Astro Final
Which statement about the Sun's rotation is TRUE?
The Sun rotates at different rates at different latitudes on the Sun
Why does Mars have an overall reddish color when we see its surface from afar?
The material of Mars' surface contains a lot of iron oxide, the same chemistry that makes rusting metals look reddish
Which of the following statements about the Sun's photosphere is NOT TRUE?
The photosphere is significantly hotter than all the layers of the Sun beneath it (further inward)
At their centers, all the jovian planets have cores made of:
a solid mixture of rocky and icy materials under great pressure
Elements heavier than iron can be created during:
a supernova explosion
If there are at least a million asteroids, how did spacecraft like Galileo survive their trip through the asteroid belt?
although there are many asteroids, they are widely spaced (there is lots of space between them)
What type of main sequence star is most likely to become a black hole?
an O-type star
The orbit of a stable planet around a star like the Sun is always in the shape of:
an ellipse
Astronomers now know that surrounding the main body of our Galaxy (which our various kinds of telescopes have shown to us) and our fainter halo of stars there is
an invisible halo made of what astronomers are calling "dark matter"
Planets in the habitable zone of their stars:
are at a temperature where water can exist as a liquid
One of the key reasons that professional astronomers (as opposed to the public) are interested in comets is that they
are icy pieces left over from the time that our solar system formed that can give us clues about that early time
The smaller objects in the solar system made of rock and metal (most of which orbit between Jupiter and Mars) are called:
asteroids
Why were asteroids not discovered until the 19th century?
asteroids are generally small compared to planets and require a good telescope and patient searching to spot them
Which of the following statements about dark matter is FALSE:
astronomers have a pretty good idea what the dark matter is made of
If you could see the new moon, at what time of day (roughly) would it rise?
at sunrise
Astronomers have concluded that growing supermassive black holes (which have millions of times the Sun's mass or more) is pretty unlikely at our location in the Milky Way Galaxy. Where do they think is the most likely place in the Milky Way for such a supermassive black hole?
at the center of the Milky Way Galaxy, where matter is more crowded
From a city in the U.S., where in the sky would you look to see a star that is not turning with the motion of the sky in the course of a night?
at the north celestial pole
Where on Earth do stars always circle the zenith (and never rise and set)?
at the north pole
Solar wind particles can be captured by the Earth's magnetosphere. When these particles spiral down along the magnetic field into the atmosphere, they are responsible for:
aurorae (northern and southern lights)
Why is there a 4-minute difference between the solar day and the sidereal day?
because the Earth is going around the Sun in the course of a year
Why do telescopes have to have a good motorized drive system to move them smoothly?
because the Earth is rotating, with the telescope attached to it
Why are astronomers much more interested in the luminosity of a star than its apparent brightness?
because the luminosity tells us how much energy the star emits, while apparent brightness only tells us how bright it happens to look from Earth
Why do different types of atoms (elements) give off or absorb different spectral lines?
because the spacing of the energy levels is different in different atoms
Why did it take astronomers until 1838 to measure the parallax of the stars?
because the stars are so far away that their annual shift of position in the sky is too small to see without a good telescope
Why do astronomers prefer to put infrared telescopes on high-flying airplanes or on satellites in space?
because the water vapor in the lower atmosphere is very good at absorbing infrared
Why can a star with a mass like our Sun not fuse (produce) further elements beyond carbon and oxygen?
because they just cannot get hot enough for the fusion of heavier nuclei
Which color star is likely to be the hottest?
blue-violet
Astronomers estimate that the plains of Venus are only about 500 to 600 million years old. How do they estimate dates like this?
by counting the craters visible on the surface and comparing crater counts to other worlds
How did Eratosthenes measure the size of the Earth?
by measuring the height of the Sun in the sky on the same day in two cities at different latitudes
When Einstein proposed his General Theory of Relativity, he suggested some pretty strange ideas about space, time, and gravity. How did scientists in 1919 show that Einstein's theory described the behavior of the real world and wasn't just a crazy hypothesis?
by observing starlight coming close to the Sun during an eclipse
Really massive stars differ from stars with masses like the Sun in that they
can fuse elements beyond carbon and oxygen in their hot central regions
The latitude of the Earth's equator is
0 degrees
How far away would a star with a parallax of 0.2 arcsec be from us?
