The genome of the ocean sunfish (Mola mola), the world's largest bony fish, has been sequenced for the first time by researchers from China National Genebank at BGI-Shenzhen and A*STAR, Singapore. The researchers, who include Nobel Laureate Sydney Brenner, publish their results in the open access journal GigaScience. The ocean sunfish genome revealed several altered genes that may explain the fast growth rate and large size of the fish as well as its unusual endoskeleton.
The ocean sunfish, which can be found in tropical and temperate sea zones such as the Mediterranean and the Atlantic, can grow up to a length of 2.7m and weigh 2.3 tons. Even though its diet, which consists mostly of jellyfish, is nutritionally poor, the ocean sunfish grows at an unusually fast rate of almost one kilogram per day -- other fishes grow at 0.02 to 0.5 kilogram per day. As well as the extreme growth rate, females can produce more eggs than any other known vertebrate (up to 300,000,000 at a time). The ocean sunfish lacks a tail giving it a truncated appearance.
Byrappa Venkatesh, who initiated and co-led the project from A*STAR, said: "We sequenced the pufferfish (Takifugu rubripes) genome in 2002, the second vertebrate genome to be sequenced. Pufferfish and ocean sunfish belong to the same Order but differ dramatically in morphology. So we were keen to sequence the ocean sunfish genome and compare it with the pufferfish genome, to identify genetic changes that have occurred in the ocean sunfish lineage and that might give clues to the highly derived phenotype of the ocean sunfish."
The researchers hypothesized that the ocean sunfish's unusual appearance may be due to the loss of HOX genes that control the body plan of an organism on the head-tail axis by specifying which parts of the body -- such as head, thorax or abdomen -- the different segments of an embryo will form. They were surprised to find out that this wasn't the case, as they discovered that the ocean sunfish possessed HOX gene clusters similar to that of pufferfish.
Focusing on the genetic background of the ocean sunfish's fast growth rate and unusual body shape, the researchers also discovered that several genes involved in growth hormone signalling evolve very fast in the ocean sunfish when compared to other bony fishes, which may explain its large size and fast growth rate.
Unlike other bony fishes, the ocean sunfish's skeleton is largely made up of cartilage and not bone. Looking for clues to why this is the case, the researchers analysed genes that are known to be involved in bone formation.
Guojie Zhang, who is Associate Director at the China National Genbank and co-led the project, said: "We found changes in genes encoding for cartilage formation. This may contribute to the development of predominantly cartilaginous skeleton in this gigantic fish."
Identification of the genomic changes that underlie the ocean sunfish's unusual body shape, size and skeleton using this reference genome could facilitate future studies into the ocean sunfish and the genetic basis of its difference from other fishes, according to the researchers.
Byrappa Venkatesh said: "Vertebrates exhibit a wide diversity in their morphology, physiology and behaviour. Understanding the genetic basis of this diversity is a major goal of evolutionary biology. We still have a lot to learn from the ocean sunfish genome assembly. One way to pinpoint more genetic changes specific to ocean sunfish would be to sequence more closely related species such as porcupine fish, box fish, triggerfish, and triplespines."
Read more at Science Daily
Sep 10, 2016
|Real CMS proton-proton collisions events in which 2 high energy electrons and two high energy muons are observed.|
Using data from a series of experiments that led to the discovery and first exploration of the Higgs boson at the European Organization for Nuclear Research (CERN) in 2012, the group established what they call the Madala hypothesis, in describing a new boson, named as the Madala boson. The experiment was repeated in 2015 and 2016, after a two-and-a-half year shut-down of the Large Hadron Collider (LHC) at CERN. The data reported by the LHC experiments in 2016 have corroborated the features in the data that triggered the Madala hypothesis in the first place.
"Based on a number of features and peculiarities of the data reported by the experiments at the LHC and collected up to the end of 2012, the Wits HEP group in collaboration with scientists in India and Sweden formulated the Madala hypothesis," says Professor Bruce Mellado, team leader of the HEP group at Wits.
The Wits Madala project team consists of approximately 35 young South African and African students and researchers who are currently contributing to the understanding of the data coming out of the LHC experiments, along with phenomenological investigations from theorists such as Prof. Alan Cornell and Dr. Mukesh Kumar and support in the area of detector instrumentation from Prof. Elias Sideras-Haddad (all from Wits University).
The hypothesis describes the existence of a new boson and field, similar to the Higgs boson. However, where the Higgs boson in the Standard Model of Physics only interacts with known matter, the Madala boson interacts with Dark Matter, which makes about 27% of the Universe.
"Physics today is at a crossroads similar to the times of Einstein and the fathers of Quantum Mechanics," says Mellado. "Classical physics failed to explain a number of phenomena and, as a result, it needed to be revolutionised with new concepts, such as relativity and quantum physics, leading to the creation of what we know now as modern physics."
The theory that underpins the understanding of fundamental interactions in nature in modern physics is referred to as the Standard Model of Physics. With the discovery of the Higgs boson at the LHC in 2012, for which the Nobel Prize in Physics was awarded in 2013, the Standard Model of Physics is now complete. However, this model is insufficient to describe a number of phenomena such as Dark Matter.
The universe is made of mass and energy. The mass that we can touch, smell and see, the mass that can be explained by the Higgs boson, makes up only 4% of the mas-energy budget of the Universe. The rest of the mass in the Universe is simply unknown, yet it makes about 27% of the world around us. The next big step for the physics of fundamental interactions now is to understand the nature of Dark Matter in the Universe: what is it made of? How many different types of particles are there? How do they interact among each other? How does it interact with the known matter? What can it tell us about the evolution of the Universe?
The discovery of the Higgs boson at the LHC at CERN has opened the door into making even more ground-breaking discoveries, such as the observation of new bosons that are linked to forces and particles unknown before. These new particles can explain where the unknown matter in the Universe comes from.
Read more at Science Daily
|Shown is an artist's rendering of a Vivaron haydeni, which lived more than 200 million years ago.|
In new research just published in the journal PeerJ, lead author and Virginia Tech undergraduate researcher Emily Lessner describes the new species Vivaron haydeni, an extinct relative of modern crocodiles that lived around 212 million years ago, when New Mexico was part of the western chunk of Pangea, the supercontinent that later broke apart into the continents we know today.
"These were some of the biggest predators at the time. All dinosaurs were much smaller," said Virginia Tech assistant professor Sterling Nesbitt in a statement. Nesbitt first discovered the fossils during an excavation in 2009, some sample of which were later studied by Lessner.
Vivaron walked on four legs and was as long as 18 feet. Lessner fleshed out that picture thanks to a collection of jaw bones, skull fragments and hip bones from three individuals.
The creature was a carnivorous archosaur, a group of animals encompassing crocodilians and pterosaurs, whose living members today are birds and crocodiles.
The fossils were found in northern New Mexico's Hayden Quarry, and Lessner thinks the site, known as a top spot for paleontologists, could hold more samples of her find.
"It is possible that other bones were not preserved, were previously collected, or are still in the ground," she said.
From Discovery News
Sep 9, 2016
|This graph represents the history and domestication of yeast used for making beer and other types of alcohol are revealed through genomic and phenotypic analyses.|
"The flavor of the beer we drink largely depends on yeast," explains Kevin Verstrepen, a yeast geneticist at the University of Leuven and VIB in Belgium. "We're drinking the best beers now because ancient brewers were smart enough to start breeding yeast before they knew what they were doing. It was really an art."
With a team of bioinformaticians led by Steven Maere, a computational biologist at VIB and Ghent University, and beer scientists from White Labs in California, Verstrepen and his colleagues sequenced the genomes of 157 different strains of yeast used to make beer, wine, spirits, sake, bread, and bioethanol, as well as some used in research labs, to explore the species' evolutionary history. The researchers also experimentally tested traits such as stress tolerance to investigate the interaction between the genome and the yeast's behavior.
