Question Set on Dark Matter, Dark Energy, and the Mysterious
Components of the Universe
1. What percentage of the universe is believed to be composed of dark energy?
a) 68%
b) 27%
c) 5%
d) 95%
Answer: a
2. What percentage of the universe is estimated to be dark matter?
a) 68%
b) 27%
c) 5%
d) 95%
Answer: b
3. What is the primary evidence for the existence of dark matter?
a) Galactic rotation curves
b) Cosmic microwave background
c) Supernovae observations
d) Black hole observations
Answer: a
4. Which of the following is NOT a proposed candidate for dark matter?
a) WIMPs
b) Axions
c) Neutrinos
d) Photons
Answer: d
5. What is the main effect attributed to dark energy?
a) Gravitational lensing
b) Accelerating expansion of the universe
c) Formation of galaxy clusters
d) Cosmic inflation
Answer: b
6. Which observation led to the discovery of dark energy?
a) Galactic rotation curves
b) Cosmic microwave background anisotropies
c) Type Ia supernovae
d) Gravitational waves
Answer: c
7. What is the ΛCDM model?
a) A theory of dark matter composition
b) The standard model of Big Bang cosmology
c) A model of galaxy formation
d) A theory of quantum gravity
Answer: b
8. What does the cosmological constant Λ represent in general relativity?
a) The curvature of spacetime
b) The energy density of empty space
c) The rate of universe expansion
d) The strength of gravity
Answer: b
9. Which of the following is NOT a method used to detect dark matter?
a) Direct detection experiments
b) Indirect detection through annihilation products
c) Particle collider experiments
d) Observations of black hole mergers
Answer: d
10. What is the "cuspy halo problem" in dark matter research?
a) A discrepancy between predicted and observed dark matter distribution in galaxies
b) The difficulty in detecting dark matter particles
c) The mystery of dark matter's composition
d) The challenge of simulating dark matter in computer models
Answer: a
11. Which particle physics theory proposes a candidate for dark matter?
a) Standard Model
b) Supersymmetry
c) String Theory
d) Quantum Chromodynamics
Answer: b
12. What is the "bullet cluster" and why is it significant?
a) A galaxy cluster providing strong evidence for dark matter
b) A type of supernova used to measure cosmic expansion
c) A region of space with high dark energy density
d) A black hole at the center of our galaxy
Answer: a
13. What is the "cosmic web"?
a) The large-scale structure of the universe
b) A theory of dark energy
c) The network of cosmic rays in space
d) The fabric of spacetime
Answer: a
14. Which of the following is a proposed explanation for dark energy?
a) Modified gravity theories
b) Supersymmetric particles
c) Primordial black holes
d) Cosmic strings
Answer: a
15. What is the "core-cusp problem" in dark matter research?
a) A discrepancy between simulated and observed dark matter density profiles
b) The difficulty in detecting dark matter in galaxy cores
c) The mystery of dark matter's interaction with normal matter
d) The challenge of explaining dark matter's effect on galaxy rotation
Answer: a
16. What is the "missing satellite problem"?
a) A discrepancy between predicted and observed number of dwarf galaxies
b) The lack of dark matter in satellite galaxies
c) The difficulty in detecting dark matter in the Milky Way's satellites
d) The absence of satellitesaround some galaxies
Answer: a
17. Which of the following is NOT a property typically attributed to dark matter?
a) Non-baryonic
b) Weakly interacting
c) Cold (non-relativistic)
d) Electromagnetically charged
Answer: d
18. What is the "cosmic coincidence problem"?
a) The similar densities of dark matter and dark energy in the present era
b) The unexplained correlation between galaxy sizes and dark matter halos
c) The mysterious alignment of cosmic microwave background anisotropies
d) The unexpected uniformity of the universe on large scales
Answer: a
19. Which space mission provided precise measurements of the cosmic microwave
background?
a) Hubble Space Telescope
b) Chandra X-ray Observatory
c) Planck satellite
d) James Webb Space Telescope
Answer: c
20. What is the "baryonic acoustic oscillation" (BAO) and how is it related to dark matter?
a) Sound waves in the early universe, influenced by dark matter's gravitational effects
b) Oscillations in dark matter density
c) Vibrations of baryonic matter caused by dark energy
d) Fluctuations in the cosmic microwave background
Answer: a
21. What is the "WIMP miracle"?
a) The coincidence that WIMP properties could explain dark matter abundance
b) The unexpected detection of WIMPs in laboratories
c) The theory that WIMPs can solve all cosmological problems
d) The discovery of WIMP annihilation in galaxy centers
Answer: a
22. Which of the following experiments is designed to directly detect dark matter particles?
a) LIGO
b) XENON
c) IceCube
d) BICEP
Answer: b
23. What is the "cosmic web" primarily composed of?
a) Dark matter and galaxies
b) Dark energy
c) Intergalactic medium
d) Cosmic rays
Answer: a
24. What is the "void problem" in cosmology?
a) The observation that cosmic voids are emptier than predicted by ΛCDM model
b) The difficulty in detecting voids in the cosmic web
c) The mystery of how voids form in the universe
d) The challenge of simulating void evolution in computer models
Answer: a
25. Which of the following is NOT a proposed solution to the dark energy problem?
a) Quintessence
b) Modified gravity
c) Cosmological constant
d) Supersymmetric dark matter
Answer: d
26. What is the "chameleon mechanism" in the context of modified gravity theories?
a) A way for modified gravity to pass solar system tests while affecting cosmological scales
b) The ability of dark matter to change its properties in different environments
c) A proposed interaction between dark matter and dark energy
d) A method for dark energy to vary its density over time
Answer: a
27. What is the "cosmological principle"?
a) The universe is homogeneous and isotropic on large scales
b) The laws of physics are the same everywhere in the universe
c) The universe is expanding at an accelerating rate
d) Dark matter and dark energy dominate the universe's composition
Answer: a
28. Which of the following is a key prediction of the ΛCDM model?
a) The existence of cosmic strings
b) The presence of a cosmic web structure
c) The dominance of hot dark matter
d) The deceleration of cosmic expansion
Answer: b
29. What is the "cosmic variance" in cosmology?
a) The statistical uncertainty in observations due to the finite observable universe
b) The variation in cosmic microwave background temperature
c) The difference between local and global measurements of cosmic parameters
d) The fluctuation in dark energy density across the universe
Answer: a
30. Which of the following is NOT a method used to map the distribution of dark matter?
a) Gravitational lensing
b) Galaxy cluster dynamics
c) Cosmic microwave background anisotropies
d) Neutrino oscillations
Answer: d
31. What is the "Sachs-Wolfe effect"?
a) The gravitational redshift of CMB photons due to large-scale structure
b) The bending of light by dark matter halos
c) The acceleration of cosmic expansion due to dark energy
d) The formation of galaxies in dark matter potential wells
Answer: a
32. Which of the following is a proposed alternative to particle dark matter?
a) Modified Newtonian Dynamics (MOND)
b) Supersymmetry
c) Axions
d) Sterile neutrinos
Answer: a
33. What is the "cosmic triangle" in cosmology?
a) A diagram representing the relative densities of matter, dark energy, and curvature
b) The three main components of the standard cosmological model
c) The relationship between Hubble constant, matter density, and dark energy
d) The connection between inflation, dark matter, and dark energy
Answer: a
34. What is the "Alcock-Paczynski test" used for in cosmology?
a) Constraining cosmological parameters using galaxy clustering
b) Detecting dark matter particles
c) Measuring the expansion rate of the universe
d) Testing modified gravity theories
Answer: a
35. Which of the following is NOT a property typically associated with dark energy?
a) Negative pressure
b) Uniform distribution
c) Time-varying density
d) Gravitational attraction
Answer: d
36. What is the "cosmic shear" effect?
a) The distortion of galaxy shapes due to weak gravitational lensing
b) The stretching of space due to cosmic expansion
c) The bending of light by massive galaxy clusters
d) The variation in cosmic microwave background temperature
Answer: a
37. What is the "Lyman-alpha forest" and how is it related to dark matter?
a) Absorption lines in quasar spectra tracing the cosmic web
b) A region of space with high dark matter density
c) A type of galaxy formation influenced by dark matter
d) A method for directly detecting dark matter particles
Answer: a
38. What is the "tensor-to-scalar ratio" r in cosmology?
a) A measure of primordial gravitational waves from inflation
b) The ratio of dark matter to dark energy in the universe
c) The proportion of baryonic to non-baryonic matter
d) The relationship between cosmic expansion and structure formation
Answer: a
39. Which of the following is NOT a proposed dark energy model?
a) Phantom energy
b) Quintessence
c) Chameleon fields
d) Warm dark matter
Answer: d
40. What is the "integrated Sachs-Wolfe effect"?
a) The late-time effect of dark energy on CMB photons
b) The total mass of dark matter in galaxy clusters
c) The combined effect of dark matter and baryons on structure formation
d) The integrated history of cosmic reionization
Answer: a
41. Calculate the critical density of the universe given H0 = 70 km/s/Mpc. (Use G = 6.67 × 10^-
11 m^3 kg^-1 s^-2)
a) 9.47 × 10^-27 kg/m^3
b) 1.88 × 10^-26 kg/m^3
c) 3.76 × 10^-27 kg/m^3
d) 5.64 × 10^-26 kg/m^3
Answer: a
42. If the dark energy equation of state is w = -1.05, what is the dark energy density ρDE as a
function of scale factor a, given ρDE,0 is the current dark energy density?
