Meteorite dates lunar volcanoes

Volcanoes were active on the Moon's surface soon after it was formed, a new study in the journal Nature suggests. Precision dating of a lunar rock that fell to Earth shows our satellite must have had lava erupting across its vast plains 4.35 billion years ago. This is hundreds of millions of years earlier than had been indicated by the rocks collected by Apollo astronauts. Scientists say the information will help us better understand the beginnings of the Solar System. And they urge future Moon missions to try to obtain more of these most ancient rocks. "We want to understand how the Solar System formed, how the planets formed," said Mahesh Anand from the UK's Open University. "The Moon is the only place where you can go to find the first 500 million years of geological history, because these old rocks have been lost on Earth," he told BBC News. Botswana fortune: According to the favoured theory, the Moon was created some 4.5 billion years ago in a smash-up between the Earth and a Mars-sized body. Material thrown into space is believed to have coalesced to become our satellite. Kalahari 009 is the biggest of all the known lunar meteorites Volcanism on this new object would not have started until its surface had cooled to form a crust and its insides had become separated into a mantle and a core. Quite when this might have happened has been hard to pin down. Virtually none of the basaltic rocks collected by moonwalkers are older than 3.

9 billion years; but with less than 400kg of lunar material returned to Earth, many scientists suspected Apollo would not be the last word on the subject. Now, Dr Anand - working with Dr Kentaro Terada, from Hiroshima University, Japan, and other colleagues - has put a new date on a lunar meteorite known as Kalahari 009. Sometime in the past, this 13.5kg volcanic rock was blasted off the Moon by the impact of an asteroid or comet and fell to Earth in what is now Botswana.

Lost lands, forgotten realms

Atlantis! Lemuria! Shamballha! Shangri-La! The very names conjure up images of sunken cities or forgotten lands hidden in the impenetrable jungle or amongst mountain peaks somewhere beyond the edges of civilization. They also suggest ancient and powerful cultures and technologies long vanished from the world, remnants of which—if popular imagination is to be believed—may still lie slumbering in the caverns far beneath the earth. Is there any truth in such beliefs? Allied to the names of these ancient places are further stories of legendary sites—places like the Garden of Eden in Christian lore, Ygdrassil, the World-Tree of Viking myth or even Davy Jones’ Locker, recently made famous by the film series Pirates of the Caribbean.

So strong has the lure of these distant, exotic and often fabulous places proven to be that many men have gone in search of them, either as individuals or at the head of expeditions, some of which have been provided by their own countries. A good number have set out to find wealth or land, some have done so for political reasons, and a few for the sheer adventure of the enterprise. Some have returned empty-handed, a number have perished in the attempt, and some have simply vanished, thus fuelling speculation that there might be some truth in such legends.

But it was not only lost explorers who fuelled the popular idea of distant realms. Television and film makers took up the challenge of actually creating these worlds and giving them some sort of immediacy. Popular films on the big screen such as The Lost World, Journey to the Centre of the Earth and even the more recent remake of King Kong, set on a forgotten island where a giant gorilla dwells, have speculated about what sort of environments these places might have. Were they, for example, swarming with prehistoric creatures or homes to advanced cultures that might fight to guard their privacy or be preparing to attack us in our own locations? Indeed the idea of some monstrous race, lurking in the depths far beneath us and armed with futuristic weapons is a common thought which has barely diminished and still stays in the public nightmares, even today. On the other hand, the possibility of a place of monastic tranquillity, shut away from a turbulent world, was also encapsulated in Frank Capra’s 1937 film Lost Horizon, sparking a popular belief that perhaps such a place might well exist tucked away somewhere in the high Eastern mountains. Such a suggestion may still remain, for although orbiting satellites have mapped most of our world for us, there is still a suggestion that in some remote region there is still someone or something—some race of men or creatures—which remains undetected and may either aid or else turn upon mankind at a future date. The possibilities of lost worlds seem endless.

