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Led by Georges Lemaître Simulacrum
Four tutorials covering AQA GCSE Physics §4.8 Space Physics — our solar system, the life cycle of stars, orbits and satellites, and red-shift and the Big Bang — taught by simulacra of the astronomers and cosmologists who have mapped our place in the universe.
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Led by Carl Sagan Simulacrum
The question
What is in our solar system, where did it come from, and what is our place in the universe?
Territory
our solar system contains one star (the Sun), eight planets, dwarf planets, and their natural satellites (moons) · the solar system as a small part of the Milky Way galaxy · the Sun was formed from a nebula — a cloud of dust and gas — pulled together by gravitational attraction · gravity causing the nebula to collapse · at the core, the temperature and pressure ignite nuclear fusion reactions · fusion releases energy that pushes outward · an equilibrium is reached between gravitational collapse and fusion-driven expansion · this equilibrium defines the main-sequence life of a star
Outcome
The student can name the structure of the solar system (Sun, planets, dwarf planets, moons) and its place in the Milky Way, explain that stars form by gravitational collapse of a nebula, and describe the equilibrium between gravitational collapse and fusion-driven expansion that defines a star's main-sequence life. (AQA 4.8.1.1)
Led by William Herschel Simulacrum
The question
How does a star end, and where did the atoms in your body come from?
Territory
a star's life cycle is determined by its mass · two tracks: Sun-sized and much more massive than the Sun · for a Sun-sized star: nebula → main sequence → red giant → planetary nebula + white dwarf → black dwarf (after cooling) · for a star much more massive than the Sun: nebula → main sequence → red super-giant → supernova → neutron star or black hole · fusion processes in stars produce all of the naturally occurring elements · elements heavier than iron are produced in supernovae · the supernova distributes the elements throughout the universe · the consequence: subsequent generations of stars and planets (including ours) contain heavy elements
Outcome
The student can describe the life cycle of a Sun-sized star and of a much more massive star with all the spec-named stages, explain how fusion processes form the naturally occurring elements, and explain why heavier-than-iron elements exist only because earlier stars died in supernovae. (AQA 4.8.1.2)
Led by Johannes Kepler Simulacrum
The question
Why does the Moon not fall onto the Earth, and why does the International Space Station need to travel at 28,000 km/h?
Territory
gravity provides the force that maintains circular orbits for planets and satellites · natural satellites (moons) and artificial satellites · similarities and differences between planets, moons, and artificial satellites · (HT) in a circular orbit, gravity changes velocity (direction) but not speed · (HT) gravity does no work on a satellite in circular orbit because the force is perpendicular to the motion · (HT) for a stable orbit, if the speed changes, the radius must change · (HT) faster orbital speed → smaller radius; slower orbital speed → larger radius · worked examples: the Moon, geostationary satellites, low-Earth orbit (e.g. the International Space Station), the planets
Outcome
The student can describe how gravity provides the force for orbits, distinguish natural from artificial satellites, and (Higher Tier) explain that in a circular orbit the force of gravity changes velocity but not speed, and that a change in orbital speed requires a change in orbital radius. (AQA 4.8.1.3)
Led by Georges Lemaître Simulacrum
The question
The universe is expanding, and it began. How do we know these two things, and what does it mean that there is still so much we do not understand?
Territory
the observed increase in wavelength of light from most distant galaxies · further galaxies show greater red-shift · red-shift as evidence that space itself is expanding · the Big Bang theory: the universe began from a very small, extremely hot, extremely dense region · the observed accelerating expansion (supernova observations since 1998) · how red-shift provides evidence for the Big Bang model · how scientists use observations to arrive at theories like the Big Bang · the frontier: dark mass (missing matter that holds galaxies together but does not emit electromagnetic radiation) and dark energy (the cause of the accelerating expansion) — much about the universe is still not understood
Outcome
The student can explain qualitatively the red-shift of light from receding galaxies, describe the relationship between a galaxy's speed and its distance as evidence of expansion, explain how red-shift provides evidence for the Big Bang model, and articulate the open questions about dark mass and dark energy. (AQA 4.8.2)