Baby star's fiery tantrum could create the building blocks of planets

Artist’s impression of a similar solar flare (a very large flare from EV Lac) available via the NASA website, use only with Image

A massive stellar flare on a baby star has been spotted by University of Warwick astronomers, shedding light on the origins of potentially habitable exoplanets.

One of the largest ever seen on a star of its type, the huge explosion of energy and plasma is around 10,000 times bigger than the largest solar flare ever recorded from our own Sun.

The discovery is detailed in a paper for the Monthly Notices of the Royal Astronomical Society and reveals how this huge 'tantrum' could even perturb the material orbiting a star which would create the building blocks for future planets.

The flare was seen on a young M-type star named NGTS J121939.5-355557, located 685 light years away. At around 2 million years old, it is what astronomers refer to as a pre-main sequence star which is yet to reach the size that it spends the majority of its lifecycle.

It was observed as part of a large flare survey of thousands of stars by University of Warwick PhD student James Jackman, as part of a project searching for explosive phenomena on stars outside our solar system. He used the Warwick-led Next-Generation Transit Survey (NGTS) telescope array in Chile which is designed to find exoplanets by collecting brightness measurements of hundreds of thousands of stars and is based at the European Southern Observatory's Paranal Observatory. His attention was drawn to NGTS J121939.5-355557 as it had one of the largest flares seen in these types of stars.

A stellar flare occurs when the magnetic field of a star rearranges itself, releasing huge amounts of energy in the process. This accelerates charged particles, or plasma, within the star which crash into its surface, heating it up to around 10,000 degrees. That energy produces optical and infra-red light, but also x-rays and gamma rays that can be picked up by telescopes on Earth and in orbit.

Magnetic fields on M stars are a lot stronger than those on our own sun and the astronomers calculated that this size of flare is a rare event, occurring anywhere from every three years to twice a decade.

James, who is studying in the University of Warwick's Department of Physics, said: "This is normally a star that shows little activity and stays a constant brightness. Then, on this one particular night, we saw it suddenly grow seven times brighter than normal for a few hours, which is pretty extreme. And then after that it goes back to normal.

"We see these types of flares on the Sun, but no-where near as big as this. On our Sun, you can do incredibly detailed studies on this kind of activity. It's difficult to extend that understanding to other stars because the data we need hasn't been available until now.

"This is an incredibly young star, only about 2 million years old. You'd call it a baby -- it's going to live for ten of billions of years, so it's in the first one percent of its lifetime. Even though it's much cooler than our Sun by about 2000 degrees it is roughly the same size, but pretty large for an M star. This is because it's still being formed from gas in the disc and contracting and cooling until it reaches the main sequence, staying at a certain radius and luminosity for billions of years.

"Finding out these kinds of details has only been possible thanks to the Gaia mission that began earlier this year."

The X-rays from these large flare events are thought to affect the formation of 'chondrules', flash-melted calcium-aluminium-rich grains in the star's protoplanetary disc. These gather together into asteroids that eventually coalesce into orbiting planets. The study adds to our understanding of how flares 'perturb' the protoplanetary disc, moving around the material that impacts on planet formation and affecting the eventual structure of a planetary system.

Professor Peter Wheatley, James's PhD supervisor, said: "A massive flare like this could be advantageous for planet formation, or it could be disruptive. This particular star won't have formed its planets yet so this type of flare activity is something that astronomers will need to take into account when considering planet formation.

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3D-printed robot hand plays the piano

Robot hand playing the piano.

Scientists have developed a 3D-printed robotic hand which can play simple musical phrases on the piano by just moving its wrist. And while the robot is no virtuoso, it demonstrates just how challenging it is to replicate all the abilities of a human hand, and how much complex movement can still be achieved through design.

The robot hand, developed by researchers at the University of Cambridge, was made by 3D-printing soft and rigid materials together to replicate of all the bones and ligaments -- but not the muscles or tendons -- in a human hand. Even though this limited the robot hand's range of motion compared to a human hand, the researchers found that a surprisingly wide range of movement was still possible by relying on the hand's mechanical design.

Using this 'passive' movement -- in which the fingers cannot move independently -- the robot was able to mimic different styles of piano playing without changing the material or mechanical properties of the hand. The results, reported in the journal Science Robotics, could help inform the design of robots that are capable of more natural movement with minimal energy use.

Complex movement in animals and machines results from the interplay between the brain (or controller), the environment and the mechanical body. The mechanical properties and design of systems are important for intelligent functioning, and help both animals and machines to move in complex ways without expending unnecessary amounts of energy.

"We can use passivity to achieve a wide range of movement in robots: walking, swimming or flying, for example," said Josie Hughes from Cambridge's Department of Engineering, the paper's first author. "Smart mechanical design enables us to achieve the maximum range of movement with minimal control costs: we wanted to see just how much movement we could get with mechanics alone."

Over the past several years, soft components have begun to be integrated into robotics design thanks to advances in 3D printing techniques, which has allowed researchers to add complexity to these passive systems.

The human hand is incredibly complex, and recreating all of its dexterity and adaptability in a robot is a massive research challenge. Most of today's advanced robots are not capable of manipulation tasks which small children can perform with ease.

"The basic motivation of this project is to understand embodied intelligence, that is, the intelligence in our mechanical body," said Dr Fumiya Iida, who led the research. "Our bodies consist of smart mechanical designs such as bones, ligaments, and skins that help us behave intelligently even without active brain-led control. By using the state-of-the-art 3D printing technology to print human-like soft hands, we are now able to explore the importance of physical designs, in isolation from active control, which is impossible to do with human piano players as the brain cannot be 'switched off' like our robot."

"Piano playing is an ideal test for these passive systems, as it's a complex and nuanced challenge requiring a significant range of behaviours in order to achieve different playing styles," said Hughes.

The robot was 'taught' to play by considering how the mechanics, material properties, environment and wrist actuation all affect the dynamic model of the hand. By actuating the wrist, it is possible to choose how the hand interacts with the piano, allowing the embodied intelligence of the hand to determine how it interacts with the environment.

The researchers programmed the robot to play a number of short musical phrases with clipped (staccato) or smooth (legato) notes, achieved through the movement of the wrist. "It's just the basics at this point, but even with this single movement, we can still get quite complex and nuanced behaviour," said Hughes.

Despite the limitations of the robot hand, the researchers say their approach will drive further research into the underlying principles of skeletal dynamics to achieve complex movement tasks, as well as learning where the limitations for passive movement systems lie.

"This approach to mechanical design can change how we build robotics," said Iida. "The fabrication approach allows us to design mechanically intelligent structures in a way that is highly scalable."

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More young and other traits help mammals adapt to urban environments

Species of mammals that live in urban environments produce more young compared to other mammals. But next to this common 'winning trait', mammals deal with different strategies to successfully inhabit cities. This is what Radboud University ecologist Luca Santini and colleagues found in a study that they will publish in Ecology Letters on 21 December. "This is the first step of many to understand why certain mammals manage to live in cities and why other species don't."

Mammals living in urban environments tend to be more of a nuisance to human inhabitants than birds, because they are often regarded as pests -- for example rats and bats -- and damage structures or goods -- as wild boars do. "It's important to gain more insight into how mammals live in urban environments, so we can eventually achieve a more peaceful coexistence," Santini says.

Traits that benefit urban mammals

Santini and colleagues collected studies from all over the world that recorded the number of mammal species in cities. "The large number of studies that have already been conducted show that birds in cities, for example crows, tend to be cleverer, meaning that they are better able to adapt to unexpected situations. However, mammals in cities are far less investigated, and only studies on a single mammal species, such as bats, have been carried out.

Mammals have way more diverse traits than birds, such as a higher diversity in body structure, size, life-history and ecology. Therefore, we were curious to know whether there are particular traits that are positively affecting the ability of mammal species to flourish in new ecosystems, such as urban environments."

Larger litters, brains and bodies

The finding that stands out most is that all groups of urban mammals seem to produce more young. Santini explains: "In general, animals that produce larger litters do so to compensate for a high mortality rate amongst their young. This suggests that a high mortality rate due to, for example, road traffic accidents, persecution by humans, and predation by domestic cats and dogs could be a major selective pressure for mammals in urban environments."

Differences in other traits were less explicit. "For example a larger brain mass appears to be mostly associated with carnivores and primates who only occasionally visit urban environments, such as jackals, wolves, bears and baboons, rather than with mammals who permanently live in cities, such as genet cats and mongooses among carnivores, or hedgehogs and shrews among insectivores. We also found that carnivores and primates that sporadically visit cities tend to be larger than average. This may be because they need to cover large distances in short times."

