Question 1
1.
What is the explanation for the bright cells of photospheric gases that make up the cellular granulation pattern seen on
the visible surface of the Sun?
Answer
1. The cells are the base of a circulation pattern that extends from the photosphere to the outer corona.
2. The cells are the tops of blobs of hot gas that have risen from the Sun's convective zone.
3. Each cell is a region of strong magnetic field, which compresses and heats the gas within it.
4. The cells are regions of nuclear energy generation in the Sun's photosphere.
1 points
Question 2
1.
The difference between an umbral eclipse and a penumbral eclipse is
Answer
1. entirely dependent on your viewing position on Earth.
2. the distance of the Moon above or below the ecliptic.
3. whether the Moon is farther from the Sun than Earth is or whether it is closer to the Sun than Earth is.
4. whether Earth's rotation axis is tilted toward or away from the Moon during the eclipse.
1 points
Question 3
1.
The temperature of the corona of the Sun is
Answer
1. about twice as hot as the photosphere, 12,000 K.
2. very cool because it is the farthest part of the Sun from the heat source.
3. very
hot, about 106 K.
4. about the same as that of the photosphere, 5800 K.
1 points
Question 4
1.
Spicules on the solar surface are
Answer
1. streams of solar coronal material, usually seen only during a total solar eclipse.
2. intense eruptions from sunspot groups and active regions, associated with solar flares.
3. jets of gas surging out of the photosphere of the Sun into the chromosphere, usually at supergranule boundaries.
4. curtainlike structures hanging over sunspot regions.
1 points
Question 5
1.
One distinctive feature that is visible on the “surface” of Jupiter through a telescope from
the Earth is
Answer
1. Olympus Mons.
2. the northern auroral oval.
3. the Cassini Division.
4. the Great Red Spot.
1 points
Question 6
1.
Intense magnetic fields have been found to exist in sunspots by the observation of what specific physical effect?
Answer
1. observation of ionized atoms in the region of the sunspots
2. measurement of the relative strengths of spectral absorption lines of gases in the sunspot
3. Zeeman effect, the splitting of spectral absorption lines
4. Doppler shift of light from sunspots
1 points
Question 7
1.
The ancient Greek thinker whose model of the universe came to dominate the medieval world was
Answer
1. Zorba.
2. Archimedes.
3. Alexander.
4. Ptolemy.
1 points
Question 8
1.
An object is in an orbit caused by its gravitational attraction to the Sun. This orbit
Answer
1. must be a parabola.
2. must be an ellipse.
3. must be a hyperbola.
4. might be an ellipse, a parabola, or a hyperbola.
1 points
Question 9
1.
Approximately what fraction of its main-sequence lifetime has the Sun completed at the
present time (see Table 12-2, Comins and Kaufmann, Discovering the Universe, 8th ed.)?
Answer
1. about 3/4
2. less than 10%
3. about 1/2
4. about 1/4
1 points
Question 10
1.
At approximately what time does the new Moon rise?
Answer
1. close to sunrise
2. sunset
3. midnight
4. midday
1 points
Question 11
1.
One prominent feature recently identified within many energetic close binary star systems as a result of their mutual
interaction and mass exchange is
Answer
1. a cool dust cloud surrounding the whole star system, hiding it from visible view.
2. planetary formation between the stars, emitting IR radiation from molecular constituents and dust.
3. the beginnings of spiral arms, showing the possible origin of spiral galaxies.
4. two oppositely directed high-speed jets of matter leaving the system.
1 points
Question 12
1.
The temperature of the Sun throughout its radius and including its atmosphere
Answer
1. increases and decreases several times between the center and the surface, then decreases through the
atmosphere.
2. is almost constant from the center to the surface but falls abruptly above the visible surface.
smoothly outward from the center, gradually merging at the “top” of the
atmosphere into the cold of the interplanetary medium.
3. decreases
4. decreases outward from the center but then increases again in the atmosphere.
1 points
Question 13
1.
The four giant moons of Jupiter were discovered by
Answer
1. Newton, in seventeenth-century England.
2. Galileo, in seventeenth-century Italy.
3. the
Pioneer spacecraft, the first spacecraft to visit Jupiter.
4. Ptolemy, in ancient Greece.
1 points
Question 14
1.
