Jan 14, 2017
ESO, represented by the Director General, Tim de Zeeuw, has signed an agreement with the Breakthrough Initiatives, represented by Pete Worden, Chairman of the Breakthrough Prize Foundation and Executive Director of the Breakthrough Initiatives. The agreement provides funds for the VISIR (VLT Imager and Spectrometer for mid-Infrared) instrument, mounted at ESO's Very Large Telescope (VLT) to be modified in order to greatly enhance its ability to search for potentially habitable planets around Alpha Centauri, the closest stellar system to the Earth. The agreement also provides for telescope time to allow a careful search programme to be conducted in 2019.
The discovery in 2016 of a planet, Proxima b, around Proxima Centauri, the third and faintest star of the Alpha Centauri system, adds even further impetus to this search.
Knowing where the nearest exoplanets are is of paramount interest for Breakthrough Starshot, the research and engineering programme launched in April 2016, which aims to demonstrate proof of concept for ultra-fast light-driven "nanocraft," laying the foundation for the first launch to Alpha Centauri within a generation.
Detecting a habitable planet is an enormous challenge due to the brightness of the planetary system's host star, which tends to overwhelm the relatively dim planets. One way to make this easier is to observe in the mid-infrared wavelength range, where the thermal glow from an orbiting planet greatly reduces the brightness gap between it and its host star. But even in the mid-infrared, the star remains millions of times brighter than the planets to be detected, which calls for a dedicated technique to reduce the blinding stellar light.
The existing mid-infrared instrument VISIR on the VLT will provide such performance if it were enhanced to greatly improve the image quality using adaptive optics, and adapted to employ a technique called coronagraphy to reduce the stellar light and thereby reveal the possible signal of potential terrestrial planets. Breakthrough Initiatives will pay for a large fraction of the necessary technologies and development costs for such an experiment, and ESO will provide the required observing capabilities and time.
The new hardware includes an instrument module contracted to Kampf Telescope Optics (KTO), Munich, which will host the wavefront sensor, and a novel detector calibration device. In addition, there are plans for a new coronagraph to be developed jointly by University of Liège (Belgium) and Uppsala University (Sweden).
Detecting and studying potentially habitable planets orbiting other stars will be one of the main scientific goals of the upcoming European Extremely Large Telescope (E-ELT). Although the increased size of the E-ELT will be essential to obtaining an image of a planet at larger distances in the Milky Way, the light collecting power of the VLT is just sufficient to image a planet around the nearest star, Alpha Centauri.
Read more at Science Daily
|Gedanohelea gerdesorum in 54 million-year-old Cambay amber from India: The insects are only around a millimeter large and can often be found in Indian amber. Today, too, other biting midge species are widespread and well researched.|
India harbours many unique species of flora and fauna that only occur in this form on the subcontinent. The prerequisite for such a unique development of species is that no exchange takes place with other regions. For a long time, scientists assumed that India was isolated in this way due to continental drift. The supercontinent Gondwana, which included South America, Africa, Antarctica, Australia, Madagascar and India, broke up over the course of geological history. What is now India also began moving towards the north east around 130 million years ago. It was common belief among researchers that, before it collided with the Eurasian plate, India was largely isolated for at least 30 million years during its migration.
However, according to current findings by paleontologists at the University of Bonn, the Indian subcontinent may not have been as isolated on its journey as we have thought. "Certain midges that occurred in India at this time display great similarity to examples of a similar age from Europe and Asia," says lead author Frauke Stebner from the working group of Prof. Jes Rust at the Steinmann Institute at the University of Bonn. These findings are a strong indicator that an exchange did occur between the supposedly isolated India, Europe and Asia.
Mining for amber in the Indian coal seams
The scientist from the University of Bonn mined for amber in seams of coal near the Indian city of Surat. Small midges, among other things, were encased in tree resin 54 million years ago and preserved as fossils. The tiny insects, which are often not even a millimeter large, are "biting midges." Their descendants can still be found today in Germany in meadows and forests -- where the little beasts attack you in swarms and suck your blood.
