ASTRON 48760

subject Type Homework Help
subject Pages 27
subject Words 3021
subject Authors Eric Chaisson, Steve McMillan

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page-pf1
The universe has been expanding at the same rate since its formation.
Although sunspots are cooler areas in the photosphere, when they increase in number
that tells us the Sun is becoming more active.
Earth-like planets have been observed outside our solar system orbiting in the habitable
zone.
Light from distant stars that must pass through dust arrives bluer than when it left its
star.
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No stars have yet been observed that have more than one exoplanet.
All stars have roughly the same luminosity after the helium flash.
When we see a doubling of the image of single quasar, the body creating the gravity
lens is just a brown dwarf close to us.
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COBE found the cosmic microwave background to be absolutely uniform everywhere.
Only people in the Moon's umbral shadow can see a total solar eclipse.
The axial tilts of Uranus and Neptune are similar.
The definition of "life" requires only that an entity be able to reproduce itself.
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Globular clusters contain mostly blue stars.
One source of the energy for volcanism and plate tectonics is radioactivity in the Earth's
interior.
Saturn is less dense than water.
Nearby active galaxies, such as Centaurus A, are likely the mergers between colliding
galaxies.
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The Big Bang has time in primordial nucleosynthesis to make only H and He in
abundance.
As the name quasi-stellar radio sources implies, all quasars are strong radio sources.
The Miller-Urey experiment did produce amino acids and proteins.
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Elements heavier than iron are formed mainly in supernovae.
Molecular lines, such as TiO, are only found in very hot stars.
The Earth lies close to the center of the Galaxy.
A star may undergo two or more red giant expansion stages.
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The Sun's structure is uniform throughout its interior, with no evidence of different
layers.
Even if a probe were in a stable orbit near a black hole, we would still observe its
signals red shifted by the gravitational field of the black hole.
A 100 million-year-old open cluster will no longer contain any O-type stars.
The Earth's hotter, inner core is liquid and its cooler, outer core is solid.
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Researchers estimate that there is more total mass in the Kuiper Belt than in the asteroid
belt.
Although mass transfer can occur in binary stars, the small mass change does not
impact the evolution of either companion.
Most stars are single stars like our own.
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The retrograde orbit of Triton dooms it to spiral inward toward Neptune, perhaps
someday to make a ring system.
Galileo is credited with designing the first reflector telescope.
The longer the period of pulsation for a Cepheid, the more massive and luminous the
variable giant star is.
The Galileo probe into Jupiter's atmosphere found more water than expected.
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Globular clusters are dominated by bright red supergiants at the top right of the H-R
diagram.
Supernova 1987A was the first supernova observed by astronomers since Galileo first
turned a telescope to the heavens.
In the sky, declination is measured in degrees north or south of the celestial equator.
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What is the nearest huge cluster of thousands of galaxies, to which the Local Group
may belong?
A) The Great Wall
B) Coma Cluster
C) Virgo Cluster
D) Corona Borealis Cluster
E) Sagittarius Cluster
For finding the distances to globular clusters, Harlow Shapley used
A) eclipsing binaries.
B) planetary nebulae.
C) Type I supernovae.
D) RR Lyrae variables.
E) Population I classical Cepheids.
What is thought to lie at the center of Jupiter?
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A) a hot sea of liquid metallic hydrogen
B) a solid core of crystalline helium
C) a massive core of rocky materials with some iron mixed in
D) gaseous hydrogen and helium, for Jupiter is not differentiated like Earth
E) a fusion core like the Sun's, with hydrogen being turned into helium
In what sense are the quasars "quasi-stellar"?
A) Their energy production is hydrogen-helium fusion, like main-sequence stars.
B) They are upscale versions of O stars, yet hundreds of times more massive.
C) Their luminosity comes from the millions of supergiants that compose them.
D) Their spectra are like those of ordinary stars.
E) In short time exposures, their images looked stellar.
Which planet by itself contains the majority of mass of all the planets?