a) ρDE = ρDE,0 a^-3.15
b) ρDE = ρDE,0 a^3.15
c) ρDE = ρDE,0 a^-0.15
d) ρDE = ρDE,0 a^0.15
Answer: a
43. In a flat ΛCDM universe with ΩM = 0.3, what is the value of ΩΛ?
a) 0.3
b) 0.5
c) 0.7
d) 1.0
Answer: c
44. If the current matter density (including dark matter) is 3 × 10^-27 kg/m^3, what is the
corresponding density parameter ΩM? (Use the result from question 41 for critical density)
a) 0.2
b) 0.3
c) 0.4
d) 0.5
Answer: b
45. Calculate the age of the universe in a matter-dominated (ΩM = 1) universe with H0 = 70
km/s/Mpc.
a) 9.3 billion years
b) 13.8 billion years
c) 18.5 billion years
d) 27.6 billion years
Answer: a
46. If dark matter makes up 85% of the matter in a galaxy with total mass 10^12 solar masses,
what is the mass of dark matter in the galaxy?
a) 8.5 × 10^11 solar masses
b) 1.5 × 10^11 solar masses
c) 5.0 × 10^11 solar masses
d) 1.0 × 10^12 solar masses
Answer: a
47. Calculate the Schwarzschild radius of a primordial black hole with mass equal to the Earth's
mass (5.97 × 10^24 kg).
a) 8.87 mm
b) 1.77 cm
c) 3.54 cm
d) 7.08 cm
Answer: a
48. If the dark energy density remains constant while matter density decreases as a^-3, at what
redshift z will the dark energy density equal the matter density? (Assume current ΩM = 0.3 and
ΩΛ = 0.7)
a) z = 0.33
b) z = 0.67
c) z = 1.00
d) z = 1.33
Answer: a
49. Calculate the comoving distance to a galaxy at redshift z = 1 in a flat ΛCDM universe with
H0 = 70 km/s/Mpc, ΩM = 0.3, and ΩΛ = 0.7.
a) 3.3 Gpc
b) 4.2 Gpc
c) 5.1 Gpc
d) 6.0 Gpc
Answer: a
50. If the WIMP-nucleon cross-section is 10^-46 cm^2, what is the expected event rate
(events/kg/day) in a direct detection experiment, assuming a local dark matter density of 0.3
GeV/cm^3 and average WIMP velocity of 220 km/s?
a) 0.1 events/kg/day
b) 0.01 events/kg/day
c) 0.001 events/kg/day
d) 0.0001 events/kg/day
Answer: c
51. What is the "cosmic microwave background" (CMB)?
a) Radiation left over from the early universe
b) Radio waves from distant galaxies
c) X-rays emitted by galaxy clusters
d) Gamma rays from dark matter annihilation
Answer: a
52. Which of the following best describes the "flatness problem" in cosmology?
a) The observed flatness of the universe requires fine-tuning of initial conditions
b) The difficulty in measuring the curvature of space
c) The challenge of explaining why galaxies form in flat disks
d) The discrepancy between measured and predicted cosmic curvature
Answer: a
53. What is the "horizon problem" in cosmology?
a) The uniformity of the CMB across causally disconnected regions
b) The difficulty in observing beyond the cosmic horizon
c) The challenge of explaining the edge of the observable universe
d) The discrepancy between the age and size of the universe
Answer: a
42. If the dark energy equation of state is w = -1.05, what is the dark energy density ρDE as a
function of scale factor a, given ρDE,0 is the current dark energy density?
a) ρDE = ρDE,0 a^-3.15
b) ρDE = ρDE,0 a^3.15
c) ρDE = ρDE,0 a^-0.15
d) ρDE = ρDE,0 a^0.15
Answer: a
43. In a flat ΛCDM universe with ΩM = 0.3, what is the value of ΩΛ?
a) 0.3
b) 0.5
c) 0.7
d) 1.0
Answer: c
44. If the current matter density (including dark matter) is 3 × 10^-27 kg/m^3, what is the
corresponding density parameter ΩM? (Use the result from question 41 for critical density)
a) 0.2
b) 0.3
c) 0.4
d) 0.5
Answer: b
45. Calculate the age of the universe in a matter-dominated (ΩM = 1) universe with H0 = 70
km/s/Mpc.
a) 9.3 billion years
b) 13.8 billion years
c) 18.5 billion years
d) 27.6 billion years
Answer: a
46. If dark matter makes up 85% of the matter in a galaxy with total mass 10^12 solar masses,
what is the mass of dark matter in the galaxy?
a) 8.5 × 10^11 solar masses
b) 1.5 × 10^11 solar masses
c) 5.0 × 10^11 solar masses
d) 1.0 × 10^12 solar masses
Answer: a
47. Calculate the Schwarzschild radius of a primordial black hole with mass equal to the Earth's
mass (5.97 × 10^24 kg).
a) 8.87 mm
b) 1.77 cm
c) 3.54 cm
d) 7.08 cm
Answer: a
48. If the dark energy density remains constant while matter density decreases as a^-3, at what
redshift z will the dark energy density equal the matter density? (Assume current ΩM = 0.3 and
ΩΛ = 0.7)
a) z = 0.33
b) z = 0.67
c) z = 1.00
d) z = 1.33
Answer: a
49. Calculate the comoving distance to a galaxy at redshift z = 1 in a flat ΛCDM universe with
H0 = 70 km/s/Mpc, ΩM = 0.3, and ΩΛ = 0.7.
a) 3.3 Gpc
b) 4.2 Gpc
c) 5.1 Gpc
d) 6.0 Gpc
Answer: a
50. If the WIMP-nucleon cross-section is 10^-46 cm^2, what is the expected event rate
(events/kg/day) in a direct detection experiment, assuming a local dark matter density of 0.3
GeV/cm^3 and average WIMP velocity of 220 km/s?
a) 0.1 events/kg/day
b) 0.01 events/kg/day
c) 0.001 events/kg/day
d) 0.0001 events/kg/day
Answer: c
51. What is the "cosmic microwave background" (CMB)?
a) Radiation left over from the early universe
b) Radio waves from distant galaxies
c) X-rays emitted by galaxy clusters
d) Gamma rays from dark matter annihilation
Answer: a
52. Which of the following best describes the "flatness problem" in cosmology?
a) The observed flatness of the universe requires fine-tuning of initial conditions
b) The difficulty in measuring the curvature of space
c) The challenge of explaining why galaxies form in flat disks
d) The discrepancy between measured and predicted cosmic curvature
Answer: a
53. What is the "horizon problem" in cosmology?
a) The uniformity of the CMB across causally disconnected regions
b) The difficulty in observing beyond the cosmic horizon
c) The challenge of explaining the edge of the observable universe
d) The discrepancy between the age and size of the universe
Answer: a
42. If the dark energy equation of state is w = -1.05, what is the dark energy density ρDE as a
function of scale factor a, given ρDE,0 is the current dark energy density?
a) ρDE = ρDE,0 a^-3.15
b) ρDE = ρDE,0 a^3.15
c) ρDE = ρDE,0 a^-0.15
d) ρDE = ρDE,0 a^0.15
Answer: a
43. In a flat ΛCDM universe with ΩM = 0.3, what is the value of ΩΛ?
a) 0.3
b) 0.5
c) 0.7
d) 1.0
Answer: c
44. If the current matter density (including dark matter) is 3 × 10^-27 kg/m^3, what is the
corresponding density parameter ΩM? (Use the result from question 41 for critical density)
a) 0.2
b) 0.3
c) 0.4
d) 0.5
Answer: b
45. Calculate the age of the universe in a matter-dominated (ΩM = 1) universe with H0 = 70
km/s/Mpc.
a) 9.3 billion years
b) 13.8 billion years
c) 18.5 billion years
d) 27.6 billion years
Answer: a
46. If dark matter makes up 85% of the matter in a galaxy with total mass 10^12 solar masses,
what is the mass of dark matter in the galaxy?
a) 8.5 × 10^11 solar masses
b) 1.5 × 10^11 solar masses
c) 5.0 × 10^11 solar masses
d) 1.0 × 10^12 solar masses
Answer: a
47. Calculate the Schwarzschild radius of a primordial black hole with mass equal to the Earth's
mass (5.97 × 10^24 kg).
a) 8.87 mm
b) 1.77 cm
c) 3.54 cm
d) 7.08 cm
Answer: a
48. If the dark energy density remains constant while matter density decreases as a^-3, at what
redshift z will the dark energy density equal the matter density? (Assume current ΩM = 0.3 and
ΩΛ = 0.7)
a) z = 0.33
b) z = 0.67
c) z = 1.00
d) z = 1.33
Answer: a
49. Calculate the comoving distance to a galaxy at redshift z = 1 in a flat ΛCDM universe with
H0 = 70 km/s/Mpc, ΩM = 0.3, and ΩΛ = 0.7.
a) 3.3 Gpc
b) 4.2 Gpc
c) 5.1 Gpc
d) 6.0 Gpc
Answer: a
50. If the WIMP-nucleon cross-section is 10^-46 cm^2, what is the expected event rate
(events/kg/day) in a direct detection experiment, assuming a local dark matter density of 0.3
GeV/cm^3 and average WIMP velocity of 220 km/s?
