A bronze disk, at the size of an analog disc turntable is showing that people of the Bronze Age had constructed calculating astronomical instruments.
In the summer of 1991 a group of antiquities, investigating with metal detector on top of a low hill near the town of Nebra in central Germany, 60 km west of Leipzig, revealed a small archaeological treasure. Among jewelry, tools and weapons of the Bronze Age found a bronze disc, diameter 32 cm, which brought unusual performances formed with gold leaf: a circle, a crescent, three curved lines and many dots that looked like stars in the night sky.
Physicists made dating examined traces of organic materials of swords found with the disk and concluded that they were aged about 3,600 years ago. The chemists, on the other hand, examined the content of bronze and gold in minerals concluded that copper was by an ancient mine in Central Austria and gold from the Carpathian Mountains. Therefore the disc was transferred from another part of Europe, but was built on the spot even before 1600 BC .It was not so easy to determine if they were decorative or a utilitarian object.
Legend of the Pleiades
Driven by the golden shapes that reminded the Sun, Moon and Stars, archaeologists thought to consult an astronomer, Professor Schlosser (Wolfhard Schlosser) at the University of Bochum. Professor Schlosser tried to compare the positions of the “star” of the disc with the various positions of stars in modern astronomical maps, but without success. Obviously they had a decorative character. He did, however, struck by the fact that seven of the “stars” of the disc seemed to form a separate group, and this led to the idea that this group represents the Pleiades, a star cluster that people call as Birds. With current telescopes we know that this flock has thousands of stars, but to the naked eye we can distinguished only seven.
The Pleiades is one of the most distinctive bodies in the night sky and mentioned several times in the Old Testament and in epic poetry. Homer and Hesiod said the west of the Pleiades just after sunset (the Gregorian calendar around 3 November) signaled the deterioration of the weather and the end of the sea voyage. It also marks the end of agricultural work, in view of the winter.
The arcs of the Sun
If the disc “captured ” astronomical knowledge of the people of the Bronze Age , then the corresponding factor should have gold and other shapes. Professor Schlosser found that two of the three curves, those are just around the disc, and forming arcs of 80 degrees each. For an astronomer that number is “significant “because it is equal to the arc defining the region of Nebra points of sunrise during the winter and summer solstice.
Most probably know that in the summer the sun rises from the southeast and northeast of the winter, but they are probably not aware that the range between these two positions is a function of latitude. In the area of Greece is about 60 degrees, but in central Germany is 80 degrees. Therefore it seems that the two curves represent the disc one range of arc sunrise in different seasons and the other, symmetrically, the range of arc west.
This interpretation should be documented and the study of the horizon from the top of the hill where the disc was found. Are there any landmarks in positions from where the sun rises at the summer and winter solstice? Unfortunately, this question was not easy to answer, because of the Bronze Age has changed the vegetation in the area and that there were no shrubs today, there are tall trees that block the view of the horizon. But with the help of a Geographic Information System (GIS) surveyors of the research team were able to prove that really the days of the solstices the sun rise and was setting behind characteristic peaks of mountains surrounding the Nebra.Finally, archaeologists believe that the third curve line that found inside the disc represents schematically the ship in which the Sun makes the daily journey from East to West and in the East again. This representation is common among people who lived in Denmark and southern Sweden during the Bronze Age. So the collaboration of archaeologists, physical, chemical and surveyor manages to give a first comprehensive interpretation of the disc of Nebra.
It is about a primitive astronomical instrument that served to identify the characteristics the start and finish of agricultural work!