Topic 4: Cosmology
4.1 The birth, life and death of the universe
Nature of science:
Occam’s Razor: The Big Bang model was purely speculative until it was confirmed by the discovery of the cosmic microwave background radiation. The model, while correctly describing many aspects of the universe as we observe it today, still cannot explain what happened at time zero.
Understandings:
The Big Bang model
Cosmic microwave background (CMB) radiation
Cosmological redshift
Hubble’s law
Hubble’s constant and the age of the universe
The cosmological principle
Olbers’ paradox
Applications and skills:
Describing both space and time as originating with the Big Bang
Explaining how redshift data indicates the universe is expanding and how this leads to the idea of the Big Bang
Describing the characteristics of the CMB radiation
Explaining how the CMB radiation is evidence for a Hot Big Bang
Solving problems involving Hubble’s law
Estimating the age of the universe by assuming a constant expansion rate
4.2 Large scale structures in the universe
Nature of science:
Observation: As the amount of data increases as a result of more detailed observations our understanding of the universe also increases.
Understandings:
Galactic distribution
Galactic clusters
Local groups
Superclusters
Walls of galaxies, including the Great Wall
The galactic arrangement in the universe
Applications and skills:
Explaining the distribution of galaxies within the universe to include rich and poor clusters
4.3 The shape of spacetime
Nature of science:
Paradigm shift: Over time there have been a number of different theories of gravitation and some of these have led to a major change in our understanding of the world around us.
Understandings:
The ancient Greeks
Galileo Galilei and falling objects
Isaac Newton and the universal law of gravitation
Albert Einstein and General Relativity
The effect of gravity is equivalent to the acceleration of an object
Relativistic ideas about time and space can be reconciled by describing these things together as four-dimensional spacetime
Geometries for spacetime
Know that the Big Bang theory of cosmology raises questions
Inflation
Applications and skills:
Understanding the development of ideas of gravitational forces
Understanding the consequences of the possible geometries of spacetime
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