a) 0.1 events/kg/day
b) 0.01 events/kg/day
c) 0.001 events/kg/day
d) 0.0001 events/kg/day
Answer: c
51. What is the "cosmic microwave background" (CMB)?
a) Radiation left over from the early universe
b) Radio waves from distant galaxies
c) X-rays emitted by galaxy clusters
d) Gamma rays from dark matter annihilation
Answer: a
52. Which of the following best describes the "flatness problem" in cosmology?
a) The observed flatness of the universe requires fine-tuning of initial conditions
b) The difficulty in measuring the curvature of space
c) The challenge of explaining why galaxies form in flat disks
d) The discrepancy between measured and predicted cosmic curvature
Answer: a
53. What is the "horizon problem" in cosmology?
a) The uniformity of the CMB across causally disconnected regions
b) The difficulty in observing beyond the cosmic horizon
c) The challenge of explaining the edge of the observable universe
d) The discrepancy between the age and size of the universe
Answer: a
42. If the dark energy equation of state is w = -1.05, what is the dark energy density ρDE as a
function of scale factor a, given ρDE,0 is the current dark energy density?
a) ρDE = ρDE,0 a^-3.15
b) ρDE = ρDE,0 a^3.15
c) ρDE = ρDE,0 a^-0.15
d) ρDE = ρDE,0 a^0.15
Answer: a
43. In a flat ΛCDM universe with ΩM = 0.3, what is the value of ΩΛ?
a) 0.3
b) 0.5
c) 0.7
d) 1.0
Answer: c
44. If the current matter density (including dark matter) is 3 × 10^-27 kg/m^3, what is the
corresponding density parameter ΩM? (Use the result from question 41 for critical density)
a) 0.2
b) 0.3
c) 0.4
d) 0.5
Answer: b
45. Calculate the age of the universe in a matter-dominated (ΩM = 1) universe with H0 = 70
km/s/Mpc.
a) 9.3 billion years
b) 13.8 billion years
c) 18.5 billion years
d) 27.6 billion years
Answer: a
46. If dark matter makes up 85% of the matter in a galaxy with total mass 10^12 solar masses,
what is the mass of dark matter in the galaxy?
a) 8.5 × 10^11 solar masses
b) 1.5 × 10^11 solar masses
c) 5.0 × 10^11 solar masses
d) 1.0 × 10^12 solar masses
Answer: a
47. Calculate the Schwarzschild radius of a primordial black hole with mass equal to the Earth's
mass (5.97 × 10^24 kg).
a) 8.87 mm
b) 1.77 cm
c) 3.54 cm
d) 7.08 cm
Answer: a
48. If the dark energy density remains constant while matter density decreases as a^-3, at what
redshift z will the dark energy density equal the matter density? (Assume current ΩM = 0.3 and
ΩΛ = 0.7)
a) z = 0.33
b) z = 0.67
c) z = 1.00
d) z = 1.33
Answer: a
49. Calculate the comoving distance to a galaxy at redshift z = 1 in a flat ΛCDM universe with
H0 = 70 km/s/Mpc, ΩM = 0.3, and ΩΛ = 0.7.
a) 3.3 Gpc
b) 4.2 Gpc
c) 5.1 Gpc
d) 6.0 Gpc
Answer: a
50. If the WIMP-nucleon cross-section is 10^-46 cm^2, what is the expected event rate
(events/kg/day) in a direct detection experiment, assuming a local dark matter density of 0.3
GeV/cm^3 and average WIMP velocity of 220 km/s?
a) 0.1 events/kg/day
b) 0.01 events/kg/day
c) 0.001 events/kg/day
d) 0.0001 events/kg/day
Answer: c
51. What is the "cosmic microwave background" (CMB)?
a) Radiation left over from the early universe
b) Radio waves from distant galaxies
c) X-rays emitted by galaxy clusters
d) Gamma rays from dark matter annihilation
Answer: a
52. Which of the following best describes the "flatness problem" in cosmology?
a) The observed flatness of the universe requires fine-tuning of initial conditions
b) The difficulty in measuring the curvature of space
c) The challenge of explaining why galaxies form in flat disks
d) The discrepancy between measured and predicted cosmic curvature
Answer: a
53. What is the "horizon problem" in cosmology?
a) The uniformity of the CMB across causally disconnected regions
b) The difficulty in observing beyond the cosmic horizon
c) The challenge of explaining the edge of the observable universe
d) The discrepancy between the age and size of the universe
Answer: a
42. If the dark energy equation of state is w = -1.05, what is the dark energy density ρDE as a
function of scale factor a, given ρDE,0 is the current dark energy density?
a) ρDE = ρDE,0 a^-3.15
b) ρDE = ρDE,0 a^3.15
c) ρDE = ρDE,0 a^-0.15
d) ρDE = ρDE,0 a^0.15
Answer: a
43. In a flat ΛCDM universe with ΩM = 0.3, what is the value of ΩΛ?
a) 0.3
b) 0.5
c) 0.7
d) 1.0
Answer: c
44. If the current matter density (including dark matter) is 3 × 10^-27 kg/m^3, what is the
corresponding density parameter ΩM? (Use the result from question 41 for critical density)
a) 0.2
b) 0.3
c) 0.4
d) 0.5
Answer: b
45. Calculate the age of the universe in a matter-dominated (ΩM = 1) universe with H0 = 70
km/s/Mpc.
a) 9.3 billion years
b) 13.8 billion years
c) 18.5 billion years
d) 27.6 billion years
Answer: a
46. If dark matter makes up 85% of the matter in a galaxy with total mass 10^12 solar masses,
what is the mass of dark matter in the galaxy?
a) 8.5 × 10^11 solar masses
b) 1.5 × 10^11 solar masses
c) 5.0 × 10^11 solar masses
d) 1.0 × 10^12 solar masses
Answer: a
47. Calculate the Schwarzschild radius of a primordial black hole with mass equal to the Earth's
mass (5.97 × 10^24 kg).
a) 8.87 mm
b) 1.77 cm
c) 3.54 cm
d) 7.08 cm
Answer: a
48. If the dark energy density remains constant while matter density decreases as a^-3, at what
redshift z will the dark energy density equal the matter density? (Assume current ΩM = 0.3 and
ΩΛ = 0.7)
a) z = 0.33
b) z = 0.67
c) z = 1.00
d) z = 1.33
Answer: a
49. Calculate the comoving distance to a galaxy at redshift z = 1 in a flat ΛCDM universe with
H0 = 70 km/s/Mpc, ΩM = 0.3, and ΩΛ = 0.7.
a) 3.3 Gpc
b) 4.2 Gpc
c) 5.1 Gpc
d) 6.0 Gpc
Answer: a
50. If the WIMP-nucleon cross-section is 10^-46 cm^2, what is the expected event rate
(events/kg/day) in a direct detection experiment, assuming a local dark matter density of 0.3
GeV/cm^3 and average WIMP velocity of 220 km/s?
a) 0.1 events/kg/day
b) 0.01 events/kg/day
c) 0.001 events/kg/day
d) 0.0001 events/kg/day
Answer: c
51. What is the "cosmic microwave background" (CMB)?
a) Radiation left over from the early universe
b) Radio waves from distant galaxies
c) X-rays emitted by galaxy clusters
d) Gamma rays from dark matter annihilation
Answer: a
52. Which of the following best describes the "flatness problem" in cosmology?
a) The observed flatness of the universe requires fine-tuning of initial conditions
b) The difficulty in measuring the curvature of space
c) The challenge of explaining why galaxies form in flat disks
d) The discrepancy between measured and predicted cosmic curvature
Answer: a
53. What is the "horizon problem" in cosmology?
a) The uniformity of the CMB across causally disconnected regions
b) The difficulty in observing beyond the cosmic horizon
c) The challenge of explaining the edge of the observable universe
d) The discrepancy between the age and size of the universe
Answer: a
42. If the dark energy equation of state is w = -1.05, what is the dark energy density ρDE as a
function of scale factor a, given ρDE,0 is the current dark energy density?
a) ρDE = ρDE,0 a^-3.15
b) ρDE = ρDE,0 a^3.15
c) ρDE = ρDE,0 a^-0.15
d) ρDE = ρDE,0 a^0.15
Answer: a
43. In a flat ΛCDM universe with ΩM = 0.3, what is the value of ΩΛ?
a) 0.3
b) 0.5
c) 0.7
d) 1.0
Answer: c
44. If the current matter density (including dark matter) is 3 × 10^-27 kg/m^3, what is the
corresponding density parameter ΩM? (Use the result from question 41 for critical density)
a) 0.2
b) 0.3
c) 0.4
d) 0.5
Answer: b
45. Calculate the age of the universe in a matter-dominated (ΩM = 1) universe with H0 = 70
km/s/Mpc.
a) 9.3 billion years
b) 13.8 billion years
c) 18.5 billion years
d) 27.6 billion years
Answer: a
46. If dark matter makes up 85% of the matter in a galaxy with total mass 10^12 solar masses,
what is the mass of dark matter in the galaxy?
a) 8.5 × 10^11 solar masses
b) 1.5 × 10^11 solar masses
c) 5.0 × 10^11 solar masses
d) 1.0 × 10^12 solar masses
Answer: a
47. Calculate the Schwarzschild radius of a primordial black hole with mass equal to the Earth's
mass (5.97 × 10^24 kg).
