ASTR 45171

subject Type Homework Help
subject Pages 25
subject Words 3157
subject Authors Eric Chaisson, Steve McMillan

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page-pf1
The nova event is created by the helium flash.
Many astronomers now regard Pluto as just one of the largest of the thousands of
Kuiper Belt bodies found beyond Neptune.
The lunar mare are younger than any of the craters that sit in them.
In the Big Bang, about 75% of the normal matter by mass was hydrogen atoms, and the
other 25% almost entirely helium.
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Seyfert galaxies are the only type that produces gravitational lensing.
Space itself is expanding.
The vernal equinox marks the beginning of spring in the northern hemisphere.
Except for the Local Group, galaxies seem to be isolated and randomly in space.
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The Miller-Urey experiment relied on special conditions found only on Earth.
In Hubble's "tuning fork," spirals are on the parallel branches.
The parallax shift for all stars is very small.
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The shorter a wave's wavelength, the greater its energy.
William Herschel's original model for our Galaxy was based on counting stars.
The lunar mare radioactively date back to 4.6 billion years, at the origin of the Moon,
hence their dark color due to this aging.
The closest other galaxy to our solar system is the Sagittarius Dwarf.
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Planet-sized bodies have been detected around pulsars.
There is no evidence for plate tectonics on the Moon today.
The total mass of a galaxy tends to be only slightly larger than the visible mass.
The Kepler spacecraft has already identified thousands of exoplanet candidates.
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A star system can become a Type I supernova several times.
Most of the dark matter in the Galaxy lies in the disk and galactic center.
Like dark matter, dark energy will also retard the expansion of the universe.
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In the solar nebular theory, the dusty disk condensing around the Sun's equator became
the ecliptic plane in which the planets then formed.
Ganymede is the largest satellite in the solar system.
The current sunspot cycle is the most active in a century.
The closest terrestrial analog to hours of right ascension is angle of longitude.
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A star system may undergo two or more nova outbursts.
All four ring systems orbit the equators of Jovian planets outside their Roche limits.
Observations of sunspots at different solar latitudes prove that the Sun, like the gas
giants, rotates differentially.
There is as much mass in the voids between the stars as in the stars themselves.
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Atmospheric pressure on Mars is roughly half that of Earth's at sea level.
The Drake Equation seeks to estimate the number of technological civilizations in the
galaxy.
Any successful model for the formation of the solar system must explain why the orbits
of the planets have low eccentricities.
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What use are 21-cm radio waves to galactic astronomers?
A) They cut through the dusty cocoons to let us watch star birth.
B) We can reflect them off the core of the Galaxy.
C) Their Doppler shifts let us map the motions and locations of gas in the spiral arms.
D) They bounce off stars like our Sun to let us precisely measure their distances.
E) They pick up the cool, dark matter much better than can optical telescopes.
The weak magnetic fields around Europa and Ganymede were found during flybys of
A) Voyager 1.
B) Pioneer 10.
C) Cassini.
D) Galileo.
E) Stardust.
Small deviations in a planet's orbital motion
A) show we don't fully understand gravitational forces yet.
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B) indicate the presence of an extensive atmosphere.
C) indicate the presence of a powerful magnetic field.
D) imply the nearby presence of a massive body.
E) show the planet's orbit isn't stable.
Detailed measurements of the disk and central bulge region of our Galaxy suggest our
Milky Way is a
A) normal spiral galaxy.
B) barred spiral galaxy.
C) very flat elliptical galaxy.
D) very dusty irregular galaxy.
E) quasar.
For hydrogen, the transition from the first to third excited state produces
A) a red emission line.
B) a blue green absorption line.
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C) a violet emission line.
D) an infrared line.
E) an ultraviolet line.
In terms of composition
A) all planets condensed from the same nebula, and have similar compositions.
B) the jovian planets are more like the Sun than are the terrestrials.
C) the terrestrials are more like the Sun, since they formed close to it.
D) the Sun is unique, made of nothing but hydrogen and helium.
E) the jovian planets are made only of ice, and the terrestrials only of rock.
