Question 1

A neutral hydrogen atom consists of a proton and an electron. The energy of the atom is

Accepted Answer

A)  the same regardless of the relative spin orientations of the two particles. 
B)  highest when the proton spin and the electron spin are perpendicular to each other. 
C)  highest when the proton spin and the electron spin directions are parallel. 
D)  highest when the proton spin and the electron spin directions are antiparallel. 
A)  the same regardless of the relative spin orientations of the two particles. 
B)  highest when the proton spin and the electron spin are perpendicular to each other. 
C)  highest when the proton spin and the electron spin directions are parallel. 
D)  highest when the proton spin and the electron spin directions are antiparallel.

Question 2

Which type of radiation has been MOST effective in evaluating the spiral arm structure of the Milky Way Galaxy?

Accepted Answer

A)  21-cm radio emission from electron spin-flip transitions in cool hydrogen gas 
B)  Lyman-$\alpha$ultraviolet emission from hot hydrogen gas 
C)  synchrotron radiation from electrons spiraling in magnetic fields in the spiral arms 
D)  neutrinos from exploding stars in the spiral arms, since they can easily penetrate dust and gas 
A)  21-cm radio emission from electron spin-flip transitions in cool hydrogen gas 
B)  Lyman-$\alpha$ultraviolet emission from hot hydrogen gas 
C)  synchrotron radiation from electrons spiraling in magnetic fields in the spiral arms 
D)  neutrinos from exploding stars in the spiral arms, since they can easily penetrate dust and gas

Question 3

The Milky Way Galaxy appears to have a spiral structure with

Accepted Answer

A)  four separate major arms. 
B)  a dozen loosely wound arms. 
C)  one "arm" wound around the nucleus 4 times. 
D)  two major arms wound twice around the nucleus. 
A)  four separate major arms. 
B)  a dozen loosely wound arms. 
C)  one "arm" wound around the nucleus 4 times. 
D)  two major arms wound twice around the nucleus.

Question 4

The event that settled the Shapley-Curtis debate about "spiral nebulae" was

Accepted Answer

A)  Edwin Hubble measuring the distance to the Andromeda Galaxy. 
B)  Arno Penzias and Robert Wilson detecting the cosmic microwave background radiation. 
C)  Albert Einstein showing that gravity can bend the path of light. 
D)  Edwin Hubble showing that the universe was expanding. 
A)  Edwin Hubble measuring the distance to the Andromeda Galaxy. 
B)  Arno Penzias and Robert Wilson detecting the cosmic microwave background radiation. 
C)  Albert Einstein showing that gravity can bend the path of light. 
D)  Edwin Hubble showing that the universe was expanding.

Question 5

The Milky Way Galaxy

Accepted Answer

A)  is one of many billions of galaxies in the universe. 
B)  is unique in the universe in showing definite spiral structure. 
C)  contains the whole universe; everything observable is within its volume. 
D)  is one of only a few spiral galaxies; most other galaxies in the universe are amorphous collections of stars shaped like ellipsoids. 
A)  is one of many billions of galaxies in the universe. 
B)  is unique in the universe in showing definite spiral structure. 
C)  contains the whole universe; everything observable is within its volume. 
D)  is one of only a few spiral galaxies; most other galaxies in the universe are amorphous collections of stars shaped like ellipsoids.

Question 6

Which concept concerning the diffuse objects observed by Herschel was proposed by Kant in the 1700s and further expounded by the Earl of Rosse based on observations made in 1845 with his world-class telescope in Ireland?

Accepted Answer

A)  Many of the diffuse objects in Earth's sky are moving rapidly away from the Milky Way Galaxy. 
B)  Many of the nebulae in the sky are separate entities beyond the Milky Way Galaxy. 
C)  The diffuse objects observed by Herschel and known as planetary nebulae were in fact planets orbiting other stars in the Milky Way Galaxy. 
D)  All the diffuse nebulae seen in the sky are gas clouds in the Milky Way Galaxy. 
A)  Many of the diffuse objects in Earth's sky are moving rapidly away from the Milky Way Galaxy. 
B)  Many of the nebulae in the sky are separate entities beyond the Milky Way Galaxy. 
C)  The diffuse objects observed by Herschel and known as planetary nebulae were in fact planets orbiting other stars in the Milky Way Galaxy. 
D)  All the diffuse nebulae seen in the sky are gas clouds in the Milky Way Galaxy.