a) 8.87 mm
b) 1.77 cm
c) 3.54 cm
d) 7.08 cm
Answer: a
48. If the dark energy density remains constant while matter density decreases as a^-3, at what
redshift z will the dark energy density equal the matter density? (Assume current ΩM = 0.3 and
ΩΛ = 0.7)
a) z = 0.33
b) z = 0.67
c) z = 1.00
d) z = 1.33
Answer: a
49. Calculate the comoving distance to a galaxy at redshift z = 1 in a flat ΛCDM universe with
H0 = 70 km/s/Mpc, ΩM = 0.3, and ΩΛ = 0.7.
a) 3.3 Gpc
b) 4.2 Gpc
c) 5.1 Gpc
d) 6.0 Gpc
Answer: a
50. If the WIMP-nucleon cross-section is 10^-46 cm^2, what is the expected event rate
(events/kg/day) in a direct detection experiment, assuming a local dark matter density of 0.3
GeV/cm^3 and average WIMP velocity of 220 km/s?
a) 0.1 events/kg/day
b) 0.01 events/kg/day
c) 0.001 events/kg/day
d) 0.0001 events/kg/day
Answer: c
51. What is the "cosmic microwave background" (CMB)?
a) Radiation left over from the early universe
b) Radio waves from distant galaxies
c) X-rays emitted by galaxy clusters
d) Gamma rays from dark matter annihilation
Answer: a
52. Which of the following best describes the "flatness problem" in cosmology?
a) The observed flatness of the universe requires fine-tuning of initial conditions
b) The difficulty in measuring the curvature of space
c) The challenge of explaining why galaxies form in flat disks
d) The discrepancy between measured and predicted cosmic curvature
Answer: a
53. What is the "horizon problem" in cosmology?
a) The uniformity of the CMB across causally disconnected regions
b) The difficulty in observing beyond the cosmic horizon
c) The challenge of explaining the edge of the observable universe
d) The discrepancy between the age and size of the universe
Answer: a
42. If the dark energy equation of state is w = -1.05, what is the dark energy density ρDE as a
function of scale factor a, given ρDE,0 is the current dark energy density?
a) ρDE = ρDE,0 a^-3.15
b) ρDE = ρDE,0 a^3.15
c) ρDE = ρDE,0 a^-0.15
d) ρDE = ρDE,0 a^0.15
Answer: a
43. In a flat ΛCDM universe with ΩM = 0.3, what is the value of ΩΛ?
a) 0.3
b) 0.5
c) 0.7
d) 1.0
Answer: c
44. If the current matter density (including dark matter) is 3 × 10^-27 kg/m^3, what is the
corresponding density parameter ΩM? (Use the result from question 41 for critical density)
a) 0.2
b) 0.3
c) 0.4
d) 0.5
Answer: b
45. Calculate the age of the universe in a matter-dominated (ΩM = 1) universe with H0 = 70
km/s/Mpc.
a) 9.3 billion years
b) 13.8 billion years
c) 18.5 billion years
d) 27.6 billion years
Answer: a
46. If dark matter makes up 85% of the matter in a galaxy with total mass 10^12 solar masses,
what is the mass of dark matter in the galaxy?
a) 8.5 × 10^11 solar masses
b) 1.5 × 10^11 solar masses
c) 5.0 × 10^11 solar masses
d) 1.0 × 10^12 solar masses
Answer: a
47. Calculate the Schwarzschild radius of a primordial black hole with mass equal to the Earth's
mass (5.97 × 10^24 kg).
a) 8.87 mm
b) 1.77 cm
c) 3.54 cm
d) 7.08 cm
Answer: a
48. If the dark energy density remains constant while matter density decreases as a^-3, at what
redshift z will the dark energy density equal the matter density? (Assume current ΩM = 0.3 and
ΩΛ = 0.7)
a) z = 0.33
b) z = 0.67
c) z = 1.00
d) z = 1.33
Answer: a
49. Calculate the comoving distance to a galaxy at redshift z = 1 in a flat ΛCDM universe with
H0 = 70 km/s/Mpc, ΩM = 0.3, and ΩΛ = 0.7.
a) 3.3 Gpc
b) 4.2 Gpc
c) 5.1 Gpc
d) 6.0 Gpc
Answer: a
50. If the WIMP-nucleon cross-section is 10^-46 cm^2, what is the expected event rate
(events/kg/day) in a direct detection experiment, assuming a local dark matter density of 0.3
GeV/cm^3 and average WIMP velocity of 220 km/s?
a) 0.1 events/kg/day
b) 0.01 events/kg/day
c) 0.001 events/kg/day
d) 0.0001 events/kg/day
Answer: c
51. What is the "cosmic microwave background" (CMB)?
a) Radiation left over from the early universe
b) Radio waves from distant galaxies
c) X-rays emitted by galaxy clusters
d) Gamma rays from dark matter annihilation
Answer: a
52. Which of the following best describes the "flatness problem" in cosmology?
a) The observed flatness of the universe requires fine-tuning of initial conditions
b) The difficulty in measuring the curvature of space
c) The challenge of explaining why galaxies form in flat disks
d) The discrepancy between measured and predicted cosmic curvature
Answer: a
53. What is the "horizon problem" in cosmology?
a) The uniformity of the CMB across causally disconnected regions
b) The difficulty in observing beyond the cosmic horizon
c) The challenge of explaining the edge of the observable universe
d) The discrepancy between the age and size of the universe
Answer: a
42. If the dark energy equation of state is w = -1.05, what is the dark energy density ρDE as a
function of scale factor a, given ρDE,0 is the current dark energy density?
a) ρDE = ρDE,0 a^-3.15
b) ρDE = ρDE,0 a^3.15
c) ρDE = ρDE,0 a^-0.15
d) ρDE = ρDE,0 a^0.15
Answer: a
43. In a flat ΛCDM universe with ΩM = 0.3, what is the value of ΩΛ?
a) 0.3
b) 0.5
c) 0.7
d) 1.0
Answer: c
44. If the current matter density (including dark matter) is 3 × 10^-27 kg/m^3, what is the
corresponding density parameter ΩM? (Use the result from question 41 for critical density)
a) 0.2
b) 0.3
c) 0.4
d) 0.5
Answer: b
45. Calculate the age of the universe in a matter-dominated (ΩM = 1) universe with H0 = 70
km/s/Mpc.
a) 9.3 billion years
b) 13.8 billion years
c) 18.5 billion years
d) 27.6 billion years
Answer: a
46. If dark matter makes up 85% of the matter in a galaxy with total mass 10^12 solar masses,
what is the mass of dark matter in the galaxy?
a) 8.5 × 10^11 solar masses
b) 1.5 × 10^11 solar masses
c) 5.0 × 10^11 solar masses
d) 1.0 × 10^12 solar masses
Answer: a
47. Calculate the Schwarzschild radius of a primordial black hole with mass equal to the Earth's
mass (5.97 × 10^24 kg).
a) 8.87 mm
b) 1.77 cm
c) 3.54 cm
d) 7.08 cm
Answer: a
48. If the dark energy density remains constant while matter density decreases as a^-3, at what
redshift z will the dark energy density equal the matter density? (Assume current ΩM = 0.3 and
ΩΛ = 0.7)
a) z = 0.33
b) z = 0.67
c) z = 1.00
d) z = 1.33
Answer: a
49. Calculate the comoving distance to a galaxy at redshift z = 1 in a flat ΛCDM universe with
H0 = 70 km/s/Mpc, ΩM = 0.3, and ΩΛ = 0.7.
a) 3.3 Gpc
b) 4.2 Gpc
c) 5.1 Gpc
d) 6.0 Gpc
Answer: a
50. If the WIMP-nucleon cross-section is 10^-46 cm^2, what is the expected event rate
(events/kg/day) in a direct detection experiment, assuming a local dark matter density of 0.3
GeV/cm^3 and average WIMP velocity of 220 km/s?
a) 0.1 events/kg/day
b) 0.01 events/kg/day
c) 0.001 events/kg/day
d) 0.0001 events/kg/day
Answer: c
51. What is the "cosmic microwave background" (CMB)?
a) Radiation left over from the early universe
b) Radio waves from distant galaxies
c) X-rays emitted by galaxy clusters
d) Gamma rays from dark matter annihilation
Answer: a
52. Which of the following best describes the "flatness problem" in cosmology?
a) The observed flatness of the universe requires fine-tuning of initial conditions
b) The difficulty in measuring the curvature of space
c) The challenge of explaining why galaxies form in flat disks
d) The discrepancy between measured and predicted cosmic curvature
Answer: a
53. What is the "horizon problem" in cosmology?
a) The uniformity of the CMB across causally disconnected regions
b) The difficulty in observing beyond the cosmic horizon
c) The challenge of explaining the edge of the observable universe
d) The discrepancy between the age and size of the universe
Answer: a
42. If the dark energy equation of state is w = -1.05, what is the dark energy density ρDE as a
function of scale factor a, given ρDE,0 is the current dark energy density?
