Ch. 24,25,26,29

Why did Einstein introduce the cosmological constant into the equations of his General Theory of Relativity when describing the universe? a. Einstein did not realize that black holes would exist at the centers of galaxies and pull everything into them b. Einstein's equations required the universe to expand or contract; he could not imagine or accept it doing either one, so he put a factor in to stop it from moving c. Einstein talked to Hubble and learned about Hubble's observations of the expanding universe, which made him so uncomfortable that he decided to change his equations d. Einstein had a hunch that the universe was accelerating (speeding up its expansion) back in 1918 and so introduced the constant into his equations to describe that e. Einstein liked cups of tea in the afternoon, and his constant was a comment on that habit

Einstein's equations required the universe to expand or contract; he could not imagine or accept it doing either one, so he put a factor in to stop it from moving

the scientist who made the first telescopic survey of the Milky Way and discovered that it is composed of a huge number of individual stars was

Galileo Galilei

The astronomer who first worked out the mathematical description of black hole event horizons was a. Edwin Hubble b. Jocelyn Bell c. Karl Schwarzschild d. S. Chandrasekhar e. Frederik Pohl

Karl Schwarzschild

The first scientist to propose a specific model (the primeval atom model) for the big bang was a. Lemaitre b. Hubble c. Sandage d. Peebles e. Nobel

Lemaitre

Your weird cousin, who is really into astronomy, decides that the return address he uses on his letters is incomplete! To his city, state, and country, he begins to add: "North America, Earth, Solar System..." If he now wants to include the name of the Galaxy's spiral-structure feature in which the Earth is located, how should his address end? a. Cygnus Arm b. Orion Spur c. Perseus Arm d. Sagittarius-Carina Arm e. Mars arm

Orion Spur

Milky Way Galaxy Type?

Spiral

The standard bulbs (standard candles) that made it possible for astronomers to discover the acceleration in the expansion of the universe were a. globular clusters b. Cepheid variable stars c. the brightest irregular galaxy in a rich cluster d. Type Ia supernovae e. the size of a galaxy dark matter halo

Type la supernova

Astronomers today know a lot about the size and shape of the Milky Way Galaxy. Which of the following common objects most resembles the shape of our Galaxy? a. a beach ball b. a flag, fluttering in the breeze c. a CD or DVD d. a cake e. a glazed donut

a CD or DVD

About two thirds of the nearby spiral galaxies (which we can study in more detail) don't have a round central bulge, but instead show a. no central bulge at all, just a uniform galaxy b. a central bulge with a bar of stars in the middle c. a central bulge with a completely irregular and unsymmetric shape d. a central bulge with 2 giant jets coming out larger than the galaxy e. you can't fool me; all spirals have a round central bulge

a central bulge with a bar of stars in the middle

The central region of our Galaxy is not as flat as its main disk of stars. Which of the following has roughly the same shape as our central region of stars? a. a peanut b. a tennis ball c. a cube d. a long piece of string e. actually, no one knows the shape of our central region because of all the dust in the Galaxy

a peanut

You suddenly get an uncontrollable urge to find out more about the other side of the Milky Way Galaxy (the regions beyond the center). Where should you rush off to? a. the control room of the Hubble Space Telescope at NASA b. a radio telescope that can observe at 21-cm wavelengths c. the control room of the Compton Gamma-Ray Observatory d. a gold mine near Lead, South Dakota e. the same factory that makes Snickers candy bars

a radio telescope that can observe at 21-cm wavelengths

Deep inside a black hole (and hidden from our view) is the compressed center, where all the "stuff" of the star goes. Astronomer call this central point a. an event horizon b. a singularity c. a time-stopping point d. a black dwarf e. Bayonne, New Jersey

a singularity

Factoring in everything we currently know about the history of the universe, our best estimate for the age of the universe is a. 4.6 billion years b. about 100 billion years c. roughly 2 million years d. about 13.8 billion years e. the age of the universe is infinite; there was no beginning

about 13.8 billion years

Suppose each of the following objects could collapse into a black hole. Each black hole would have a sphere around it that is the limit for escape -- once you are inside this region, you cannot get away. For which object would this region be the largest in diameter? a. a star with the mass of our Sun b. a planet like Jupiter c. a star that was type O when it was on the main sequence d. an entire cluster of stars (with about 150 stars in it) e. an entire galaxy of stars (with about a billion stars in it)

an entire galaxy of stars (with about a billion stars in it)