5 parsecs
The observation that began the 19th and early 20th century fascination with Mars as a place for life was:
Schiaparelli's seeing what seemed to him to be long straight features on the red planet
Why was the Kepler mission not able to find planets smaller than Mars, even though it was in space (and had no Earth atmosphere to deal with)?
Such planets make dips in the light of the star that are too small for Kepler to detect
The average temperature on planet Earth is higher than you would expect just from the heating of sunlight alone. What is the explanation for this?
carbon dioxide (and other gases) in the atmosphere cause a greenhouse effect
According to the general theory of relativity, the presence of mass
causes a curvature (or warping) of spacetime
If no one has ever visited the core of the Earth, how do we know that it is made of metals?
circulating liquid metals in the core set up a large (measurable) magnetic field
Which of the following statements about the different types (shapes) of galaxies is correct?
collisions and mergers between galaxies can sometimes change a galaxy's type (shape)
Why do galaxies collide, while stars almost never do?
compared to the size of a star, the stars are very far apart; but compared to the size of a galaxy, galaxies are close together
A new technique called adaptive optics allows astronomers to:
compensate for changes in the Earth's atmosphere and achieve better resolution
What objects did Harlow Shapley use as "signposts" to figure out the extent of the Milky Way Galaxy and the location of its center?
globular clusters
You are an astronomer who wants to study a faint star in the process of being born, which gives off most of its faint radiation in the infra-red. Which of the following would NOT be a step you would want to take?
heat your telescope, so its delicate optics are not cold
If stars with masses like our Sun's cannot make elements heavier than oxygen, where are heavier elements like silicon produced in the universe?
heavier elements are made in the cores of significantly more massive stars than the Sun, which can get hotter in the middle
When it comes to our place in the solar system today, which model do we accept?
heliocentric
Which of the following is evidence that the formation process of our Galaxy may have included collisions with smaller neighbor galaxies?
the observation of long moving streams of stars that continue to orbit through our Galaxy's halo
The celestial sphere turns once around each day because
the planet on which we live is rotating
In Ptolemy's system the planets orbit the Earth and not the Sun. How did the system explain the retrograde motion of planets like Mars?
the planets moved on a small circle whose center, in turn, circled a point near the Earth
On an H-R diagram of a cluster of stars, which characteristic of the diagram do astronomers use as a good indicator of the cluster's age?
the point on the main sequence where stars begin to "turn off" -- to move toward the red giant region
The process by which Venus became so much hotter than the Earth is called:
the runaway greenhouse effect
The reason type Ia supernovae are useful to astronomers for determining distances to other galaxies is that
they are very bright, and generally reach the same peak luminosity
What is one important way in which both the Moon and Mercury are different from Earth?
they do not have an atmosphere
Which of the jovian planets does NOT have any satellites?
you can't fool me, all the jovian planets are accompanied by satellites
Before you can use Hubble's Law to get the distance to a galaxy, what observation must you make of that galaxy?
you must take a spectrum of the galaxy and measure the red shift
What is the baseline that earth-bound astronomers use to measure the parallax (the distance) of the nearest stars?
½ the diameter of the Earth's orbit around the Sun
Where would you look for the youngest stars in the Milky Way Galaxy?
in the disk
The idea that objects (in the absence of an outside force) tend to continue doing what they are already doing is called the law of
inertia
You are alone in a large, completely dark auditorium on Earth. What kind of telescope should I use from the other side of the auditorium to detect the electromagnetic radiation emitted by your body?
infra-red
Which of the following is a way that the planet Mercury is similar to the Moon?
its surface is heavily cratered
Chunks of solid material that survive passing through the Earth's atmosphere and are found on the Earth's surface are called
meteorites
Earthquake producing faults are much more likely to be found
on the boundaries of continental plates, where they meet other plates
Where in the Sun does fusion of hydrogen occur?
only in the core
The canals that late 19th and early 20th observers thought they saw on Mars turned out to be:
optical illusions
The big surprise about the first planet discovered around another regular star was that it
orbited so close to its star it took only 4 days to go around
A white dwarf, compared to a main sequence star with the same mass, would always be:
smaller in diameter
Which of the following did NOT happen during the first few minutes after the Big Bang?
some very massive early stars formed
Our Milky Way Galaxy is what type of galaxy?
spiral
Why do astronauts float around in the Shuttle instead of falling?
the Shuttle is falling around the Earth (and everything aboard is in free fall)
The world in the solar system that is most active volcanically is:
Io
Why is an absorption spectrum especially useful for astronomers?