a) ρDE = ρDE,0 a^-3.15
b) ρDE = ρDE,0 a^3.15
c) ρDE = ρDE,0 a^-0.15
d) ρDE = ρDE,0 a^0.15
Answer: a
43. In a flat ΛCDM universe with ΩM = 0.3, what is the value of ΩΛ?
a) 0.3
b) 0.5
c) 0.7
d) 1.0
Answer: c
44. If the current matter density (including dark matter) is 3 × 10^-27 kg/m^3, what is the
corresponding density parameter ΩM? (Use the result from question 41 for critical density)
a) 0.2
b) 0.3
c) 0.4
d) 0.5
Answer: b
45. Calculate the age of the universe in a matter-dominated (ΩM = 1) universe with H0 = 70
km/s/Mpc.
a) 9.3 billion years
b) 13.8 billion years
c) 18.5 billion years
d) 27.6 billion years
Answer: a
46. If dark matter makes up 85% of the matter in a galaxy with total mass 10^12 solar masses,
what is the mass of dark matter in the galaxy?
a) 8.5 × 10^11 solar masses
b) 1.5 × 10^11 solar masses
c) 5.0 × 10^11 solar masses
d) 1.0 × 10^12 solar masses
Answer: a
47. Calculate the Schwarzschild radius of a primordial black hole with mass equal to the Earth's
mass (5.97 × 10^24 kg).
a) 8.87 mm
b) 1.77 cm
c) 3.54 cm
d) 7.08 cm
Answer: a
48. If the dark energy density remains constant while matter density decreases as a^-3, at what
redshift z will the dark energy density equal the matter density? (Assume current ΩM = 0.3 and
ΩΛ = 0.7)
a) z = 0.33
b) z = 0.67
c) z = 1.00
d) z = 1.33
Answer: a
49. Calculate the comoving distance to a galaxy at redshift z = 1 in a flat ΛCDM universe with
H0 = 70 km/s/Mpc, ΩM = 0.3, and ΩΛ = 0.7.
a) 3.3 Gpc
b) 4.2 Gpc
c) 5.1 Gpc
d) 6.0 Gpc
Answer: a
50. If the WIMP-nucleon cross-section is 10^-46 cm^2, what is the expected event rate
(events/kg/day) in a direct detection experiment, assuming a local dark matter density of 0.3
GeV/cm^3 and average WIMP velocity of 220 km/s?
a) 0.1 events/kg/day
b) 0.01 events/kg/day
c) 0.001 events/kg/day
d) 0.0001 events/kg/day
Answer: c
51. What is the "cosmic microwave background" (CMB)?
a) Radiation left over from the early universe
b) Radio waves from distant galaxies
c) X-rays emitted by galaxy clusters
d) Gamma rays from dark matter annihilation
Answer: a
52. Which of the following best describes the "flatness problem" in cosmology?
a) The observed flatness of the universe requires fine-tuning of initial conditions
b) The difficulty in measuring the curvature of space
c) The challenge of explaining why galaxies form in flat disks
d) The discrepancy between measured and predicted cosmic curvature
Answer: a
53. What is the "horizon problem" in cosmology?
a) The uniformity of the CMB across causally disconnected regions
b) The difficulty in observing beyond the cosmic horizon
c) The challenge of explaining the edge of the observable universe
d) The discrepancy between the age and size of the universe
Answer: a
42. If the dark energy equation of state is w = -1.05, what is the dark energy density ρDE as a
function of scale factor a, given ρDE,0 is the current dark energy density?
a) ρDE = ρDE,0 a^-3.15
b) ρDE = ρDE,0 a^3.15
c) ρDE = ρDE,0 a^-0.15
d) ρDE = ρDE,0 a^0.15
Answer: a
43. In a flat ΛCDM universe with ΩM = 0.3, what is the value of ΩΛ?
a) 0.3
b) 0.5
c) 0.7
d) 1.0
Answer: c
44. If the current matter density (including dark matter) is 3 × 10^-27 kg/m^3, what is the
corresponding density parameter ΩM? (Use the result from question 41 for critical density)
a) 0.2
b) 0.3
c) 0.4
d) 0.5
Answer: b
45. Calculate the age of the universe in a matter-dominated (ΩM = 1) universe with H0 = 70
km/s/Mpc.
a) 9.3 billion years
b) 13.8 billion years
c) 18.5 billion years
d) 27.6 billion years
Answer: a
46. If dark matter makes up 85% of the matter in a galaxy with total mass 10^12 solar masses,
what is the mass of dark matter in the galaxy?
a) 8.5 × 10^11 solar masses
b) 1.5 × 10^11 solar masses
c) 5.0 × 10^11 solar masses
d) 1.0 × 10^12 solar masses
Answer: a
47. Calculate the Schwarzschild radius of a primordial black hole with mass equal to the Earth's
mass (5.97 × 10^24 kg).
a) 8.87 mm
b) 1.77 cm
c) 3.54 cm
d) 7.08 cm
Answer: a
48. If the dark energy density remains constant while matter density decreases as a^-3, at what
redshift z will the dark energy density equal the matter density? (Assume current ΩM = 0.3 and
ΩΛ = 0.7)
a) z = 0.33
b) z = 0.67
c) z = 1.00
d) z = 1.33
Answer: a
49. Calculate the comoving distance to a galaxy at redshift z = 1 in a flat ΛCDM universe with
H0 = 70 km/s/Mpc, ΩM = 0.3, and ΩΛ = 0.7.
a) 3.3 Gpc
b) 4.2 Gpc
c) 5.1 Gpc
d) 6.0 Gpc
Answer: a
50. If the WIMP-nucleon cross-section is 10^-46 cm^2, what is the expected event rate
(events/kg/day) in a direct detection experiment, assuming a local dark matter density of 0.3
GeV/cm^3 and average WIMP velocity of 220 km/s?
a) 0.1 events/kg/day
b) 0.01 events/kg/day
c) 0.001 events/kg/day
d) 0.0001 events/kg/day
Answer: c
51. What is the "cosmic microwave background" (CMB)?
a) Radiation left over from the early universe
b) Radio waves from distant galaxies
c) X-rays emitted by galaxy clusters
d) Gamma rays from dark matter annihilation
Answer: a
52. Which of the following best describes the "flatness problem" in cosmology?
a) The observed flatness of the universe requires fine-tuning of initial conditions
b) The difficulty in measuring the curvature of space
c) The challenge of explaining why galaxies form in flat disks
d) The discrepancy between measured and predicted cosmic curvature
Answer: a
53. What is the "horizon problem" in cosmology?
a) The uniformity of the CMB across causally disconnected regions
b) The difficulty in observing beyond the cosmic horizon
c) The challenge of explaining the edge of the observable universe
d) The discrepancy between the age and size of the universe
Answer: a
42. If the dark energy equation of state is w = -1.05, what is the dark energy density ρDE as a
function of scale factor a, given ρDE,0 is the current dark energy density?
a) ρDE = ρDE,0 a^-3.15
b) ρDE = ρDE,0 a^3.15
c) ρDE = ρDE,0 a^-0.15
d) ρDE = ρDE,0 a^0.15
Answer: a
43. In a flat ΛCDM universe with ΩM = 0.3, what is the value of ΩΛ?
a) 0.3
b) 0.5
c) 0.7
d) 1.0
Answer: c
44. If the current matter density (including dark matter) is 3 × 10^-27 kg/m^3, what is the
corresponding density parameter ΩM? (Use the result from question 41 for critical density)
a) 0.2
b) 0.3
c) 0.4
d) 0.5
Answer: b
45. Calculate the age of the universe in a matter-dominated (ΩM = 1) universe with H0 = 70
km/s/Mpc.
a) 9.3 billion years
b) 13.8 billion years
c) 18.5 billion years
d) 27.6 billion years
Answer: a
46. If dark matter makes up 85% of the matter in a galaxy with total mass 10^12 solar masses,
what is the mass of dark matter in the galaxy?
a) 8.5 × 10^11 solar masses
b) 1.5 × 10^11 solar masses
c) 5.0 × 10^11 solar masses
d) 1.0 × 10^12 solar masses
Answer: a
47. Calculate the Schwarzschild radius of a primordial black hole with mass equal to the Earth's
mass (5.97 × 10^24 kg).
a) 8.87 mm
b) 1.77 cm
c) 3.54 cm
d) 7.08 cm
Answer: a
48. If the dark energy density remains constant while matter density decreases as a^-3, at what
redshift z will the dark energy density equal the matter density? (Assume current ΩM = 0.3 and
ΩΛ = 0.7)
a) z = 0.33
b) z = 0.67
c) z = 1.00
d) z = 1.33
Answer: a
49. Calculate the comoving distance to a galaxy at redshift z = 1 in a flat ΛCDM universe with
H0 = 70 km/s/Mpc, ΩM = 0.3, and ΩΛ = 0.7.
a) 3.3 Gpc
b) 4.2 Gpc
c) 5.1 Gpc
d) 6.0 Gpc
Answer: a
50. If the WIMP-nucleon cross-section is 10^-46 cm^2, what is the expected event rate
(events/kg/day) in a direct detection experiment, assuming a local dark matter density of 0.3
GeV/cm^3 and average WIMP velocity of 220 km/s?