The paleontologist investigated a total of 38 biting midges encased in amber and compared them with examples of a similar age from Europe and China. Scientists from the University of Gda?sk (Poland) and Lucknow (India) were also involved in this. It has been possible to assign a total of 34 of these insect fossils to genera that are already known. "There was significant conformity with biting midges in amber from the Baltic and Fushun in north-east China," reports Stebner.
Chains of islands presumably created a link to India
How the insects were able to spread between drifting India and Eurasia has not yet been clarified fully. "Nevertheless, it also seems to have been possible for birds and various groups of mammals to cross the ocean between Europe and India at the time," the paleontologist refers to studies by other scientists. However, it has now been possible for the first time, with the aid of biting midge fossils, to also demonstrate an exchange between India and Asia in this period.
Read more at Science Daily
Jan 13, 2017
That's according to new research by scientists with the Potsdam Institute for Climate Impact Research (PKI), who argue, in a new study published in the journal Geophysical Research Letters, that droplets of sulfuric acid forming high in the air after the impact brought about a long-lasting plunge in temperatures, playing a key role in the demise of the dinosaurs at the end of the Cretaceous.
"The long-term cooling caused by the sulfate aerosols was much more important for the mass extinction than the dust that stays in the atmosphere for only a relatively short time," said study lead Georg Feulner, in a statement. "It was also more important than local events like the extreme heat close to the impact, wildfires or tsunamis."
Existing studies, the PKI team wrote, "focused on the effect of dust or used one-dimensional, non-coupled atmosphere models." Feulner and his team instead used new computer models that coupled atmosphere, ocean and sea ice data in order to run their simulations.
The resulting post-impact computer models painted a dire picture for dinosaurs accustomed to a lush environment: a global mean surface air temperature drop of at least 26 degrees C.; three to 16 years of sub-freezing temperatures; and a climate recovery time of more than 30 years.
|Computer modeling showed an enduring chill passing over the planet after the asteroid strike.|
All was chaos in the oceans, too, the models showed. As surface waters cooled, they grew heavier and denser, sinking. Meanwhile warmer waters farther below rose, bringing with them nutrients that created huge algae blooms. The blooms could have created toxic substances that impacted life along the coastlines, the scientists suggested.
Read more at Discovery News
The rural festival, held every January in snow-swept Toyama prefecture, central Japan, sees revelers pouring rice wine into a fish's mouth in a "Carp Releasing Exorcism" said to purge people of evil spirits.
But the bizarre Shinto ritual has become entangled in controversy after featuring on national television earlier this week, with images of the flapping carp triggering an online backlash from upset viewers, many accusing organizers of animal cruelty.
Many of those who tweeted or posted to online chat rooms called for an end to the "abusive practice" and accused organizers of "intoxicating wildlife."
During the ceremony, said to date back to the early 19th century, men and women hoping for a karmic boost are blessed by a priest.
The men then each hold a carp – a sacred fish in Japan – while a woman pours the purifying alcohol into the creature's mouth before it is released back into the water.
But after Japan's Asahi TV aired coverage of the event, a Twitter storm suggested many viewers disapproved of putting the fish's health in peril.
"It just seems like abuse," wrote one, while another called it "harassment" of the fish.
Organizers acknowledged to the news site J-Cast that they had received several complaints from the public.
The ceremony's defenders insisted it was part of Japan's cultural heritage, with one online comment complaining: "People are too uptight these days."
TV Asahi's Morning Show interviewed a fish expert who claimed that alcohol does not harm the animal as the toxic liquid escapes through the gills.
The outcry is the latest in what looks like a fledgling movement to protect the rights of fish in Japan.
Last November a Japanese skating rink that froze 5,000 dead fish under the ice as an attraction for visitors was forced to close after receiving a barrage of criticism.
From Discovery News
Scientists from the University of California San Diego (UC) and the Western Australia (WA) Museum went looking for the creature in waters off western Australia and hit a biological home run: almost 30 minutes of video (see below) featuring two Ruby seadragons.
The creature has only been known since early in 2015, when researchers confirmed the animal as a third seadragon species (joining the Common and Leafy varieties). That identification was made from CT scans of a small group of specimens – one of which a century old – previously thought to have been those of Common seadragons.