It has dark lines in it that allow astronomers to determine what elements are in the star
A planet in our solar system whose composition resembles that of our Sun is:
Jupiter
Which of the following is NOT a terrestrial planet?
Jupiter
Which of the following types of stars will spend the longest time (the greatest number of years) on the main sequence?
K
The largest volcano on Mars is called:
Olympus Mons (Mt. Olympus)
The large reservoir of comet nuclei far beyond Pluto, from which we believe new long-period comets come into the inner solar system, is called:
the Oort Cloud
In what fundamental way did the work of Galileo differ from his predecessors who had thought about the sky?
Galileo used instruments and experiments to show him what nature was doing, instead of relying on pure logic
The "prime meridian" (where longitude equals zero) passes through:
Greenwich, England
One of the great triumphs of spectroscopy was when astronomers identified a new element in the Sun (one that was only later found on Earth). Today, this element is called:
Helium
Mars appears to have long branching channels that have the appearance of being formed by a flowing liquid. Yet we know that liquids would not stay liquid in the very thin atmosphere we have on the Martian surface? So how can we explain the channels?
Mars had a thicker atmosphere long ago when the channels formed
The planet in our solar system with the shortest period of revolution is:
Mercury
The atmosphere of Venus is mostly carbon dioxide, and the atmosphere of the Earth has water vapor. Why are these two gases absent in the atmosphere of the satellite around Saturn called Titan?
Titan is so cold that carbon dioxide and water vapor freeze out
Which of the eight planets has a smaller mass than Mercury?
You can't fool me, Mercury has the smallest mass of the eight planets
Objects orbiting around the center of the Milky Way obey Kepler's 3rd Law. Therefore:
a cloud of gas or star that is further from the center will generally take more time to orbit
At first, right after the Big Bang, the universe was too hot for nuclei and electrons to combine into the kinds of neutral atoms that are familiar to us today. How soon after the beginning did it become cool enough for neutral atoms to form?
a few hundred thousand years
Newton showed that to change the direction in which an object is moving, one needs to apply:
a force
A type of star cluster that contains mostly very old stars is
a globular star cluster
The Orion Nebula is
a large cloud of gas and dust illuminated by the light of newly formed stars within it
How do astronomers know that there aren't significant amounts of dark matter within our solar system?
a lot of dark matter would affect the motions (orbits) of our spacecraft as the move through the solar system, and see no such effect
Which of the following, produced at the core of the Sun, will take the shortest time to emerge from the Sun's photosphere (surface)?
a neutrino
A Congressman from Texas visits our National Observatory in Tucson, Arizona, and wants to be shown an object in the universe with the "biggest darn redshift you ever saw". What type of object should the astronomers show him?
a quasar
What type of telescope can be used routinely on the surface of the Earth during the DAY?
a radio telescope
Which of the following is not an advantage that a reflector telescope has over a refractor telescope?
a reflector doesn't have to deal with the twinkling of the stars, as a refractor does
This chapter discusses that light sometimes acts like a photon. What is a photon?
a self-contained "packet" of electro-magnetic energy
A star moving toward the Sun will show:
a shift in the spectral lines toward the blue end (as compared to the laboratory positions of these lines)
From a particular location on Earth, why can we see many more total eclipses of the Moon than total eclipses of the Sun?
a total lunar eclipse is visible over a much larger part of the Earth's surface than a total solar eclipse
The asteroid belt is
a zone where rocky chunks orbit between Mars and Jupiter
Factoring in everything we currently know about the history of the universe, our best estimate for the age of the universe is
about 13.8 billion years
The Red Spot of Jupiter is:
all of these
Which of the following is evidence for volcanic activity on Venus?
all of these
Which of the following is NOT a correct statement about the ways the jovian planets differ from the terrestrial planets?
all the jovians have satellites around them and none of the terrestrials do
In the very distant future, given our best model of the accelerating universe, what will the universe look like?
all the stars will die and the galaxies will be dark
The event in the life of a star that begins its expansion into a giant is
almost all the hydrogen in its core that was hot enough for fusion has been turned into helium
In an H-R diagram, where can you see the spectral type of a star (whether it is an O type star or a G type star, for example)?
along the bottom (the horizontal axis)
According to Kepler's third law, there is a relationship between the time a planet takes to revolve around the Sun and its
distance from the Sun
Which type of galaxy is observed to contain mostly older stars?
