ASTRON 94121

subject Type Homework Help
subject Pages 24
subject Words 3023
subject Authors Eric Chaisson, Steve McMillan

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Changes in the predicted motion of Uranus led to the search for an eighth planet.
Solar mass stars eventually become hot enough for carbon nuclei to fuse together.
The "Great Wall" is the structure in the Large Magellanic Cloud near where Supernova
1987A occurred.
The chromosphere is faint because of its low density.
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It appears that the universe is composed of nearly three times as much dark energy as
normal and dark matter combined.
The Big Bang was an expansion of matter into empty space.
Because of the great masses and speeds involved, Newton's laws are useless in
measuring the mass of a galaxy.
Spectroscopy of a star can reveal its temperature, composition, and line-of-sight
motion.
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The continuing rise of carbon dioxide concentration in our troposphere is leading to
worldwide cooling as dry ice forms at the poles.
The Milky Way is at the center of our Local Supercluster.
In Ptolemy's geocentric model, the planet's motion along its deferent is all that is
needed to understand retrograde motion.
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The number of Type I and Type II supernovae observed are approximately equal.
The spiral arms are sites of continuous new star formation, accounting for their blue
color and pink emission nebulae.
The dust particles have exactly the same chemical composition as the gases of the
interstellar medium.
The main sequence is luminosity class V.
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Galaxies look the same whether viewed in visible or X-ray wavelengths.
Low-mass stars may become hundreds of times more luminous as giants than they were
on the main sequence.
Mt. Palomar's 200" Hale telescope is the largest reflector now in service.
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The COBE satellite was designed to image the microwave cosmological background
radiation and thus study the earliest stages of the universe.
If the inflation theory is correct, the geometry of the universe is flat and Euclidean.
In the cores of the most massive stars, the electrons and protons fuse together and form
neutrons.
The photosphere is the coolest layer close to the Sun, for the radiation of visible light
allows it to cool off efficiently.
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Most lunar craters are volcanic in origin.
Organic molecules can only be made by living things.
William Herschel made the first map of the Galaxy about 200 years ago.
There are large amounts of superhot intergalactic matter.
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It is harder to map the structure of the Milky Way in visible wavelengths than with
radio and infrared waves.
The Allen Telescope Array is one of the many radio searches for extraterrestrial life.
One characteristic of the terrestrial planets is their extensive moon systems.
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The mirrors for X-ray telescopes are the same shape as those of optical reflectors.
The more its central black hole was fed, the more likely the galaxy was to show up as a
quasar.
Seismic P-waves can travel through both solid and liquid materials.
Where was supernova 1987A located?
A) in the Orion Nebula, M42
B) in Sagittarius, near the Galactic Nucleus
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C) in our companion galaxy, the Large Magellanic Cloud
D) in M13, one of the closest of the evolved globular clusters
E) near the core of M31, the Andromeda Galaxy
It is diffraction that limits the ________ of a telescope of a given objective diameter.
A) magnification
B) light grasp
C) resolution
D) aperture
E) interference
Which of these variable stars would be classified as a Cepheid?
A) a B supergiant with a period of 0.14 days
B) an F giant with a period of 14 years
C) a G giant with a period of 14 hours
D) a K giant with a period of 14 days
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E) an M supergiant with a period of 140 days
Collisions between galaxies
A) are much rarer than collisions between stars.
B) can turn elliptical galaxies into spirals.
C) cause large numbers of stars to collide and explode.
D) cause the gas and dust clouds to collide, leading to rapid star formation.
E) are the best explanation for gamma-ray burst events.
The most distant objects in our solar system are
A) in the Kuiper Belt.
B) the jovians.
C) in the Oort Cloud.
D) short period comets.
E) the Trojan asteroids.
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Consider this diagram. Which statement is true?
A) The amplitude is 4 and the wavelength is 6.
B) The amplitude is 6 and the wavelength is 4.
C) The amplitude is 8 and the wavelength is 6.
D) The amplitude is 4 and the wavelength is 12.