Seadragons are marine fish in the same taxonomic family as pipefish and seahorses. They live off Australia's coast, among reefs and beds of seaweed, dining on zooplankton and very small crustaceans.
The fiery new animal stands in visually stark contrast to the orange-tinted Leafy sundragon and the yellow/purple Common, and that's not the only difference, the researchers found.
Thanks to the video footage, researchers now know for sure that Ruby seadragon doesn't have the leaf-like appendages common to the other two species. The missing feature was documented in the CT scans of the earlier specimens, but before the live footage there was no way of knowing if this was how Ruby seadragons really looked or if the appendages had somehow been lost during collection.
|Common (above) and Leafy seadragons have leaf-like appendages for camouflage, a feature lacking in the new Ruby species.|
The Common and Leafy seadragons use the appendages for camouflage among seaweed, and researchers suspect the Ruby red version uses its color as camouflage instead: They think the creature inhabits deeper waters than its cousins, at depths where the red shading would be absorbed and serve as its own camouflage.
Read more at Discovery News
The evidence—reported in the journal Palaeogeography, Palaeoclimatology, Palaeoecology—consists of fossilized bones from animals that megalodon devoured. Riddled with the enormous shark's bite marks, the fossils are the first to show exactly what species the megalodon consumed in its diet.
All of the fossils were unearthed at a site called Aguada de Lomas in southern Peru.
Lead author Alberto Collareta of the University of Pisa and his team analyzed the fossils and determined that megalodon, which could grow to over 53 feet long, ate the now-extinct baleen whale Piscobalaena nana and the early seal Piscophoca pacifica. Both animals were still impressive in size, at just under 16.5 feet long, but were presumably easy, nutritious pickings for megalodon.
"What else would you eat but a large marine mammal?" Christina Slager, director of animal care and exhibits for San Francisco's Aquarium of the Bay, told Seeker when told of the new findings.
She said that great white sharks today like to eat seals and sea lions, but will usually only scavenge on whales. Except for the pygmy right whale, all other baleen (filter-feeding) whales today greatly surpass even the biggest great white sharks in size.
Kenshu Shimada, a professor of paleobiology at DePaul University, explained to Seeker that whales have likely become bigger than sharks "due to the evolution of their migration behavior where large body sizes must have helped them to travel long distances and exploit food sources not only along the coasts but also in the middle of the ocean."
He added, "Whether megalodon migrated long distances can only be speculated at the present time."
Uncertainty also exists concerning how megalodon interacted with its whale prey. Collareta and his colleagues admit that "it is virtually impossible to discriminate between active predation and scavenging when dealing with fossil specimens," yet they believe it is possible megalodon actively hunted small-sized whales.
In fact, one of the fossils is a whale skull that the shark bit directly into, going right after the head meat. This and the other bite marks unmistakably were made by megalodon, according to the researchers. One tooth mark alone, they say, measured over 2 inches long.
|Megalodon tooth next to great white shark teeth.|
Slager said that the traditional explanation for the giant shark's disappearance has been climate change.
"Based on its remains, megalodon preferred warmer waters," she said. "The Ice Age began when this species went extinct, but other factors in addition to climate change could explain why the shark died out."
Collareta and his team note that various lineages of small baleen whales experienced population crashes just before megalodon's disappearance. Slager agreed that this is likely not just a coincidence, and that lack of food could have contributed to the iconic shark species' demise.
Shimada explained, "Most sharks are opportunistic generalists capable of feeding on variety of organisms, but some forms with specialized diets, such as plankton, may be particularly prone to extinction if a major shift in global oceanic conditions takes place." He added that this was the probable fate of a group of plankton-eating bony fishes, called suspension-feeding pachycormids, which bit the dust at the end of the Dinosaur Era about 65 million years ago, when global populations of plankton collapsed.
Shimada said the jury is still out, however, on what precise factors did in megalodon.
The disappearance of both the early small baleen whales and megalodon could reveal "a process of co-extinction of prey and predator," Collareta and his team believe.
