ASTRON 24370

subject Type Homework Help
subject Pages 24
subject Words 2712
subject Authors Eric Chaisson, Steve McMillan

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page-pf1
The scarps on Mercury are extremely similar to the cratered lunar highlands in
appearance.
The particles in Saturn's E ring probably come from volcanic eruptions on Enceladus.
Like the RR Lyrae stars, Cepheids are all similar in luminosity, hence their use in
measuring stellar distances.
All four of Jupiter's big moons, like most moons in the solar system, revolve clockwise
(retrograde) around their planet's equator.
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Mercury's rotation and revolution are an example of a 3:2 resonance.
Mars appears red in color because of refraction of light by its atmosphere, much like the
color of the totally eclipsed Moon.
Olbers's paradox is solved in part by the fact that the universe is neither infinitely large
nor infinitely old.
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The Cassini probe Huygens made a soft landing on Titan.
Carbon dioxide is the predominant atmospheric gas on Venus.
Active galaxies emit most of their radiation as visible light.
Around us in the galactic plane, we find stars of a variety of ages and compositions.
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Aurorae like ours have been seen above the poles of Jupiter and Uranus.
Planets are expected to be found orbiting most Population II stars.
From the best current data, we infer the universe will expand forever.
From Earth, the Sun and Moon have about the same angular diameter.
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The tectonic surface features we see on Triton are similar to the grooves of Ganymede.
Besides Mars, exobiologists find Europa also a good candidate for life.
Of normal matter, about 25% of it by mass is still primordial helium even today.
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All the planet's orbits are evenly spaced.
All the planets revolve around the Sun in the same direction, except for Venus and
Uranus.
The rotation of the magnetic fields of the jovian planets is believed to also give us the
rotation rate of the planet's core.
The presently known laws of physics clearly describe the conditions inside a black
hole's event horizon.
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Synchrotron radiation is the major source of energy for active galaxies.
The Solar Neutrino Problem is that we observe more neutrinos than predicted.
The Sun's radius is one astronomical unit by definition.
Binary star systems are considered good candidates in SETI.
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Einstein's prediction of the curvature of space was confirmed by the 1919 total solar
eclipse.
A star with a right ascension of 2.6 hrs will rise 2.6 hours after the vernal equinox.
The crust on the near side of the Moon is on average thinner than the crust on the far
side, due to our tidal pull on the Moon.
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The density of the universe is large enough that gravity alone will eventually halt its
expansion.
M31 in Andromeda is a bigger version of our Galaxy, and the largest member of the
Local Group.
Quasars appear to have very large red shifts, and are receding at nearly the speed of
light.
The stars of the halo are all old, and those of the disk are all new.
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Sunspots usually come in pairs of north and south magnetic poles.
Because of its axial tilt and more elliptical orbit, Mars' polar caps change size even
more than the Earth's do.
At decoupling, the electrons and protons were made from neutron decay.
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To find the ________ velocity, we must combine proper motion and parallax data.
Novae and Type II supernovae are essentially the same phenomena.
The scarps on Mercury were probably caused by
A) tectonic activity.
B) meteorite bombardment.
C) a tidal bulge.
D) volcanism.
E) the crust cooling and shrinking.
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From inside out, which is in the correct order for the structure of the Sun?
A) core, convective zone, radiative zone
B) core, photosphere, radiative zone, corona
C) core, radiative zone, convective zone, chromosphere
D) core, chromosphere, photosphere
E) core, convective zone, radiative zone, granulation
During a period of high solar activity, the corona
A) disappears.
B) is more irregular.
C) cools almost to the temperature of the photosphere.
D) becomes smooth and even.
E) shrinks to half its normal size.
In the Grand Unified Theory, the superforce was
A) only dark energy.
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B) a union of the weak and electromagnetic forces.
C) a union of all matter and energy.
D) a union of the strong and weak nuclear, and electromagnetic forces.
E) was only in effect at low energies.
That Polaris will not always be the pole star is due to
A) the sidereal day being shorter than the solar day.
B) precession shifting the celestial pole.
C) the Moon following the ecliptic, instead of the equator.
D) the Earth's revolution being slightly less than exactly 365.25 days.
E) the Solar winds blowing the Earth farther away from the Sun.
The nucleus of a comet is typically
A) a few meters in diameter.
B) very durable, made of iron.
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C) a few kilometers in size, and very low in density.
D) a few hundred kilometers across, and bright, shiny white from its ices.
E) located between the orbits of Mars and Jupiter.
The brightest stars in aging globular clusters will be
A) core stars of planetary nebulae.
B) massive blue main-sequence stars like Spica.
C) blue stragglers.
D) red supergiants like Betelgeuse and Antares.
E) blue supergiants like Rigel and Deneb.
If a star was the same size as our Sun, but was 81times more luminous, it must be
A) twice as hot as our Sun.
B) three times hotter than the Sun.
C) four times hotter than the Sun.
D) nine times hotter than the Sun.
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E) 81 times hotter than the Sun.
Most SETI searches are done at
A) X-ray wavelengths.
B) infrared wavelengths.
C) visual wavelengths.
D) radio wavelengths.
E) gamma wavelengths.
What is true of spiral galaxies?
A) They are much less common at larger redshifts.
B) They are relatively rare in regions of high galaxy density.
C) They are only found in the center of rich galaxy clusters.
