Dinosaur tracks reconstructed

Twelve years ago, footprints of carnivorous dinosaurs were discovered and excavated in a quarry near Goslar. Paleontologists from the University of Bonn, working with Dinosaur Park Münchehagen and the State Museum of Hanover, have now created a three-dimensional digital model based on photographs of the excavation. The reconstruction of the discovery site suggests that carnivorous dinosaurs hunted herbivorous island-dwelling dinosaurs about 154 million years ago. They believe the predators could have immigrated via a land bridge as sea levels dropped.

The findings have now been published in the geoscience journal Palaeontologia Electronica.

In 2003, a private fossil collector made a surprising discovery in a limestone quarry near Goslar in Lower Saxony: a total of 20 dinosaur footprints imprinted on a stone slab. Nils Knötschke, from Dinosaur Park Münchehagen, was able to salvage five of the tracks and kept them from being destroyed by the quarry work. Now, about a dozen years later, paleontologists from the University of Bonn, led by Prof. Dr. Martin Sander, have worked with Nils Knötschke and Dr. Oliver Wings from the State Museum of Hanover to reconstruct the tracks in a three-dimensional model, using digital methods. The project was based on photos of the tracks taken at the time when they were excavated.

"Even five years ago, it wouldn't have been technically possible to do this kind of reconstruction," says first author Jens N. Lallensack of the Steinmann Institute for Geology, Mineralogy and Paleontology at the University of Bonn. Based on the 3D model, the researchers were able to gain crucial information about the dinosaurs that left the footprints behind, and about their habitat at the time. The tracks, measuring between 36 and 47 centimeters in length, probably represent two different species of predatory dinosaurs from the Theropoda group.

Glimpses of the habitat 154 million years ago

Based on the digital model, we can now see how the individual footprints are positioned in relation to one another. "That allowed us to reconstruct the moving direction, and how fast the animals were traveling. Based on the length of the footprints, we can estimate that the largest animals had a body length of about eight meters. In some places, the carnivorous dinosaurs also left much deeper tracks in the sediment than elsewhere. "Where the ground was soft, the dinosaurs sank in much deeper than where it was dry," reports Lallensack.

About 154 million years ago, during the Late Jurassic Era, there was a shallow sea throughout this region, with small islands jutting up out of it. Bones found in the Langenberg Quarry confirm that the islands were inhabited by a species of small dinosaurs, Europasaurus holgeri. These herbivores belonged to the group of gigantic, long-necked dinosaurs called sauropods. However, a full-grown Europasaurus only measured six to eight meters -- about one-fourth the length of its nearest relative, Camarasaurus. "The dinosaur probably had to shrink down to dwarf size in order to survive, given the limited food available on these small islands in the shallow Central European sea," says Lallensack.

Theropods probably immigrated via a land bridge

The theropods that originally made the reconstructed dinosaur tracks came on the scene about 35,000 years later. "It's possible that the sea level dropped during this period -- a relatively short time from a geological perspective -- and that the mainland carnivorous dinosaurs immigrated at that point," surmises Dr. Wings, who is heading a research project funded by VolkswagenStiftung at the State Museum of Hanover on the overall Jurassic habitats of the region. The theropod tracks come from a dried-up ocean floor bed very close to one of the islands.

Read more at Science Daily

Sun Storm Supercharges Northern Lights

Brilliant streaks of green, purple and pink lit up skies across Canada and many northern U.S. states on Monday night, in brilliant auroral displays following a massive solar storm.

The auroras were seen as far south as Philadelphia and northern New Jersey last night (June 22), and gave astronauts aboard the International Space Station a stunning celestial light show. The solar storm that caused the auroras was declared a level G4 (severe), with a maximum possible ranking of G5 (extreme).

Auroras, also known as the northern and southern lights, are caused by bursts of powerful particles ejected from the sun that collide with Earth’s atmosphere. The solar storm behind last night’s spectacular light display continues to rage, and officials say auroras should be visible again tonight (June 23) for viewers in Canada and parts of the U.S.

Photographer Jeff Berkes snapped photos of the rippling northern lights over a field in southern Philadelphia. In an email to Space.com, Berkes said these were the most intense northern lights he has ever seen in this location.