Lost lands have also provided inspiration for some well known writers and appear in many works of literature from Edward Bulwer-Lytton’s 1870 masterpiece The Coming Race to Jack Vance’s 1980s Lyonesse trilogy. Such books have kept these places in the public eye and have stirred the imaginations of countless readers. But why has interest in them remained so strong throughout the years? Why, for example, has the Atlantis story achieved such a hold on popular thought? And why has Shangri-La stayed at the foremost of our minds, becoming almost a cliché?

For some they represent, for example, no more than our deepest hopes and desires for an ideal state of being. They may, as they did for Adolph Hitler and the Nazi Party of Germany, symbolize the home of some form of idealized beings or men whose wisdom is far beyond that of the mundane world. Or they may, as they did for Madam Blavatsky, suggest the original cradle of mysticism which surrounds our existence. They may even represent some idealized state towards which mankind can strive.

And, of course, they also stand for worlds of wonder. The idea of a kingdom such as Lyonesse, drowned forever beneath the freezing waters of the ocean through the petulant whim of a spoiled daughter; of a nightmarish city like Irem, raised in the desert by unseen demonic forces; of the lost land of Bimini where gushing water confers eternal youth on all those who drink from a wonderful fountain there, all excite and entice us. The vision of the lost golden city of El Dorado, hidden deep in the South American jungle or the less material treasure of contentment to be found in the mystical monastic city of Shangri-La somewhere amongst the towering Himalayan peaks, lures something in all of us. In earlier times, those destinations were a goal that might be attained through adventure and daring. In many ways, they also represented the last great challenge of Mankind.

As travel and new communications cause our perceptions of the world to shrink and become more routinely predictable, these places represent the last wild and unknown locations and may still offer a chance for exploration, excitement and danger. Because of this, the idea of lost lands, vanished places and long-disappeared civilizations will not go away.

Mystery mechanism heals high-tech composite

Self-healing composite materials that can fix small cracks in the structures of planes, bridges, and wind turbines could become more cost-effective thanks to a new bonding mechanism discovered by researchers in the US. Engineers have high hopes for composite materials that can repair small cracks in their structure. "When you have any damage induced by fatigue, there's usually nothing you can do except wait for catastrophic failure," says Jeffrey Moore, who led the research at the University of , Urbana, US. Self-healing composites should change that. These materials contain capsules of a liquid adhesive which leaks out and repairs tiny cracks when they appear. However, the adhesives usually require some kind of post-processing to make them set, such as curing with UV light or heating to high temperatures. What engineers would prefer, though, is a material that healed itself without any extra intervention. Rare catalyst: In 2001, Moore's group developed just such a material that relied on the mixing of two different chemicals that set like a two-part epoxy. The material contains two types of capsule: one containing a ring hydrocarbon called dicyclopentadiene and the other containing a ruthenium solvent that acts as a catalyst, causing the rings to break open and polymerise. Any crack causes the chemicals to mix and set, bonding the crack faces together. But ruthenium is rare. "An Airbus fuselage has 60,000 pounds of composites in it.

If you used the catalyst approach, a significant fraction of the world supply of ruthenium would be flying around in one plane," Moore told New Scientist. That makes it impractical for most applications, so his team set to work looking for an alternative. Seeking to improve the approach, the group changed to a nickel-based catalyst, but had to change the solvent as well. The first step was to gauge the new solvent in the absence of a catalyst.

Ghost hunters uncover old murder

A team of paranormal investigators from Lancashire got more than they bargained for on their second visit to an Inn in Leyland. During the investigation the team undertook an experiment where they asked the spirits to move a table.The table moved suddenly and violently, then spun around several times, nearly knocking one team member off her feet.Other strange phenomena included all of the group hearing a low pitch groan at exactly the same time, lights flickering, and unexplained sensations felt by a member of the group.Team member Andy Proctor, from Blackburn, describes events on the night of the visit as "the most amazing night of phenomena we have ever witnessed".The Ley Inn, in Chorley, is subject to many rumours of a hanging in the late 18th century.During the Ouija experiment a former Inn owner Robert O'Neil and his employee James Silcock came forward.Andy said: "Robert informed us that he once owned the land which the Ley Inn now stands on, and that he accidentally killed James Silcock, who it seems was making advances towards Robert's daughter.

