Question 1

What fraction of the mass of the Milky Way Galaxy is in a form that astronomers have been able to see?

Accepted Answer

A)  about 50% 
B)  100%-whoever heard of matter that can't be seen? 
C)  about 10% 
D)  about 90% 
A)  about 50% 
B)  100%-whoever heard of matter that can't be seen? 
C)  about 10% 
D)  about 90%

Question 2

A Cepheid variable star with a pulsation period of a few days is seen in the spiral arm of a galaxy. Its apparent brightness is measured as 104 times fainter than an equivalent star 1000 ly away from the Sun in the Milky Way Galaxy. Assuming no light absorption between galaxies, how far away is the more distant Cepheid?

Accepted Answer

A)  107 ly (104 times farther away) 
B)  10,000 ly (10 times farther away) 
C)  10 ly (100 times closer) 
D)  100,000 ly (100 times farther away) 
A)  107 ly (104 times farther away) 
B)  10,000 ly (10 times farther away) 
C)  10 ly (100 times closer) 
D)  100,000 ly (100 times farther away)

Question 3

What is microlensing?

Accepted Answer

A)  beaming of radiation by accretion disks 
B)  use of small telescopes to enhance contrast by eliminating scattered light 
C)  focusing of starlight by the gravitational fields of "small" objects like planets or brown dwarfs 
D)  focusing of starlight by planetary atmospheres 
A)  beaming of radiation by accretion disks 
B)  use of small telescopes to enhance contrast by eliminating scattered light 
C)  focusing of starlight by the gravitational fields of "small" objects like planets or brown dwarfs 
D)  focusing of starlight by planetary atmospheres

Question 4

The factor that misled Herschel into concluding that the stars of the Milky Way were distributed with the Sun at the center of the Milky Way Galaxy was

Accepted Answer

A)  hot hydrogen gas in the Galaxy, its emission hiding the more distant stars. 
B)  interstellar dust that obscured the more distant stars and thereby localized his observations. 
C)  gravitational bending of light by the mass of the Galaxy, distorting the relative positions of the stars. 
D)  that most of the "stars" he measured were in fact distant galaxies that are distributed uniformly around the Sun. 
A)  hot hydrogen gas in the Galaxy, its emission hiding the more distant stars. 
B)  interstellar dust that obscured the more distant stars and thereby localized his observations. 
C)  gravitational bending of light by the mass of the Galaxy, distorting the relative positions of the stars. 
D)  that most of the "stars" he measured were in fact distant galaxies that are distributed uniformly around the Sun.

Question 5

What fraction of the mass of the Milky Way Galaxy appears to be in the form of "dark matter," which astronomers cannot see but can detect through its gravitational influence?

Accepted Answer

A)  about 50% 
B)  about 10% 
C)  0%-whoever heard of matter that can't be seen? 
D)  about 90% 
A)  about 50% 
B)  about 10% 
C)  0%-whoever heard of matter that can't be seen? 
D)  about 90%

Question 6

Approximately how far is the Sun from the center of the Milky Way Galaxy?

Accepted Answer

A)  2 kpc 
B)  8 kpc 
C)  49 kpc 
D)  160 kpc 
A)  2 kpc 
B)  8 kpc 
C)  49 kpc 
D)  160 kpc

Question 7

The speed of the Sun in its orbit around the Milky Way Galaxy is deduced by reference to and observations of

Accepted Answer

A)  the orbital motions of stars near the Sun. 
B)  globular clusters. 
C)  Cepheid variables, which provide a distance standard. 
D)  the galactic center, about which the Sun is orbiting. 
A)  the orbital motions of stars near the Sun. 
B)  globular clusters. 
C)  Cepheid variables, which provide a distance standard. 
D)  the galactic center, about which the Sun is orbiting.

Question 8

The halo of the Milky Way Galaxy consists of a number of objects that orbit the galactic center and periodically pass through the galactic plane. Which of these objects are NOT among the galactic halo objects?