Question 7

How is cool, neutral hydrogen gas, H I, detected in the spiral arms of galaxies?

Accepted Answer

A)  by the absorption of infrared radiation from extragalactic sources 
B)  by its Balmer line emissions 
C)  by its 21-cm line radio emissions 
D)  by its ultraviolet Lyman-$\alpha$ hydrogen line emissions 
A)  by the absorption of infrared radiation from extragalactic sources 
B)  by its Balmer line emissions 
C)  by its 21-cm line radio emissions 
D)  by its ultraviolet Lyman-$\alpha$ hydrogen line emissions

Question 8

Harlow Shapley first located the center of the Milky Way Galaxy in 1917 by

Accepted Answer

A)  measuring the positions of supernova explosions throughout the Galaxy. 
B)  observing the distribution of globular clusters in the galactic halo. 
C)  measuring redshifts of stars in the galactic plane and disk. 
D)  observing the distribution of hydrogen gas, measured by 21-cm radio emission. 
A)  measuring the positions of supernova explosions throughout the Galaxy. 
B)  observing the distribution of globular clusters in the galactic halo. 
C)  measuring redshifts of stars in the galactic plane and disk. 
D)  observing the distribution of hydrogen gas, measured by 21-cm radio emission.

Question 9

What is a "hypervelocity" star?

Accepted Answer

A)  It is one of the stars in rapid orbital motion close to the supermassive black hole in the galactic center. 
B)  A star moving faster than the escape speed from the galaxy. 
C)  This is the name given to a few stars that have been detected moving around the galactic center in the opposite direction from the general galactic rotation. Although their speeds are not unusual, their speeds relative to normal stars are very large. 
D)  These are stars that move around the galactic center in the middle of the galactic plane, but travel much faster than neighboring stars-seemingly in defiance of Kepler's third law. 
A)  It is one of the stars in rapid orbital motion close to the supermassive black hole in the galactic center. 
B)  A star moving faster than the escape speed from the galaxy. 
C)  This is the name given to a few stars that have been detected moving around the galactic center in the opposite direction from the general galactic rotation. Although their speeds are not unusual, their speeds relative to normal stars are very large. 
D)  These are stars that move around the galactic center in the middle of the galactic plane, but travel much faster than neighboring stars-seemingly in defiance of Kepler's third law.

Question 10

Which parameter is plotted as a function of distance from the galactic center in a rotation curve of a galaxy?

Accepted Answer

A)  mass of matter inside the distance from the galactic center 
B)  thickness of the galactic disk 
C)  mass of cool hydrogen gas 
D)  speed of stars orbiting the galactic center 
A)  mass of matter inside the distance from the galactic center 
B)  thickness of the galactic disk 
C)  mass of cool hydrogen gas 
D)  speed of stars orbiting the galactic center

Question 11

In the Milky Way Galaxy, young stars are found

Accepted Answer

A)  everywhere. 
B)  only at the galactic center. 
C)  in the disk and spiral arms. 
D)  in the globular clusters in the galactic halo. 
A)  everywhere. 
B)  only at the galactic center. 
C)  in the disk and spiral arms. 
D)  in the globular clusters in the galactic halo.

Question 12

Who was the first person to observe the spiral structure of distant galaxies with a telescope?

Accepted Answer

A)  Sir Isaac Newton 
B)  Sir William Herschel 
C)  William Parsons, Earl of Rosse 
D)  Galileo Galilei 
A)  Sir Isaac Newton 
B)  Sir William Herschel 
C)  William Parsons, Earl of Rosse 
D)  Galileo Galilei

Question 13

The Sun's position in the Milky Way Galaxy is

Accepted Answer

A)  unknown because Earth's view is too severely restricted by interstellar dust. 
B)  in the disk of the Galaxy. 
C)  in the Galaxy's central bulge. 
D)  in the spherical halo, somewhat above and outside the spiral arms. 
A)  unknown because Earth's view is too severely restricted by interstellar dust. 
B)  in the disk of the Galaxy. 
C)  in the Galaxy's central bulge. 
D)  in the spherical halo, somewhat above and outside the spiral arms.