Read more at Discovery News
In an article published in the journal Acta Chiropterologica, researchers in the country have documented for the first time the presence of human blood in the feces of the hairy-legged vampire bat (Diphylla ecaudata).
D. ecaudata is one of just three bat species that live like vampires – depending solely on blood for their food. (Desmodus rotundus and Diaemus youngi are the others.) The short-snouted bat lives in South and Central American forests as well as the southern portions of Mexico.
The bats studied came from dry forests in northeastern Brazil, and their penchant for human blood was a surprise, study co-author Enrico Bernard told New Scientist: "This species isn't adapted to feed on the blood of mammals."
Indeed the animal was thought to dine exclusively on birds and was considered to have the most specialized diet of the three vampire species. However, "our results suggest that the diet of D. ecaudata is more flexible than expected," the researchers wrote.
The prospect of humans now being dined on by the bat could be a worrisome prospect. The animal can potentially transmit rabies to humans, and Brazil has a history of vampire bat attacks.
In the end, the addition of people's blood to the mix may be out of simple necessity.
"The record of humans as prey and the absence of blood from native species may reflect a low availability of wild birds in the study site, reinforcing the impact of human activities on local ecological processes," the researchers wrote.
From Discovery News
Jan 12, 2017
Consensus has long been that the center of the planet is composed of about 85 percent iron and 10 percent nickel, with sulphur, oxygen and silicon prime candidates for the other five percent.
But geophysicist Eiji Ohtani at Tohoku University in northern Japan and his research team suggest that silicon is the most likely answer.
Ohtani's team conducted experiments on iron-nickel alloys mixed with silicon, subjecting them in the lab to the kinds of high temperatures and pressure found in the inner core.
The team discovered that the data for the mixed material observed with X-rays matched seismic data — namely, sound velocity, or seismic waves — obtained for the inner core.
"Our latest experiments suggest that the remaining five percent of the inner core is composed mostly of silicon," Ohtani told AFP.
He said that the finding helps understand whether the Earth's surface was rich in oxygen in its early formation before photosynthesis began as oxygen has been another potential candidate for the mystery element in the Earth's inner core.
Ohtani cautioned that more work needs to be done to confirm his findings on silicon.
Some scientists say that if the Earth's inner core contains silicon then it means the rest of the planet must have been relatively oxygen rich at the time of its formation, because oxygen that they believe existed when the planet was formed was not confined to the inner core.
But if the mystery element in the core is oxygen then the rest of the Earth was oxygen-poor in the beginning.
Ohtani said he does not think oxygen now exists in the inner core, citing the difficulty for silicon and oxygen to co-exist in the same place.
"But it doesn't necessarily mean the rest of the planet was oxygen rich because there is a possibility that oxygen did not exist as an element of the Earth at its formation in the first place."
The Earth is believed to be made up of three main layers: the solid outer layer where creatures including humans live, the mantle which is made up of hot magma and other semi-solid materials, and the core at the centre.
The core comprises an outer layer of liquid iron and nickel, and an inner layer — a hot dense ball of mostly iron.
Read more at Discovery News
So says a new study in the January 12 issue of the journal Cell.
Thanks to its use of optogenetics – a way to stimulate specific neurons with laser light – the Yale team was able to isolate one set of neurons that controls the pursuit of prey and another that signals the use of the jaw and neck muscles to bite down and deliver the kill to prey.
"We'd turn the laser on and they'd jump on an object, hold it with their paws and intensively bite it as if they were trying to capture and kill it," said study lead Ivan de Araujo in a statement.
By "object," the researcher meant pretty much anything – even bottle caps and wooden sticks were not safe from the pounce, if a mouse's hunting neurons were lit by the laser.
de Araujo pointed out that the aggression he and his team were able to stimulate in the rodent was not an all-purpose emotion. "The system is not just generalized aggression," he said. "It seems to be related to the animal's interest in obtaining food." The scientists observed that mice that were hungrier went harder after prey objects – sometimes live crickets, sometimes the bottles and sticks – than did mice that were less in the mood for food.
de Araujo had been interested in gaining a better understanding of the neural mechanisms at work when animals engage in feeding behavior, and poring over other research he zeroed in on a brain area that dealt almost singularly with hunting but not eating: the central nucleus of the amygdala, which was also linked to control over hunting muscles like such as the neck and jaw.
