Planet found orbiting small, cool star

Using the supersharp radio "vision" of the National Science Foundation's continent-wide Very Long Baseline Array (VLBA), astronomers have discovered a Saturn-sized planet closely orbiting a small, cool star 35 light-years from Earth. This is the first discovery of an extrasolar planet with a radio telescope using a technique that requires extremely precise measurements of a star's position in the sky, and only the second planet discovery for that technique and for radio telescopes.

The technique has long been known, but has proven difficult to use. It involves tracking the star's actual motion in space, then detecting a minuscule "wobble" in that motion caused by the gravitational effect of the planet. The star and the planet orbit a location that represents the center of mass for both combined. The planet is revealed indirectly if that location, called the barycenter, is far enough from the star's center to cause a wobble detectable by a telescope.

This technique, called the astrometric technique, is expected to be particularly good for detecting Jupiter-like planets in orbits distant from the star. This is because when a massive planet orbits a star, the wobble produced in the star increases with a larger separation between the planet and the star, and at a given distance from the star, the more massive the planet, the larger the wobble produced.

Starting in June of 2018 and continuing for a year and a half, the astronomers tracked a star called TVLM 513-46546, a cool dwarf with less than a tenth the mass of our Sun. In addition, they used data from nine previous VLBA observations of the star between March 2010 and August 2011.

Extensive analysis of the data from those time periods revealed a telltale wobble in the star's motion indicating the presence of a planet comparable in mass to Saturn, orbiting the star once every 221 days. This planet is closer to the star than Mercury is to the Sun.

Small, cool stars like TVLM 513-46546 are the most numerous stellar type in our Milky Way Galaxy, and many of them have been found to have smaller planets, comparable to Earth and Mars.

"Giant planets, like Jupiter and Saturn, are expected to be rare around small stars like this one, and the astrometric technique is best at finding Jupiter-like planets in wide orbits, so we were surprised to find a lower mass, Saturn-like planet in a relatively compact orbit. We expected to find a more massive planet, similar to Jupiter, in a wider orbit," said Salvador Curiel, of the National Autonomous University of Mexico. "Detecting the orbital motions of this sub-Jupiter mass planetary companion in such a compact orbit was a great challenge," he added.

More than 4,200 planets have been discovered orbiting stars other than the Sun, but the planet around TVLM 513-46546 is only the second to be found using the astrometric technique. Another, very successful method, called the radial velocity technique, also relies on the gravitational effect of the planet upon the star. That technique detects the slight acceleration of the star, either toward or away from Earth, caused by the star's motion around the barycenter.

"Our method complements the radial velocity method which is more sensitive to planets orbiting in close orbits, while ours is more sensitive to massive planets in orbits further away from the star," said Gisela Ortiz-Leon of the Max Planck Institute for Radio Astronomy in Germany. "Indeed, these other techniques have found only a few planets with characteristics such as planet mass, orbital size, and host star mass, similar to the planet we found. We believe that the VLBA, and the astrometry technique in general, could reveal many more similar planets."

A third technique, called the transit method, also very successful, detects the slight dimming of the star's light when a planet passes in front of it, as seen from Earth.

The astrometric method has been successful for detecting nearby binary star systems, and was recognized as early as the 19th Century as a potential means of discovering extrasolar planets. Over the years, a number of such discoveries were announced, then failed to survive further scrutiny. The difficulty has been that the stellar wobble produced by a planet is so small when seen from Earth that it requires extraordinary precision in the positional measurements.

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Surprisingly dense exoplanet challenges planet formation theories

New detailed observations with NSF's NOIRLab facilities reveal a young exoplanet, orbiting a young star in the Hyades cluster, that is unusually dense for its size and age. Weighing in at 25 Earth-masses, and slightly smaller than Neptune, this exoplanet's existence is at odds with the predictions of leading planet formation theories.

New observations of the exoplanet, known as K2-25b, made with the WIYN 0.9-meter Telescope at Kitt Peak National Observatory (KPNO), a Program of NSF's NOIRLab, the Hobby-Eberly Telescope at McDonald Observatory and other facilities, raise new questions about current theories of planet formation. The exoplanet has been found to be unusually dense for its size and age -- raising the question of how it came to exist. Details of the findings appear in The Astronomical Journal.

Slightly smaller than Neptune, K2-25b orbits an M-dwarf star -- the most common type of star in the galaxy -- in 3.5 days. The planetary system is a member of the Hyades star cluster, a nearby cluster of young stars in the direction of the constellation Taurus. The system is approximately 600 million years old, and is located about 150 light-years from Earth.

Planets with sizes between those of Earth and Neptune are common companions to stars in the Milky Way, despite the fact that no such planets are found in our Solar System. Understanding how these "sub-Neptune" planets form and evolve is a frontier question in studies of exoplanets.