Meteorologist Eric Holthaus wrote in an article for Slate that the coronal mass ejection had picked up two smaller, slower ejections from last week, building in power as the particles raced toward Earth. Once there, they whipped up a geomagnetic storm as the Earth’s magnetic field adjusted to the new addition — and the results could be seen all across the northern United States and Canada.

The solar storm erupted from the sun during the day on Sunday (June 21). As the sun belched out a fiery solar flare, it also released a huge coronal mass ejection — a stream of charged particles. The size and strength of this particular particle ejection were dubbed “impressive” by scientists working on NASA’s Advanced Composition Explorer mission as the storm shot by the ACE spacecraft on the way to Earth Sunday afternoon.

A solar storm lit up the night sky above Mammoth Hot Springs last night. #AuroraBorealis #NorthernLights pic.twitter.com/s9x79docjv — YellowstoneNPS (@YellowstoneNPS) June 23, 2015

The storm reached severe levels as of 1:13 a.m. EDT (0513 GMT) today, according to the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center, and fast solar wind conditions and strong magnetic fields will likely continue — meaning auroras will likely be visible again tonight for lucky skywatchers.

Read more at Discovery News

Dawn Mission Reveals More Detail in Mysterious Ceres

From its orbital perch 2,700 miles above Ceres, NASA’s Dawn spacecraft returned new images of the dwarf planet showing more even more small bright spots inside a 55-mile crater.

At least eight bright areas now have been found next to a large white region glinting inside the crater. Scientists suspect they are seeing some kind of highly reflective material, such as ice or salt, but there are other options as well, like geysers, volcanoes or rock.

The new images, which were taken on June 9 and released today (June 22), also show that Ceres has a steep, three-mile high mountain rising from the surface in an area that is otherwise relatively smooth and flat.

Several craters, many with central peaks, have been discovered, along with landslides, flows and collapsed structures that are evidence of past surface activity.

In August, Dawn is scheduled to make more observations of Ceres from a lower orbit just 900 miles above the surface.

From Discovery News

Ancient Greeks Were Afraid of Zombies

The ancient Greeks believed in ghostly versions of the dead who would rise from their graves and stalk the living, according to deviant burials unearthed in the necropolis of a Greek colony in Sicily.

Known as Passo Marinaro, the cemetery near the coastal town of Kamarina in southeastern Sicily, was in use from the 5th through 3rd centuries B.C. The necropolis has yielded approximately 2,905 burials; more than half contained grave goods, mostly terracotta vases, but also figurines and metal coins.

Two of the tombs were unique.

One body, found in a tomb labeled 653, contained an individual of unknown sex, who apparently experienced a period of serious malnutrition or illness in life.

“What is unusual about Tomb 653 is that the head and feet of the individual are completely covered by large amphora fragments,” Carrie Sulosky Weaver, an archaeologist at the University of Pittsburgh, wrote in Popular Archaeology.

An amphora is a large, two handled ceramic vessel that was generally used for storing wine and olive oil.

“The heavy amphora fragments found in Tomb 653 were presumably intended to pin the individual to the grave and prevent it from seeing or rising,” Sulosky Weaver said.

The other burial, labelled 693, contained the remains of a child of indeterminate sex about 8 to 13 years old. No signs of diseases were found on the remains, nevertheless the child was buried with five large stones placed on top of the body.

“It appears that these stones were used to trap the body in its grave,” Sulosky Weaver said.

Her research will be featured in a forthcoming book, “The Bioarchaeology of Classical Kamarina: Life and Death in Greek Sicily,” which will be published by the University Press of Florida in September.

It is unknown why the occupants of those burials were pinned in their graves, but “their special treatment suggests that necrophobic beliefs and practices were present in Greek Sicily,” Sulosky Weaver said.

“Necrophobia, or the fear of the dead, is a concept that has been present in Greek culture from the Neolithic period to the present,” she added.

Read more at Discovery News

Fetus Found Inside 17th-Century Mummified Monk's Coffin

When investigators performed a CT scan of the coffin belonging to a 74-year-old Scandinavian bishop who died almost 350 years ago, they came upon a surprise: a four- to five-month-old fetus tucked under the bishop’s feet.