A) Jupiter
B) Saturn
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C) the Earth
D) Venus
E) Uranus
If we know the average separation and period of revolution for a binary system, we can
then measure
A) the actual sizes of the two stars.
B) the total mass of the system.
C) their absolute magnitudes.
D) the actual mass of both individual stars.
E) the actual luminosity of each star.
Exoplanets known as super-Earths
A) have masses comparable to that of Jupiter.
B) have masses comparable to that of Neptune.
C) have masses 2-10 times that of Earth.
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D) orbit extremely massive stars.
E) have yet to be observed.
The Cassini Division is a gap in Saturn's rings caused by
A) Saturn's excess heat.
B) two shepherding moons.
C) Saturn's magnetic field.
D) gravitational interaction with Mimas.
E) the icy ring particles melting.
According to Hubble's Law, a galaxy with a recession velocity of 25,000 km/s will be
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A) 100 million pcs away.
B) 400 million pcs away.
C) 700 million pcs away.
D) 1000 million pcs away.
E) less than 1 million pcs away.
How does the energy of the cosmic microwave background compare to the energy
radiated by all the stars and galaxies that ever existed?
A) They are very close to being equal.
B) 73% cosmic background, 27% starlight
C) about ten times more from the Big Bang than from stars and galaxies
D) The starlight now dominates the background, as your eyes show clearly.
E) We have no way of comparing matter and energy this way.
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A billion-solar-mass black hole would still have a radius of only
A) 20 AU.
B) 15 pc.
C) 150 kilometers.
D) 3 kpc.
E) two million light years.
The surface of Europa is most like the Earth's
A) tundra.
B) deserts.
C) Arctic Ocean.
D) Himalayan peaks.
E) South Pole.
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The deepest depression found on the surface of Mars is the
A) Mariana Trench.
B) Caloris basin.
C) Valles Marineris rift.
D) Hellas Basin.
E) Mare Crisium.
What is the name of the temperature scale that places zero at the point where all atomic
and molecular motion ceases?
A) Fahrenheit
B) Celsius
C) Kelvin
D) Centigrade
E) Ransom
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Adams and Leverrier both predicted the position of Neptune, based on its effects on
A) the Sun.
B) Jupiter.
C) Saturn.
D) Uranus.
E) Pluto.
Rotation curves for spiral galaxies show
A) they are slowing down.
B) rotation speed drops off further from the nucleus.
C) most have dark halos.
D) most of the mass lies in the nucleus.
E) no relation to mass.
Although theory says a massive black hole with an accretion disk should be emitting
X-rays, many black holes emit
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A) mostly in the infrared.
B) only in the visible.
C) mainly in the gamma.
D) virtually no radiation at all.
E) equally across the entire electromagnetic spectrum.
Only type O stars are hot enough to show ionized ________ in their spectra.
The far side of the Moon was first mapped
A) by Galileo in 1610 with his first telescope.
B) by the Apollo astronauts on the first orbit of the Moon with Apollo 8.
C) by early Russian spacecraft.
D) by NASA with its Lunar Orbiters in the 1960s.
E) by William Herschel with his large reflectors in the early 1800s.
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In July 2011, the Dawn probe entered orbit around
A) the asteroid Ceres.
B) the asteroid Vesta.
C) the comet Wild.
D) the asteroid Ida.
E) the asteroid Gaspra.
Only A type stars show hydrogen lines in their spectra.
The dark halo is now believed to extend at least
A) 8 kpc.
B) 15,000 light years.
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C) 15 kpc.
D) 100,000 light years.
E) 50 kpc.
Which of the following is NOT a reason to use a reflecting telescope rather than a
refractor?
A) Lenses are subject to chromatic aberration.
B) Lenses are harder to focus than mirrors.
C) Lenses absorb light, while mirrors do not.
D) Heavy lenses, which can only be supported at their edges, tend to deform under their
own weight.
E) A lens must have two precision surfaces; a mirror needs only one.
The astronomer who originally classified galaxies into S, E, and Irr was
A) William Herschel.
B) Harlow Shapley.
C) Henrietta Leavitt.
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D) Edwin Hubble.
