Astronomy is the scientific study of celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, meteoroids, asteroids, and comets.

Astronomy has been practiced since ancient times, and its roots can be traced back to civilizations such as Mesopotamia, Egypt, Greece, and China. These early astronomers made observations of the night sky with the naked eye and simple instruments. They used these observations to track the movements of the planets, stars, and other celestial objects. They also developed theories about the structure and origin of the universe.

In the 17th century, the invention of the telescope revolutionized astronomy. With this instrument, astronomers were able to see celestial objects in much greater detail. They discovered new planets, moons, and stars. They also made important observations of the Milky Way Galaxy and the nebulae.

In the 20th century, astronomy continued to advance rapidly. Astronomers developed new technologies such as radio telescopes, infrared telescopes, and space telescopes. These technologies allowed them to study celestial objects in new ways. They made important discoveries about the universe, including the existence of quasars, pulsars, and black holes. They also discovered that the universe is expanding at an accelerating rate.

Today, astronomy is one of the most exciting and active fields of science. Astronomers are using new and powerful telescopes to explore the universe in greater detail than ever before. They are making new discoveries about planets, stars, galaxies, and black holes. They are also trying to answer some of the most fundamental questions about the universe, such as how it was formed and what its ultimate fate will be.