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D.5 – Further cosmology (HL only)
Description
Nature of science:
Cognitive bias: According to everybody’s expectations the rate of expansion of the universe should be slowing down because of gravity. The detailed results from the 1998 (and subsequent) observations on distant supernovae showed that the opposite was in fact true. The accelerated expansion of the universe, whereas experimentally verified, is still an unexplained phenomenon. (3.5)
Understandings:
- The cosmological principle
- Rotation curves and the mass of galaxies
- Dark matter
- Fluctuations in the CMB
- The cosmological origin of redshift
- Critical density
- Dark energy
Applications and skills:
- Describing the cosmological principle and its role in models of the universe
- Describing rotation curves as evidence for dark matter
- Deriving rotational velocity from Newtonian gravitation
- Describing and interpreting the observed anisotropies in the CMB
- Deriving critical density from Newtonian gravitation
- Sketching and interpreting graphs showing the variation of the cosmic scale factor with time
- Describing qualitatively the cosmic scale factor in models with and without dark energy
Guidance:
- Students are expected to be able to refer to rotation curves as evidence for dark matter and must be aware of types of candidates for dark matter
- Students must be familiar with the main results of COBE, WMAP and the Planck space observatory
- Students are expected to demonstrate that the temperature of the universe varies with the cosmic scale factor as
Data booklet reference:
International-mindedness:
- This is a highly collaborative field of research involving scientists from all over the world
Theory of knowledge:
- Experimental facts show that the expansion of the universe is accelerating yet no one understands why. Is this an example of something that we will never know?
Aims:
- Aim 2: unlike how it was just a few decades ago, the field of cosmology has now developed so much that cosmology has become a very exact science on the same level as the rest of physics
- Aim 10: it is quite extraordinary that to settle the issue of the fate of the universe, cosmology, the physics of the very large, required the help of particle physics, the physics of the very small
Directly related questions
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20N.3.HL.TZ0.24b:
Identify two possible causes of the anisotropies in (a).
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20N.3.HL.TZ0.24b:
Identify two possible causes of the anisotropies in (a).
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20N.3.HL.TZ0.b:
Identify two possible causes of the anisotropies in (a).
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17N.3.HL.TZ0.20c:
Show that the critical density of the universe is
where H is the Hubble parameter and G is the gravitational constant.
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17N.3.HL.TZ0.20c:
Show that the critical density of the universe is
where H is the Hubble parameter and G is the gravitational constant.
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17N.3.HL.TZ0.c:
Show that the critical density of the universe is
where H is the Hubble parameter and G is the gravitational constant.
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18M.3.HL.TZ1.19c:
Explain, using the equation in (a) and the graphs, why the presence of visible matter alone cannot account for the velocity of stars when r > R0.
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18M.3.HL.TZ1.19c:
Explain, using the equation in (a) and the graphs, why the presence of visible matter alone cannot account for the velocity of stars when r > R0.
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18M.3.HL.TZ1.c:
Explain, using the equation in (a) and the graphs, why the presence of visible matter alone cannot account for the velocity of stars when r > R0.
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18M.3.HL.TZ1.19b:
Draw on the axes the observed variation with r of the orbital speed v of stars in a galaxy.
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18M.3.HL.TZ1.19b:
Draw on the axes the observed variation with r of the orbital speed v of stars in a galaxy.
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18M.3.HL.TZ1.b:
Draw on the axes the observed variation with r of the orbital speed v of stars in a galaxy.
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18M.3.HL.TZ2.19b:
Outline why a hypothesis of dark energy has been developed.
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18M.3.HL.TZ2.19b:
Outline why a hypothesis of dark energy has been developed.
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18M.3.HL.TZ2.b:
Outline why a hypothesis of dark energy has been developed.
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18N.3.HL.TZ0.21b:
The present temperature of the cosmic microwave background (CMB) radiation is 3 K. Estimate the size of the universe relative to the present size of the universe when the temperature of the CMB was 300 K.
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18N.3.HL.TZ0.21b:
The present temperature of the cosmic microwave background (CMB) radiation is 3 K. Estimate the size of the universe relative to the present size of the universe when the temperature of the CMB was 300 K.
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18N.3.HL.TZ0.b:
The present temperature of the cosmic microwave background (CMB) radiation is 3 K. Estimate the size of the universe relative to the present size of the universe when the temperature of the CMB was 300 K.
- 18N.3.HL.TZ0.20b: State two candidates for dark matter.
- 18N.3.HL.TZ0.20b: State two candidates for dark matter.
- 18N.3.HL.TZ0.b: State two candidates for dark matter.
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18N.3.HL.TZ0.21a:
Show that the temperature of the universe is inversely proportional to the cosmic scale factor.
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18N.3.HL.TZ0.21a:
Show that the temperature of the universe is inversely proportional to the cosmic scale factor.
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18N.3.HL.TZ0.a:
Show that the temperature of the universe is inversely proportional to the cosmic scale factor.
- 19M.3.HL.TZ1.20a: Light from distant galaxies is redshifted. Explain the cosmological origin of this redshift.
- 19M.3.HL.TZ1.20a: Light from distant galaxies is redshifted. Explain the cosmological origin of this redshift.
- 19M.3.HL.TZ1.a: Light from distant galaxies is redshifted. Explain the cosmological origin of this redshift.