According to the analysis, the industrial yeast used today came from only a few ancestral strains. Five large groups separated out genetically, with strains mainly clustered together according to their industrial purpose. Geographic boundaries further divided each category: in one grouping of beer yeast, for example, the strains from Belgium and Germany were closely related, but separate from those in the UK and US.
Brewers use the same yeast to make different types of beer, so beverages such as ales or stouts didn't generally have separate strains associated with them. However, a few distinct strains were associated with beers that have very specific traits, such as the smoky clove-like flavor of German Hefeweizen beer.
Using the genomic data, the researchers traced the common ancestor of the industrial beer and wild yeasts to the 1500s -- before the formal discovery of microbes. "If early brewers had a very good fermentation, they were smart enough to harvest the yeast sediment and use it to inoculate the next batch, even if they didn't know what was floating around in it," explains Verstrepen. "Reusing the microbes to make beer completely separated them from nature. The yeasts were evolving in the brewery."
The research team uncovered a number of genetic patterns related to the domestication process. Wild yeast can sexually reproduce during times of starvation or stress, but today's beer yeasts have lost this ability -- they only have functional genes for asexual reproduction, likely due to their cushier living conditions. "They essentially became sterile," says Verstrepen.
"Four centuries of domestication have also left marks in beer yeast genomes associated with traits that are useful in a brewing environment," says Maere. "In various beer yeast lineages, specific genes have been amplified, deleted, or altered to optimize growth in beer fermenters and beer taste."
In particular, the researchers found evidence for amplification of genes involved in metabolizing typical beer sugars and selection against production of 4VG, an undesirable flavor compound produced by most natural yeasts. "As far as we know, there's no selective advantage in suppressing the production of 4VG" says Verstrepen. "It must have been the brewers saying, 'This tastes good, we're going to reuse it.'" Wine yeasts also displayed a genetic resistance to copper, which is used to fight fungal infections in the vineyard and can end up in the grape juices.
Read more at Science Daily
|Still photos depict a single cycle of a bat's head waggle, intended to help it to focus its hearing and zero in on prey.|
Using high-tech recording devices, Wohlgemuth determined that a bat's fetching head waggles and ear wiggles synch with the animal's sonar vocalizations to help it hunt. The finding, published by the open access journal PLOS Biology, demonstrates how movement can enhance signals used by senses like sight and hearing -- not just in bats, but in dogs and cats, and even in humans.
Bats use sonar-like echolocation -- emitting sounds and listening for the echo -- to detect, track and catch prey; that is well-documented. But lead author Wohlgemuth and his team are the first to show how the head and ear movements factor into the hunt.
The researchers used a novel method to study the head waggles and ear movements of the big brown bat, a common bat species that in the wild hunts in both open and cluttered spaces.
First researchers trained bats to sit on a platform while tracking moving prey -- mealworms attached to a fishing line. Once the bats were trained, the researchers attached reflective markers to the top of the bat's head and both ears. The markers allowed the team to precisely measure the head and ear positions as bats tracked worms moving in various directions.
They found the head waggles, about one per second, occurred when the insect prey changed direction or moved erratically. The ear movements, a flattening and perking imperceptible to the naked eye, happened as the worm grew closer. Though very tiny, the ear twitches help the bat hear the echoes it uses to track and capture the prey.
Most notably, these head and ear movements coordinated with the bat's vocalizations, on a millisecond time scale, allowing the animal to pinpoint prey with considerably more accuracy.
Co-author Cynthia F. Moss, a Johns Hopkins professor and neuroscientist, said other studies on how animals and humans localize sound sources missed the importance of head waggles and ear movements, because laboratories typically observe the subject with a fixed head position. That's not at all how bats or other animals operate in the real world, when their heads are free to move, not restrained.
Read more at Science Daily
|A skull is uncovered at the Bedlam burial ground where it is believed over 20,000 Londoners were buried between 1569 and 1738.|
From 1665 - 1666 the bubonic plague killed 100,000 people in London, almost a quarter of the city's entire population. The disease spread rapidly and burial pits were sometimes created to accommodate the overwhelming number of bodies.
Last year, archaeologists in London believe they came upon one of these pits as excavations were underway at a former burial ground at Liverpool Street for a new rail link across the city, reported CNN. The bodies looked to be buried on the same day as others in the nearby Bedlam cemetery with headstones reading 1665, further leading scientists to believe those in the burial pit were killed by the plague.
During the course of this year-long excavation, 3,500 skeletons have been uncovered.
The osteology department at the Museum of London Archaeology, where all the finds from the Liverpool Street excavation were examined, searched for Yersinia pestis in the skeletons, a bacterium known to cause plague. Teeth were removed from the other remains and sent to the Max Planck Institute for the Science of Human History in Germany for further testing.
Molecular palaeopathologist Kirsten Bos found positive results for Yersinia pestis in the teeth of five out of 20 skeletons she examined, confirming this is the bacteria that caused the bubonic plague.
"We could clearly find preserved DNA signatures in the DNA extract we made from the pulp chamber and from that we were able to determine that Yersinia pestis was circulating in that individual at the time of death," she told the BBC.
Read more at Discovery News
The eerie finding was made in a cave near San Francisco de Borja, a town in the northern Mexican state of Chihuahua. Locals who owned the cave were leveling its floor when they stumbled upon the mummified bird and other archaeological material.
The villagers alerted the archaeologists of the National Institute of Anthropology and History who collected two human skulls and bones, parts of mummified human bodies, deer leather remains -- possibly from clothing or bags -- textile, baskets and one big sea shell.
"The locals told us the macaw was complete, unfortunately the rest of the body was taken away by the earth-moving machine and we could not find it," archaeologist Emiliano Gallaga Murrieta, director of the School of Anthropology and History Northern Mexico, told Discovery News.
"We assume the villagers hit upon a funerary context. It is possible that the macaw was part of the burial offering and is probable that was a pet of at least one of the two individuals," he added.
Since no ceramic from the Middle period of Paquimé (1.060 to 1.340 AD) was found, Gallaga believes the cave is a transition site between the obscure archaic and the early agriculture period, some 3,000 years ago.
Given the importance of the material collected, the archaeologists decided to further excavate the cave floor.
In a strip less than 3 feet wide and 150 feet long, they found the remains of bahareque house structures which were burnt and destroyed, several arrow points from the middle archaic period (about 1000 B.C.), fossilized human feces, ropes and remains of burnt beans, corn cobs, a complete pumpkin and some brown ceramic shards.
Most intriguingly, they found other two human burials.
"Placed against the cave all the way to the rock, there were two bone legs tied with a rope. We believe they belonged to a rather tall adult," Gallaga said.
Small pieces of human bones on a rabbit skin indicated that a small baby had also been buried there.
"The pelvis of the adult was very fragmented, so we need to wait until it is restored to establish whether the individual was a male or a female. It is also too early to tell whether the adult and baby were related," Gallaga said.
He speculates these remains date to 1,000 BC., about 3,000 years ago.
"It is possible the human remains were originally interred somewhere else and re-buried in the cave sometime later. However, we do not know why only half of the body was buried," Gallaga said.
Read more at Discovery News
Sep 8, 2016
|Andrew Wetzel's simulation shows stars in the Milky Way-like galaxy on the left and the same region's dark matter on the right. Image is provided courtesy of Andrew Wetzel.|
New theoretical modeling work from Andrew Wetzel, who holds a joint fellowship between Carnegie and Caltech, offers the most accurate predictions to date about the dwarf galaxies in the Milky Way's neighborhood. Wetzel achieved this by running the highest-resolution and most-detailed simulation ever of a galaxy like our Milky Way. His findings, published by The Astrophysical Journal Letters, help to resolve longstanding debates about how these dwarf galaxies formed.
