Astronomy is a natural science that studies astronomical phenomena and celestial bodies. Astronomy uses mathematics, physics, and chemistry to explain the origin and evolution of those phenomena and objects. Objects of interest include planets, moons, stars, nebulae, galaxies, and comets. Related phenomena include supernova explosions, gamma-ray bursts, quasars, glowing quasars, pulsars, and the cosmic microwave background radiation. In general, astronomy studies everything that originates outside the Earth's atmosphere. Cosmology is a branch of astronomy. He studies the cosmic space as a whole.

Astronomy is one of the oldest natural sciences, and early civilizations in recorded history made systematic observations of the night sky. These include the Babylonians, Greeks, Indians, Egyptians, Chinese,