 1 points
Question 47
. In which of the following types of galaxies is star formation no longer occurring?
Answer
.
. 1. spiral galaxies
.
.
. 2. barred spiral galaxies
.
.
. 3. irregular galaxies
.
.
. 4. elliptical galaxies
.
. 1 points
Question 48
. Spiral galaxies are classified in terms of increasing tightness of their spiral arms as
types Sa, Sb, and Sc. However, many spiral galaxies are aligned edge-on to Earth
and their spiral arms cannot be seen. Which other parameter that is directly related
to spiral arm tightness can be easily seen edge-on and can therefore be used to
provide this classification? Answer
.
. 1. overall spectral color
.
.
. 2. size of the nuclear bulge
.
.
. 3. overall diameter of the galaxy
.
.
. 4. overall intrinsic brightness of the galaxy, or its absolute magnitude
.
. 1 points
Question 49
. In our universe, we can consider four different regimes of space in which distances
between objects might be changing as a result of the general expansion of the
universe: (1) distances between different parts of Earth, (2) distances between
planets in our solar system, (3) distances between stars in the Milky Way Galaxy,
and (4) distances between clusters of galaxies. In which of these regimes are the
distances changing because of the universal expansion? Answer
.
. 1. 4 only
.
.
. 2. 4, 3, and 2
.
.
. 3. 4 and 3
.
.
. 4. 4, 3, 2, and
. 1
. 1 points
Question 50
. An astronomer studying a distant galaxy finds that its recessional velocity is 14,000
km/s. What is the distance to the galaxy? Assume Hubble's constant to be 70 km/s
per Mpc. Answer
.
. 1. 980,000
. Mpc
.
. 2. 200 Mpc
.
.
. 3. 98 Mpc
.
.
. 4. 2000 Mpc
.