Formation of a magnetar 6.5 billion light years away

Researchers used X-ray images like this one to identify the formation of a magnetar. Different colors represent different levels of X-ray energy detected by the Chandra X-Ray Observatory.

A University of Arkansas researcher is part of a team of astronomers who have identified an outburst of X-ray emission from a galaxy approximately 6.5 billion light years away, which is consistent with the merger of two neutron stars to form a magnetar -- a large neutron star with an extremely powerful magnetic field. Based on this observation, the researchers were able to calculate that mergers like this happen roughly 20 times per year in each region of a billion light years cubed.

The research team, which includes Bret Lehmer, assistant professor of physics at the University of Arkansas, analyzed data from the Chandra X-ray Observatory, NASA's flagship X-ray telescope.

The Chandra Deep Field-South survey includes more than 100 X-ray observations of a single area of the sky over a period of more than 16 years to collect information about galaxies throughout the universe. Lehmer, who has worked with the observatory for 15 years, collaborated with colleagues in China, Chile and the Netherlands, and at Pennsylvania State University and the University of Nevada. The study was published in Nature.

A neutron star is a small, very dense star, averaging around 12 miles in diameter. Neutron stars are formed by the collapse of a star massive enough to produce a supernova, but not massive enough to become a black hole. When two neutron stars merge to become a magnetar, the resulting magnetic field is 10 trillion times stronger than a kitchen magnet.

"Neutron stars are mysterious because the matter in them is so extremely dense and unlike anything reproduceable in a laboratory," Lehmer explained. "We do not yet have a good understanding of the physical state of the matter in neutron stars. Mergers involving neutron stars produce lots of unique data that gives us clues about the nature of neutron stars themselves and what happens when they collide."

A previous discovery of two neutron stars merging, which used gravitational waves and gamma rays to make the observation, gave astronomers new insight into these objects. The research team used this new information to look for patterns in Chandra Observatory's X-ray data that were consistent with what they learned about merging neutron stars.

The researchers found an outburst of X-rays in the data from the Chandra Deep Field-South survey. After ruling out other possible sources of the X-rays, they determined the signals came from the process of two neutron stars forming a magnetar.

"A key piece of evidence is how the signal changed over time," said Lehmer. "It had a bright phase that plateaued and then dropped off in a very specific way. That is exactly what you'd expect from a magnetar that is rapidly losing its magnetic field through radiation."

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Hubble peers at cosmic blue bauble

Messier 3: Containing an incredible half-million stars, this 8-billion-year-old cosmic bauble is one of the largest and brightest globular clusters ever discovered.

Globular clusters are inherently beautiful objects, but the subject of this NASA/ESA Hubble Space Telescope image, Messier 3, is commonly acknowledged to be one of the most beautiful of them all.

Containing an incredible half-million stars, this 8-billion-year-old cosmic bauble is one of the largest and brightest globular clusters ever discovered. However, what makes Messier 3 extra special is its unusually large population of variable stars -- stars that fluctuate in brightness over time. New variable stars continue to be discovered in this sparkling stellar nest to this day, but so far we know of 274, the highest number found in any globular cluster by far. At least 170 of these are of a special variety called RR Lyrae variables, which pulse with a period directly related to their intrinsic brightness. If astronomers know how bright a star truly is based on its mass and classification, and they know how bright it appears to be from our viewpoint here on Earth, they can thus work out its distance from us. For this reason, RR Lyrae stars are known as standard candles -- objects of known luminosity whose distance and position can be used to help us understand more about vast celestial distances and the scale of the cosmos.

Messier 3 also contains a relatively high number of so-called blue stragglers, which are shown quite clearly in this Hubble image. These are blue main sequence stars that appear to be young because they are bluer and more luminous than other stars in the cluster. As all stars in globular clusters are believed to have formed together and thus to be roughly the same age, only a difference in mass can give these stars a different color. A red, old star can appear bluer when it acquires more mass, for instance by stripping it from a nearby star. The extra mass changes it into a bluer star, which makes us think it is younger than it really is.

From Science Daily

One-third of cancer patients use complementary and alternative medicine

A stunning one-third of people with a cancer diagnosis use complementary and alternative medicines such as meditation, yoga, acupuncture, herbal medicine, and supplements.

UT Southwestern Medical Center's Dr. Nina Sanford made the discovery that's now drawing renewed attention to habits she said cancer patients must disclose during treatment. Dr. Sanford is an Assistant Professor of Radiation Oncology who specializes in and treats cancers of the gastrointestinal tract.

Herbal supplements were the most common alternative medicine and chiropractic, or osteopathic manipulation, was the second most common, according to Dr. Sanford's analysis of data from the Centers for Disease Control and Prevention's National Health Interview Survey. Her findings were published in the journal JAMA Oncology.

"Younger patients are more likely to use complementary and alternative medicines and women were more likely to, but I would have thought more people would tell their doctors," Dr. Sanford said, referring to the finding that 29 percent of people who use complementary and alternative medicine did not tell their physicians. Many survey respondents said they did not say anything because their doctors did not ask, or they did not think their doctors needed to know.

Dr. Sanford and other cancer specialists agree this is concerning, especially in the case of herbal supplements.

"You don't know what's in them," Dr. Sanford said. "Some of these supplements are kind of a mishmash of different things. Unless we know what's in them, I would recommend patients avoid using them during radiation because there's likely not data on certain supplements, which could interfere with treatment. With radiation specifically, there is concern that very high levels of antioxidants could make radiation less effective."

Dr. David Gerber, a lung cancer specialist and a Professor of Internal Medicine and Population and Data Sciences at UTSW, said physicians need to know if their patients use herbal supplements because they can completely throw off traditional cancer treatments.

"They may interact with the medicines we're giving them, and through that interaction it could alter the level of the medicine in the patient," he said. "If the levels get too high, then toxicities increase, and if the levels get too low, the efficacy would drop."

Nancy Myers wanted to use supplements during her 2015-2017 cancer treatments, but she ran it by her doctors first.

"I would ask the physician, 'Could I?' and everyone said, 'No, we don't know how that interacts with your conventional medicine,' so I respected that," the 47-year-old mother of four said. Only after treatment did she start taking turmeric, omega-3, vitamin D, and vitamin B6.

"I have plenty of friends in this cancer journey who I've met who take supplements. A lady I met recently takes 75 supplements a day. It takes her two hours to package her supplements every week," she said.

Ms. Myers said every person in her cancer support group uses some kind of alternative medicine. In addition to supplements, she practices meditation and yoga with guidance from a smartphone app.

"It's what we can control. We can't control the whole cancer," she said. "It helps because it takes your mind off just thinking about it."

She said she knows of some people with cancer who use only alternative medicine -- and no traditional medical treatments. Dr. Sanford said this is a dangerous approach that could be fatal. The most famous case of this was Apple founder Steve Jobs, who reportedly used special diets, acupuncture, and other alternatives after receiving a diagnosis of pancreatic cancer. He turned to traditional medicine late in his battle with cancer and died in 2011.

While doctors are highly cautious about the use of herbs and other supplements during treatment, they are much more open to meditation and yoga as practices that can help patients cope with the shock of a cancer diagnosis and the stress of chemotherapy, radiation, and surgery.

"We strongly advise patients to stay active and engage in exercise during treatment," Dr. Sanford said. "A common side effect of radiation is fatigue. I let the patients know that the patients who feel the most fatigue are the ones who are the most sedentary and that those who are doing exercise are the ones who frequently have the most energy."

Belindy Sarembock, 53, of Dallas, said she practiced yoga during her treatments for breast cancer. She started the classes with skepticism and quickly became convinced of the benefits.

"I was one who would have laughed at yoga before breast cancer, but now it just helps me so much," she said. "It's just so relaxing, I just feel so good after I leave. It's just so peaceful. For your body, I can't think of anything better than that."

She said she had neuropathy or nerve damage from chemotherapy, and yoga almost immediately took the pain away.

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Earliest life may have arisen in ponds, not oceans

Did life originate in shallow ponds?

Primitive ponds may have provided a suitable environment for brewing up Earth's first life forms, more so than oceans, a new MIT study finds.

Researchers report that shallow bodies of water, on the order of 10 centimeters deep, could have held high concentrations of what many scientists believe to be a key ingredient for jump-starting life on Earth: nitrogen.

In shallow ponds, nitrogen, in the form of nitrogenous oxides, would have had a good chance of accumulating enough to react with other compounds and give rise to the first living organisms. In much deeper oceans, nitrogen would have had a harder time establishing a significant, life-catalyzing presence, the researchers say.