Which of the following sentences correctly states the significance of Galileo's observation that Jupiter has satellites
(moons)?
Answer
1. The observation showed that Jupiter must be four times the size of the Earth (because Jupiter has four moons
and the Earth has one).
2. The observation showed that bodies can orbit an object other than the Earth.
3. The observation showed that Jupiter must orbit the Sun, not the Earth.
4. The observation was interesting but had no other particular significance.
1 points
Question 15
1.
A total lunar eclipse can last more than an hour and a half, but a total solar eclipse never lasts more than 7 1/2 minutes.
Why the difference?
Answer
1. Both Earth and the Moon move clockwise in their orbits, as seen from the north. Thus during a solar eclipse
Earth and Moon are moving in opposite directions, and during a lunar eclipse they are moving in the same
direction.
2. Earth's shadow at the Moon's distance is much larger than the Moon's shadow at Earth's distance. As Earth
rotates, this narrow lunar shadow sweeps quickly over any given spot.
3. A total solar eclipse always occurs when Earth is at perihelion; it is moving fastest at that time.
4. A total solar eclipse always occurs when the Moon is at perigee; it is moving fastest at that time.
1 points
Question 16
1.
The temperature in the atmosphere of Venus (see Figure 7-11, Comins and
Kaufmann, Discovering the Universe, 8th ed.)
Answer
1. increases smoothly with increasing altitude.
2. is almost constant with altitude.
3. has a complicated structure reaching several maxima and minima at various altitudes.
4. decreases smoothly with increasing altitude.
1 points
Question 17
1.
The 21-cm line is one of the most important wavelengths in radio astronomy. It is produced mainly in
Answer
1. hot O and B stars.
2. ionized hydrogen.
3. emission nebulae.
4. neutral hydrogen.
1 points
Question 18
1.
When we look out into the plane of the Milky Way Galaxy, how far can we see?
Answer
1. about 100,000 ly
2. infinitely far
3. less than 1000 ly
4. about 10,000 ly
1 points
Question 19
1.
The “helium flash” occurs in a 2-solar-mass star when
Answer
1. the core temperature becomes sufficiently high for helium fusion for the first time.
2. hydrogen fusion ceases abruptly, leaving only the fusion of helium to generate energy.
3. the core heats up from helium fusion and the gas does not expand to cool down and stabilize the temperature
because the gas properties are controlled by degenerate electrons.
4. convection within the star carries helium to the surface, where it shows its own characteristic spectrum for the
first time.
1 points
Question 20
1.
An atom is now known to consist of a
Answer
1. positively charged crystal structure with electrons moving within it.
2. small, positively charged black hole with electrons held in orbits around it by intense gravitational forces.
3. small, massive, electrically charged core surrounded by electrons.
4. uniform distribution of positively charged matter with electrons embedded in it.
1 points
Question 21
1.
Newton stated that a constant force, continuously applied to a body in space, will give it a
Answer
1. constant velocity.
2. headache.
3. constant acceleration.
4. change of position from one state of rest to another state of rest.
1 points
Question 22
1.
The nearest quasar is
Answer
1. among the nearby superclusters of galaxies.
2. in the Milky Way Galaxy.
3. in the Local Group of galaxies.
4. barely visible at the remote edge of the observable universe.
1 points
Question 23
1.
How is chromatic aberration most often corrected in a modern refracting telescope?
Answer
1. by grinding the lens surfaces into a parabolic shape
2. by using a prism to recombine the colors into white light
3. by painting the inside of the telescope jet black to minimize reflections
4. by using a combination of two lenses made from different types of glass
1 points
Question 24
1.
What is the name for a theory that describes the overall structure of the universe in which the Earth is located?
Answer
1. cosmology
2. astronomy
3. field theory
4. astrology
1 points
Question 25
1.
Where on the Sun do solar flares occur?
Answer
1. only within sunspot groups
2. only in a narrow band along the solar equator
3. only at the polar regions
4. only in coronal holes
1 points
Question 26
1.
What experimental evidence do we have for the direct transformation of energy into matter?
Answer
1. blueshift of light because of the motion of its source
2. relativistic increase in mass of an object when it is moving very rapidly
3. Conversion of gamma-ray photons into electrons and antielectrons (i.e., positrons)
4. increase in the force upon a body when it is accelerated upward (e.g., in an elevator)
1 points
Question 27
1.