Different strategies for different species

Overall, the results indicate that different groups of mammals use different strategies to deal with the urban environment. "However, because the number of mammal species in an urban environments compared to the total number of mammal species is quite small -- 190 out of approximately 6,000 species -- this makes the statistics quite challenging, which makes it hard to make definite statements about specific groups of mammals and traits."

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Beyond the black hole singularity

Our first glimpses into the physics that exist near the center of a black hole are being made possible using "loop quantum gravity" -- a theory that uses quantum mechanics to extend gravitational physics beyond Einstein's theory of general relativity. Loop quantum gravity, originated at Penn State and subsequently developed by a large number of scientists worldwide, is opening up a new paradigm in modern physics. The theory has emerged as a leading candidate to analyze extreme cosmological and astrophysical phenomena in parts of the universe, like black holes, where the equations of general relativity cease to be useful.

Previous work in loop quantum gravity that was highly influential in the field analyzed the quantum nature of the Big Bang, and now two new papers by Abhay Ashtekar and Javier Olmedo at Penn State and Parampreet Singh at Louisiana State University extend those results to black hole interiors. The papers appear as "Editors' suggestions" in the journals Physical Review Letters and Physical Review on December 10, 2018 and were also highlighted in a Viewpoint article in the journal Physics.

"The best theory of gravity that we have today is general relativity, but it has limitations," said Ashtekar, Evan Pugh Professor of Physics, holder of the Eberly Family Chair in Physics, and director of the Penn State Institute for Gravitation and the Cosmos. "For example, general relativity predicts that there are places in the universe where gravity becomes infinite and space-time simply ends. We refer to these places as 'singularities.' But even Einstein agreed that this limitation of general relativity results from the fact that it ignores quantum mechanics."

At the center of a black hole the gravity is so strong that, according to general relativity, space-time becomes so extremely curved that ultimately the curvature becomes infinite. This results in space-time having a jagged edge, beyond which physics no longer exists -- the singularity. Another example of a singularity is the Big Bang. Asking what happened before the Big Bang is a meaningless question in general relativity, because space-time ends, and there is no before. But modifications to Einstein's equations that incorporated quantum mechanics through loop quantum gravity allowed researchers to extend physics beyond the Big Bang and make new predictions. The two recent papers have accomplished the same thing for the black hole singularity.

"The basis of loop quantum gravity is Einstein's discovery that the geometry of space-time is not just a stage on which cosmological events are acted out, but it is itself a physical entity that can be bent," said Ashtekar. "As a physical entity the geometry of space-time is made up of some fundamental units, just as matter is made up of atoms. These units of geometry -- called 'quantum excitations' -- are orders of magnitude smaller than we can detect with today's technology, but we have precise quantum equations that predict their behavior, and one of the best places to look for their effects is at the center of a black hole." According to general relativity, at the center of a black hole gravity becomes infinite so everything that goes in, including the information needed for physical calculations, is lost. This leads to the celebrated 'information paradox' that theoretical physicists have been grappling with for over 40 years. However, the quantum corrections of loop quantum gravity allow for a repulsive force that can overwhelm even the strongest pull of classical gravity and therefore physics can continue to exist. This opens an avenue to show in detail that there is no loss of information at the center of a blackhole, which the researchers are now pursuing.

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Newly discovered adolescent star seen undergoing 'growth spurt'

3-panel layout, showing the outbursting star.

Astronomers have discovered a young star undergoing a rare growth spurt -- giving a fascinating glimpse into the development of these distant stellar objects.

A team of international researchers, including experts from the University of Exeter's Physics and Astronomy department, have observed a rare stellar outburst on a newfound star, called Gaia 17bpi.

Gaia 17bpi belongs to a group of stars known as FU Ori's, named after the original member of the group, FU Orionis found in the Orion constellation.

Typically these FU Ori stars, which are less than a few million years old, are hidden behind thick clouds of dust and are therefore hard to observe.

However, the research team spotted the star undertaking a dramatic phase of evolution, whereby matter swirling around falls onto the star, and so bulking up its mass. The team was able to see this stellar outburst through both infrared and visible light.

Gaia 17bpi is only the 25th member of the FU Ori class found to date, and one of only about a dozen caught in the act of an outburst.

The research is published in The Astrophysical Journal.

Professor Tim Naylor, from Exeter's Astrophysics group and co-author of the study said: "It's taken a lot of patient waiting and careful sifting of data to uncover this star, but once we realised what was going it has exceeded expectations.

"It also gives us insight into events which may have happened as the planets in our own Solar System were beginning to form from a disc of material around the sun."

Gaia 17bpi was first spotted by the European Space Agency's Gaia satellite, which scans the sky continuously and makes precise measurements of stars in visible light. When Gaia spots a change in a star's brightness, an alert goes out to the astronomy community.

Exeter graduate student , and co-author of the study Sam Morrell was the first to notice that the star had brightened. Fellow members of the research team took the discovery forward, and discovered that the star's brightening had been independently captured in infrared light by NASA's asteroid-hunting NEOWISE satellite at the same time that Gaia saw it, as well as one-and-a-half-years earlier.

NASA's infrared-sensing Spitzer Space Telescope also happened to have witnessed the beginning of the star's brightening phase twice back in 2014, giving the researchers a bonanza of infrared data.

"These FU Ori events are extremely important in our current understanding of the process of star formation but have remained almost mythical because they have been so difficult to observe," says Lynne Hillenbrand, professor of astronomy at Caltech and lead author of a new report. "This is actually the first time we've ever seen one of these events as it happens in both optical and infrared light, and these data have let us map the movement of material through the disk and onto the star."

The new findings shine light on some of the longstanding mysteries surrounding the evolution of young stars, including how a star acquires all of its mass. Theorists believe that FU Ori events -- in which mass is dumped from the disk onto the star over a total period of about 100 years -- may help solve the riddle.

The new study shows, with the most detail yet, how material moves from the midrange of a disk, in a region located around one astronomical unit -- the distance between the Earth and the sun -- from the star, to the star itself.

NEOWISE and Spitzer were the first to pick up signs of the buildup of material in the middle of the disk. As the material started to accumulate in the disk, it warmed up, giving off infrared light. Then, as this material fell onto the star, it heated up even more, giving off visible light, which is what Gaia detected.

"While NEOWISE's primary mission is detecting nearby solar system objects, it also images all of the background stars and galaxies as it sweeps around the sky every six months," says co-author Roc Cutri, lead scientist for the NEOWISE Data Center at IPAC, an astronomy and data center at Caltech. "NEOWISE has been surveying in this way for five years now, so it is very effective for detecting changes in the brightness of objects."

Carlos Contreras, a Postdoctoral Research Fellow from the University of Exeter and co-author of the study added: "The FU Ori-type outbursts could also have an impact on the early formation and evolution of the planets that form in the discs around young stars.

The discovery of Gaia 17bpi was the by-product of an Exeter programme that has been monitoring a large sample of young stars using the data from the Gaia satellite, to measure the frequency of the FU Ori events during the planet forming stage."

Read more at Science Daily

A mountain of evidence on air pollution's harms to children

A new study led by researchers at the Columbia Center for Children's Environmental Health (CCCEH) organizes the available scientific evidence on the effects of air pollution on children's health. The paper in the journal Environmental Research is the first comprehensive review of the associations between various fossil fuel combustion pollutants and multiple health effects in children in the context of assessing the benefits of air pollution and climate change policies.

The researchers say their goal is to expand the kinds of health outcomes used in calculations of the health and economic benefits of implementing clean air and climate change policies which are largely limited to the effects of air pollution on premature deaths and other outcomes in adults. The new paper aggregates research on outcomes, including adverse birth outcomes, cognitive and behavioral problems, and asthma incidence.

"Policies to reduce fossil fuel emissions serve a dual purpose, both reducing air pollution and mitigating climate change, with sizable combined health and economic benefits," says first author Frederica Perera, PhD, director of CCCEH and professor of Environmental Health Sciences. "However, because only a few adverse outcomes in children have been considered, policymakers and the public have not yet seen the extent of the potential benefits of clean air and climate change policies, particularly for children."

The researchers reviewed 205 peer-reviewed studies published between January 1, 2000 and April 30, 2018 which provided information on the relationship between the concentration of exposures to air pollutants and health outcomes. The studies relate to fuel combustion by-products, including toxic air pollutants such as particulate matter (PM2.5), polycyclic aromatic hydrocarbons (PAH), and nitrogen dioxide (NO2). A table provides information on the risk of health outcomes for exposure by study, encompassing research on six continents.

"There is extensive evidence on the many harms of air pollution on children's health," says Perera. "Our paper presents these findings in a convenient fashion to support clean air and climate change policies that protect children's health."