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 a. only the empty space that lies between galaxies b. a series of hundreds and hundreds of nearby small galaxies, held in place by the Milky Way's gravity c. an invisible halo made of what astronomers are calling "dark matter" d. a set of huge clouds with many interesting molecules (like alcohol, carbon monoxide, and ammonia) in them e. a pair of long, bright jets of materials produced by a massive black hole and its accretion disk

an invisible halo made of what astronomers are calling "dark matter"

Which of the following statements about the early universe (as envisioned by the standard model of cosmology) is FALSE? a. as the universe expands, its temperature decreases b. at the beginning, the temperature was hot enough to turn energy into matter c. at the very beginning, the energies were so great that the universe was actually contracting for a while d. at the beginning, the universe was not transparent to electro-magnetic radiation e. at the very beginning, anti-matter (as well as matter) was present in significant quantities

at the very beginning, the energies were so great that the universe was actually contracting for a while

Today, we believe that only a small number of elements were actually formed during the Big Bang. Which of the following was NOT one of these: a. hydrogen b. carbon c. lithium d. helium e. you can't fool me, all of the above were definitely formed during the big bang

carbon

Which of the following statements about the different types (shapes) of galaxies is correct? a. whatever type a galaxy is at its birth, that's what it will be for all time b. all galaxies start out as ellipticals, but some later evolve to be spirals and irregulars c. 90% of all galaxies are spirals (including our Milky Way); the other two types are very unusual d. collisions and mergers between galaxies can sometimes change a galaxy's type (shape) e. what type we see a galaxy to be just depends on the angle at which we happen to see it; all galaxies look roughly the same in shape

collisions and mergers between galaxies can sometimes change a galaxy's type (shape)

Which type of galaxy is very difficult to see, but (astronomers recently realized) may be very common? a. spiral b. elliptical c. dwarf elliptical d. irregular e. none of the above

dwarf elliptical

Which of the following is the Earth not located in? a. the solar system b. the universe c. globular cluster M-13 d. the Milky Way Galaxy e. the Earth is located in all of the above

globular cluster M-13

What objects did Harlow Shapley use as "signposts" to figure out the extent of the Milky Way Galaxy and the location of its center? a. thick clouds of cold hydrogen giving off 21-cm radiation b. globular clusters c. HII regions d. dust clouds e. big arches advertising "billions and billions sold"

globular clusters

What have we learned from the work of Harlow Shapley and others about the location of the Sun in the Milky Way Galaxy? a. we are almost exactly in the center of a giant flat pinwheel b. we are very close the edge of the visible disk of the Galaxy, more than 50,000 LY from the center c. we are high above the disk of the Galaxy, about as far away as the most distant globular cluster d. we are in the disk of the Galaxy, about 3/5 of the way from the center e. you can't fool me; because of all the dust, astronomers still have no idea where our Sun is located in the Milky Way Galaxy

we are in the disk of the Galaxy, about 3/5 of the way from the center

If we include the effects of deceleration in our calculations of the age of the universe, the age we get is: a. greater than the Hubble time b. less than the Hubble time c. equal to the Hubble time d. either greater or less depending on the amount of deceleration e. you can't fool me; this question cannot be answered without knowing the exact value of the Hubble constant.

less than Hubble time

Which of the following is NOT a characteristic of a spiral galaxy? a. most of its material is in the shape of a flattened disk b. it has quite a bit of gas and dust in it c. it has young stars and bright emission nebulae d. when we take spectra of its stars, they have far less of the heavier elements than the Sun e. the bright stars in it can be seen organized into distinct spiral arms

when we take spectra of its stars, they have far less of the heavier elements than the Sun

