An illicit discovery
In the summer of 1999, two treasure hunters, Henry Westphal and Mario Renner, were illegally scanning the top of Mittelberg hill near Nebra, Germany, with a metal detector. They were not archaeologists. They were looters, and when their machine pinged, they dug hastily. Their spade struck something hard, chipping the edge of a bronze disk and dislodging one of its inlaid gold stars. Alongside the disk, they unearthed two bronze swords with gold-banded hilts, two hatchets, a chisel, and fragments of spiral armlets. This collection, now known as the Nebra hoard, was the property of the state of Saxony-Anhalt, but Westphal and Renner sold the entire find to a dealer in Cologne for 31,000 Deutsche Marks.
For two years, the disk circulated on the international black market, its price inflating to one million DM. Its existence became public knowledge in 2001, and in February 2002, the object was recovered. Harald Meller, the state archaeologist, participated in a police sting operation at the Hilton Hotel in Basel, Switzerland, where authorities seized the disk from a couple attempting to sell it. The looters were eventually caught and sentenced. The recovered disk was not a forgery, as some initially suspected; micro-photographic analysis of its patina and soil deposits confirmed it was an authentic artifact buried at the Mittelberg site.
A portable cosmos
The Nebra Sky Disk is a bronze plate with a blue-green patina, measuring about 30-32 centimeters in diameter and weighing 2.2 kilograms. The bronze itself is an alloy of copper from the Austrian Alps and tin from Cornwall, UK. Its surface is inlaid with gold symbols depicting the cosmos as understood around 1600 BCE, making it the oldest known depiction of astronomical phenomena in the world.
The disk's design was modified over time, showing a developing understanding of the sky. In its first phase, it featured a large circle (interpreted as the sun or a full moon), a crescent moon, and 32 small gold dots representing stars. A tight cluster of seven of these dots is widely identified as the Pleiades. The arrangement of the Pleiades relative to the moon on the disk corresponds to their appearance in the sky in the spring and autumn, marking the planting and harvest seasons in the Bronze Age.
In a second phase, two golden arcs were added to the disk's edges. These arcs span an angle of 82 degrees, which precisely matches the angle between the sunset's position on the horizon at the summer and winter solstices at the latitude of Mittelberg hill. This addition transformed the disk from a seasonal calendar into a more sophisticated astronomical instrument for tracking the solar year. A final addition was a third arc at the bottom, interpreted as a "sun boat" carrying the sun across the night sky, a common motif in Bronze Age mythology. Before it was buried, around 39 holes were punched into its perimeter, possibly for mounting it.