The World Health Organization (WHO) has estimated that more than 40 percent of the burden of environmentally related disease and about 90 percent of the burden of climate change is borne by children under five, although that age group constitutes only 10 percent of the global population. The direct health impacts in children of air pollution from fossil fuel combustion include adverse birth outcomes, impairment of cognitive and behavioral development, respiratory illness, and potentially childhood cancer. As a major driver of climate change, combustion of fossil fuel is also directly and indirectly contributing to illness, injury, death, and impaired mental health in children through more frequent and severe heat events, coastal and inland flooding, drought, forest fires, intense storms, the spread of infectious disease vectors, increased food insecurity, and greater social and political instability. These impacts are expected to worsen in the future.

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Small changes in oxygen levels have big implications for ocean life

This is Lucicutia hulsemannae, a copepod that stays at the Lower Oxycline of the Oxygen Minimum Zone (OMZ). The organism is remarkably tolerant of extremely low oxygen levels, but very sensitive to small changes in those levels.

Oceanographers at the University of Rhode Island have found that even slight levels of ocean oxygen loss, or deoxygenation, have big consequences for tiny marine organisms called zooplankton.

Zooplankton are important components of the food web in the expanse of deep, open ocean called the midwater. Within this slice of ocean below the surface and above the seafloor are oxygen minimum zones (OMZs), large regions of very low oxygen. Unlike coastal "dead zones" where oxygen levels can suddenly plummet and kill marine life not acclimated to the conditions, zooplankton in OMZs are specially adapted to live where other organisms -- especially predators -- cannot. But OMZs are expanding due to climate change, and even slight changes to the low oxygen levels can push zooplankton beyond their extraordinary physiological limits.

"Although the animals in the ocean's oxygen minimum zone have adapted over millions of years to the very low oxygen of this extreme and widespread midwater habitat, they are living at the very limits of their physiological capability," said Karen Wishner, a professor of oceanography at URI's Graduate School of Oceanography and lead author of a new paper on deoxygenation and zooplankton in the Eastern Tropical North Pacific OMZ. "Our research shows that they are sensitive to very small changes in oxygen, and decrease in abundance when oxygen gets just a little bit lower."

The research team, which this week published their findings in Science Advances, found more natural variability in oxygen levels in the OMZ than previously known. This has a direct effect on the distribution of many types of zooplankton because, as the team discovered, the organisms respond to a less than 1 percent reduction in oxygen levels.

While zooplankton have had millions of years to adapt to conditions in the OMZ, these low oxygen zones may expand rapidly due to climate change, leading to major unanticipated changes to midwater ecosystems. For example, an expansion of the OMZ into shallower waters may make zooplankton more susceptible to predators like fish. If this leads to a zooplankton population crash, it will have impacts all the way up the food chain.

"Further loss of oxygen in ocean waters is predicted in the future as a result of global warming, and these animals may be unable to adapt and persist," Wishner said. "They are important components of the food web of oceanic ecosystems, and their loss could potentially impact top predators, including whales and commercially important fisheries."

From Science Daily

Himalayan marmot genome offers clues to life at extremely high altitudes

This image shows a pair of Himalayan marmots.

Himalayan marmots can survive at altitudes up to 5,000 meters in the Himalayan regions of India, Nepal, and Pakistan and on the Qinghai-Tibetan Plateau of China, where many of them face extreme cold, little oxygen, and few other resources. Now, researchers have sequenced the first complete Himalayan marmot genome, which may help them to better explain how the marmots live in such extremes.

The findings, which appear December 20 in the journal iScience, hint at the genetic mechanisms underlying high-altitude adaptation and hibernation, the researchers say. They also serve as a valuable resource for researchers studying marmot evolution, highland disease, and cold adaptation.

"As one of the highest-altitude-dwelling mammals, the Himalayan marmot is chronically exposed to cold temperature, hypoxia, and intense UV radiation," said Enqi Liu of Xi'an Jiaotong University Health Science Center in China. "They also hibernate for more than six months during the wintertime."

Those striking biological features led Liu and his team, including first author Liang Bai, to consider the Himalayan marmot as an ideal animal model for studying the molecular mechanisms of adaptation to extreme environments. To begin, they sequenced and assembled a complete draft genome of a male Himalayan marmot. They also re-sequenced 20 other Himalayan marmots, including individuals living at high and low altitudes, and four other marmot species. Additionally, RNA sequencing was done to compare gene-expression differences between marmots in a state of torpor and awake marmots.

The DNA data show that the Himalayan marmot diverged from the Mongolian marmot about 2 million years ago. The researchers identified two genes, Slc25a14 and ?Aamp (a processed pseudogene), that have been selected in different directions in marmots living at low versus high altitudes, suggesting they are related to survival in high-altitude populations under conditions of extremely low oxygen.

They further suggest that Slc25a14 may have an important neuroprotective role. The shift in ?Aamp affects the stability of RNA encoding the gene Aamp, which may be a protective strategy to prevent the excess growth of new blood vessels under extremely low-oxygen conditions.

The RNA sequencing data show that gene-expression changes occur in the liver and brain during hibernation. These include genes in the fatty acid metabolism pathway as well as blood clotting and stem cell differentiation.

Interestingly, a previous study suggested that because the hibernator's brain is exposed to near-freezing temperatures and has decreased blood flow, there is an increased risk of blood clots, the researchers note. Their brain stem cells may also be better prepared to repair injuries as an adaptation needed to survive extreme environmental stresses.

The researchers say they plan to continue improving the quality of the Himalayan marmot's genome. They note that the Himalayan marmot is also known for being highly susceptible to woodchuck hepatitis virus and is a natural host and transmitter of the plague to humans.

Read more at Science Daily

Mighty morphing materials take complex shapes

A face made of a unique polymer at Rice University takes shape when cooled and flattens when heated. The material may be useful in the creation of soft robots and for biomedical applications.

Rice University scientists have created a rubbery, shape-shifting material that morphs from one sophisticated form to another on demand.

The shapes programmed into a polymer by materials scientist Rafael Verduzco and graduate student Morgan Barnes appear in ambient conditions and melt away when heat is applied. The process also works in reverse.

The smooth operation belies a battle at the nanoscale, where liquid crystals and the elastomer in which they're embedded fight for control. When cool, the shape programmed into the liquid crystals dominates, but when heated, the crystals relax within the rubber band-like elastomer, like ice melting into water.

In most of the samples Barnes has made so far -- including a face, a Rice logo, a Lego block and a rose -- the material takes on its complex shape at room temperature, but when heated to a transition temperature of about 80 degrees Celsius (176 degrees Fahrenheit), it collapses into a flat sheet. When the heat is removed, the shapes pop back up within a couple of minutes.

As fanciful as this seems, the material shows promise for soft robots that mimic organisms and in biomedical applications that require materials that take pre-programmed shapes at body temperature.

The research is described in the Royal Society of Chemistry journal Soft Matter.

"These are made with two-step chemistry that has been done for a long time," said Verduzco, a professor of chemical and biomolecular engineering and of materials science and nanoengineering. "People have focused on patterning liquid crystals, but they hadn't thought about how these two networks interact with each other.

"We thought if we could optimize the balance between the networks -- make them not too stiff and not too soft -- we could get these sophisticated shape changes."

The liquid crystal state is easiest to program, he said. Once the material is given shape in a mold, five minutes of curing under ultraviolet light sets the crystalline order. Barnes also made samples that switch between two shapes.

"Instead of simple uniaxial shape changes, where you have something that lengthens and contracts, we're able to have something that goes from a 2D shape to a 3D shape, or from one 3D shape to another 3D shape," she said.

The lab's next target is to lower the transition temperature. "Activation at body temperature opens us up to a lot more applications," Barnes said. She said tactile smartphone buttons that appear when touched or reactive braille text for the visually impaired are within reach.

Read more at Science Daily

Faint starlight in Hubble images reveals distribution of dark matter

Abell S1063, a galaxy cluster, was observed by the NASA/ESA Hubble Space Telescope as part of the Frontier Fields program. The huge mass of the cluster -- containing both baryonic matter and dark matter -- acts as cosmic magnification glass and deforms objects behind it. In the past astronomers used this gravitational lensing effect to calculate the distribution of dark matter in galaxy clusters.

Astronomers using data from the NASA/ESA Hubble Space Telescope have employed a revolutionary method to detect dark matter in galaxy clusters. The method allows astronomers to "see" the distribution of dark matter more accurately than any other method used to date and it could possibly be used to explore the ultimate nature of dark matter. The results were published in the journal Monthly Notices of the Royal Astronomical Society.

In recent decades astronomers have tried to understand the true nature of the mysterious substance that makes up most of the matter in the Universe -- dark matter -- and to map its distribution in the Universe. Now two astronomers from Australia and Spain have used data from the Frontier Fields programme of the NASA/ESA Hubble Space Telescope to accurately study the distribution of dark matter.

