Question 1

What is the Hubble constant essentially a measure of?

Accepted Answer

The Hubble constant is a measure of the rate at which the universe is expanding. It relates the distance between galaxies to their relative velocities, and its value is used to determine the age and size of the universe.

Question 2

An elliptical galaxy could

Accepted Answer

Elliptical galaxies are believed to form from the collision and merger of smaller galaxies. This would be the most likely way for a spiral galaxy to evolve into an elliptical galaxy. The other options are not consistent with current understanding of galaxy evolution.

Question 3

What distance method is used to determine the distance to the most distant galaxies when only a redshift is measured?

Accepted Answer

Hubble's law relates the redshift of a galaxy to its distance, allowing us to determine the distance to the most distant galaxies even when only a redshift is measured.

Question 4

The Virgo cluster

Accepted Answer

The Virgo cluster is a rich galactic cluster and is the closest cluster of galaxies located outside of the Local Group. It contains mostly spiral galaxies and very few elliptical galaxies. It is not the galactic cluster that contains the Milky Way, the oldest known cluster of galaxies, or located at the center of the universe.

Question 5

If the absolute magnitude, M , of a supernova is − 19 and a galaxy is found that contains a supernova with an apparent magnitude, m , of 16. What is the distance to the galaxy? Hint: d _pc = 10^{( m - M + 5)/5}

Accepted Answer

Using the distance modulus formula: d_pc = 10^((m - M + 5)/5), we substitute m = 16 and M = -19 to get d_pc = 10^((16 - (-19) + 5)/5) = 10^(40/5) = 10^8 pc, which is equivalent to 100 Mpc.

Question 6

What of the following distance methods is used to determine the distance to the most distant galaxies?

Accepted Answer

Supernova observations, specifically of Type Ia supernovae, are used to determine the distance to the most distant galaxies. These supernovae have a known luminosity, allowing astronomers to calculate their distance based on their apparent brightness.

Question 7

What is the primary factor in determining the classification for an elliptical galaxy?

Accepted Answer

The primary factor in determining the classification for an elliptical galaxy is its shape, which is based on its eccentricity or the ratio of the major axis to the minor axis. Elliptical galaxies range from E0 (nearly circular) to E7 (highly elongated), and this classification system is widely used by astronomers. While size, mass, and color can provide additional information about an elliptical galaxy, they are not the primary factor in determining its classification.

Question 8

Starburst galaxies

Accepted Answer

Starburst galaxies are often associated with a galaxy that is colliding with another galaxy. This interaction triggers a burst of star formation as gas is compressed and ignited. Starburst galaxies contain a large number of young stars and gas clouds as a result of this recent burst of formation. Options A and B are incorrect as they describe galaxies that do not have the characteristics of a starburst galaxy. Option D is incorrect as starburst galaxies are typically found in lower density environments. Option E is incorrect as it describes the large-scale structure of the universe, not individual galaxies.

Question 9

Of the following, which of the following is the largest object?

Accepted Answer

The Local Group is the largest object among the options listed, as it is a galaxy group that contains both the Milky Way and the Andromeda Galaxy, along with the Large Magellanic Cloud and numerous other smaller galaxies.

Question 10

The letters AGN stand for

Accepted Answer

AGN stands for Active Galaxy Nucleus, which refers to a region at the center of a galaxy that emits a large amount of energy across the electromagnetic spectrum. This energy is believed to originate from supermassive black holes that are accreting matter and producing powerful jets of particles. AGN are vastly different from active stars and planets, making options A, B, and C incorrect.

Question 11

What type of galaxies do astronomers believe to be the most common?

Accepted Answer

Elliptical galaxies are believed to be the most common type in the universe, especially in more densely populated regions of space like galaxy clusters.

Question 12

Supermassive black holes are believed to be located at the center of many galaxies because

Accepted Answer

The orbital motion of material near the center of a galaxy, such as stars or gas, can indicate the presence of a very massive object. This is because the mass of the object affects the gravitational forces on the orbiting material, which in turn affects its motion. The observed fast orbital motion near the center of many galaxies suggests the presence of a very massive object, such as a supermassive black hole.

Question 13

It is believed that ring galaxies form

Accepted Answer

The answer of It is believed that ring galaxies form
...

Question 14

The Milky Way galaxy is part of

Accepted Answer

The Milky Way is part of the Local Group, which is a cluster of about 54 galaxies that includes the Milky Way and its neighboring galaxies such as Andromeda and the Triangulum Galaxy. The Virgo cluster is another galaxy cluster, but it is much farther away from the Local Group. The Large and Small Magellanic Clouds are satellite galaxies of the Milky Way, not clusters or groups of galaxies.

Question 15

What factors are important when trying to classify a spiral galaxy?

Accepted Answer

All of the factors listed are important when classifying a spiral galaxy. The amount of dust and gas in the galaxy can affect the formation and appearance of the spiral arms, which are also crucial in classification. Additionally, the size of the central region can also give insight into the overall structure of the galaxy. Therefore, all of the choices are important in the classification of spiral galaxies.