One of the biggest mysteries of dwarf galaxies has to do with dark matter, which is why scientists are so fascinated by them.
"Dwarf galaxies are at the nexus of dark matter science," Wetzel said.
Dark matter makes up a quarter of our universe. It exerts a gravitational pull, but doesn't seem to interact with regular matter -- like atoms, stars, and us -- in any other way. We know it exists because of the gravitational effect it has on stars and gas and dust. This effect is why it is key to understanding galaxy formation. Without dark matter, galaxies could not have formed in our universe as they did. There just isn't enough gravity to hold them together without it.
The role of dark matter in the formation of dwarf galaxies has remained a mystery. The standard cosmological model has told us that, because of dark matter, there should be many more dwarf galaxies out there, surrounding our own Milky Way, than we have found. Astronomers have developed a number of theories for why we haven't found more, but none of them could account for both the paucity of dwarf galaxies and their properties, including their mass, size, and density.
As observation techniques have improved, more dwarf galaxies have been spotted orbiting the Milky Way. But still not enough to align with predictions based on standard cosmological models.
So scientists have been honing their simulation techniques in order to bring theoretical modeling predictions and observations into better agreement. In particular, Wetzel and his collaborators worked on carefully modeling the complex physics of stellar evolution, including how supernovae -- the fantastic explosions that punctuate the death of massive stars -- affect their host galaxy.
With these advances, Wetzel ran the most-detailed simulation of a galaxy like our Milky Way. Excitingly, his model resulted in a population of dwarf galaxies that is similar to what astronomers observe around us.
As Wetzel explained: "By improving how we modeled the physics of stars, this new simulation offered a clear theoretical demonstration that we can, indeed, understand the dwarf galaxies we've observed around the Milky Way. Our results thus reconcile our understanding of dark matter's role in the universe with observations of dwarf galaxies in the Milky Way's neighborhood."
Despite having run the highest-resolution simulation to date, Wetzel continues to push forward, and he is in the process of running an even higher-resolution, more-sophisticated simulation that will allow him to model the very faintest dwarf galaxies around the Milky Way.
Read more at Science Daily
A team led by archaeologist Carlos Wester La Torre, of the Culture Ministry's Unidad Ejecutora 005 Naylamp, discovered more than 13 burials dating to the 15th and 16th centuries at the Chotuna-Chornancap site in the region of Lambayeque.
The temple and pyramid complex covering over 1500 years of history, the site has yielded the tomb of a 13th century "Chornancap priestess," one of the most powerful people in the Lambayeque culture.
Accompanied by eight other people, the priestess was buried with a copper mask, elaborate jewelry, ceramic offerings and a gold scepter with the image of a Lambayeque god.
According to a statement by the culture ministry unit, the newly discovered graves belong to the later Chimú culture, which had been conquered by the Inca.
Six children were buried in pairs in shallow graves on the east, west and north of the temple's ruins.
Most importantly, the two children interred on the west were footless.
"It appears the feet had been removed intentionally, suggesting they had been sacrificed as an offering and used as 'guardians' of the graves," the Unidad Ejecutora 005 Naylamp said.
Evidence of ritualistic activities and possibly human sacrifices could be also found in the remains of the other adult individuals, men and women, who were buried face-up in narrow and long pits.
At the center of the grave site, the archaeologists found the most prominent person, a male individual who was buried with two clay pots on one side and a sculpted vessel on the other. The vessel appeared to depict the head of a "coquero," a coca leaf-chewer. Another sculpted vessel represented a man standing up and smiling.
"Such offerings appear to be related to some of the characters in a polychrome painting that was discovered earlier in the temple," the archaeologists said.
The painting shows some individuals carrying staffs and some others holding the heads of decapitated people.
"The archaeological excavations in this season have begun to yield results that allow us to reconstruct the function of places such as Chornancap," Wester La Torre said.
"Since the discovery of the priestess' s grave, the site has continued to reveal the complexity of ceremonies and rituals that took place at the temple," he added.
From Discovery News
Scientists from Goethe University and the Giraffe Conservation Foundation (GCF), writing in the journal Current Biology, argue that the lone species of giraffe, Giraffa camelopardalis, and its nine recognized subspecies need to be reshuffled.
Over the last decade, the researchers gathered skin biopsies from more than 100 giraffes, from among all known subspecies. Later DNA analysis of the samples revealed some genetic surprises.
"We found that there are not only one but at least four genetically highly distinct groups of giraffe, which apparently do not mate with each other in the wild," said study co-author and Goethe University professor Axel Janke, in a statement.
"Consequently," he said, "giraffe should be recognized as four distinct species despite their similar appearance."
Here's a quick look at how the new giraffe scorecard should look, Janke and his team suggest:
Giraffa camelopardalis (a.k.a., the Northern giraffe) remains its own species, with three distinct subspecies: the Nubian giraffe (G. c. camelopardalis), the West African giraffe (G. c. peralta) and the Kordofan giraffe (G. c. antiquorum)
The new Southern giraffe (Giraffa giraffa) becomes its own species, with two subspecies beneath it: the Angolan giraffe (G. g. angolensis) and the South African giraffe (G. g. giraffa).
The Masai giraffe (G. tippelskirchi) becomes a distinct species.
The Reticulated giraffe (G. reticulata) also is a new species.
The former subspecies Rothschild's giraffe (G. c. rothschildi) "disappears" in the Nubian giraffe subspecies, as the Rothschild's and the Nubian turned out to be genetic matches. Former subspecies the Thornicroft's giraffe (G. c. thornicrofti), meanwhile, appeared the same as the Masai giraffe (G. c. tippelskirchi).
Read more at Discovery News
The losses, reported in the journal Current Biology, are due to widespread human development and are equivalent to an area twice as big as Alaska and half the size of the Amazon. The study's authors call for immediate international policies to recognize the value of wilderness areas and to address the unprecedented threats these regions face.
"Globally important wilderness areas -- despite being strongholds for endangered biodiversity, for buffering and regulating local climates, and for supporting many of the world's most politically and economically marginalized communities -- are completely ignored in environmental policy," lead author James Watson of the University of Queensland and the Wildlife Conservation Society said in a press release.
"Without any policies to protect these areas, they are falling victim to widespread development," he continued. "We probably have one to two decades to turn this around. International policy mechanisms must recognize the actions needed to maintain wilderness areas before it is too late."
|An area is deforested to make way for a palm oil plantation in Indonesia.|
The comparison showed that 20 percent of the world's land area remains wilderness, the majority in North America, North Asia, North Africa and Australia. Ten percent of wilderness area was lost, however, during the intervening years. The losses occurred primarily in South America, which has experienced a 30 percent decline in wilderness, and in Africa, which has experienced a 14 percent loss.
"The amount of wilderness loss in just two decades is staggering," Oscar Venter, chair of the Ecosystem Science and Management Program at the University of Northern British Colombia, said.
"We need to recognize that wilderness areas, which we've foolishly considered to be de-facto protected due to their remoteness, are actually being dramatically lost around the world," Venter added. "You cannot restore wilderness, once it is gone, and the ecological process that underpin these ecosystems. The only option is to proactively protect what is left."
He, Watson and their colleagues believe that the United Nations and other international organizations have ignored globally significant wilderness areas in key multilateral environmental agreements.
"If we don't act soon, there will only be tiny remnants of wilderness around the planet, and this is a disaster for conservation, for climate change, and for some of the most vulnerable human communities on the planet," Watson said. "We have a duty to act for our children and their children."