Before the decoupling,
A) the universe was transparent to radiation.
B) the universe was opaque to radiation.
C) protons and electrons combined to form atoms.
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D) there was more helium than hydrogen.
E) deuterium produced electrons and positrons.
What would happen if more mass was added to a 1.4-solar-mass neutron star?
A) It would erupt as a Type I supernova.
B) It could eventually become a black hole, via a hypernova explosion.
C) It would grow larger, temporarily becoming a red giant again.
D) All of its protons and electrons would turn into quarks.
E) It would blow off mass as an X-ray burster.
Our best stellar parallax measurements to date come from
A) the Hipparcos satellite.
B) ground based measurements taken six months apart.
C) radio interferometry.
D) the Keck telescope.
E) observations made by astronauts.
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The heaviest nuclei of all are formed
A) in the horizontal branch.
B) in dense white dwarfs.
C) during nova explosions.
D) in the ejection of matter in the planetary nebula.
E) in the core collapse that sets the stage for Type II supernovae.
As a radio source, the period of "pulsar Earth" is
A) 30 minutes.
B) 23 hours, 56 minutes.
C) 24 hours.
D) 29.5 days.
E) 365.25 days.
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In terms of dark, smoother mare and cratered highlands, which Jovian moon most
resembles the near side of our own?
A) Io
B) Europa
C) Ganymede
D) Triton
E) Titan
Venus' rotation on its axis
A) is the fastest of the terrestrial planets.
B) is clockwise, unlike most other solar system objects.
C) shows it is tidally locked in its orbit around the Sun.
D) is highly tilted to its orbital plane, causing large seasonal changes.
E) prevents us from seeing all of its surface features.
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The name of the NASA mission(s) that landed on Mars in 1976 was
A) Voyager.
B) Magellan.
C) Viking I and II.
D) Venera 14.
E) Galileo.
What will occur when the full moon is on the ecliptic?
A) a total lunar eclipse
B) a total solar eclipse
C) a partial solar eclipse
D) an annular lunar eclipse
E) a partial lunar eclipse if the Moon is at perigee
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The helium flash is followed within a few million years by the Type II supernova.
Cometary impacts with Jupiter
A) are impossible to observe from Earth.
B) have been observed from Earth at least twice.
C) are extremely rare.
D) are spectacular but do not teach us much.
E) would not be catastrophic if they happened on Earth.
Galactic disks appear blue because
A) they contain no G, K, or M dwarfs.
B) they contain only blue reflection nebulae.
C) dust obscures the longer, red, wavelengths.
D) O and B blue giants are much brighter than G, K, or M dwarfs.
E) dark matter gravitationally shifts all wavelengths towards the blue.
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In the critical density universe now proposed, the ratio of dark energy to matter is about
A) 1 to 100.
B) 1 to 1.
C) 3 to 1.
D) 10 to 1.
E) 1 to 5.
Collisions between galaxies are thought to
A) have stopped about 5 billion years ago.
B) be commonplace.
C) have never occurred.
D) be extremely rare.
E) have only occurred between 10 and 15 billion years ago.
page-pf13
The solution to the solar neutrino problem was
A) the Sun's core is cooling down, producing less neutrinos that expected.
B) the corona is opaque to much of the neutrino radiation.
C) the Earth's ozone layer absorbs 2/3 of the neutrinos in transit.
D) 2/3 of the neutrinos transform into a new type during the 8 minute trip to Earth.
E) our solar energy equations were just wrong, and needed much reworking.
What physical property of a star does the spectral type measure?
A) density
B) luminosity
C) temperature
D) mass
E) composition
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Without the greenhouse effect operating in our atmosphere,
A) we would not have to worry about any warming problems in the future.
B) Earth would have an average temperature of -23 degrees Celsius.
C) the ice in the polar regions would have melted long ago.
D) the ozone layer would not be weakening.
E) the Earth would have become much more like Venus long ago.
A jar filled with gas is placed directly in front of a second jar filled with gas. Using a
spectroscope to look at one jar through the other you observe dark spectral lines. The jar
closest to you contains
A) the hotter gas.