Which of the following can a black hole not "eat" (swallow)? a. a planet b. a cloud of gas and dust c. a star d. another black hole e. you can't fool me, black holes can eat anything

you can't fool me, black holes can eat anything

To predict whether a star will ultimately become a black hole, what is the key property of the star we should look at? a. mass b. surface temperature c. color d. distance e. diameter

mass

When do astronomers now think that the "dark energy" began to accelerate the expansion of the universe? a. right after the Big Bang (after the first three minutes or so) b. a few million years after the Big Bang c. several billion years after the Big Bang d. about ten million years ago e. when the city of Bayonne, New Jersey was founded

several billion years after the Big Bang

Which of the following did NOT happen during the first few minutes after the Big Bang? a. temperatures throughout the universe were hotter than the cores of stars are today b. two or three of the simplest elements fused together c. energy was converted to matter d. some very massive early stars formed e. matter and antimatter collided and turned into energy

some very massive early stars formed

The type of galaxy that sometimes has a distinct bar of stars running across the central region is a. spiral b. elliptical c. dwarf elliptical d. irregular e. all of the above can have clear, distinct central bars

spiral

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? a. the message will emerge from the event horizon with a huge gravitational redshift b. although the radio wave will emerge from the event horizon, all the information in the message will be garbled c. the radio wave will become a gamma ray by the time it emerges from the event horizon d. the radio wave will only emerge from the event horizon if it is moving in the direction of the magnetic north and south pole of the star that formed the black hole e. the message will never emerge from the event horizon

the message will never emerge from the event horizon

Edwin Hubble developed a classification scheme for galaxies. By what characteristic did he classify galaxies? a. their brightness b. their overall color c. their shape d. their abundance of the element iron e. their Doppler Shift

their shape

Among irregular galaxies, what makes the Large and Small Magellanic Cloud especially useful for astronomers? a. they are (for galaxies) very close to us, so they are easy to study b. they are among the biggest irregular galaxies ever found c. they have a regular shape, but it is so complicated it was hard to figure out d. they do not contain any young stars at all, only really old ones e. their shape resembles a map of Bayonne, New Jersey

they are (for galaxies) very close to us, so they are easy to study

One of the most important observations in the history of astronomy was the one by Edwin Hubble that established that there are other galaxies, quite removed from the Milky Way. How did Hubble show this? a. by debating with Harlow Shapley and being more eloquent b. by observing a supernova explosion in a nearby galaxy, using it as a "standard bulb" c. by observing a Cepheid variable in a nearby galaxy and using it to get the distance d. by measuring the distances to many globular clusters using parallax e. by going to see Einstein, who knew the answers to these kinds of questions

by observing a Cepheid variable in a nearby galaxy and using it to get the distance

The type of galaxy that consists almost entirely of old stars and is thus less blue (more yellow and reddish) than the other types is: a. spiral b. elliptical c. irregular d. barred spiral e. all of the above consist almost entirely of old stars

elliptical

Which type of galaxy is observed to contain mostly older stars?

elliptical

An astronomer needs to measure the distance to a globular cluster of stars that is part of the Milky Way Galaxy. What method should she try to use to find the distance? a. measure the parallax of the cluster b. count the number of O and B type stars in the cluster c. look for flickering x-rays coming from a black hole in a binary star system in the cluster d. measure the red-shift of the cluster e. find a variable star (cepheid or RR Lyrae) in the cluster

find a variable star (cepheid or RR Lyrae) in the cluster

A handsome, rich, but vain movie star notices that he is starting to age, and consults you as his astronomy expert, to see if you can find an astronomical way to slow down his aging. Putting aside practical considerations (such as the fact that we cannot travel to other stars), which of the following strategies would IN THEORY allow him to age more slowly than the rest of humanity. a. he should always live at sea level on Earth, and never go to any mountains or high altitudes b. he should live far away from the gravity of any planet or star (in a deep-space station) c. he should be in orbit around the Earth, and expose himself to as many cosmic rays as possible d. he should travel to a black hole, and spend some time in orbit just above the event horizon e. he should live in a room filled with positive electrical charge

he should travel to a black hole, and spend some time in orbit just above the event horizon

