Meaning of Astronomy:
The word astronomy is derived from the Greek astronomia. Literally it means “law of the stars” (astron for “star” and nomos for “laws or culture”). In general, astronomy refers to the study of the physical and chemical properties of objects and matters outside Earth’s atmosphere. Below are some of top astronomy facts for space enthusisats:
Ancient Astronomy Facts:
click to enlarge
• The Antikythera mechanism was the oldest known astronomical device. This ancient Greek device was used between 150-80 B.C. for calculating a planet’s movement. The device was discovered off the Greek island of Antikythera in an ancient shipwreck. Revered as the first ancestor of the astronomical computer, the Antikythera mechanism had some very modern features. The complexity of its bronze parts was similar to an 18th century clock. The device became popular for its use of a differential gear, which was previously believed to have been invented in the sixteenth century.
• Ancient Babylonian astronomers applied mathematics to their predictions on any astronomical phenomena. The oldest written evidences of celestial phenomena were the ancient Babylonian cuneiform tablets called as Enuma Anu Enlil. Of these astronomical texts, Tablet 63, known as the Venus tablet of Ammisaduqa, records the visible risings of planet Venus over the period of 21 years. This was the earliest reference about planetary phenomena.
• The writings of Homer and Hesiod included references about identifiable stars and constellations. In the classic Iliad and Odyssey, Homer refers to many constellations including Ursa Major, Orion, Pleiades, Bootes and Sirius, the Dog Star.
• The name “planet” is derived from the Greek term planetes, meaning “wanderer”.
• Ancient Greeks thought that the morning and evening appearances of planet Venus represented two different objects. When Venus appeared in the eastern morning sky, it was called Phosphorus, or “light-bringer”. When it appeared in the western evening sky, it was thought to be an “evening star” and was called Hesperus.
• The geocentric model entered Greek astronomy in the 4th century BC. During this period, educated Greeks thought that Earth was
click to enlarge
at the center of the universe and the Sun, Moon, stars and other planets surrounded Earth. But, earlier theories about the heliocentric model were completely ignored. The earliest reference to a heliocentric model of the solar system was made in the 3rd century BCE by Aristarchus of Samos! Aristarchus is also known as the “Greek Copernicus”.
• The Indian astronomer Aryabhata’s (476-550 CE) writings greatly influenced Islamic astronomy. Aryabhata, in his books, Āryabhatīya and the Aryabhatasiddhanta, plainly mentioned that the earth rotated around its own axis. Aryabhata also stated that the moon shines because of reflected sunlight.
(Image, top left: The Antikythera mechanism from the ship wreck courtesy: http://en.wikipedia.org/wiki/File:NAMA_Machine_d%27Anticyth%C3%A8re_1.jpg)
(Image, Bottom Right: Classic illustration of the Ptolemaic geocentric model of the universe by Bartolomeu Velho, from his work Cosmographia, France, 1568, image courtesy of:http://en.wikipedia.org/wiki/File:Bartolomeu_Velho_1568.jpg)
