Astronomy is a natural science that is the study of celestial objects such as moons, planets, stars, nebulae, and galaxies, the physics, chemistry, and evolution of such objects, and phenomena that originate outside the atmosphere of Earth, including supernovae explosions, gamma-ray bursts, and cosmic microwave background radiation


A collection of planet sized objects including  the star sirius. These are all objects of the study of astronomy, including the place of Earth in space. Image: wikipedia

Astronomy is one of the oldest sciences.

Prehistoric cultures have left astronomical artifacts such as the Egyptian monuments and Nubian monuments, and early civilisations such as the Babylonians, Greeks, Chinese, Indians, Iranians and Maya performed methodical observations of the night sky. 

The telescope



A replica of Isaac Newton's second reflecting telescope of 1672, Cambridge. image: wikipedia


Observational astronomy

 is focused on acquiring data from observations of astronomical objects, which is then analyzed using basic principles of physics.  This includes basic observations of the movement of the sun (for example observations of the solstice and equinox), moon, stars and planets.


The Hubble space telescope in orbit. image: NASA/wikipedia

Theoretical astronomy



A computer simulation showing the result of a simulation of the collision of two disk galaxies, run using the NEMO package. image: wikipedia

Amateur astronomy



The word "astronomy" comes from the Greek "aster" meaning star and the suffix "_nomy" meaning "laws of" the Greek word nomos means law or rule.