Question 1

The density of interstellar dust is very low, yet it still blocks starlight because

Accepted Answer

A)  it is so cold it absorbs higher energy photons. 
B)  the dust particles are irregular in shape. 
C)  there is 100 times more opaque gas than dust present in the interstellar medium. 
D)  ice particles reflect all light back toward their stars, not toward us. 
E)  the dust particles are about the same size as the light waves they absorb. 
A)  it is so cold it absorbs higher energy photons. 
B)  the dust particles are irregular in shape. 
C)  there is 100 times more opaque gas than dust present in the interstellar medium. 
D)  ice particles reflect all light back toward their stars, not toward us. 
E)  the dust particles are about the same size as the light waves they absorb.

Question 2

Name two telescopes that in recent years have improved our understanding of star forming regions.

Accepted Answer

Spitzer, A

Question 3

Why does gravitational contraction halt in collapsing protostars?

Accepted Answer

Gravitational contraction heat

Question 4

The spectral lines of a star indicate ionized helium is prominent, yet the star appears orange in color. Explain the problem with this and offer an explanation.

Accepted Answer

Ionized helium is found only in O type s

Question 5

Why are star clusters ideal "laboratories" for stellar evolution?

Accepted Answer

A)  Their stars are all about the same age, composition, and distance from us. 
B)  Like our Sun, they lie in the plane of the Milky Way. 
C)  The combined light of all the stars makes them easier to see. 
D)  Their stars are all about the same mass and temperature. 
E)  Their stars are all the same composition and stage in evolution. 
A)  Their stars are all about the same age, composition, and distance from us. 
B)  Like our Sun, they lie in the plane of the Milky Way. 
C)  The combined light of all the stars makes them easier to see. 
D)  Their stars are all about the same mass and temperature. 
E)  Their stars are all the same composition and stage in evolution.

Question 6

How could we determine the amount of interstellar dust between us and a distant star?

Accepted Answer

The spectral lines would give us the tem

Question 7

Approximately how many brown dwarfs are believed to exist in the Milky Way galaxy?

Accepted Answer

A)  100,000 
B)  one million 
C)  one billion 
D)  one hundred billion 
E)  ten trillion 
A)  100,000 
B)  one million 
C)  one billion 
D)  one hundred billion 
E)  ten trillion

Question 8

Emission nebulae get their red color from the red supergiants forming in them.

Accepted Answer

A) True 
 B)False

Question 9

Most stars in our part of the Galaxy are formed

Accepted Answer

A)  in a singular event just after the Big Bang. 
B)  in globular clusters of millions of stars. 
C)  alone. 
D)  in associations of thousands of stars across a spiral arm of the Galaxy. 
E)  in open clusters of a few dozen. 
A)  in a singular event just after the Big Bang. 
B)  in globular clusters of millions of stars. 
C)  alone. 
D)  in associations of thousands of stars across a spiral arm of the Galaxy. 
E)  in open clusters of a few dozen.

Question 10

How does the mass of the protostar impact its future evolution?

Accepted Answer

The higher the mass, the greater its gra

Question 11

Emission nebulae are created by gas absorbing ultraviolet energy from the hot young stars within them, such as in the Orion Nebula.

Accepted Answer

A) True 
 B)False

Question 12

Dark dust clouds are optically invisible, but give off radio energy.

Accepted Answer

A) True 
 B)False

Question 13

Which statement about dark dust clouds is true?

Accepted Answer

A)  They block the vast majority of radio waves from our Galaxy. 
B)  They can be penetrated only with shorter waves, such as UV and X- ray. 
C)  Hydrogen and helium are the chief absorbing and scattering agents. 
D)  They comprise the majority of the mass of the Galaxy. 
E)  They can be penetrated only with longer wavelengths such as radio and infrared. 
A)  They block the vast majority of radio waves from our Galaxy. 
B)  They can be penetrated only with shorter waves, such as UV and X- ray. 
C)  Hydrogen and helium are the chief absorbing and scattering agents. 
D)  They comprise the majority of the mass of the Galaxy. 
E)  They can be penetrated only with longer wavelengths such as radio and infrared.

Question 14

What stage of star formation is the zero- age main sequence?

Accepted Answer

At stage 7, the zero- age main

Question 15

A cloud fragment too small to collapse into a main sequence star becomes a

Accepted Answer

A)  T- Tauri object. 
B)  brown dwarf. 
C)  white dwarf. 
D)  pulsar. 
E)  planet of another star. 
A)  T- Tauri object. 
B)  brown dwarf. 
C)  white dwarf. 
D)  pulsar. 
E)  planet of another star.

Question 16

Jupiter and the Sun have almost the same composition and density; why isn't Jupiter also a star?

Accepted Answer

Jupiter does not have enough m

Question 17

The predominant color of emission nebulae is blue.

Accepted Answer

A) True 
 B)False

Question 18

How does the interstellar gas change the light of stars passing through it, even if no dust is also present?

