A celestial body refers to any natural object outside Earth's atmosphere that exists in space, such as planets, moons, asteroids, comets, and stars.
Solar System: A solar system consists of a star (like our Sun) and all the celestial bodies orbiting around it.
Galaxy: A galaxy is a vast collection of stars, gas clouds, dust particles, and other celestial bodies held together by gravity.
Universe: The universe encompasses everything that exists - all matter and energy including galaxies, stars, planets, and other celestial bodies.