Astrophysics is a branch of astronomy that focuses on understanding the physical properties and behavior of celestial objects and phenomena. It combines principles from physics and mathematics to study the universe, including stars, planets, galaxies, and black holes. Astrophysicists seek to explain how these entities form, evolve, and interact. One of the key areas of research in astrophysics is the study of dark matter and dark energy, which make up most of the universe's mass-energy content. By observing light and other forms of radiation, scientists can gather data to test theories about the universe's origins, structure, and ultimate fate.