Astronomy Ch. 14 Practice Test

The center of the Milky-Way lies in the direction of the constellation Cygnus.

The Milky Way is simiar in many ways to M31, the Andromeda Galaxy.

Our Sun lies about 30,000 light years out from the Galactic Center.

The Earth lies close to the center of the Galaxy.

The longer the period of pulsation for a Cepheid, the more massive and luminous the variable giant star is.

Because of their greater luminosity, RR Lyrae stars can be used at greater distances than can long-period Cepheids.

William Herschel's original model for our Galaxy was based on counting stars.

Herschel's original disk model placed us close to the center of the Galaxy.

Shapley's measurements of the distances to open clusters vastly revised our understanding of our position in the Galaxy.

All Cepheids are giants, but not all giant stars are Cepheid variables.

Shapley found the globular cluster distribution equally concentrated all along the galactic plane.

Shapley found that globular clusters are only found in the Galactic bulge.

The problem with visual observations of our Galaxy is the luminous gas haze.

William Herschel made the first map of the Galaxy about 200 years ago.

The instability strip is above the main sequence on the H-R diagram.

RR Lyrae stars pulsate, but with shorter periods and lower luminosities than Cepheids.

The instability strip shows that not all main-sequence stars are, in face, stable.

It is harder to map the structure of the Milky Way in visible wavelengths than the radio and infrared waves.

All RR Lyrae stars are about 5 times the Sun's luminosity.

All Cepheid variables discovered so far lie in other galaxies.

Like the RR Lyrae stars, Cepheids are all similar in luminosity, hence their use in measuring stellar distances.

Herschel believed teh Milky Way was a disk of stars, while Shapley found teh extended halo more like a ball.

Shapley found the globular clusters were strongly concentrated toward Sagittarius.

Harlow Shapley mapped the Milky Way using the period-luminosity relationship for RR Lyrae stars.

21 cm radio waves allow us to map the distribution of hydrogen in spiral arms on the opposite side of the Galaxy.

Population I stars came billions of years before Population II stars.

Cepheids are good examples of cataclysmic variable stars.

Halo stars are all Population II objects.

The orbit of the Solar System around the Galaxy is similar to that of a planet, almost circular and in the galactic plane.

Stars within an emission nebula, such as M42 are considered Population I stars.

The globular stars clusters are the most obvious examples of Population II around us.

The bright blue stars of Orion's Belt are Population I, while our yellow Sun is population II.

Around us in the galactic plane, we find stars of a variety of ages and compositions.

The two stellar populations are extremes, but, in fact, stars with intermediate properties are common.

The thickness of the Galaxy near the Sun is about 1000 light years.

The orbits of Population II stars and globular clusters are much like comets, rising high above the galactic plane with eccentric orbits.

Planets are expected to be found orbiting most Population II stasr.

It would be very unlikely to find a massive young star out in the halo.

The rotation curve for our Galaxy shows stars beyond the Sun moving slower than expected.

The stars of the halo are all old, and those of the disk are all new.

Like our solar system, the whole Milky Way is about five billion years old.

The spiral arms are sites of continuous new star formation, accounting for their blue color and pink emission nebulae.

The density wave theory attempts to explain why the spiral arm structure persists over a long time.

Most of the dark matter in the Galaxy lies in the disk and galactic center.

The majority of the mass of the Milky Way lies farther out than the Sun's orbit.

Dark matter has not been observed at any electromagnetic wavelength.

Most of the mass of our galaxy lies between Earth and the Galactic center.

Between us and the Galactic Center lie about 100 billion solar masses.

The core of the Milky Way, Sagittarius A, is a strong radio source in the sky.

Our surveys of the Galactic Center are better done in infrared than visible light.

The Sgr A* black hole may contain three million solar masses.