When did the universe cool to a temperature of 3 K?
Answer
1. 1 second after the start of the Big Bang, when pair production ceased
2. 3 minutes after the start of the Big Bang, when primordial nuclear reactions ceased
3. 500,000 years after the Big Bang, when the universe became transparent to radiation
4. very recently
1 points
Question 28
1.
In which order (from earliest to latest) did the following people make their major contributions to astronomy?
Answer
1. Kepler, Copernicus, Brahe, Newton
2. Brahe, Copernicus, Newton, Kepler
3. Copernicus, Brahe, Kepler, Newton
4. Copernicus, Kepler, Brahe, Newton
1 points
Question 29
1.
The most noticeably elliptical planetary orbit is the orbit of
Answer
1. Mars.
2. Earth.
3. Uranus.
4. Mercury.
1 points
Question 30
1.
Which of the following features appears in the spectrum of the solar corona and indicates very high gas temperatures?
Answer
1. bright
emission from the hydrogen Balmer line, Hα, at the red end of the spectrum
2. intense continuous emission in the infrared part of the spectrum
3. ntense emission lines from highly ionized atoms, such as iron
4. dark absorption lines from hydrogen, calcium, and iron on a continuous bright spectrum
1 points
Question 31
1.
The planet with the greatest mean density is
Answer
1. Earth.
2. Neptune.
3. Mercury.
4. Jupiter.
1 points
Question 32
1.
What was the most important difference between the development of Isaac Newton's theory of planetary motion and
that of Johannes Kepler?
Answer
1. Newton lived in a freer political climate, whereas Kepler risked house arrest if his theory opposed the Bible or
Aristotle.
2. Newton developed his theory from basic physical assumptions, whereas Kepler simply adjusted his theory to fit
the data.
3. Newton based his theory on accurate telescopic observations, whereas Kepler used observations made by eye.
4. Newton lived in England, which is famous for clear skies, whereas Kepler lived on the continent, which is
notorious for bad weather.
1 points
Question 33
1.
The core (inner and outer) of Earth extends over what fraction of its radius?
Answer
1. almost 80%
2.
about
3.
roughly
4. less than 10%
1 points
Question 34
1.
The surprising observational fact about quasars is that they appear to
Answer
1. be associated with ancient supernova explosions.
2. produce the energy output of greater than 100 galaxies in a volume similar to that of our planetary system.
3. be the largest known structures in the universe, although they produce only modest amounts of energy.
4. be moving rapidly toward us while emitting large amounts of energy.
1 points
Question 35
1.
Of the following objects in the solar system, which one has the greatest orbital inclination (orbit at the greatest angle to
that of Earth)?
Answer
1. Pluto
2. Mercury
3. Jupiter
4. Mars
1 points
Question 36
1.
The space between stars is known to contain
Answer
1. large quantities of dust that absorb and scatter light but no gas, either atomic or molecular.
2. variable amounts of gas but no dust, which forms only in planetary systems near stars.
3. gas, both atomic and molecular, and dust.
4. a perfect vacuum.
1 points
Question 37
1.
What observations of the Martian surface led Lowell to the conclusion that intelligent life-forms existed on Mars?
Answer
1. lakes and rivers of water flowing from polar icecaps and detected by strong specular reflection of sunlight
2. melting icecaps, a network of linear features that look like canals, and varying dark surface marking assumed to
be vegetation
3. geometrical structures and patterns that are apparently the remains of buildings and cities
4. sculpted mountains in the shape of humanoid heads, obviously carved to announce the presence of intelligent
life to distant observers
1 points
Question 38
1.
Main-sequence stars apparently are not larger than a few hundred solar masses. The reason stars of larger mass do not
exist is that
Answer
1. the thermonuclear reactions in such stars proceed so rapidly that the stars explode.
2. their temperature becomes so high that they are disrupted by the pressure of radiation inside them.
3. interstellar clouds of greater mass break up to become binary or multiple-star systems, not single stars.
4. such stars contract directly to become planetlike objects.
1 points
Question 39
1.
