2009Europa - Astronomy - Sheetlets

Astronomy is the science about observing and explaining appearances in space, studies origin, development, physical and chemical characteristics of celestial bodies: stars, planets, constellations, black holes, comets and other objects in the space. It is probably one of the oldest sciences, in the earliest period of time human civilization people used to, from their need or curiosity, observed different celestial bodies and its movement, first the Sun and the Moon, and later other planets, stars and constellations. Word astronomy came from the old Greek and in the translation means "Law about stars". First astronomy had range to the point that human eye could see, later many technical tools came into the usage and these are today sophisticated so much that many celestial bodies could be even if they are millions light quantum years away from the planet Earth. Many branches were developed like astrobiology, astrometry, cosmology, galactic astronomy and many others. According to the manner of space exploration, depending on a part of electromagnetic spectrum which helps in observing, astronomy can be optical, infrared, radio, roentgen astronomy etc.