Predatory behavior among jawed vertebrates like mice – and humans – de Araujo said, is "a major evolutionary player in shaping the brain." So, he thought: "There must be some primordial sub-cortical pathway that connects sensory input to the movement of the jaw and the biting."
The authors write that the mechanisms in the vertebrate brain that control hunting are not well known. Now, though, they say they have documented a critical player in the process. Their findings, they say, "suggest that central amygdala neurons instruct predatory hunting across jawed vertebrates."
From Discovery News
Although astronomical measurements detected the presence of an atmosphere at Pluto long before the NASA New Horizons flyby in July 2015, very little was known about how much was being eroded into space by the continuous stream of solar wind particles. New Horizons measurements, however, proved that the rate of atmospheric loss was 100 times less than expected and, in new research published this week in the journal Icarus, researchers think they know what might be protecting Pluto's tenuous atmospheric gases.
Researchers from Georgia Institute of Technology have shown that when Charon orbits between Pluto and the sun, its presence can modify the dwarf planet's bow shock — a standing shock wave that appears "upstream" of Pluto as the solar wind particles encounter Pluto's thin atmosphere, like the wave that roils in front of a boat's bow when it powers through water — thereby shielding Pluto's atmosphere for a short time. Charon maximizes this protection should it also have an atmosphere, but its protective impact is minimal when it either doesn't have an atmosphere or when it is positioned "downstream" of Pluto.
As Pluto and Charon orbit so close to one another, the pair are believed to share atmospheric gases and when Charon passes behind Pluto particles originating from Pluto are deposited at the moon's poles, appearing as a dark brown deposit in New Horizons observations.
As Pluto is located so far away from the sun in the Kuiper Belt, the impact of the solar wind is much lower than its impact on planets closer to the sun. The space weather impact has been reduced even further with the help of Charon.
"As a result, Pluto still has more of its volatile elements, which have long since been blown off the inner planets by solar wind," said Georgia Tech student John Hale. "Even at its great distance from the sun, Pluto is slowly losing its atmosphere. Knowing the rate at which Pluto's atmosphere is being lost can tell us how much atmosphere it had to begin with, and therefore what it looked like originally. From there, we can get an idea of what the solar system was made of during its formation."
As Pluto and Charon orbit so close, and Charon is roughly half the size of its dwarf planet buddy, the pair orbit a common point in space known as the "barycenter." This orbital oddity added fuel to the debate as to whether Pluto should be called a dwarf planet, or whether Pluto and Charon should be designated a "binary planet." Now, with more findings about the pair's atmospheric interactions, it could be argued that the case for calling Pluto a binary planet is as valid as ever.
From Discovery News
Draining these peatlands for agriculture, or reduced rainfall due to climate change, would release massive amounts of planet-warming greenhouse gases, they warned in a study published in Nature magazine.
"We found 30 billion tonnes of carbon that nobody knew was there," said Simon Lewis, co-lead author of the study and a professor at the University of Leeds.
"If the Congo Basin peatlands were to be destroyed, it would release billions of tonnes of CO2 into the atmosphere," he told AFP. "Keeping that carbon locked up" should be a priority."
Peatlands are carbon-rich ecosystems that cover three percent of Earth's land surface, but store about a third of all soil carbon.
Most peat — dense, dark-brown muck composed of decaying plants — is located in Canada, Scandinavia and Siberia, but the tropics hold large stores as well.
Until the mid-20th century, it was often cut into bricks, dried and burned as a fuel.
More recently, however, scientists have understood that peatlands, which are at least a food (30 centimeters) thick, harbor vast stores of carbon in the form of the greenhouse gases that are driving global warming.
The Congo Basin peatland averages about six feet (2 meters) in thickness.
Most climate change in caused by burning oil, gas and coal to power our economies, but a 10th of global emissions come from land use, mainly deforestation and agriculture.
In Southeast Asia — notably in Indonesia — vast expanses of peatland have been stripped of wetland forests and drained to make way for commercial crops, especially palm oil.
