Astronomy is the very old study of general science, which dates back to the pre-historic times. Astronomy began with mythology, religion, calendrical study and in cosmology and with the practices and beliefs of the pre-historic times: A surviving trace of these exist in astrology, a guideline which intermingled with the astronomy of government and the public for a considerable period of time, with not much of separation till some centuries before in the western world. Certain cultures make use of the data of astronomy for the prognostication of astrology (prophesying future events)
Earliest astronomers could find the difference between planets and stars, because planets move to a great distance within a short time, whereas stars are relatively static for years.
Early History of Astronomy
According to the age old beliefs, celestial objects were considered as spirits and Gods. These objects were referred to (along with their position) as certain phenomena like seasons, drought, tides and rain. The general notion was that the original astronomers were priests, who considered celestial objects and their corresponding actions as evidence of divinity; this is the reason why astrology is related to the early astronomy. Prehistoric constructions with astronomic relevance (like Stonehenge) perhaps were complete during social, astronomical and religious ceremonies.
The world over, calendars were repeatedly prepared taking into consideration the Moon and Sun (signifying the day, month and the year), they were of importance to those of the agricultural families, where their harvest was based on sowing on the definite period of the year. The calendar currently in use is on the basis of the Roman calendar, the months based on the phases of the moon were cancelled, which was traditionally practiced and the year was divided into 12 months, which comprises of 30 and 31 days alternatively. In BC 46, Julius Caesar brought about reforms in the calendar, presently called the Julian calendar, which has its base as 365and quarter day in a year this was the original suggestion of the Greek astronomer Callippus in the 4th century BC
Archeological Excavations That Brought Light to the Evolution of Astronomy
Ever since 1990, our predictions of the ancient Europeans have been altered from the grass root levels, in spite of findings of pre-historic astronomical artifacts all over Europe. The artifacts reveal that the Bronze Age and Neolithic Europeans possessed knowledge developed to a high degree of complexity of astronomy and mathematics.
Some of the discoveries considered are as follows:
- The Scotland’s Aberdeen shire’s River valley, which was originally excavated in the year 2004, was disclosed as a finding of great implication only in the year 2013, currently, it is the oldest calendar of the world formed about 8000 BC and it predates the rest of the calendars around 5000 years. This calendar has the appearance of the past Mesolithic (the culture during Neolithic and Paleolithic) monument which has a stretch of 12 pits that assists the person monitoring to position the lunar months by imitating the phases of the moon. Besides, it brings into alignment with the sunrise during the winter solstice; in this way it coordinates the lunar cycles with the solar year.
- The Goseck circle is situated in Germany, which was originally discovered in the year 1991 is a part of the pottery culture. It was in the year 2004 when the archeological discoveries were accessible that its significance was made apparent. The site comprises of one in hundred among the comparable circular enclosed spaces, constructed in a province encircling Germany, Austria and the Czech Republic in the course of 200 years beginning immediately following 5000 BC.
- The Nebra sky disc, made of bronze dates back to the Bronze Age, it was hidden in Germany, close to the Goseck circle, approximately in 1600 BC. The diameter of the disc is almost 30 cm and it has a mass of 2.2 kg., having a bluish-green glaze (through oxidization) embedded with golden symbols. The archeological thief discovered it in 1999 and it was recovered in the year 2002 in Switzerland. Immediately it was documented as a stunning discovery, one of the crucial discoveries of the 20th On further investigation, it was found that the disc was made use of almost 400 years prior to its burial (around 200 BC), however, when it was buried; there was no record of its use.
The embedded gold portrayed the full moon, as a semicircular moon around 4 to 5 days of age, the cluster of the Pleiades star bunch configured in a particular orientation, with the original appearance which portrays celestial phenomenon. In the span of 354 days, there will be 12 lunar months, in which it will be possible to fix a leap month after every 2 or 3 years, so as to synchronize it with the seasons (forming lunisolar) of the solar year It was in the 6th or 7th century BC, that the explanation of this was explained by the Babylonians. Thereafter, those explanations proved pre-historic information about the celestial depiction of the Nebra sky disc, which indicates the exact orientation required to decide upon the insertion of the intercalary month within a lunisolar calendar, which will turn into an astronomical clock, which regulates the calendar for more than 1000 years, until another device is established.
