Human: Can you tell me about the history of astronomy? Assistant: 
Astronomy is the study of celestial objects and phenomena, including planets, stars, galaxies, nebulae, comets, asteroids, and meteorites. The earliest astronomers were ancient civilizations such as the Babylonians, Greeks, Chinese, Indians, and Egyptians. They observed the sky and recorded their observations in various ways, including through the use of calendars, star maps, astrolabes, and other instruments. In the Middle Ages, Islamic scholars developed sophisticated observational techniques that allowed them to make more precise measurements of the positions of stars and planets. In the 15th century, Nicolaus Copernicus proposed a heliocentric model of the solar system, which was later refined by Galileo Galilei and Johannes Kepler. In the 19th century, Edwin Hubble discovered that the universe is expanding, and that it contains many galaxies beyond our own Milky Way galaxy. Today, modern telescopes and space probes are used to study the universe in greater detail.