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Astronomy & Astrophysics

What is out there, how we know, and the physics that makes stars shine, galaxies turn and the universe expand.

For: anyone who has looked up and wondered, amateur astronomers, anyone thinking of studying astronomy or astrophysics, and physics readers who want to see their subject at the largest scale.

Shaped by the American Astronomical Society's guidance for undergraduate astronomy, the UK Institute of Physics degree accreditation framework and programmes such as MIT's Course 8 astrophysics track and Caltech's Ay courses; figures are dated and sourced to NASA, ESA, the IAU and survey papers.

17readings
3.6 hoursof reading
4stages
15 reads · 2 deep dives
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Stage 1

Year 1 · The language

4 readings · 42 min
  1. 01ReadInteractiveQuiz10 min

    Calculus I: Slopes, Totals and the Bridge Between Them

    Calculus: orbits, light curves and expansion are rates of change.
  2. 02ReadInteractiveQuiz10 min

    Physics I: Mechanics — Three Ways to Keep the Books

    Mechanics: gravity and orbits start here.
  3. 03ReadInteractiveQuiz10 min

    Physics II: Electricity & Magnetism — Charge, Fields and Light

    Electricity and magnetism: light is an electromagnetic wave.
  4. 04ReadInteractiveQuiz12 min

    The Sky & Observational Astronomy: Where Everything Is, and What You Can See

    Finding your way around the sky and what the eye and a small telescope show.
Stage 2

Year 2 · Light and instruments

4 readings · 56 min
  1. 05ReadInteractiveQuiz13 min

    Waves and Optics: When Waves Add, Light Can Make Darkness

    Waves and optics: how telescopes and spectra work.
  2. 06ReadInteractiveQuiz14 min

    Telescopes, Light & Spectra: Everything We Know Arrives as Light

    Everything we know arrives as light (and now gravitational waves).
  3. 07ReadInteractiveQuiz13 min

    Special Relativity: Everyone Gets the Same Speed of Light

    Special relativity: fast particles and the speed limit.
  4. 08Deep diveInteractiveQuiz16 min

    Planetary Science & Exoplanets: Worlds by the Thousands, Read from a Dip in Light

    The Solar System and the thousands of worlds around other stars.
Stage 3

Year 3 · Stars

4 readings · 50 min
  1. 09ReadInteractiveQuiz12 min

    Quantum Mechanics: Waves of Probability and the Limits of Knowing

    Quantum mechanics: spectral lines and nuclear fusion.
  2. 10ReadInteractiveQuiz11 min

    Statistical Mechanics: Temperature Is What Counting Looks Like

    Statistical mechanics: gases, radiation and the inside of a star.
  3. 11ReadInteractiveQuiz13 min

    Particle & Nuclear Physics: What Stuff Is Made Of, and What Can Happen to It

    Nuclear and particle physics: what makes stars shine.
  4. 12ReadInteractiveQuiz14 min

    Stars: Structure & Evolution: Balance Sheets of Weight, Heat and Time

    How stars are built, live and die.
Stage 4

Year 4 · Galaxies and the universe

5 readings · 1.2 hours
  1. 13ReadInteractiveQuiz14 min

    Galaxies & the Milky Way: Island Cities of Stars, Weighed by Their Spin

    Our galaxy and the others, and the dark matter in them.
  2. 14ReadInteractiveQuiz12 min

    General Relativity: Gravity Is the Shape of Spacetime

    General relativity: gravity as geometry.
  3. 15Deep diveInteractiveQuiz18 min

    Compact Objects & High-Energy Astrophysics: The Densest Things and the Hardest Light

    White dwarfs, neutron stars, black holes and the violent universe.
  4. 16ReadInteractiveQuiz13 min

    Astrophysics & Cosmology: Reading the Universe from Light Alone

    Cosmology: the universe's history and fate.
  5. 17ReadInteractiveQuiz14 min

    Astronomical Data & Computation: Counting Photons, Finding Rhythms, Building Pictures

    Modern astronomy is a data science.
When you finish

the textbooks named at the end of each subject; NASA's and ESA's open data archives; Stellarium (free planetarium software). See also the library's Physics major.

Study it in depth, for free

These pieces give you the intuition. To learn the major properly, these are the courses and texts universities use, free to read or audit, and the standard textbooks if you want to own one. Links checked November 2026.

The whole major, free: MIT OCW Physics department listing · take 8.01 mechanics, 8.03 waves, 8.04 quantum, then the astronomy sequence below (8.282J, 8.284, 8.901, 8.902, 8.286, 8.962), using the textbooks to fill in the mathematics.

Free courses and texts

  1. Classical Mechanics (8.01SC) · MIT OCW, 8.01SC · forces, energy and orbits; Year 1
  2. Physics III: Vibrations and Waves (8.03SC) · MIT OCW, 8.03SC · waves and optics behind telescopes and spectra; Year 2
  3. University Physics Volume 1 (free textbook) · OpenStax · mechanics, gravitation and waves; Year 1
  4. Astronomy 2e (free textbook) · OpenStax · a full introductory astronomy text, sky to cosmology; Year 1
  5. Introduction to Astronomy (8.282J) · MIT OCW, 8.282J · stars, galaxies, cosmology for non-specialists; Year 1-2
  6. The Science of the Solar System · Caltech via Coursera (Mike Brown) · planets, moons and how we study them; free, with no certificate; Year 2
  7. Hands-On Astronomy: Observing Stars and Planets (12.409) · MIT OCW, 12.409 · practical observing and instruments; Year 2
  8. Quantum Physics I (8.04) · MIT OCW, 8.04 · the quantum mechanics behind spectra and stellar physics; Year 2-3
  9. Modern Astrophysics (8.284) · MIT OCW, 8.284 · stars, compact objects, galaxies; Year 3
  10. Astrophysics I (8.901) · MIT OCW, 8.901 · stellar structure and interstellar medium; Year 3
  11. Astrophysics II (8.902) · MIT OCW, 8.902 · galaxies and cosmology; Year 3-4
  12. The Early Universe (8.286) · MIT OCW, 8.286 · Big Bang cosmology; Year 4
  13. General Relativity (8.962) · MIT OCW, 8.962 · black holes and gravitational waves, advanced; Year 4

The standard textbooks

  • Astronomy 2e (OpenStax, free legal PDF) · introductory survey for self-learners
  • An Introduction to Modern Astrophysics (Carroll and Ostlie) · the standard upper-level astrophysics text
  • Fundamental Astronomy (Karttunen et al.) · compact survey of observation and theory
  • University Physics (Young and Freedman) · the physics foundation, Year 1-2
  • Introduction to Cosmology (Ryden) · the standard undergraduate cosmology text
  • Astrophysics for People in a Hurry (Neil deGrasse Tyson) · short popular overview for self-learners
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Finance & Accounting

How money is counted, checked, taxed, invested and priced, and how the financial system holds together or breaks.