Commonly Asked Questions in Physics

Chapter 10

Astrophysics and Cosmology

Physics has long been applied to study astronomical objects, first in our solar system and then throughout the universe. It was thinking about how the moon moves around Earth and how the planets move around the sun that led Newton to develop his law of gravity in the late seventeenth century. Newtonian gravitation gives a good account of the motion of large bodies in the universe, and where Newton’s theory falls short, it has been improved upon by Einstein’s theory of general relativity. Better observational techniques in the eighteenth, nineteenth, and twentieth centuries allowed astronomers and astrophysicists to expand their studies well beyond our solar system—to more distant stars and eventually to ...