- The Kokino site which was revealed in 2001, takes the position on top of the vanished volcanic cone, situated at a height of 1,013 m (3,323 ft.), it occupies around 0.5 hectares, having an overall view of the scenery in the Republic of Macedonia. Towards 1900 BC, during the Bronze era, an astronomical observatory was built over there, it was helpful for the people around there till around 700 BC
- The central location was intended for observing the rising of the Sun and for observing the Full Moon. There were three indications to locate the sunrise during solstices of winter and sunrise of summer and both the equinoxes.
- The fourth marking indicates the maximum and a minimum downward inclination of the full moon in winter and summer.
- Two of it gives the lengths of lunar months.
In the configuration of the 235 lunation, that takes place in the 19 solar years, for adjusting the lunar calendar, the astronomers combine the lunar and solar cycles.
Golden hats of France, Germany and Switzerland from 1400 to 800 BC correlate with that of the Bronze Age Urn-field culture. The Golden hats are ornamented with a spiral shaped motif of the Moon and the Sun. Perhaps they act as a calendar for determining the solar and lunar calendars
Astronomy in Ancient Mesopotamia
Mesopotamia is the place of inception of the Western astronomy, the land joining the rivers “Euphrates and Tigris”, this was the place where the primitive kingdoms of Assyria, Sumer and Babylonia were situated. It was nearing 3500 to 3000 BC that a type of writing called Cuneiform materialized from the Sumerians.
The knowledge we have about the Sumerian astronomy is not direct, which is by means of the old Babylonian star catalogues as early as 1200 BC. The truth that stars are named differently in Sumerian, recommends a nonstop process that reaches the old Bronze Age. It is, the Sumerians that initiated the astral theology, where planetary Gods were given a significant place in the Mesopotamian Mythology and also in religion. Besides, they made use of a sexagesimal (base 60) system of place-value number. Sexagesimal made easy the job of making records of big numbers and infinitesimally small numbers. The current method of splitting a circle into 360 degrees each of 60 minutes, started with the Sumerians.
The Indian Perspective
- The subcontinent of India relating to astronomy started at the time of the Indus Valley Civilization, in 3000 BC, it was at that time meant for preparing calendars. The Indus-Saraswati civilization topped the world in technology and science in 3000 BC; it also led the world in philosophy and trade. There were no written credentials set aside by the Indus Valley Civilization; therefore the Vedanga Jyotisha became the earliest extant Indian astronomical text, which started from the Vedic era. It is the Vedanga Jyotisha that explains certain regulations for tracing the movement of the Moon and the Sun for determining rituals. Astronomy was prejudiced by the Byzantine and Greek traditions in astronomy in AD 600.
- Aryabhata (476 to 550), used his magnum opus, called Aryabhatiya (499), put forward a method of calculation, which was based on a planetary model. Here, he considered the Earth rotates on its axis. The Sun was considered as the center of reference for calculating the periods of the planets.
- It was at the time of the Shunga that the study of Astronomy progressed, at that time Empire and several star catalogues were generated. “In India, the Shunga era was called the Golden age of astronomy”. During this age, we experienced the progress of calculations taken to determine the positions and movement of different planets, the rising and setting of the planets their combinations, also the computation of eclipse
- Bhāskara 11 (1114 to 1185) at Ujjain, became the supreme in astronomical observations, progressing in the mathematical practice of Brahmagupta. He too computed the duration for the Earth to orbit about the sun, correcting the time to 9 decimal places. During this period, the Buddhist University of Nalanda proposed prescribed courses in the study of astronomy.
- Nilakantha Somayaji, Madhava and Jyeshtadeva, were also famous Indian astronomers. They were associates of the Kerala School of Astronomy and Mathematics, dating from the fourteenth century to the sixteenth century.