Accepted Answer

A)  supermassive black holes 
B)  galaxies 
C)  globular clusters 
D)  field stars 
A)  supermassive black holes 
B)  galaxies 
C)  globular clusters 
D)  field stars

Question 9

The one component of the material of the Milky Way Galaxy that prevents astronomers from seeing and photographing the galactic center at optical wavelengths is

Accepted Answer

A)  very cold hydrogen gas. 
B)  interstellar dust. 
C)  the glare of light from nearby stars. 
D)  hot hydrogen gas. 
A)  very cold hydrogen gas. 
B)  interstellar dust. 
C)  the glare of light from nearby stars. 
D)  hot hydrogen gas.

Question 10

The time for the Sun to orbit the galactic center once in its motion in the Milky Way is

Accepted Answer

A)  28,000 years. 
B)  230 million years. 
C)  about 500,000 years. 
D)  2.3 million years. 
A)  28,000 years. 
B)  230 million years. 
C)  about 500,000 years. 
D)  2.3 million years.

Question 11

Astronomers have observed the central region of the Milky Way Galaxy in a number of wavelength ranges. With which one of the ranges is it MOST difficult to obtain information?

Accepted Answer

A)  infrared 
B)  radio 
C)  visible 
D)  gamma ray 
A)  infrared 
B)  radio 
C)  visible 
D)  gamma ray

Question 12

The stars in the Milky Way Galaxy

Accepted Answer

A)  obey Hubble's law of recession. 
B)  are all receding from the galactic center. 
C)  move generally around the galactic center. 
D)  number between 8 and 10 million. 
A)  obey Hubble's law of recession. 
B)  are all receding from the galactic center. 
C)  move generally around the galactic center. 
D)  number between 8 and 10 million.

Question 13

What is microlensing?

Accepted Answer

A)  minute shift in the apparent position of a star as a massive object passes in front of it 
B)  temporary brightening of a star as a massive object passes in front of it 
C)  temporary disappearance of a star as a massive object passes in front of it 
D)  gradual reduction in brightness of a star as a massive object passes in front of it 
A)  minute shift in the apparent position of a star as a massive object passes in front of it 
B)  temporary brightening of a star as a massive object passes in front of it 
C)  temporary disappearance of a star as a massive object passes in front of it 
D)  gradual reduction in brightness of a star as a massive object passes in front of it

Question 14

Cepheid variable stars are useful to astronomers as indicators of

Accepted Answer

A)  stars with very high-speed motion. 
B)  white dwarf star behavior. 
C)  the existence of black holes. 
D)  distance, particularly to nearby galaxies. 
A)  stars with very high-speed motion. 
B)  white dwarf star behavior. 
C)  the existence of black holes. 
D)  distance, particularly to nearby galaxies.

Question 15

In the mid-nineteenth century, Lord Rosse built the world's largest telescope, the "Leviathan of Parsonstown." What major disadvantage did Rosse have in using his telescope at this time?

Accepted Answer

A)  The mirror, although large, was not made using modern techniques. It had so much distortion that deep sky objects like galaxies could not be seen clearly. 
B)  No catalogs of deep sky objects were available, so Rosse did not know where to locate anything of interest. 
C)  The telescope used an objective lens rather than a mirror and thus suffered from distortion due to sagging and chromatic aberration. 
D)  Photography was not available to record the images Rosse observed. 
A)  The mirror, although large, was not made using modern techniques. It had so much distortion that deep sky objects like galaxies could not be seen clearly. 
B)  No catalogs of deep sky objects were available, so Rosse did not know where to locate anything of interest. 
C)  The telescope used an objective lens rather than a mirror and thus suffered from distortion due to sagging and chromatic aberration. 
D)  Photography was not available to record the images Rosse observed.

Question 16

The MOST important reason globular clusters are useful for finding the speed of the Sun in its orbit around the Milky Way is that

Accepted Answer

A)  globular clusters are bright and easily seen at large distances. 
B)  globular clusters on average rotate at the same speed as the Sun around the center of the Galaxy. 
C)  globular clusters are distributed uniformly around the Galaxy. 
D)  the average velocity of all the globular clusters must be zero if the globular clusters are to maintain their orbits around the galactic center. 
A)  globular clusters are bright and easily seen at large distances. 
B)  globular clusters on average rotate at the same speed as the Sun around the center of the Galaxy. 
C)  globular clusters are distributed uniformly around the Galaxy. 
D)  the average velocity of all the globular clusters must be zero if the globular clusters are to maintain their orbits around the galactic center.

