The Nazis were far from completing a working reactor for their atomic bomb program, despite claims by the project's leader that it was almost ready, a new study finds.

The German physicist Werner Heisenberg wrote in 1947 that the reactor for the "Nazi bomb" project ‪— which culminated in Germany's B8 nuclear reactor ‪— was almost finished at the end of World War II.

Heisenberg, who led the reactor's development, claimed the reactor was "just insufficient" to create a self-sustaining fission reaction and that it lacked only a "relatively small amount of uranium" to work.

If it had worked, the B8 reactor would have confirmed that a fission chain reaction was possible, marking a key step toward the German development of an atomic bomb. It could have also spurred the development of specialized fission reactors used to create weapons-grade plutonium from uranium. Instead, the atomic bomb was developed first by the United States and was used to force the surrender of Japan in August 1945. (Germany had already surrendered in May 1945.)

The new study, published Sept. 29 in the journal PNAS Nexus, used historical documents and forensic investigations of two of the project's surviving uranium cubes to refute Heisenberg's claim. The new research indicates that the German B8 reactor had less than half the amount of "heavy water" and about half the amount of uranium it would have needed for a continuous chain reaction.

"My results argue that Heisenberg was off by roughly a factor of two," said first author Patrick Park, a doctoral student at Princeton University who co-wrote the study while at Columbia University.

Park said Heisenberg's mistake was understandable: His calculations were only approximate, and the project was relocated to a rock cellar in the town of Haigerloch, Germany, after Berlin was bombed.

"People were dying or starving and so these reactor calculations were not his first priority," while many details of neutron physics were unknown at that time, Park told Live Science in an email. "Given these circumstances, I think he did the best he could."

Heavy water

To answer the question of how far the reactor for the Nazi bomb project got, the scientists began by tracing archival records of hundreds of uranium cubes that had been used by German scientists. The B8 reactor consisted of five concentric circles of uranium cubes suspended on chains within the heavy water tank. The German scientists planned to place a radium-beryllium neutron source into the reactor's core to kick-start the chain reaction with a flood of neutrons that would split the uranium nuclei and release more neutrons, furthering the chain reaction.

Heavy water is a form of water that contains the neutron-heavy hydrogen isotope deuterium. Like the mainly-graphite blocks and rods used in many reactors, it can be used to "moderate" or slow down fast neutrons created in a fission reaction so they trigger fission — and more neutrons — in nearby uranium atoms. The Germans also used small amounts of graphite in their reactor, but as a coating to reflect neutrons back into the chamber.

By combining the records of the cubes, heavy water and graphite used by the German scientists with measurements of the two surviving cubes, the study authors created a mathematical model of the reactor that agreed closely with historical measurements. This enabled them to establish that the heavy water reactor was far from achieving a stable reaction. The findings also helped them examine the suggestion that the Germans should have instead built a graphite-based reactor like the nuclear pile developed at the University of Chicago to build the American bomb.

But the study authors determined that a graphite-moderated reactor was unfeasible in wartime Germany because the local supply of coal available to create graphite contained high levels of neutron-absorbing boron, making it useless.

Instead, the heavy water used in the B8 reactor was produced at a single factory in Norway, which was occupied by Germany from April 1940 until May 1945. However, the reactor contained only about 370 gallons (1,400 liters) of heavy water, instead of the more than 780 gallons (roughly 3,000 liters) it would have needed, the researchers determined.

Heavy water makes up a tiny fraction of a percent of ordinary water, and extracting it by electrolysis in the Norwegian factory took extraordinary effort. The factory was producing as much heavy water as it could, but the B8 reactor would have needed more than twice the amount it produced during the entire war, the researchers wrote.

Another finding is that the B8 reactor had about half the amount of uranium it would have needed to sustain a fission chain reaction. The reactor contained a total of 664 cubes, each weighing about 5.11 pounds (2.32 kilograms), for a total of 3,390 pounds (1,540 kilograms) of uranium. Similar cubes were distributed among other experimental groups, giving a total inventory in wartime Germany of about 1,100 cubes of uranium.

But the researchers determined that the B8 reactor would have needed at least 1,200 cubes to work. Germany, therefore, was not about to develop a reactor for an atomic bomb in 1945. Contrary to Heisenberg's claims, the heavy-water reactor was not nearly ready, and a working graphite reactor was impossible.

"We conclude Germany could not have built heavy water nor graphite reactors during World War II," the researchers wrote.

Mark Walker, a historian at Union College in Schenectady, New York, who wasn't involved in the study, said the findings explain Germany's decision to develop a heavy-water reactor, since a graphite reactor was not feasible and they didn't know at the time how much heavy water would be needed.