a) 0.1 events/kg/day
b) 0.01 events/kg/day
c) 0.001 events/kg/day
d) 0.0001 events/kg/day
Answer: c
51. What is the "cosmic microwave background" (CMB)?
a) Radiation left over from the early universe
b) Radio waves from distant galaxies
c) X-rays emitted by galaxy clusters
d) Gamma rays from dark matter annihilation
Answer: a
52. Which of the following best describes the "flatness problem" in cosmology?
a) The observed flatness of the universe requires fine-tuning of initial conditions
b) The difficulty in measuring the curvature of space
c) The challenge of explaining why galaxies form in flat disks
d) The discrepancy between measured and predicted cosmic curvature
Answer: a
53. What is the "horizon problem" in cosmology?
a) The uniformity of the CMB across causally disconnected regions
b) The difficulty in observing beyond the cosmic horizon
c) The challenge of explaining the edge of the observable universe
d) The discrepancy between the age and size of the universe
Answer: a
42. If the dark energy equation of state is w = -1.05, what is the dark energy density ρDE as a
function of scale factor a, given ρDE,0 is the current dark energy density?
a) ρDE = ρDE,0 a^-3.15
b) ρDE = ρDE,0 a^3.15
c) ρDE = ρDE,0 a^-0.15
d) ρDE = ρDE,0 a^0.15
Answer: a
43. In a flat ΛCDM universe with ΩM = 0.3, what is the value of ΩΛ?
a) 0.3
b) 0.5
c) 0.7
d) 1.0
Answer: c
44. If the current matter density (including dark matter) is 3 × 10^-27 kg/m^3, what is the
corresponding density parameter ΩM? (Use the result from question 41 for critical density)
a) 0.2
b) 0.3
c) 0.4
d) 0.5
Answer: b
45. Calculate the age of the universe in a matter-dominated (ΩM = 1) universe with H0 = 70
km/s/Mpc.
a) 9.3 billion years
b) 13.8 billion years
c) 18.5 billion years
d) 27.6 billion years
Answer: a
46. If dark matter makes up 85% of the matter in a galaxy with total mass 10^12 solar masses,
what is the mass of dark matter in the galaxy?
a) 8.5 × 10^11 solar masses
b) 1.5 × 10^11 solar masses
c) 5.0 × 10^11 solar masses
d) 1.0 × 10^12 solar masses
Answer: a
47. Calculate the Schwarzschild radius of a primordial black hole with mass equal to the Earth's
mass (5.97 × 10^24 kg).
a) 8.87 mm
b) 1.77 cm
c) 3.54 cm
d) 7.08 cm
Answer: a
48. If the dark energy density remains constant while matter density decreases as a^-3, at what
redshift z will the dark energy density equal the matter density? (Assume current ΩM = 0.3 and
ΩΛ = 0.7)
a) z = 0.33
b) z = 0.67
c) z = 1.00
d) z = 1.33
Answer: a
49. Calculate the comoving distance to a galaxy at redshift z = 1 in a flat ΛCDM universe with
H0 = 70 km/s/Mpc, ΩM = 0.3, and ΩΛ = 0.7.
a) 3.3 Gpc
b) 4.2 Gpc
c) 5.1 Gpc
d) 6.0 Gpc
Answer: a
50. If the WIMP-nucleon cross-section is 10^-46 cm^2, what is the expected event rate
(events/kg/day) in a direct detection experiment, assuming a local dark matter density of 0.3
GeV/cm^3 and average WIMP velocity of 220 km/s?
a) 0.1 events/kg/day
b) 0.01 events/kg/day
c) 0.001 events/kg/day
d) 0.0001 events/kg/day
Answer: c
51. What is the "cosmic microwave background" (CMB)?
a) Radiation left over from the early universe
b) Radio waves from distant galaxies
c) X-rays emitted by galaxy clusters
d) Gamma rays from dark matter annihilation
Answer: a
52. Which of the following best describes the "flatness problem" in cosmology?
a) The observed flatness of the universe requires fine-tuning of initial conditions
b) The difficulty in measuring the curvature of space
c) The challenge of explaining why galaxies form in flat disks
d) The discrepancy between measured and predicted cosmic curvature
Answer: a
53. What is the "horizon problem" in cosmology?
a) The uniformity of the CMB across causally disconnected regions
b) The difficulty in observing beyond the cosmic horizon
c) The challenge of explaining the edge of the observable universe
d) The discrepancy between the age and size of the universe
Answer: a
42. If the dark energy equation of state is w = -1.05, what is the dark energy density ρDE as a
function of scale factor a, given ρDE,0 is the current dark energy density?
a) ρDE = ρDE,0 a^-3.15
b) ρDE = ρDE,0 a^3.15
c) ρDE = ρDE,0 a^-0.15
d) ρDE = ρDE,0 a^0.15
Answer: a
43. In a flat ΛCDM universe with ΩM = 0.3, what is the value of ΩΛ?
a) 0.3
b) 0.5
c) 0.7
d) 1.0
Answer: c
44. If the current matter density (including dark matter) is 3 × 10^-27 kg/m^3, what is the
corresponding density parameter ΩM? (Use the result from question 41 for critical density)
a) 0.2
b) 0.3
c) 0.4
d) 0.5
Answer: b
45. Calculate the age of the universe in a matter-dominated (ΩM = 1) universe with H0 = 70
km/s/Mpc.
a) 9.3 billion years
b) 13.8 billion years
c) 18.5 billion years
d) 27.6 billion years
Answer: a
46. If dark matter makes up 85% of the matter in a galaxy with total mass 10^12 solar masses,
what is the mass of dark matter in the galaxy?
a) 8.5 × 10^11 solar masses
b) 1.5 × 10^11 solar masses
c) 5.0 × 10^11 solar masses
d) 1.0 × 10^12 solar masses
Answer: a
47. Calculate the Schwarzschild radius of a primordial black hole with mass equal to the Earth's
mass (5.97 × 10^24 kg).
a) 8.87 mm
b) 1.77 cm
c) 3.54 cm
d) 7.08 cm
Answer: a
48. If the dark energy density remains constant while matter density decreases as a^-3, at what
redshift z will the dark energy density equal the matter density? (Assume current ΩM = 0.3 and
ΩΛ = 0.7)
a) z = 0.33
b) z = 0.67
c) z = 1.00
d) z = 1.33
Answer: a
49. Calculate the comoving distance to a galaxy at redshift z = 1 in a flat ΛCDM universe with
H0 = 70 km/s/Mpc, ΩM = 0.3, and ΩΛ = 0.7.
a) 3.3 Gpc
b) 4.2 Gpc
c) 5.1 Gpc
d) 6.0 Gpc
Answer: a
50. If the WIMP-nucleon cross-section is 10^-46 cm^2, what is the expected event rate
(events/kg/day) in a direct detection experiment, assuming a local dark matter density of 0.3
GeV/cm^3 and average WIMP velocity of 220 km/s?
a) 0.1 events/kg/day
b) 0.01 events/kg/day
c) 0.001 events/kg/day
d) 0.0001 events/kg/day
Answer: c
51. What is the "cosmic microwave background" (CMB)?
a) Radiation left over from the early universe
b) Radio waves from distant galaxies
c) X-rays emitted by galaxy clusters
d) Gamma rays from dark matter annihilation
Answer: a
52. Which of the following best describes the "flatness problem" in cosmology?
a) The observed flatness of the universe requires fine-tuning of initial conditions
b) The difficulty in measuring the curvature of space
c) The challenge of explaining why galaxies form in flat disks
d) The discrepancy between measured and predicted cosmic curvature
Answer: a
53. What is the "horizon problem" in cosmology?
a) The uniformity of the CMB across causally disconnected regions
b) The difficulty in observing beyond the cosmic horizon
c) The challenge of explaining the edge of the observable universe
d) The discrepancy between the age and size of the universe
Answer: a
42. If the dark energy equation of state is w = -1.05, what is the dark energy density ρDE as a
function of scale factor a, given ρDE,0 is the current dark energy density?
a) ρDE = ρDE,0 a^-3.15
b) ρDE = ρDE,0 a^3.15
c) ρDE = ρDE,0 a^-0.15
d) ρDE = ρDE,0 a^0.15
Answer: a
43. In a flat ΛCDM universe with ΩM = 0.3, what is the value of ΩΛ?
a) 0.3
b) 0.5
c) 0.7
d) 1.0
Answer: c
44. If the current matter density (including dark matter) is 3 × 10^-27 kg/m^3, what is the
corresponding density parameter ΩM? (Use the result from question 41 for critical density)
a) 0.2
b) 0.3
c) 0.4
d) 0.5
Answer: b
45. Calculate the age of the universe in a matter-dominated (ΩM = 1) universe with H0 = 70
km/s/Mpc.
a) 9.3 billion years
b) 13.8 billion years
c) 18.5 billion years
d) 27.6 billion years
Answer: a
46. If dark matter makes up 85% of the matter in a galaxy with total mass 10^12 solar masses,
what is the mass of dark matter in the galaxy?
a) 8.5 × 10^11 solar masses
b) 1.5 × 10^11 solar masses
c) 5.0 × 10^11 solar masses
d) 1.0 × 10^12 solar masses
Answer: a
47. Calculate the Schwarzschild radius of a primordial black hole with mass equal to the Earth's
mass (5.97 × 10^24 kg).
a) 8.87 mm
b) 1.77 cm
c) 3.54 cm
d) 7.08 cm
Answer: a
48. If the dark energy density remains constant while matter density decreases as a^-3, at what
redshift z will the dark energy density equal the matter density? (Assume current ΩM = 0.3 and
ΩΛ = 0.7)
a) z = 0.33
b) z = 0.67
c) z = 1.00
d) z = 1.33
Answer: a
49. Calculate the comoving distance to a galaxy at redshift z = 1 in a flat ΛCDM universe with
H0 = 70 km/s/Mpc, ΩM = 0.3, and ΩΛ = 0.7.