The discovery was unexpected for researchers at the University hospital in Lund who hoped to learn more about the health and lives of people from that period by examining the remains of the extremely well preserved Bishop Peder Winstrup.

“You can only speculate as to whether it was one of Winstrup’s next of kin, or whether someone else took the opportunity while preparing the coffin. But we hope to be able to clarify any kinship through a DNA test,” said Per Karsten, director of the historical museum at Lund University, in a press release.

Karsten said the fetus could be related to Winstrup, who was one of the founding fathers of Sweden’s Lund University. But perhaps more likely, Karsten said, the fetus was placed there by someone with access to Winstrup’s coffin in order to have an illegitimate child buried in sanctified ground.

The preliminary results of the scan also revealed that the body still hosts most of the internal organs — unusual for a mummy.

The bishop wasn’t preserved by the usual mummification process but simply dried out naturally. The good condition of the body appears to be the result of ideal conditions — constant air flow, plant material in the coffin, a long period of illness for the bishop before death, causing him to be very lean, and the fact that he was buried during the winter months.

Analysis of the remains suggest the 74-year-old had gallstones, which could indicate a diet of fatty foods, and tooth decay possibly resulting from eating a lot of sugar. The bishop also appeared to suffer from osteoarthritis in both the knee and hip joint — and a bad shoulder.

“His right shoulder was slightly higher than his left, due to an injury to a tendon in the shoulder. This would have limited Winstrup’s mobility, making it difficult for him to carry out simple everyday tasks such as putting on a shirt or combing his hair with the comb in his right hand,” Caroline Ahlström Arcini, an osteologist working on the project, said in a press release.

Read more at Discovery News

Ancient Human With 10 Percent Neanderthal Genes Found

DNA from a man who lived 40,000 years ago in Romania reveals that up to 11 percent of his genome came from Neanderthals.

Because large segments of the individual’s chromosomes are of Neanderthal origin, a Neanderthal was among the man’s ancestors as recently as four generations back in his family tree, reports a study published in the latest issue of the journal Nature.

The finding reveals that some of the first members of our species who came to Europe interbred with the local Neanderthals.

To this day, individuals of European and Asian heritage retain Neanderthal DNA in their genomes, but whether or not Neanderthals went extinct or simply were absorbed into the modern human population remains a matter of definition, senior author Svante Pääbo told Discovery News.

“Some Neanderthals clearly became incorporated in modern human societies,” said Pääbo, director of the Department of Evolutionary Genetics at the Max Planck Institute for Evolutionary Anthropology. “It is still unclear exactly how much of the complete Neanderthal genome exists today in people, but it seems to approach something like 40 percent.”

“But, of course, the Neanderthals are clearly extinct in the sense that they do not exist as an independent, separate group since some 30,000 or 40,000 years.”

David Reich from Harvard Medical School coordinated the population genetic analysis of the study, which was an international effort. At the center of the research were the remains of the man, named “Oase 1,” unearthed at a cave system called Peștera cu Oase in Romania.

The researchers believe that the man derived from the same expansion out of Africa as other modern people, but was likely to have been part of an early “pioneer foray into Europe,” ahead of other migrations that were to come later.

Under what conditions his relatives, and those of other early Neanderthal-human hybrids, interbred is a big question.

Chris Stringer, an expert on early humans at the Natural History Museum in London, posed some intriguing questions about the matings.

“Were these peaceful exchanges of partners, raids which stole women or girls, or even the adoption of orphaned babies?” he asked, adding that the answer remains a mystery.

What is clear is that the interbreeding took place at different times and locations. This particular individual, Oase 1, did not contribute much, if at all, to later modern human populations, however. Pääbo explained that whatever population he represented seems to have “disappeared,” leaving behind no known tools or other artifacts.

The man’s DNA does share many alleles (alternative forms of genes) with present day East Asians and Native Americans.

“There are several studies now that show East Asians and Native Americans have about 20 percent more Neanderthal contribution (in their genomes) and that this could be due to extra inbreeding in the ancestors of East Asians,” Pääbo explained.

Other studies also conclude that there was likely a natural selection against a Neanderthal contribution to the Homo sapiens genome, such that even if interbreeding were very common, the evidence for that would not fully reveal itself in the genomes of modern humans of European and Asian heritage.