B) the cooler gas.
C) gas at the same temperature as the other jar.
D) the exact same gas as the other jar.
E) gas at very high pressure.
The magnetic field tilts of which two bodies are the most unusual?
page-pf15
A) Mercury and Earth
B) Jupiter and Saturn
C) Uranus and Neptune
D) Saturn and Pluto
E) Mars and Saturn
A meteor is
A) a chunk of space debris that has struck the ground.
B) a streak of light in the atmosphere.
C) an icy body with a long tail extending from it.
D) a chunk of space debris orbiting the Earth.
E) an irregularly shaped body, mostly found orbiting between Mars and Jupiter.
In structure, our Milky Way is most similar to
A) the Large Magellanic Cloud.
page-pf16
B) an upscale version of a globular cluster.
C) M31, the Andromeda Galaxy.
D) the Orion nebula.
E) none of these.
All globular clusters in our Milky Way are about how old?
A) less than a million years
B) ten-fifty million years old
C) one to three billion years old
D) around ten billion years old
E) a variety of ages, from newly born to twenty billions years old
What is true of galaxies at the larger redshifts compared to ones nearby?
A) They appear smaller and more irregular.
B) They appear larger and more regular.
C) They are redder.
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D) They are almost all ellipticals.
E) They are mostly giants.
Compared to our own Galaxy, elliptical galaxies
A) show more internal structure.
B) have bluer stars.
C) have more dust.
D) have no arms, but a better defined disk.
E) show no evidence of ongoing star formation.
The atmosphere of Titan is composed mostly of
A) oxygen.
B) methane.
C) carbon dioxide.
D) hydrogen.
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E) nitrogen.
So far, beyond the solar system the extrasolar planets found have been mostly
A) large jovians orbiting solar-type stars about where our jovians are found.
B) large jovians very close to their star.
C) terrestrials very close to their star, and transiting its disk.
D) terrestrials with very elongated, distant orbits like comets.
E) brown dwarfs much more massive than Jupiter.
According to the Solar Nebula theory, planets
A) should be randomly oriented to their star's equator.
B) will revolve opposite the star's rotation.
C) should be a common result of star formation.
D) should be extremely rare.
E) should orbit perpendicular to their star's equator.
page-pf19
The gas density in an emission nebula is typically about how many particles per cc?
A) dozen
B) hundred
C) thousand
D) hundred thousand
E) million
The flattest of the ellipticals are class
A) E0.
B) SBO.
C) E7.
D) E9.
E) SBF.
page-pf1a
A cluster with a lot of Type O and B stars, but no bright K or M stars, is very ________.
It takes the Pluto-Charon system ________ to rotate around its common center of mass.
If the Moon is on the ecliptic, new, and at its farthest distance from Earth, we will get
a(n) ________ solar eclipse.
What is the significance of large percentage of oxygen in Earth's atmosphere?
page-pf1b
How does the Solar Nebula theory explain the formation and orbital properties of
planets?
Most radio galaxies belong to Hubble's class ________.
The first quarter moon rises about noon today; what will its phase be, and when will it
rise tomorrow?
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Ptolemy's model was ________, with the Earth fixed in the center of the universe.
The greatest rift valley system yet found is ________ on Mars.
What element is notably deficient in Saturn's atmosphere, and why?
page-pf1d
Suppose an extrasolar planet's orbit around its star is edge-on to our line of sight. How
is it detected, and what information can be obtained in this case?
Which class of stars probably has too small a habitable zone for life to arise?
Why do Newton's Laws show a force must be acting on the planets?
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While the photosphere produces chiefly visible light, most coronal energy is in the form
of ________.
In general, wind direction ________ between adjacent bands in Jupiter's atmosphere.
Mars is often called a "midway world," similar in some respects to Earth, and in others
to our Moon. Explain.
Why were globular clusters so vital to Harlow Shapley's success?
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How are Jupiter and Saturn similar?
A solar ________ is a sudden, violent disruption around sunspots, releasing a
tremendous amount of energy in almost all wavelengths.
List the two major regions of the near side of the Moon, as seen with the naked eye.

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