"Our overall message is, if you think the origin of life required fixed nitrogen, as many people do, then it's tough to have the origin of life happen in the ocean," says lead author Sukrit Ranjan, a postdoc in MIT's Department of Earth, Atmospheric and Planetary Sciences (EAPS). "It's much easier to have that happen in a pond."

Ranjan and his colleagues have published their results today in the journal Geochemistry, Geophysics, Geosystems. The paper's co-authors are Andrew Babbin, the Doherty Assistant Professor in Ocean Utilization in EAPS, along with Zoe Todd and Dimitar Sasselov of Harvard University, and Paul Rimmer at Cambridge University.

Breaking a bond

If primitive life indeed sprang from a key reaction involving nitrogen, there are two ways in which scientists believe this could have happened. The first hypothesis involves the deep ocean, where nitrogen, in the form of nitrogenous oxides, could have reacted with carbon dioxide bubbling forth from hydrothermal vents, to form life's first molecular building blocks.

The second nitrogen-based hypothesis for the origin of life involves RNA -- ribonucleic acid, a molecule that today helps encode our genetic information. In its primitive form, RNA was likely a free-floating molecule. When in contact with nitrogenous oxides, some scientists believe, RNA could have been chemically induced to form the first molecular chains of life. This process of RNA formation could have occurred in either the oceans or in shallow lakes and ponds.

Nitrogenous oxides were likely deposited in bodies of water, including oceans and ponds, as remnants of the breakdown of nitrogen in Earth's atmosphere. Atmospheric nitrogen consists of two nitrogen molecules, linked via a strong triple bond, that can only be broken by an extremely energetic event -- namely, lightning.

"Lightning is like a really intense bomb going off," Ranjan says. "It produces enough energy that it breaks that triple bond in our atmospheric nitrogen gas, to produce nitrogenous oxides that can then rain down into water bodies."

Scientists believe that there could have been enough lightning crackling through the early atmosphere to produce an abundance of nitrogenous oxides to fuel the origin of life in the ocean. Ranjan says scientists have assumed that this supply of lightning-generated nitrogenous oxides was relatively stable once the compounds entered the oceans.

However, in this new study, he identifies two significant "sinks," or effects that could have destroyed a significant portion of nitrogenous oxides, particularly in the oceans. He and his colleagues looked through the scientific literature and found that nitrogenous oxides in water can be broken down via interactions with the sun's ultraviolet light, and also with dissolved iron sloughed off from primitive oceanic rocks.

Ranjan says both ultraviolet light and dissolved iron could have destroyed a significant portion of nitrogenous oxides in the ocean, sending the compounds back into the atmosphere as gaseous nitrogen.

"We showed that if you include these two new sinks that people hadn't thought about before, that suppresses the concentrations of nitrogenous oxides in the ocean by a factor of 1,000, relative to what people calculated before," Ranjan says.

"Building a cathedral"

In the ocean, ultraviolet light and dissolved iron would have made nitrogenous oxides far less available for synthesizing living organisms. In shallow ponds, however, life would have had a better chance to take hold. That's mainly because ponds have much less volume over which compounds can be diluted. As a result, nitrogenous oxides would have built up to much higher concentrations in ponds. Any "sinks," such as UV light and dissolved iron, would have had less of an effect on the compound's overall concentrations.

Ranjan says the more shallow the pond, the greater the chance nitrogenous oxides would have had to interact with other molecules, and particularly RNA, to catalyze the first living organisms.

"These ponds could have been from 10 to 100 centimeters deep, with a surface area of tens of square meters or larger," Ranjan says. "They would have been similar to Don Juan Pond in Antarctica today, which has a summer seasonal depth of about 10 centimeters."

That may not seem like a significant body of water, but he says that's precisely the point: In environments any deeper or larger, nitrogenous oxides would simply have been too diluted, precluding any participation in origin-of-life chemistry. Other groups have estimated that, around 3.9 billion years ago, just before the first signs of life appeared on Earth, there may have been about 500 square kilometers of shallow ponds and lakes worldwide.

"That's utterly tiny, compared to the amount of lake area we have today," Ranjan says. "However, relative to the amount of surface area prebiotic chemists postulate is required to get life started, it's quite adequate."

The debate over whether life originated in ponds versus oceans is not quite resolved, but Ranjan says the new study provides one convincing piece of evidence for the former.

Read more at Science Daily

World's fastest hydrogen sensor could pave the way for clean hydrogen energy

Fast and accurate sensors will be crucial in a sustainable society where hydrogen is an energy carrier. Hydrogen gas is produced by water that is split with the help of electricity from wind power or solar energy. The sensors are needed both when the hydrogen is produced and when it is used, for example in cars powered by a fuel cell. In order to avoid the formation of flammable and explosive gas when hydrogen is mixed with air, the hydrogen sensors need to be able to quickly detect leaks.

Hydrogen is a clean and renewable energy carrier that can power vehicles, with water as the only emission. Unfortunately, hydrogen gas is highly flammable when mixed with air, so very efficient and effective sensors are needed. Now, researchers from Chalmers University of Technology, Sweden, present the first hydrogen sensors ever to meet the future performance targets for use in hydrogen powered vehicles.

The researchers' ground-breaking results were recently published in the scientific journal Nature Materials. The discovery is an optical nanosensor encapsulated in a plastic material. The sensor works based on an optical phenomenon -- a plasmon -- which occurs when metal nanoparticles are illuminated and capture visible light. The sensor simply changes colour when the amount of hydrogen in the environment changes.

The plastic around the tiny sensor is not just for protection, but functions as a key component. It increases the sensor's response time by accelerating the uptake of the hydrogen gas molecules into the metal particles where they can be detected. At the same time, the plastic acts as an effective barrier to the environment, preventing any other molecules from entering and deactivating the sensor. The sensor can therefore work both highly efficiently and undisturbed, enabling it to meet the rigorous demands of the automotive industry -- to be capable of detecting 0.1 percent hydrogen in the air in less than a second.

"We have not only developed the world's fastest hydrogen sensor, but also a sensor that is stable over time and does not deactivate. Unlike today's hydrogen sensors, our solution does not need to be recalibrated as often, as it is protected by the plastic," says Ferry Nugroho, a researcher at the Department of Physics at Chalmers.

It was during his time as a PhD student that Ferry Nugroho and his supervisor Christoph Langhammer realised that they were on to something big. After reading a scientific article stating that no one had yet succeeded in achieving the strict response time requirements imposed on hydrogen sensors for future hydrogen cars, they tested their own sensor. They realised that they were only one second from the target -- without even trying to optimise it. The plastic, originally intended primarily as a barrier, did the job better than they could have imagined, by also making the sensor faster. The discovery led to an intense period of experimental and theoretical work.

"In that situation, there was no stopping us. We wanted to find the ultimate combination of nanoparticles and plastic, understand how they worked together and what made it so fast. Our hard work yielded results. Within just a few months, we achieved the required response time as well as the basic theoretical understanding of what facilitates it," says Ferry Nugroho.

Detecting hydrogen is challenging in many ways. The gas is invisible and odourless, but volatile and extremely flammable. It requires only four percent hydrogen in the air to produce oxyhydrogen gas, sometimes known as knallgas, which ignites at the smallest spark. In order for hydrogen cars and the associated infrastructure of the future to be sufficiently safe, it must therefore be possible to detect extremely small amounts of hydrogen in the air. The sensors need to be quick enough that leaks can be rapidly detected before a fire occurs.

"It feels great to be presenting a sensor that can hopefully be a part of a major breakthrough for hydrogen-powered vehicles. The interest we see in the fuel cell industry is inspiring," says Christoph Langhammer, Professor at Chalmers Department of Physics.

Although the aim is primarily to use hydrogen as an energy carrier, the sensor also presents other possibilities. Highly efficient hydrogen sensors are needed in the electricity network industry, the chemical and nuclear power industry, and can also help improve medical diagnostics.

"The amount of hydrogen gas in our breath can provide answers to, for example, inflammations and food intolerances. We hope that our results can be used on a broad front. This is so much more than a scientific publication," says Christoph Langhammer.

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Ice Ages occur when tropical islands and continents collide

Some 445 million years ago, the Eastern US (extreme left) sat in the tropics, where an island arc-continental collision created the Appalachian Mountains. That collision uplifted rocks that absorbed carbon dioxide, resulting in an ice age that lasted millions of years.

University of California scientists think they know why Earth's generally warm and balmy climate over the past billion years has occasionally been interrupted by cold snaps that enshroud the poles with ice and occasionally turn the planet into a snowball.

The key trigger, they say, is mountain formation in the tropics as continental land masses collide with volcanic island arcs, such as the Aleutian Islands chain in Alaska.