In structure, our Milky Way is most similar to A. the Large Magellanic Cloud B.an upscale version of a globular cluster C. M31, the Andromeda Galaxy D. the Orion nebula E. none of these

All RR Lyrae stars have about the same A. period of six days B. distance of 32 light years C. galactic location and speed D. luminosity of about 100 Suns E. locations in the centers of globular star clusters

The first attempt to map the Galaxy via star counts was done by A. Galileo in 1612 B. William Herschel in the late eighteenth century C. Edward Barnard with long exposure photos in about 1900. D. Harlow Shapley with the RR Lyrae variables in 1920. E. Edwin Hubble with the New 100" Mt. Wilson telescope in the 1930s.

The RR Lyrae stars all have periods of A. less than a second B. several minutes C. several hours D. several days E. several weeks

Which of the following are most massive and luminous? A. brown dwarfs B. RR Lyrae variables C. white dwarfs D. T-Tauri variables E. Cepheid variables

A star in the instability strip of the H-R diagram would A. vary in both temperature and radius B. explode as a Type I supernova C. vary in temperature and brightness, but not in radius D. vary in brightness with an irregular pattern E. vary in temperature and radius, but not in brightness

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

Why was Herschel's strategy for mapping our Galaxy flawed? A. his infrared telescopes couldn't penetrate the dust clouds B. he used globular clusters, lying above the dust in the disc C. he relied on visual wavelengths, which are obscured by dust D. he used radio telescopes that didn't give enough resolution E. he assumed Earth was at the extreme edge of the Galaxy

Which of these variable stars would be classified as a RR Lyrae? A. a K giant with a period of 14 days B. an F giant with a period of 14 hours C. an M giant with a period of 140 days D. a B supergiant with a period of 0.14 days E. a pulsar with a period of 0.14 seconds

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 E. an M supergiant with a period of 140 days

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 E. infrared observations of the heat from its accretion disk around the black hole

Which is the correct description of the Sun's location within the Milky Way? A. at the outer edge of the galactic bulge but in the plane of the disc B. in the disc but at its outer edge C. as Herschel found, very close to the Galactic center D. above the disc an about one-third of the galactic radius from the center E. in the disc and about one-half a galactic radius from the center

The period-luminosity relation is critical in finding distances with A. RR Lyrae stars B. trigonometric parallaxes C. spectroscopic parallaxes D. Cepheid variables E. pulsars

What is one of the differences between Cepheids and RR Lyrae variables? A. Cepheids are giants, but RR Lyrae stars are still on the main sequence B. all Cepheids have the same brightness, but RR Lyrae stars vary greatly in luminosity C. the period-luminosity relation holds only for RR Lyrae stars D. the pulsations of RR Lyrae stars are much less regular than those of Cepheids E. the RR Lyrae stars have much shorter periods than Cepheids

Harlow Shapley found the Milky Way was A. centered on the Earth B. much smaller than previously thought C. rapidly expanding D. much larger than previously thought E. uniformly spherical in shape

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 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 statement about Population II is false? A. they are made of almost nothing but hydrogen and helium B. their orbits around the Galaxy resemble those of comets C. they formed first as the Galaxy formed D. at almost five billion years old, our Sun must belong to this older Population E. the globular clusters are their most obvious groupings

The orbits of Population II stars have been compared to A. planets around the Sun B. satellites around planets C. comets around the Sun D. binary stars E. the accretion disc around a black hole

Galactic disks appear blue because A. they contain no G, K, or M dwarfs B. they contain only blue reflection nebulae C. dust obscures the longer, red wavelengths D. O and B blue giants are much brighter than G, K, or M dwarfs E. dark matter gravitationally shifts all wavelengths toward the blue

From the Sun, the distance to the Galactic Center is about A. 8,000 light years B. 8 kpc C. 100,000 light years D. 225 million light years E. 100 billion parsecs

The Galactic Year is the time for our solar system to orbit the Galaxy; it is about A. 15 million years B. 225 million years C. 4.5 billion years D. 9.6 billion years E. 13.5 billion years