In the simplified version of Kepler's third law, P2 = a3, the units of the orbital
period P and the semimajor axis of the ellipse amust be, respectively,
Answer
1. seconds and meters.
2. years and meters.
3. years and light-years.
4. years and astronomical units.
1 points
Question 40
1.
The source of the water found in the form of ice near Mercury's north and south poles is
Answer
1. a former global ocean, now almost entirely evaporated and lost to space.
2. rainfall early in Mercury's history, when the planet had a dense atmosphere.
3. unknown at the present time.
4. comet impacts.
1 points
Question 41
1.
What is the typical temperature inside the dense core of a giant molecular cloud that is collapsing to form a star?
Answer
1. 1000 K
2. 100 K
3. 10 K
4. less than 1 K
1 points
Question 42
1.
Earth's thermosphere is the
Answer
1. intermediate
atmospheric layer in which ultraviolet light from the Sun is absorbed
by ozone (O3) molecules.
2. outermost atmospheric layer in which ultraviolet light from the Sun ionizes atoms.
3. region of the magnetosphere in which trapped high-energy charged particles spiral along magnetic field lines.
4. layer of molten iron and nickel below the mantle.
1 points
Question 43
1.
Why are carbonaceous chondrites thought to be original material that formed in the early solar nebula?
Answer
1. The minerals of a carbonaceous chondrite contain up to 20% water, which would have evaporated away if the
chondrite had been strongly heated.
2. Carbonaceous chondrites show a Widmanstätten pattern, which indicates slow
condensation from gaseous material.
3. Carbonaceous chondrites consist mostly of carbon, which was the dominant substance condensing in the outer
solar nebula.
4. Carbonaceous chondrites consist almost entirely of ice, which would have sublimed away by now if this were
not the first time the chondrite was passing close to the Sun.
1 points
Question 44
1.
How is water ice able to remain on the surface of Mercury, despite the planet's close proximity to the Sun?
Answer
1. The water ice is continuously replenished by fresh impacts from comets.
2. The water ice exists as permafrost below the thermally insulating surface and is exposed only by occasional
impacts.
3. The water ice is permanently shielded from the Sun by crater walls at the north and south poles.
4. The water ice is continuously replenished by condensation of water vapor from volcanoes.
1 points
Question 45
1.
What property is shared by the Earth and Europa, one of Jupiter's large moons?
Answer
1. The Earth and Europa both have warm oceans of water.
2. The Earth and Europa have both been shown to harbor intelligent life in their oceans.
3. The Earth and Europa both have thick atmospheres of nitrogen and oxygen.
4. The Earth and Europa are about the same physical size.
1 points
Question 46
1.
The distance to the bright quasar 3C 273 is estimated to be
Answer
1. just beyond the Milky Way.
2. 2 billion ly.
3. 3 million ly.
4. 20,000 ly.
1 points
Question 47
1.
Spacecraft measurements indicate that the surface of Venus is dominated by
Answer
1. basalt, a volcanic rock formed when lava solidifies on the surface.
2. schist, a metamorphic rock formed by the deformation of other rocks by pressure and heat.
3. sandstone, a sedimentary rock formed on Venus by sand grains deposited by wind.
4. granite, a plutonic rock formed when lava solidifies deep below the surface.
1 points
Question 48
1.
In what crucial way is the atmosphere of Earth very different from the atmospheres of Venus and Mars?
Answer
1. Earth's atmospheric temperature is relatively cool, whereas both Venus and Mars have very high atmospheric
temperatures.
2. Carbon dioxide (CO2) gas is the dominant component in the atmospheres of Venus
and Mars, but it is only a minor constituent in Earth's atmosphere.
3. Hydrogen (H) gas makes up a large fraction of the atmospheres of both Venus and Mars, but it is absent from
Earth's atmosphere.
4. Methane (CH4) gas is present in large quantities on Venus and Mars, but it is only a
trace gas on Earth.
1 points
Question 49
1.
What is helioseismology?
Answer
1. study of vibrations in the Sun's interior
2. study of the Sun's tidal effects in causing earthquakes
3. detailed study of the shape of the Sun
4. study of the Sun's response to collisions with grazing comets
1 points
Question 50
1.
105/105 =
Answer
1. 0
2. 1
3. 10
4. 1012
1 points
Question 51
1.