Question 16

If H equals 70 km/s/Mpc, then a galaxy with a radial velocity of 2100 km/s has a distance of approximately

Accepted Answer

The Hubble Law states that the velocity of a galaxy (v) is equal to the Hubble constant (H) times its distance (d), or v = Hd. To find the distance, rearrange the equation to d = v/H. Substituting the given values, d = 2100 km/s / 70 km/s/Mpc = 30 Mpc.

Question 17

Observations of galaxies and clusters of galaxies indicate that about ___________ percent of the matter in the universe is dark matter.

Accepted Answer

The answer of Observations of galaxies and clusters of galaxies...

Question 18

If Galaxy A is found to have a recessional velocity four times greater than Galaxy B, what can you say about their relative distances from Earth?

Accepted Answer

According to Hubble's law, the recessional velocity of a galaxy is directly proportional to the distance of the galaxy from Earth. Therefore, if Galaxy A has a velocity four times greater than Galaxy B, it means that Galaxy A is four times further away than Galaxy B.

Question 19

If a galaxy has a radial velocity of 8000 km/s and the Hubble constant is 70 km/s/Mpc, what is the distance to this galaxy?

Accepted Answer

The distance to the galaxy can be calculated using Hubble's Law: distance = velocity / Hubble constant. So, 8000 km/s divided by 70 km/s/Mpc equals 114 Mpc.

Question 20

What distance method did Edwin Hubble use to determine the distance to local galaxies?

Accepted Answer

Edwin Hubble used the period-luminosity relationship of variable stars, specifically Cepheid variables, to determine the distance to local galaxies. This relationship allows astronomers to determine the intrinsic brightness of a star based on its apparent brightness and period of variability, which can then be used to calculate its distance from Earth.

Quiz 13: Galaxies: Normal and Active

What is the Hubble constant essentially a measure of?

An elliptical galaxy could

What distance method is used to determine the distance to the most distant galaxies when only a redshift is measured?

The Virgo cluster

If the absolute magnitude, M , of a supernova is − 19 and a galaxy is found that contains a supernova with an apparent magnitude, m , of 16. What is the distance to the galaxy? Hint: d _pc = 10^{( m - M + 5) /5}

What of the following distance methods is used to determine the distance to the most distant galaxies?

What is the primary factor in determining the classification for an elliptical galaxy?

Starburst galaxies

Of the following, which of the following is the largest object?

The letters AGN stand for

What type of galaxies do astronomers believe to be the most common?

Supermassive black holes are believed to be located at the center of many galaxies because

It is believed that ring galaxies form

The Milky Way galaxy is part of

What factors are important when trying to classify a spiral galaxy?

If H equals 70 km/s/Mpc, then a galaxy with a radial velocity of 2100 km/s has a distance of approximately

Observations of galaxies and clusters of galaxies indicate that about ___________ percent of the matter in the universe is dark matter.

If Galaxy A is found to have a recessional velocity four times greater than Galaxy B, what can you say about their relative distances from Earth?

If a galaxy has a radial velocity of 8000 km/s and the Hubble constant is 70 km/s/Mpc, what is the distance to this galaxy?

What distance method did Edwin Hubble use to determine the distance to local galaxies?

Quiz 13: Galaxies: Normal and Active

What is the Hubble constant essentially a measure of?

An elliptical galaxy could

What distance method is used to determine the distance to the most distant galaxies when only a redshift is measured?

The Virgo cluster

If the absolute magnitude, M , of a supernova is − 19 and a galaxy is found that contains a supernova with an apparent magnitude, m , of 16. What is the distance to the galaxy? Hint: d pc = 10( m - M + 5) /5

What of the following distance methods is used to determine the distance to the most distant galaxies?

What is the primary factor in determining the classification for an elliptical galaxy?

Starburst galaxies

Of the following, which of the following is the largest object?

The letters AGN stand for

What type of galaxies do astronomers believe to be the most common?

Supermassive black holes are believed to be located at the center of many galaxies because

It is believed that ring galaxies form

The Milky Way galaxy is part of

What factors are important when trying to classify a spiral galaxy?

If H equals 70 km/s/Mpc, then a galaxy with a radial velocity of 2100 km/s has a distance of approximately

Observations of galaxies and clusters of galaxies indicate that about ___________ percent of the matter in the universe is dark matter.

If Galaxy A is found to have a recessional velocity four times greater than Galaxy B, what can you say about their relative distances from Earth?

If a galaxy has a radial velocity of 8000 km/s and the Hubble constant is 70 km/s/Mpc, what is the distance to this galaxy?

What distance method did Edwin Hubble use to determine the distance to local galaxies?

If the absolute magnitude, M , of a supernova is − 19 and a galaxy is found that contains a supernova with an apparent magnitude, m , of 16. What is the distance to the galaxy? Hint: d _pc = 10^{( m - M + 5) /5}