What is true about the stellar populations in the Galaxy? A. only old stars are found in the halo B. the main star forming regions are outside the Galactic plane C. the bluest stars are in the halo D. red stars are only found in the bulge E. most open clusters are in the halo

Detailed measurements of the disk and central bulge region of our Galaxy suggest our Milky Way is a A. normal spiral galaxy B. barred spiral galaxy C. very flat elliptical galaxy D. very dusty irregular galaxy E. quasar

Which of these objects have not been found in the Galactic Halo? A. RR Lyrae variables B. Cepheid variables C. emission nebulae D. Population II stars E. globular clusters

Between us and the Galactic Center, the Milky Way has a mass of A. several hundred thousand Suns B. one to two million Suns C. 250 million Suns D. 100 billion Suns E. over a trillion Suns

The tidal streams mapped in the Halo are similar to ______ in our solar system. A. the asteroid belt between Mars and Jupiter B. meteor swarms in old comet orbits C. the rings around the jovians D. the moons orbiting planets E. the solar wind

In our location in the Milky Way, the galactic disk is only about _____ light years thick. A. 10 B. 100 C. 1,000 D. 10,000 E. 100,000

Which of these is not typical of the Galaxy's spiral arms? A. hot, young blue Population I stars B. emission nebulae like M42 C. O and B stars D. open clusters E. Population II giants like orange Arcturus

In the formation of our Galaxy, the _____ formed first. A. galactic disk B. galactic center C. globular clusters D. planetary nebulae E. spiral arms

Which sequence of formation is most likely to be correct, oldest to youngest? A. halo, spiral arms, globular clusters B. globular clusters, open clusters, OB associations C. planetary nebulae, Population I stars, Population II stars D. Population I stars, Population II stars, Population III stars E. emission nebulae, planetary nebulae, dark nebulae

The visible color of the Galactic Bulge is A. blue from the OB associations B. yellow from the old Population II stars C. red from the emission nebulae D. black from the dust clouds E. brown from the dwarfs in the dark matter

Most of the new star formation in the Galaxy is found in the A. halo B. spiral arms C. bulge D. galactic center E. globular clusters

What use are 21 cm radio waves to galactic astronomers? A. they cut through the dusty cocoons to let us watch star birth B. we can reflect them off the core of the Galaxy C. their Doppler shifts let us map the motions and locations of gas in the spiral arms D. they bounce off stars like our sun to let us precisely measure their distances E. they pick up the cool, dark matter much better than can optical telescopes

Density waves may explain A. the lack of blue stars in the halo B. the random orbits of halo stars C. the density of red stars in the bulge D. the spiral arm structure of the Galaxy E. the large number of open clusters in the halo

What two observations allow us to calculate mass of the portion of the Galaxy within the Sun's orbit? A. the Sun's mass and velocity in orbit of the Galactic Center B. the Sun's age and period of the Galactic Year C. the sun's orbital velocity and its distance from the Galactic Center D. the Sun's mass and its age E. the Sun's composition and luminosity

The dark halo is now believed to extend at least A. 8 kpc B. 15,000 light years C. 15 kpc D. 100,000 light years E. 50 kpc

What observations suggest the mass of the Galaxy goes much farther out than its visible disc? A. 21 cm maps of the spiral arms B. the rotation curve of the outermost portions of the disc C. the orbits of the open clusters in the disc D. infrared observations of distant brown dwarfs E. x-ray images of other galaxies' discs from Chandra

Most of the mass of our Galaxy lies A. between Earth and the Galactic center B. in the bright spiral arms C. outside the luminous part of the Milky Way Galaxy D. at the galactic center E. within the bulge

Which method relies on the mass of a dark object revealing its presence? A. asteroidal occulations B. ring occulations C. stellar eclipses D. temporary brightening of a distant star by a gravity lens E. pulsars slowing down irregularly

Most of the mass of the MIlky Way seems to exist in the form of A. Population I stars in the disk Population II stars in the Halo C. hydrogen gas in the disk and spiral arms D. dark matter out in the Halo E. the black hole in the Galactic center

At the center of our Galaxy lies A. an intensely bright visible superstar B. a black hole of millions of solar masses C. a huge emission nebula D. the largest of all globular clusters E. a quasar

The radio source ______ is located in a place consistent with the center of our Galaxy. A. Cygnus X-1 B. 3C 273 C. 47 Tucanae D. M8, the Lagoon Nebula E. Sgr A*

The nearest comparable galaxy to our own lies in the constellation of _______.