From Discovery News
|Artist's impression of NASA's Osiris-Rex spacecraft on the job at Asteroid Bennu.|
Scientists hope their atomic-level analysis of the materials will shed light on why Earth -- and perhaps other planets in the solar system -- became habitats for life and perhaps even reveal the origins of life itself.
The asteroid, known as Bennu, dates back to the early days of the solar system's formation, said the mission's lead scientist Dante Lauretta, with the University of Arizona in Tucson.
"It's a time capsule … from back when our planetary system was spread across as dust grains in a swirling cloud around our growing protostar," Lauretta said.
Discovered in 1999 by Lincoln Near-Earth Asteroid Research (LINEAR) project, Bennu is a small, dark world just one-third of a mile in diameter that is orbiting the sun at roughly the same distance as Earth.
Bennu is among the thousands of so-called Near-Earth Asteroids, one or more of which may prove to be hazardous to Earth in the future. Scientists with the upcoming Osiris-Rex mission hope to learn more about how heating and pressure from sunlight impart motions into an asteroid. The information one day may be critical for diverting an asteroid that is on a collision course with Earth.
The $800 million Osiris-Rex spacecraft is expected to spend between 18 months and two years slowly circling Bennu so its science instruments and cameras can collect data for global, three-dimensional surface maps and catalog chemicals and minerals on the asteroid's surface.
Scientists expect to find Bennu rich with chondrules, which likely formed when bits of dust in the solar nebula were flash-heated to become molten rock that later solidified. Over time, chondrules clumped together to become the building blocks of asteroids and planets.
"On planets like Earth, the original materials have been profoundly altered by geologic activity and chemical reactions with our atmosphere and water. We think Bennu may be relatively unchanged," mission deputy scientist Edward Beshore, also with University of Arizona, said in a NASA interview.
Scientists suspect Bennu also contains organic material from the solar system's early years. Carbon-rich organics are key to life on Earth, and perhaps elsewhere as well.
NASA says an analysis of any organic material found on Bennu will give scientists an inventory of the materials present at the beginning of the solar system that may have had a role in the origin of life.
"By bringing this material back to Earth, we can do a far more thorough analysis than we can with instruments on a spacecraft, because of practical limits on the size, mass, and energy consumption of what can be flown," Beshore said.
Osiris-Rex is designed to collect a minimum of 60 grams – 2 ounces -- of soil and crushed rock from Bennu's surface. However, preflight tests of the probe's sample collection system have scientists optimistic the spacecraft can collect as much as 70 ounces, or 4 pounds.
Read more at Discovery News
Sep 7, 2016
Consisting of more than 180 lead bullets, the stash was found at Burnswark Hill near Lockerbie, in southwestern Scotland.
The site, rising to nearly 1,000 feet from the surrounding countryside, features on its flat-topped hill the remains of a 17-acre fort which experts believe originated in the Early Iron Age. Two Roman camps lie on the opposite sides of the fort.
For decades archaeologists have debated whether the Roman remains represent a siege or a training post. The 1,800-year-old sling bullets may help provide an answer.
"We have lemon-shaped sling bullets in the cache that are found in both Roman camps and on the hillfort," Andrew Nicholson, excavation director for the Burnswark Project, told Discovery News.
"However the large cache includes bullets of a globular shape, a type not thought to be in use until over a century later," he added.
Burnswark Hill in Britain has yielded a wide variety of Roman projectiles. Last year's dig revealed unusual lead bullets with circular holes drilled into them. It turned out they were meant to produce terrifying whistling noise in flight.
Although the large cache from the North Camp do not include any of such bullets, some more of those "terror weapons" were unearthed at the South Camp this year.
"We can now definitely link the sling bullets from both Roman camps with those found on the native hillfort," Nicholson said.
A lead or stone bullet could reach speeds of up to 100 mph when shot by expert slingers. The largest stones were the size of lemons, while the smallest were acorn-shaped and were slung in small groups of three or four as form of grapeshot.
Read more at Discovery News
|Flooding in Louisiana in August.|
The unprecedented 1 to 2 feet of rain that fell over parts of Baton Rouge and nearby communities over several days in the middle of August stunned experts. While such deluges are rare, the new research indicated that the likelihood the region will experience them may have doubled during the past century.
"This is a storm that's going to be studied for years to come," said Barry Keim, the Louisiana state climatologist and a professor at Louisiana State University. He was not involved with the study, which was published as a discussion paper Wednesday before being peer reviewed.
The findings were consistent with the general principle that global warming caused by greenhouse gas pollution from energy, farming and deforestation is increasing the risk and intensity of heavy storms worldwide.
The stubbornly slow-moving storm dumped more rain over the flood-prone region than its flood infrastructure could handle. At least one city, Central, home to 30,000 residents and 9,000 buildings that were flooded, is working to help property owners rebuild as quickly as possible, despite the rising risks that such floods could happen again.
"The odds of an event like this have increased over the past 100 years by at least 40 percent — and most likely a doubling," said Karin van der Wiel, a Princeton University and National Oceanic and Atmospheric Administration researcher who was involved with the study. She is based at the federal lab that conducted the analysis.
The study did not examine how infrastructure and urban planning in Louisiana affected flooding or its impacts. The research examined the role of climate change and natural variation in causing such heavy rains. Findings regarding the potential role that the strong recent El Niño played in the heavy rainfall were largely inconclusive.
"We set out to calculate the probability of having a precipitation event like this in the current climate, and compare that to the probability in the preindustrial climate," Van der Wiel said.
Van der Wiel and other researchers in New Jersey and the Netherlands analyzed two sets of weather data for the region. They also pored over the results of experiments that involved two computer models. Analysis of all four sources of information indicated that climate change is upping the risks of such devastating storms.
|Flooding around Baton Rouge in August.|
The group aims to help the public quickly understand links between climate change and individual instances of extreme weather. Its rapid attribution analyses have previously focused on droughts, heat waves and coral bleaching.
Scientists involved with the Louisiana study said the region's complex weather made their task more difficult than usual. It required the use of modeling experiments involving some of the world's most powerful climate models.
"This was absolutely the most challenging analysis we've done so far," said Heidi Cullen, Climate Central's chief scientist, and one of the authors of the new paper. Still, Cullen said she considered the findings "really robust."
National Center for Atmospheric Research senior scientist Kevin Trenberth, who was not involved with the study, said the findings provided a "partial commentary" on the storm. He said the work missed key details related to the roles of El Niño in the heavy rains.
"Extreme events always result from an intersection of natural variability of some sort riding on top of and enhancing global warming effects," Trenberth said. "This aspect was not addressed in this study."
The complexity of the new study "had a big impact on how certain we were" that "we would be able to do a sensible analysis," said Geert Jan van Oldenborgh, a Royal Netherlands Meteorological Institute climate scientist who was involved with this and prior rapid attribution studies.
Read more at Discovery News
As Trace Dominguez explains in today's DNews special report, a group of scientists recently published a very interesting report in the journal Geophysical Research Records. It appears that the researchers hijacked one of the supercomputer systems used to investigate climate change here on Earth -- and fed in a new set of input data.
The researchers wanted to know what life on Venus would be like if and when it had oceans on the surface. We can't know for sure, but many astrobiologists contend that Venus once had water, and probably had life. After all, the planet has an orbit that's very similar to ours, and it sits just inside the inner edge of solar system's habitable zone.
It's clear that Venus is not capable of supporting life now -- at least, not life as we know it. Something catastrophic happened to Venus' atmosphere in the last few hundred million years and atmospheric pressure there is about 90 times greater than on Earth. It's also a twinge on the hot side. Average temperature is upwards of 800 degrees Fahrenheit.