Walker is the author of "Hitler's Atomic Bomb: History, Legend, and the Twin Legacies of Auschwitz and Hiroshima" (Cambridge University Press, 2024) and a noted expert on Germany's wartime nuclear efforts. He agreed that Germany could not have made a graphite reactor during World War II.

"This paper argues that if the Germans had done something they did not do, then this would have failed," he told Live Science in an email. "While this is counterfactual history, it is an interesting engineering analysis."

Archaeologists in southern Russia have unearthed the 2,000-year-old grave of an elite warrior who was buried with his weapons, horse — and a human sacrifice. The grave and sacrifices were found with other lavish goods, including two gold coins featuring Alexander the Great.

A team found the elite grave in Russia's Kuban region east of the Crimean Peninsula, in a necropolis of more than 150 ancient graves arranged around it. This central placement indicates the man had been a member of the social elite, according to the study, which was published in September in the journal Russian Archaeology.

The evidence of a human sacrifice comes from another burial assemblage beside the warrior's grave. This neighboring burial had the remains of three horses, two cattle, a pig, a dog and a fragment of a human pelvis that seems to have come from a sacrificed person, the researchers wrote.

The two gold coins — one found on the warrior's skeleton and one found nearby — indicate that the burial took place in the early first century B.C., while the location and style of the burial indicated the warrior had been a noble of the Indigenous Maeotian people. At that time, the Maeotians were allied with the neighboring Mithridatic Empire, a Hellenistic-Persian kingdom and the enemy of the expanding Roman Republic.

The researchers think the two gold coins were prestige items, rather than ordinary currency for commerce. "It is likely not money in the conventional sense, but rather a means of storing wealth, akin to a … cryptocurrency," study first author Mikhail Abramzon of the Institute of Archaeology at Russia's Academy of Sciences, told Live Science in an email.

Ancient gold

The two gold coins are key to the discovery. One was found in a ritual shaft near the burial in the center of the necropolis; the researchers think it was placed there as an offering to the gods.

The second was found beneath the jaw of the skeleton of the ancient warrior, which indicates it had been placed in the dead man's mouth before the burial and is an example of "Charon's obol" — the traditional ancient Greek payment for the mythical ferryman of the dead.

Both coins are gold "staters" in the Greek style adopted by Alexander the Great (who lived from 356 to 323 B.C.) and show portraits of Alexander.

Experts have determined that these coins were minted during the much later reign of Mithridates Eupator (lived 135 to 63 B.C.), also known as Mithridates the Great, who claimed descent from both Alexander and the Persian nobility and who initiated the three Mithridatic Wars with Rome. The Alexander portraits on the coins are designed to also look like Mithridates Eupator, the researchers wrote in the study.

According to the Greek geographer Strabo, writing in the first century A.D., the Maeotians were an Indigenous people integrated into the nearby Bosporan kingdom, a Greek and Scythian state founded on the north side of the Black Sea in the fifth century B.C. The Greek historian Appian, in the second century A.D., wrote that the Bosporan kingdom became part of the expanding Mithridatic Empire in the second century B.C. — and so the Maeotians were Mithridatic allies at the time of the burial in the first century B.C.

Grave goods

The warrior was buried with weapons — two iron spearheads and an iron arrowhead were found in his grave — as well as his riding gear and his horse, which had been sacrificed. The grave also held luxury items, including a rare glass "alabastron" — a small vessel for oil or perfumes, which had probably been imported from Cyprus or the Levant region of the eastern Mediterranean, the researchers wrote.

A two-handled clay cup, called a "kantharos" in ancient Greek, was also found in the grave. Its surface was engraved with a pentagram, a symbol of the sun, which the researchers think was considered spiritual protection against magical threats.

The researchers think the sacrifices in the nearby burial assemblages could have had different purposes. The cattle may have been offerings in the style of an ancient "hecatomb" — a mass slaughter of animals that would supposedly please a god. The horses were for riding in the afterlife, the pig was for eating in the afterlife, and the dog may have been intended to guide the dead warrior's spirit. The role of the human sacrificed with the animals is unknown, but it may have been to act as a servant for the warrior.

The researchers wrote that the coins and grave goods illustrate both the beliefs of the Maeotian people at this time, and the extent to which they had been influenced by the ancient Greek traditions of the neighboring Bosporon kingdom.

The largest hoard of Viking Age silver ever found in Finland — which contains almost 10 pounds (4.5 kilograms) of coins and jewelry — has been unearthed by a metal detectorist about 95 miles (150 kilometers) north of Helsinki.

The hoard had been divided into two deposits and buried in birch-bark containers. Although the coins and jewelry likely date to between A.D. 1000 and 1050, it's unknown exactly when they were buried, Esko Tikkala, an archaeologist at the Lahti Historical Museum who excavated the hoard, told Live Science in an email.