The heat energy that powers tectonic activity on the surface of Earth originates deep in Earth's core. How does this
energy move from the core to the surface?
Answer
1. steady flow of hot magna from Earth's core through cracks in the mantle to the lithosphere
2. conduction throughout the entire mantle
3. conduction through the solid lower mantle and convection in the upper mantle (asthenosphere)
4. convection throughout the entire mantle
1 points
Question 52
1.
What was the declination of the Sun on March 21 this year?
Answer
1. 180°
2. It
would have no unique value but could be any angle between +23.5° and –23.5°.
3. 23.5°
4. 0°
1 points
Question 53
1.
The surface of the Sun near its edge appears dimmer and cooler than at the center of the disk when viewed in visible
light because we see
Answer
1. light from the edge that has had to pass through more of the absorbing chromosphere and corona and is thereby
reduced in intensity.
2. less deeply into the Sun near the edge than at disk center and temperature increases with depth.
3. less deeply into the Sun near the edge than at disk center and temperature decreases with depth.
4. deeper into the Sun near the edge than at disk center and temperature increases with depth.
1 points
Question 54
1.
A particular star has an absolute magnitude of +12 and a spectral class of A5. Using
Figures 11-7 and 11-10 of Comins and Kaufmann, Discovering the Universe, 8th ed.,
how would this star be classified?
Answer
1. A5 III
2. A5 I
3. A-type white dwarf
4. A5 V
1 points
Question 55
1.
An astronomer studying a galaxy finds that its spectrum shows only old, low-mass, Population II stars, and photographs
of the galaxy show little or no interstellar gas or dust. What kind of galaxy is this astronomer studying?
Answer
1. spiral galaxy
2. An irregular galaxy
3. barred spiral galaxy
4. elliptical galaxy
1 points
Question 56
1.
The Oort cloud is
Answer
1. a random distribution of short-period comets extending from inside the orbit of Jupiter to approximately the
orbit of Neptune.
2. a flat or donut-shaped distribution of distant comets around the Sun, extending out about 500 AU.
3. a spherical distribution of distant comets around the Sun, extending out about 50,000 AU.
4. another name for the asteroid belt.
1 points
Question 57
1.
The light from a distant cloud of gas and dust looks distinctly red to the naked eye. When a spectrum is taken it is
found that many wavelengths which would normally be expected to be in the middle of the spectrum have been shifted
into the long wavelength end of the spectrum. Thus the red color in this situation is due to
Answer
1. interstellar reddening, the Balmer spectrum of hydrogen, or the Doppler effect.
2. the Balmer spectrum of hydrogen.
3. the Doppler effect.
4. interstellar reddening.
1 points
Question 58
1.
What is the name of a small jet of rising gas in the chromosphere of the Sun?
Answer
1. spicule
2. flare
3. granule
4. prominence
1 points
Question 59
1.
Where are bright, young O and B stars most likely to be found in the Milky Way Galaxy?
Answer
1. between spiral arms, where there is less absorbing material
2. inside spiral arms
3. in globular clusters
4. in
the outermost regions of the disk, where much of the “dark matter” is located
1 points
Question 60
1.
A star rises at 8 P.M., moves across the sky (crossing high overhead), and then sets at
Answer
1. noon.
2. 8 A.M.
3. 2 A.M.
4. midnight.
1 points
Question 61
1.
What is the solar wind?
Answer
1. storm of waves and vortices on the Sun's surface generated by a solar flare
2. material from the corona, accelerated out into space
3. constant flux of photons from the Sun's visible surface
4. circulation of gases in the chromosphere, between the equator and the poles of the Sun
1 points
Question 62
1.
On the basis of the recent interpretation of geological evidence, the impact of a 10-km-diameter asteroid on the surface
of Earth would be very likely to
Answer
1. create significant damage near the impact site but have relatively little lasting worldwide effect.
2. completely destroy life on Earth.
3. shatter Earth into fragments.
4. disrupt the global ecology and cause the extinction of a large percentage of all species living on Earth.
1 points
Question 63
1.
After the material in the core of a massive star has been converted to iron by thermonuclear reactions, further energy
can be released to heat the core only by
Answer
1. gravitational contraction.
2. the absorption of neutrinos.
