Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties (luminosity, density, temperature, and chemical composition) of celestial objects such as galaxies, stars, planets, exoplanets, and the interstellar medium, as well as their interactions.
This is the nuts and bolts stuff (much of which overlaps with Astronautics) that's most likely to matter in a space-faring Sci Fi game.
- Atmospheric Reentry
- Escape Velocity
- In Space No One Can Hear You Roll The Dice
- Lagrange Points
- Movement of the Earth
- Space Exposure
- Stellar Classification
- Temperature Of Outer Space
- Big Bang
- Brane cosmology
- Cosmic inflation
- False Vacuum
- General relativity
- Newton's law of universal gravitation
- Lambda-CDM model
- Rare Earth Hypothesis
- Astronomers Find Gaping Hole In The Universe
- Comet Holmes Bigger Than The Sun
- 'Cosmic ghost' discovered by volunteer astronomer
- "Hot" Comets The Source Of Life?
- LCROSS Impact Data Indicates Water On Moon
- Nearby Pulsating Star Cloud Puzzles Astronomers
- Newfound Planet Orbits Backwards
- Precious Gems Discovered On Mars
- Physicists Find Evidence That The Universe Is A 'Giant Brain'
- Strange Methuselah Star Looks Older Than the Universe
Game and Story Use
- Understanding the way the cosmos works can really help you GM Speculative Fiction games without making obvious mistakes.
- In particular, the links under the heading "Practical Astrophysics" cover most of the things likely to come up in sci-fi scenarios. Don't try to leave orbit without them!
- The Interstellar Terrain page has links to various interstellar phenomenon, celestial bodies, and megastructures. Useful if you need a hazard, destination, or scenery.