Nebra sky disk



The Nebra Sky Disk is a bronze disk of around 30 cm diameter, with a blue-green patina and inlaid with gold symbols. These are interpreted generally as a sun or full moon, a lunar crescent, and stars (including a cluster interpreted as the Pleiades). Two golden arcs along the sides, marking the angle between the solstices, were added later. A final addition was another arc at the bottom surrounded with multiple strokes (of uncertain meaning, variously interpreted as a Solar Barge with numerous oars, as the Milky Way or as a rainbow).

The disk is attributed to a site near Nebra, Saxony-Anhalt in Germany, and associatively dated to c. 1600 BC. It has been associated with the Bronze Age Unetice culture.

The disk is unlike any known artistic style from the period, and had initially been suspected of being a forgery, but is now widely accepted as authentic.

Discovery
The disk appeared as if from nowhere on the international antiquities market in 2001. Its seller claimed that it had been looted by illegal treasure hunters with a metal detector in 1999. Archaeological artifacts are the property of the state in Saxony-Anhalt and following a police sting operation in Basel, Switzerland, the disk was acquired by the state archaeologist, Dr Harald Meller. As part of a plea bargain, the illicit owners led police and archaeologists to the site where they had found it together with other remains (two bronze swords, two hatchets, a chisel and fragments of spiral bracelets). Though no witnesses were present at the first discovery, archaeologists have opened a dig at the site and have uncovered evidence that support the looters' claim (in the form of traces of bronze artifacts in the ground, as well as matching earth samples found sticking to the artifacts). The disk and its accompanying finds are now in Halle in the Landesmuseum für Vorgeschichte (State Museum for Prehistory) of Saxony-Anhalt, Germany. The two looters received a four months and a ten months sentence by a Naumburg court in September 2003. An appeal court raised these to six and twelve months, respectively.

The discovery site identified by the arrested metal detectorists is a prehistoric enclosure encircling the top of a 252 m elevation in the Ziegelroda Forest, known as Mittelberg ("central hill"), some 60 km west of Leipzig. The surrounding area is known to have been settled since the Neolithic, and Ziegelroda Forest is said to contain around 1,000 barrows.

The enclosure is oriented in such a way that the sun seems to set every solstice behind the Brocken, the highest peak of the Harz mountains, some 80 km to the northwest. It was claimed by the treasure-hunters that the artifacts were discovered within a pit inside the bank-and-ditch enclosure.

The signifiance of the site to prehistoric dwellers is underlined by the proximity to the much older Goseck circle.

Dating
The precise dating of the Nebra skydisk depended upon the dating of a number of Bronze Age weapons, which were offered for sale with the disk and said to be from the same site. These axes and swords can be typologically dated to the mid 2nd millennium BC (Unetice culture). Radiocarbon dating of a birch bark particle found on one of the swords to between 1600 and 1560 BC confirmed this estimate. This corresponds to the date of burial, at which time the disk had likely been in existence for several generations.

According to an analysis of trace elements by x-ray fluorescence by E. Pernicka, at the time University of Freiberg, the copper originated at the Mitterberg in Austria, while the gold is from the Carpathian Mountains. Copper from Bottendorf in the immediate vicinity of Nebra has definitely not been used. But few copper objects are found where they were originally smelted.

History
The disk as preserved was developed in four stages (Meller 2004):
 * 1) Initially the disk had thirty-two small round gold circles, a large circular plate, and a large crescent-shaped plate attached. The circular plate is interpreted as either the Sun or the full Moon, the crescent shape as the crescent Moon (or either the Sun or the Moon undergoing eclipse), and the dots as stars, with the cluster of seven dots likely representing the Pleiades.
 * 2) At some later date, two arcs (constructed from gold of a different origin, as shown by its chemical impurities) were added at opposite edges of the disk. To make space for these arcs, one small circle was moved from the left side toward the center of the disk and two of the circles on the right were covered over, so that thirty remain visible. The two arcs span an angle of 82°, correctly indicating the angle between the positions of sunset at summer and winter solstice at the latitude of the Mittelberg (51° N). Given that the arcs relate to solar phenomena, it is likely the circular plate represents the Sun not the Moon.
 * 3) The final addition was another arc at the bottom, the "sun boat", again made of gold from a different origin.
 * 4) By the time the disk was buried it also had thirty-nine or forty holes punched out around its perimeter, each approximately 3 mm in diameter.

Significance
Possibly an astronomical instrument as well as an item of religious significance, the disk is a beautiful object; the blue-green patina of the bronze may have been an intentional part of the original artifact.