"We were informed, that Robert tied up a rope and wrapped it around James' neck, in order to scare him in to leaving his daughter alone, however, these actions resulted in James' death."Whether or not these stories are connected to the original claims of the hanging which took place here, we are not sure.

The 'Bermuda triangle' started with a lost wing

In the years since his retirement as CEO of Kockums (previously Soderhamm) forestry products factory, Tom Richardson has taken up painting as a hobby. He’s pretty good, too. He even won first prize at an arts fair in Florida, best of show out of about 300 pieces entered in the event. But another experience he had in Florida crosses his mind from time to time — a post-World War II tragedy that has inspired books, television programs, movies and a catalog of unexplained phenomena theories that have found a place in the national lexicon under the “Bermuda Triangle” heading. On Dec. 5, 1945, Richardson was assigned the role of duty officer at the Fort Lauderdale Naval Air Station, where that assignment fell to him once or twice a year. And in that capacity, he became a witness to a tragedy that has become legend. It was one of his last duties in the Navy. With the war over, he had less than a month remaining in the service. He spent the rest of his days in the Navy flying missions in a massive and fruitless search for any sign of the lost aircraft and airmen. Just months after the Japanese surrender and the end of the war, Lt. Charles Taylor led a formation of five Grumman Torpedo Bombers with a combined crew of 14 on a routine training mission and disappeared without a trace. Less than an hour after their disappearance, a rescue plane sent out to try to find them exploded 13 minutes after takeoff, killing 13 more men.

An aeronautical engineering student when the war began, Richardson had enlisted with a desire to be a Navy combat pilot. As most of his class of pilots was being sent to the Pacific, Richardson was sent for additional instrument training. Instead of being sent into combat, he was assigned as a flight trainer to prepare other pilots for war.

Prehistoric sea "monster" discovered

Remains of a bus-sized prehistoric "monster" reptile found on a remote Arctic island may be a new species never before recorded by science, researchers said Tuesday. Initial excavation of a site on the Svalbard islands in August yielded the remains, teeth, skull fragments and vertebrae of a reptile estimated to measure nearly 40 feet long, said Joern Harald Hurum of the University of Oslo. "It seems the monster is a new species," he told The Associated Press. The reptile appears be the same species as another sea predator whose remains were found nearby on Svalbard last year. His team described those 150-million-year-old remains as belonging to a short-necked plesiosaur measuring more than 30 feet — "as long as a bus ... with teeth larger than cucumbers." The short-necked plesiosaur was a voracious reptile often compared to the Tyrannosaurus rex of the oceans.

Mark Evans, a plesiosaur expert at the Leicester City Museums in Britain, said he not know enough about the Norwegian find to comment on it specifically. But he said new types of the sea reptiles are being found regularly.

Lost lands aplenty

The lost island of Atlantis continues to fascinate mankind. It harks back to a Golden Age when things were different. But of course, it couldn't last. Not if it involved man. So man caused the gods to destroy his paradise. It is a typical story -in one way it echoes our lives, in that when we've got it good, we tend to upset things, as if we're a self-destructive species. However, Atlantis is not the only supposed lost land from the past. Lyonesse: Many western cultures have myths of lost lands, where once lived our great ancestors. Typical is Lyonesse, a fabled land once said to exist between Land's End and the Scilly Isles, off the British coast. On this land stood the city of Lions and some 140 churches. Folk tales, and later poets such as Tennyson, kept the fable alive by associating it with King Arthur. Thought to be the place of his birth, his death has also been associated with the lost land. Logically, it seems the fable arose from its association with the Breton town St-Pol-de-Leon, know to the Roman's as Leo's Castle. Atland: Another such fable concerns Atland. First coming to popular attention in 1848, when antiquarian Cornelius Over de Linden first produced his Pera Linda Book, Atland is said to be an ancient land off the Dutch Frisian coast. With a sub-tropical climate and well advanced, happy population, a catastrophe struck in 2l93BC, destroying the land. Survivors went on to travel the world, founding Egyptian, Greek and Indian civilisations. The Oera Linda Book was written on cotton paper and de Linden claimed it came from 1256, copied from an even older work.

