Edexcel IGCSE Physics topic guide
Astrophysics questions
Explore orbital motion, follow the life cycles of stars, and connect astronomical observations to evidence for an expanding universe.
Astrophysics topic overview
Astrophysics studies gravity and orbits, the scale of the universe, stellar evolution and evidence for the Big Bang.
Use the correct astronomical scale, connect observations to physical conclusions, and distinguish what happens to Sun-like stars from the evolution of more massive stars.
Question types in astrophysics
- Orbital speed, radius, period, weight and gravitational-field calculations.
- Comparisons of planetary, lunar, comet and satellite orbits.
- Stellar temperature, colour, life-cycle and Hertzsprung-Russell diagram questions.
- Red-shift, cosmic microwave background and expanding-universe explanations.
Astrophysics subtopics
Choose a subtopic for its syllabus points, answering guidance and worked exam questions.
8.a Units
Gravitational field strength, force, mass and units used in orbital calculations.
8.b Motion in the universe
Planets, satellites, stars and galaxies, with gravitational forces and orbital motion.
8.c Stellar evolution
Star colour and temperature, stellar life cycles and the fate of different-mass stars.
8.d Cosmology
Red-shift, the expanding universe and the evidence supporting the Big Bang.