elliptical
If you are in a freely falling elevator near the top of a tall building, as the elevator falls, your weight would be:
equal to zero - you would be weightless
Where in space did the expansion of the universe begin?
everywhere at once
According to Kepler's 2nd Law, comets (which have eccentric orbits) should spend a lot more of their time:
far from the Sun
An astronomer needs to measure the distance to a globular cluster of stars that is part of a neighboring galaxy nearby the Milky Way Galaxy. What method should she try to use to find the distance?
find a variable star (cepheid or RR Lyrae) in the cluster
One of the main projects being carried out by the Hubble Space Telescope is to measure the distances of galaxies located in groups dozens of millions of lightyears away. What method do astronomers use with the Hubble to find such distances?
finding Cepheid variables and measuring their periods
What method would astronomers use to find the distance to a galaxy so far away that individual stars are impossible to make out (resolve)?
finding the redshift and using Hubble's Law
When one member of a binary star system is a black hole, and astronomers detect flickering x-rays coming from the system, where are these x-rays usually coming from?
from a disk of material around the black hole (material that has been pulled from the companion star and is falling toward the black hole)
Astronomers have noticed that the visible filaments in the Crab Nebula are moving toward us at great speed. How can they know about motions like this?
from the Doppler shift in the line radiation from the nebula
Astronomers believe that the large elliptical galaxies formed
from the collision and merger of many smaller fragments
What phase of the Moon must it be to have a lunar eclipse?
full moon
Astronomers identify the main sequence on the H-R diagram with what activity in the course of a star's life?
fusing hydrogen into helium in their cores
One of the most perplexing issues raised by the discovery of thousands of exoplanets is the existence of "hot Jupiters" - planets with the masses and compositions of Jupiter, but orbiting closer to their stars than Mercury does in our solar system. What is our best idea currently about how such "hot Jupiters" came to be?
hot Jupiters formed further out in their star system, and then migrated inward somehow
If you were to take a large sample of the four giant planets, the most common element you would find in them is:
hydrogen
The element that can act like a metal when it is under tremendous pressure and is probably responsible for Jupiter and Saturn's magnetism is:
hydrogen
The most common element in the Sun is
hydrogen
A star with a mass like the Sun which will soon die is observed to be surrounded by a large amount of dust and gas -- all material it has expelled in the late stages of its life. If astronomers want to observe the radiation from such a giant star surrounded by its own debris, which of the following bands of the spectrum would be the best to use to observe it?
infrared
The most stable (tightly bound) atomic nucleus in the universe is:
iron
Two versions of an element with different numbers of neutrons are called:
isotopes
Using a good pair of binoculars, you observe a section of the sky where there are stars of many different apparent brightnesses. You find one star that appears especially dim. This star looks dim because it is:
it could be any of these; there is no way to tell which answer is right by just looking at the star
Astronomers believe that Mars formed with a much thicker atmosphere than it has today. Where did this atmosphere go?
it escaped into space (and some later froze out as Mars got cold)
Measurements show a certain star has a very high luminosity (100,000 x the Sun's) while its temperature is quite cool (3500oK). How can this be?
it must be quite large in size
What was especially noteworthy about the Sagittarius Dwarf Galaxy when it was discovered among the small galaxies near the Milky Way?
it was on a collision course with the Milky Way and would be swallowed by it eventually
When the James Webb Space Telescope is finally launched, what will be its distinguishing characteristic (what about it will really help astronomers)?
it will have the largest mirror ever put into space for observing faint objects
The closest star to the Sun, Proxima Centauri, was recently found to have a planet in its habitable zone. Proxima Centauri is a main sequence star with spectral type M. How would its habitable zone differ from the habitable zone of our Sun?
it would be significantly closer to Proxima Centauri than ours is to the Sun
In general, the further planets are from the Sun, the cooler they are. What other factor can have a significant influence on a planet's surface temperature?
its atmosphere (whether it has one and how thick it is)
Astronomers must often know the distance to a star before they can fully understand its characteristics. Which of the following properties of a star typically requires a knowledge of distance before it can be determined?
its luminosity
When a star settles down to a stable existence as a main-sequence star, what characteristics determines where on the main sequence in an H-R diagram the star will fall?
its mass
In a bad late-night science fiction film, a villain is using a large collection of rare radioactive atoms as energy for a weapon to threaten the good guys. The atoms have a half-life of 1 hour. The villain has 4 kilograms of the radioactive material now, and he needs a minimum of 1 kg. for his weapon to work. After how much time will the weapon no longer be a threat?