If authentic, the find reconfirms that the astronomical knowledge and abilities of the people of the European Bronze Age included close observation of the yearly course of the Sun, and the angle between its rising and setting points at summer and winter solstice. While Stonehenge and the Neolithic "circular ditches" such as the 5th millennium BC Goseck circle were used to mark the solstices, the disk is the oldest known "portable" instrument to allow such measurements.

Another view is that the Nebra disk can be linked to the solar calendar reconstructed by Alexander Thom from his analysis of standing stone alignments in Britain. MacKie has argued that several aspects of the disk support this view, following up the work of Prof. Wolfhard Schlosser. The first is that the Mittelberg – the hill on which the disk is supposed to have been found – is so situated that when the sun sets at two distant mountain peaks in the north-west, both midsummer and May Day are accurately marked (and therefore also the old Celtic harvest festival on Aug. 2nd);  these are three important dates in the 16 'month' Thom solar calendar. The second feature is the two golden arcs on either side of the disk which subtend angles of about 82 degrees;  this is the angular distance between  sunrise and sunset at midsummer and midwinter at the latitude of Mittelberg. This surely implies a detailed knowledge of the yearly solar cycle on the part of the disk's designer. The third feature is the 32 golden 'star spots' on the disk. Although Thom found really clear evidence for only sixteen subdivisions of the solar year (of 21 or 22 days) in the standing stone alignments, there were some indications of a further subdivision into 32 parts of 10 or 11 days.

Authenticity
There were initial suspicions that the disk might be an archaeological forgery. Peter Schauer of the University of Regensburg, Germany, argues that the Nebra disk is a fake. He is quoted as saying:
 * "If you urinate on a piece of bronze and then hide it in the ground for a few weeks you can produce the same patina as on the disk."

Richard Harrison, professor of European prehistory at the University of Bristol and an expert on the Beaker people allowed his initial reaction to be quoted in a BBC documentary:
 * "When I first heard about the Nebra Disc I thought it was a joke, indeed I thought it was a forgery. Because it’s such an extraordinary piece that it wouldn’t surprise any of us that a clever forger had cooked this up in a backroom and sold it for a lot of money."

Though Harrison had not seen the skydisk when he was interviewed, it was a reasonable skepticism at that point, but the disk is now widely accepted as authentic and dated to roughly 1600 BC on grounds of typological classification of the associated finds. As the item was not excavated using archaeological methods, even its claimed provenance may be made up, hence authenticating it has depended on microphotography of the corrosion crystals (see link), which produced images that could not be reproduced by a faker.

Dr Harald Meller, lecturing to the Society of Antiquaries of Scotland in April 2008, gave a list of reasons for the authenticity of the disc and for its find spot being on the Mittelberg. The most persuasive of the latter was the discovery by the archaeologists – in the pit in which the looters said they had found the metalwork – of a fragment of gold leaf which exactly fits the gap which existed in the gold leaf covering on the 'sun' symbol when it was originally recovered.

Exhibition
The disk was the center of an exhibition titled Der geschmiedete Himmel ("the smithied heavens"), showing 1,600 Bronze Age artifacts, including the Trundholm sun chariot, shown at Halle from 15 October 2004 to 22 May 2005, from 1 July to 22 October 2005 in Kopenhagen, from 9 November 2005 to 5 February 2006 in Vienna, from 10 March to 16 July 2006 in Mannheim and from 29 September 2006 to 25 February 2007 in Basel.

On 20 June 2007 a multimedia visitor center was opened near the discovery site at Nebra.

Legal issues
The state of Saxony-Anhalt has registered the disk as a trademark, which has resulted in two lawsuits. In 2003, Saxony-Anhalt successfully sued the city of Querfurt for depicting the disk design on souvenirs. In an ongoing (as of 2006) lawsuit, Saxony-Anhalt is suing the publishing houses Piper and Heyne over an abstracted depiction of the disk on book covers. The Magdeburg court is required to assess the case's relevance according to German copyright law. The defenders argue that as a cultic object, the disk had already been "published" in the Bronze Age, and that consequently all protection of intellectual property associated with it has long expired. The plaintiff on the other hand argues that the editio princeps of the disk is recent, and according to German law protected for 25 years, or until 2027. Another argument concerns the question whether a notable work of art may be registered as a trademark in the first place.

Popular culture
The disk has begun to attract the kind of pseudoarchaeology, neopagan and paranormal speculation that is associated with Stonehenge and Arkaim. The Nebra Skydisk is also the name of an experimental band out of Binghamton, New York.