"We have found a way to 'see' dark matter," explains Mireia Montes (University of New South Wales, Australia), lead author of the study. "We have found that very faint light in galaxy clusters, the intracluster light, maps how dark matter is distributed."

Intracluster light is a byproduct of interactions between galaxies. In the course of these interactions, individual stars are stripped from their galaxies and float freely within the cluster. Once free from their galaxies, they end up where the majority of the mass of the cluster, mostly dark matter, resides.

"These stars have an identical distribution to the dark matter, as far as our current technology allows us to study," explained Montes. Both the dark matter and these isolated stars -- which form the intracluster light -- act as collisionless components. These follow the gravitational potential of the cluster itself. The study showed that the intracluster light is aligned with the dark matter, tracing its distribution more accurately than any other method relying on luminous tracers used so far.

This method is also more efficient than the more complex method of using gravitational lensing. While the latter requires both accurate lensing reconstruction and time-consuming spectroscopic campaigns, the method presented by Montes utilises only deep imaging. This means more clusters can be studied with the new method in the same amount of observation time.

The results of the study introduce the possibility of exploring the ultimate nature of dark matter. "If dark matter is self-interacting we could detect this as tiny departures in the dark matter distribution compared to this very faint stellar glow," highlights Ignacio Trujillo (Instituto de Astrofísica de Canarias, Spain), co-author of the study. Currently, all that is known about dark matter is that it appears to interact with regular matter gravitationally, but not in any other way. To find that it self-interacts would place significant constraints on its identity.

For now, Montes and Trujillo plan to survey more of the original six clusters to see if their method remains accurate. Another important test of their method will be the observation and analysis of additional galaxy clusters by other research teams, to add to the data set and confirm their findings.

The team can also look forward to the application of the same techniques using future space-based telescopes like the NASA/ESA/CSA James Webb Space Telescope, which will have even more sensitive instruments able to resolve faint intracluster light in the distant Universe.

Read more at Science Daily

The oldest large-sized predatory dinosaur comes from the Italian Alps

At the Natural History Museum of Milan, paleontologist Cristiano Dal Sasso (left) and co-authors Simone Maganuco and Andrea Cau (center and right) examine the bones of Saltriovenator, deposited in the Museum collections.

Early Jurassic predatory dinosaurs are very rare, and mostly small in size. Saltriovenator zanellai, a new genus and species described in the peer-reviewed journal PeerJ -- the Journal of Life and Environmental Sciences by Italian paleontologists, is the oldest known ceratosaurian, and the world's largest (one ton) predatory dinosaur from the Lower Jurassic (Sinemurian, ~198 Mya).

This unique specimen, which also represents the first Jurassic dinosaur from Italy, was accidentally discovered in 1996 by a fossil amateur within a quarry near Saltrio, some 80 km N-E of Milan. Many bones of Saltriovenator bear feeding marks by marine invertebrates, which represent the first case on dinosaurian remains and indicate that the dinosaur carcass floated in a marine basin and then sunk, remaining on the sea bottom for quite a long time before burial.

Although fragmentary, "Saltriovenator shows a mosaic of ancestral and advanced anatomical features, respectively seen in the four-fingered dilophosaurids and ceratosaurians, and the three-fingered tetanuran theropods, such as allosaurids," says first author Cristiano Dal Sasso, of the Natural History Museum of Milan, who reassembled and studied the fossil for several years.

"Paleohistological analysis indicates that Saltriovenator was a still growing subadult individual, therefore its estimated size is all the more remarkable, in the context of the Early Jurassic period," says co-author Simone Maganuco.

"The evolutionary 'arms race' between stockier predatory and giant herbivorous dinosaurs, involving progressively larger species, had already begun 200 million of years ago."

The evolution of the hand of birds from their dinosaurian ancestors is still hotly debated. "The grasping hand of Saltriovenator fills a key gap in the theropod evolutionary tree: predatory dinosaurs progressively lost the pinky and ring fingers, and acquired the three-fingered hand which is the precursor of the avian wing," remarks co-author Andrea Cau.

From Science Daily

Huge armored dinosaurs battled overheating with nasal air-conditioning

Heat exchange through the highly convoluted nasal passages of the Cretaceous ankylosaurian dinosaur Euoplocephalus not only efficiently warmed and humidified the inspired air on its way to the lungs but also cooled the blood running through the nasal veins, much of which was destined for the brain. In this way, the brain was protected from the high temperatures of the hot arterial blood coming from the body core.

Being a gigantic dinosaur presented some challenges, such as overheating in the Cretaceous sun and frying your brain. Researchers from Ohio University and NYITCOM at Arkansas State show in a new article in PLOS ONE that the heavily armored, club-tailed ankylosaurs had a built-in air conditioner in their snouts.

"The huge bodies that we see in most dinosaurs must have gotten really hot in warm Mesozoic climates," said Jason Bourke, Assistant Professor at the New York Institute of Technology College of Osteopathic Medicine at Arkansas State and lead author of the study. "Brains don't like that, so we wanted to see if there were ways to protect the brain from cooking. It turns out the nose may be the key."

Bourke and the team used CT scanning and a powerful engineering approach called computational fluid dynamics to simulate how air moved through the nasal passages of two different ankylosaur species, the hippo-sized Panoplosaurus and larger rhino-sized Euoplocephalus, to test how well ankylosaur noses transferred heat from the body to the inhaled air.

"A decade ago, my colleague Ryan Ridgely and I published the discovery that ankylosaurs had insanely long nasal passages coiled up in their snouts," said study co-author Lawrence Witmer, professor at the Ohio University Heritage College of Osteopathic Medicine. "These convoluted airways looked like a kid's 'crazy-straw!' It was completely unexpected and cried out for explanation. I was thrilled when Jason took up the problem as part of his doctoral research in our lab."

"This project is an excellent example of how advances in CT scanning, 3-D reconstruction, imaging, and computational fluid dynamics modeling can be used in biological research to test long-standing hypotheses," said Kathy Dickson, a program officer at the National Science Foundation that funded the research. "From these new images and models, fossils can provide further insight into extinct organisms like the ankylosaur -- in this case, offering an explanation of how unusual features actually function physiologically."

Smell may be a primary function of the nose, but noses are also heat exchangers, making sure that air is warmed and humidified before it reaches our delicate lungs. To accomplish this effective air conditioning, birds and mammals, including humans, rely on thin curls of bone and cartilage within their nasal cavities called turbinates, which increase the surface area, allowing for air to come into contact with more of the nasal walls. "Ankylosaurs didn't have turbinates, but instead made their noses very long and twisty," said Bourke.

When the researchers compared their findings to data from living animals, they discovered that the dinosaurs' noses were just as efficient at warming and cooling respired air. "This was a case of nature finding a different solution to the same problem," said Bourke.

Just how long were these nasal passages? In Panoplosaurus, they were a bit longer than the skull itself and in Euoplocephalus they were almost twice as long as the skull, which is why they're coiled up in the snout. To see if nasal passage length was the reason for this efficiency, Bourke ran alternative models with shorter, simpler nasal passages that ran directly from the nostril to the throat, as in most other animals. The results clearly showed that nose length was indeed the key to their air-conditioning ability. "When we stuck a short, simple nose in their snouts, heat-transfer rates dropped over 50 percent in both dinosaurs. They were less efficient and didn't work very well," said Bourke.

Another line of evidence that these noses were air conditioners that helped cool the brain came from analyses of blood flow.

"When we reconstructed the blood vessels, based on bony grooves and canals, we found a rich blood supply running right next to these convoluted nasal passages," said Ruger Porter, lecturer at the Ohio University Heritage College of Osteopathic Medicine and one of the study's co-authors. "Hot blood from the body core would travel through these blood vessels and transfer their heat to the incoming air. Simultaneously, evaporation of moisture in the long nasal passages cooled the venous blood destined for the brain."

So why the need for such effective heat exchangers? The large bodies of Panoplosaurus and Euoplocephalus were really good at retaining heat, which is good for staying warm, but bad when the animals need to cool off. This heat-shedding problem would have put them at risk of overheating even on cloudy days. In the absence of some protective mechanism, the delicate neural tissue of the brain could be damaged by the hot blood from the body core.

"Sure, their brains were almost comically small," Bourke said. "But they're still their brains and needed protection."

The complicated nasal airways of these dinosaurs were acting as radiators to cool down the brain with a constant flow of cooled venous blood, allowing them to keep a cool head at all times. This natural engineering feat also may have allowed the evolution of the great sizes of so many dinosaurs.

"When we look at the nasal cavity and airway in dinosaurs, we find that the most elaborate noses are found in the large dinosaur species, which suggests that the physiological stresses of large body size may have spurred some of these anatomical novelties to help regulate brain temperatures," Witmer said.