“In the case of the Neanderthal gene flow into modern humans, it is clear that much of that DNA has been lost or selected away since, but there are some examples where it may have been retained because it was advantageous to the modern groups receiving it,” Stringer said, adding that he was surprised that interbreeding between Neanderthals and Homo sapiens “was still happening long after 55,000 years ago.”

Read more at Discovery News

Diving on Europa? Here's How We Could Penetrate That Ice

Europa is an ice-covered moon orbiting Jupiter that likely an ocean underneath. Perhaps that ocean contains life. Perhaps it doesn’t. But we’re not going to know for sure until we send a probe there to check things out.

NASA announced last week that it’s one step closer to flying by Europa dozens of times after launching in the 2020s. The mission concept was approved and funding is ongoing. To get under that ice (virtually) NASA could include a radar instrument called REASON (Radar for Europa Assessment and Sounding: Ocean to Near-surfaces) to peer underneath. But what if we were to eventually send a robotic landing mission?

Britney Schmitt, a member of the Europa mission team, told a conference last week that her team in Antarctica is testing out the very techniques that could be used in the ice, hundreds of millions of kilometers away.

“Europa may seem alien to you and I, but if you go the Earth’s poles, it doesn’t seem as far-fetched,” said Schmidt, who is an assistant professor at the Georgia Institute of Technology’s Earth and atmospheric sciences department.

At McMurdo Station in Antarctica last year, a mini-machine called Icefin dove under the ice to check out what’s sitting underneath the shelf. That was no small feat, given that the ice is tens of meters thick. The resulting video shows what’s lurking on the seafloor. Even to Earth-accustomed eyes, it looks kind of alien.

Icefin (Schmidt is principal investigator) is powerful, but small enough that it can be carried by people. The tethered underwater vehicle even breaks down into pieces to make it easier to transport. The instruments on board are supposed to measure things such as the ice, what’s in layers of water and what’s living on the seafloor. It can dive as deep as 1,500 meters (4,921 feet) and is designed to travel at least three kilometers (1.86 miles) underwater.

And if you think that’s amazing, check out what’s swimming in the waters this summer: Artemis, a more powerful underwater vehicle that can travel up to 15 kilometers (9.3 miles). The goal is not only to test out technologies for Europa, but to better understand the fragile environment of Antarctica and how best to protect it.

Schmidt characterized the work, which is led by Georgia Tech, as key to helping with NASA’s proposed Europa mission. “Personally, I’m proud to be a part of the mission team. I’ve helped on studies for a while, and it’s just been a large group of people working for the past 20 years to get this mission going,” she said.

Read more at Discovery News

Pluto's Moons Offer Secrets and Threaten Danger

As NASA's New Horizons spacecraft zooms nearer to Pluto and its five known moons, scientists are expecting not only greatly enhanced views of the Plutonian system, but to discover more moons and perhaps unknown rings.

These discoveries could help explain what created the tiny system -- or they could destroy New Horizons before it has a chance to relay its precious data.

"The New Horizons mission provides an opportunity to reveal the compositions of the moons," said Richard Binzel, a member of the mission's science team and a planetary scientist at the Massachusetts Institute of Technology. "The compositions are the next step to decoding their origins."

Telescope studies have found that the moons vary a great deal in brightness. That suggests they are made of different mixes of materials, and so they have different origins and were possibly captured by Pluto at different times. On the other hand, their neatly arranged orbits around Pluto strongly suggest the opposite: that they formed at the same time, perhaps from an ancient collision that left Pluto orbited by Charon, the other moons and perhaps rings of debris.

The currently most accepted theory is the collision, which gives the Pluto-Charon, et al., system a lot in common with the Earth-Moon system, that is thought to have formed in the same manner when a Mars-sized body slammed into the early Earth and created our unusually large natural satellite.

"Charon is half as big as Pluto," said Mark Showalter, a planetary scientist at the SETI Institute who is involved in efforts to search for hazardous debris along New Horizons' flight path at Johns Hopkins University Applied Physics Laboratory. "So that's the consensus: Charon is debris from this collision."

But the collision picture is far from complete.

