Question 1

Which of the following is NOT a way in which astronomers detect dark matter in clusters of galaxies?
A)by determining the amount of mass necessary to gravitationally collapse clouds of gas to form the number of stars present
B)by determining the amount of mass necessary to gravitationally hold onto the hot gas surrounding galaxy clusters
C)by determining the amount of mass necessary to gravitationally hold a cluster of galaxies together
D)by determining the amount of mass necessary to gravitationally lens images of distant objects
E)None of the above;all of these are ways that astronomers detect dark matter in galaxy clusters.

Accepted Answer

Determining the amount of mass necessary to gravitationally collapse clouds of gas to form the number of stars present is not a way to detect dark matter in clusters of galaxies. This is a method to study star formation and does not relate to dark matter. The other choices are all ways that astronomers detect dark matter in galaxy clusters.

Question 2

As structure formed in the universe,galaxy-sized objects formed before cluster-sized objects.

Accepted Answer

According to current cosmological models and observations, galaxies started forming around 380,000 years after the Big Bang, while clusters of galaxies formed later through the merging of smaller structures. Therefore, galaxy-sized objects formed before cluster-sized objects.

Question 3

In clusters of galaxies,the total mass of dark matter exceeds the luminous matter by about a factor of 1,000.

Accepted Answer

False

Question 4

Which is NOT an ingredient needed to build a cosmological simulation of large-scale structure formation?
A)the spectrum of density fluctuations that quantum mechanics imprints on the early universe
B)the density of dark matter and luminous matter in the universe
C)the grand unified theory
D)the density of dark energy in the universe
E)None of the above;all of the above are necessary.

Accepted Answer

While a grand unified theory is important in understanding particle physics, it is not directly necessary for building a cosmological simulation of large-scale structure formation. The other options are all crucial components in constructing such a simulation.

Question 5

The most common type of galaxy found in a galaxy cluster is a ________ galaxy.
A)spiral
B)giant elliptical
C)giant irregular
D)dwarf
E)barred spiral

Accepted Answer

The answer of The most common type of galaxy found...

Question 6

Structure formation in our universe:
A)occurs for the largest structures first
B)occurs for the smallest structures first
C)begins on all spatial scales at the same time
D)begins after clusters form
E)begins with planets

Accepted Answer

The answer of Structure formation in our universe:
A)occurs for the...

Question 7

Which of these shows the correct order of collections of galaxies,starting with the smallest and ending with the largest?
A)group,supercluster,cluster
B)cluster,supercluster,group
C)group,cluster,supercluster
D)cluster,group,supercluster
E)supercluster,group,cluster

Accepted Answer

A galaxy group is the smallest collection of galaxies that are held together by gravity. A galaxy cluster is a larger collection of galaxy groups that are also bound by gravity. A supercluster is the largest known structure in the universe, comprising hundreds of thousands of galaxies congregated in groups and clusters. Therefore, the order of collections from smallest to largest is group, cluster, and supercluster. Choice C lists the correct order.

Question 8

Even at its earliest moments,the universe had about as much structure in it as it has at the current time.

Accepted Answer

According to current models of the universe's formation, the early universe was much less structured than it is now. It was a hot, dense, homogeneous soup of particles and radiation that gradually became more complex through gravitational interactions and other processes.

Question 9

The peculiar velocities of galaxies allow us to determine how matter is distributed in the universe.

Accepted Answer

The peculiar velocities of galaxies, which are their motions relative to the overall expansion of the universe, provide information about the distribution of matter in the universe. This can help us map the large-scale structures of the universe, such as galaxy clusters and filaments.

Question 10

If a galaxy is a member of a large cluster of galaxies,like the Coma cluster,the galaxy would have a typical velocity of 1,000 km/s.If the cluster is 10 Mpc in diameter,how long would it take the galaxy to cross from one side of the cluster to another?
A)10,000 years
B)1 million years
C)10 million years
D)100 million years
E)10 billion years

Accepted Answer

The answer of If a galaxy is a member of...

Question 11

The Local Group is a part of the Virgo Supercluster.

Accepted Answer

The Local Group is indeed a part of the Virgo Supercluster.