The next step for the researchers is to examine other dinosaurs to determine when this nasal enlargement happened.

"We know that large dinosaurs had these crazy airways, but at exactly what size did this happen?" Bourke said. "Was this elaboration gradual as body size increased, or is there a threshold size where a run-of-the-mill nose can no longer do the job? We just don't know yet."

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Some prehistoric horses were homebodies

UC researchers found that prehistoric horses in Florida were sedentary, much like wild horses today in Assateague Island National Seashore.

Unlike today's zebras, prehistoric horses in parts of North America did not make epic migrations to find food or fresh water, according to a new study by the University of Cincinnati.

The findings suggest Florida was something of a horse paradise 5 million years ago, providing everything the animals could want in a relatively small area.

The study was published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology.

Plains zebras and Mongolian wild horses take on epic migrations each year to find water or green grass.

The Mongolian wild horse, also known as a Przewalski's horse, travels as much as 13 miles per day. And Burchell's zebras in southern Africa are known for their seasonal migrations that take them as far as 300 miles and back as they follow the rains to green grass.

But geologists in UC's McMicken College of Arts and Sciences found that prehistoric horses in coastal Florida lived and died within a comparatively small area.

"It seems that these horses in Florida were relatively sedentary. They didn't travel far distances," said Jenelle Wallace, a UC graduate and lead author of the study.

The study was the basis of Wallace's master's thesis. Today, she works as an engineering geologist for the New York State Department of Environmental Conservation.

"My third spoken word after mom and dad was horse," Wallace said. "I've loved them ever since I was little."

The world's first horses originated in North America. They lived there for 55 million years before spreading to Asia and Africa while going extinct on their home continent about 12,000 years ago.

The small three-toed animals lived like antelope, browsing leaves in deep forests. But during the Miocene Period between 23 million and 8 million years ago, horse evolution exploded into 15 different families. Horses developed bigger bodies, longer legs and hard hooves in place of toes to help them cover more ground.

Their teeth also changed, becoming bigger and longer for cropping coarse grass covered in abrasive silica dust instead of plucking soft leaves. It's these teeth that helped UC researchers study how extinct horses lived.

UC's geologists compared strontium isotopes found in fossilized horse teeth to the strontium in bedrock in different parts of the American Southeast to track the horses' wanderings. Plants such as grass absorb strontium from the earth and the horses, in turn, absorb that strontium while grazing. In this way, strontium serves as a geographic marker.

?UC geology professors and study co-authors Brooke Crowley and Joshua Miller have used this technique to track the movements of other animals, both living and prehistoric. Crowley used bones collected from the nests of secretive goshawks to map the birds' travels in Madagascar. She and Miller also are studying the movement of Ice Age mastodons in North America.

"There is a lot of opportunity for expanding the use of strontium to look at a variety of animal groups, time periods and locations," Crowley said.

The study examined seven species of horse along with two known leaf-eaters: a prehistoric tapir and a distant relative of elephants called a gomphothere.

The results were surprising, researchers said.

Of all the animals studied, the tapir seemed to have the widest geographic range based on the high variability of strontium found in its teeth. But given that modern tapirs have relatively modest home ranges, researchers said it's more likely that prehistoric tapirs consumed river plants that absorbed nutrients carried far downstream.

Among the horses, the researchers found little variation in the size of their ranges. But the strontium showed a connection between horses and the sea. Like modern horses today in places such as Assateague Island National Seashore, prehistoric horses might have fed along the coast. Researchers suggested the vegetation horses consumed was influenced by marine-derived strontium from seaspray, precipitation or saltwater intrusion into groundwater.

The study was funded by grants from the UC Geology Department, Sigma Xi, the Geological Society of America and the American Society of Mammalogists along with the Association for Women Geoscientists Winifred Goldring Award.

"The study suggests we're not the only couch potatoes. If animals don't have to move, they won't," Miller said.

Migrating is dangerous business, Miller said. Animals face injury, illness and starvation when they travel great distances. And in the Miocene Period, horses had to outwit plenty of big predators such as saber-toothed cats.

"The energetic costs of moving are high," Miller said.

Crowley, who also teaches in UC's Department of Anthropology, said studies like this shed light on the habitat needs of animals long before they were influenced by human activities.

"Having a deep perspective is really important for understanding a species' needs in conservation and management," Crowley said. "If we just look at a narrow window of time -- like 50 or 100 years -- we don't get a good picture of a species when it's not in crisis."

Using the geologic record, researchers can piece together how animals interacted, what allowed them to thrive and what ultimately caused them to perish, she said.

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Groups of pilot whales have their own dialects

The groups of pilot whales all use the same habitat, but have different vocal repertoires. This means that they're purposely not associating with each other, says WHOI researcher Amy Van Cise.

In humans, different social groups, cities, or regions often have distinct accents and dialects. Those vocal traits are not unique to us, however. A new study from the Woods Hole Oceanographic Institution (WHOI) has found that short-finned pilot whales living off the coast of Hawai'i have their own sorts of vocal dialects, a discovery that may help researchers understand the whales' complex social structure. The study was published on Dec. 14, 2018, in the journal Behavioral Ecology and Sociobiology.

"These groups of pilot whales all use the same habitat. The fact that they have different vocal repertoires means that they're purposely not associating with each other," says Amy Van Cise, a Postdoctoral Scholar at WHOI and lead author on the study. "It's sort of like if you've got hipsters and prep kids in the same high school -- each group has different slang. They identify themselves with certain speech to maintain that separation."

This finding could be especially important for understanding the species, since relatively little is currently known about their social behavior.

"On a broad-scale they are understudied, mainly because of where they spend their time," says biologist Robin Baird of the Cascadia Research Consortium, a co-author on the paper. "Hawai'i is one of the only locations in the U.S. where you can fairly quickly and easily get to areas where you can find pilot whales, while staying in good working conditions."

In a previous 15-year study of the Hawai'ian whales, Baird and colleagues were able to photograph, identify, and categorize groups of whales, creating a database of associations. The researchers also took tiny biopsies of skin from the back of each whale they approached to gather genetic information.

Based on that data, Van Cise found that the lowest and smallest level of organization, called a "unit," of pilot whales, appears to be made up of a handful of directly-related individuals. Those units combine to form "clusters" -- essentially extended family -- and multiple families together make up a "community" of the whales.

This study builds on Van Cise's prior work. Over several years, she and Baird's team took a small boat off the coast of Hawai'i and Kaua'i Islands in search of pilot whales, identified individual whales, and recorded their calls with a specialized underwater microphone. She also continued taking genetic samples from the animals. Once finished, Van Cise and a team of volunteers painstakingly categorized individual types of whale calls on the recordings, sorting them into distinct groups.

"That let us effectively make a map of vocal repertoire that we could superimpose onto a map of the whales' social structure," she says. "If two social groups sound similar to each other acoustically, that likely means that that're that they're communicating with each other regularly, using similar habitats or hunting grounds and foraging habits. This gives us a better sense of the social ties between whale groups. In the long term, that could help us understand both their genetic diversity and their evolution."

That last part is especially important, Van Cise notes. In each family of whales, the genetic diversity between individuals isn't large -- children by necessity share many of their genes with their parents. Across the entire whale population, however, it's a different story. For that reason, she says, it'll be essential to conserve pilot whales at family level, rather than focusing on individuals.

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Why is sea level rising faster in some places along the US East Coast than others?

Beach on the east coast of the U.S.

Sea levels are rising globally from ocean warming and melting of land ice, but the seas aren't rising at the same rate everywhere. Sea levels have risen significantly faster in some U.S. East Coast regions compared to others. A new study led by the Woods Hole Oceanographic Institution (WHOI) reveals why.

Over the 20th century, sea level has risen about a foot and a half in coastal communities near Cape Hatteras in North Carolina and along the Chesapeake Bay in Virginia. In contrast, New York City and Miami have experienced about a 1-foot rise over the same period, while sea levels farther north in Portland, Maine, rose only about half a foot.

The reason is a phenomenon called "post-glacial rebound," explains Chris Piecuch, lead author of a study published on Dec. 20, 2018, in the journal Nature. Essentially, land areas in the Northern Hemisphere that once were covered by mammoth ice sheets during the last Ice Age -- such as Canada and parts of the Northeast U.S. -- were weighed down like a trampoline with a boulder on it. At the same time, land around the periphery of the ice sheets -- along the U.S. mid-Atlantic coast, for example -- rose up. As the ice sheets melted from their peak at the Last Glacial Maximum 26,500 years ago, the weighed-down areas gradually rebounded, while the peripheral lands started sinking, creating sort of a see-saw effect. Even though the ice sheets had disappeared by 7,000 years ago, the see-sawing of post-glacial rebound continues to this day.