That process not only releases CO2 and nitrous oxide — another potent greenhouse gas — into the atmosphere, it also creates health-wrecking pollution when forests are burned.
Haven for Gorillas
The Congo Basin's Cuvette Centrale peatlands — astride the Republic of Congo and the Democratic Republic of Congo — "are currently relatively undisturbed," said Emma Stokes, director of the Wildlife Conservation Society's Central Africa program.
"But palm oil is starting to happen in Africa," she said by phone, referring to the possibility of peatlands being sacrificed to make the way for plantations.
"It is not an immediate risk, but we can't all sit back and not worry about it," she said.
And while there is some concern among climate scientists that global warming many be decreasing the area's rainfall, there is not enough evidence so far to know.
Simon, who discovered the massive peatlands and helped map its contours, explained how a 56,000-square-mile (145,500-square-kilometer) patch could escape notice for so long.
To start with, the buried organic matter does not form near rivers, which are often the only transport arteries in sparsely populated tropical forests.
Read more at Discovery News
What's more, the movements of these gibbons were dazzling, with their seemingly effortless ability to leap high in the treetops. The name "Skywalker" from "Star Wars" came to the minds of the sci-fi fan scientists.
DNA and other analysis determined that the gibbons represent a new species, Hoolock tianxing sp. nov., which has been nicknamed "Skywalker." It is described in the latest issue of the American Journal of Primatology.
Hoolocks are the second-largest of the gibbons, after the siamang.
"We wish to see the 'Return of the Jedi,' the Skywalker hoolock gibbons, to the forests," co-author Kai He of the Chinese Academy of Science's Kumming Institute of Zoology, told Seeker, referring to how so few of these primates appear to still exist.
He and his team already believe that the gibbon should be categorized as "endangered" under IUCN criteria.
Kai He, lead author Peng-Fei Fan and their colleagues found that different species of gibbons evolved around large rivers, which are barriers to the movements of these animals.
|'Skywalker' gibbon (Hoolock tianxing sp. nov.) moving from tree to tree.|
"Our exhibit is surrounded by a mote, which they avoid because they don't like water," Stith said.
She added that they have "super dense hair," having hundreds of additional hairs per inch than humans do. The thick coat helps to keep their skin dry in moist rainforest habitats, but is another impediment to swimming, Stith explained.
Researchers in Asia have struck species gold of late by exploring remote rivers. Kai He, for example, said that a recently discovered species of Myanmar snub-nosed monkey, Rhinopithecus strykeri, was found to be isolated from its sister species, Rhinopithecus bieti, by the Salween River.
"Rivers in southwestern China and northern Myanmar have played an important role in shaping speciations, not only in primates, but also other terrestrial species," he said.
It remains to be seen how our own species might have been shaped by barriers like large rivers, particularly early in human evolution when our ancestors had more body hair and were better adapted to life in the trees.
Gibbons are not too far down on the human family tree either, given that they are closely related to chimpanzees, gorillas and orangutans. They actually share many features with us, according to the Tree of Life web project, since they have no tail, maintain a semi-erect posture, have an adaptation that allows them to turn their hands palm-side upwards, have a big brain and more.
Some might even say that gibbons connect too well with us, which could explain why they are so coveted in the illegal pet trade. In some U.S. states, it is even still legal to own a pet primate.
"They're very cute," Stith admitted, admiring her own vocal charges at the zoo.
Read more at Discovery News
Jan 11, 2017
Announced by Mahmoud Afifi, head of Ancient Egyptian Antiquities Department at the Ministry of Antiquities, the remains were discovered in a 3,400-year-old necropolis which was uncovered in 2015 at Gebel el Sisila, a site north of Aswan known for its stone quarries on both sides of the Nile. Blocks used in building almost all of ancient Egypt's great temples were cut from the site.
The burials date from the reign of Pharaohs Amenhotep II and Thutmose III of the famous 18th Dynasty, which includes some of Egypt's most famous kings, including King Tut.