Earth's climate is, to a large degree, driven by the amount of carbon dioxide in the atmosphere, which traps heat and warms the planet. While fossil fuel burning since the Industrial Revolution has driven CO2 levels to heights not seen in 3 million years, CO2 levels have been even higher in Earth's past, coinciding with warm periods when no major ice sheets existed.

In fact, Earth's default climate seems to be warm and balmy. Periods with no glaciers dominated for three-quarters of the past 1 billion years.

Yet, half a dozen ice ages chilled Earth during that time, two of them severe enough to turn the planet into a Snowball Earth with ice covering much of the surface. What caused these frigid interludes?

In a study appearing in this week's edition of the journal Science, the team concludes that when volcanic arcs collide with continents in the tropics -- an inevitable consequence of the planet's constantly moving tectonic plates -- they trigger global cooling, resulting in a glacial climate with extensive ice caps.

Such a collision is going on now as parts of the Indonesian archipelago are pushed upward into mountains on the northern margin of Australia. The result is that there are mountains containing rocks known as ophiolites that have a high capacity to remove carbon from the atmosphere. Over geologic time periods, there is a balancing act between the CO2 emitted from volcanoes and CO2 consumed through chemical reactions with rocks. Rocks with abundant calcium and magnesium, such as ophiolites, are the most efficient at consuming CO2. When these elements are liberated from rocks, they combine with CO2 and make their way to the ocean, where they form limestone, locking CO2 into rock, where it remains for millions of years.

"Earth has a long-running carbon sequestration program," said UC Berkeley's Nicholas Swanson-Hysell, an assistant professor of earth and planetary science who designed the study with Francis Macdonald, a professor in the Department of Earth Science at UC Santa Barbara. "We know that these processes keep Earth's climate in balance, but determining what causes shifts between non-glacial and glacial climates on million-year timescales is a long-standing puzzle."

Unfortunately for Earth's future, the geologic processes that consume CO2 are slow and unable to contend with the massive CO2 emissions that result from the burning of oil, coal and natural gas. Over millennia, Earth's natural carbon sequestration program will restore balance, Swanson-Hysell said, but this will be a long wait for modern civilization, which has been so successful in Earth's current, cooler climate.

The Appalachians came with a major freeze

In 2017, Swanson-Hysell and Macdonald proposed that a major ice age 445 million years ago was triggered by a collision similar to that occurring today in Indonesia. That collision took place during the first phase of Appalachian mountain-building, when the present-day eastern U.S. was located in the tropics. In the warm and wet tropics, the weathering reactions that ultimately sequester carbon are even more efficient, which resulted in less CO2 in the atmosphere and a cooler planet for millions of years. The UC researchers' work built on a similar proposal by Macdonald and Oliver Jagoutz of MIT that such processes were important for cooling over the past 90 million years.

The new study strengthens the link between such tropical collisions and global climate and was conducted by Swanson-Hysell, Macdonald and Jagoutz, along with UC Berkeley graduate student Yuem Park and Lorraine Lisiecki of UC Santa Barbara.

In the current research, the Berkeley/Santa Barbara/MIT team used state-of-the-art models of Earth's paleogeography to reconstruct the position of such mountain-building events over the last half-billion years. They found that all three major ice ages over this time had been preceded by volcanic arc-continent collisions in the tropics, and that no collisions outside the tropics triggered an ice age.

"While we thought this process was important, the relationship between such environments in the tropics and glacial climate was clearer than we expected," said Swanson-Hysell.

The team's theory also explains why ice ages come to an end. As such collisions grind to a halt and less rock is exposed, or as the rocks drift out of the tropical rain belt, carbon sequestration becomes less efficient, CO2 levels rise as volcanic outgassing continues and Earth once again warms into a non-glacial climate.

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Yukon warmest it has been in 13,600 years

A peat plateau on the Dempster Highway with standing pools with bright green algal mats and a spectacular backdrop featuring the boreal forest.

A study from U of T Mississauga uses new research techniques to reveal alarming information about climate change in Canada's north. A study published in Nature Communications confirms that recent climate warming in the central Yukon region has surpassed the warmest temperatures experienced in the previous 13,600 years, a finding that could have important implications in the context of current global warming trends.

Paleoclimatologist and lead author Trevor Porter studies climate indicators such as water isotopes, tree rings and plant waxes for signs of climate patterns in the Holocene, a period of time that spans the past 11,700 years. In glaciated regions, paleoclimate research often relies on water isotopes measured from ice core samples taken from glaciers, but in the central Yukon where glaciers have long since receded, researchers must rely on other indicators such as plant pollen and small winged insects known as midges preserved in layers of lake sediment. Pollen and midges act as proxies for ancient temperatures but sometimes offer conflicting information.

In a first for the field, Porter and his colleagues used radiocarbon dating and water isotopes preserved in permafrost beneath a central Yukon peatland to reconstruct summer temperatures over the last 13,600 years. Each summer, new peat moss accumulates at the surface, and the top of permafrost, which lies at a constant depth of 58 cm below ground, adjusts to the new surface. It simultaneously preserves precipitation that filtered through the ground and froze at the top of permafrost during previous summers. "Each centimeter of permafrost holds roughly 20 to 30 years of precipitation, which settles into well-blended layers of information," Porter says. "Water isotope records from ice cores are one of the most valued climate proxies but can only be developed in glaciated regions. This project demonstrates that we can develop ice core-like records in non-glaciated permafrost regions. This type of permafrost offers a unique archive for water isotopes that could be used to advance our understanding of Holocene climate change in other northern regions, which would be a major benefit to the climate science community."

The results of the permafrost analysis confirms information provided by previous midge studies, and shows that early Holocene summers in the central Yukon were mostly warmer than the typical Holocene summer. The study further concludes that industrial-era warming has led to current summer temperatures that are unprecedented in the Holocene context, and exceeds all previous maximum temperatures by nearly 2°C.

"When compared with climate reconstructions from other northern areas, our data confirm that this region has been warming at an exceptional rate," Porter says. "We know, based on recent historical climate data, that this area has warmed up more than other high-latitude regions. This

region has experienced warming of just over 2ºC over the past century, which is above the global average and above the average of the Arctic region in general."

"Summer warming has major implications for permafrost landscapes. When temperatures go up, ice-rich permafrost can thaw, become unstable, and previously frozen soil carbon can be released to the atmosphere as carbon dioxide by microbes," Porter says, noting that the region experienced a deep thaw of permafrost roughly 9,000 years ago. "Deep permafrost thaw events did occur in this region in the early Holocene, a time we now know was relatively warm compared to the Holocene average but not nearly as warm as today. This implies that ice-rich permafrost in this region is currently vulnerable to similar thaw events."

"We're seeing the evidence right now that climate warming is destabilizing permafrost in northern Canada and releasing greenhouse gases," he says "This is potentially the new normal and, if it accelerates in the near future, it threatens to further amplify global climate change."

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Archaeologists identify first prehistoric figurative cave art in Balkans

Digital tracing of Bison featured in rock art.

An international team, led by an archaeologist from the University of Southampton and the University of Bordeaux, has revealed the first example of Palaeolithic figurative cave art found in the Balkan Peninsula.

Dr Aitor Ruiz-Redondo worked with researchers from the universities of Cantabria (Spain), Newfoundland (Canada), Zagreb (Croatia) and the Archaeological Museum of Istria (Croatia) to study the paintings, which could be up to 34,000 years old.

The cave art was first discovered in 2010 in Romualdova Pe?ina ('Romuald's cave') at Istria in Croatia, when Darko Komšo, Director of the Archaeological Museum of Istria, noticed the existence of the remains of a red colour in a deep part of the cave.

Following his discovery, the team led by Dr Ruiz-Redondo and funded by the French State and the Archaeological Museum of Istria, with the support of Natura Histrica, undertook a detailed analysis of the paintings and their archaeological context.

This led to the identification of several figurative paintings, including a bison, an ibex and two possible anthropomorphic figures, confirming the Palaeolithic age of the artworks. Furthermore, an excavation made in the ground below these paintings led to the discovery of a number of Palaeolithic age remains; a flint tool, an ochre crayon and several fragments of charcoal.

Radiocarbon dating of these objects show an estimated age of around 17,000 years and other indirect data suggest the paintings date to an even earlier period -- at around 34,000-31,000 years ago. Further research will be conducted in order to establish the precise age of the rock art.

Findings are published in the journal Antiquity.

This discovery expands the so far sparse register of Palaeolithic art in south east Europe. It makes Romualdova Pe?ina the first site where figurative Palaeolithic rock art has been discovered in this area. Together with Badanj in Bosnia and Herzegovina, the two are the only examples of rock art from the Palaeolithic period in the Balkans.