Astronomers predict that giant planets form by first assembling a modest rock-ice core of 5-10 times the mass of Earth and then enrobing themselves in a massive gaseous envelope hundreds of times the mass of Earth. The result is a gas giant like Jupiter. K2-25b breaks all the rules of this conventional picture: with a mass 25 times that of Earth and modest in size, K2-25b is nearly all core and very little gaseous envelope. These strange properties pose two puzzles for astronomers. First, how did K2-25b assemble such a large core, many times the 5-10 Earth-mass limit predicted by theory? And second, with its high core mass -- and consequent strong gravitational pull -- how did it avoid accumulating a significant gaseous envelope?

The team studying K2-25b found the result surprising. "K2-25b is unusual,"said Gudmundur Stefansson, a postdoctoral fellow at Princeton University, who led the research team. According to Stefansson, the exoplanet is smaller in size than Neptune but about 1.5 times more massive. "The planet is dense for its size and age, in contrast to other young, sub-Neptune-sized planets that orbit close to their host star," said Stefansson. "Usually these worlds are observed to have low densities -- and some even have extended evaporating atmospheres. K2-25b, with the measurements in hand, seems to have a dense core, either rocky or water-rich, with a thin envelope."

To explore the nature and origin of K2-25b, astronomers determined its mass and density. Although the exoplanet's size was initially measured with NASA's Kepler satellite, the size measurement was refined using high-precision measurements from the WIYN 0.9-meter Telescope at KPNO and the 3.5-meter telescope at Apache Point Observatory (APO) in New Mexico. The observations made with these two telescopes took advantage of a simple but effective technique that was developed as part of Stefansson's doctoral thesis. The technique uses a clever optical component called an Engineered Diffuser, which can be obtained off the shelf for around $500. It spreads out the light from the star to cover more pixels on the camera, allowing the brightness of the star during the planet's transit to be more accurately measured, and resulting in a higher-precision measurement of the size of the orbiting planet, among other parameters.

"The innovative diffuser allowed us to better define the shape of the transit and thereby further constrain the size, density and composition of the planet," said Jayadev Rajagopal, an astronomer at NOIRLab who was also involved in the study.

For its low cost, the diffuser delivers an outsized scientific return. "Smaller aperture telescopes, when equipped with state-of-the-art, but inexpensive, equipment can be platforms for high impact science programs," explains Rajagopal. "Very accurate photometry will be in demand for exploring host stars and planets in tandem with space missions and larger apertures from the ground, and this is an illustration of the role that a modest-sized 0.9-meter telescope can play in that effort."

Thanks to the observations with the diffusers available on the WIYN 0.9-meter and APO 3.5-meter telescopes, astronomers are now able to predict with greater precision when K2-25b will transit its host star. Whereas before transits could only be predicted with a timing precision of 30-40 minutes, they are now known with a precision of 20 seconds. The improvement is critical to planning follow-up observations with facilities such as the international Gemini Observatory and the James Webb Space Telescope.

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Key brain region was 'recycled' as humans developed the ability to read

Humans began to develop systems of reading and writing only within the past few thousand years. Our reading abilities set us apart from other animal species, but a few thousand years is much too short a timeframe for our brains to have evolved new areas specifically devoted to reading.

To account for the development of this skill, some scientists have hypothesized that parts of the brain that originally evolved for other purposes have been "recycled" for reading. As one example, they suggest that a part of the visual system that is specialized to perform object recognition has been repurposed for a key component of reading called orthographic processing -- the ability to recognize written letters and words.

A new study from MIT neuroscientists offers evidence for this hypothesis. The findings suggest that even in nonhuman primates, who do not know how to read, a part of the brain called the inferotemporal (IT) cortex is capable of performing tasks such as distinguishing words from nonsense words, or picking out specific letters from a word.

"This work has opened up a potential linkage between our rapidly developing understanding of the neural mechanisms of visual processing and an important primate behavior -- human reading," says James DiCarlo, the head of MIT's Department of Brain and Cognitive Sciences, an investigator in the McGovern Institute for Brain Research and the Center for Brains, Minds, and Machines, and the senior author of the study.

Rishi Rajalingham, an MIT postdoc,, is the lead author of the study, which appears today in Nature Communications. Other MIT authors are postdoc Kohitij Kar and technical associate Sachi Sanghavi. The research team also includes Stanislas Dehaene, a professor of experimental cognitive psychology at the Collège de France.

Word recognition

Reading is a complex process that requires recognizing words, assigning meaning to those words, and associating words with their corresponding sound. These functions are believed to be spread out over different parts of the human brain.

Functional magnetic resonance imaging (fMRI) studies have identified a region called the visual word form area (VWFA) that lights up when the brain processes a written word. This region is involved in the orthographic stage: It discriminates words from jumbled strings of letters or words from unknown alphabets. The VWFA is located in the IT cortex, a part of the visual cortex that is also responsible for identifying objects.

DiCarlo and Dehaene became interested in studying the neural mechanisms behind word recognition after cognitive psychologists in France reported that baboons could learn to discriminate words from nonwords, in a study that appeared in Science in 2012.

Using fMRI, Dehaene's lab has previously found that parts of the IT cortex that respond to objects and faces become highly specialized for recognizing written words once people learn to read.