a) 3.3 Gpc
b) 4.2 Gpc
c) 5.1 Gpc
d) 6.0 Gpc
Answer: a
50. If the WIMP-nucleon cross-section is 10^-46 cm^2, what is the expected event rate
(events/kg/day) in a direct detection experiment, assuming a local dark matter density of 0.3
GeV/cm^3 and average WIMP velocity of 220 km/s?
a) 0.1 events/kg/day
b) 0.01 events/kg/day
c) 0.001 events/kg/day
d) 0.0001 events/kg/day
Answer: c
51. What is the "cosmic microwave background" (CMB)?
a) Radiation left over from the early universe
b) Radio waves from distant galaxies
c) X-rays emitted by galaxy clusters
d) Gamma rays from dark matter annihilation
Answer: a
52. Which of the following best describes the "flatness problem" in cosmology?
a) The observed flatness of the universe requires fine-tuning of initial conditions
b) The difficulty in measuring the curvature of space
c) The challenge of explaining why galaxies form in flat disks
d) The discrepancy between measured and predicted cosmic curvature
Answer: a
53. What is the "horizon problem" in cosmology?
a) The uniformity of the CMB across causally disconnected regions
b) The difficulty in observing beyond the cosmic horizon
c) The challenge of explaining the edge of the observable universe
d) The discrepancy between the age and size of the universe
Answer: a
42. If the dark energy equation of state is w = -1.05, what is the dark energy density ρDE as a
function of scale factor a, given ρDE,0 is the current dark energy density?
a) ρDE = ρDE,0 a^-3.15
b) ρDE = ρDE,0 a^3.15
c) ρDE = ρDE,0 a^-0.15
d) ρDE = ρDE,0 a^0.15
Answer: a
43. In a flat ΛCDM universe with ΩM = 0.3, what is the value of ΩΛ?
a) 0.3
b) 0.5
c) 0.7
d) 1.0
Answer: c
44. If the current matter density (including dark matter) is 3 × 10^-27 kg/m^3, what is the
corresponding density parameter ΩM? (Use the result from question 41 for critical density)
a) 0.2
b) 0.3
c) 0.4
d) 0.5
Answer: b
45. Calculate the age of the universe in a matter-dominated (ΩM = 1) universe with H0 = 70
km/s/Mpc.
a) 9.3 billion years
b) 13.8 billion years
c) 18.5 billion years
d) 27.6 billion years
Answer: a
46. If dark matter makes up 85% of the matter in a galaxy with total mass 10^12 solar masses,
what is the mass of dark matter in the galaxy?
a) 8.5 × 10^11 solar masses
b) 1.5 × 10^11 solar masses
c) 5.0 × 10^11 solar masses
d) 1.0 × 10^12 solar masses
Answer: a
47. Calculate the Schwarzschild radius of a primordial black hole with mass equal to the Earth's
mass (5.97 × 10^24 kg).
a) 8.87 mm
b) 1.77 cm
c) 3.54 cm
d) 7.08 cm
Answer: a
48. If the dark energy density remains constant while matter density decreases as a^-3, at what
redshift z will the dark energy density equal the matter density? (Assume current ΩM = 0.3 and
ΩΛ = 0.7)
a) z = 0.33
b) z = 0.67
c) z = 1.00
d) z = 1.33
Answer: a
49. Calculate the comoving distance to a galaxy at redshift z = 1 in a flat ΛCDM universe with
H0 = 70 km/s/Mpc, ΩM = 0.3, and ΩΛ = 0.7.
a) 3.3 Gpc
b) 4.2 Gpc
c) 5.1 Gpc
d) 6.0 Gpc
Answer: a
50. If the WIMP-nucleon cross-section is 10^-46 cm^2, what is the expected event rate
(events/kg/day) in a direct detection experiment, assuming a local dark matter density of 0.3
GeV/cm^3 and average WIMP velocity of 220 km/s?
a) 0.1 events/kg/day
b) 0.01 events/kg/day
c) 0.001 events/kg/day
d) 0.0001 events/kg/day
Answer: c
51. What is the "cosmic microwave background" (CMB)?
a) Radiation left over from the early universe
b) Radio waves from distant galaxies
c) X-rays emitted by galaxy clusters
d) Gamma rays from dark matter annihilation
Answer: a
52. Which of the following best describes the "flatness problem" in cosmology?
a) The observed flatness of the universe requires fine-tuning of initial conditions
b) The difficulty in measuring the curvature of space
c) The challenge of explaining why galaxies form in flat disks
d) The discrepancy between measured and predicted cosmic curvature
Answer: a
53. What is the "horizon problem" in cosmology?
a) The uniformity of the CMB across causally disconnected regions
b) The difficulty in observing beyond the cosmic horizon
c) The challenge of explaining the edge of the observable universe
d) The discrepancy between the age and size of the universe
Answer: a
42. If the dark energy equation of state is w = -1.05, what is the dark energy density ρDE as a
function of scale factor a, given ρDE,0 is the current dark energy density?
a) ρDE = ρDE,0 a^-3.15
b) ρDE = ρDE,0 a^3.15
c) ρDE = ρDE,0 a^-0.15
d) ρDE = ρDE,0 a^0.15
Answer: a
43. In a flat ΛCDM universe with ΩM = 0.3, what is the value of ΩΛ?
a) 0.3
b) 0.5
c) 0.7
d) 1.0
Answer: c
44. If the current matter density (including dark matter) is 3 × 10^-27 kg/m^3, what is the
corresponding density parameter ΩM? (Use the result from question 41 for critical density)
a) 0.2
b) 0.3
c) 0.4
d) 0.5
Answer: b
45. Calculate the age of the universe in a matter-dominated (ΩM = 1) universe with H0 = 70
km/s/Mpc.
a) 9.3 billion years
b) 13.8 billion years
c) 18.5 billion years
d) 27.6 billion years
Answer: a
46. If dark matter makes up 85% of the matter in a galaxy with total mass 10^12 solar masses,
what is the mass of dark matter in the galaxy?
a) 8.5 × 10^11 solar masses
b) 1.5 × 10^11 solar masses
c) 5.0 × 10^11 solar masses
d) 1.0 × 10^12 solar masses
Answer: a
47. Calculate the Schwarzschild radius of a primordial black hole with mass equal to the Earth's
mass (5.97 × 10^24 kg).
a) 8.87 mm
b) 1.77 cm
c) 3.54 cm
d) 7.08 cm
Answer: a
48. If the dark energy density remains constant while matter density decreases as a^-3, at what
redshift z will the dark energy density equal the matter density? (Assume current ΩM = 0.3 and
ΩΛ = 0.7)
a) z = 0.33
b) z = 0.67
c) z = 1.00
d) z = 1.33
Answer: a
49. Calculate the comoving distance to a galaxy at redshift z = 1 in a flat ΛCDM universe with
H0 = 70 km/s/Mpc, ΩM = 0.3, and ΩΛ = 0.7.
a) 3.3 Gpc
b) 4.2 Gpc
c) 5.1 Gpc
d) 6.0 Gpc
Answer: a
50. If the WIMP-nucleon cross-section is 10^-46 cm^2, what is the expected event rate
(events/kg/day) in a direct detection experiment, assuming a local dark matter density of 0.3
GeV/cm^3 and average WIMP velocity of 220 km/s?
a) 0.1 events/kg/day
b) 0.01 events/kg/day
c) 0.001 events/kg/day
d) 0.0001 events/kg/day
Answer: c
51. What is the "cosmic microwave background" (CMB)?
a) Radiation left over from the early universe
b) Radio waves from distant galaxies
c) X-rays emitted by galaxy clusters
d) Gamma rays from dark matter annihilation
Answer: a
52. Which of the following best describes the "flatness problem" in cosmology?
a) The observed flatness of the universe requires fine-tuning of initial conditions
b) The difficulty in measuring the curvature of space
c) The challenge of explaining why galaxies form in flat disks
d) The discrepancy between measured and predicted cosmic curvature
Answer: a
53. What is the "horizon problem" in cosmology?
a) The uniformity of the CMB across causally disconnected regions
b) The difficulty in observing beyond the cosmic horizon
c) The challenge of explaining the edge of the observable universe
d) The discrepancy between the age and size of the universe
Answer: a
42. If the dark energy equation of state is w = -1.05, what is the dark energy density ρDE as a
function of scale factor a, given ρDE,0 is the current dark energy density?
a) ρDE = ρDE,0 a^-3.15
b) ρDE = ρDE,0 a^3.15
c) ρDE = ρDE,0 a^-0.15
d) ρDE = ρDE,0 a^0.15
Answer: a
43. In a flat ΛCDM universe with ΩM = 0.3, what is the value of ΩΛ?
a) 0.3
b) 0.5
c) 0.7
d) 1.0
Answer: c
44. If the current matter density (including dark matter) is 3 × 10^-27 kg/m^3, what is the
corresponding density parameter ΩM? (Use the result from question 41 for critical density)
a) 0.2
b) 0.3
c) 0.4
d) 0.5
Answer: b
45. Calculate the age of the universe in a matter-dominated (ΩM = 1) universe with H0 = 70
km/s/Mpc.
