Astronomy-The Way To Explore The Outer Space
The science which deals with the study of celestial objects like stars, planets, comets, star clusters and galaxies is said to be Astronomy. Astronomy is concerned with the evolution of celestial objects, as well as the formation and development of the universe. The word astronomy is derived from the Greek words “astron” which means star and “nomos” which means “law” or “culture”. Astronomy basically means that the law of the stars. In the early days our ancestors identified celestial objects with gods. They related the movements of the celestial objects to various phenomena like rain, drought, seasons and tides.
On the basis of the movement of the sun and moon they calculated their days, month and year and formed their calendar. In early days our ancestors believed earth is at the center of the universe where as the sun and other celestial objects are rotating around it. Now we call it as the geocentric model of the Universe. Aristarchus of Samos proposed a Heliocentric Model of the Solar System in the 3rd century BC.The first person who described the details of the motion of the planets with Sun at the center was Johannes Kepler. He was not able to succeed in formulating a theory. Kepler’s work led to the invention of Celestial Dynamics by Newton. In 1781 Uranus Planet was discovered by William Herschel. In 20th century the existence of the Separate group of stars called Milky Way was proved along with the existence of other galaxies.
Astronomy is classified into two types namely observational and theoretical Astronomy. The Observational Astronomy comprises of Radio astronomy, infra-red astronomy, Optical astronomy, X-ray astronomy, Gamma-ray astronomy. There are also some specific sub-fields like solar astronomy, galactic astronomy, etc.The closest star to the earth is the Sun. The study of the sun is known as the Solar Astronomy. The astronomers try to understand the formation of the stars by looking at the sun. The studying of sun also helps the people to understand the working principle of the nuclear fusion because nuclear fusion occurs at the center of the sun. The periodic changes in luminosity of sun can have a significant impact on the Earth.
The study of planets, their satellites, comets and asteroids are known as the planetary astronomy, whereas the study of various galaxies is known as the Galactic astronomy. These studies are conducted by the help of spacecraft, telescopes and computer simulations. There are various instruments used by astronomers are Telescopes, Spectrometers and Satellites. The year 2009 was declared as the International Year of Astronomy in the 62nd General assembly of the UN. The intention of the IYA 2009 is the global celebration of astronomy and its contributions to society and culture. Indians have a great knowledge in the field of astronomy dating back from the older days. Indians were the first to establish that the Earth rotates around the Sun much before the likes of Copernicus, Kepler and many others could prove it. Now in the domain of Space exploration in India is in at par with that of USA,USSR and other countries around the world.