E) Carl Sagan.
On the H-R diagram, red supergiants like Betelgeuse lie
A) at the bottom left.
B) at the bottom right.
C) at the top left.
D) at the top right.
E) They can't be plotted, for they are not main sequence.
The location of the Galactic Center was first found by Harlow Shapley with
A) radio emissions from Sagittarius A.
B) Cepheids of population I in the spiral arms.
C) RR Lyrae variables in the globular clusters.
D) planetary nebulae in the open clusters.
page-pf17
E) infrared observations of the heat from its accretion disk around the black hole.
The spacecraft Cassini went into orbit around
A) Jupiter.
B) Saturn.
C) Uranus.
D) Neptune.
E) Pluto.
Which of these does not exist?
A) a million solar mass black hole
B) a 6 solar mass black hole
C) a 1.8 solar mass neutron star
D) a 1.5 solar mass white dwarf
E) a 0.06 solar mass brown dwarf
page-pf18
The two outer jovian planets appear bluish in color because
A) methane gas in their atmospheres absorbs red light well.
B) ammonia absorbs blue light well.
C) hydrogen and helium are both blue in large concentrations.
D) dust motes in their atmospheres scatter blue well, just as in our own blue sky.
E) from their distance, the Sun would appear hotter and bluer than from Earth.
If Vega is apparent magnitude zero, and Deneb first magnitude, then
A) Vega is about 100 brighter than Deneb.
B) Deneb is one magnitude brighter than Vega.
C) Vega is 2.5 brighter than Deneb.
D) Deneb must be a main sequence star, and Vega a giant.
E) Vega must be 2.5 hotter than Deneb.
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As you watch a star, you see it move 15 degrees across the sky. How long have you
been watching it?
A) 1 hour
B) 3 hours
C) 15 minutes
D) 15 seconds
E) 1 minute
As a spaceship's velocity gets closer to the speed of light with respect to an external
observer, that observer will report that
A) its length will increase and its clock will run more slowly.
B) its length will decrease and its clock will run faster.
C) its length will increase and its clock will run faster.
D) its length will decrease and its clock will run more slowly.
E) None of these will happen.
page-pf1a
Which of the following is not one of Hubble's types of galaxies?
A) normal spirals
B) barrel spirals
C) Seyfert spirals
D) irregular type II
E) dwarf ellipticals
In its most energetic phase, a quasar can probably only last
A) a few days.
B) a few years.
C) a few thousand years.
D) a few million years.
E) a few billion years.
Interstellar dust clouds are best observed at what wavelength?
page-pf1b
A) Radio and infrared
B) visible only
C) UV and infrared
D) Radio and X-ray
E) Visible and UV
The ________ in our atmosphere is the result of photosynthesis by plants.
The vast majority of galaxies in the universe are ________ and ________.
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The ________ blows out of the coronal holes.
That pulsars are losing rotational energy from magnetic drag is shown as they
________.
Geminga pulses strongly in gamma rays, and may be the closest neutron star. Why is it
unusual?
What two properties of the stars were Hertzsprung and Russell comparing?
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Why would spiral galaxies be less common now than in the early universe?
Explain the difference between radial and transverse velocities.
In a galaxy like ours, the best place for life to form would be in the ________.
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Every solar type star ever formed still shines in the Milky Way Galaxy, yet our naked
eyes see stars that generally are much younger than the Sun. Explain.
In general, the ________ lunar craters sit atop the mare.
The second most abundant element in the solar system is ________.
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Only ________ stars have rotation periods of less than a second.
Compared to Jupiter, the element ________ is notably less common in Saturn's
atmosphere, perhaps condensing to fall toward the core as rain.
Dividing a distant galaxy's velocity by its distance will give you ________.
It is likely that both Pluto and Triton were originally ________.
page-pf20
Contrast the open vs. globular clusters in terms of age, color, galactic distribution,
chemical composition, and populations.
How would Ptolemy explain the rising of the Sun? Contrast this to Copernicus'
explanation of the same event.
Are sunspots really dark and cool?

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