Dr Aitor Ruiz-Redondo, a British Academy-funded Newton International Fellow at the University of Southampton and postdoctoral researcher at the University of Bordeaux, said: "The importance of this finding is remarkable and sheds a new light on the understanding of Palaeolithic art in the territory of Croatia and the Balkan Peninsula, as well as its relationship with simultaneous phenomena throughout Europe."

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Unusual phenomenon in clouds triggers lightning flash

The lightning seen here starts out deep inside the cloud where scientists continue to study its first moments. In their study, UNH researchers observed a possible new way that lightning forms called "fast negative breakdown."

In a first-of-its-kind observation, researchers from the University of New Hampshire Space Science Center have documented a unique event that occurs in clouds before a lightning flash happens. Their observation, called "fast negative breakdown," documents a new possible way for lightning to form and is the opposite of the current scientific view of how air carries electricity in thunderstorms.

"This is the first time fast negative breakdown has ever been observed, so it's very exciting," said Ningyu Liu, professor of physics. "Despite over 250 years of research, how lightning begins is still a mystery. The process was totally unexpected and gives us more insight into how lightning starts and spreads."

Their finding, published in the journal Nature Communications, is another step toward answering the question of how lightning begins. Recently, the problem of lightning initiation seemed to be solved with the discovery of "fast positive breakdown" of air, which matched the theory long held by lightning researchers. Fast positive breakdown involves the downward development of a pathway in the cloud, moving from the positive charge at the top of the cloud to the negative charge in the middle of the cloud. The pathway forms at one-fifth the speed of light and can trigger lightning. However, the newly reported observation of fast negative breakdown shows that an upward pathway -- going in the opposite direction and just as fast -- can be created in a thundercloud, indicating there's another way to start electricity in the air. Ultimately, this provides scientists with a new view of what's possible inside a storm cloud.

"These findings indicate that lightning creation within a cloud might be more bidirectional than we originally thought," said Julia Tilles, a doctoral candidate in the UNH Space Science Center.

In collaboration with a lightning research team from New Mexico Institute of Mining and Technology, the researchers documented fast negative breakdown in a Florida lightning storm at Kennedy Space Center using radio waves originating deep inside the storm clouds. An array of ground-based antennas picked up the radio waves, which then allowed researchers to create a highly detailed image of the radio sources and identify this unusual phenomenon.

Researchers continue to develop images from the data and hope to learn more about how often fast negative breakdown events occur and what fraction of them can initiate an actual lightning flash.

From Science Daily

Ancient 'Texas Serengeti' had elephant-like animals, rhinos, alligators and more

Fossilized skull parts from ancient elephant relatives in the collections of the Jackson School Museum of Earth History. The skull of a shovel-jawed gomphothere (pictured on bottom) collected by Great Depression-era fossil hunters is still wrapped in its field jacket.

During the Great Depression, some unemployed Texans were put to work as fossil hunters. The workers retrieved tens of thousands of specimens that have been studied in small bits and pieces while stored in the state collections of The University of Texas at Austin for the past 80 years.

Now, decades after they were first collected, a UT researcher has studied and identified an extensive collection of fossils from dig sites near Beeville, Texas, and found that the fauna make up a veritable "Texas Serengeti" -- with specimens including elephant-like animals, rhinos, alligators, antelopes, camels, 12 types of horses and several species of carnivores. In total, the fossil trove contains nearly 4,000 specimens representing 50 animal species, all of which roamed the Texas Gulf Coast 11 million to 12 million years ago.

A paper describing these fossils, their collection history and geologic setting was published April 11 in the journal Palaeontologia Electronica.

"It's the most representative collection of life from this time period of Earth history along the Texas Coastal Plain," said Steven May, the research associate at the UT Jackson School of Geosciences who studied the fossils and authored the paper.

In addition to shedding light on the inhabitants of an ancient Texas ecosystem, the collection is also valuable because of its fossil firsts. They include a new genus of gomphothere, an extinct relative of elephants with a shovel-like lower jaw, and the oldest fossils of the American alligator and an extinct relative of modern dogs.

The fossils came into the university's collection as part of the State-Wide Paleontologic-Mineralogic Survey that was funded by the Works Progress Administration (WPA), a federal agency that provided work to millions of Americans during the Great Depression. From 1939 to 1941, the agency partnered with the UT Bureau of Economic Geology, which supervised the work and organized field units for collecting fossils and minerals across the state.

Despite lasting only three years, the survey found and excavated thousands of fossils from across Texas including four dig sites in Bee and Live Oak counties, with the majority of their finds housed in what is now the Texas Vertebrate Paleontology Collections at the Jackson School Museum of Earth History. Over the years, a number of scientific papers have been published on select groups of WPA specimens. But May's paper is the first to study the entire fauna.

This extensive collection of fossils is helping to fill in gaps about the state's ancient environment, said Matthew Brown, the director of the museum's vertebrate paleontology collections.

The emphasis on big mammals is due in large part to the collection practices of the fossil hunters, most of whom were not formally trained in paleontology. Large tusks, teeth and skulls were easier to spot -- and more exciting to find -- than bones left by small species.

"They collected the big, obvious stuff," May said. "But that doesn't fully represent the incredible diversity of the Miocene environment along the Texas Coastal Plain."

In order to account for gaps in the collection, May tracked down the original dig sites so he could screen for tiny fossils such as rodent teeth. One of the sites was on a ranch near Beeville owned by John Blackburn. Using aerial photography and notes from the WPA program stored in the university's archives, May and the research team were able to track down the exact spot of an original dig site.

"We're thrilled to be a part of something that was started in 1939," Blackburn said. "It's been a privilege to work with UT and the team involved, and we hope that the project can help bring additional research opportunities."

Scores of WPA-era fossils in the UT collections are still secured in plaster field jackets, waiting to be unpacked for future research projects. Lab managers Deborah Wagner and Kenneth Bader are supervising their preparation, which includes teaching UT students fossil prep skills so they can pick up where the WPA workers left off.

Wagner said that the advantage of unpacking fossils decades later is that they are able to apply modern research techniques that scientists from past eras wouldn't have dreamed possible.

"We are able to preserve more detailed anatomy and answer questions that require higher resolution data," she said.

Read more at Science Daily

New species of early human found in the Philippines

Professor Philip Piper from the ANU School of Archaeology and Anthropology inspects the cast of a hominin third metatarsal discovered in 2007. The bone is from a new species of hominin.

An international team of researchers have uncovered the remains of a new species of human in the Philippines, proving the region played a key role in hominin evolutionary history. The new species, Homo luzonensis is named after Luzon Island, where the more than 50,000 year old fossils were found during excavations at Callao Cave.

Co-author and a lead member of the team, Professor Philip Piper from The Australian National University (ANU) says the findings represent a major breakthrough in our understanding of human evolution across Southeast Asia.

The researchers uncovered the remains of at least two adults and one juvenile within the same archaeological deposits.

"The fossil remains included adult finger and toe bones, as well as teeth. We also recovered a child's femur. There are some really interesting features -- for example, the teeth are really small," Professor Piper said.

"The size of the teeth generally, though not always, reflect the overall body-size of a mammal, so we think Homo luzonensis was probably relatively small. Exactly how small we don't know yet. We would need to find some skeletal elements from which we could measure body-size more precisely" Professor Piper said.

"It's quite incredible, the extremities, that is the hand and feet bones are remarkably Australopithecine-like. The Australopithecines last walked the earth in Africa about 2 million years ago and are considered to be the ancestors of the Homo group, which includes modern humans.

"So, the question is whether some of these features evolved as adaptations to island life, or whether they are anatomical traits passed down to Homo luzonensis from their ancestors over the preceding 2 million years."

While there are still plenty of questions around the origins of Homo luzonensis, and their longevity on the island of Luzon, recent excavations near Callao Cave produced evidence of a butchered rhinoceros and stone tools dating to around 700,000 years ago.

"No hominin fossils were recovered, but this does provide a timeframe for a hominin presence on Luzon. Whether it was Homo luzonensis butchering and eating the rhinoceros remains to be seen," Professor Piper said.

"It makes the whole region really significant. The Philippines is made up of a group of large islands that have been separated long enough to have potentially facilitated archipelago speciation. There is no reason why archaeological research in the Philippines couldn't discover several species of hominin. It's probably just a matter of time."

Homo luzonensis shares some unique skeletal features with the famous Homo floresiensis or 'the hobbit', discovered on the island of Flores to the south east of the Philippine archipelago.

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More than 90% of glacier volume in the Alps could be lost by 2100

Gorner glacier at the end of the summer of 2017. The glacier is located in the Monte Rosa massif and is the second largest glacier of the European Alps.

