Astronomy is the science that is responsible for studying everything related to the stars, their movements and the laws that govern them. The word, as such, comes from the Latin astronomy, and is in turn from the Greek ἀστρονομία.
Astronomy studies the celestial bodies of the universe, from planets and their satellites, through comets and asteroids and to the systems of interstellar matter, dark matter, stars, gas and dust that we know as galaxies. As such, it is the science of the physical universe and the phenomena that occur in it.
The branches of astronomy are astrophysics, which studies the characteristics of celestial bodies; the position astronomy, which measures and determines the position of the stars; the celestial mechanics, which focuses on the movement of the stars; and cosmology, which theorizes about the formation and evolution of the universe.
Astronomy has been part of the history of mankind since ancient times. Civilizations such as the Aztec, the Mayan and the Inca, as well as the Egyptian, the Chinese and the Greek reached such a degree of knowledge that they are considered fundamental for the subsequent evolution of the discipline. In this sense, it is considered the oldest science, and has been essential in the development of other scientific disciplines, such as mathematics or physics.
In its beginnings, astronomy had a practical application to know the cycles of the stars and establish time measures that allowed determining, among other things, the right time for sowing and harvesting.
Some astronomers of great importance in history have been Claudio Ptolemy, Nicholas Copernicus, Johannes Kepler and Galileo Galilei.
Astronomy and astrology
Although astronomy and astrology in the beginning were terms that could be used as synonyms, today they designate well differentiated disciplines. At present, astronomy has developed as a scientific discipline that deals with the study of the stars, their movement and the laws that govern them, while astrology was maintained over time as a system of beliefs and superstitions related with the influence attributed to the movement of the stars on the character of people and historical events. Both sciences were separated and differentiated from the Renaissance, thanks to the predominance of rationalist thinking.