just a little after 2 hrs
We have two waves of light, A and B. Wave A has a higher frequency than wave B. Then wave B must have:
longer wavelength
The most common kinds of stars in the Galaxy have
low luminosity compared to the Sun
To predict whether a star will ultimately become a black hole, what is the key property of the star we should look at?
mass
What technique did astronomers use to make the first confirmed discovery of a planet around another star like the Sun?
measure the Doppler shift of the lines in the star's spectrum and look for periodic changes in this shift due to the pull of the planet as it orbits the star
The first technique that allowed astronomers to find exoplanets involved:
measuring changes in the radial velocity (Doppler shift) of the star caused by the pull of orbiting planets
The Global Oscillations Network Group (GONG) Project is engaged in:
measuring the pulsations of the Sun from stations around the world
According to the geocentric view, everything in the heavens had to go around the Earth, which was the center of the universe. What objects did Galileo discover with his telescope that clearly didn't go around the Earth?
moons around the planet Jupiter
How are globular clusters distributed in our Milky Way Galaxy?
mostly in a large spherical halo (or cloud) surrounding the flat disk of the Galaxy
When a planet, in its orbit, is closer to the Sun, it:
moves faster than average
Two stars have the same luminosity, but star B is three times farther away from us than star A. Compared to star A, star B will look
nine times fainter
Today we realize that the source of energy for the Sun is a process called
nuclear fusion
A graduate student in astronomy needs to measure the mass of a spiral galaxy she is studying for her PhD thesis. Which of the following observations would be important for her to make?
obtain the speed at which stars or gas near the outer regions of the galaxy are moving around
A very rich, very shady international banker (with residences all over the globe, including Newark, New Jersey) mysteriously disappears. Someone later mails a wide-angle photo of his body to a London newspaper, taken on June 22, showing the Sun exactly overhead at noon. What can the police deduce from this photograph about where on Earth the body is located?
on the Tropic of Cancer (23N)
Callisto, the fourth moon of Jupiter's, takes 17 days to orbit Jupiter. If I stand on the surface of Callisto and see Jupiter high in the sky over my head, and then wait 8.5 Earth days in the same spot, where will I see Jupiter?
overhead, where it was before
When a comet comes closest to the Sun in its orbit, we say that it is at:
perihelion
An astronomer is interested in a galaxy called M31, the nearest galaxy that resembles our Milky Way. It is about 2 million light-years away. Which technique would be able to give us a distance to this galaxy?
period-luminosity relation for Cepheid variables
How are galaxies and quasars related?
quasars are active supermassive black holes at the centers of galaxies
Which of the following has the longest wavelength?
radio waves
When a planet temporarily moves westward in the sky over the course of several weeks or months (instead of eastward, as it typically does), we call it:
retrograde motion
All the planets (without exception)
revolve around the Sun in the same direction
According to the theory of plate tectonics
slow motions within the mantle of the Earth move large sections of the crust around
Astronomers observe a young cluster of stars, where stars with three times the mass of the Sun are still on the main sequence of the H-R diagram. Yet the cluster contains two white dwarfs, each with a mass less than 1.4 times the mass of the Sun. If we can show that the white dwarfs are definitely part of the cluster, how can their presence so soon in the life of the cluster be explained?
stars lose a lot of mass on their way to becoming white dwarfs; and so the white dwarfs could have started out as quite massive stars
How do fragile structures like acetaldehyde (CH3CHO) molecules survive in the harsh environment of interstellar space? Why are they not destroyed by high-energy radiation from stars?
such molecules are found only in dense clouds that have a lot of dust; the dust keeps the radiation from hot stars from reaching the molecules
A "New Age" bride and groom, who are enchanted by the Sun, want to get married on the day when it gets to be highest in the sky. If they live in the United States, around what day of the year will the wedding take place?
summer solstice
Astronomical observatories have been available since ancient times, and many cultures set aside special sites for astronomical observations. The thing modern observatories have that was missing from these older observatories until about 1610 was:
telescopes
The new instrument that made it possible for Edwin Hubble to demonstrate the existence of other galaxies in the early 1920's was:
the 100-inch reflector on Mount Wilson
Which of the following is pretty good evidence that the universe began with a Big Bang?