"However, given the limitations of human imaging methods, it has been challenging to characterize these representations at the resolution of individual neurons, and to quantitatively test if and how these representations might be reused to support orthographic processing," Dehaene says. "These findings inspired us to ask if nonhuman primates could provide a unique opportunity to investigate the neuronal mechanisms underlying orthographic processing."

The researchers hypothesized that if parts of the primate brain are predisposed to process text, they might be able to find patterns reflecting that in the neural activity of nonhuman primates as they simply look at words.

To test that idea, the researchers recorded neural activity from about 500 neural sites across the IT cortex of macaques as they looked at about 2,000 strings of letters, some of which were English words and some of which were nonsensical strings of letters.

"The efficiency of this methodology is that you don't need to train animals to do anything," Rajalingham says. "What you do is just record these patterns of neural activity as you flash an image in front of the animal."

The researchers then fed that neural data into a simple computer model called a linear classifier. This model learns to combine the inputs from each of the 500 neural sites to predict whether the string of letters that provoked that activity pattern was a word or not. While the animal itself is not performing this task, the model acts as a "stand-in" that uses the neural data to generate a behavior, Rajalingham says.

Using that neural data, the model was able to generate accurate predictions for many orthographic tasks, including distinguishing words from nonwords and determining if a particular letter is present in a string of words. The model was about 70 percent accurate at distinguishing words from nonwords, which is very similar to the rate reported in the 2012 Science study with baboons. Furthermore, the patterns of errors made by model were similar to those made by the animals.

Neuronal recycling

The researchers also recorded neural activity from a different brain area that also feeds into IT cortex: V4, which is part of the visual cortex. When they fed V4 activity patterns into the linear classifier model, the model poorly predicted (compared to IT) the human or baboon performance on the orthographic processing tasks.

The findings suggest that the IT cortex is particularly well-suited to be repurposed for skills that are needed for reading, and they support the hypothesis that some of the mechanisms of reading are built upon highly evolved mechanisms for object recognition, the researchers say.

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Ancient part of immune system may underpin severe COVID

One of the immune system's oldest branches, called complement, may be influencing the severity of COVID disease, according to a new study from researchers at Columbia University Irving Medical Center.

Among other findings linking complement to COVID, the researchers found that people with age-related macular degeneration -- a disorder caused by overactive complement -- are at greater risk of developing severe complications and dying from COVID.

The connection with complement suggests that existing drugs that inhibit the complement system could help treat patients with severe disease.

The study was published on Aug. 3 in Nature Medicine.

The authors also found evidence that clotting activity is linked to COVID severity and that mutations in certain complement and coagulation genes are associated with hospitalization of COVID patients.

"Together these results provide important insights into the pathophysiology of COVID-19 and paint a picture for the role of complement and coagulation pathways in determining clinical outcomes of patients infected with SARS-CoV-2," says Sagi Shapira, PhD, MPH, who led the study with Nicholas Tatonetti, PhD, both professors at Columbia University Vagelos College of Physicians and Surgeons.

Findings Stem from Study of Coronavirus Mimicry

The idea to investigate the role of coagulation and complement in COVID began with a sweeping survey of viral mimicry across all viruses on earth -- over 7,000 in all.

"Viruses have proteins that can mimic certain host proteins to trick the host's cells into aiding the virus with completing its life cycle," Shapira says. "Beyond the fundamental biological questions that we were interested in addressing, based on our previous work and the work of others, we suspected that identifying those mimics could provide clues about how viruses cause disease."

Coronaviruses, the survey found, are masters of mimicry, particularly with proteins involved in coagulation and proteins that make up complement, one of the oldest branches of the human immune system.

Complement proteins work a bit like antibodies and help eliminate pathogens by sticking to viruses and bacteria and marking them for destruction. Complement can also increase coagulation and inflammation in the body. "Unchecked, these systems can also be quite detrimental," says Shapira.

"The new coronavirus -- by mimicking complement or coagulation proteins -- might drive both systems into a hyperactive state."

Macular Degeneration Associated with Greater COVID Mortality

If complement and coagulation influence severity of COVID, people with pre-existing hyperactive complement or coagulation disorders should be more susceptible to the virus.

That led Shapira and Tatonetti to look at COVID patients with macular degeneration, an eye disease caused by overactive complement, as well as common coagulation disorders like thrombosis and hemorrhage.

Among 11,000 COVID patients who came to Columbia University Irving Medical Center with suspected COVID-19, the researchers found that over 25% of those with age-related macular degeneration died, compared to the average mortality rate of 8.5%, and roughly 20% required intubation. The greater mortality and intubation rates could not be explained by differences in the age or sex of the patients.

"Complement is also more active in obesity and diabetes," Shapira says, "and may help explain, at least in part, why people with those conditions also have a greater mortality risk from COVID."

People with a history of coagulation disorders also were at increased risk of dying from COVID infection.

Coagulation and Complement Pathways Activated

The researchers then examined how gene activity differed in people infected with the coronavirus.