3. thermonuclear fusion of iron into heavier elements.
4. nuclear fission, or splitting of nuclei.
1 points
Question 64
1.
Who was the first astronomer to use a telescope for viewing the sky?
Answer
1. Newton
2. Galileo
3. Ptolemy
4. Brahe
1 points
Question 65
1.
What is the only way to measure the mass of a star accurately?
Answer
1. It is not possible to measure the mass of a star.
2. Measure its distance using trigonometric parallax and its brightness using photometry.
3. Measure its gravitational effect on another object.
4. Measure its spectral type and luminosity class, then use the H-R diagram.
1 points
Question 66
1.
Which of the following phenomena is NOT seen on Jupiter's satellite Io?
Answer
1. volcanic plumes
2. impact craters
3. lava flows
4. sulfur dioxide frost
1 points
Question 67
1.
What appears to be the “impact history” of cratering on the Moon?
Answer
1. early period of heavy bombardment, then very light bombardment to the present
2. heaviest bombardment when the Moon first formed, gradually decreasing to light bombardment today
3. short periods of heavy bombardment alternating with long periods of light bombardment throughout the Moon's
life
4. more or less constant bombardment from the earliest times to the present
1 points
Question 68
1.
Using the distance to the Coma cluster of galaxies and the Hubble relation (using an
intermediate value of the Hubble constant H0 equal to 80 km/s per million parsecs; see
Figure 16-21, Comins and Kaufmann, Discovering the Universe, 8th ed.), what would be
the approximate wavelength shift of the Balmer Hα spectral line at 656.3 nm emitted by a
galaxy in the cluster because of the general expansion of the universe? (See also
Astronomer's Toolbox 16-1 of Comins and Kaufmann,Discovering the Universe, 8th ed.)
Answer
1. 1.61 nm
2. 1.61
× 106 nm
3. 16.1 nm
4. 161.0 nm
1 points
Question 69
1.
What proportion of visible stars in our nighttime sky are members of multiple-star systems, such as binary stars?
Answer
1. close to 100%
2. only about 1/4, or 25%
3. less than 1%
4. 2/3, or almost 70%
1 points
Question 70
1.
In the southern hemisphere, day and night are of equal duration on about
Answer
1. January 1, by definition.
2. June 21.
3. March 21.
4. December 21.
1 points
Question 71
1.
What is the important difference between modern neutrino detectors and the chlorine-argon detection system of
previous decades?
Answer
1. The new detectors are able to detect all three neutrino types, not just those originally emitted from the Sun.
2. The new detectors are smaller and thus can be built more cheaply.
3. The new detectors can be tuned to detect neutrinos of any energy.
4. The new detectors are in orbit above our atmosphere, thus avoiding the loss of neutrinos absorbed in Earth's
atmosphere.
1 points
Question 72
1.
In the 1860s, James Clerk Maxwell carried out important investigations on the nature of light when he
Answer
1. proved mathematically that light could be described by oscillating electric and magnetic fields.
2. showed that a prism through which light passed added a spectrum of colors to the light.
3. demonstrated the wave nature of light by passing light through two slits and obtaining a pattern of bright and
dark bands on a screen that he correctly interpreted as interference between the two light beams.
4. demonstrated that white light was made up of colors that could be split by a prism and that these colors were not
produced by the glass through which the light passed.
1 points
Question 73
1.
The amount of light reflected by a planet or other object is its
Answer
1. apparent magnitude.
2. albedo.
3. emissivity.
4. color index.
1 points
Question 74
1.
Sometimes high tides are lower than at other times. What name is given to the lowest high tides?
Answer
1. pep tides
2. neap tides
3. spring tides
4. rip tides
1 points
Question 75
1.
What were the dominant gases in Earth's earliest atmosphere after it first formed?
Answer
1. carbon dioxide and nitrogen
2. hydrogen and helium
3. nitrogen and oxygen
4. methane and ammonia
1 points
Question 76
1.
Which wavelength region of the electromagnetic spectrum is taken up by visible light?
Answer
1. 400 nm to 700 nm
2. 100 nm to 400 nm
3. 4000 nm to 7000 nm
4. 1200 nm to 1500 nm
1 points
Question 77
1.
One or more natural satellites (moons) do NOT orbit which planets?