the 3-degree cosmic microwave background radiation
In its overall composition, the Moon roughly resembles:
the Earth's crust and mantle
Which of the following is NOT part of the growing chain of evidence that makes many astronomers suspect there is a black hole at the very center of the Milky Way Galaxy?
the Hubble Space Telescope has shown us a visible-light image of an accretion disk at the center of the Galaxy
The telescope that allowed astronomers to discover most of the planets found with the transit method was called
the Kepler mission
Our modern understanding of Pluto is that it is a member of
the Kuiper Belt (of trans-Neptunian objects)
Which of the following does the composition of a planet like Jupiter resemble:
the Sun
Why does the Moon show phases in the course of a month?
the angle the Moon makes with the Sun changes and we see differing amounts of reflected sunlight
We observe a glowing cloud of gas in space with a spectroscope. We note that many of the familiar lines of hydrogen that we know on Earth seem to be in a different place. They are shifted toward the blue or violet end of the spectrum compared to their positions in the spectrum of glowing hydrogen gas on Earth.
the cloud is moving toward us
When a star first begins the long path toward becoming a red giant, a layer of hydrogen around the core begins to undergo fusion. If this layer was too cold to do fusion throughout the main sequence stage, why is it suddenly warm enough?
the core is collapsing under its own weight and heating up from the compression; this heats the next layer up
According to the most recent data from satellites making precise measurements of the properties of the cosmic background radiation (CBR),
the dark energy makes up just a little less than 70% of the density of the universe, making it the most significant constituent of the mass-energy
If observations of supernovae in other galaxies show that such an explosion happens in a spiral galaxy like the Milky Way on average every 25 to 100 years, why have astronomers on Earth not seen a supernova explosion in our Galaxy since 1604?
the disk of our Galaxy contains a great deal of dust, which tends to block the light of supernova explosions from more distant parts of our Galaxy
What observations about disks of dusty material around young stars suggest that planets may be forming in such disks?
the disks show lanes that are empty of dust within them
William Herschel thought that the Sun and Earth were roughly at the center of the great grouping of stars we call the Milky Way. Today we know this is not the case. What was a key reason that Herschel did not realize our true position in the Milky Way?
the dust that extends throughout the disk of the Galaxy only allowed Herschel to see the small part of the Milky Way that surrounds us
Scientists now understand that the Earth consists of layers, with the densest materials in the core. What allowed the differentiation of the Earth's layers to happen?
the early Earth must have been so hot it was like a liquid and heavier things sank to the middle
A friend of yours who is a science fiction fan hears you talk about the fact that astronomers now believe that the mechanism for the large energy output of quasars involves a supermassive black hole. He challenges you, saying something like "Oh come on, every science fiction fan knows that nothing, not even light, can escape from a black hole! How can a black hole be an energy source?" How would you respond to his objection?
the energy we see from quasars comes from regions where matter is falling in; these regions are still outside the event horizon
Astronomers have measured that there is more helium in the universe than can be explained by the fusion in stars over the last 13 billion years. How do they think the extra helium got into the universe?
the extra helium was made during the first few minutes of the Big Bang, when the entire universe was hot enough for fusion to occur briefly
Edwin Hubble was able to show that (with the exception of our nearest neighbors) the farther a galaxy is from us, the
the faster it is moving away from us
If we look back to the first generation of stars made when the Galaxy was first forming, how do they differ from stars being formed today?
the first generation stars contain little or no elements heavier than helium
In the four terrestrial planets, the densest, heaviest materials are at the center and not evenly distributed throughout the planet. Scientists interpret this observation to mean that:
the four terrestrial planets must once have been hot enough to be molten (like a liquid)
With enormous effort, a team of astronomers manages to collect enough light from a galaxy far, far away to produce a spectrum. That spectrum has lines from the elements carbon, silicon, and sulfur. This tells the team that
the galaxy must have had an entire generation of stars that was born, lived, and died
Which of the following is the Earth not located in?
the globular cluster M-13
Comets change as they approach the Sun in their orbits. Which of the following statements about a comet approaching the Sun is FALSE?
the gravity of the comet nucleus holds on to the evaporated material, and it all eventually freezes back into the nucleus
You are observing a binary star system and obtain a series of spectra of the light from the two stars. In this spectrum, most of the absorption lines shift back and forth as expected from the Doppler Effect. A few lines, however, do not shift at all, but remain at the same wavelength. How can we explain the behavior of the non-shifting lines?
