Question 1

Which of the following describes the shape of dust particles,based on polarization of light?

Accepted Answer

A)  diamonds 
B)  cubes 
C)  spheres 
D)  disks 
E)  rodlike 
A)  diamonds 
B)  cubes 
C)  spheres 
D)  disks 
E)  rodlike

Question 2

What effect do even thin clouds of dust have on light passing through them?

Accepted Answer

A)  The light that passes through them is blue shifted due to the cloud's approach. 
B)  It dims and reddens the light of all more distant stars. 
C)  Even a little can completely block all light, such as the Horsehead Nebula. 
D)  Its motion causes the light of stars beyond to twinkle. 
E)  Its motion causes all light to be redshifted as it passes through these clouds. 
A)  The light that passes through them is blue shifted due to the cloud's approach. 
B)  It dims and reddens the light of all more distant stars. 
C)  Even a little can completely block all light, such as the Horsehead Nebula. 
D)  Its motion causes the light of stars beyond to twinkle. 
E)  Its motion causes all light to be redshifted as it passes through these clouds.

Question 3

Hydrogen is the major gas in the interstellar medium.

Accepted Answer

A) True 
 B)False

Question 4

An emission nebula appears primarily ________ in color,due to ionized hydrogen.

Accepted Answer

The answer of An emission nebula appears primarily ________ in...

Question 5

Explain why interstellar molecules are best observed at radio wavelengths.

Accepted Answer

Interstellar molecules are best observed

Question 6

The overall dimming of starlight passing through dust clouds is called ________.

Accepted Answer

The answer of The overall dimming of starlight passing through...

Question 7

Unlike the ultraviolet photons originally emitted by the embedded stars of an emission nebula,the photons emitted by the recombination of electrons with atoms:

Accepted Answer

A)  do not escape the nebula. 
B)  escape the nebula. 
C)  are re-absorbed by neutral hydrogen atoms. 
D)  bounce around inside the nebula. 
E)  are scattered by the dust particles. 
A)  do not escape the nebula. 
B)  escape the nebula. 
C)  are re-absorbed by neutral hydrogen atoms. 
D)  bounce around inside the nebula. 
E)  are scattered by the dust particles.

Question 8

The relative density of dust to gas is least in which place?

Accepted Answer

A)  the interstellar medium 
B)  dark nebulae 
C)  the atmosphere of Earth 
D)  molecular clouds 
E)  reflection nebulae 
A)  the interstellar medium 
B)  dark nebulae 
C)  the atmosphere of Earth 
D)  molecular clouds 
E)  reflection nebulae

Question 9

Contrast observations of ionized and neutral hydrogen in space.

Accepted Answer

Emission nebula glow bright red from the

Question 10

Dust particles and magnetic fields in the interstellar medium are revealed by ________ of light.

Accepted Answer

The answer of Dust particles and magnetic fields in the...

Question 11

Emission nebula take up about how much of the Milky Way galaxy?

Accepted Answer

A)  1% 
B)  5% 
C)  10% 
D)  99% 
E)  100% 
A)  1% 
B)  5% 
C)  10% 
D)  99% 
E)  100%

Question 12

Emission nebula appear red because they are associated with cool red giant stars.

Accepted Answer

A) True 
 B)False

Question 13

The 21 cm line of hydrogen is strongly absorbed by interstellar dust.

Accepted Answer

A) True 
 B)False

Question 14

The form of electromagnetic radiation most effectively blocked by a dark nebulae is ________.

Accepted Answer

The answer of The form of electromagnetic radiation most effectively...

Question 15

Dark dust clouds radiate mainly in the radio portion of the electromagnetic spectrum.

Accepted Answer

A) True 
 B)False

Question 16

Neutral hydrogen is most obvious in the electromagnetic spectrum:

Accepted Answer

A)  in yellow light of the Sun's continuum. 
B)  at 656.3 nm, hydrogen alpha red. 
C)  at 21 cm in the radio region. 
D)  at 121.3 nm, the Lyman alpha ultraviolet line. 
E)  Neutral hydrogen has yet to be detected in space. 
A)  in yellow light of the Sun's continuum. 
B)  at 656.3 nm, hydrogen alpha red. 
C)  at 21 cm in the radio region. 
D)  at 121.3 nm, the Lyman alpha ultraviolet line. 
E)  Neutral hydrogen has yet to be detected in space.

