Astrophysics is physics let loose on the largest stage there is. The same laws you meet in a laboratory — gravity, thermodynamics, nuclear reactions, quantum statistics — run stars, sculpt galaxies, and set the fate of the whole universe. A star is a self-regulating ball of plasma balancing its own crushing gravity against the fury of fusion in its core; get that balance right on paper and you can predict how bright it shines and how it will die.

This branch takes the intuitive picture from Earth & space and makes it quantitative: the equations of stellar structure, how the elements are forged, the exotic physics of white dwarfs, neutron stars and black holes, the dark matter that binds galaxies, and the expanding, cooling universe traced back to its first light.