The study, by a team of researchers in Switzerland, provides the most up-to-date and detailed estimates of the future of all glaciers in the Alps, around 4000. It projects large changes to occur in the coming decades: from 2017 to 2050, about 50% of glacier volume will disappear, largely independently of how much we cut our greenhouse gas emissions.

After 2050, "the future evolution of glaciers will strongly depend on how the climate will evolve," says study-leader Harry Zekollari, a researcher at ETH Zurich and the Swiss Federal Institute for Forest, Snow and Landscape Research, now at Delft University of Technology in the Netherlands. "In case of a more limited warming, a far more substantial part of the glaciers could be saved," he says.

Glacier retreat would have a large impact on the Alps since glaciers are an important part of the region's ecosystem, landscape and economy. They attract tourists to the mountain ranges and act as natural fresh water reservoirs. Glaciers provide a source of water for fauna and flora, as well as for agriculture and hydroelectricity, which is especially important in warm and dry periods.

To find out how Alpine glaciers would manage in a warming world, Zekollari and his co-authors used new computer models (combining ice flow and melt processes) and observational data to study how each of these ice bodies would change in the future for different emission scenarios. They used 2017 as their 'present day' reference, a year when Alpine glaciers had a total volume of about 100 cubic kilometres.

Under a scenario implying limited warming, called RCP2.6, emissions of greenhouse gases would peak in the next few years and then decline rapidly, keeping the level of added warming at the end of the century below 2°C since pre-industrial levels. In this case, Alpine glaciers would be reduced to about 37 cubic kilometres by 2100, just over one-third of their present-day volume.

Under the high-emissions scenario, corresponding to RCP8.5, emissions would continue to rise rapidly over the next few decades. "In this pessimistic case, the Alps will be mostly ice free by 2100, with only isolated ice patches remaining at high elevation, representing 5% or less of the present-day ice volume," says Matthias Huss, a researcher at ETH Zurich and co-author of The Cryosphere study. Global emissions are currently just above what is projected by this scenario.

The Alps would lose about 50% of their present glacier volume by 2050 in all scenarios. A reason why volume loss is mostly independent of emissions until 2050 is that increases in mean global temperature with increasing greenhouse gases only become more pronounced in the second half of the century. Another reason is that glaciers at present have 'too much' ice: their volume, especially at lower elevations, still reflects the colder climate of the past because glaciers are slow at responding to changing climate conditions. Even if we manage to stop the climate from warming any further, keeping it at the level of the past 10 years, glaciers would still lose about 40% of their present-day volume by 2050 because of this "glacier response time," says Zekollari.

Read more at Science Daily

'Cthulhu' fossil reconstruction reveals monstrous relative of modern sea cucumbers

This is a 3D reconstruction of Sollasina cthulhu. Tube feet are shown in different colors.

An exceptionally-preserved fossil from Herefordshire in the UK has given new insights into the early evolution of sea cucumbers, the group that includes the sea pig and its relatives, according to a new article published today in the journal Proceedings of the Royal Society B.

Palaeontologists from the UK and USA created an accurate 3D computer reconstruction of the 430 million-year-old fossil which allowed them to identify it as a species new to science. They named the animal Sollasina cthulhu due to its resemblance to monsters from the fictional Cthulhu universe created by author H.P. Lovecraft.

Although the fossil is just 3 cm wide, its many long tentacles would have made it appear quite monstrous to other small sea creatures alive at the time. It is thought that these tentacles, or 'tube feet', were used to capture food and crawl over the seafloor.

Like other fossils from Herefordshire, Sollasina cthulhu was studied using a method that involved grinding it away, layer-by-layer, with a photograph taken at each stage. This produced hundreds of slice images, which were digitally reconstructed as a 'virtual fossil'.

This 3D reconstruction allowed palaeontologists to visualise an internal ring, which they interpreted as part of the water vascular system -- the system of fluid-filled canals used for feeding and movement in living sea cucumbers and their relatives.

Lead author, Dr Imran Rahman, Deputy Head of Research at Oxford University Museum of Natural History said:

"Sollasina belongs to an extinct group called the ophiocistioids, and this new material provides the first information on the group's internal structures. This includes an inner ring-like form that has never been described in the group before. We interpret this as the first evidence of the soft parts of the water vascular system in ophiocistioids."

The new fossil was incorporated into a computerized analysis of the evolutionary relationships of fossil sea cucumbers and sea urchins. The results showed that Sollasina and its relatives are most closely related to sea cucumbers, rather than sea urchins, shedding new light on the evolutionary history of the group.

Co-author Dr Jeffrey Thompson, Royal Society Newton International Fellow at University College London, said:

"We carried out a number of analyses to work out whether Sollasina was more closely related to sea cucumbers or sea urchins. To our surprise, the results suggest it was an ancient sea cucumber. This helps us understand the changes that occurred during the early evolution of the group, which ultimately gave rise to the slug-like forms we see today."

The fossil was described by an international team of researchers from Oxford University Museum of Natural History, University of Southern California, Yale University, University of Leicester, and Imperial College London. It represents one of many important finds recovered from the Herefordshire fossil site in the UK, which is famous for preserving both the soft as well as the hard parts of fossils.

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Tracking records of the oldest life forms on Earth

Rocks with banded iron formations and biosignatures - 1,900 million years old, Michigan, US (top left), 2,700 million years old, Ontario, Canada (bottom left) and 2,500 million years old, Karijini National Park, Western Australia (right).

The discovery provides a new characteristic 'biosignature' to track the remains of ancient life preserved in rocks which are significantly altered over billions of years and could help identify life elsewhere in the Solar System.

The research, published in two papers -- one in the Journal of the Geological Society and another in Earth and Planetary Science Letters -- solves the longstanding problem of how scientists can track records of life on Earth in highly metamorphosed rocks more than 3,700 million years old, with organic material often turning into the carbon-based mineral graphite.

In the first study, published in Earth and Planetary Science Letters, the team analysed ten rock samples of banded iron formations (BIF) from Canada, India, China, Finland, USA and Greenland spanning over 2,000 million years of history.

They argue that carbon preserved in graphite-like crystals -'graphitic carbon'- located alongside minerals such as apatite, which our teeth and bones are made of, and carbonate, are the biosignatures of the oldest life forms on Earth.

"Life on Earth is all carbon-based and over time, it decomposes into different substances, such as carbonate, apatite and oil. These become trapped in layers of sedimentary rock and eventually the oil becomes graphite during subsequent metamorphism in the crust," explained Dr Dominic Papineau (UCL Earth Sciences, Center for Planetary Sciences and the London Centre for Nanotechnology).

"Our discovery is important as it is hotly debated whether the association of graphite with apatite is indicative of a biological origin of the carbon found in ancient rocks. We now have multiple strands of evidence that these mineral associations are biological in banded iron formations. This has huge implications for how we determine the origin of carbon in samples of extra-terrestrial rocks returned from elsewhere in the Solar System."

The team investigated the composition of BIF rocks as they are almost always of Precambrian age (4,600 million years old to 541 million years old) and record information about the oldest environments on Earth.

For this, they analysed the composition of rocks ranging from 1,800 million years old to more than 3,800 million years old using a range of methods involving photons, electrons, and ions to characterise the composition of graphite and other minerals of potential biogenic origin.

"Previously, it was assumed that finding apatite and graphite together in ancient rocks was a rare occurrence but this study shows that it is commonplace in BIF across a range of rock metamorphic grades," said team member Dr Matthew Dodd (UCL Earth Sciences and the London Centre for Nanotechnology).

The apatite and graphite minerals are thought to have two possible origins: mineralised products of decayed biological organic matter, which includes the breakdown of molecules in oil at high temperatures, or formation through non-biological reactions which are relevant to the chemistry of how life arose from non-living matter.

By showing evidence for the widespread occurrence of graphitic carbon in apatite and carbonate in BIF along with its carbon-isotope composition, the researchers conclude that the minerals are most consistent with a biological origin from the remains of Earth's oldest life forms.

To investigate the extent to which high-temperature metamorphism causes a loss in molecular, elemental and isotope signatures from biological matter in rocks, they analysed the same minerals from a 1,850 million year old BIF rock in Michigan which had metamorphosed in 550 degree Celsius heat.

In this second study, published today in Journal of the Geological Society, the team show that several biosignatures are found in the graphitic carbon and the associated apatite, carbonate and clays.

They used a variety of high-tech instruments to detect traces of key molecules, elements, and carbon isotopes of graphite and combined this with several microscopy techniques to study tiny objects trapped in rocks which are invisible to the naked eye.

Together, all of their observations of the composition are consistent with an origin from decayed biomass, such as that of ancient animal fossils in museums, but which has been strongly altered by high temperatures.