Question 17

What information does 21 cm radiation provide about the gas clouds?

Accepted Answer

A)  their motion 
B)  their distribution 
C)  their density 
D)  their temperature 
E)  all of these 
A)  their motion 
B)  their distribution 
C)  their density 
D)  their temperature 
E)  all of these

Question 18

How is 21 cm radiation produced?

Accepted Answer

When the electron orbiting the

Question 19

Complex molecules in space are found:

Accepted Answer

A)  in the photospheres of red giant stars. 
B)  inside dense dust clouds. 
C)  in the coronas of stars like our Sun. 
D)  scattered evenly throughout interstellar space. 
E)  surrounding the more energetic young stars. 
A)  in the photospheres of red giant stars. 
B)  inside dense dust clouds. 
C)  in the coronas of stars like our Sun. 
D)  scattered evenly throughout interstellar space. 
E)  surrounding the more energetic young stars.

Question 20

A cold region of dust which scatters the light of nearby stars produces a nebula which appears ________ in color,such as the one encompassing the Pleiades cluster.

Accepted Answer

The answer of A cold region of dust which scatters...

Exam 18: The Interstellar Medium: Gas and Dust among the Stars

Which of the following describes the shape of dust particles,based on polarization of light?

What effect do even thin clouds of dust have on light passing through them?

Hydrogen is the major gas in the interstellar medium.

An emission nebula appears primarily ________ in color,due to ionized hydrogen.

Explain why interstellar molecules are best observed at radio wavelengths.

The overall dimming of starlight passing through dust clouds is called ________.

Unlike the ultraviolet photons originally emitted by the embedded stars of an emission nebula,the photons emitted by the recombination of electrons with atoms:

The relative density of dust to gas is least in which place?

Contrast observations of ionized and neutral hydrogen in space.

Dust particles and magnetic fields in the interstellar medium are revealed by ________ of light.

Emission nebula take up about how much of the Milky Way galaxy?

Emission nebula appear red because they are associated with cool red giant stars.

The 21 cm line of hydrogen is strongly absorbed by interstellar dust.

The form of electromagnetic radiation most effectively blocked by a dark nebulae is ________.

Dark dust clouds radiate mainly in the radio portion of the electromagnetic spectrum.

Neutral hydrogen is most obvious in the electromagnetic spectrum:

What information does 21 cm radiation provide about the gas clouds?

How is 21 cm radiation produced?

Complex molecules in space are found:

A cold region of dust which scatters the light of nearby stars produces a nebula which appears ________ in color,such as the one encompassing the Pleiades cluster.

Charting the Heavens: The Foundations of Astronomy

The Copernican Revolution: The Birth of Modern Science

Radiation: Information from the Cosmos

Spectroscopy: The Inner Workings of Atoms

Telescopes: The Tools of Astronomy

The Solar System: Comparative Planetology and Formation Models

Earth: Our Home in Space

The Moon and Mercury: Scorched and Battered Worlds

Venus: Earth's Sister Planet

Mars: A Near Miss for Life?

Jupiter: Giant of the Solar System

Saturn: Spectacular Rings and Mysterious Moons

Uranus and Neptune: The Outer Worlds of the Solar System

Solar System Debris: Keys to Our Origin

Exoplanets: Planetary Systems Beyond Our Own

The Sun: Our Parent Star

The Stars: Giants,Dwarfs,and the Main Sequence

Star Formation: A Traumatic Birth

Stellar Evolution: The Life and Death of a Star

Stellar Explosions: Novae,Supernovae,and the Formation of the Elements

Neutron Stars and Black Holes: Strange States of Matter

The Milky Way Galaxy: A Spiral in Space

Galaxies: Building Blocks of the Universe

Galaxies and Dark Matter: The Large-Scale Structure of the Cosmos

Cosmology: The Big Bang and the Fate of the Universe

The Early Universe: Toward the Beginning of Time

Life in the Universe: Are We Alone?

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