Question 1

A nearby galaxy has a radius of 4,000 million A.U. and rotates once every 800 million years.What is its mass in solar masses?

Accepted Answer

Using Kepler's third law, $\mathrm { P } ^ { 2 } = \mathrm { a } ^ { 3 } / ( \mathrm { M } + \mathrm { m } )$ nd using solar system units of years,A.U.s, and solar masses, the sum of the masses must be M + m = $10^{11}$ solar masses. The sum ofthe masses, in this case represents the total mass of the galaxy.

Question 2

Giant elliptical galaxies may be the result of ________ in the centers of rich clusters.

Accepted Answer

galaxy mergers (or cannibalism)

Question 3

How do head-tail radio galaxies reveal their motion?

Accepted Answer

Their bipolar jets shock the intergalactic medium and trail behind the moving galaxylike the wake of a boat.

Question 4

In its most energetic phase, a quasar can probably only last:

Accepted Answer

A) a few days. 
B) a few years. 
C) a few thousand years. 
D) a few million years. 
E) a few billion years. 
A) a few days. 
B) a few years. 
C) a few thousand years. 
D) a few million years. 
E) a few billion years.

Question 5

Galaxies contain at most one supermassive black hole.

Accepted Answer

A) True 
 B)False

Question 6

What evidence has Chandra found to contradict the hypothesis that black holes merge duringgalaxy collisions?

Accepted Answer

A) a double black hole in a single galaxy 
B) a black hole without a host galaxy 
C) a hypermassive black hole 
D) a triple black hole system 
E) a dwarf galaxy containing a black hole 
A) a double black hole in a single galaxy 
B) a black hole without a host galaxy 
C) a hypermassive black hole 
D) a triple black hole system 
E) a dwarf galaxy containing a black hole

Question 7

Why would galaxies colliding in a small cluster tend to stick together, while galaxies in alarge cluster tend to pass through each other?

Accepted Answer

In a small cluster the lower mass means

Question 8

Distant galaxies tend to be much bluer than those nearby.

Accepted Answer

A) True 
 B)False

Question 9

Explain the significance of the Lyman Alpha Forest in studying the universe on the grandestof scales.

Accepted Answer

While the Lyman alpha line would normall

Question 10

The huge, dark, almost spherical regions between the superclusters of galaxies are called________.

Accepted Answer

The answer of The huge, dark, almost spherical regions between...

Question 11

Which of these is NOT considered a fine example of galactic collisions?

Accepted Answer

A) the Cartwheel Galaxy 
B) the Antennae Galaxies 
C) the Whirlpool Galaxy 
D) M-31 in Andromeda 
E) M-87 in Virgo 
A) the Cartwheel Galaxy 
B) the Antennae Galaxies 
C) the Whirlpool Galaxy 
D) M-31 in Andromeda 
E) M-87 in Virgo

Question 12

Why did the quasar epoch end?

Accepted Answer

Mergers declined and

Question 13

Vast majority of the known volume of the universe lies in the voids.

Accepted Answer

A) True 
 B)False

Question 14

Contrast the results of a collision between two spiral galaxies on their stars and their gas anddust clouds.

Accepted Answer

The stars are so spread out that collisi

Question 15

That we can see two images of the same quasar is due to a(n)________ lens formed by amassive galaxy lying in front of the quasar.

Accepted Answer

The answer of That we can see two images of...

Question 16

In a collision between clusters of galaxies, what happens to the hot gas and dark matter,based on observations of the "bullet cluster"?

Accepted Answer

A) The gas stays with the luminous matter, but the dark matter moves on. 
B) The dark matter stays with the luminous matter, but the gas moves on. 
C) Both the dark matter and gas continue their motion, leaving behind the luminous portions ofthe galaxies. 
D) The luminous matter moves on, leaving behind the dark matter and gas. 
E) The dark matter moves with the luminous matter, leaving behind the gas. 
A) The gas stays with the luminous matter, but the dark matter moves on. 
B) The dark matter stays with the luminous matter, but the gas moves on. 
C) Both the dark matter and gas continue their motion, leaving behind the luminous portions ofthe galaxies. 
D) The luminous matter moves on, leaving behind the dark matter and gas. 
E) The dark matter moves with the luminous matter, leaving behind the gas.

Question 17

Gas that has never been cycled through a galaxy or a star is said to be ________.

Accepted Answer

The answer of Gas that has never been cycled through...

Question 18

Why do we believe galaxy clusters are rich in dark matter?

Accepted Answer

Studies of the gravitational i

Question 19

Careful observations of nearby normal and active galaxies reveal that the mass of the centralblack hole is well correlated with the mass of the galactic bulge. The ratio of bulge mass to blackhole mass is roughly:

Accepted Answer

A) 1 to 2000. 
B) 1 to 200. 
C) 1 to 20. 
D) 20 to 1. 
E) 200 to 1. 
A) 1 to 2000. 
B) 1 to 200. 
C) 1 to 20. 
D) 20 to 1. 
E) 200 to 1.

Question 20

While quasars may have now vanished, the large black holes they formed are still around,just not being fed as well any more.

Accepted Answer

A) True 
 B)False

Exam 25: Galaxies and Dark Matter: The Large-Scale Structure of the Cosmos

A nearby galaxy has a radius of 4,000 million A.U. and rotates once every 800 million years.What is its mass in solar masses?

Giant elliptical galaxies may be the result of ________ in the centers of rich clusters.

How do head-tail radio galaxies reveal their motion?

In its most energetic phase, a quasar can probably only last:

Galaxies contain at most one supermassive black hole.

What evidence has Chandra found to contradict the hypothesis that black holes merge duringgalaxy collisions?

Why would galaxies colliding in a small cluster tend to stick together, while galaxies in alarge cluster tend to pass through each other?

Distant galaxies tend to be much bluer than those nearby.

Explain the significance of the Lyman Alpha Forest in studying the universe on the grandestof scales.

The huge, dark, almost spherical regions between the superclusters of galaxies are called________.

Which of these is NOT considered a fine example of galactic collisions?

Why did the quasar epoch end?

Vast majority of the known volume of the universe lies in the voids.

Contrast the results of a collision between two spiral galaxies on their stars and their gas anddust clouds.

That we can see two images of the same quasar is due to a(n)________ lens formed by amassive galaxy lying in front of the quasar.

In a collision between clusters of galaxies, what happens to the hot gas and dark matter,based on observations of the "bullet cluster"?

Gas that has never been cycled through a galaxy or a star is said to be ________.

Why do we believe galaxy clusters are rich in dark matter?

Careful observations of nearby normal and active galaxies reveal that the mass of the centralblack hole is well correlated with the mass of the galactic bulge. The ratio of bulge mass to blackhole mass is roughly:

While quasars may have now vanished, the large black holes they formed are still around,just not being fed as well any more.

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: Earths 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

The Interstellar Medium: Gas and Dust Among the Stars

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

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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