The observed universe
Unseen matter, cosmic expansion, energetic particles, and brief radio flashes.
40 problemsCollections
Selected problems that share a subject or a research tradition. Each leads to its own overview and sources.
Within Astrophysics · All collections
Inside planets and stars
Composition, structure and internal dynamics of planets and stars.
37 problemsStellar explosions
How stars explode, what they leave behind, and where heavy elements form.
5 problemsStars and stellar remnants
Rotation, magnetic fields, cluster chemistry and the remnants of stellar evolution.
14 problems