Question 12

What process is most responsible for shaping the large-scale structure of the universe?
A)supernovae from the first generation of stars
B)gravity
C)matter/antimatter annihilation
D)magnetic fields
E)electric force

Accepted Answer

Gravity is the dominant force responsible for shaping the large-scale structure of the universe, pulling matter together to form galaxies, galaxy clusters, and superclusters. While other forces such as supernovae and matter/antimatter annihilation play a role in shaping the universe, they are not as significant as gravity on the large scale. Magnetic fields and electric force are also not strong enough to have a significant impact on the large-scale structure of the universe.

Question 13

Astronomers have determined that the Milky Way is being pulled toward a massive structure called the "Great Attractor" due to the mass of the Great Attractor alone.

Accepted Answer

The answer of Astronomers have determined that the Milky Way...

Question 14

Peculiar velocities are produced by:
A)erroneous redshifts
B)gravity
C)supernovae
D)eclipsing binary stars
E)interstellar winds

Accepted Answer

Peculiar velocities are produced by the gravitational pull of nearby objects, causing a deviation from the expected redshift. This is known as the "redshift-space distortion" effect. The other options do not contribute significantly to the production of peculiar velocities.

Question 15

What does the large-scale structure of the universe look most like?
A)a sponge with many large holes
B)a loaf of wheat bread with many tiny holes
C)a plate of flat noodles
D)a jar of marbles
E)a pizza with evenly spread out pepperoni

Accepted Answer

The large-scale structure of the universe looks like a sponge with many large holes. This is due to the distribution of galaxy clusters and voids, forming a complex and interconnected network resembling a sponge.

Question 16

Which of these components makes up the largest amount of mass in a typical large cluster of galaxies?
A)supermassive black holes
B)stars
C)cold gas
D)hot gas
E)neutron and white dwarf stars

Accepted Answer

The hot gas in a typical large cluster of galaxies makes up the largest amount of mass, as it fills the space between galaxies and can be detected through X-ray observations.

Question 17

The first stars formed in the universe did not require the effects of dark matter to form.

Accepted Answer

The answer of The first stars formed in the universe...

Question 18

There are fluctuations in the CMB due to the fact that clumps of dark matter had already begun to form in the universe when the light from the CMB was given off.

Accepted Answer

The fluctuations in the CMB are indeed due to the presence of clumps of dark matter in the early universe. These clumps affected the distribution of matter and energy in the early universe, which is reflected in the observed fluctuations in the CMB.

Question 19

We currently find ourselves in the stelliferous era in the history of our universe.

Accepted Answer

The stelliferous era, also known as the galactic era, is the current era in which the majority of matter in the universe is organized into galaxies, many of which contain stars. It began around 13.6 billion years ago and is expected to continue until around 100 trillion years into the future.

Question 20

Current theoretical models suggest that most of the universe is composed of hot dark matter.

Accepted Answer

Current theoretical models propose that most of the universe is composed of cold dark matter, rather than hot dark matter.

Quiz 23: Large-Scale Structure in the Universe

Which of the following is NOT a way in which astronomers detect dark matter in clusters of galaxies?

As structure formed in the universe,galaxy-sized objects formed before cluster-sized objects.

In clusters of galaxies,the total mass of dark matter exceeds the luminous matter by about a factor of 1,000.

Which is NOT an ingredient needed to build a cosmological simulation of large-scale structure formation?

The most common type of galaxy found in a galaxy cluster is a ________ galaxy.

Structure formation in our universe:

Which of these shows the correct order of collections of galaxies,starting with the smallest and ending with the largest?

Even at its earliest moments,the universe had about as much structure in it as it has at the current time.

The peculiar velocities of galaxies allow us to determine how matter is distributed in the universe.

If a galaxy is a member of a large cluster of galaxies,like the Coma cluster,the galaxy would have a typical velocity of 1,000 km/s.If the cluster is 10 Mpc in diameter,how long would it take the galaxy to cross from one side of the cluster to another?

The Local Group is a part of the Virgo Supercluster.

What process is most responsible for shaping the large-scale structure of the universe?

Astronomers have determined that the Milky Way is being pulled toward a massive structure called the "Great Attractor" due to the mass of the Great Attractor alone.

Peculiar velocities are produced by:

What does the large-scale structure of the universe look most like?

Which of these components makes up the largest amount of mass in a typical large cluster of galaxies?

The first stars formed in the universe did not require the effects of dark matter to form.

There are fluctuations in the CMB due to the fact that clumps of dark matter had already begun to form in the universe when the light from the CMB was given off.

We currently find ourselves in the stelliferous era in the history of our universe.

Current theoretical models suggest that most of the universe is composed of hot dark matter.