"The question is the little guys," said Showalter, meaning the smallest moons Styx, Nix, Hydra and Kerberos. The collision theory sounds really good, he said, except that no one has been able to reproduce the system accurately in a model. So all bets are off until there is more data -- which New Horizons could very well provide.

Whatever the origins of the Pluto system, the discovery of all four smaller moons in the last 10 years, makes it more likely there could be additional small bodies occupying the space near Pluto. And that adds a whole new layer of stress to New Horizons' flyby on July 15.

"If you fly through this system at 14 kilometers per second (31,000 miles per hour), anything larger than a BB could do damage to the spacecraft," said Showalter. Of course, at 3 billion miles away, there no way to see something that small. So the researchers are focusing on the things that can shed dust and gravel in the vicinity of Pluto.

"In terms of danger to the spacecraft, we are not too worried about any moons outside Charon in near-equatorial orbits," Showalter said. "The reason is that any dust they generate is not likely to get into the path of the spacecraft. We are most concerned about something close to Pluto and/or in a very inclined orbit."

To minimize the danger, Showalter and a team of about ten people are analyzing and modeling every bit of new data as New Horizons approaches Pluto. They are on the lookout for any small moons or faint rings that might not have been seen previously.

Read more at Discovery News

Earth's Mysteriously Light Core Contains Brimstone

Biblical views of the center of the Earth as a hellish pit raging with fire and brimstone have some support from new research. Scientists have found that the vast majority of brimstone — reverently referred to in biblical times as “burning stone,” but now known more commonly as sulfur — dwells deep in the Earth’s core.

“In a way, we can also say that we have life imitating art,” study lead author Paul Savage, a research scientist in the Department of Earth Sciences at Durham University in the United Kingdom, said in a statement.

“For millennia, tales have been told of the underworld being awash with fire and brimstone. Now at least, we can be sure of the brimstone.”

The researchers estimate that the Earth’s core contains 10 times the amount of sulfur than in the rest of the world, or comparable to about 10 percent of the mass of the moon.

Inside Earth

Scientists have generally understood that at the time of Earth’s formation, heavy metals such as iron and nickel sunk to the planet’s core, and light elements, like oxygen, silicon, aluminum, potassium, sodium, and calcium, mostly concentrated in the outer layers of the Earth, in the mantle and crust.

However, the mass of the Earth’s solid inner core, which is too light to be composed solely of metal, has been an enduring inconsistency in our understanding of the planet’s distribution of elements. To explain the core’s lighter-than-expected weight, scientists assumed that the core had to contain some lighter elements, such as oxygen, carbon, silicon and sulfur.

“Scientists have suspected that there is sulphur in the core for some time, but this is the first time we have solid geochemical evidence to support the idea,” Savage said.

Confirming the presence of lighter elements, like sulfur, in the core, provides information about the temperatures, pressures and oxygen content in the Earth’s mantle, which surrounds the core and separates it from the crust on which we walk. “It’d be nice to know what the Earth is formed of, as a fundamental aspect of understanding the Earth,” Savage told Live Science.

Peeling back the layers

Without the technology to dig 1,800 miles (2,900 kilometers, or the equivalent of around 3,000 Eiffel Towers stacked on top of one another), scientists looked for clues created by a 4.47 billion-year-old impact — the moon-forming collision between Earth and a large, planet-size body called Theia.

“The giant impact wouldn’t have just formed the moon; it wouldn’t have just sort of sliced a bit of material off and end up becoming the moon,” Savage said. “The amount of energy involved in this sort of impact would have, if not completely, it would have partially melted the Earth’s mantle to a certain depth.”

When the mantle melted, some of its sulfur-rich liquid seeped into the core, and some of it evaporated into space, he added.

“You could lose a lot of it during evaporation,” Savage said. “Just by looking at the sulfur, we can’t really tell much about how much is in the core versus how much has been lost to space,” making sulfur virtually impossible to directly measure.

To track and quantify the elusive sulfur, the researchers looked to copper isotopes (atoms of the same element with different numbers of neutrons). “We chose copper, because it is a chalcophile element, which means it prefers to be in sulphide-rich material — so it is a good element to trace the fate of sulphur on Earth,” Frédéric Moynier, the study’s senior author and a professor at the Institut de Physique du Globe in Paris, said in a statement.