D) They have never been seen to have large redshifts.
E) They evolve from giant ellipticals.
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In this diagram, the galaxy at the left side is a(n)
A) Seyfert.
B) spiral.
C) barred spiral.
D) elliptical.
E) irregular.
Which statement is true?
A) Our Sun is a Population II star.
B) The bright blue stars that dominate the sky are Population I stars.
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C) Population I stars lie outside the galactic disc.
D) Population I stars are the brightest stars in the globular clusters.
E) Population II stars probably have terrestrial planets around them.
Which of these is emitted when an electron falls from a higher to lower orbital?
A) another electron
B) a positron
C) a neutrino
D) a photon
E) a graviton
Valles Marineris is the most striking example of a(n)
A) impact crater.
B) shield volcano.
C) oceanic trench.
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D) rift valley.
E) scarp.
An extraterrestrial observer would pick up the strongest radio signals when
A) the Earth was at perihelion.
B) North America was either rising or setting for the observer.
C) North America was directly in front of the observers.
D) at new or full moon.
E) Saturday Night Live is on.
When a star's inward gravity and outward pressure are balanced, the star is said to be
A) in gravitational collapse.
B) in thermal expansion.
C) in rotational equilibrium.
D) in hydrostatic equilibrium.
E) a stage 2 protostar.
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Most stars in our part of the Galaxy are formed
A) alone.
B) in open clusters of a few dozen.
C) in associations of thousands of stars across a spiral arm of the Galaxy.
D) in globular clusters of millions of stars.
E) in a singular event just after the Big Bang.
Which type of galaxy has a stellar disk, but without gas and dust?
A) E0
B) E7
C) Irr I
D) S0
E) SE
page-pf14
Density is defined as
A) mass per unit volume.
B) weight per square inch.
C) size divided by weight.
D) mass times weight.
E) weight divided by the planet's radius.
What key event happened during the decoupling epoch?
A) Pairs of neutrons and protons were created.
B) Electrons and positrons were created.
C) Expansion cooled the universe enough that protons could capture electrons in orbit.
D) Dark energy accelerated the cosmos on to infinity.
E) The universe underwent a brief period of very rapid expansion.
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What problem does adaptive optics correct?
A) defects in the optics of the telescope, such as the original Hubble mirror
B) the opacity of the Earth's atmosphere to some wavelengths of light
C) the light pollution of urban areas
D) turbulence in the Earth's atmosphere that creates twinkling
E) chromatic aberration due to use of only a single lens objective
Suppose a large flare is detected optically. How long until radio interference arrives?
A) simultaneously
B) 8.5 minutes later
C) about 12 hours
D) about four days
E) no relation between the two
The darkness of the night sky in an infinite universe is addressed in
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A) General Relativity.
B) Special Relativity.
C) Steady State Physics.
D) Olbers's paradox.
E) the Cosmological principle.
Of the jovian planets, which generates the least internal heat?
A) Jupiter
B) Saturn
C) Uranus
D) Neptune
E) Pluto
A galaxy with little cool gas or dust and no evidence of ongoing star formation is most
likely a(n)
A) elliptical.
page-pf17
B) spiral.
C) barred spiral.
D) irregular.
E) Seyfert.
A loop of gas following the magnetic field lines between sunspots' poles is
A) a flare.
B) a ray.
C) a coronal hole.
D) a prominence.
E) a coronal mass ejection.
The largest moon in the solar system, bigger but not as massive as Mercury, is
A) Europa.
B) Ganymede.
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C) Callisto.
D) Titan.
E) Triton.
Emission nebulae are created by gas absorbing ultraviolet energy from the hot young
stars within them, such as in the Orion Nebula.
The star's color index is a quick way of determining its
A) density.
B) luminosity.
C) mass.
D) temperature.
E) composition.
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Considering both longevity and luminosity, which of these stars would be the most
likely candidate for seeking extraterrestrial intelligence?
A) Spica, a B3 main-sequence star
B) 61 Cygni, a K2 main-sequence star
C) Sirius B, a white dwarf
D) Antares, a M3 supergiant
E) Barnard's star, a M5 dwarf
A white dwarf has the mass of the Sun and the volume of
A) Jupiter.
B) Earth.
C) Mars.
D) the Moon.
E) Eros.
page-pf1a
If Ωo is less than one, then
A) the universe is closed, and must recycle.
B) the universe will expand forever.
C) no matter could have existed.
D) only dark energy exists in the universe.
E) there is more matter than energy in the universe.
In the M class stars, we find ________ absorption lines not seen in hotter stars.
The greater the mass of the foreground cluster of galaxies, the ________ the warping of
the images of the distant galaxies behind it.
page-pf1b
An AM station is broadcasting at 980 kHz, while an FM station up the road is assigned
98 MHz. How do their carrier waves compare?
What features are conspicuously absent from the far side of the Moon? Why?
How far above or below the equator can the Sun appear to move? Why?
Compare the way an optical and radio astronomer would map the Galaxy.
page-pf1c
If its parallax is 1", then the distance to the star is ________ light-years.
How far above or below the ecliptic can the Sun move?
The most luminous objects known in the universe are ________.
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A wave with a frequency of 2 Hz will have a period of ________.
In the cosmological principle, ________ implies that the direction the observer faces
makes no difference on the grandest scale.
Virtually the entire disk of the Galaxy has been mapped using the ________
wavelength.
The greatest gravitational lensing is produced by the ________ that lie in the centers of
massive galaxies.
page-pf1e
An example of the universe's large-scale filamentary structure is the ________.
The ________ Belt bodies orbit beyond Neptune, but like the planets stay close to the
ecliptic plane and in fairly circular orbits.
The Tully-Fisher relation uses the rotational speed of the galaxy to measure its
________.

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