To explore why sea levels rose faster during the last century in areas such as Norfolk Naval Station in Virginia and the Outer Banks in North Carolina, Piecuch and colleagues gathered tidal gauge measurements of sea levels, GPS satellite data that show how much the land has moved up and down over time, and fossils in sediment from salt marshes, which record past coastal sea levels. They combined all of this observational data with complex geophysical models -- something that has not been done before -- to give a more complete view of sea level changes since 1900.

The research team found that post-glacial rebound accounted for most of the variation in sea level rise along the East Coast. But, importantly, when that factor was stripped away, the researchers found that "sea level trends increased steadily from Maine all the way down to Florida," Piecuch said.

"The cause for that could involve more recent melting of glaciers and ice sheets, groundwater extraction and damming over the last century," Piecuch says. "Those effects move ice and water mass around at Earth's surface, and can impact the planet's crust, gravity field and sea level."

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Getting a glimpse inside the moon

The moon.

New research from University of Alberta physicists provides the first-ever model of our Moon's rotational dynamics, taking into consideration its solid inner core. Their model helps to explain why, as seen from Earth, the Moon appears to wobble on its axis.

The answer, said physicist Mathieu Dumberry, lies in the complex geometry of the Moon's orbit, locked in what is known as a Cassini state.

"The Moon goes around the Earth, but its orbit is inclined by about five degrees with respect to the normal to the ecliptic plane, the plane about which Earth rotates around the Sun. But just like the Earth's rotation axis is inclined by 23.5 degrees in space, the Moon's rotation axis is also inclined, by about 1.5 degrees," explained Dumberry, associate professor in the Department of Physics. "Over one orbit, it points at the same direction in space -- which is in the same plane as the normal to the orbit of the moon. This defines a Cassini state."

This type of lunar orbit was first observed by Giovanni Cassini more than four centuries ago. Since that time, the complex mathematical and physical elements of the Cassini state have been examined by scientists around the world. But what makes this model unique is accounting for a solid inner core at the centre of the Moon.

The heart of the matter

"Essentially, we took all forces into account and tried to predict the angle of the inner core of the Moon," explained Dumberry. "The tilt angle can be predicted, but we need to know accurately the deep interior structure on the Moon. However we know it is not aligned with the mantle or the fluid core. We determined that the inner core is tilted as much as 17 degrees away from the mantle in one direction or 33 degrees away in the other."

And, if scientists can identify the angle of the inner core, they will be able to develop a more accurate picture of the interior of the Moon.

"This is the first model of the rotational dynamics of the Moon that fully takes into account the presence of a solid inner core," said Christopher Stys, graduate student who conducted this research under the supervision of Dumberry. "Understanding the composition of the Moon's interior may provide insight to the events leading up to the formation of the Moon and the early history of the Earth."

From Science Daily

Sapphires and rubies in the sky

Illustration of one of the exotic super-Earth candidates, 55 Cnc e, which are rich in sapphires and rubies and might shimmer in blue and red colors.

Researchers   have discovered a new, exotic class of planets outside our solar system. These so-called super-Earths were formed at high temperatures close to their host star and contain high quantities of calcium, aluminium and their oxides -- including sapphire and ruby.

21 light years away from us in the constellation Cassiopeia, a planet orbits its star with a year that is just three days long. Its name is HD219134 b. With a mass almost five times that of Earth it is a so-called "super-Earth." Unlike the Earth however, it most likely does not have a massive core of iron, but is rich in calcium and aluminium. "Perhaps it shimmers red to blue like rubies and sapphires, because these gemstones are aluminium oxides which are common on the exoplanet," says Caroline Dorn, astrophysicist at the Institute for Computational Science of the University of Zurich. HD219134 b is one of three candidates likely to belong to a new, exotic class of exoplanets, as Caroline Dorn and her colleagues at the Universities of Zurich and Cambridge now report in the British journal MNRAS.

The researchers study the formation of planets using theoretical models and compare their results with data from observations. It is known that during their formation, stars such as the Sun were surrounded by a disc of gas and dust in which planets were born. Rocky planets like the Earth were formed out of the solid bodies leftover when the proto-planetary gas disc dispersed. These building blocks condensed out of the nebula gas as the disc cooled. "Normally, these building blocks are formed in regions where rock-forming elements such as iron, magnesium and silicon have condensed," explains Dorn who is associated to the NCCR PlanetS. The resulting planets have an Earth-like composition with an iron core. Most of the super-Earths known so far have been formed in such regions.

The composition of super-Earths is more diverse than expected

But there are also regions close to the star where it is much hotter. "There, many elements are still in the gas phase and the planetary building blocks have a completely different com-position," says the astrophysicist. With their models, the research team calculated what a planet being formed in such a hot region should look like. Their result: calcium and aluminium are the main constituents alongside magnesium and silicon, and there is hardly any iron. "This is why such planets cannot, for example, have a magnetic field like the Earth," says Dorn. And because the inner structure is so different, their cooling behavior and atmospheres will also differ from those of normal super-Earths. The team therefore speak of a new, exotic class of super-Earths formed from high-temperature condensates.

"What is exciting is that these objects are completely different from the majority of Earth-like planets," says Dorn -- "if they actually exist." The probability is high, as the astrophysicists explain in their paper. "In our calculations we found that these planets have 10 to 20 percent lower densities than the Earth," explains the first author. Other exoplanets with similarly low-densities were also analyzed by the team. "We looked at different scenarios to explain the observed densities," says Dorn. For example, a thick atmosphere could lead to a lower overall density. But two of the exoplanets studied, 55 Cancri e and WASP-47 e, orbit their star so closely that their surface temperature is almost 3000 degrees and they would have lost this gas envelope long ago. "On HD219134 b it's less hot and the situation is more complicated," explains Dorn. At first glance, the lower density could also be explained by deep oceans. But a second planet orbiting the star a little further out makes this scenario unlikely. A comparison of the two objects showed that the inner planet cannot contain more water or gas than the outer one. It is still unclear whether magma oceans can contribute to the lower density.

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Explaining differences in rates of evolution

Starting with a single species, new species may emerge in any of the three ways. In their study, ETH researchers examined whether certain species gave rise to new ones in one predominant way.

The rate at which evolution produces new species of plants and animals, or at which existing species die out, is a subject of much interest -- and not only to scientists. That's because the rates of speciation and extinction can tell us much about the history of our planet. If lots of new species emerge during an interval, this would indicate favourable conditions for life on earth. In contrast, extraordinary events can trigger mass extinctions, the most famous example of which was the event that wiped out the dinosaurs 66 million years ago, probably caused by a meteorite impact.

Mysterious discrepancy

It is difficult to determine the frequency with which species in the past emerged and then went extinct again. "There was no one there to witness these processes as they occurred," says Rachel Warnock, a postdoc in the Computational Evolution research group at ETH Zurich. This is why scientists attempt to deduce the rates of speciation and extinction through indirect methods. Some information comes from fossils dated to different geological eras.

Another source of information comes from species that exist today. In particular, from what are known as phylogenetic (or evolutionary) trees of living species, which are based on DNA analysis. By applying statistical methods to these trees, scientists can determine how often new species emerged and old ones died off in the past.

However, these two approaches are problematic in that they often produce conflicting results: the speciation and extinction rates derived from the fossil record are often much higher than those calculated through phylogenetic methods. To date, it has been unclear what was responsible for this discrepancy.

Combining different approaches

But now, in collaboration with other scientists, Rachel Warnock and head of the Computational Evolution research group Tanja Stadler have found an explanation. "The two methods are based on different assumptions about how new species are formed," Warnock says. This is why they arrive at different conclusions. But if they account for these different assumptions, then it is possible to harmonise the results.

The researchers were able to demonstrate this by looking at various groups of animals, such as whales, canines and bovines. Their success was due in part to a computer model they developed themselves: "Now we're able to unify both perspectives," says Warnock. The results of their work were published in the journal Nature Communications.

Insights into speciation

Current thinking maintains that there is not one, but rather multiple mechanisms by which new species emerge (see box). Each mechanism leads to different results; the process may produce one or two new species, while the original species either continues to exist or dies out. "When using the statistical methods to analyse phylogenies and fossils, scientists have thus far not taken these different possibilities explicitly into account," Warnock says.

The new model now incorporates them, thus ensuring that fossil-based and phylogenetic information produce compatible speciation and extinction rates.

It also provides indications as to which speciation mechanism predominated in a particular animal or plant group. For example, the evolutionary tree and the fossil record of whales reveals that the most frequent mode may be anagenesis; that is, original species are gradually transformed into new ones (mode 3; see box). In consequence, the model could be used in future studies to gain new insights into the evolution of organisms. It also helps to harmonise the results of fossil based and phylogenetic analysis better than before.