That analysis revealed a signature in COVID-infected patients indicating that the virus engages and induces robust activation of the body's complement and coagulation systems.

"We found that complement is one of the most differentially expressed pathways in SARS-CoV-2 infected patients," Tatonetti says. "As part of the immune system, you would expect to see complement activated, but it seems over and above what you'd see in other infections like the flu."

Some Coagulation and Complement Genes are Associated with Hospitalization

More evidence linking severe COVID with coagulation and complement comes from a genetic analysis of thousands of COVID patients from the U.K. Biobank, which contains medical records and genetic data on half a million people.

The authors found that variants of several genes that influence complement or coagulation activity are associated with more severe COVID symptoms that required hospitalization.

"These variants are not necessarily going to determine someone's outcome," Shapira says. "But this finding is another line of evidence that complement and coagulation pathways participate in the morbidity and mortality associated with COVID-19."

Targeting Coagulation and Complement

Physicians treating COVID patients have noticed coagulation issues since the beginning of the pandemic, and several clinical trials are underway to determine the best way to use existing anti-coagulation treatments.

Complement inhibitors are currently used in relatively rare diseases, but at least one clinical trial is testing the idea with COVID patients.

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NASA astronauts safely splash down after first commercial crew flight to space station

A SpaceX fast boat races toward the SpaceX Crew Dragon spacecraft moments before it splashed down in the Gulf of Mexico with NASA astronauts Bob Behnken and Doug Hurley aboard.

Two NASA astronauts splashed down safely in the Gulf of Mexico Sunday for the first time in a commercially built and operated American crew spacecraft, returning from the International Space Station to complete a test flight that marks a new era in human spaceflight.

SpaceX's Crew Dragon, carrying Robert Behnken and Douglas Hurley, splashed down under parachutes in the Gulf of Mexico off the coast of Pensacola, Florida at 2:48 p.m. EDT Sunday and was successfully recovered by SpaceX. After returning to shore, the astronauts immediately will fly back to Houston.

"Welcome home, Bob and Doug! Congratulations to the NASA and SpaceX teams for the incredible work to make this test flight possible," said NASA Administrator Jim Bridenstine. "It's a testament to what we can accomplish when we work together to do something once thought impossible. Partners are key to how we go farther than ever before and take the next steps on daring missions to the Moon and Mars."

Behnken and Hurley's return was the first splashdown for American astronauts since Thomas Stafford, Vance Brand, and Donald "Deke" Slayton landed in the Pacific Ocean off the coast of Hawaii on July 24, 1975, at the end of the Apollo-Soyuz Test Project.

NASA's SpaceX Demo-2 test flight launched May 30 from the Kennedy Space Center in Florida. After reaching orbit, Behnken and Hurley named their Crew Dragon spacecraft "Endeavour" as a tribute to the first space shuttle each astronaut had flown aboard.

Nearly 19 hours later, Crew Dragon docked to the forward port of the International Space Station's Harmony module May 31.

"On behalf of all SpaceX employees, thank you to NASA for the opportunity to return human spaceflight to the United States by flying NASA astronauts Bob Behnken and Doug Hurley," said SpaceX President and Chief Operating Officer Gwynne Shotwell. "Congratulations to the entire SpaceX and NASA team on such an extraordinary mission. We could not be more proud to see Bob and Doug safely back home -- we all appreciate their dedication to this mission and helping us start the journey towards carrying people regularly to low Earth orbit and on to the Moon and Mars. And I really hope they enjoyed the ride!"

Behnken and Hurley participated in a number of scientific experiments, spacewalks and public engagement events during their 62 days aboard station. Overall, the astronaut duo spent 64 days in orbit, completed 1,024 orbits around Earth and traveled 27,147,284 statute miles.

The astronauts contributed more than 100 hours of time to supporting the orbiting laboratory's investigations. Hurley conducted the Droplet Formation Study inside of the Microgravity Science Glovebox (MSG), which evaluates water droplet formation and water flow. Hurley also conducted the Capillary Structures investigation, which studies the use of different structures and containers to manage fluids and gases.

Hurley and Behnken worked on numerous sample switch outs for the Electrolysis Measurement (EM) experiment, which looks at bubbles created using electrolysis and has implications for numerous electrochemical reactions and devices. Both crew members also contributed images to the Crew Earth Observations (CEO) study. CEO images help record how our planet is changing over time, from human-caused changes -- such as urban growth and reservoir construction -- to natural dynamic events, including hurricanes, floods, and volcanic eruptions.

Behnken conducted four spacewalks while on board the space station with Expedition 63 Commander and NASA colleague Chris Cassidy. The duo upgraded two power channels on the far starboard side of the station's truss with new lithium-ion batteries. They also routed power and Ethernet cables, removed H-fixtures that were used for ground processing of the solar arrays prior to their launch, installed a protective storage unit for robotic operations, and removed shields and coverings in preparation for the arrival later this year of the Nanoracks commercial airlock on a SpaceX cargo delivery mission.