Question 14

The supermassive black hole at the center of the Galaxy has a diameter of approximately 8 *10-7 pc and is approximately 8000 pc away from Earth. What is the angular size of the black hole?

Accepted Answer

A)  about 2 * 105 arcseconds 
B)  about 0.2 arcseconds 
C)  about 1.25 * 10-4 arcseconds 
D)  about 2 * 10-5 arcseconds 
A)  about 2 * 105 arcseconds 
B)  about 0.2 arcseconds 
C)  about 1.25 * 10-4 arcseconds 
D)  about 2 * 10-5 arcseconds

Question 15

What is the evidence that indicates to astronomers that a supermassive black hole exists at the center of the Milky Way Galaxy?

Accepted Answer

A)  A Doppler shift of light from stars in the near neighborhood of the galactic center indicates that the stars are falling inward at very high speeds. 
B)  The Sun's motion in space shows that, if Kepler's law holds for its orbit around the galactic center, there must be a very massive object at the center of the Milky Way. 
C)  No electromagnetic radiation at all comes from the precise position of the galactic center, and it just looks like a dark void in space. 
D)  Measurement of gas clouds orbiting the galactic center at very high speeds indicates that they would rapidly move out of the Galaxy unless some very massive object was holding them in orbit. 
A)  A Doppler shift of light from stars in the near neighborhood of the galactic center indicates that the stars are falling inward at very high speeds. 
B)  The Sun's motion in space shows that, if Kepler's law holds for its orbit around the galactic center, there must be a very massive object at the center of the Milky Way. 
C)  No electromagnetic radiation at all comes from the precise position of the galactic center, and it just looks like a dark void in space. 
D)  Measurement of gas clouds orbiting the galactic center at very high speeds indicates that they would rapidly move out of the Galaxy unless some very massive object was holding them in orbit.

Question 16

Does the halo of the Milky Way Galaxy include other galaxies?

Accepted Answer

A)  No. It is not possible for one galaxy to orbit another galaxy. 
B)  No. The halo is limited to field stars and globular clusters. 
C)  Yes. The halo region includes the Andromeda Galaxy. 
D)  Yes. The halo region includes several small galaxies. 
A)  No. It is not possible for one galaxy to orbit another galaxy. 
B)  No. The halo is limited to field stars and globular clusters. 
C)  Yes. The halo region includes the Andromeda Galaxy. 
D)  Yes. The halo region includes several small galaxies.

Question 17

The dimensions of the disk of the Milky Way Galaxy are diameter _____, thickness _____.

Accepted Answer

A)  100,000 ly; 2000 ly 
B)  10,000 ly; 28,000 ly 
C)  2000 ly; 100,000 ly 
D)  28,000 ly; 2000 ly 
A)  100,000 ly; 2000 ly 
B)  10,000 ly; 28,000 ly 
C)  2000 ly; 100,000 ly 
D)  28,000 ly; 2000 ly

Question 18

Hubble carried out the determination of the distance to the Andromeda "nebula" (which finally resolved the Shapley-Curtis debate on the nature of "spiral nebulae") by observing

Accepted Answer

A)  pulsars. 
B)  Cepheid variable stars. 
C)  the Doppler shift of stars in the "nebula." 
D)  the main sequence of stars in the "nebula." 
A)  pulsars. 
B)  Cepheid variable stars. 
C)  the Doppler shift of stars in the "nebula." 
D)  the main sequence of stars in the "nebula."

Question 19

Distances to a nearby galaxy can be determined MOST accurately by

Accepted Answer

A)  measuring the periods of pulsating stars. 
B)  measuring the chemical compositions of the brightest stars. 
C)  measuring the shifts of spectral lines from the Milky Way Galaxy. 
D)  measuring the total amount of energy received from the Milky Way Galaxy. 
A)  measuring the periods of pulsating stars. 
B)  measuring the chemical compositions of the brightest stars. 
C)  measuring the shifts of spectral lines from the Milky Way Galaxy. 
D)  measuring the total amount of energy received from the Milky Way Galaxy.

Question 20

A rotation curve is a plot of the rotational velocity of a galaxy as a function of the distance away from the galactic center. Predictions for rotation curves for spiral galaxies suggest that the curve should decline beyond the galactic bulge. Actual measurements, however, show that the rotation curve is flat beyond the bulge. What does this deviation from prediction state about spiral galaxies, including the Milky Way?

