Astronomy is the study of all celestial objects. It is the study of almost every property of the Universe from stars, planets and comets to the largest cosmological structures and phenomena. Astronomy is the oldest of the natural sciences. In fact astronomical observations laid the foundation of modern sciences. Early astronomy involved observing the regular patterns of the motions of visible celestial objects, especially the Sun, Moon, stars and the planets like Jupiter, Saturn and Mars. The changing position of the Sun along the horizon or the changing appearances of stars in the course of the year was used to establish agricultural or ritual calendars.
Astronomers around the world study the working of the Universe. Majority of astronomical objects are far and faint. Astronomers have access to limited information about their nature. Large and powerful instruments of high resolution and sensitivity are needed for astronomical observations. Astronomers combine different types of observations to infer conclusions. Astronomers observe electromagnetic waves from all parts of the spectrum. Every type of visible and invisible light reveals a different piece of the great cosmic puzzle. Today, this is being done through a combination of many disciplines and sub-fields using many different approaches. The various tools and techniques include: Ground-based telescopes, Space based observatories, Robotic probes and Theoretical calculations and simulations. Astronomers study the Universe not only to further our understanding of the cosmos, but to advance other fields of science and technology too. Astronomy consists of a series of disciplines including:
Solar astronomy: Studies of our own star, the Sun
Planetary science: Studies of the bodies in our own Solar System and those in orbit around other stars,
Stellar astronomy: The study of stars and stellar evolution
Galactic astronomy: The study of our own Milky Way and its evolution
Extragalactic astronomy: The study of objects outside of our Milky Way
Cosmology: The study of the Universe as a whole.
Some interdisciplinary studies include
Astrobiology: The study of the advent and evolution of biological systems in the Universe
Archaeoastronomy: The study of ancient or traditional astronomies in their cultural context, utilising archaeological and anthropological evidence
Astrochemistry: The study of the chemical constitution of objects in space
Fundamental research is a stand-alone process that is done because it is deemed valuable by society and civilization. It often occurs on very long timescales and satisfies a deeply rooted curiosity in humans. Advances in astronomical and space science technology, brought about by applied research in astronomy, can often have a greatly beneficial effect on humankind after 50 or 100 or even more years. Today millions of people worldwide are affected by the short and long-term advances made in astronomy and space science. Some astronomical results, or derivatives of astronomical research, can be transferred to technological advances. The examples include: The development of CCD detectors, Image processing techniques, Satellite Communication Techniques and Development of Robotics. Astronomy is also useful for Agriculture, Nautical Navigation, Solar Architecture, Climate research and Weather forecasting. The seasons are main markers in the agricultural calendar and for centuries astronomical observations determined when to sow and when to harvest. Knowledge of the tides induced by the Sun and the Moon is very important to the all ocean-going traffic. In earlier times measurements of the position of the Sun, Moon, stars and planets in the sky were the only way of knowing a ship’s position at sea. This skill still comes handy in case of instrument failure. Awareness of the Sun's daily path across the sky is crucial for the design of energy efficient -buildings, to achieve proper light and temperature conditions. This is important in wake of energy and environment crisis. Manmade climate changes are at the top of scientific and political agendas, but need to be disentangled from certain astronomical phenomena that have long-term influences on Earth’s climate. The variability of the amount of solar radiation changes the total energy input to the Earth’s atmosphere. The variability of the solar ultraviolet emission affects the ozone layer and the temperature on Earth. High energy particle affects the ozone layer. Cosmic rays may affect cloud coverage. Understanding General Relativity enables us to fly planes, launch satellites or build GPS receivers. Thanks to advances in satellite technology we have more accurate weather forecasting. Thanks to accurate astrometry (positional astronomy) our satellites can fly through space knowing where they are. The search for Near Earth Asteroids and studies to understand them may one day help us in dealing with a dangerous meteorite.
Greatest Astronomical Discoveries of last century are:
The Milky Way is not the only galaxy in the Universe!
Discovery of Microwave Background Radiation!
The Universe is expanding!
The generation of stellar energy!
There are only two common types of stars – dwarfs and giants!
The composition of the ordinary matter in the Universe is understood!
Discovery of exotic objects – from pulsars and black holes to white dwarfs!
Presence of Dark Matter!
Presence of Extra-solar planetary systems!
Evidence of Solar neutrinos and helio-seismology !
It is no wonder that Nobel laureate C.V. Raman had remarked ‘there is no science so grand, so elevating, so intensely interesting as astronomy. Come on readers explore the marvels of the universe in International year of Astronomy 2009.
(With inputs from International Astronomy Union)
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