Answer
1. Mercury and Mars
2. Mercury, Venus, and Mars
3. Mars and Venus
4. Mercury and Venus
1 points
Question 78
1.
If we characterize the age of a surface by the age of the oldest feature that has been dated there, then the ages of the
following surfaces are, from youngest to oldest,
Answer
1. Venus, the Earth, and the Moon.
2. the Earth, the Moon, and Venus.
3. Venus, the Moon, and the Earth.
4. the Earth, Venus, and the Moon.
1 points
Question 79
1.
The average distance from the Earth to the Sun, 149,600,000 km, can be written in shorthand notation as
Answer
1. 1.496
× 109 km.
2. 1.496 × 108 km.
3. 1.496 × 106 km.
4. 1.496 × 107 km.
1 points
Question 80
1.
The light intensity from a particular star remains essentially constant except for short and regular decreases and
increases by a fixed amount. What is the explanation for this phenomenon?
Answer
1. A variable star is pulsating in size, temperature, and intensity.
2. A massive, dark planet is periodically passing in front of the star's visible surface.
3. Shells of absorbing gas and dust are being periodically ejected from the star's surface and are subsequently
dispersing into space.
4. One star is regularly eclipsing its companion as they move in mutual orbits whose plane is close to the line of
sight.
1 points
Question 81
1.
Over an interval of 6 months, the tilt of the Earth's spin axis with respect to the background stars will change by
Answer
1. 47°.
2. 180°.
3. 23.5°.
4. 0°.
1 points
Question 82
1.
One of the first people to look for radio signals from extraterrestrial civilizations was
Answer
1. Frank Drake.
2. Martin Schwarzschild.
3. Jocelyn Bell.
4. Arno Penzias.
1 points
Question 83
1.
Accretion of matter in an interstellar cloud leads to
Answer
1. explosion of this matter when it is attracted to and falls onto the surfaces of stars.
2. the formation of molecules from atomic gases.
3. a protostar.
4. a supernova explosion since accretion is a nuclear process.
1 points
Question 84
1.
The structure of Ganymede, a Galilean satellite of Jupiter, is thought to be
Answer
1. an iron core, a rocky mantle, and a liquid ocean with a dirty ice surface.
2. mostly or entirely rock, with no firm evidence of an iron core, and active volcanoes on its surface.
3. about half rock and half ice, with rock at the center and ice outside.
4. a large rocky core with a thin layer (100 km thick) of ice and water over it.
1 points
Question 85
1.
When observing planetary motions from the Earth, the phrase direct motion refers to the
Answer
1. slow eastward motion of the planet from night to night compared to the background stars.
2. motion of the planet directly toward or away from the Earth in certain parts of the planet's orbit.
3. apparent westward motion of the planet (and the Sun, the Moon, and stars) across the sky due to the rotation of
the Earth.
4. slow westward motion of the planet from night to night compared to the background stars.
1 points
Question 86
1.
A particular photon has a wavelength of 450 nm and a second one has a wavelength of 580 nm. Which of the following
statements about the energies of these two photons is true?
Answer
1. The 450-nm photon has the higher energy.
2. The 580-nm photon has the higher energy.
3. The photon from the higher-intensity light source has the higher energy (regardless of wavelength).
4. All photons have the same energy, regardless of wavelength.
1 points
Question 87
1.
Stellar parallax is the
Answer
1. apparent shift seen in the position of a nearby star against more distant stars as the Earth orbits the Sun.
2. inferred change in the distance to a star as its light is dimmed by passing through an interstellar cloud.
3. difference between the apparent and absolute magnitudes of a star.
4. circular or elliptical motion of a star in a binary system as the two stars orbit each other.
1 points
Question 88
1.
In the Hertzsprung-Russell diagram, how does the position of a typical star change while it is at the main-sequence
phase of its evolution?
Answer
1. A star's position on the main sequence is determined only by its mass, not its age, so stars do not move along the
main sequence during evolution.
2. Stars move from upper right to lower left while they are on the main sequence.
3. Massive stars (4 solar masses) move toward the upper left as their luminosity increases, while lower-mass stars
move toward the lower right as their temperature decreases.
4. Stars move from upper left to lower right while they are on the main sequence.
1 points
Question 89
1.