“Generally, where there is copper, there is sulphur; copper gives us a proxy measurement for sulphur.”

Searching for sulfur

The researchers measured the copper isotope values from both the mantle and core to discover where they would find sulfur. Meteorites were used to represent the “bulk Earth,” which includes the core, mantle and crust. Meteorites are jumbles of extraterrestrial matter that have been orbiting the sun since even before planets formed.

“They’re like cosmic sediments,” Savage said. “If we got a planet and milled it down, if we sort of crushed it up and mixed it around, that’s what we assume would be in meteorites.”

Samples formed from lava eruptions, as well as from tectonic events, which pushed the mantle onto the surface of the Earth, were used to represent so-called “bulk silicate Earth” values, which include the copper content in the mantle and crust. Researchers can then figure out the copper content in the Earth’s core by subtracting the “bulk silicate Earth” value from the “bulk Earth” value.

The scientists measured a heavy “bulk silicate Earth” copper isotope value compared with the “bulk Earth” value, which could indicate that the mantle has a lot of heavy copper and the core does not.

However, through experiments, they found that the “copper in the core should be slightly heavy compared to the mantle — so the core cannot balance out the heavy mantle compared to meteorites, because it is also heavy,” Savage said. If there are a lot of heavy copper isotopes in one part of the Earth, another part will have a lot of light copper isotopes.

To explain copper’s “heaviness” in both the mantle and core, the researchers predicted that a sulfur-rich liquid with “light” copper formed after the impact that created the moon.

“So the [melted mantle] is light, the mantle is heavy, and the two, when mixed together, would equal bulk Earth (meteorites),” Savage said.

After the Earth formed from meteorites and other extraterrestrial matter like dust and rock, it started to melt, forming its core. During core formation, some “heavy” copper left the melting mantle and entered the core, leaving the mantle with “lighter” copper, Savage said. Then, following the giant moon-forming impact, the Earth’s mantle re-melted, forming a sulfur-rich liquid.

Read more at Discovery News

Solstice: How Humans Celebrate Official Start of Summer

Today marks the summer solstice, the official start of summer in the Northern Hemisphere.

This year, the solstice will occur at 12:39 p.m. EDT (1639 GMT), when the sun is directly over the Tropic of Cancer. The summer solstice is also the longest day of the year for places in the Northern Hemisphere, which means daylight will get progressively shorter each day until the winter solstice in December.

For countries north of the Tropic of Cancer, the summer solstice takes place when the Earth’s tilt toward the sun is at a maximum and the sun is directly over countries located across the Tropic of Cancer, such as Mexico, Egypt, India and southern China. After the winter solstice, the shortest day of the year, the sun rises higher and higher in the sky, culminating in the summer solstice when it reaches its highest point.

The summer solstice is recognized all over the world, “although we don’t pay much attention to it. We think more about summer being between the Fourth of July and Labor Day,” said Anthony Aveni, a professor of astronomy and anthropology at Colgate University in Hamilton, New York.

But for ancient humans, the sun was one of the first things they recognized and subsequently used to keep time, Aveni said.

In medieval Germany, people of the Mosel Valley would set a big hoop of straw on fire, dubbing it the “fiery wheel.” The hoop was then rolled down a hill through vineyards, toward the water. “The idea being fire is associated with purity and fertility,” Aveni told Live Science. “This is the time of year when the landscape is fertile.”

In northern Germany, a prehistoric site called Externsteine was likely built to celebrate the summer solstice, said Michael York, an independent scholar of cultural astronomy and astrology. Externsteine is a well-known rock formation consisting of five massive sandstone pillars. At the top of one of the pillars is a roofless chapel with a small alter carved out of the rock. A hole on the alter lights up at sunrise on the summer solstice, York said.

Another giant monument, Britain’s Stonehenge, may have been created to celebrate the summer solstice, according to Aveni.

“Stonehenge was intended to be a sun temple from its very inception. It seems to have been arranged deliberately so that a viewer who stands in the center of the great stone ring could capture the rising sun’s disk in the Heel Stone gateway to the northeast on June 21 — the day the sun reached its northern standstill,” Aveni wrote in his book, “The Book of the Year: A Brief History of Our Seasonal Holidays” (Oxford University Press, 2004).

Read more at Discovery News