"So far we have excavated 26 rock-cut tombs dating back to 3,400 years ago. From these burials we have recovered more than 80 individuals of varying ages and sex," Lund University archaeologist Maria Nilsson, director of the Gebel el Silsila Survey Project, told Seeker.
The findings include three crypts also cut into the rock, two niches possibly used for offerings, one tomb containing multiple animal burials, and three individual child burials.
Nilsson and associate director John Ward worked in cooperation with the Ministry of Antiquities as well as Kom Ombo and Aswan Inspectorates under General Directors Abd el Menum and Nasr Salama respectively.
|Some of the rock-cut tombs found at Gebel el Sisila.|
Two of the three infant burials were located some distance from any other tomb, and so were isolated from their parents or sibling burials, if any.
"The accompanying grave goods and the protective amulet suggest that great care was taken with the burial. However, the question arises as to why these children are separated from the main tombs within the necropolis," Ward told Seeker.
In another single chamber room, Nilsson's team found a crypt with a dozen of sheep and goats, and a couple of Nile perch. While the fish remains could easily have been brought in with a Nile inundation, it is not clear yet why there were so many sheep and goat remains secreted within the crypt.
"One possibility is that sheep and goat were used in sacrificial offerings in the necropolis," Nilsson said.
More puzzlingly, an almost complete adult crocodile was discovered resting on the floor in the courtyard immediately outside the crypt.
"Its tail was orientated towards the south while its head, which was missing, would have been in the north," Ward said.
|3D reconstruction of the crocodile found in the necropolis.|
Moreover, Nilsson and Ward discovered another crocodile a little further north laying in a similar position, although this time the tail was pointing north and the head, again missing, lay toward the south.
"We can not verify that these crocs were deliberately placed within the necropolis, or whether they died of natural causes. But to find two in similar circumstances is worthy of further research and analysis," Ward said.
Read more at Discovery News
The unintended donor, known as the Sagittarius dwarf, is one of dozens of miniature galaxies that loop around the Milky Way. The Sagittarius dwarf is located about 3.4 million light-years away from Earth.
Computer simulations show that Sagittarius paid a price each time it flew by its bigger neighbor. The Milky Way's heftier gravitational tug has stripped away about one-third of the dwarf galaxy's stars and 90 percent of its dark matter, a paper to be published in The Astrophysical Journal shows.
"This resulted in three distinct streams of stars that reach as far as one million light-years from the Milky Way's center. They stretch all the way out to the edge of the Milky Way halo and display one of the largest structures observable on the sky," the Harvard-Smithsonian Center for Astrophysics wrote in a press release.
The finding stems from research showing that five of the Milky Way's 11 most distant stars are located about 300,000 light-years from Earth, well outside the Milky Way's spiral disk.
Graduate student Marion Dierickx and Harvard theorist Avi Loeb ran computer simulations to map out the dwarf galaxy's travel itinerary for the last 8 billion years, adjusting its initial velocity and angle of approach to the Milky Way to match current observations of the straggler stars.
"The starting speed and approach angle have a big effect on the orbit, just like the speed and angle of a missile launch affects its trajectory," Loeb said in the press release.
The research shows that the five stars have positions and velocities indicating they were stripped from the Sagittarius dwarf billions of years ago.
The other six distant Milky Way residents do not appear to be from Sagittarius, but they might have emigrated from a different dwarf galaxy, the research shows.
Meanwhile, Dierickx and colleagues remain on the hunt for other Sagittarius transplants.
From Discovery News
A new analysis of zircon fragments trapped in rock samples retrieved by the Apollo 14 astronauts shows that the moon is 4.51 billion years old, meaning it formed within 60 million years of the birth of the solar system.
A previous study based on the same samples also showed the moon formed early, within 68 million years of the solar system's birth. Other estimates of the moon's age range from 100 million to 200 million years after the solar system's formation.
The discovery, published in this week's Science Advances, means Earth may have emerged from its battered youth years sooner than thought, setting an early stage for life.
"If we believe that the moon was formed by one giant impact — or several smaller impacts during a short period, as proposed in the Nature Geoscience paper published on Monday — then whatever the proto-Earth looked like before was wiped out," University of California Los Angeles geologist Melanie Barboni wrote in an email to Seeker.