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19M.3.HL.TZ1.20b.ii:
Compare and contrast, the variation with time of the temperature of the cosmic background (CMB) radiation, for the two models from the present time onward.
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19M.3.HL.TZ1.20b.ii:
Compare and contrast, the variation with time of the temperature of the cosmic background (CMB) radiation, for the two models from the present time onward.
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19M.3.HL.TZ1.b.ii:
Compare and contrast, the variation with time of the temperature of the cosmic background (CMB) radiation, for the two models from the present time onward.
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19M.3.HL.TZ2.22b:
At critical density there is zero total energy. Show that the critical density of the universe is: .
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19M.3.HL.TZ2.22b:
At critical density there is zero total energy. Show that the critical density of the universe is: .
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19M.3.HL.TZ2.b:
At critical density there is zero total energy. Show that the critical density of the universe is: .
- 19M.3.HL.TZ2.22c: The accepted value for the Hubble constant is 2.3 × 10−18 s−1. Estimate the critical density of...
- 19M.3.HL.TZ2.22c: The accepted value for the Hubble constant is 2.3 × 10−18 s−1. Estimate the critical density of...
- 19M.3.HL.TZ2.c: The accepted value for the Hubble constant is 2.3 × 10−18 s−1. Estimate the critical density of...
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19N.3.HL.TZ0.16b(ii):
Calculate the density of matter in the universe, using the Hubble constant 70 km s–1 Mpc–1.
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19N.3.HL.TZ0.16b(ii):
Calculate the density of matter in the universe, using the Hubble constant 70 km s–1 Mpc–1.
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19N.3.HL.TZ0.b(ii):
Calculate the density of matter in the universe, using the Hubble constant 70 km s–1 Mpc–1.
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17N.3.HL.TZ0.20b:
Suggest how fluctuations in the cosmic microwave background (CMB) radiation are linked to the observation that galaxies collide.
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17N.3.HL.TZ0.20b:
Suggest how fluctuations in the cosmic microwave background (CMB) radiation are linked to the observation that galaxies collide.
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17N.3.HL.TZ0.b:
Suggest how fluctuations in the cosmic microwave background (CMB) radiation are linked to the observation that galaxies collide.
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18M.3.HL.TZ1.19a:
The mass of visible matter in the galaxy is M.
Show that for stars where r > R0 the velocity of orbit is v = .
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18M.3.HL.TZ1.19a:
The mass of visible matter in the galaxy is M.
Show that for stars where r > R0 the velocity of orbit is v = .
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18M.3.HL.TZ1.a:
The mass of visible matter in the galaxy is M.
Show that for stars where r > R0 the velocity of orbit is v = .
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18M.3.HL.TZ2.19a:
Explain the evidence that indicates the location of dark matter in galaxies.
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18M.3.HL.TZ2.19a:
Explain the evidence that indicates the location of dark matter in galaxies.
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18M.3.HL.TZ2.a:
Explain the evidence that indicates the location of dark matter in galaxies.
- 18N.3.HL.TZ0.20a: Outline what is meant by dark energy.
- 18N.3.HL.TZ0.20a: Outline what is meant by dark energy.
- 18N.3.HL.TZ0.a: Outline what is meant by dark energy.
- 19M.3.HL.TZ1.20b.i: Draw, on the axes, a graph to show the variation with time of the cosmic scale factor R for the...
- 19M.3.HL.TZ1.20b.i: Draw, on the axes, a graph to show the variation with time of the cosmic scale factor R for the...
- 19M.3.HL.TZ1.b.i: Draw, on the axes, a graph to show the variation with time of the cosmic scale factor R for the...
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19M.3.HL.TZ2.22a:
Justify that the total energy of this particle is .
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19M.3.HL.TZ2.22a:
Justify that the total energy of this particle is .
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19M.3.HL.TZ2.a:
Justify that the total energy of this particle is .
- 19N.3.HL.TZ0.16b(i): State what is meant by the critical density.
- 19N.3.HL.TZ0.16b(i): State what is meant by the critical density.
- 19N.3.HL.TZ0.b(i): State what is meant by the critical density.
- 19N.3.HL.TZ0.16b(iii): It is estimated that less than 20 % of the matter in the universe is observable. Discuss how...
- 19N.3.HL.TZ0.16b(iii): It is estimated that less than 20 % of the matter in the universe is observable. Discuss how...
- 19N.3.HL.TZ0.b(iii): It is estimated that less than 20 % of the matter in the universe is observable. Discuss how...
- 20N.3.HL.TZ0.21c: Hubble originally linked galactic redshift to a Doppler effect arising from galactic recession....
- 20N.3.HL.TZ0.21c: Hubble originally linked galactic redshift to a Doppler effect arising from galactic recession....
- 20N.3.HL.TZ0.c: Hubble originally linked galactic redshift to a Doppler effect arising from galactic recession....
- 20N.3.HL.TZ0.24a: State the nature of the anisotropies observed in the CMB radiation.
- 20N.3.HL.TZ0.24a: State the nature of the anisotropies observed in the CMB radiation.
- 20N.3.HL.TZ0.a: State the nature of the anisotropies observed in the CMB radiation.
- 21N.1.SL.TZ0.30: Which is correct for a black-body radiator? A. The power it emits from a unit surface area...
- 21N.1.SL.TZ0.30: Which is correct for a black-body radiator? A. The power it emits from a unit surface area...