The center of the Milky Way lies in the direction of the constellation ______.

All globular cluster stars belong to Population _____.

Based on his star counts, Herschel placed the Sun in the _____ of our Galaxy.

Herschel's map of the Galaxy was too small because _____ blocked much of the starlight.

To determine the distance to a Cepheid, we must measure its ______ of pulsation.

Edwin Hubble first found the distance to M21 in Andromeda with its _____ variable stars in its spiral arms.

Both RR Lyrae and Cepheid variables are giants that _____ in size over time.

Optically mapping the Milky Way is made very difficult because of ______ in the disk.

Star _____ have been vital in understanding stellar evolution, finding distances, and mapping the structure of our Galaxy.

Variable stars are ones whose _____ changes over time.

It was _____ in the Galactic disk that threw Herschel's model of the size and structure of the Galaxy off badly.

This diagram shows the period-luminosity relationship. A Cepheid variable with a period of 5 days will have a luminosity of _____ solar luminosities.

The _____ variables in the closer globular clusters were used by Harlow Shapley to find their distances.

The presence of _____ planets orbiting it shows us the Sun belongs to Population I.

If our Sun belonged to Population II, it is unlikely that _____ planets could orbit it.

William Herschel's attempt to map our Galaxy was based on _____ in different directions in space.

Harvard woman astronomer ______ discovered the period-luminosity relation.

Open clusters are found in the _____ of our Milky Way Galaxy.

Our solar system lies in the galaxy's ______, about 30,000 light years from the Galactic Center.

Almost all the stars we see around us with the naked eye are relatively _____ in age.

Virtually the entire disk of the Galaxy has been mapped using the _____ wavelength.

The three main components of the Milky Way galaxy are:

The spiral arms are made of bright stars belonging to Population ___.

Harlow Shapley found the visible disk of the Galaxy is about _____ kpc across.

With respect to heavy elements, the stars of the Halo are _____ in metals.

The spherical distribution of the globular clusters in the Halo reminds us of the similar distribution of cometary nuclei in the _____ cloud.

The distribution of stars in the Galactic Bulge reminds us of the distribution of objects in the solar system's _____ Belt beyond Neptune.

The age of the whole Galaxy has been found from studies of its oldest stars in the ____ clusters that orbit in the Halo.

The Galactic Disk has been flattened by the _____ of the Galaxy.

The distribution of Population II stars and globular clusters shows the Galaxy was more _____ in shape when it formed than it is now.

According to the ages of the globular clusters, our Galaxy is about _____ times as old as the solar system.

The _____ is the spherical outer portion of the Galaxy, including the orbits of the globular clusters and most dark matter.

It is the distribution of _____ atoms in the spiral arms that is measured with 21 cm radio maps.

Most of the hot, young blue stars lie in the _____ of our Galaxy.

According to its rotation curve, the majority of our Galaxy's mass is ______.

To the outer edge of the Galaxy, the rotation curve finds objects moving _____ than Kepler's Laws would lead us to expect.

We can estimate the mass of the Galaxy from observations of its _____ curve.

Counting only the material between us and the galactic Center, we measure a mass of _____ billion Suns.

Most of the mass of the Galaxy lies in the _____.

The bending of distant starlight by a closer object, resulting in a temporary brightening of the star, is called _____.

The strange object ____ is believed to be the black hole in the center of our Galaxy.

Sagittarius A* was first noted due to its strong ____ emissions.

What are the three main parts of our Galaxy?