Today's Earth, with atmosphere, liquid surface water and other life-friendly conditions, only started to develop after the impact or impacts that formed the moon, so if that occurred late then life could only have developed late as well, she added.
"Our age places the impact(s) really early, which allow an hospitable Earth to develop much earlier as well," Barboni said.
The finding dovetails with related research showing early Earth was habitable earlier than previously thought, with the potential for life as far back as 4.1 billion years ago.
Having a moon-forming impact or impacts 4.3 billion years ago would leave relatively little time for life to evolve.
"At 4.51 billion years, you have much more time to transform the Earth from hellish to nice," Barboni said. "The age of the moon is indeed critical."
To determine the moon's age, Barboni and colleagues used a new technique to examine eight zircon fragments left over from a previous study. Their uranium-lead dating method, used for the first time on lunar samples, corrects for cosmic ray exposure. The researchers also analyzed isotopes of the element hafnium, a silvery grey metal.
Like on Earth, the zircon fragments originated in magma rocks that were later weathered into sand and small pebbles. These were then incorporated into new rock.
Read more at Discovery News
Researchers from the University of Toronto (UT), in a new study in the journal Nature, say they have found a taxonomic home for the hyolith, a cone-shaped marine animal that had stubbornly resisted definitive classification.
Hyoliths were part of the "Cambrian Explosion" of animals that took place more than 500 million years ago. They diversified and spread themselves out to marine ecosystems everywhere, holding on until about 252 million years ago, when they went extinct.
The animals had long, conical shells and a smaller shell that functioned as a kind of cap to cover the long shell's opening.
The creature was commonly considered to be within the same family as squid and snails, until more than 1,500 specimens from the famed Burgess Shale fossil site in British Columbia showed otherwise.
The specimens examined by the UT researchers had something in their favor that allowed the animal to finally be classified, something characteristic of Burgess Shale fossils: well-preserved soft tissue.
The tissue allowed the scientists to identify a feeding structure on the animal that featured a group of tentacles protruding out from the mouth. The feeding apparatus is called a lophophore, and the scientists say it is found in only one other place today: brachiopods, small marine animals – 0.04 to just under 4 inches long – with hard shells (valves) top and bottom and a hinged opening for feeding time.
"Only one group of living animals - the brachiopods - has a comparable feeding structure enclosed by a pair of valves. This finding demonstrates that brachiopods, and not mollusks, are the closest surviving relatives of hyoliths," said study lead Joseph Moysiuk in a statement.
The find also told the scientists how the creature ate its meals. "It suggests that these hyoliths fed on organic material suspended in water as living brachiopods do today, sweeping food into their mouths with their tentacles," Moysiuk said.
Now, a marine animal that was once "an orphaned branch on the tree of life," according to co-author Jean-Bernard Caron, has found its place.
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The research team noticed the shadow after analyzing 18 years' worth of observations of TW Hydrae, which is about 8 million years old and lies 192 light-years from Earth, in the constellation Hydra. The images, taken by NASA's Hubble Space Telescope, showed that the shadow rotates around the 41-billion-mile-wide (66 billion kilometers) disk once every 16 years.
"This is the very first disk where we have so many images over such a long period of time, therefore allowing us to see this interesting effect," study lead author John Debes, of the Space Telescope Science Institute in Baltimore, said in a statement. "That gives us hope that this shadow phenomenon may be fairly common in young stellar systems."
An unseen exoplanet is the best explanation for the shadow, Debes and his colleagues said. If they're right, the alien world itself isn't casting the shadow; rather, the planet's gravity has twisted and tilted the inner portion of the dust-and-gas disk, blocking starlight headed toward the outer reaches.
|This diagram reveals the proposed structure of a gas-and-dust disk surrounding the nearby young star TW Hydrae|
The putative planet must be about five times more massive than Jupiter to sculpt the inner disk in this manner, the researchers added.
The results — which Debes presented Saturday (Jan. 7) at the 229th meeting of the American Astronomical Society in Grapevine, Texas — map out a promising new way to hunt for infant planets in the inner portions of the disks surrounding young stars, study team members said.
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