However, a few billion years ago our sun wasn't as hot as it is now, so it's entirely possible that liquid water could have existed on Venus. What's more, according to the computer simulations, that water would have had the effect of regulating atmospheric temperatures by creating a kind of planetary parasol of clouds.
In fact, even if Venus had only 10 percent of the water volume of Earth's oceans, the planet could have conceivably maintained an Earth-like environment for billions of years. And when you combine habitable temperatures with liquid water and billions of years, you get the possibility of the evolution of life.
Alas, we may never know for sure. Venus is a tricky place to study up close, what with those temperatures and that atmospheric pressure. The Soviets actually managed to drop a few landers on Venus in the 1970s, but they burned up within a couple of hours.
Double Secret Bonus Ordnance Trivia: When Earth obstructed his view of Venus, Marvin the Martian attempted to blow us all up with an illudium Q-36 explosive space modulator.
From Discovery News
Mysterious lights in the sky are of course as old as antiquity and come in many forms, ranging from meteors to UFOs. Lights such as those seen in the Upper Peninsula are often referred to as ghost lights or spook lights.
These lights are not merely encountered as factual, visible anomalies but instead often appear in the context of ghost stories. Local folklore provides a legendary "explanation" for the lights, part of a long tradition of creating narratives to explain natural celestial processes (Greek mythology held that the sun was not a stationary dying star, but instead the god Helios driving his golden chariot around the Earth).
Some traditions link floating lights with death, accounts from centuries ago suggest that if a person saw three distinct unknown lights in the sky, it was an omen that three deaths should be expected soon. Though such superstitions are rarer today, the association between mysterious lights and ghosts or the supernatural lives on in folklore.
Fans explore and post videos of their experience, speculating endlessly about the light's origin. In the case of the Paulding Light, John Carlisle of The Detroit Free Press explains that a half-century old "legend says the light comes from the swaying lantern held by the ghost of a railroad brakeman who died when he was crushed as he tried to stop an oncoming train from hitting railcars stalled on the tracks.
This was logging country more than a century ago, and local residents say there were a number of railroads that ran through the forest and are now buried in the underbrush. Some believe it's the light of the train, which itself is now a ghost. Some claim it's the distraught spirit of a grandparent looking for a lost grandchild with a lantern that needs constant relighting, the reason the light seems to come and go."
Other places with similar reports include the Brown Mountain Lights of North Carolina, Missouri's Ozark Spooklight, and the Marfa lights in Texas. There are many natural explanations for curious lights seen in the skies, and a single blanket explanation cannot account for them all. Instead, it depends on the specific circumstances of each location: some areas may contain groups of bioluminescent animals, including fireflies (which are in fact beetles); other locations may have types of fungus that emit light.
The phenomenon of St. Elmo's Fire -- glowing lights seen at the tops of ships and airplane wings -- can be created by an electrical discharge, especially during rough weather. Other explanations include aircraft lights, reflections from stars or planets distorted through layers of different temperatures and will-o-the-wisp, glowing swamp gas seen over marshes and wetland caused by the oxidation of decomposing organic matter.
The lights are only seen under certain conditions and circumstances. Many visitors wait in vain for hours and see nothing. Eyewitnesses to the same phenomena sometimes offer different descriptions of what they saw. Some are said to briefly flicker in place. Others are said to dance or shoot across the sky like a UFO. The lights are often faint and may be influenced by imagination and misperception -- if not liquor.
Solving the Mystery
The distant lights' fickle nature make them difficult to fully investigate. Members of the show SyFy television show "Fact or Faked: Paranormal Files" tackled the Paulding Light case but failed to solve the mystery. Others, however, succeeded. As Carlisle noted, "a few years ago ... a group of engineering students from a nearby university conducted experiments at the viewing site and claimed to have solved the mystery once and for all, in a fairly unexciting way."
In 2010, a team from Michigan Tech led by electrical engineering student Jeremy Bos "brought a spectrograph and a telescope to the dead-end road, sent each other driving down the new highway while blinking their lights in a prearranged pattern, and recorded the results. Every time the light appeared, one look through the telescope showed what sure looked like the headlights of oncoming cars, which could be seen clearly through the lens, sometimes with the distinct outline of the car coming down the road, which is about 8 miles away. The group even shot a video through the telescope so others could see, and posted it online. The flickering, they said, was caused when cars went over a hill."
Read more at Discovery News
Officials from the International Union for Conservation of Nature (IUCN) announced Sunday (Sept. 4) that they're raising the threatened status of the Grauer's gorilla from "endangered" to "critically endangered," the highest category before extinction.
"Critical endangered status will raise the profile of this gorilla subspecies and bring attention to its plight," Andrew Plumptre, the lead author of the new listing, said in a statement. "It has tended to be the neglected ape in Africa, despite being the largest ape in the world."
Grauer's gorillas (Gorilla beringei graueri) are a subspecies of the eastern gorilla. They are found in fragmented forest habitats in the eastern part of the Democratic Republic of Congo, where they mainly subsist on fruit and other plants and can grow up to 5.5 feet (168 cm) tall and weigh up to 440 lbs. (200 kg).
Earlier this year, the Wildlife Conservation Society and Fauna and Flora International released a report documenting a77-percent drop in the number of Grauer's gorillas over the span of a single generation, from an estimated 17,000 individuals in 1995 to 3,800 today.
The authors of the report pointed to bushmeat hunting and civil war in the DRC as major drivers of the population collapse and recommended that the species be listed as critically endangered.
The new listing means that all gorillas —including eastern and western gorillas —are now considered critically endangered.
The other subspecies of the eastern gorilla is the mountain gorilla (Gorilla beringei beringei), which is already listed as critically endangered. The population of mountain gorillas has, however, been increasing. There are now an estimated 880 individuals, up from about 300 in 2008, according to the IUCN's latest data.
The changes to the IUCN's Red List of Threatened Species were announced at the organization's World Conservation Congress in Hawaii.
Read more at Discovery News
Sep 6, 2016
A quarry in Strud, Belgium, that was excavated between 2004 and 2015 yielded fossils of multiple species of placoderms, which are extinct, armored fish that represent some of the earliest jawed vertebrates on Earth. Dating back to the Devonian period, an era predating the dinosaurs by hundreds of millions of years, the site yielded smaller-sized fossils that show immature placoderms occupied the area. At the same time, larger placoderm fossils, indicating mature fish, were not found.
"These sorts of juvenile-only assemblages are rare in the fossil record," said Ted Daeschler, PhD, vice president of the Academy of Natural Sciences of Drexel University, who served as a co-author on the study published in PLOS ONE. "We are quite sure that the juvenile-only placoderm assemblage is not the result of sorting of small material by water currents because there are larger skeletal elements of other kinds of fish. We believe this points to a nursery."
The study was led by Sébastien Olive, a vertebrate paleontologist in the Royal Belgian Institute of Natural Sciences who is now on a post-doctoral fellowship at the Academy of Natural Sciences of Drexel University. By studying a site like Strud, Olive feels it will help give a more complete picture of ancient life.
"Reconstructing life histories of extinct organisms is a rare opportunity to go beyond simply describing the anatomy of ancient life," Olive said. "With these sorts of records, we can actually begin to understand aspects of behavior and life history of organisms that went extinct hundreds of millions of years ago."
The Strud site, which dates to the late part of the Devonian period (more than 360 million years ago), features many pieces of immature fish skeletons that were largely intact despite being small and fragile. As such, this pointed toward slow-moving and shallow water. An environment like that would have been -- and remains, for present-day fish -- ideal for the development of the young.
"Adult placoderms may have used the nursery of Strud only to lay eggs and/or give live birth, and would have generally lived away from the nursery in deeper waters," wrote the research team, which also included paleontologists Gaël Clément of the Museum national d'Histoire Naturelle in Paris, and Vincent Dupret, of Uppsala University in Sweden.