Behnken now is tied for most spacewalks by an American astronaut with Michael Lopez-Alegria, Peggy Whitson, and Chris Cassidy, each of whom has completed 10 spacewalks. Behnken now has spent a total of 61 hours and 10 minutes spacewalking, which makes him the U.S. astronaut with the third most total time spacewalking, behind Lopez-Alegria and Andrew Feustel, and the fourth most overall.

The Demo-2 test flight is part of NASA's Commercial Crew Program, which has worked with the U.S. aerospace industry to launch astronauts on American rockets and spacecraft from American soil to the space station for the first time since 2011. This is SpaceX's final test flight and is providing data on the performance of the Falcon 9 rocket, Crew Dragon spacecraft and ground systems, as well as in-orbit, docking, splashdown, and recovery operations.

Crew Dragon Endeavour will return back to SpaceX's Dragon Lair in Florida for inspection and processing. Teams will examine the spacecraft's data and performance from throughout the test flight. The completion of Demo-2 and the review of the mission and spacecraft pave the way for NASA to certify SpaceX's crew transportation system for regular flights carrying astronauts to and from the space station. SpaceX is readying the hardware for the first rotational mission, called Crew-1, later this year. This mission would occur after NASA certification, which is expected to take about six weeks.

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Study sheds light on the evolution of the earliest dinosaurs

Illustration of prehistoric dinosaur scene

The classic dinosaur family tree has two subdivisions of early dinosaurs at its base: the Ornithischians, or bird-hipped dinosaurs, which include the later Triceratops and Stegosaurus; and the Saurischians, or lizard-hipped dinosaurs, such as Brontosaurus and Tyrannosaurus.

In 2017, however, this classical view of dinosaur evolution was thrown into question with evidence that perhaps the lizard-hipped dinosaurs evolved first -- a finding that dramatically rearranged the first major branches of the dinosaur family tree.

Now an MIT geochronologist, along with paleontologists from Argentina and Brazil, has found evidence to support the classical view of dinosaur evolution. The team's findings are published today in the journal Scientific Reports.

The team reanalyzed fossils of Pisanosaurus, a small bipedal dinosaur that is thought to be the earliest preserved Ornithiscian in the fossil record. The researchers determined that the bird-hipped herbivore dates back to 229 million years ago, which is also around the time that the earliest lizard-hipped Saurischians are thought to have appeared.

The new timing suggests that Ornithiscians and Saurischians first appeared and diverged from a common ancestor at roughly the same time, giving support to the classical view of dinosaur evolution.

The researchers also dated rocks from the Ischigualasto Formation, a layered sedimentary rock unit in Argentina that is known for having preserved an abundance of fossils of the very earliest dinosaurs. Based on these fossils and others across South America, scientists believe that dinosaurs first appeared in the southern continent, which at the time was fused together with the supercontinent of Pangaea. The early dinosaurs are then thought to have diverged and fanned out across the world.

However, in the new study, the researchers determined that the period over which the Ischigualasto Formation was deposited overlaps with the timing of another important geological deposit in North America, known as the Chinle Formation.

The middle layers of the Chinle Formation in the southwestern U.S. contain fossils of various fauna, including dinosaurs that appear to be more evolved than the earliest dinosaurs. The bottom layers of this formation, however, lack animal fossil evidence of any kind, let alone early dinosaurs. This suggests that conditions within this geological window prevented the preservation of any form of life, including early dinosaurs, if they walked this particular region of the world.

"If the Chinle and Ischigualasto formations overlap in time, then early dinosaurs may not have first evolved in South America, but may have also been roaming North America around the same time," says Jahandar Ramezani, a research scientist in MIT's Department of Earth, Atmospheric, and Planetary Sciences, who co-authored the study. "Those northern cousins just may not have been preserved."

The other researchers on the study are first author Julia Desojo from the National University of La Plata Museum, and a team of paleontologists from institutions across Argentina and Brazil.

"Following footsteps"

The earliest dinosaur fossils found in the Ischigualasto Formation are concentrated within what is now a protected provincial park known as "Valley of the Moon" in the San Juan Province. The geological formation also extends beyond the park, albeit with fewer fossils of early dinosaurs. Ramezani and his colleagues instead looked to study one of the accessible outcrops of the same rocks, outside of the park.

They focused on Hoyada del Cerro Las Lajas, a less-studied outcrop of the Ischigualasto Formation, in La Rioja Province, which another team of paleontologists explored in the 1960s.

"Our group got our hands on some of the field notes and excavated fossils from those early paleontologists, and thought we should follow their footsteps to see what we could learn," Desojo says.

Over four expeditions between 2013 to 2019, the team collected fossils and rocks from various layers of the Las Lajas outcrop, including more than 100 new fossil specimens, though none of these fossils were of dinosaurs. Nevertheless, they analyzed the fossils and found they were comparable, in both species and relative age, to nondinosaur fossils found in the park region of the same Ischigualasto Formation. They also found out that the Ischigualasto Formation in Las Lajas was significantly thicker and much more complete than the outcrops in the park. This gave them confidence that the geological layers in both locations were deposited during the same critical time interval.