Accepted Answer

A)  Spiral galaxies are not rotating as rapidly as previously believed. 
B)  The spiral arms move together as a rigid object. 
C)  There is a great deal of unseen mass surrounding the visible galaxy. 
D)  The centers of spiral galaxies contain supermassive black holes. 
A)  Spiral galaxies are not rotating as rapidly as previously believed. 
B)  The spiral arms move together as a rigid object. 
C)  There is a great deal of unseen mass surrounding the visible galaxy. 
D)  The centers of spiral galaxies contain supermassive black holes.

A neutral hydrogen atom consists of a proton and an electron. The energy of the atom is

Which type of radiation has been MOST effective in evaluating the spiral arm structure of the Milky Way Galaxy?

The Milky Way Galaxy appears to have a spiral structure with

The event that settled the Shapley-Curtis debate about "spiral nebulae" was

The Milky Way Galaxy

Which concept concerning the diffuse objects observed by Herschel was proposed by Kant in the 1700s and further expounded by the Earl of Rosse based on observations made in 1845 with his world-class telescope in Ireland?

How is cool, neutral hydrogen gas, H I, detected in the spiral arms of galaxies?

Harlow Shapley first located the center of the Milky Way Galaxy in 1917 by

What is a "hypervelocity" star?

Which parameter is plotted as a function of distance from the galactic center in a rotation curve of a galaxy?

In the Milky Way Galaxy, young stars are found

Who was the first person to observe the spiral structure of distant galaxies with a telescope?

The Sun's position in the Milky Way Galaxy is

The supermassive black hole at the center of the Galaxy has a diameter of approximately 8 *10^-7 pc and is approximately 8000 pc away from Earth. What is the angular size of the black hole?

What is the evidence that indicates to astronomers that a supermassive black hole exists at the center of the Milky Way Galaxy?

Does the halo of the Milky Way Galaxy include other galaxies?

The dimensions of the disk of the Milky Way Galaxy are diameter _, thickness _.

Hubble carried out the determination of the distance to the Andromeda "nebula" (which finally resolved the Shapley-Curtis debate on the nature of "spiral nebulae") by observing

Distances to a nearby galaxy can be determined MOST accurately by

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

A neutral hydrogen atom consists of a proton and an electron. The energy of the atom is

Which type of radiation has been MOST effective in evaluating the spiral arm structure of the Milky Way Galaxy?

The Milky Way Galaxy appears to have a spiral structure with

The event that settled the Shapley-Curtis debate about "spiral nebulae" was

The Milky Way Galaxy

Which concept concerning the diffuse objects observed by Herschel was proposed by Kant in the 1700s and further expounded by the Earl of Rosse based on observations made in 1845 with his world-class telescope in Ireland?

How is cool, neutral hydrogen gas, H I, detected in the spiral arms of galaxies?

Harlow Shapley first located the center of the Milky Way Galaxy in 1917 by

What is a "hypervelocity" star?

Which parameter is plotted as a function of distance from the galactic center in a rotation curve of a galaxy?

In the Milky Way Galaxy, young stars are found

Who was the first person to observe the spiral structure of distant galaxies with a telescope?

The Sun's position in the Milky Way Galaxy is

The supermassive black hole at the center of the Galaxy has a diameter of approximately 8 *10-7 pc and is approximately 8000 pc away from Earth. What is the angular size of the black hole?

What is the evidence that indicates to astronomers that a supermassive black hole exists at the center of the Milky Way Galaxy?

Does the halo of the Milky Way Galaxy include other galaxies?

The dimensions of the disk of the Milky Way Galaxy are diameter _____, thickness _____.

Hubble carried out the determination of the distance to the Andromeda "nebula" (which finally resolved the Shapley-Curtis debate on the nature of "spiral nebulae") by observing

Distances to a nearby galaxy can be determined MOST accurately by

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

The supermassive black hole at the center of the Galaxy has a diameter of approximately 8 *10^-7 pc and is approximately 8000 pc away from Earth. What is the angular size of the black hole?

The dimensions of the disk of the Milky Way Galaxy are diameter _, thickness _.