Astronomy is the scientific study of celestial objects, such as stars, planets, galaxies, and other phenomena in the universe. It explores their composition, structure, and behavior, as well as the physical laws that govern them. Astronomers use telescopes, both on the ground and in space, to observe and study celestial objects. The universe is vast and expanding, consisting of billions of galaxies, each containing billions of stars. Stars are massive, luminous balls of gas that generate energy through nuclear fusion. Astronomy plays a critical role in advancing our understanding of the cosmos and our place within it.