An added benefit of the nursery site would have been its protection from predators, thanks to the "large, hard and sometimes spiny" vegetation that was found fossilized on-site.
While the find at Strud is now one of the oldest-known nurseries in the world, similar records exist in Pennsylvania, especially at a site called Red Hill. During the Devonian period, the Pennsylvania and Strud sites would have been relatively close to each other since the Atlantic Ocean hadn't begun to open to separate them. Daeschler and Olive's work focused largely on comparing the Red Hill site to Strud, noting many similarities between the two and using the size and shape of placoderm fossils from Red Hill, housed at the Academy of Natural Sciences, to establish the relative maturity of samples found in Strud.
With three different types of placoderm fossils discovered at Strud -- Grossilepis rikiki, Turrisaspis strudensis and Phyllolepis undulata -- it opens a question for scientists like Daeschler.
"This is the first time that it can be demonstrated that several species seem to have used a common nursery," Daeschler said. "It makes us wonder: Has that always been a common reproductive strategy?"
Although placoderms are long extinct, getting glimpses of their lives puts more pieces together in the evolutionary puzzle.
"In the case of placoderms like these, we're looking at some of the earliest jawed vertebrates," Olive said. "Understanding their life history can give us an idea of the primitive condition from which all other jawed vertebrates evolved."
Read more at Science Daily
In an interview with Oregon TV station KATU, David Kalas, who shot the video, said the vandals told him that they destroyed the formation because a friend of theirs had broken his leg on it. Oregon State Police and state parks officials told the Portland Oregonian that they were reviewing the video, and that the perpetrators might face criminal charges in addition to citations and fines.
But the destruction of the iconic rock highlights an even bigger problem. Many comparable natural formations in parks across the nation are similarly fragile and vulnerable to human visitors who, for whatever reasons, decide to destroy them.
Back in 2013, for example, two men knocked over the Goblins, a 20-million-year-old formation at Goblin Valley State Park in Utah, because they thought it was dangerous to hikers. They eventually pleaded guilty to misdemeanor criminal charges and received probation and fines.
Other formations have been marred by graffiti artists. In June, a woman who pled guilty to defiling rock formations at seven national parks was banned from all 524 million acres of U.S. public lands and sentenced to 200 hours of community service, according to the Los Angeles Times.
Not all people who destroy rock formations are doing it intentionally. Mushroom Rock in California's Death Valley, seen below, is an example of a rock formation that's deteriorated badly over the years due to visitors climbing on it to take pictures.
|Analysis of a ship carpenter's remains showed that he was a muscular man of about 5 feet 7 inches tall in his mid- to late-thirties. His dental health was poor and an abscess in his jaw left him able to chew only on his right side.|
One skull, reproduced in a fully interactive model, belonged to a carpenter on board the Mary Rose, the flagship of England's navy when it sank in 1545 as heartbroken Henry VIII watched from the shore.
"An abscess in his upper jaw meant he could only chew on the right side," said details on the website, www.virtualtudors.org. "He also had arthritis in his spine, ribs and left clavicle and a lesion across his right eyebrow which may be the result of an old wound."
|More than 280 intact leather shoes were found during the Mary Rose excavation, This one was found near the body of the carpenter.|
The technique is known as photogrammetry, using high-resolution 2D photographs to produce detailed 3D models.
"This digital resource enables researchers around the world to join the project and study virtual 3D reconstructions," said professor Catherine Fletcher.
"Once fully developed, this technology can be applied to many more historic objects, bringing them to an even wider community of researchers while preventing damage to the original remains and artifacts."
The researchers captured 1,000 images of 10 skulls found on the ship to create navigable online models, which they hope other researchers will analyse to eventually recreate full skeletons of some of the 500 men who perished.
The Mary Rose fought three wars with the French but mysteriously keeled over and sank off Portsmouth on July 19, 1545, while fighting off a French invasion fleet.
|This small octagonal mirror made of beech wood was one of only two found. Traces of corrosion and a white substance may be the remains of the mirror and fixative.|
The public can view a sample of the objects such as a mirror, rigging or a leather shoe on the Virtual Tudors website—a collaboration between Swansea University, the Mary Rose Trust and Oxford University.
Read more at Discovery News
"You have to have a pretty decent telescope to see it. It's just a dot of light but it's a very special dot of light, and maybe one day we'll get there," May said in the video.
The asteroid, previously known as Asteroid 17473, is about 2 miles in diameter and orbits in the main asteroid belt between Mars and Jupiter.
The asteroid's new designation was made by the International Astronomical Union's Minor Planet Center, located at the Smithsonian Astrophysical Observatory in Cambridge, Mass.
The asteroid was discovered in 1991 and was renamed on Sunday, Sept. 4, which would have been Mercury's 70th birthday. Word of the asteroid's new name was reported on Tuesday in The New York Times.
The improvement for the giant panda (Ailuropoda melanoleuca) was announced as part of an update to the International Union for Conservation of Nature (IUCN) Red List, the world's most comprehensive inventory of plants and animals.
The latest estimates show a population of 1,864 adult giant pandas. Although exact numbers are not available, adding cubs to the projection would mean about 2,060 pandas exist today, said the IUCN.
"Evidence from a series of range-wide national surveys indicate that the previous population decline has been arrested, and the population has started to increase," said the IUCN's updated report.
The cornerstones of the Chinese government's effort to bring back its fuzzy, black-and-white national icon have included an intense effort to replant bamboo forests, which provide food and shelter for the bears.
Through its "rent-a-panda" captive breeding program, China has also loaned some bears to zoos abroad in exchange for cash, and reinvested that money in conservation efforts.
"When push comes to shove, the Chinese have done a really good job with pandas," John Robinson, a primatologist and chief conservation officer at the Wildlife Conservation Society, told AFP.
"So few species are actually downlisted, it really is a reflection of the success of conservation," he said at the IUCN World Conservation Congress, the largest meeting of its kind, which drew more than 9,000 heads of state, policymakers and environmentalists to Honolulu.
According to Simon Stuart, chair of the IUCN Species Survival Commission, the improvement was "not rocket science" but came from the hard work of controlling poaching and replanting bamboo forests.
"This is something to celebrate because it is not a part of the world where we expect this to happen," Stuart told reporters at a press conference to unveil the updated Red List.
Experts warned, however, that the good news for pandas could be short-lived.
A warming planet, driven by fossil fuel burning, is predicted to wipe out more than one-third of the panda's bamboo habitat in the next 80 years.
Read more at Discovery News
Sep 5, 2016
|Group A Strep M protein (seen at center as golden helices) surrounded by two molecules of human C4BP in blue.|
In a paper published in this week's issue of Nature Microbiology, the researchers report that they had uncovered "hidden sequence patterns in the major surface protein and virulence factor" of group A Strep, called the M protein, that limit the body's immune response against these bacteria.
"At present, there is no vaccine against group A Strep, and our discovery of hidden sequence patterns has offered up a novel way to devise such a vaccine," said Partho Ghosh, chair of UC San Diego's Department of Chemistry and Biochemistry, who headed the team of researchers.
Ghosh said that one of the biggest obstacles to the development of a vaccine against these bacteria is the "hyper-variability" of the M protein. Group A Streptococcus bacteria have a multitude of different strains, each of which displays a different protein on its surface. Because our immune systems must recognize these different proteins before launching an immune response with antibodies specific to the outer protein coat, the hyper-variability of the M proteins make it difficult for our immune systems to attach antibodies specific to each these proteins from different strains.