When the northern hemisphere is experiencing winter, the
Answer
1. Earth is farther from the Sun than it is during the northern summer.
2. Earth is closer to the Sun than it is during northern summer.
3. southern hemisphere is experiencing winter also.
4. Earth is the same distance from the Sun as it is the rest of the year because Earth's orbit is circular with the Sun
in the center.
1 points
Question 90
1.
Which of the following statements comparing the Sun to the giant stars is NOT true?
(Refer to Figure 11-10, Comins and Kaufmann, Discovering the Universe, 8th ed.)
Answer
1. The giant stars have smaller absolute magnitudes than the Sun.
2. The giant stars are more luminous than the Sun.
3. The giant stars are larger than the Sun.
4. The giant stars are hotter than the Sun.
1 points
Question 91
1.
Why did the Soviet spacecraft survive for only a few minutes on the Venusian surface?
Answer
1. They were attacked and destroyed by native inhabitants, but the space agency is not telling the world.
2. The conditions of extreme pressure, corrosive atmosphere, and high temperatures severely damaged it.
3. They landed in very rugged terrain and were not able to land upright, and they became damaged when they
toppled over.
4. They landed very fast because there was insufficient atmosphere to slow down their descent.
1 points
Question 92
1.
The one significant observation Galileo made through his home-built telescope that convinced him that the planets
revolved around the Sun was the
Answer
1. appearance of mountains and craters on the Moon.
2. discovery of rings around the planet Saturn.
3. appearance of Venus following a cycle of phases, from crescent through quarter and gibbous phases to full.
4. appearance of the Milky Way as a mass of individual stars.
1 points
Question 93
1.
The clouds in the atmosphere of Venus consist primarily of
Answer
1. dust particles.
2. water.
3. droplets of carbon dioxide.
4. droplets of sulfuric acid.
1 points
Question 94
1.
How was the planet Uranus discovered?
Answer
1. Uranus was discovered by mathematical prediction using Newton's laws.
2. Uranus happened to pass close to Jupiter in the sky and was discovered by an astronomer studying Jupiter.
3. Uranus was discovered accidentally during a telescopic survey of the sky.
4. No
one knows—Uranus has been known since ancient times.
1 points
Question 95
1.
Which of the following statements about the Moon is true?
Answer
1. Earth can never be seen from one side of the Moon.
2. The Moon does not rotate on its axis.
3. The Moon can never pass through Earth's shadow.
4. One side of the Moon is always in darkness.
1 points
Question 96
1.
What scientific method was first used to discover the rings around Uranus?
Answer
1. direct photography of the rings from the Earth
2. occultation of a star as the planet and rings moved in front of it
3. spacecraft exploration of the planet
4. X-ray
photography from the Einstein satellite
1 points
Question 97
1.
What was the first direct evidence that some other solar-type stars might have planets?
Answer
1. faint pinpoints of light slowly circling some stars, as seen through the new 8- and 10-meter telescopes
2. cyclic Doppler shift variations in the spectra of several stars
3. slightly wavy path of a star through space, as if the star were being tugged by an orbiting planet
4. warped disks of dust and gas around some young stars
1 points
Question 98
1.
Harlow Shapley's original estimate of the distance from the Sun to the galactic center was incorrect because it did not
take scattering by interstellar dust into account. Shapley's original estimate was
Answer
1. too small because gas and dust tend to reflect light into the path of the beam, thus making stars look brighter and
nearer.
2. too large because scattering by dust made stars look redder—as though they were
highly Doppler-shifted and thus more distant.
3. too large because light scattering and absorption by dust made nearer stars look
dim—as though they were more distant.
4. too large because scattering by dust made stars look redder—as though they were
red giants of larger luminosity and thus farther away.
1 points
Question 99
1.
The one component of the material of the Milky Way Galaxy that prevents us from seeing and photographing the
galactic center at optical wavelengths is
Answer
1. hot hydrogen gas.
2. very cold hydrogen gas.
3. the glare of light from nearby stars.
4. interstellar dust.
1 points
Question 100
1.
According to Newton's laws, a force must be acting whenever
Answer
1. the direction of an object's motion changes.
2. time passes.
3. an object's position changes.
4. an object moves with some speed.