- Astronomy was established by the early Greeks, they considered it a section of mathematics, of a very high standard. Eudoxus of Cnidusand of Cyzicus of the 4th century, was the first to give an explanation for the geometrical, 3 dimensional model, showing the perceptible movement of the planets.
- Aristotle and Plato gave more importance in detailing the causes for the cosmos motion than creating mathematical models of prediction.
- Aristarchus of Samos of the third century took the initial steps in considering a heliocentric system, even though just partial explanation of the idea continues to exist.
- The premier model proposed that a smaller circle was obtained by eccentric circle moving around, this was named epicycle, the credit of which goes to Apollonius of Perga, The second century BC Hipparchus of Nicea, conducted an advanced study on this.
It was around 150 to 100 BC that the age old Greek astronomers used the Antikythera mechanism, an appliance for observing and calculating the motions of the Moon and the Sun, perhaps the planets too. Besides, they were the forerunners who introduced the astronomical computer. The discovery was done in a very old shipwreck from the Greek island called Antikythera, situated between Crete and Kythera.
The exact compass reading of the Egyptian pyramids requires a lifelong manifestation of precise technical proficiency in observing the heavens achieved in 3000 BC. They observed the pyramids in line with the pole star, this was on account of the exactness of the equinoxes, the then Thuban, which was a faded star found in the Draco constellation.
Assessing the location of the Amun-Re temple at Karnak while considering the shift in the time of the obliquity of the ecliptic, led to the conclusion that the Great Temple was in line with the rising of the mid- winter sun. The path of the sunlight across the passage had restricted light during the remaining periods of the year.
- A very crucial point for establishing the yearly calendar was the rising of Sirius (in Greek: Sothis, in Egyptian: Sopdet) when the flood began.
- Clement of Alexander subscribed gave few clues of significance of astronomical watching to the sacred rituals.
- The Chinese maintained a prolonged history of astronomy. Accurate observations were maintained beginning of the sixth century BC, as far as the inception of the telescope in the 17th century and the Western astronomy. Chinese astronomers could exactly predict eclipses.
- The reason why Chinese conducted study on astronomy, was mainly for scheduling time. They made use of a lunisolar calendar; The Moon and the Sun have different cycles, therefore most of the time the astronomers made fresh calendars and observations connected to it.
- In the fourteenth century BC, a Chinese astronomer by the name Gan De, made the world’s first catalogue of stars.
Astronomy in Medieval Islam
- The Islamic astronomers contributed much importance on observational astronomy, consequently, in the beginning of the ninth century; they emerged in finding the premier astronomical observation in the Muslim World. These observations were entered in the Zij star catalogue came into being in these observatories.
- Towards the end of the tenth century, Abu-Mahmud Khujandi, a famous astronomer, built a great observatory adjacent to Tehran, in Iran. He then made several observations of the meridian movement of the Sun; by this he was able to compute the tilt of the earth’s axis with respect to the Sun.
Science in the Middle Ages
- Western Europe stepped into the Middle Ages with difficulty; this caused problems in the sensible analysis of astronomy. The sophisticated treaties in astronomy in classical antiquity were of Greek writings, with scarce understanding of that language, the study material was limited to practical texts and simplified summaries.
- Towards the ninth century, elementary computations related to the location of the planets were distributed in Western Europe.
- In the tenth century, European scholars like Gerbert of Aurillac initiated his journey to Sicily and Spain in search of knowledge.
- Towards the twelfth century, scholars made a voyage to Sicily and Spain in search of highly developed texts on astrology and astronomy; they made a translation of the same into Latin, Greek and Arabic.
- The rebirth of astronomy by the contribution of Nicolaus Copernicus, led to the proposition of a heliocentric arrangement, here the planets orbit round the Sun, not the Earth.
- Galileo was given the status of the father of observational astronomy. He was the premier in the use of a telescope for observing the sky, he then developed a 20x refractory telescope, following the finding of the 4 biggest moons of Jupiter in 1610. This was the earliest surveillance of the satellites orbiting a different planet.