"When we become infected with a particular strain of group A Strep, we generally mount an immune response against the particular M protein displayed by that strain," explains Ghosh. "But this immunity works only against the infecting strain. We remain vulnerable to infection by other group A Strep strains that display other types of M proteins on their surfaces. This is because the antibody response against the M protein is almost always specific to the sequence of that M protein, and M proteins of different types appear to be unrelated in sequence to one another."
The key to resolving the problem was the recognition that a human protein called C4BP had been discovered by another group of researchers to be recruited to the surface of Group A Strep by many different protein types.
"This was a puzzle, because the antibody response is specific and limited to a single M protein type, while C4BP binds a broad variety of M protein types, perhaps up to 90 percent of them," said Ghosh. "Group A Strep brings C4BP to its surface to dampen the immune response. We wanted to combat this recruitment by blocking the interaction between M proteins and C4BP, but equally as importantly, we wanted to take advantage of the broad recruitment of C4BP by M proteins that would pave a path to the development of a vaccine."
To determine if this was possible, a graduate student in Ghosh's lab, Cosmo Buffalo, collaborated with another graduate student, Sophia Hirakis, in the laboratory of Rommie Amaro, a professor of chemistry and biochemistry who uses computers to study protein structures, to first study the complex interactions between M protein and C4BP.
"This allowed us to understand some detailed features of the interaction," said Ghosh. The research team, which also included an undergraduate researcher, Adrian Bahn-Suh, collaborated extensively with Victor Nizet, an expert in infectious diseases who is a professor at UC San Diego's School of Medicine and Skaggs School of Pharmacy and Pharmaceutical Sciences.
In their experimental and computational study, the biochemists painstakingly detailed four crystal structures of four different M protein types, each bound to human C4BP.
"These structures revealed that even though the different M protein types appeared to be unrelated in sequence, there were common sequence patterns hidden within the differences that linked all these M proteins together," said Ghosh. "These common patterns are what is used to recruit C4BP to the surface of group A Strep by the different M protein types."
"The idea now is to have antibodies do the same thing as C4BP -- that is, recognize many different M protein types," he added. "That way, the antibody response will not be limited to one M protein type and one strain of group A Strep, but will extend to most, if not all, M protein types and most, if not all strains, of group A Strep."
Read more at Science Daily
|This simulation shows how two galaxies merge over a period of 15 million years. The red and the blue dots illustrate the two black holes.|
In his General Theory of Relativity, Albert Einstein predicted gravitational waves over a century ago; this year, they were detected directly for the first time: The American Gravitational Wave Observatory LIGO recorded such curvatures in space from Earth, which were caused by the merging of two massive black holes. And the research on gravitational waves -- and thus the origin of the universe -- continues: From 2034 three satellites are to be launched into space in a project headed by the European Space Agency (ESA) to measure gravitational waves at even lower frequency ranges from space using the Evolved Laser Interferometer Space Antenna (eLISA).
Until now, however, it was not possible to conclusively predict the point at which gravitational waves are triggered and spread throughout space when galaxies merge. An international team of astrophysicists from the University of Zurich, the Institute of Space Technology Islamabad, the University of Heidelberg and the Chinese Academy of Sciences has now calculated this for the first time using an extensive simulation.
Much faster than previously assumed
Every galaxy has a supermassive black hole at its core, which can exhibit millions or even billions of solar masses. In a realistic simulation of the universe, the merging of two roughly 3-billion-year-old galaxies lying relatively close to one another was simulated. With the aid of supercomputers, the researchers calculated the time the two central black holes with around 100 million solar masses needed to emit strong gravitational waves after the galaxies collided.
"The result is surprising," explains Lucio Mayer from the Institute for Computational Science of the University of Zurich: "The merging of the two black holes already triggered the first gravitational waves after 10 million years -- around 100 times faster than previously assumed."
Year-long supercomputer calculation
The computer simulation, which took more than a year, was conducted in China, Zurich and Heidelberg. The project required an innovative computational approach with various numerical codes on different supercomputers. In the process, each supercomputer was responsible for calculating a certain phase of the orbital convergence of the two massive black holes and their parent galaxies.
Read more at Science Daily
|Best known for an enormous eruption in the 1840s that created the billowing, hourglass-shaped Homunculus nebula imaged here by the Hubble Space Telescope, Eta Carinae is the most massive and luminous star system within 10,000 light-years.|
What had happened to cause this outburst? Did 19th-century astronomers witness some strange type of supernova, a star ending its life in a cataclysmic explosion?
"Not quite," says Megan Kiminki, a doctoral student in the University of Arizona's Department of Astronomy and Steward Observatory. "Eta Carinae is what we call a supernova impostor. The star became very bright as it blew off a lot of material, but it was still there."
Indeed, in the mid-20th century Eta Carinae began to brighten again.
The aftermath of the "Great Eruption" of the mid-1800s, which is now readily visible through a small telescope if you happen to be in the Southern Hemisphere, made Eta Carinae a celebrity among objects in the universe known for their bizarre beauty. An hourglass-shaped, billowing cloud of glowing gas and dust enshrouds the star and its companion. Known as the Homunculus nebula, the cloud consists of stellar material hurled into space during the Great Eruption, drifting away at 2 million miles per hour.
By carefully analyzing images of Eta Carinae taken with NASA's Hubble Space Telescope, Kiminki and her team were surprised to discover that the Great Eruption was only the latest in a series of massive outbursts launched by the star system since the 13th century. Published in the journal Monthly Notices of the Royal Astronomical Society, the paper was co-authored by Nathan Smith, associate professor in the UA's Department of Astronomy, and Megan Reiter, who obtained her Ph.D. from the same department last year and is now a postdoctoral fellow at the University of Michigan.
The expansion rate of gas that was far outside the Homunculus indicated that it was moving slowly and must have been ejected centuries before the observed 19th-century brightening. In fact, the motions of the outer material point to two separate eruptions in the mid-13th and mid-16th centuries.
For scientists trying to piece together what makes star systems such as Eta Carinae tick, the findings are like the stereotypical smoking gun in a detective story.
"From the first reports of its 19th-century outburst up to the most recent data obtained with advanced capabilities on modern telescopes, Eta Carinae continues to baffle us," Smith says. "The most important unsolved problem has always been the underlying cause of its eruption, and now we find that there were multiple previous eruptions. This is a bit like reconstructing the eruption history of a volcano by discovering ancient lava flows."
Although the glowing gases of the Homunculus nebula prevent astronomers from getting a clear look at what's inside, they have figured out that Eta Carinae is a binary system of two very massive stars that orbit each other every 5.5 years. Both are much bigger than our sun and at least one of them is nearing the end of its life.
"These are very large stars that appear very volatile, even when they're not blowing off nebulae," Kiminki says. "They have a dense core and very fluffy envelopes. If you replaced our sun by the larger of the two, which has about 90-100 solar masses, it could very well extend into the orbit of Mars."
Because the Homunculus nebula is such an iconic and visually stunning object, it has been a popular target of astronomical observations. A total of eight images, taken over the course of two decades with Hubble, turned out to be a treasure trove for Kiminki and her co-authors.
The original goal of the team's observing program was to measure proper motions of stars and protostellar jets -- fast streams of matter ejected by young stars during formation -- in the Carina Nebula, but the same data also provided a powerful way to measure the motion of debris ejected by Eta Carinae itself.
"As I was aligning the images, I noticed that the one that Eta Carinae in it was more difficult to align," Kiminki says. "We can only use objects as alignment points that aren't moving, and I thought, 'Wow, a lot of this stuff is really moving.' And then we decided to take a closer look."