"Our new data provide additional lines of evidence that graphite associated with apatite in BIF is most likely biological in origin. Moreover, by taking a range of observations from throughout the geological record, we resolve a long-standing controversy regarding the origin of isotopically light graphitic carbon with apatite in the oldest BIF," said Dr Papineau.

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Working together as a 'virtual telescope,' observatories around the world produce first direct images of a black hole

The Event Horizon Telescope (EHT) -- a planet-scale array of eight ground-based radio telescopes forged through international collaboration -- was designed to capture images of a black hole. In coordinated press conferences across the globe, EHT researchers revealed that they succeeded, unveiling the first direct visual evidence of the supermassive black hole in the centre of Messier 87 and its shadow.

An international team of over 200 astronomers, including scientists from MIT's Haystack Observatory, has captured the first direct images of a black hole. They accomplished this remarkable feat by coordinating the power of eight major radio observatories on four continents, to work together as a virtual, Earth-sized telescope.

In a series of papers published today in a special issue of Astrophysical Journal Letters (https://iopscience.iop.org/issue/2041-8205/875/1), the team has revealed four images of the supermassive black hole at the heart of Messier 87, or M87, a galaxy within the Virgo galaxy cluster, 55 million light years from Earth.

All four images show a central dark region surrounded by a ring of light that appears lopsided -- brighter on one side than the other.

Albert Einstein, in his theory of general relativity, predicted the existence of black holes, in the form of infinitely dense, compact regions in space, where gravity is so extreme that nothing, not even light, can escape from within. By definition, black holes are invisible. But if a black hole is surrounded by light-emitting material such as plasma, Einstein's equations predict that some of this material should create a "shadow," or an outline of the black hole and its boundary, also known as its event horizon.

Based on the new images of M87, the scientists believe they are seeing a black hole's shadow for the first time, in the form of the dark region at the center of each image.

Relativity predicts that the immense gravitational field will cause light to bend around the black hole, forming a bright ring around its silhouette, and will also cause the surrounding material to orbit around the object at close to light speed. The bright, lopsided ring in the new images offers visual confirmation of these effects: The material headed toward our vantage point as it rotates around appears brighter than the other side.

From these images, theorists and modelers on the team have determined that the black hole is about 6.5 billion times as massive as our sun. Slight differences between each of the four images suggest that material is zipping around the black hole at lightning speed.

"This black hole is much bigger than the orbit of Neptune, and Neptune takes 200 years to go around the sun," says Geoffrey Crew, a research scientist at Haystack Observatory. "With the M87 black hole being so massive, an orbiting planet would go around it within a week and be traveling at close to the speed of light."

"People tend to view the sky as something static, that things don't change in the heavens, or if they do, it's on timescales that are longer than a human lifetime," says Vincent Fish, a research scientist at Haystack Observatory. "But what we find for M87 is, at the very fine detail we have, objects change on the timescale of days. In the future, we can perhaps produce movies of these sources. Today we're seeing the starting frames."

"These remarkable new images of the M87 black hole prove that Einstein was right yet again," says Maria Zuber, MIT's vice president for research and the E.A. Griswold Professor of Geophysics in the Department of Earth, Atmospheric and Planetary Sciences. "The discovery was enabled by advances in digital systems at which Haystack engineers have long excelled."

"Nature was kind"

The images were taken by the Event Horizon Telescope, or EHT, a planet-scale array comprising eight radio telescopes, each in a remote, high-altitude environment, including the mountaintops of Hawaii, Spain's Sierra Nevada, the Chilean desert, and the Antarctic ice sheet.

On any given day, each telescope operates independently, observing astrophysical objects that emit faint radio waves. However, a black hole is infinitely smaller and darker than any other radio source in the sky. To see it clearly, astronomers need to use very short wavelengths -- in this case, 1.3 millimeters -- that can cut through the clouds of material between a black hole and the Earth.

Making a picture of a black hole also requires a magnification, or "angular resolution," equivalent to reading a text on a phone in New York from a sidewalk café in Paris. A telescope's angular resolution increases with the size of its receiving dish. However, even the largest radio telescopes on Earth are nowhere near big enough to see a black hole.

But when multiple radio telescopes, separated by very large distances, are synchronized and focused on a single source in the sky, they can operate as one very large radio dish, through a technique known as very long baseline interferometry, or VLBI. Their combined angular resolution as a result can be vastly improved.

For EHT, the eight participating telescopes summed up to a virtual radio dish as big as the Earth, with the ability to resolve an object down to 20 micro-arcseconds -- about 3 million times sharper than 20/20 vision. By a happy coincidence, that's about the precision required to view a black hole, according to Einstein's equations.

"Nature was kind to us, and gave us something just big enough to see by using state-of-the-art equipment and techniques," says Crew, co-leader of the EHT correlation working group and the ALMA Observatory VLBI team.

"Gobs of data"

On April 5, 2017, the EHT began observing M87. After consulting numerous weather forecasts, astronomers identified four nights that would produce clear conditions for all eight observatories -- a rare opportunity, during which they could work as one collective dish to observe the black hole.

In radio astronomy, telescopes detect radio waves, at frequencies that register incoming photons as a wave, with an amplitude and phase that's measured as a voltage. As they observed M87, every telescope took in streams of data in the form of voltages, represented as digital numbers.

"We're recording gobs of data -- petabytes of data for each station," Crew says.

In total, each telescope took in about one petabyte of data, equal to 1 million gigabytes. Each station recorded this enormous influx that onto several Mark6 units -- ultrafast data recorders that were originally developed at Haystack Observatory.

After the observing run ended, researchers at each station packed up the stack of hard drives and flew them via FedEx to Haystack Observatory, in Massachusetts, and Max Planck Institute for Radio Astronomy, in Germany. (Air transport was much faster than transmitting the data electronically.) At both locations, the data were played back into a highly specialized supercomputer called a correlator, which processed the data two streams at a time.

As each telescope occupies a different location on the EHT's virtual radio dish, it has a slightly different view of the object of interest -- in this case, M87. The data received by two separate telescopes may encode a similar signal of the black hole but also contain noise that's specific to the respective telescopes.

The correlator lines up data from every possible pair of the EHT's eight telescopes. From these comparisons, it mathematically weeds out the noise and picks out the black hole's signal. High-precision atomic clocks installed at every telescope time-stamp incoming data, enabling analysts to match up data streams after the fact.

"Precisely lining up the data streams and accounting for all kinds of subtle perturbations to the timing is one of the things that Haystack specializes in," says Colin Lonsdale, Haystack director and vice chair of the EHT directing board.

Teams at both Haystack and Max Planck then began the painstaking process of "correlating" the data, identifying a range of problems at the different telescopes, fixing them, and rerunning the correlation, until the data could be rigorously verified. Only then were the data released to four separate teams around the world, each tasked with generating an image from the data using independent techniques.

"It was the second week of June, and I remember I didn't sleep the night before the data was released, to be sure I was prepared," says Kazunori Akiyama, co-leader of the EHT imaging group and a postdoc working at Haystack.

All four imaging teams previously tested their algorithms on other astrophysical objects, making sure that their techniques would produce an accurate visual representation of the radio data. When the files were released, Akiyama and his colleagues immediately ran the data through their respective algorithms. Importantly, each team did so independently of the others, to avoid any group bias in the results.

"The first image our group produced was slightly messy, but we saw this ring-like emission, and I was so excited at that moment," Akiyama remembers. "But simultaneously I was worried that maybe I was the only person getting that black hole image."

His concern was short-lived. Soon afterward all four teams met at the Black Hole Initiative at Harvard University to compare images, and found, with some relief, and much cheering and applause, that they all produced the same, lopsided, ring-like structure -- the first direct images of a black hole.

"There have been ways to find signatures of black holes in astronomy, but this is the first time anyone's ever taken a picture of one," Crew says. "This is a watershed moment."

"A new era"

The idea for the EHT was conceived in the early 2000s by Sheperd Doeleman, who was leading a pioneering VLBI program at Haystack Observatory and now directs the EHT project as an astronomer at the Harvard-Smithsonian Center for Astrophysics. At the time, Haystack engineers were developing the digital back-ends, recorders, and correlator that could process the enormous datastreams that an array of disparate telescopes would receive.

"The concept of imaging a black hole has been around for decades," Lonsdale says. "But it was really the development of modern digital systems that got people thinking about radio astronomy as a way of actually doing it. More telescopes on mountaintops were being built, and the realization gradually came along that, hey, [imaging a black hole] isn't absolutely crazy."

In 2007, Doeleman's team put the EHT concept to the test, installing Haystack's recorders on three widely scattered radio telescopes and aiming them together at Sagittarius A*, the black hole at the center of our own galaxy.