Published in 1876, many people consider it a fraud. Lemuria: Some lost lands are more modern, and said to be rationally theorised to have existed. For instance, there is a problem with a primitive group of primates called lemurs. They are found only on Madagascar, off the African coast. But they have close relatives in the bushbabies of Africa and the lorises of India. Prior to the understanding of continental drift, zoologists realised this was mysterious.

The strange lives of polar dinosaurs

On a balmy Sunday morning in early March, I'm on a beach in southern Australia looking for ice—or at least traces of it. It's summer in the Southern Hemisphere, and most of the beachgoers sloshing through the rising tide or walking their dogs are wearing T-shirts and shorts. Tom Rich, a paleontologist at Museum Victoria in Melbourne, leads the way along the low, tawny cliffs that crowd the shoreline. Rich is 66, with a stubbly silver beard, sparse gray hair and slanting eyebrows that give his face a sad, world-weary look. He was raised in Southern California and Texas but has spent his professional life in Australia. During more than three decades down under, he's picked up Aussie citizenship and plenty of the country's colorful lingo, but his accent remains stubbornly American. "I sound like I just got off the plane," he says. This part of the coast, known as Flat Rocks, is near the resort town of Inverloch, about a two-hour drive southeast of Melbourne through farms and woodland parched by more than a decade of drought. Rich stops next to a pile of rubble at the base of a cliff. "That's it," he says. Partly buried by flakes of battleship-gray rock is a telling geological formation. Tongues of dark tan sediment droop into the lighter-colored layer below. The formation is called a "cryoturbation" and was caused when once-frozen clay sank into an underlying layer of sand during a thaw long ago. Snow and ice are rare in this part of Australia today.

But evidence from Flat Rocks and other nearby sites confirms that a little over 100 million years ago, "it was bloody cold around here," as Rich puts it. Though about a third of Australia now lies within the tropics, back then the continent sat about 2,000 miles south of its current position, snuggled against Antarctica. Southeastern Australia probably had a climate similar to that of Chicago, if not Fairbanks. All the more surprising, then, that dinosaurs thrived here at that time.

Mystery lights spotted over Teignmouth

Spooky lights spotted over Teignmouth have freaked out some locals. There were dozens of reports about the strange, whitish-coloured shapes moving up and down the estuary early on Monday evening.Was it extra terrestrials, or did the objects in the sky have a simpler, down-to-earth explanation such as lasers? So far it remains a mystery, but one woman who witnessed the display from her window high up on a hill, told the Herald Express: "It was beautiful, and a little scary at the same time. "The white lights changes shaped, moved very fast and would suddenly disappear, only to return a few minutes later. "I don't believe in UFOs or flying saucers, but this was very strange, and made me feel a little bit uneasy. "I am sure there is a perfectly logical reason behind it, and I hope somebody will be able to explain it all." Well-known Teignmouth councillor Fred Tooley was among the many residents who witnessed the display between about 6pm and 7pm. He said: "There were patterns of white lights, like blobs, but changing shape, that swept up and down the river between the Ness and Shaldon Bridge. "I was mesmerised, and lots of other people have told me they saw it all as well. "I don't think the shapes were that high in the sky, and they appeared to be bouncing off low cloud over the estuary.