Accepted Answer

Even the cool, thin atoms of gas will ab

Question 19

A large gas cloud in the interstellar medium that contains several type O and B stars would appear to us as

Accepted Answer

A)  an emission nebula. 
B)  a dark nebula. 
C)  bright blue. 
D)  a dark patch against a bright background. 
E)  a reflection nebula. 
A)  an emission nebula. 
B)  a dark nebula. 
C)  bright blue. 
D)  a dark patch against a bright background. 
E)  a reflection nebula.

Question 20

Explain the colors of emission nebulae.

Accepted Answer

The predominant bright red is the emissi

The density of interstellar dust is very low, yet it still blocks starlight because

Name two telescopes that in recent years have improved our understanding of star forming regions.

Why does gravitational contraction halt in collapsing protostars?

The spectral lines of a star indicate ionized helium is prominent, yet the star appears orange in color. Explain the problem with this and offer an explanation.

Why are star clusters ideal "laboratories" for stellar evolution?

How could we determine the amount of interstellar dust between us and a distant star?

Approximately how many brown dwarfs are believed to exist in the Milky Way galaxy?

Emission nebulae get their red color from the red supergiants forming in them.

Most stars in our part of the Galaxy are formed

How does the mass of the protostar impact its future evolution?

Emission nebulae are created by gas absorbing ultraviolet energy from the hot young stars within them, such as in the Orion Nebula.

Dark dust clouds are optically invisible, but give off radio energy.

Which statement about dark dust clouds is true?

What stage of star formation is the zero- age main sequence?

A cloud fragment too small to collapse into a main sequence star becomes a

Jupiter and the Sun have almost the same composition and density; why isn't Jupiter also a star?

The predominant color of emission nebulae is blue.

How does the interstellar gas change the light of stars passing through it, even if no dust is also present?

A large gas cloud in the interstellar medium that contains several type O and B stars would appear to us as

Explain the colors of emission nebulae.

Charting the Heavens: the Foundations of Astronomy

The Copernican Revolution: the Birth of Modern Science

Light and Matter: the Inner Workings of the Cosmos

Telescopes: the Tools of Astronomy

The Solar System: Interplanetary Matter and the Birth of the Planets

Earth and Its Moon: Our Cosmic Backyard

The Terrestrial Planets: a Study in Contrasts

The Jovian Planets: Giants of the Solar System

Moons, Rings, and Plutoids: Small Worlds Among Giants

The Sun: Our Parent Star

Measuring the Stars: Giants, Dwarfs, and the Main Sequence

Stellar Evolution: the Lives and Deaths of Stars

Neutron Stars and Black Holes: Strange States of Matter

The Milky Way Galaxy: a Spiral in Space

Normal and Active Galaxies: Building Blocks of the Universe

Hubbles Law and Dark Matter: the Large-Scale Structure of the Cosmos

Cosmology: the Big Bang and the Fate of the Universe

Life in the Universe: Are We Alone

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Exam 12: The Interstellar Medium: Star Formation in the Milky Way

The density of interstellar dust is very low, yet it still blocks starlight because

Name two telescopes that in recent years have improved our understanding of star forming regions.

Why does gravitational contraction halt in collapsing protostars?

The spectral lines of a star indicate ionized helium is prominent, yet the star appears orange in color. Explain the problem with this and offer an explanation.

Why are star clusters ideal "laboratories" for stellar evolution?

How could we determine the amount of interstellar dust between us and a distant star?

Approximately how many brown dwarfs are believed to exist in the Milky Way galaxy?

Emission nebulae get their red color from the red supergiants forming in them.

Most stars in our part of the Galaxy are formed

How does the mass of the protostar impact its future evolution?

Emission nebulae are created by gas absorbing ultraviolet energy from the hot young stars within them, such as in the Orion Nebula.

Dark dust clouds are optically invisible, but give off radio energy.

Which statement about dark dust clouds is true?

What stage of star formation is the zero- age main sequence?

A cloud fragment too small to collapse into a main sequence star becomes a

Jupiter and the Sun have almost the same composition and density; why isn't Jupiter also a star?

The predominant color of emission nebulae is blue.

How does the interstellar gas change the light of stars passing through it, even if no dust is also present?

A large gas cloud in the interstellar medium that contains several type O and B stars would appear to us as

Explain the colors of emission nebulae.

Charting the Heavens: the Foundations of Astronomy

The Copernican Revolution: the Birth of Modern Science

Light and Matter: the Inner Workings of the Cosmos

Telescopes: the Tools of Astronomy

The Solar System: Interplanetary Matter and the Birth of the Planets

Earth and Its Moon: Our Cosmic Backyard

The Terrestrial Planets: a Study in Contrasts

The Jovian Planets: Giants of the Solar System

Moons, Rings, and Plutoids: Small Worlds Among Giants

The Sun: Our Parent Star

Measuring the Stars: Giants, Dwarfs, and the Main Sequence

Stellar Evolution: the Lives and Deaths of Stars

Neutron Stars and Black Holes: Strange States of Matter

The Milky Way Galaxy: a Spiral in Space

Normal and Active Galaxies: Building Blocks of the Universe

Hubbles Law and Dark Matter: the Large-Scale Structure of the Cosmos

Cosmology: the Big Bang and the Fate of the Universe

Life in the Universe: Are We Alone

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