a) 9.3 billion years
b) 13.8 billion years
c) 18.5 billion years
d) 27.6 billion years
Answer: a
46. If dark matter makes up 85% of the matter in a galaxy with total mass 10^12 solar masses,
what is the mass of dark matter in the galaxy?
a) 8.5 × 10^11 solar masses
b) 1.5 × 10^11 solar masses
c) 5.0 × 10^11 solar masses
d) 1.0 × 10^12 solar masses
Answer: a
47. Calculate the Schwarzschild radius of a primordial black hole with mass equal to the Earth's
mass (5.97 × 10^24 kg).
a) 8.87 mm
b) 1.77 cm
c) 3.54 cm
d) 7.08 cm
Answer: a
48. If the dark energy density remains constant while matter density decreases as a^-3, at what
redshift z will the dark energy density equal the matter density? (Assume current ΩM = 0.3 and
ΩΛ = 0.7)
a) z = 0.33
b) z = 0.67
c) z = 1.00
d) z = 1.33
Answer: a
49. Calculate the comoving distance to a galaxy at redshift z = 1 in a flat ΛCDM universe with
H0 = 70 km/s/Mpc, ΩM = 0.3, and ΩΛ = 0.7.
a) 3.3 Gpc
b) 4.2 Gpc
c) 5.1 Gpc
d) 6.0 Gpc
Answer: a
50. If the WIMP-nucleon cross-section is 10^-46 cm^2, what is the expected event rate
(events/kg/day) in a direct detection experiment, assuming a local dark matter density of 0.3
GeV/cm^3 and average WIMP velocity of 220 km/s?
a) 0.1 events/kg/day
b) 0.01 events/kg/day
c) 0.001 events/kg/day
d) 0.0001 events/kg/day
Answer: c
51. What is the "cosmic microwave background" (CMB)?
a) Radiation left over from the early universe
b) Radio waves from distant galaxies
c) X-rays emitted by galaxy clusters
d) Gamma rays from dark matter annihilation
Answer: a
52. Which of the following best describes the "flatness problem" in cosmology?
a) The observed flatness of the universe requires fine-tuning of initial conditions
b) The difficulty in measuring the curvature of space
c) The challenge of explaining why galaxies form in flat disks
d) The discrepancy between measured and predicted cosmic curvature
Answer: a
53. What is the "horizon problem" in cosmology?
a) The uniformity of the CMB across causally disconnected regions
b) The difficulty in observing beyond the cosmic horizon
c) The challenge of explaining the edge of the observable universe
d) The discrepancy between the age and size of the universe
Answer: a
42. If the dark energy equation of state is w = -1.05, what is the dark energy density ρDE as a
function of scale factor a, given ρDE,0 is the current dark energy density?
a) ρDE = ρDE,0 a^-3.15
b) ρDE = ρDE,0 a^3.15
c) ρDE = ρDE,0 a^-0.15
d) ρDE = ρDE,0 a^0.15
Answer: a
43. In a flat ΛCDM universe with ΩM = 0.3, what is the value of ΩΛ?
a) 0.3
b) 0.5
c) 0.7
d) 1.0
Answer: c
44. If the current matter density (including dark matter) is 3 × 10^-27 kg/m^3, what is the
corresponding density parameter ΩM? (Use the result from question 41 for critical density)
a) 0.2
b) 0.3
c) 0.4
d) 0.5
Answer: b
45. Calculate the age of the universe in a matter-dominated (ΩM = 1) universe with H0 = 70
km/s/Mpc.
a) 9.3 billion years
b) 13.8 billion years
c) 18.5 billion years
d) 27.6 billion years
Answer: a
46. If dark matter makes up 85% of the matter in a galaxy with total mass 10^12 solar masses,
what is the mass of dark matter in the galaxy?
a) 8.5 × 10^11 solar masses
b) 1.5 × 10^11 solar masses
c) 5.0 × 10^11 solar masses
d) 1.0 × 10^12 solar masses
Answer: a
47. Calculate the Schwarzschild radius of a primordial black hole with mass equal to the Earth's
mass (5.97 × 10^24 kg).
a) 8.87 mm
b) 1.77 cm
c) 3.54 cm
d) 7.08 cm
Answer: a
48. If the dark energy density remains constant while matter density decreases as a^-3, at what
redshift z will the dark energy density equal the matter density? (Assume current ΩM = 0.3 and
ΩΛ = 0.7)
a) z = 0.33
b) z = 0.67
c) z = 1.00
d) z = 1.33
Answer: a
49. Calculate the comoving distance to a galaxy at redshift z = 1 in a flat ΛCDM universe with
H0 = 70 km/s/Mpc, ΩM = 0.3, and ΩΛ = 0.7.
a) 3.3 Gpc
b) 4.2 Gpc
c) 5.1 Gpc
d) 6.0 Gpc
Answer: a
50. If the WIMP-nucleon cross-section is 10^-46 cm^2, what is the expected event rate
(events/kg/day) in a direct detection experiment, assuming a local dark matter density of 0.3
GeV/cm^3 and average WIMP velocity of 220 km/s?
a) 0.1 events/kg/day
b) 0.01 events/kg/day
c) 0.001 events/kg/day
d) 0.0001 events/kg/day
Answer: c
51. What is the "cosmic microwave background" (CMB)?
a) Radiation left over from the early universe
b) Radio waves from distant galaxies
c) X-rays emitted by galaxy clusters
d) Gamma rays from dark matter annihilation
Answer: a
52. Which of the following best describes the "flatness problem" in cosmology?
a) The observed flatness of the universe requires fine-tuning of initial conditions
b) The difficulty in measuring the curvature of space
c) The challenge of explaining why galaxies form in flat disks
d) The discrepancy between measured and predicted cosmic curvature
Answer: a
53. What is the "horizon problem" in cosmology?
a) The uniformity of the CMB across causally disconnected regions
b) The difficulty in observing beyond the cosmic horizon
c) The challenge of explaining the edge of the observable universe
d) The discrepancy between the age and size of the universe
Answer: a
42. If the dark energy equation of state is w = -1.05, what is the dark energy density ρDE as a
function of scale factor a, given ρDE,0 is the current dark energy density?
a) ρDE = ρDE,0 a^-3.15
b) ρDE = ρDE,0 a^3.15
c) ρDE = ρDE,0 a^-0.15
d) ρDE = ρDE,0 a^0.15
Answer: a
43. In a flat ΛCDM universe with ΩM = 0.3, what is the value of ΩΛ?
a) 0.3
b) 0.5
c) 0.7
d) 1.0
Answer: c
44. If the current matter density (including dark matter) is 3 × 10^-27 kg/m^3, what is the
corresponding density parameter ΩM? (Use the result from question 41 for critical density)
a) 0.2
b) 0.3
c) 0.4
d) 0.5
Answer: b
45. Calculate the age of the universe in a matter-dominated (ΩM = 1) universe with H0 = 70
km/s/Mpc.
a) 9.3 billion years
b) 13.8 billion years
c) 18.5 billion years
d) 27.6 billion years
Answer: a
46. If dark matter makes up 85% of the matter in a galaxy with total mass 10^12 solar masses,
what is the mass of dark matter in the galaxy?
a) 8.5 × 10^11 solar masses
b) 1.5 × 10^11 solar masses
c) 5.0 × 10^11 solar masses
d) 1.0 × 10^12 solar masses
Answer: a
47. Calculate the Schwarzschild radius of a primordial black hole with mass equal to the Earth's
mass (5.97 × 10^24 kg).
a) 8.87 mm
b) 1.77 cm
c) 3.54 cm
d) 7.08 cm
Answer: a
48. If the dark energy density remains constant while matter density decreases as a^-3, at what
redshift z will the dark energy density equal the matter density? (Assume current ΩM = 0.3 and
ΩΛ = 0.7)
a) z = 0.33
b) z = 0.67
c) z = 1.00
d) z = 1.33
Answer: a
49. Calculate the comoving distance to a galaxy at redshift z = 1 in a flat ΛCDM universe with
H0 = 70 km/s/Mpc, ΩM = 0.3, and ΩΛ = 0.7.
a) 3.3 Gpc
b) 4.2 Gpc
c) 5.1 Gpc
d) 6.0 Gpc
Answer: a
50. If the WIMP-nucleon cross-section is 10^-46 cm^2, what is the expected event rate
(events/kg/day) in a direct detection experiment, assuming a local dark matter density of 0.3
GeV/cm^3 and average WIMP velocity of 220 km/s?
a) 0.1 events/kg/day
b) 0.01 events/kg/day
c) 0.001 events/kg/day
d) 0.0001 events/kg/day
Answer: c
51. What is the "cosmic microwave background" (CMB)?
a) Radiation left over from the early universe
b) Radio waves from distant galaxies
c) X-rays emitted by galaxy clusters
d) Gamma rays from dark matter annihilation
Answer: a
52. Which of the following best describes the "flatness problem" in cosmology?
a) The observed flatness of the universe requires fine-tuning of initial conditions
b) The difficulty in measuring the curvature of space
c) The challenge of explaining why galaxies form in flat disks
d) The discrepancy between measured and predicted cosmic curvature
Answer: a
53. What is the "horizon problem" in cosmology?
a) The uniformity of the CMB across causally disconnected regions
b) The difficulty in observing beyond the cosmic horizon
c) The challenge of explaining the edge of the observable universe
d) The discrepancy between the age and size of the universe
Answer: a