Question 17

The famous nineteenth-century observational astronomer Lord Rosse built the largest telescope of his time (and discovered the spiral nature of many so-called "nebulae") in which country?

Accepted Answer

A)  England 
B)  United States 
C)  Ireland 
D)  Germany 
A)  England 
B)  United States 
C)  Ireland 
D)  Germany

What fraction of the mass of the Milky Way Galaxy is in a form that astronomers have been able to see?

What is microlensing?

The factor that misled Herschel into concluding that the stars of the Milky Way were distributed with the Sun at the center of the Milky Way Galaxy was

What fraction of the mass of the Milky Way Galaxy appears to be in the form of "dark matter," which astronomers cannot see but can detect through its gravitational influence?

Approximately how far is the Sun from the center of the Milky Way Galaxy?

The speed of the Sun in its orbit around the Milky Way Galaxy is deduced by reference to and observations of

The halo of the Milky Way Galaxy consists of a number of objects that orbit the galactic center and periodically pass through the galactic plane. Which of these objects are NOT among the galactic halo objects?

The one component of the material of the Milky Way Galaxy that prevents astronomers from seeing and photographing the galactic center at optical wavelengths is

The time for the Sun to orbit the galactic center once in its motion in the Milky Way is

Astronomers have observed the central region of the Milky Way Galaxy in a number of wavelength ranges. With which one of the ranges is it MOST difficult to obtain information?

The stars in the Milky Way Galaxy

What is microlensing?

Cepheid variable stars are useful to astronomers as indicators of

In the mid-nineteenth century, Lord Rosse built the world's largest telescope, the "Leviathan of Parsonstown." What major disadvantage did Rosse have in using his telescope at this time?

The MOST important reason globular clusters are useful for finding the speed of the Sun in its orbit around the Milky Way is that

The famous nineteenth-century observational astronomer Lord Rosse built the largest telescope of his time (and discovered the spiral nature of many so-called "nebulae") in which country?

Discovering the Night Sky

Gravitation and the Motion of the Planets

Light and Telescopes

Atomic Physics and Spectra

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Lives of Stars From Birth Through Middle Age

The Death of Stars

Black Holes: Matters of Gravity

Galaxies

Quasars and Other Active Galaxies

Cosmology

Astrobiology

Filters

Exam 16: The Milky Way Galaxy

What fraction of the mass of the Milky Way Galaxy is in a form that astronomers have been able to see?

What is microlensing?

The factor that misled Herschel into concluding that the stars of the Milky Way were distributed with the Sun at the center of the Milky Way Galaxy was

What fraction of the mass of the Milky Way Galaxy appears to be in the form of "dark matter," which astronomers cannot see but can detect through its gravitational influence?

Approximately how far is the Sun from the center of the Milky Way Galaxy?

The speed of the Sun in its orbit around the Milky Way Galaxy is deduced by reference to and observations of

The halo of the Milky Way Galaxy consists of a number of objects that orbit the galactic center and periodically pass through the galactic plane. Which of these objects are NOT among the galactic halo objects?

The one component of the material of the Milky Way Galaxy that prevents astronomers from seeing and photographing the galactic center at optical wavelengths is

The time for the Sun to orbit the galactic center once in its motion in the Milky Way is

Astronomers have observed the central region of the Milky Way Galaxy in a number of wavelength ranges. With which one of the ranges is it MOST difficult to obtain information?

The stars in the Milky Way Galaxy

What is microlensing?

Cepheid variable stars are useful to astronomers as indicators of

In the mid-nineteenth century, Lord Rosse built the world's largest telescope, the "Leviathan of Parsonstown." What major disadvantage did Rosse have in using his telescope at this time?

The MOST important reason globular clusters are useful for finding the speed of the Sun in its orbit around the Milky Way is that

The famous nineteenth-century observational astronomer Lord Rosse built the largest telescope of his time (and discovered the spiral nature of many so-called "nebulae") in which country?

Discovering the Night Sky

Gravitation and the Motion of the Planets

Light and Telescopes

Atomic Physics and Spectra

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Lives of Stars From Birth Through Middle Age

The Death of Stars

Black Holes: Matters of Gravity

Galaxies

Quasars and Other Active Galaxies

Cosmology

Astrobiology

Filters