E) The amplitude is 8 and the wavelength is 12.
What makes the Crab Nebula pulsar unusual among other pulsars?
A) It is the fastest spinning known pulsar.
B) It is a magnetar, with far more intense magnetic fields than any other.
C) It is relatively bright in shorter wavelengths, like visible and X-rays.
D) Its period is much less regular than other pulsars.
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E) It is the oldest known pulsar.
How much brighter will a 4th magnitude star appear than a 6th magnitude star?
A) 6.25 times
B) 2.0 times
C) 2.5 times
D) 16 times
E) 8 times
An X-ray burster is similar to a nova.
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If we are optimistic in our assumptions about the development of life and intelligence,
then the number of technological civilizations currently in the galaxy should equal the
A) average lifetime of a civilization.
B) number of stars forming per year.
C) average number of planets per star.
D) number of stars in the galaxy's habitable zone.
E) average number of planets that produce life.
Which statement about asteroids is not true?
A) They vary considerably in composition, reflectivity, and size.
B) Most stay between the orbits of Mars and Jupiter.
C) Some have satellites of their own.
D) Their images become blurry due to outgassing as the Sun heats them up.
E) Earthgrazers can cross not only our orbit, but even those of Venus and Mercury.
After the Lunar Reconnaissance Orbiter (LRO) crashed into the moon, its sister
spacecraft LCROSS detected an amount of water in the ejecta
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A) comparable to soggy ground on Earth.
B) comparable to fertile soil on Earth.
C) comparable to dried-up lake beds on Earth.
D) less than is contained in desert sand on Earth.
E) Actually, no water was detected at all.
The speed of light in a vacuum is
A) 300,000 km/sec.
B) 768 km/hour.
C) 186,000 miles per hour.
D) h = E/c.
E) not given.
Most astronomers now believe the demise of the dinosaurs 65 million years ago was
caused by a large asteroid impacting the Yucatan peninsula area.
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The star Thuban in Draco
A) lies as the center of the precession cycle.
B) was an excellent north pole star in 3,000 BC.
C) is brighter than Polaris.
D) lies halfway between the bowls of the Big and Little Dippers.
E) is used to locate the vernal equinox.
The largest asteroid, and probably the only one to be a spherical "world" is
A) Eros.
B) Ida.
C) Vesta.
D) Ceres.
E) Gaspra.
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What is true of a blackbody?
A) It appears black to us, regardless of its temperature.
B) Its energy is not a continuum.
C) Its energy peaks at the wavelength determined by its temperature.
D) If its temperature doubled, the peak in its radiation curve would be doubled in
wavelength.
E) It has a complete absence of thermal energy.
A cloud fragment too small to collapse into a main sequence star becomes a
A) white dwarf.
B) pulsar.
C) T-Tauri object.
D) brown dwarf.
E) planet of another star.
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Stars of less than 8 solar masses will not go supernova.
The amount of diffraction and thus the resolution of the telescope depends upon
A) the wavelength used and the size of the main telescope objective lens or mirror.
B) the design of the telescope.
C) whether the telescope is a reflector or refractor.
D) the brightness of the object.
E) the size and sensitivity of the CCD chip used for imaging.
Planetary transits of exoplanets are rare because
A) most exoplanets are smaller than Pluto.
B) most extrasolar systems are not seen edge-on.
C) our telescopes are not powerful enough to detect them.
D) most stars are too bright for us to detect a planetary transit.
E) the Earth's atmosphere interferes with our observations of transits.
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The mass range for neutron stars is
A) 0.08 to 0.4 solar masses.
B) 0.4 to 3 solar masses.
C) 1.4 to 3 solar masses.
D) 3 to 8 solar masses.
E) 6 to 11 solar masses.
The number of confirmed extrasolar planets
A) is about 600, and is not expected to rise very much.
B) has been decreasing as some observations thought to be planets have been
disproven.
C) is about 800, and is rising slowly, as observations are quite difficult.
D) was about 800 at the time of publication but is rising rapidly due to new
observations by the Kepler spacecraft.