"To me it resembled the flocks of starlings that swoop around in huge numbers, making patterns at roosting time. "But this was definitely not birds, and it was really weird. Your imagination does run riot when you see something like this, and I hope your readers can tell me what it was. "Hopefully it wasn't the prelude to an invasion of Teignmouth by ETs," Cllr Tooley quipped.

Chimps outperform humans at memory task

Young chimps can beat adult humans in a task involving remembering numbers, reveals a new study. It is the first time chimps – and young ones, at that – have outperformed humans at a cognitive task. And the finding may add weight to a theory about the evolution of language in humans, say the researchers. Three adult female chimps, their three 5-year-old offspring, and university student volunteers were tested on their ability to memorise the numbers 1 to 9 appearing at random locations on a touchscreen monitor. The chimps had previously been taught the ascending order of the numbers. Using an ability akin to photographic memory, the young chimps were able to memorise the location of the numerals with better accuracy than humans performing the same task. During the test, the numerals appeared on the screen for 650, 430 or 210 milliseconds, and were then replaced by blank white squares. Photographic memory: While the adult chimps were able to remember the location of the numbers in the correct order with the same or worse ability as the humans, the three adolescent chimps outperformed the humans. The youngsters easily remembered the locations, even at the shortest duration, which does not leave enough time for the eye to move and scan the screen. This suggests that they use a kind of eidetic or photographic memory. In rare cases, human children have a kind of photographic memory like that shown by the young chimps, but it disappears with age, says Tetsuro Matsuzawa, at the primate research institute at Kyoto University, Japan, who led the study. He suggests that early humans lost the skill as we acquired other memory-related skills such as representation and hierarchical organisation.

“In the course of evolution we humans lost it, but acquired a new skill of symbolisation – in other words, language,” he says. “We had to lose some function to get a new function.” 'Humbling' discovery: The finding challenges human assumptions about our uniqueness, and should make us think harder about ourselves in relation to other animals, says anthropologist Jill Pruetz of Iowa State University, Ames, US. “Observing that other species can outperform us on tasks that we assume we excel at is a bit humbling,” she says.

Algae emerges as a potential fuel source

The 16 big flasks of bubbling bright green liquids in Roger Ruan’s laboratory at the University of Minnesota are part of a new boom in renewable energy research. Driven by renewed investment as oil prices push $100 a barrel, Dr. Ruan and scores of scientists around the world are racing to turn algae into a commercially viable energy source.Some algae is as much as 50 percent oil that can be converted into biodiesel or jet fuel. The biggest challenge is cutting the cost of production, which by one Defense Department estimate is running more than $20 a gallon.“If you can get algae oils down below $2 a gallon, then you’ll be where you need to be,” said Jennifer Holmgren, director of the renewable fuels unit of UOP, an energy subsidiary of Honeywell International. “And there’s a lot of people who think you can.” Researchers are trying to figure out how to grow enough of the right strains of algae and how to extract the oil most efficiently. Over the past two years they have received more money from governments, the Pentagon, big oil companies, utilities and venture capital firms.The federal government halted its main algae research program nearly a decade ago, but technology has advanced and oil prices have climbed since then, and an Energy Department laboratory announced in late October that it was partnering with Chevron, the second-largest American oil company, in the hunt for better strains of algae.“It’s not backyard inventors at this point at all,” said George Douglas, a spokesman for the National Renewable Energy Laboratory, an arm of the Energy Department.

“It’s folks with experience to move it forward.”A New Zealand company demonstrated a Range Rover powered by an algae biodiesel blend last year, but experts say algae will not be commercially viable for many years. Dr. Ruan said demonstration plants could be built within a few years.Converting algae oil into biodiesel uses the same process that turns vegetable oils into biodiesel.

