(CNN) The Nebra sky disc, one of Germany's most heralded prehistoric artifacts, is often considered the world's oldest depiction of the cosmos. For a relatively small object -- the gold-speckled disc is only 12 inches wide -- it has produced a large amount of controversy.
In fact, the Nebra sky disc's sordid history reads like a Dan Brown novel, involving looters, court hearings, conflict between archaeologists and even allegations of revenge.
The sky disc was reportedly unearthed in 1999 near the town of Nebra, Germany, by looters who sold it to black-market dealers. It was recovered by law enforcement several years later, and the looters were prosecuted in court. Today, it's exhibited in the State Museum of Prehistory in Halle.
But there were inconsistencies in the looters' stories about how they acquired the artifact. And experts continue to debate the exact origins and history of the disc, which is widely considered to be from the Bronze Age, about 3,600 years ago.
Now, the saga continues as a new analysis has suggested the Nebra sky disc could be about 1,000 years younger than previously thought.
Based on analysis of the soil attached to the disc and the iconography of its decorations, two scientists concluded that the artifact is more likely to be from the Iron Age, dating between about 2,800 and 2,050 years ago. The study published this month in the German journal Archaeological Information.
The authors of the study, Rupert Gebhard, director of the Bavarian Archaeological State Collection in Munich, and Rüdiger Krause, professor of prehistory and early European history at Goethe University Frankfurt, argued the exact location of the disc's discovery might not be the Mittelberg hill near Nebra, Germany -- the spot where one looter directed authorities.
"One principle of the looters is to never tell the truth about the site you have excavated," Gebhard said. "What's interesting is that nobody has discovered anything on the Mittelberg before this discovery, and nobody has discovered anything on the Mittelberg after. From this point of view, it's highly unusual that the site is the real site."
The date of the disc was determined in part by the objects found alongside it -- Bronze Age swords, axes and a prehistoric chisel. But based on soil attachments found on all the objects, the authors wrote, it's also not certain they were originally found together.
The new study casts doubt on the artifact's status as the oldest depiction of the heavens and could tarnish its reputation as what UNESCO has called "one of the most important archaeological finds of the 20th century."
The German state of Saxony-Anhalt, which hosts the disc in its state museum, is strongly refuting Gebhard and Krause's research.
"The colleagues not only ignore the abundance of published research results in recent years, their various arguments also are easily refuted," Deputy State Archaeologist Alfred Reichenberger said in a statement, adding that some of the claims in the new research article are inconsistent and "not comprehensible."
Ernst Pernicka, a professor of natural archaeology at the University of Tübingen, said that he and the director of the State Museum, Harald Meller, plan to publish a rebuttal paper later this year.
Pernicka told CNN he believed the new analysis could even be "revenge" because Gebhard and Krause once published a book on Mycenaean gold artifacts found in Bavaria, but Pernicka's analysis concluded they were fakes.
Pernicka's earlier research on the disc found that the composition of the copper of the sky disc and the copper of the objects found alongside it are all very similar. His research also determined the soil below the Mittelberg spot where the disc was reportedly found has enrichments of copper and gold that prove those metals had been buried there for a long time -- strong arguments against the latest analysis, he said.
The State Office for Heritage Management and Archaeology argued that the soil attachments on the sky disc and the objects found nearby it "very probably" correspond with the presumed location where the looters said the objects were found, citing yet another expert who conducted the investigations of the soil attachments for the Regional Court of Halle.
Both sides said the other scientists are ignoring crucial expert opinions and pieces of evidence.
Emilia Pásztor, an archaeologist at Hungary's Türr István Museum who has studied the disc but is unaffiliated with the latest analysis and the state museum, told CNN she believed that both sides' analyses regarding the soil samples are not clear enough. However, she said the scientific community is excited about the debate and the possibility of new investigations.
"The Nebra disk -- due to the circumstances of the discovery -- belongs to those archaeological finds that can be debated forever until some very accurate absolute dating method can be found for metals by physicists or other nature-scientists," Pásztor said in an email.
Pásztor also said the latest analysis of the iconography found on the disc is "not complete and convincing" enough to definitively place it in the Iron Age, but that the very simple style of the imagery also differs from usual depictions from the Bronze Age. The crescent shape was extremely rare during that time period, she also noted, and only one other late Bronze Age artifact (a bowl from Zurich) has one.
"All these arguments are not solid evidences," Pásztor noted, adding, "If an archaeological find is taken from a treasure hunter to a museum, one cannot be sure of anything."
There have even been discussions in the past about whether the artifact is a forgery.
But the museum put the artifact through rigorous testing to ensure it's not a fake, and Pernicka told CNN that tests on the metal have definitively confirmed it's at least 100 years old -- so not a modern forgery. However, existing technology isn't good enough prove whether it's from the Bronze or Iron age. Gebhard and Krause also said they think it's "an original object of unknown date," adding that "the Iron Age is the most probable date -- it even could be younger."
Gebhard said the important things is for archaeologists to be clear about what they do and do not know for certain.
"Of course we know there is a political aspect, as well as a scientific aspect," said Gebhard, adding that the disc generates tourism for Saxony-Anhalt and the state has invested large sums of money into its museum exhibit. "Archaeology itself is not as precise as physics or chemistry. There are always errors and misinterpretations and the problem is you have to be honest to say, 'Well, I know this but I don't know this.'"
It's important for the scientists studying the disc to be upfront with local authorities and museum visitors that there could be other interpretations and evidence, Gebhard said.
"We're trying to set up a scientific discussion, finally, to get into the topic again together with other colleagues and with the Halle colleagues," Krause added. "It's a very interesting artifact, but it needs more open discussion."