Ramezani then analyzed samples of volcanic ash collected from several layers of the Las Lajas outcrops. Volcanic ash contains zircon, a mineral that he separated from the rest of the sediment, and measured for isotopes of uranium and lead, the ratios of which yield the mineral's age.

With this high-precision technique, Ramezani dated samples from the top and bottom of the outcrop, and found that the sedimentary layers, and any fossils preserved within them, were deposited between 230 million and 221 million years ago. Since the team determined that the layered rocks in Las Lajas and the park match in both species and relative timing, they could also now determine the exact age of the park's more fossil-rich outcrops.

Moreover, this window overlaps significantly with the time interval over which sediments were deposited, thousands of kilometers northward, in the Chinle Formation.

"For many years, people thought Chinle and Ischigualasto formations didn't overlap, and based on that assumption, they developed a model of diachronous evolution, meaning the earliest dinosaurs appeared in South America first, then spread out to other parts of the world including North America," Ramezani says. "We've now studied both formations extensively, and shown that diachronous evolution isn't really based on sound geology."

A family tree, preserved

Decades before Ramezani and his colleagues set out for Las Lajas, other paleontologists had explored the region and unearthed numerous fossils, including remains of Pisanosaurus mertii, a small, light-framed, ground-dwelling herbivore. The fossils are now preserved in an Argentinian museum, and scientists have gone back and forth on whether it is a true dinosaur belonging to the Ornithiscian group, or a " basal dinosauromorph" -- a kind of pre-dinosaur, with features that are almost, but not quite fully, dinosaurian.

"The dinosaurs we see in the Jurassic and Cretaceous are highly evolved, and ones we can nicely identify, but in the late Triassic, they all looked very much alike, so it's very hard to distinguish them from each other, and from basal dinosauromorphs," Ramezani explains.

His collaborator Max Langer from the University of São Paulo in Brazil painstakingly reanalyzed the museum-preserved fossil of Pisanosaurus, and concluded, based on certain key anatomical features, that it is indeed a dinosaur -- and what's more, that it is the earliest preserved Ornithiscian specimen. Based on Ramezani's dating of the outcrop and the interpretation of Pisanosaurus, the researchers concluded that the earliest bird-hipped dinosaurs appeared around 229 million years ago -- around the same time as their lizard-hipped counterparts.

"We can now say the earliest Ornithiscians first showed up in the fossil record roughly around the same time as the Saurischians, so we shouldn't throw away the conventional family tree," Ramezani says. "There are all these debates about where dinosaurs appeared, how they diversified, what the family tree looked like. A lot of those questions are tied to geochronology, so we need really good, robust age constraints to help answer these questions."

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Early Mars was covered in ice sheets, not flowing rivers, researchers say

Illustration of Mars, polar ice cap

A large number of the valley networks scarring Mars's surface were carved by water melting beneath glacial ice, not by free-flowing rivers as previously thought, according to new UBC research published today in Nature Geoscience. The findings effectively throw cold water on the dominant "warm and wet ancient Mars" hypothesis, which postulates that rivers, rainfall and oceans once existed on the red planet.

To reach this conclusion, lead author Anna Grau Galofre, former PhD student in the department of earth, ocean and atmospheric sciences, developed and used new techniques to examine thousands of Martian valleys. She and her co-authors also compared the Martian valleys to the subglacial channels in the Canadian Arctic Archipelago and uncovered striking similarities.

"For the last 40 years, since Mars's valleys were first discovered, the assumption was that rivers once flowed on Mars, eroding and originating all of these valleys," says Grau Galofre. "But there are hundreds of valleys on Mars, and they look very different from each other. If you look at Earth from a satellite you see a lot of valleys: some of them made by rivers, some made by glaciers, some made by other processes, and each type has a distinctive shape. Mars is similar, in that valleys look very different from each other, suggesting that many processes were at play to carve them."

The similarity between many Martian valleys and the subglacial channels on Devon Island in the Canadian Arctic motivated the authors to conduct their comparative study. "Devon Island is one of the best analogues we have for Mars here on Earth -- it is a cold, dry, polar desert, and the glaciation is largely cold-based," says co-author Gordon Osinski, professor in Western University's department of earth sciences and Institute for Earth and Space Exploration.

In total, the researchers analyzed more than 10,000 Martian valleys, using a novel algorithm to infer their underlying erosion processes. "These results are the first evidence for extensive subglacial erosion driven by channelized meltwater drainage beneath an ancient ice sheet on Mars," says co-author Mark Jellinek, professor in UBC's department of earth, ocean and atmospheric sciences. "The findings demonstrate that only a fraction of valley networks match patterns typical of surface water erosion, which is in marked contrast to the conventional view. Using the geomorphology of Mars' surface to rigorously reconstruct the character and evolution of the planet in a statistically meaningful way is, frankly, revolutionary."