Radio astronomy has played a pivotal role in showing us the detailed structure of the Milky Way Galaxy. Which of the following techniques would a radio astronomer use as an essential part of an investigation of this structure? a. measuring the Doppler shift of a line in a radio spectrum b. taking a photograph of the sky in the direction of the Big Dipper c. using a CCD and a filter to record the amount of light from the stars in a nearby open cluster d. measuring the amount of synchrotron radiation from the Crab Nebula e. measuring the amount of radio radiation coming from the direction of Jupiter and other planets in the solar system

measuring the Doppler shift of a line in a radio spectrum

Wearing a very accurate watch, you volunteer to go on a mission to a black hole in a spaceship that has powerful rockets. You are able to orbit the black hole and stay a little distance outside of the event horizon. Compared to watches on Earth, your watch near the black hole will run: a. more slowly b. more quickly c. infinitely slow d. infinitely fast e. you can't fool me, watches near a black hole don't change the pace at which they run

more slowly

At about 1 second after the beginning of the universe, one type of particle was able to start traveling freely through the universe. These particles are still with us, but they are extremely hard to detect. They are called: a. photons b. protons c. electrons d. neutrinos e. college presidents

neutrinos

What type of main sequence star is most likely to become a black hole? a. an O-type star b. a G-type star c. a K-type star d. an M-type star e. you can't fool me, all spectral types on the main sequence have an equal chance of becoming black holes

o-type star

When scientists say that "black holes have no hair", what do they mean? a. that the event horizon of a black hole is very smooth and does not have parts that jut out b. that if you threw something toward a black hole (a rabbit, say) it would quickly be ripped apart into smaller pieces c. that time near a black hole slows down so much our hair would not grow at a normal rate d. that once a black hole forms, very little information can be extracted from it about the material that is now inside e. no one knows what this means; regular people are not meant to figure out some of the weird things physicists say about black holes

that once a black hole forms, very little information can be extracted from it about the material that is now inside

When we determine the age of the universe using the Hubble Time, what important simplifying assumption goes into our calculations? a. that the expansion of the universe has been happening at the same rate - neither speeding up or slowing down b. that all the galaxies are moving away from us at exactly the same speed, no matter how far away they are c. that the cosmological principle doesn't hold: the universe is not isotropic and homogeneous d. that we have accounted correctly for the effects of dark energy e. that the universe is actually contracting instead of expanding

that the expansion of the universe has been happening at the same rate - neither speeding up or slowing down

The new instrument that made it possible for Edwin Hubble to demonstrate the existence of other galaxies in the early 1920's was: a. the Hubble Space Telescope (that's why we named it after Hubble!) b. the 300-ft radio telescope in West Virginia c. a kind of electronic detector called a CCD d. the 100-inch reflector on Mount Wilson e. an infra-red telescope carried aboard one of the early airplane flights by the Wright Brothers

the 100-inch reflector on Mount Wilson

The reciprocal of the Hubble constant (1/H) is a rough measure of the: a. the period of a typical Cepheid variable b. the distance to the last galaxies that formed c. the age of the universe d. the luminosity of a type I supernova explosion e. the cost of building a telescope in space

the age of the universe

Which of the following statements about the nuclear bulge of our Galaxy is FALSE? a. it is significantly thicker than the disk of the Galaxy b. it typically consists of older stars c. it is difficult for us to see with visible light because of cosmic dust d. the best way to learn more about it is to observe higher energy radiation, such as ultraviolet and x-rays e. there is evidence that it is not exactly spherical, but elongated

the best way to learn more about it is to observe higher energy radiation, such as ultraviolet and x-rays

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? a. he did not have a telescope, and most stars are too far away to see without a telescope b. his telescope was only able to show him objects inside the solar system, and not objects in the Galaxy c. 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 d. there are so many black holes in the Galaxy, that they absorb a substantial part of the light from distant objects; we needed x-ray astronomy to see to more distant regions e. Herschel shared with ancient people the firm religious belief that we must be the center of everything

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

The region around a black hole where everything is trapped, and nothing can get out to interact with the rest of the universe, is called a. the singularity b. the neutron star radius c. the gravitational redshift zone d. the event horizon e. day-time television

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? a. the extra helium was produced in the accretion disks of supermassive black holes b. 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 c. the extra helium was produced by the interaction of dark matter with the material at the edges of all galaxies d. the extra helium was produced recently during Type Ia supernova explosions e. the idea that there is extra helium has been shown to be in error; we were confused by the high redshifts of distant galaxies distorting their spectra

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

Once a black hole forms, the size of its event horizon is determined only by a. the size (diameter) of the star that collapsed into the black hole b. the mass inside the event horizon c. the time since the black hole formed d. the composition of the material that formed the black hole e. you can't fool me; every black hole has an event horizon of the same size

the mass inside the event horizon