By aligning the multi-epoch images of the nebula, the team was able to track the movement of more than 800 blobs of gas Eta Carinae had ejected over time and derived a likely ejection date for each. The analyses showed that the Homunculus nebula and the observed 19th-century brightening tell only part of the story. Measuring the speed with which wisps of ejected material expand outward into space revealed that they must have resulted from two separate eruptions that occurred about 600 and 300 years before the Great Eruption of the 19th century.
In addition to having a separate origin in time, the older material also showed a very different geometry from the Homunculus, where material was ejected out from the star's poles and appears symmetric about its rotation axis.
"We found one of the prior eruptions was similarly symmetric, but at a totally different angle from the axis of the Great Eruption," Kiminki explains. "Even more surprising was that the oldest eruption was very one-sided, suggesting two stars were involved, because it would be very unlikely for one star to blow material out toward just one side."
Though perplexing, the findings are a big step forward for astronomers trying to understand what causes the frequent outbursts.
"We don't really know what's going on with Eta Carinae," Kiminki says. "But knowing that Eta Carinae erupted at least three times tells us that whatever causes those eruptions must be a recurring process, because it wouldn't be very likely that each eruption is caused by a different mechanism."
"Even though we still have not figured out the underlying physical mechanism that caused the 19th-century eruption, we now know that it isn't a one-time event," Smith says. "That makes it harder to understand, but it is also a critical piece of the puzzle of how very massive stars die. Stars like Eta Carinae apparently refuse to go quietly into the night."
Read more at Science Daily
The remains of the Storr Lochs Monster now comprise the most complete skeleton of a sea-living reptile from the Age of Dinosaurs that has ever been discovered in Scotland, according to Steve Brusatte of the University of Edinburgh and his colleagues. The scientists say that its fossils were originally found on the Isle of Skye by Norrie Gillies, the then manager of the SSE Storr Lochs Power Station who has since died at age 93.
The Storr Lochs Monster has been identified as an ichthyosaur. These were a family of now-extinct marine reptiles that thrived in prehistoric seas at the same time that dinosaurs dominated terrestrial ecosystems.
"Ichthyosaurs like the Storr Lochs Monster ruled the waves while dinosaurs thundered across the land," Brusatte said in a press release. "Their bones are exceptionally rare in Scotland, which makes this specimen one of the crown jewels of Scottish fossils. It's all thanks to the keen eye of an amateur collector that this remarkable fossil was ever found in the first place, which goes to show that you don't need an advanced degree to make huge scientific discoveries."
The researchers -- due to a partnership between the University of Edinburgh, National Museums Scotland and the energy company SSE -- were able to extract the ichthyosaur's remains from the rock that encased it for millions of years.
The fossils show that the over 13-feet-long Storr Lochs Monster was an especially toothy ichthyosaur that lived around 170 million years ago. When alive, it would use its pointed head filled with hundreds of cone-shaped teeth to feast on fish and squid, and probably almost anything else that had the misfortune of coming into its way.
Further research may reveal how ichthyosaurs evolved during the Middle Jurassic Period (176 to 161 million years ago), a part of Earth's history that has long been shrouded in mystery owing to a lack of fossil evidence. The Isle of Skye, which is connected to Scotland's northwest coast by bridge, is one of the few places in the world where fossils from this period can be found.
Nick Fraser of National Museums Scotland's natural sciences division said, "The Storr Lochs Monster highlights the rich fossil heritage of Skye."
SSE's Michael Pibworth hopes that the Storr Lochs Monster "will indeed prove to be a 'crown jewel' in Scotland's Jurassic history and thanks to the foresight of the Gillies family, enjoyed by generations to come."
From Discovery News
Sep 4, 2016
With the multitude of stars and galaxies that populate the present Universe, it's hard to imagine how different our 13.8 billion year cosmos was when it was only a few seconds old. At that early phase, it was a hot, dense primordial soup of particles, mostly electrons, protons, neutrinos, and photons -- the particles of light.
In such a dense environment the Universe appeared like an 'opaque' fog, as light particles could not travel any significant distance before colliding with electrons.
As the cosmos expanded, the Universe grew cooler and more rarefied and, after about 380,000 years, finally became 'transparent'. By then, particle collisions were extremely sporadic and photons could travel freely across the cosmos.
Today, telescopes like Planck can observe this fossil light across the entire sky as the Cosmic Microwave Background, or CMB. Its distribution on the sky reveals tiny fluctuations that contain a wealth of information about the history, composition and geometry of the Universe.
The release of the CMB happened at the time when electrons and protons joined to form hydrogen atoms. This is the first moment in the history of the cosmos when matter was in an electrically neutral state.
After that, a few hundred million years passed before these atoms could assemble and eventually give rise to the Universe's first generation of stars.
As these first stars came to life, they filled their surroundings with light, which subsequently split neutral atoms apart, turning them back into their constituent particles: electrons and protons. Scientists refer to this as the 'epoch of reionisation'. It did not take long for most material in the Universe to become completely ionised, and -- except in a very few, isolated places -- it has been like that ever since.
Observations of very distant galaxies hosting supermassive black holes indicate that the Universe had been completely reionised by the time it was about 900 million years old. The starting point of this process, however, is much harder to determine and has been a hotly debated topic in recent years.
"The CMB can tell us when the epoch of reionisation started and, in turn, when the first stars formed in the Universe," explains Jan Tauber, Planck project scientist at ESA.
To make this measurement, scientists exploit the fact that a fraction of the CMB is polarised: part of the light vibrates in a preferred direction. This results from CMB photons bouncing off electrons -- something that happened very frequently in the primordial soup, before the CMB was released, and then again later, after reionisation, when light from the first stars brought free electrons back onto the cosmic stage.
"It is in the tiny fluctuations of the CMB polarisation that we can see the influence of the reionisation process and deduce when it began," adds Tauber.
A first estimate of the epoch of reionisation came in 2003 from NASA's Wilkinson Microwave Anisotropy Probe (WMAP), suggesting that this process might have started early in cosmic history, when the Universe was only a couple of hundred million years old. This result was problematic, because there is no evidence that any stars had formed by then, which would mean postulating the existence of other, exotic sources that could have caused the reionisation at that time.
This first estimate was soon to be corrected, as subsequent data from WMAP pushed the starting time to later epochs, indicating that the Universe had not been significantly reionised until at least some 450 million years into its history.
This eased, but did not completely solve the puzzle: although the earliest of the first stars have been observed to be present already when the Universe was 300 to 400 million years old, it remained unclear whether these stars were the main culprits for reionising fully the cosmos or whether additional, more exotic sources must have played a role too.
In 2015, the Planck Collaboration provided new data to tackle the problem, moving the reionisation epoch even later in cosmic history and revealing that this process was about half-way through when the Universe was around 550 million years old. The result was based on Planck's first all-sky maps of the CMB polarisation, obtained with its Low-Frequency Instrument (LFI).
Now, a new analysis of data from Planck's other detector, the High-Frequency Instrument (HFI), which is more sensitive to this phenomenon than any other so far, shows that reionisation started even later -- much later than any previous data have suggested.
"The highly sensitive measurements from HFI have clearly demonstrated that reionisation was a very quick process, starting fairly late in cosmic history and having half-reionised the Universe by the time it was about 700 million years old," says Jean-Loup Puget from Institut d'Astrophysique Spatiale in Orsay, France, principal investigator of Planck's HFI.
"These results are now helping us to model the beginning of the reionisation phase."
"We have also confirmed that no other agents are needed, besides the first stars, to reionise the Universe," adds Matthieu Tristram, a Planck Collaboration scientist at Laboratoire de l'Accélérateur Linéaire in Orsay, France.
The new study locates the formation of the first stars much later than previously thought on the cosmic timeline, suggesting that the first generation of galaxies are well within the observational reach of future astronomical facilities, and possibly even some current ones.
Read more at Science Daily