01
True or false
1 point
Dark matter is inferred from its gravitational effects rather than observed through light it emits or reflects. Is this statement true or false?
Free Practice Quiz Question List
7 Dark Matter and Cosmic Structure Online Quiz Questions
Use this free practice quiz with 20 questions to review 7 Dark Matter and Cosmic Structure, test your knowledge, and prepare for your next test or exam.
20 questions
02
Choose one
1 point
Far from the centers of many spiral galaxies, what do observed orbital speeds suggest about how mass is distributed?
- A
The rotation speed falls sharply, showing that nearly all mass is concentrated in visible stars.
- B
The rotation speed remains roughly constant, suggesting an extended halo of unseen mass.
- C
The rotation speed becomes zero beyond the visible edge of the galaxy.
- D
The rotation speed proves that stars do not orbit the galaxy's center.
03
Written response
1 point
What is the name for the vast structure of filaments and voids within which galaxies and clusters form?
04
Choose one
1 point
How can astronomers use gravitational lensing to estimate the mass of a galaxy or galaxy cluster?
- A
By measuring how much light a cluster emits
- B
By counting only the visible stars in a galaxy
- C
By measuring how gravity distorts images of more distant objects
- D
By measuring how quickly hot gas cools
05
True or false
1 point
In the Bullet Cluster, much of the hot ordinary gas was slowed and displaced during the collision, while the lensing-inferred mass remained concentrated near the galaxies. Is this statement true or false?
- A
True
- B
False
06
Written response
1 point
What is the name of the relic light from the early universe whose measured patterns fit a universe containing dark matter?
07
Choose one
1 point
According to the leading model, which sequence best describes how ordinary matter began forming stars and galaxies?
- A
Stars formed first, and their gravity later created dark matter halos.
- B
Gas gathered in halos after atoms formed, allowing stars and galaxies to develop.
- C
Clusters formed before galaxies, and then produced the cosmic microwave background.
- D
The cosmic web formed from gas before dark matter began to clump.
08
Choose all
1 point
Which observations are cited as evidence supporting dark matter? Select all that apply.
- A
The roughly constant rotation speeds far from many spiral galaxy centers
- B
Lensing distortions that indicate more mass than visible matter accounts for
- C
The color of visible stars in a galaxy
- D
Patterns in the cosmic microwave background
09
Choose all
1 point
Which of these are hypothetical particle candidates proposed as possible dark matter? Select all that apply.
- A
WIMPs
- B
Axions
- C
Primordial black holes
- D
Ordinary hot gas
10
Open ended
1 point
Explain how dark matter halos help ordinary matter develop into stars, galaxies, and larger cosmic structures. Include the role of gas and the later merging of smaller structures.
11
Choose one
1 point
Modified-gravity ideas can explain some galaxy observations. Why does dark matter nevertheless remain the central explanation in the standard cosmological model?
- A
Modified gravity explains every observation better than dark matter does.
- B
Dark matter has been directly observed emitting light from galaxy halos.
- C
Dark matter also accounts for evidence from lensing, galaxy clusters, the cosmic microwave background, and large-scale structure.
- D
Modified gravity is not considered in any scientific models.
12
Written response
1 point
What is the name for hypothetical black holes formed in the early universe that have been investigated as a possible explanation for dark matter?
13
Choose one
1 point
In a spiral galaxy, stars far from the center keep orbiting at roughly the same speed as stars closer in. What does this observation most strongly suggest?
- A
Most of the galaxy’s mass is concentrated in its visible center.
- B
An extended halo contains unseen mass beyond the visible stars and gas.
- C
The galaxy’s stars are not moving under the influence of gravity.
- D
Dark energy is pulling the stars into circular orbits.
14
Choose one
1 point
A model must explain both the growth of galaxies and the accelerated expansion of the universe. Which statement correctly distinguishes dark matter from dark energy?
- A
Dark matter helps matter clump and form structure; dark energy is associated with accelerated expansion.
- B
Dark matter causes accelerated expansion; dark energy gathers gas into halos.
- C
Both terms refer to the unseen mass inferred from galaxy rotation.
- D
Dark matter and dark energy are two names for cold dark matter.
15
Choose one
1 point
After two galaxy clusters collide, observations show that much of their hot gas has been slowed and displaced, but gravitational lensing places much of the mass near the galaxies. What is the strongest inference from this contrast?
- A
The lensing signal follows the displaced gas, showing that all the mass is ordinary gas.
- B
The galaxies contain no mass, so lensing cannot reveal anything about the collision.
- C
The lensing-inferred mass stays near the galaxies while much of the gas is displaced, supporting matter that interacts less with ordinary matter than the gas does.
- D
The collision proves that dark energy is concentrated inside galaxy clusters.
16
Choose one
1 point
Which sequence best describes how dark matter helps structure form in the leading cosmological model?
- A
Stars form first, then their light creates dark matter halos that attract gas.
- B
Dark matter clumps into halos, gas gathers in them after atoms form, and stars and galaxies develop.
- C
Gas forms galaxies before dark matter begins to clump, and the halos later stop structure from growing.
- D
Dark matter remains evenly spread, while dark energy gathers gas into halos.
17
True or false
1 point
True or false: Patterns in the cosmic microwave background and the observed distribution of galaxies and clusters both support models in which dark matter helps structure grow.
- A
True
- B
False
18
Written response
1 point
Astronomers estimate the mass of a galaxy cluster by measuring how its gravity distorts images of more distant objects. What is this method called?
19
Fill in the blank
1 point
In the leading cosmological model, cold dark matter moved enough for gravity to pull it into clumps as the universe evolved.
20
Fill in the blank
1 point
A model describes dark matter moving slowly enough for gravity to gather it into . What word completes this description?