The hoard has not yet been fully cleaned, separated and counted yet, but there are thousands of pieces, Tikkala said. "There are quite a lot of coins in this hoard," he said. "I have not had time to go through them."

Metal detectorist Kalle Lappinen found the two deposits Sept. 3 and immediately contacted the museum. Archaeologists inspected and properly excavated the finds the next day, according to a translated statement.

Tikkala described the hoard site as beside a rock outcrop in a forest near the town of Sysmä. Several other buried hoards had been found in the same region of Finland over the past 10 years, Tikkala said.

Although it's challenging to determine why specific hoards were buried, a recent study of more than 15,000 Roman-era (the eighth century B.C. to the fifth century A.D.) hoards found that they were hidden for multiple reasons, including for tax evasion, votive offerings, and safe storage in times of uncertainty.

Tikkala said the two deposits of the silver hoard were buried between two stones about 18 inches (45 centimeters) below ground and about 39 feet (12 meters) apart. There were no signs of any burials nearby, but the surrounding area had not been properly studied, he said.

Tikkala added that the coins came from areas that corresponded to present-day Germany, Sweden and Great Britain. There were also some dirhams —‬ silver coins made in the Islamic world. Dirhams previously found in Finland generally date to between about 800 and 1050, he said.

The hoard also contains several pieces of jewelry, including a silver bracelet, and "payment silver" in the form of hack silver (also called hacksilber) — pieces of silver that could be cut into smaller pieces for payments according to their weight.

The weight of the precious metal alone would make the hoard worth almost $10,000 today.

From the Viking Age, but not from Vikings

Although the hoard is from the Viking Age (traditionally, from the 793 attack on Lindisfarne until the 1066 defeat of a Viking army at Stamford Bridge in England), that doesn't mean it was buried by Vikings, Tikkala said.

"The term Viking Age does not imply that there were Vikings in Finland," he said. "We have no sources suggesting that Finland was 'Viking' in the same sense as regions of present-day Sweden, Norway, and Denmark."

Instead, Finnish historians and archaeologists had adopted the term to designate the period, he said. But the area now known as Finland was not culturally or politically part of Viking Scandinavia.

The next stage of the archaeological investigation will be to properly study the site where the two deposits were found, as well as their surroundings, Tikkala said; after that, specialists in Viking Age coins will try to identify the coins and prepare a detailed report.

"There will definitely be scientific articles published on the hoard as a whole, as well as more detailed studies of the coins themselves," he said.

Until now, Finland's largest Viking Age hoard was found in 1895. Buried at Nousiainen, about 130 miles (210 km) southwest of Sysmä, it contained more than 1,700 silver coins but weighed only about half as much as the newfound hoard.

Other Nordic countries have also recently reported their largest Viking Age hoards. A cache of more than 4,700 coins was found in Norway this past spring, and a homeowner in Denmark unexpectedly discovered a hoard of more than 700 silver objects weighing more than 40 pounds (18.5 kg) in their backyard, also in the spring.

See how much you know about ancient norsemen with our Viking quiz!

The world's oldest known habitual drug use can be traced to an island in Indonesia, where ice age hunter-gatherers sucked on betel nuts — palm seeds that contain a neuroactive substance, a new study finds.

Scientists made the discovery after studying strange grooves in the teeth of two prehistoric hunter-gatherers. The deep grooves were caused by regularly sucking on betel nuts (Areca catechu), likely for relief from the pain of toothache, according to the study, which was published Wednesday (Sept. 9) in the journal Science Advances.

The partial skeletons of the two people were found on the island of Sulawesi, but their lives were separated in time by thousands of years. One of them, a man who died between about the ages of 40 and 50, lived between 25,000 and 16,000 years ago. This period roughly corresponds to the Last Glacial Maximum, the coldest part of the last ice age — although Sulawesi was not covered with ice at that time. The second person, who was around the same age when they died, lived on Sulawesi between 7,600 and 6,300 years ago, according to the study. The sex of this individual could not be determined.

Betel nuts contain a neuroactive compound called arecoline, which has a powerful stimulant effect when chewed with slaked lime, or calcium hydroxide. This early method of directly sucking betel nuts, however, would have only made the mouth numb.

These hunter-gatherers had so much dental damage, the new analysis found that they must have sucked on betel nuts almost continuously throughout their lives. But it seems these numbing nuts didn't have the desired effect in the long run. Instead, it may have made their dental conditions worse by eventually exacerbating any painful holes in their teeth.

"The more they sucked on the nut to relieve toothache, the worse that the damage to their teeth became," study first author Adam Brumm, an archaeologist at Griffith University in Australia, told Live Science. The grooves progressively became deeper, and in one individual they exposed the tooth's inner pulp cavity. "It would have been excruciatingly painful," Brumm said.