"We didn't have enough dishes to make an image," recalls Fish, co-leader of the EHT science operations working group. "But we could see there was something there that's about the right size."

Today, the EHT has grown to an array of 11 observatories: ALMA, APEX, the Greenland Telescope, the IRAM 30-meter Telescope, the IRAM NOEMA Observatory, the Kitt Peak Telescope, the James Clerk Maxwell Telescope, the Large Millimeter Telescope Alfonso Serrano, the Submillimeter Array, the Submillimeter Telescope, and the South Pole Telescope.

Coordinating observations and analysis has involved over 200 scientists from around the world who make up the EHT collaboration, with 13 main institutions, including Haystack Observatory. Key funding was provided by the National Science Foundation, the European Research Council, and funding agencies in East Asia, including the Japan Society for the Promotion of Science. The telescopes contributing to this result were ALMA, APEX, the IRAM 30-meter telescope, the James Clerk Maxwell Telescope, the Large Millimeter Telescope Alfonso Serrano, the Submillimeter Array, the Submillimeter Telescope, and the South Pole Telescope.

More observatories are scheduled to join the EHT array, to sharpen the image of M87 as well as attempt to see through the dense material that lies between Earth and the center of our own galaxy, to the heart of Sagittarius A*.

"We've demonstrated that the EHT is the observatory to see a black hole on an event horizon scale," Akiyama says. "This is the dawn of a new era of black hole astrophysics."

Read more at Science Daily

Astronomers find evidence of a planet with a mass almost 13 times that of Jupiter

Brazilian researchers have identified robust signs of the existence of a giant object in the Cygnus constellation orbiting a binary system of a live star and a white dwarf.

In the past three decades, almost 4,000 planet-like objects have been discovered orbiting isolated stars outside the Solar System (exoplanets). Beginning in 2011, it was possible to use NASA's Kepler Space Telescope to observe the first exoplanets in orbit around young binary systems of two live stars with hydrogen still burning in their core.

Brazilian astronomers have now found the first evidence of the existence of an exoplanet orbiting an older or more evolved binary in which one of the two stars is dead.

The study resulted from a postdoctoral research project and a research internship abroad, both with scholarships from São Paulo Research Foundation -- FAPESP. Its findings have just been published in the Astronomical Journal.

Leonardo Andrade de Almeida, first author of the article, told as follow: "We succeeded in obtaining pretty solid evidence of the existence of a giant exoplanet with a mass almost 13 times that of Jupiter [the largest planet in the Solar System] in an evolved binary system. This is the first confirmation of an exoplanet in a system of this kind."

Almeida is currently a postdoctoral fellow of the Federal University of Rio Grande do Norte (UFRN), having conducted postdoctoral research at the University of São Paulo's Institute of Astronomy, Geophysics and Atmospheric Sciences (IAG-USP), where he was supervised by Professor Augusto Damineli, a coauthor of the study.

Clues followed by the researchers to discover the exoplanet in the evolved binary called KIC 10544976, located in the Cygnus constellation in the northern celestial hemisphere, included variations in eclipse timing (the time taken for each of the two stars to eclipse the other) and orbital period.

"Variations in the orbital period of a binary are due to gravitational attraction among the three objects, which orbit around a common center of mass," Almeida said.

Orbital period variations are not enough to prove the existence of a planet in the case of binaries, however, because binary stars' magnetic activity fluctuates periodically, just as the Sun's magnetic field changes polarity every 11 years, with turbulence and the number and size of sunspots peaking and then declining.

"Variations in the Sun's magnetic activity eventually cause a change in its magnetic field. The same is true of all isolated stars. In binaries, these variations also cause a change in orbital period due to what we call the Applegate mechanism," Almeida explained.

To refute the hypothesis that variations in the orbital period of KIC 10544976 were due only to magnetic activity, the researchers analyzed the effect of eclipse timing variation and the magnetic activity cycle of the binary's live star.

KIC 10544976 consists of a white dwarf, a dead low-mass star with a high surface temperature, and a red dwarf, a live (magnetically active) star with a small mass compared to that of our Sun and scant luminosity due to low energy output. The two stars were monitored by ground-based telescopes between 2005 and 2017 and by Kepler between 2009 and 2013, producing data minute by minute.

"The system is unique," Almeida said. "No similar system has enough data to let us calculate orbital period variation and magnetic cycle activity for the live star."

Using the Kepler data, they were able to estimate the magnetic cycle of the live star (red dwarf) based on the rate and energy of flares (large eruptions of electromagnetic radiation) and variability due to spots (regions of cooler surface temperature and hence darkness caused by different concentrations of magnetic field flux).

Analysis of the data showed that the red dwarf's magnetic activity cycle lasted 600 days, which is consistent with the magnetic cycles estimated for low-mass isolated stars. The binary's orbital period was estimated at 17 years.

"This completely refutes the hypothesis that orbital period variation is due to magnetic activity. The most plausible explanation is the presence of a giant planet orbiting the binary, with a mass approximately 13 times that of Jupiter," Almeida said.

Formation hypotheses

How the planet orbiting the binary was formed is unknown. One hypothesis is that it developed at the same time as the two stars billions of years ago. If so, it is a first-generation planet. Another hypothesis is that it formed out of the gas ejected during the death of the white dwarf, making it a second-generation planet.

Confirmation of its status as either a first- or second-generation planet and its direct detection as it orbits the binary could be obtained using the new generation of ground-based telescopes with primary mirrors exceeding 20 meters, including the Giant Magellan Telescope (GMT) installed in Chile's Atacama Desert. The GMT is expected to see first light in 2024.

FAPESP will invest US$40 million in the GMT, or approximately 4% of the telescope's estimated total cost. This investment will guarantee 4% of the telescope's operating time for studies by researchers from São Paulo State.

Read more at Science Daily

Woolly mammoths and Neanderthals may have shared genetic traits

Mammoth rendering.

A new Tel Aviv University study suggests that the genetic profiles of two extinct mammals with African ancestry -- woolly mammoths, elephant-like animals that evolved in the arctic peninsula of Eurasia around 600,000 years ago, and Neanderthals, highly skilled early humans who evolved in Europe around 400,000 years ago -- shared molecular characteristics of adaptation to cold environments.

The research attributes the human-elephant relationship during the Pleistocene epoch to their mutual ecology and shared living environments, in addition to other possible interactions between the two species. The study was led by Prof. Ran Barkai and Meidad Kislev of TAU's Department of Archaeology and Ancient Near Eastern Cultures and published on April 8 in Human Biology.

"Neanderthals and mammoths lived together in Europe during the Ice Age. The evidence suggests that Neanderthals hunted and ate mammoths for tens of thousands of years and were actually physically dependent on calories extracted from mammoths for their successful adaptation," says Prof. Barkai. "Neanderthals depended on mammoths for their very existence.

"They say you are what you eat. This was especially true of Neanderthals; they ate mammoths but were apparently also genetically similar to mammoths."

To assess the degree of resemblance between mammoth and Neanderthal genetic components, the archaeologists reviewed three case studies of relevant gene variants and alleles -- alternative forms of a gene that arise by mutation and are found at the same place on a chromosome -- associated with cold-climate adaptation found in the genomes of both woolly mammoths and Neanderthals.

The first case study outlined the mutual appearance of the LEPR gene, related to thermogenesis and the regulation of adipose tissue and fat storage throughout the body. The second case study engaged genes related to keratin protein activity in both species. The third case study focused on skin and hair pigmentation variants in the genes MC1R and SLC7A11.

"Our observations present the likelihood of resemblance between numerous molecular variants that resulted in similar cold-adapted epigenetic traits of two species, both of which evolved in Eurasia from an African ancestor," Kislev explains. "These remarkable findings offer supporting evidence for the contention regarding the nature of convergent evolution through molecular resemblance, in which similarities in genetic variants between adapted species are present.

"We believe these types of connections can be valuable for future evolutionary research. They're especially interesting when they involve other large-brained mammals, with long life spans, complex social behavior and their interactions in shared habitats with early humans."

According to the study, both species likely hailed from ancestors that came to Europe from Africa and adapted to living conditions in Ice Age Europe. The species also both became extinct more or less at the same time.

"It is now possible to try to answer a question no one has asked before: Are there genetic similarities between evolutionary adaptation paths in Neanderthals and mammoths?" Prof. Barkai says. "The answer seems to be yes. This idea alone opens endless avenues for new research in evolution, archaeology and other disciplines.

Read more at Science Daily

New state of matter: Elements can be solid and liquid at same time

Potassium.

Scientists have discovered a new state of physical matter in which atoms can exist as both solid and liquid simultaneously.