Grau Galofre's theory also helps explain how the valleys would have formed 3.8 billion years ago on a planet that is further away from the sun than Earth, during a time when the sun was less intense. "Climate modelling predicts that Mars' ancient climate was much cooler during the time of valley network formation," says Grau Galofre, currently a SESE Exploration Post-doctoral Fellow at Arizona State University. "We tried to put everything together and bring up a hypothesis that hadn't really been considered: that channels and valleys networks can form under ice sheets, as part of the drainage system that forms naturally under an ice sheet when there's water accumulated at the base."

These environments would also support better survival conditions for possible ancient life on Mars. A sheet of ice would lend more protection and stability of underlying water, as well as providing shelter from solar radiation in the absence of a magnetic field -- something Mars once had, but which disappeared billions of years ago.

While Grau Galofre's research was focused on Mars, the analytical tools she developed for this work can be applied to uncover more about the early history of our own planet. Jellinek says he intends to use these new algorithms to analyze and explore erosion features left over from very early Earth history.

Read more at Science Daily

Cooling of Earth caused by eruptions, not meteors

Volcanic eruption

Ancient sediment found in a central Texas cave appears to solve the mystery of why the Earth cooled suddenly about 13,000 years ago, according to a research study co-authored by a Texas A&M University professor.

Michael Waters, director of The Center for The Study of the First Americans and Distinguished Professor at Texas A&M University, and colleagues from Baylor University and the University of Houston have had their work published in Science Advances.

Some researchers believed the event -- which cooled the Earth by about 3 degrees Centigrade, a huge amount -- was caused by an extraterrestrial impact with the Earth, such as a meteor collision.

But Waters and the team found that the evidence left in layers of sediment in Hall's Cave were almost certainly the result of volcanic eruptions.

Waters said that Hall's Cave, located in the Texas hill country, has a sediment record extending over 20,000 years and he first began researching the cave in 2017.

"It is an exceptional record that offers a unique opportunity for interdisciplinary cooperation to investigate a number of important research questions," he said.

"One big question was, did an extraterrestrial impact occur near the end of the last ice age, about 13,000 years ago as the ice sheets covering Canada were melting, and cause an abrupt cooling that thrust the northern hemisphere back into the ice age for an extra 1,200 years?"

Waters and the team found that within the cave are layers of sediment, first identified by Thomas Stafford (Stafford Research Laboratories, Colorado), that dated to the time of the proposed impact that could answer the question and perhaps even identify the trigger that started the ancient cold snap.

The event also likely helped cause the extinction of large mammals such as mammoth, horse and camel that once roamed North America.

"This work shows that the geochemical signature associated with the cooling event is not unique but occurred four times between 9,000 and 15,000 years ago," said Alan Brandon, professor of geosciences at University of Houston and head of the research team.

"Thus, the trigger for this cooling event didn't come from space. Prior geochemical evidence for a large meteor exploding in the atmosphere instead reflects a period of major volcanic eruptions.

"I was skeptical," Brandon said. "We took every avenue we could to come up with an alternative explanation, or even avoid, this conclusion. A volcanic eruption had been considered one possible explanation but was generally dismissed because there was no associated geochemical fingerprint."

After a volcano erupts, the global spread of aerosols reflects incoming solar radiation away from Earth and may lead to global cooling post eruption for one to five years, depending on the size and timescales of the eruption, the team said.

"The Younger Dryas, which occurred about 13,000 years ago, disrupted distinct warming at the end of the last ice age," said co-author Steven Forman, professor of geosciences at Baylor.

The Earth's climate may have been at a tipping point at the end of Younger Dryas, possibly from the ice sheet discharge into the North Atlantic Ocean, enhanced snow cover and powerful volcanic eruptions that may have in combination led to intense Northern Hemisphere cooling, Forman said.

"This period of rapid cooling coincides with the extinction of a number of species, including camels and horses, and the appearance of the Clovis archaeological tradition," said Waters.

Brandon and fellow University of Houston scientist Nan Sun completed the isotopic analysis of sediments collected from Hall's Cave. They found that elements such as iridium, ruthenium, platinum, palladium and rhenium were not present in the correct proportions, meaning that a meteor or asteroid could not have caused the event.

"The isotope analysis and the relative proportion of the elements matched those that were found in previous volcanic gases," said Sun, lead author of the report.

Volcanic eruptions cause their most severe cooling near the source, usually in the year of the eruption, with substantially less cooling in the years after the eruption, the team said.

The Younger Dryas cooling lasted about 1,200 years, "so a sole volcanic eruptive cause is an important initiating factor, but other Earth system changes, such as cooling of the oceans and more snow cover were needed to sustain this colder period, "Forman said.

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Music training may not make children smarter after all

Music training does not have a positive impact on children's cognitive skills, such as memory, and academic achievement, such as maths, reading or writing, according to a study published in Memory & Cognition.

Previous research trials, carried out to examine a potential causal link between music training and improved cognitive and academic performance, have reached inconsistent conclusions, with some suggesting that there may be a link between music training and better cognitive and academic performance and others finding little effect.