E) is zero; there are observations thought to be of extrasolar planets but none has yet
been confirmed.
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Which Jovian moon shows the most diverse terrain, suggesting a violent impact broke it
into many pieces, some of which reformed it as a jumbled puzzle?
A) Io
B) Ganymede
C) Enceladus
D) Miranda
E) Triton
In the proton-proton cycle, the helium atom and neutrino have less mass than the
original hydrogen. What happens to the "lost" mass?
A) It is recycled back into hydrogen.
B) It is ejected into space.
C) It is converted to energy.
D) It is transformed into electrons.
E) Conservation of mass dictates no mass can be lost.
page-pf15
In what part of our atmosphere do we live?
A) troposphere
B) stratosphere
C) mesosphere
D) ionosphere
E) exosphere
Almost all of our atmospheric gases lie in the
A) ionosphere.
B) stratosphere.
C) troposphere.
D) ozone layer.
E) mesosphere.
page-pf16
The initial mass of a protostar generally determines the star's future evolution. But in
some cases, what can alter this process?
A) The star may be isolated in space, far from other influences.
B) The star may be in a spectroscopic binary system.
C) The star may gain mass by passing through a dark cloud.
D) The star may collide with another, unrelated star.
E) The star may drift away from the other stars in its formation cluster.
Voyager 1 was unable to image Titan's surface because
A) of 'smog" in Titan's atmosphere.
B) of Titan's high reflectivity.
C) the moon was in shadow during the mission.
D) the cameras were damaged by Saturn's magnetic field.
E) volcanic activity spewed sulfur clouds, obscuring the surface.
Which of these would typically be the brightest star in a young open cluster?
page-pf17
A) G2V
B) B1V
C) A2Ib
D) K3II
E) M3Ia
The Drake Equation is attempting to find
A) the number of planets in the Milky Way Galaxy.
B) the number of planets with life on them in the whole universe.
C) the number of stars that might have planets orbiting them.
D) the number of technological civilizations in the Galaxy at a given moment.
E) the total number of terrestrial planets ever created.
Why are Mars' seasons more extreme than those of the earth?
A) Mars' seas dried up long ago.
B) Mars' axial tilt is slightly more than our 23.5 degrees.
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C) Mars' orbit is more eccentric than our almost circular one.
D) Mars' weather is affected by evaporation from the polar ice in its summer.
E) All of these contribute to the huge seasonal changes that Mars experiences.
How long does it take an M-type star to reach the main sequence, compared to a
solar-type star?
A) a tenth as long
B) about the same, 30 million years
C) about twice as long
D) about twenty times longer
E) longer than the age of the Galaxy
You would expect millisecond pulsars to be
A) part of a binary system.
B) isolated in space.
C) rotating slowly.
page-pf19
D) most common in open clusters.
E) collapsing rapidly.
Why are the designs of the Hubble and Chandra Space Telescopes different?
The planet ________ has the least variation in temperatures on the surface between day
and night.
What is the best time to see the corona? Why is it so faint, if it is so hot?
page-pf1a
Describe the range of sizes and masses of black holes.
Why do we believe there is dark matter?
Why doesn't the Hubble Space Telescope need adaptive optics?
page-pf1b
The twinkling of starlight and the focusing of images by lenses are both due to
________ of light.
Define shepherd moons and give an example of them at work.
Why do blue stragglers stand out in globular clusters?
page-pf1c
In composition, the ________ planets have rocky materials like the asteroids.
In the telescope, ________ shows the most turbulent atmosphere, with changes easily
seen even with amateur telescopes.
After reaching its peak luminosity in hours or days, a nova declines in brightness over a
period of a few ________ before returning to its pre-explosion luminosity.
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Why do we expect other solar systems to be common?
The common element with bright red, blue-green, and violet emission lines is
________.
Mercury's core is unusually ________, which may help explain its magnetic field.
As the average estimated lifetime of a technical civilization increases, then the distances
between neighboring civilizations would ________.

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