Scientists get rare look at dinosaur soft tissue

A high school student hunting fossils in the badlands of his native North Dakota discovered an extremely rare mummified dinosaur that includes not just bones but also seldom seen fossilized soft tissue such as skin and muscles, scientists will announce today. The 25-foot-long hadrosaur found by Tyler Lyson in an ancient river flood plain in the dinosaur-rich Hell Creek Formation is apparently the most complete and best preserved of the half-dozen mummified dinosaurs unearthed since early in the last century, they said. Much scientific investigation remains to be done, and no peer-reviewed studies of it have yet been published, but the discovery appears to be yielding tantalizing new clues about the size, body mechanics and appearance of the reptilian beasts that ruled the Earth millions of years ago, said paleontologists studying the specimen. "He looks like a blow-up dinosaur in some parts," said Phillip Manning, a paleontologist at the University of Manchester in England who is leading the inquiry. "When you actually look at the detail of the skin, the scales themselves are three dimensional. . . . The arm is breathtaking. It's a three-dimensional arm, you can shake the dinosaur by the hand.

It just defies logic that such a remarkable specimen could preserve." Although it is described as "mummified," the 65 million-year-old duckbilled dinosaur that scientists have named Dakota bears no similarity to the leather-skinned human mummies retrieved from ancient tombs in Egypt. Time long ago transformed Dakota's soft tissue into mineralized rock, preserving it for the ages.

Skin ageing 'reversed' in mice

Scientists have reversed the effects of ageing on the skin of mice by blocking the action of a specific protein. In two-year old mice, Californian researchers found that they could rejuvenate skin to look more youthful. Further analysis published in the journal Genes and Development showed the skin had the same genetic profile as the skin of newborn mice. The team said the research would most likely lead to treatments to improve healing in older human patients. They stressed it was unlikely to be a potential "fountain of youth" but could help older people heal as quickly from injury as they did when they were younger. The protein in question - NF-kappa-B - is thought to play a role in numerous aspects of ageing. It acts as a regulator, causing a wide range of other genes to be more or less active. Lead researcher, Dr Howard Chang, from the Stanford School of Medicine in California, said the findings supported the theory that ageing is the result of specific genetic changes rather than accumulated wear and tear. And that it is possible to reverse those genetic changes later in life. Regulation: Previous studies have identified several genes which play a part in the ageing process. Dr Chang and colleagues spotted that the one thing the genes had in common was that they were regulated by NF-kappa-B, which can either make them more or less active. By blocking the protein in older mice for two weeks, they found the skin was thicker and more cells appeared to be dividing, much like the skin of a younger mouse.

And the same genes were active as in the skin of newborn mice. It is unclear whether the effects are long-lasting and the protein has also been implicated in cancer and regulation of the immune system. "We found a pretty striking reversal to that of the young skin," Dr Chang said. But he added any application in humans was likely to be on a short-term basis because of other effects of blocking the protein.

Dinosaur graveyard and a new extinction theory

Spanish scientists have unearthed what could be Europe's largest dinosaur boneyard, finding the remains of 65ft plant-eaters never before discovered on the continent. The palaeontologists believe they have found eight different species amid the 8,000 fossils discovered so far. The range of species they are finding at the 80 million-year-old site and their state of conservation is virtually unparalleled in Europe and challenges long-held beliefs about the way in which dinosaurs became extinct. "This is completely beyond what we expected to find," Francisco Ortega, co-director of the excavation, told The Times. "This represents a huge leap in our understanding of the Upper Cretaceous (period)." Dozens of experts are working around the clock to excavate the site. It was discovered in June during construction work for a new high-speed rail link between Madrid and Valencia. Palaeontologists, who kept the discovery under wraps, have until the end of the month to remove the skeletons of several hundred dinosaurs before the diggers move back in. Researchers have not finished excavating the entire area of Lo Hueco, near the city of Cuenca, in western Spain. But they say they have retrieved most of the fossils from the path of the railway. The find is from a period palaeontologists have little information on in Europe. Most of the sites dating from that period have been found in the Americas. Scientists had long believed that the diversity of dinosaurs declined sharply as they approached the end of their time on earth.