Although a 2017 study showed that Neanderthals used the bark of plants like poplar (genus Populus) for its pain-killing properties (poplars contain salicylic acid, a form of the active ingredient in aspirin), this is the earliest evidence of a drug from plants being used habitually, Brumm said.

Plant-based drugs have been used in many other prehistoric societies: 10,000-year-old traces of the pollen of a psychedelic cactus have been found in Peru, and 13,000-year-old residues of alcoholic beer have been found in Israel.

Addictive nut

After determining the likely cause of the grooves, the researchers tested whether sucking on betel nuts — a behavior not seen before — resulted in a neuroactive effect. Their test subjects, genetically-engineered frog eggs with human neuroreceptors, revealed there was a neuroactive effect. Then, they examined samples from the teeth, which revealed traces of betel nut use.

Betel nut, also known as areca nut, is still widely used today in parts of South Asia and Oceania. Today, however, betel nut users mix it with slaked lime to make a chewable wad that has a stimulant effect. This chewable wad, also called a quid, is strongly addictive, and is used by an estimated 600 million people worldwide. But arecoline is also carcinogenic, and betel nut quids are often mixed with tobacco, so users are often diagnosed with mouth cancer.

The researchers speculate that the use of slaked lime with betel nuts originated much later, during the Neolithic, or "New Stone" Age, about 4,000 years ago on Sulawesi, when slaked lime was added to pottery to prevent it from shrinking and cracking during firing.

"It now seems probable that betel chewing as we know it evolved from a much simpler, older practice of just sucking on the intact nut," the researchers wrote in the new study.

It's likely that people of all ages used this remedy for toothache in prehistoric times, but the grooves only became apparent in mature people who had become addicted to the practice, Brumm said.

Drug use started before farming

The earlier betel-sucking man predated the Neolithic period not only in Sulawesi but also in the Fertile Crescent, where people began practicing agriculture around 12,500 years ago, Brumm said. Archaeologists have long debated whether people began using neuroactive plants as drugs before or after the introduction of farming, but the new finding shows that psychoactive drug use happened thousands of years earlier, Brumm said.

The new study is a "fantastic piece of research," Elisa Guerra Doce, a prehistoric archaeologist at the University of Valladolid in Spain who was not involved, told Live Science in an email.

The new study gives "particularly compelling and direct evidence for the antiquity of drug use," she said.

Guerra Doce is an expert on the prehistoric use of plants as neuroactive drugs. "In the specific case of betel nuts, the findings are especially significant because they also reveal the prehistoric roots of a deeply established cultural practice in Southeast Asia and the Pacific," she said.

The study also highlights how the prehistoric people of Sulawesi explored their natural world and figured out that it not only provided subsistence and medicinal resources but also had "substances that became integrated into social and cultural traditions over thousands of years," Guerra Doce said.

A man searching for spare auto parts at a junkyard in Poland discovered an entirely different kind of treasure: part of a 1,800-year-old shield that was filled with bones.

The shield's age and location suggest that it belonged to a Vandal warrior, according to the archaeologists who excavated the find. The Vandals were Germanic people who lived in Poland at that time. After the Germanic invasions of the Roman Empire, the Vandals, whose name became synonymous with destruction, moved south and eventually settled in North Africa in A.D. 429, long after this shield was buried.

The bones seem to have been part of a cremation, which was also a Vandal tradition. However, the archaeologists lamented in an Aug. 20 Facebook post that the original grave has been lost to time.

The newfound artifact consists of the shield's central iron "boss," or "umbo," which protected the hand while supporting the wood and leather of the full shield built around it. The wood and leather have now rotted away.

The shields of Roman legionaries also had a central boss. But the Romans never got that far north, and the pointed style of the boss indicates it is of second-century Vandal origin.

Junkyard find

According to the Facebook post, the shield boss was discovered earlier this month at a junkyard in the town of Hrubieszów, near Poland's southeastern border with Ukraine.

The man who found it immediately knew the artifact was very old, and he sent a photograph of it to the Father Stanisław Staszic Museum at Hrubieszów. Archaeologists there verified its likely origin, and the cremated bones were found during later examinations of a plug of dried earth inside the boss.

"The state of preservation of the umbo, especially its characteristic surface, indicates that it was exposed to high temperatures," museum representatives stated in the post. "This fact, combined with the burnt bones inside, clearly indicates the cremation burial of a warrior from the Vandal community." The Vandals are associated with the Przeworsk culture in Poland, after the town where evidence of them was first found.

"Unfortunately, we will probably never know what else was found in this destroyed burial ‪—‬ perhaps a sword, spearheads, javelins, a belt buckle, or a cloak clasp," the museum team noted.

See if you know what these mysterious artifacts are with our archaeological fragments quiz!