Researchers Giovanni Sala at Fujita Health University, Japan and Fernand Gobet at the London School of Economics and Political Science, UK examined existing experimental evidence regarding the impact of music training on children's non-music cognitive skills and academic achievement.

The authors re-analyzed data from 54 previous studies conducted between 1986 and 2019, including a total of 6,984 children. They found that music training appeared to be ineffective at enhancing cognitive or academic skills, regardless of the type of skill (such as verbal, non-verbal, speed-related and so on), participants' age, and duration of music training.

When comparing between the individual studies included in their meta-analysis, the authors found that studies with high-quality study design, such as those which used a group of active controls -- children who did not learn music, but instead learned a different skill, such as dance or sports -- showed no effect of music education on cognitive or academic performance. Small effects were found in studies that did not include controls or which did not randomize participants into control groups (ones that received different or no training) and intervention groups (ones that received music training).

Giovanni Sala, the lead author said: "Our study shows that the common idea that 'music makes children smarter' is incorrect. On the practical side, this means that teaching music with the sole intent of enhancing a child's cognitive or academic skills may be pointless. While the brain can be trained in such a way that if you play music, you get better at music, these benefits do not generalize in such a way that if you learn music, you also get better at maths. Researchers' optimism about the benefits of music training appears to be unjustified and may stem from misinterpretation of previous empirical data."

Fernand Gobet, the corresponding author added: "Music training may nonetheless be beneficial for children, for example by improving social skills or self-esteem. Certain elements of music instruction, such as arithmetical music notation could be used to facilitate learning in other disciplines."

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'Little brain' or cerebellum not so little after all

When we say someone has a quick mind, it may be in part thanks to our expanded cerebellum that distinguishes human brains from those of macaque monkeys, for example.

Sometimes referred to by its Latin translation as the '"little brain"', the cerebellum is located close to the brainstem and sits under the cortex in the hindbrain. New research at San Diego State University, however, calls the "little" terminology into question.

The cerebellum plays a versatile role, contributing to our five senses as well as pain, movements, thought, and emotion.

It's essentially a flat sheet with the thickness of a crepe, crinkled into hundreds of folds to make it fit into a compact volume about one-eighth the volume of the cerebral cortex. For this reason, the surface area of the cerebellum was thought to be considerably smaller than that of the cerebral cortex.

By using an ultra-high-field 9.4 Tesla MRI machine to scan the brain and custom software to process the resulting images, an SDSU neuroimaging expert discovered the tightly packed folds actually contain a surface area equal to 80% of the cerebral cortex's surface area. In comparison, the macaque's cerebellum is about 30% the size of its cortex.

"The fact that it has such a large surface area speaks to the evolution of distinctively human behaviors and cognition," said Martin Sereno, psychology professor, cognitive neuroscientist and director of the SDSU MRI Imaging Center. "It has expanded so much that the folding patterns are very complex."

Unprecedented insights

Collaborating with imaging and cerebellum experts from the United Kingdom, Netherlands and Canada, Sereno used customized open source FreeSurfer software that he originally developed with colleagues while at the University of California San Diego to computationally reconstruct the folded surface of the cerebellum. The software also unfolds and flattens the cerebellar cortex so as to visualize it to the level of each individual folia -- or thin leaf like fold.

A pioneer in brain imaging who has leveraged functional MRI to uncover visual maps in the brain, Sereno found that when the cerebellum is completely unfolded, it forms a strange "crepe" four inches wide by three feet long. The findings were published this week in a study in PNAS (Proceedings of the National Academy of Sciences).

"Until now we only had crude models of what it looked like," Sereno said. "We now have a complete map or surface representation of the cerebellum, much like cities, counties, and states."

Puzzle pieces

Previous research discovered that while there were many similarities between the cortex and the cerebellum, there was one key difference. In the cerebral cortex, regions representing different parts of the body are arranged roughly like they are in the actual body: juxtaposed and orderly. But in the cerebellum, they were placed more randomly.

"You get a little chunk of the lip, next to a chunk of the shoulder or face, like jumbled puzzle pieces," Sereno explained.

Those parts of the cerebellum are therefore set up to pull in and coordinate information from disparate parts of the body.

It is intriguing to think that there might be analogs of '"fractured somatotopy"' in the cognitive parts of the cerebellum that could help support highly complex, sophisticated cognitive functions, such as language or abstract reasoning, Sereno said.

"When you think of the cognition required to write a scientific paper or explain a concept, you have to pull in information from many different sources. And that's just how the cerebellum is set up."

Until now, the cerebellum was thought to be involved mainly in basic functions like movement, but its expansion over time and its new inputs from cortical areas involved in cognition suggest that it can also process advanced concepts like mathematical equations.

"Now that we have the first high resolution base map of the human cerebellum, there are many possibilities for researchers to start filling in what is certain to be a complex quilt of inputs, from many different parts of the cerebral cortex in more detail than ever before," Sereno said.

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