Until now, the atoms in physical material were understood to exist typically in one of three states -- solid, liquid or gas. Researchers have found, however, that some elements can, when subjected to extreme conditions, take on the properties of both solid and liquid states.

Applying high pressures and temperatures to potassium -- a simple metal -- creates a state in which most of the element's atoms form a solid lattice structure, the findings show. However, the structure also contains a second set of potassium atoms that are in a fluid arrangement.

Under the right conditions, over half a dozen elements -- including sodium and bismuth -- are thought to be capable of existing in the newly discovered state, researchers say.

Until now, it was unclear if the unusual structures represented a distinct state of matter, or existed as transition stages between two distinct states.

A team led by scientists from the University of Edinburgh used powerful computer simulations to study the existence of the state -- known as the chain-melted state. Simulating how up to 20,000 potassium atoms behave under extreme conditions revealed that the structures formed represent the new, stable state of matter.

Applying pressure to the atoms leads to the formation of two interlinked solid lattice structures, the team says. Chemical interactions between atoms in one lattice are strong, meaning they stay in a solid form when the structure is heated, while the other atoms melt into a liquid state.

The study, published in the journal Proceedings of the National Academy of Sciences, was supported by the European Research Council and the Engineering and Physical Sciences Research Council. The work was carried out in collaboration with scientists from Xi'an Jiantong University in China.

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Are brown dwarfs failed stars or super-planets?

Artist rendering of a brown dwarf. They are more massive and hotter than planets but lack the nuclear fusion in their core as in normal stars. Two such “failed” stars were detected orbiting the star ? Ophiuchi. They were probably formed in the earlier protoplanetary disk of the star.

Brown dwarfs fill the "gap" between stars and the much smaller planets -- two very different types of astronomical objects. But how they originate has yet to be fully explained. Astronomers from Heidelberg University may now be able to answer that question. They discovered that the star ν Ophiuchi in the Milky Way is being orbited by two brown dwarfs, which in all probability formed along with the star from a gas and dust disk, just as planets do. The research results were published in Astronomy & Astrophysics.

Brown dwarfs orbit either one star or travel in isolation in the vast expanse of the Milky Way. Their mass -- they are at least 13 times heavier than the planet Jupiter -- is sufficient to generate, at least temporarily, energy in their core through nuclear fusion. They are not sufficiently massive, however, to ignite hydrogen in their cores and hence to create their own light. The heat they continue to radiate after formation is how astronomers are able to locate them. It is estimated that up to 100 billion brown dwarfs make their home in the Milky Way. Yet it remains unclear how they form -- whether they are "failed" stars or possibly even super-planets.

The recent discoveries made at the Centre for Astronomy of Heidelberg University (ZAH) could provide an answer. Prof. Dr Andreas Quirrenbach and his team at the Königstuhl State Observatory of the ZAH analysed the variations in radial velocity of the star ν Ophiuchi. Using telescopes in the USA and Japan, the Heidelberg astronomers and others measured the velocity of the star for 11 years. The star has a mass slightly greater than two and half times that of the Sun, and is located approximately 150 light years from Earth in the constellation Ophiuchus.

The Heidelberg team noticed a certain pattern in the measurements, similar to those caused by orbiting planets or binary stars, which is usually nothing out of the ordinary. But in this case, in-depth analysis of the data revealed something extraordinary: apparently, ν Ophiuchi is being orbited by two brown dwarfs with an orbital period of approximately 530 and 3,185 days, which puts them in a 6:1 resonant configuration. So, the brown dwarf closest to ν Ophiuchi orbits its star exactly six times while the other, more distant brown dwarf completes only one orbit.

This discovery sheds completely new light on the evolution of brown dwarfs. Do they develop exclusively like normal stars in interstellar clouds, or can they also form in the so-called protoplanetary disk of gas and dust that surrounds the parent star in the early phase of its formation? "The 6:1 resonance is a strong indication for the latter scenario," explains Prof. Quirrenbach. "Only then could the orbits of the newly developing brown dwarfs adjust to a stable resonance over millions of years."

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Life could be evolving right now on nearest exoplanets

The intense radiation environments around nearby M stars could favor habitable worlds resembling younger versions of Earth.

Rocky, Earth-like planets orbiting our closest stars could host life, according to a new study that raises the excitement about exoplanets.

When rocky, Earth-like planets were discovered orbiting in the habitable zone of some of our closest stars, excitement skyrocketed -- until hopes for life were dashed by the high levels of radiation bombarding those worlds.

Proxima-b, only 4.24 light years away, receives 250 times more X-ray radiation than Earth and could experience deadly levels of ultraviolet radiation on its surface. How could life survive such a bombardment? Cornell University astronomers say that life already has survived this kind of fierce radiation, and they have proof: you.

Lisa Kaltenegger and Jack O'Malley-James make their case in a new paper, published in Monthly Notices of the Royal Astronomical Society. Kaltenegger is associate professor of astronomy and director of Cornell's Carl Sagan Institute, at which O'Malley-James is a research associate.

All of life on Earth today evolved from creatures that thrived during an even greater UV radiation assault than Proxima-b, and other nearby exoplanets, currently endure. The Earth of 4 billion years ago was a chaotic, irradiated, hot mess. Yet in spite of this, life somehow gained a toehold and then expanded.

The same thing could be happening at this very moment on some of the nearest exoplanets, according to Kaltenegger and O'Malley-James. The researchers modeled the surface UV environments of the four exoplanets closest to Earth that are potentially habitable: Proxima-b, TRAPPIST-1e, Ross-128b and LHS-1140b.

These planets orbit small red dwarf stars which, unlike our sun, flare frequently, bathing their planets in high-energy UV radiation. While it is unknown exactly what conditions prevail upon the surface of the planets orbiting these flaring stars, it is known that such flares are biologically damaging and can cause erosion in planetary atmospheres. High levels of radiation cause biological molecules like nucleic acids to mutate or even shut down.

O'Malley-James and Kaltenegger modeled various atmospheric compositions, from ones similar to present-day Earth to "eroded" and "anoxic" atmospheres -- those with very thin atmospheres that don't block UV radiation well and those without the protection of ozone, respectively. The models show that as atmospheres thin and ozone levels decrease, more high-energy UV radiation reaches the ground. The researchers compared the models to Earth's history, from nearly 4 billion years ago to today.

Although the modeled planets receive higher UV radiation than that emitted by our own sun today, this is significantly lower than what Earth received 3.9 billion years ago.

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Revolutionary camera allows scientists to predict evolution of ancient stars

For the first time scientists have been able to prove a decades old theory on stars thanks to a revolutionary high-speed camera.

Scientists at the University of Sheffield have been working with HiPERCAM, a high-speed, multicolour camera, which is capable of taking more than 1,000 images per second, allowing experts to measure both the mass and the radius of a cool subdwarf star for the first time.

The findings published today (8 April 2019) in Nature Astronomy have allowed researchers to verify the commonly used stellar structure model -- which describes the internal structure of a star in detail -- and make detailed predictions about the brightness, the colour and its future evolution.

Scientists know that old stars have fewer metals than young stars, but the effects of this on the structure of stars was, until now, untested. Old stars (often referred to as cool subdwarf stars) are faint and there are few in the solar neighbourhood.

Up until now scientists have not had a camera powerful enough to be able to get precise measurements of their stellar parameters such as the mass and the radius.

HiPERCAM can take one picture every millisecond as opposed to a normal camera on a large telescope which usually captures only one picture every few minutes. This has given scientists the ability to measure the star accurately for the first time.

Professor Vik Dhillon, Dr Steven Parsons and Dr Stuart Littlefair, from the Department of Physics and Astronomy at the University of Sheffield, led the HiPERCAM project in partnership with the Science and Technology Facilities Council's Astronomy Technology Centre (ATC) and the Instituto de Astrofisica de Canarias, along with researchers from the University of Warwick and Durham University.

Professor Dhillon said: "Now we have been able to measure the size of the star we can see it is in line with stellar structure theory. These results would not have been possible with any other telescope.

"This not only proves stellar structure theory, but has also verified the potential of HiPERCAM."

The paper is the first to be published using HiPERCAM data, which is mounted on the Gran Telescopio Canarias (GTC) -- the world's largest optical telescope, with a 10.4 metre mirror diameter.

The camera can take high-speed images of objects in the universe, allowing their rapid brightness variations -- due to phenomena such as eclipses and explosions -- to be studied in unprecedented detail.

Data captured by the camera, taken in five different colours simultaneously, allow scientists to study the remnants of dead stars such as white dwarfs, neutron stars and black holes.

The GTC is based on the island of La Palma, situated 2,500 metres above sea level, which is one of the best places in the world to study the night sky.

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