the lines come from interstellar matter between us and the star, not from the stars themselves
Among interstellar clouds, the hotter the cloud, the
the lower the density of particles in it
In the first direct detection of gravitational waves by LIGO in 2015, the waves came from
the merger of two black holes
In the far future, a starship becomes trapped inside the event horizon of a black hole. Although the crew discovers that their ship cannot out, they at least want to send a message to other ships in the area to stay away from the danger zone. If they send out a message in the form of a radio wave, what will be its fate?
the message will never emerge from the event horizon
The U.S. has plans to build a 30-meter telescope, while the Europeans are thinking about 39-meter telescope. What technological innovation allows astronomers to be thinking about telescopes with that large an aperture?
the mirror in these telescopes will be constructed from many smaller mirrors which will work together
A college friend of yours who has been postponing taking any science courses hears you talking about the generation of nuclear energy in the Sun and makes the following observation: "The whole idea of the atomic nucleus is pretty ridiculous. If an oxygen nucleus consists of eight protons and eight neutrons, the charge on that nucleus is positive. Since even I learned in high school that like charges repel, such a nucleus would find all its positive protons repelling and quickly fall apart." How would you answer his argument?
the nuclear force, which is attractive over short distances like the nucleus, and stronger than electricity, holds the nucleus together
A neutron star is as dense as
the nucleus of an atom
The first time that astronomers observed both gravitational waves and electro-magnetic waves from the same event, what they were observing was:
the spiraling toward each other of two neutron stars
When a star undergoes a nova explosion, it may return to its "quiet state" and later become a nova again. What would allow a nova explosion to happen to a star more than once?
the star that goes nova has a companion star near it, which dumps material onto the first star and continues to do so even after the first nova explosion
What would you have to change about the Earth to stop our planet from having significantly different seasons?
the tilt of its axis
Let's say we find a star that is located on the points or circles in the sky listed in the answer choices below. Then, on the same night, we move to a location on Earth that is some significant distance from our first location. There will now be a different star at or on:
the zenith
Which of the following is NOT one of the key reasons that so many spacecraft from Earth have visited Venus and Mars?
their atmospheres are very similar to the Earth in terms of their chemical make-up
If quasars often resemble little blue stars, what was it about them that so surprised astronomers when they were discovered?
their spectral lines were at first hard to recognize and then turned out to have large redshifts
What makes astronomers think that impact rates for the Moon must have been higher earlier than 3.8 billion years ago?
there are ten times more craters on the older highlands than the younger maria
Most of the really bright stars in our sky are NOT among the stars that are very close to us. Why then do they look so bright to us?
these stars are intrinsically so luminous that they can easily be seen even across great distances
Which of the following characteristics do all four terrestrial planets have in common?
they all have solid surfaces with signs of geological activity on them
Among irregular galaxies, what makes the Large and Small Magellanic Cloud especially useful for astronomers?
they are (for galaxies) very close to us, so they are easy to study
How do astronomers know how strong the magnetic field of the Sun is?
they measure the Zeeman effect (the splitting of spectral lines)
Among solid worlds, which type of world is most likely to have significant geological activity?
those that are the largest (and retain heat the best)
The dust in the dust clouds in interstellar space consists of
tiny solid grains
One important way astronomers can learn in some detail about what happens when galaxies collide is
to simulate galaxy collisions on a large computer and watch what the simulation predicts
A star whose temperature is increasing but whose luminosity is roughly constant moves in what direction on the H-R diagram?
to the left
After several decades of observation, astronomers have concluded that quasars are
very powerful and compact sources of energy at the centers of distant galaxies
Some of the interstellar gas in our Galaxy has been heated to millions of degrees, a temperature that surprised astronomers when it was first discovered. How do we now think that gas between stars gets that hot?
very powerful shock waves from exploding stars heat the gas they come into contact with
If you were to scale up an atom until it were the size of a sports arena, the space filled by the positive charges inside the atom (according to the work of Ernest Rutherford early in this century) would be:
very small (perhaps the size of a soccer ball) and in the middle
What is the most important reason that astronomers have learned more about our planetary system in the last 30-40 years than all of history before then.
we have been able to send spacecraft to gather information about planets and moons up close
What evidence can you give that shows the surface of Jupiter's moon Europa must be relatively young?
we see very few craters compared to the surfaces of Callisto and Ganymede
When a single star with a mass equal to the Sun dies, it will become a
white dwarf
Which of the following types of telescopes can be used ONLY above the Earth's atmosphere?
x-ray telescope