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Peering into Little Foot's 3.67-million-year-old brain

Virtual rendering of the brain endocast of "Little Foot". Photo of the original skull by M. Lotter and R.J. Clarke.

First ever endocast reconstruction of the nearly complete brain of the hominin known as Little Foot reveals a small brain combining ape-like and human-like features.

MicroCT scans of the Australopithecus fossil known as Little Foot shows that the brain of this ancient human relative was small and shows features that are similar to our own brain and others that are closer to our ancestor shared with living chimpanzees.

While the brain features structures similar to modern humans -- such as an asymmetrical structure and pattern of middle meningeal vessels -- some of its critical areas such as an expanded visual cortex and reduced parietal association cortex points to a condition that is distinct from us.

The Australopithecus fossil named Little Foot, an ancient human relative, was excavated over 14 years from the Sterkfontein Caves in South Africa, by Professor Ronald Clarke, from the University of the Witwatersrand (Wits). Its brain endocast was virtually extracted, described and analysed by Wits researcher, Dr Amélie Beaudet, and the Sterkfontein team by using MicroCT scans of the fossil.

The scans reveal impressions left on the skull by the brain and the vessels that feed it, along with the shape of the brain. Beaudet's research was released as the first in a series of papers planned for a special issue of this journal on the near-complete "Little Foot" skeleton in the Journal of Human Evolution.

"Our ability to reconstruct features of early hominin brains has been limited by the very fragmentary nature of the fossil record. The Little Foot endocast is exceptionally well preserved and relatively complete, allowing us to explore our own origins better than ever before," says Beaudet.

The endocast showed that Little Foot's brain was asymmetrical, with a distinct left occipital petalia. Brain asymmetry is essential for lateralisation of brain function. Asymmetry occurs in humans and living apes, as well as in other younger hominin endocasts. Little Foot now shows us that this brain asymmetry was present at a very early date (from 3.67 million years ago), and supports suggestions that it was probably present in the last common ancestor of hominins and other great apes.

Other brain structures, such as an expanded visual cortex, suggests that the brain of Little Foot probably had some features that are closer to the ancestor we share with living chimpanzees.

"In human evolution, when know that a reduced visual cortex, as we can see in our own brain, is related to a more expanded parietal cortex -- which is a critical cerebral area responsible for several aspects of sensory processing and sensorimotor integration," says Beaudet. "On the contrary, Little Foot has a large visual cortex, which is more similar to chimpanzees than to humans."

Beaudet and her colleagues compared the Little Foot endocast with endocasts of 10 other South African hominins dating between three and 1.5 million years ago. Their preliminary calculation of Little Foot's endocranial volume was found to be at the low end of the range for Australopithecus, which is in keeping with its great age and its place among other very early fossils of Australopithecus from East Africa.

The study also has shown that the vascular system in Australopithecus was more complex than previously thought, which raises new questions on the metabolism of the brain at this time. This might be consistent with a previous hypothesis suggesting that the endocranial vascular system in Australopithecus was closer to modern humans than it was in the geologically younger Paranthropus genus.

"This would mean that even if Little Foot's brain was different from us, the vascular system that allows for blood flow (which brings oxygen) and may control temperature in the brain -- both essential aspects for evolving a large and complex brain -- were possibly already present at that time," says Beaudet.

Given its geological age of over 3 million years, Little Foot's brain suggests that younger hominins evolved greater complexity in certain brain structures over time, perhaps in response to increasing environmental pressures experienced after 2.6 million years ago with continuing reduction in closed habitats.

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Space telescope detects water in a number of asteroids

By using a space-borne telescope, the team was able to successfully detect the presence of water in many asteroids.

Using the infrared satellite AKARI, a Japanese research team has detected the existence of water in the form of hydrated minerals in a number of asteroids for the first time. This discovery will contribute to our understanding of the distribution of water in our solar system, the evolution of asteroids, and the origin of water on Earth.

The findings were made by the team led by the Project Assistant Professor Fumihiko Usui (Graduate School of Science, Kobe University), the Associate Senior Researcher Sunao Hasegawa, the Aerospace Project Research Associate Takafumi Ootsubo (Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency), and Professor Emeritus Takashi Onaka (Graduate School of Science, University of Tokyo). The results were published on December 17 in the online Advanced Access edition of Publications of the Astronomical Society of Japan.

Our Earth is an aqua-planet, and is the only planet in our solar system where the presence of water on the planet surface has been confirmed. We are, however, not yet sure how our Earth acquired water. Recent studies have shown that other celestial bodies in our solar system have, or used to have, water in some form. Asteroids are considered to be one of the candidates that brought water to Earth. Note that the liquid water is not flowing on the surface of asteroids, but water is retained in asteroids as hydrated minerals, which were produced by chemical reactions of water and anhydrous rocks that occurred inside the asteroids, that is, aqueous alteration. Hydrated minerals are stable even above the sublimation temperature of water ice. Thus, by looking for hydrated minerals, we can investigate whether asteroids have water.

Infrared wavelengths contain characteristic spectral features of various substances, such as molecules, ice, and minerals, which cannot be observed at visible wavelengths. Therefore, it is indispensable to observe at infrared wavelengths for the study of solar system objects. Hydrated minerals exhibit diagnostic absorption features at around 2.7 micrometers. The absorption of water vapor and carbon dioxide in the terrestrial atmosphere prevents us from observing this wavelength with ground-based telescopes. It is absolutely necessary to make observations from outside of the atmosphere, that is, in space. However, observations with space-borne telescopes have been scarce; the Infrared Space Observatory (ISO), launched in 1995, did not have a sufficient sensitivity to make spectroscopy of faint asteroids and the Spitzer Space Telescope, launched in 2003, did not have a coverage of this wavelength range. For this reason, it has not fully been understood how much water is contained in asteroids.

The Japanese infrared satellite AKARI, launched in February 2006, was equipped with the Infrared Camera (IRC) that allowed us to obtain spectra at near-infrared wavelengths from 2 to 5 micrometers. Using this unique function, the spectroscopic observations of 66 asteroids  were carried out and their near-infrared spectra were obtained. This provides the first opportunity to study the features of hydrated minerals in asteroids at around the wavelength of 2.7 micrometers.

The observations detected absorption, which were attributed to hydrated minerals for 17 C-type asteroids. C-type asteroids, which appear dark at visible wavelengths, were believed to be rich in water and organic material, but the present observations with AKARI are the first to directly confirm the presence of hydrated minerals in these asteroids. The absorption strength detected at around 2.7 micrometers varies for each asteroid, and some show absorption features of other substances, such as water ice and ammonia-rich material at around 3.1 micrometers.

When examining C-type asteroids in more detail, the research team discovered a clear relationship between the wavelength of the deepest absorption and the depth of the absorption for the 2.7 micrometers feature. This shows a trend seen in the process where hydrated minerals are being heated up and gradually losing water. The heating energy could be supplied by the solar wind plasma, micrometeorite impacts, or the decay heat from radioactive isotopes in the rocks. This trend had been predicted by meteorite measurements, but this is the first time that it has been confirmed in asteroids. Many C-type asteroids display this trend, suggesting that C-type asteroids were formed by the agglomeration of rocks and water ice, then aqueous alteration occurred in the interior of asteroids to form hydrated minerals, and finally C-type asteroids were heated and dehydrated.

On the other hand, rocky S-type asteroids were considered to not contain water, unlike C-type asteroids. In the present study, hydrated minerals were not detected in most S-types, but it was newly discovered that there are exceptional cases of a few asteroids that show slight signs of hydrated minerals. The signs of water found in such S-type asteroids were probably not generated by aqueous alteration as in C-types, but were produced by collisions of other hydrated asteroids, that is, it is the exogenous origin that brought about the hydrated minerals. Asteroid collisions with each other occasionally occur. At the early stage of the solar system formation, a number of small bodies including asteroids were larger than the present, and collisional events must have been more frequent. From the fact that Earth would have experienced collisions with many asteroids, it is imagined that at least some amount of water on Earth was brought from asteroids by such collisions.

This study has confirmed the presence of water in asteroids. Spectra of the observed asteroids show common patterns. The size and the distance from the sun of the asteroid can be considered as important factors making differences of the spectra. To fully understand the observed patterns, it is necessary to accumulate observations of more asteroids as well as to compare with the measurement of meteorites collected on Earth. Dr. Usui comments: "By solving this puzzle, we can make a significant step towards identifying the source of Earth's water and unveiling the secret of how life began on Earth."

AKARI completed its operation in November 2011. For the next opportunity to perform spectroscopy in 2.7 micrometer wavelength with space-borne telescope, we will have to wait until the launch of the James Webb Space Telescope by NASA, scheduled in 2021.