Palaeontologists working in Lo Hueco, though, have been amazed to find a wide variety of dinosaurs from the period. "Everything indicates that the dino-sours were enjoying great evolutionary vigour when they suddenly disappeared," said José Luis Sanz, the co-director of the dig. Mr Ortega said the find should help shed light on the extinction of the dinosaurs in Europe and whether they also died out as a result of the huge meteorite that struck modern-day Mexico.

'Yeti prints' found near Everest

A US TV presenter says he and his team have found a series of footprints in the Everest region of Nepal resembling descriptions of the mysterious Yeti. The presenter and his colleagues say they are "very excited", although they are not saying they definitely believe it is the mark of the Yeti. Josh Gates and his crew work on a series called Destination Truth, which follows reports of fantastic creatures. The footprints found on Wednesday have renewed Yeti excitement in Nepal. Mr Gates said they had been searching by torchlight at night-time because, he said, alleged sightings of the yeti had usually taken place at night. They did not see the so-called abominable snowman himself. Three prints: But a Nepalese member of the team spotted three footprints and alerted Mr Gates, who told the BBC the first print was a "pristine" right paw mark, 33 cm (13 inches) long, with five toes in a wide spread of 25 cm. There was also a heel print and another fainter one. An excited Mr Gates described the main footprint as anthropomorphic, meaning it had human characteristics. He said he did not believe the prints were man-made or that they came from a known animal such as a bear. But he also said he was not sure he believed in the Yeti, and did not know what to make of it. The team took castings of the three prints which will be examined by scientists in the US. Scalp claim: Asked why there were only three prints, Mr Gates said the terrain, in a side valley about 2,800 metres (9,000 feet), was mainly rocky.

Reports of the mythical Yeti go back hundreds of years, and the creature is sometimes attributed with dangerous powers, sometimes protective ones. One Buddhist monastery near Everest houses what some say is a Yeti skull or scalp; scientists who examined it declared that it was made from antelope skin, but other experts disagreed. In the 1950s the British explorer Eric Shipton took photos of prints in the snow that some are convinced belong to the Yeti.

Israeli says elusive biblical wall found

A wall mentioned in the Bible's Book of Nehemiah and long sought by archaeologists apparently has been found, an Israeli archaeologist says. A team of archaeologists discovered the wall in Jerusalem's ancient City of David during a rescue attempt on a tower that was in danger of collapse, said Eilat Mazar, head of the Institute of Archaeology at the Shalem Center, a Jerusalem-based research and educational institute, and leader of the dig. Artifacts including pottery shards and arrowheads found under the tower suggested that both the tower and the nearby wall are from the 5th century B.C., the time of Nehemiah, Mazar said this week. Scholars previously thought the wall dated to the Hasmonean period from about 142 B.C. to 37 B.C. The findings suggest that the structure was actually part of the same city wall the Bible says Nehemiah rebuilt, Mazar said. The Book of Nehemiah gives a detailed description of construction of the walls, destroyed earlier by the Babylonians. "We were amazed," she said, noting that the discovery was made at a time when many scholars argued that the wall did not exist. "This was a great surprise. It was something we didn't plan," Mazar said. The first phase of the dig, completed in 2005, uncovered what Mazar believes to be the remains of King David's palace, built by King Hiram of Tyre, and also mentioned in the Bible. Ephraim Stern, professor emeritus of archaeology at Hebrew University and chairman of the state of Israel archaeological council, offered support for Mazar's claim. "The material she showed me is from the Persian period," the period of Nehemiah, he said.

"I can sign on the date of the material she found." However, another scholar disputed the significance of the discovery. Israel Finkelstein, professor of archaeology at Tel Aviv University, called the discovery "an interesting find," but said the pottery and other artifacts do not indicate that the wall was built in the time of Nehemiah. Because the debris was not connected to a floor or other structural part of the wall, the wall could have been built later, Finkelstein said.