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Fossils suggest flowers originated 50 million years earlier than thought

This is a Nanjinganthus fossil, showing its ovary (bottom centre), sepals and petals (on the sides) and a tree-shaped top.

Scientists have described a fossil plant species that suggests flowers bloomed in the Early Jurassic, more than 174 million years ago, according to new research in the open-access journal eLife.

Before now, angiosperms (flowering plants) were thought to have a history of no more than 130 million years. The discovery of the novel flower species, which the study authors named Nanjinganthus dendrostyla, throws widely accepted theories of plant evolution into question, by suggesting that they existed around 50 million years earlier. Nanjinganthus also has a variety of 'unexpected' characteristics according to almost all of these theories.

Angiosperms are an important member of the plant kingdom, and their origin has been the topic of long-standing debate among evolutionary biologists. Many previously thought angiosperms could be no more than 130 million years old. However, molecular clocks have indicated that they must be older than this. Until now, there has been no convincing fossil-based evidence to prove that they existed further back in time.

"Researchers were not certain where and how flowers came into existence because it seems that many flowers just popped up in the Cretaceous from nowhere," explains lead author Qiang Fu, Associate Research Professor at the Nanjing Institute of Geology and Paleontology, China. "Studying fossil flowers, especially those from earlier geologic periods, is the only reliable way to get an answer to these questions."

The team studied 264 specimens of 198 individual flowers preserved on 34 rock slabs from the South Xiangshan Formation -- an outcrop of rocks in the Nanjing region of China renowned for bearing fossils from the Early Jurassic epoch. The abundance of fossil samples used in the study allowed the researchers to dissect some of them and study them with sophisticated microscopy, providing high-resolution pictures of the flowers from different angles and magnifications. They then used this detailed information about the shape and structure of the different fossil flowers to reconstruct the features of Nanjinganthus dendrostyla.

The key feature of an angiosperm is 'angio-ovuly' -- the presence of fully enclosed ovules, which are precursors of seeds before pollination. In the current study, the reconstructed flower was found to have a cup-form receptacle and ovarian roof that together enclose the ovules/seeds. This was a crucial discovery, because the presence of this feature confirmed the flower's status as an angiosperm. Although there have been reports of angiosperms from the Middle-Late Jurassic epochs in northeastern China, there are structural features of Nanjinganthus that distinguish it from these other specimens and suggest that it is a new genus of angiosperms.

Having made this discovery, the team now wants to understand whether angiosperms are either monophyletic -- which would mean Nanjinganthus represents a stem group giving rise to all later species -- or polyphyletic, whereby Nanjinganthus represents an evolutionary dead end and has little to do with many later species.

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Fossil from the Big Bang discovered with W. M. Keck Observatory

Within the gas in the (blue) filaments connecting the (orange) galaxies lurk rare pockets of pristine gas -- vestiges of the Big Bang that have somehow been orphaned from the explosive, polluting deaths of stars, seen here as circular shock waves around some orange points.

A relic cloud of gas, orphaned after the Big Bang, has been discovered in the distant universe by astronomers using the world's most powerful optical telescope, the W. M. Keck Observatory on Maunakea, Hawaii.

The discovery of such a rare fossil, led by PhD student Fred Robert and Professor Michael Murphy at Swinburne University of Technology, offers new information about how the first galaxies in the universe formed.

"Everywhere we look, the gas in the universe is polluted by waste heavy elements from exploding stars," says Robert. "But this particular cloud seems pristine, unpolluted by stars even 1.5 billion years after the Big Bang."

"If it has any heavy elements at all, it must be less than 1/10,000th of the proportion we see in our Sun. This is extremely low; the most compelling explanation is that it's a true relic of the Big Bang."

The results will be published in the journal Monthly Notices of the Royal Astronomical Society.

Robert and his team used two of Keck Observatory's instruments -- the Echellette Spectrograph and Imager (ESI) and the High-Resolution Echelle Spectrometer (HIRES) -- to observe the spectrum of a quasar behind the gas cloud.

The quasar, which emits a bright glow of material falling into a supermassive black hole, provides a light source against which the spectral shadows of the hydrogen in the gas cloud can be seen.

"We targeted quasars where previous researchers had only seen shadows from hydrogen and not from heavy elements in lower-quality spectra," says Robert. "This allowed us to discover such a rare fossil quickly with the precious time on Keck Observatory's twin telescopes."

The only two other fossil clouds known were discovered in 2011 by Professor Michele Fumagalli of Durham University, John O'Meara, formerly a professor at St. Michael's College and now the new Chief Scientist at Keck Observatory, and Professor J. Xavier Prochaska of the University of California, Santa Cruz; both Fumagalli and O'Meara are co-authors of this new research on the third fossil cloud.

"The first two were serendipitous discoveries, and we thought they were the tip of the iceberg. But no one has discovered anything similar -- they are clearly very rare and difficult to see. It's fantastic to finally discover one systematically," says O'Meara.

"It's now possible to survey for these fossil relics of the Big Bang," says Murphy. "That will tell us exactly how rare they are and help us understand how some gas formed stars and galaxies in the early universe, and why some didn't."

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New discovery pushes origin of feathers back by 70 million years

These are the four feather types: filaments, filament bunches, tufted filament, down feather. Scale bars for photos, are a-d: 100µm, 200µm, 500µm and 1mm).

An international team of palaeontologists, which includes the University of Bristol, has discovered that the flying reptiles, pterosaurs, actually had four kinds of feathers, and these are shared with dinosaurs -- pushing back the origin of feathers by some 70 million years.

Pterosaurs are the flying reptiles that lived side by side with dinosaurs, 230 to 66 million years ago. It has long been known that pterosaurs had some sort of furry covering often called 'pycnofibres', and it was presumed that it was fundamentally different to feathers of dinosaurs and birds.

In a new work published today in the journal Nature Ecology & Evolution, a team from Nanjing, Bristol, Cork, Beijing, Dublin, and Hong Kong show that pterosaurs had at least four types of feathers:

• simple filaments ('hairs')
• bundles of filaments,
• filaments with a tuft halfway down
• down feathers.

These four types are now also known from two major groups of dinosaurs -- the ornithischians, which were plant-eaters, and the theropods, which include the ancestors of birds.

Baoyu Jiang of Nanjing University, who led the research, said: "We went to Inner Mongolia to do fieldwork in the Daohugou Formation.

"We already knew that the sites had produced excellent specimens of pterosaurs with their pycnofibres preserved and I was sure we could learn more by careful study."

Zixiao Yang, also of Nanjing University, has studied the Daohugou localities and the pterosaurs as part of his PhD work. He said: "This was a fantastic opportunity to work on some amazing fossils.

"I was able to explore every corner of the specimens using high-powered microscopes, and we found many examples of all four feathers."

Maria McNamara of University College Cork, added: "Some critics have suggested that actually there is only one simple type of pycnofibre, but our studies show the different feather types are real.

"We focused on clear areas where the feathers did not overlap and where we could see their structure clearly. They even show fine details of melanosomes, which may have given the fluffy feathers a ginger colour."

Professor Mike Benton from the University of Bristol's School of Earth Sciences, said: "We ran some evolutionary analyses and they showed clearly that the pterosaur pycnofibres are feathers, just like those seen in modern birds and across various dinosaur groups.

"Despite careful searching, we couldn't find any anatomical evidence that the four pycnofibre types are in any way different from the feathers of birds and dinosaurs. Therefore, because they are the same, they must share an evolutionary origin, and that was about 250 million years ago, long before the origin of birds."

Birds have two types of advanced feathers used in flight and for body smoothing, the contour feathers with a hollow quill and barbs down both sides.

These are found only in birds and the theropod dinosaurs close to bird origins. But the other feather types of modern birds include monofilaments and down feathers, and these are seen much more widely across dinosaurs and pterosaurs.

The armoured dinosaurs and the giant sauropods probably did not have feathers, but they were likely suppressed, meaning they were prevented from growing, at least in the adults, just as hair is suppressed in whales, elephants, and hippos. Pigs are a classic example, where the piglets are covered with hair like little puppies, and then, as they grow, the hair growth is suppressed.

Professor Benton added: "This discovery has amazing implications for our understanding of the origin of feathers, but also for a major time of revolution of life on land.

"When feathers arose, about 250 million years ago, life was recovering from the devasting end-Permian mass extinction.

"Independent evidence shows that land vertebrates, including the ancestors of mammals and dinosaurs, had switched gait from sprawling to upright, had acquired different degrees of warm-bloodedness, and were generally living life at a faster pace.

"The mammal ancestors by then had hair, so likely the pterosaurs, dinosaurs and relatives had also acquired feathers to help insulate them.

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