Heavens

NASA's Hubble Space Telescope has given astronomers a peek at the location of the most energetic outburst ever seen in the universe -- a blast of gamma-rays a trillion times more powerful than visible light. That's because in a few seconds the gamma-ray burst (GRB) emitted more energy than the Sun will provide over its entire 10-billion year life.

In January 2019, an extremely bright and long-duration GRB was detected by a suite of telescopes, including NASA's Swift and Fermi telescopes, as well as by the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescopes on the Canary islands. Follow-up observations were made with Hubble to study the environment around the GRB and find out how this extreme emission is produced.

"Hubble's observations suggest that this particular burst was sitting in a very dense environment, right in the middle of a bright galaxy 5 billion light years away. This is really unusual, and suggests that this concentrated location might be why it produced this exceptionally powerful light," explained one of the lead authors, Andrew Levan of the Institute for Mathematics, Astrophysics and Particle Physics Department of Astrophysics at Radboud University in the Netherlands.

"Scientists have been trying to observe very high energy emission from gamma-ray bursts for a long time," explained lead author Antonio de Ugarte Postigo of the Instituto de Astrofísica de Andalucía in Spain. "This new Hubble observation of accompanying lower-energy radiation from the region is a vital step in our understanding of gamma-ray bursts [and] their immediate surroundings."

The complementary Hubble observations reveal that the GRB occurred within the central region of a massive galaxy. Researchers say that this is a denser environment than typically observed (for GRBs) and could have been crucial for the generation of the very-high-energy radiation that was observed. The host galaxy of the GRB is actually one of a pair of colliding galaxies. The galaxy interactions may have contributed to spawning the outburst.

Known as GRB 190114C, some of the radiation detected from the object had the highest energy ever observed. Scientists have been trying to observe such very high energy emission from GRBs for a long time, so this detection is considered a milestone in high-energy astrophysics, say researchers.

Previous observations revealed that to achieve this energy, material must be emitted from a collapsing star at 99.999% the speed of light. This material is then forced through the gas that surrounds the star, causing a shock that creates the gamma-ray burst itself.

Researchers at Tohoku University have, for the first time, successfully demonstrated a formation and current-induced motion of synthetic antiferromagnetic magnetic skyrmions. The established findings are expected to pave the way towards new functional information processing and storage technologies.

Magnetic skyrmion is known to be a topological object, emerged in magnetic systems. It possesses the ability to be made at nanoscale and to be driven by a current, showing promise for various applications where information is represented by the presence, absence, number, or state of the skyrmion. However, there remains one stumbling block - the skyrmion Hall effect.

The skyrmion Hall effect entails the skyrmion not moving along the current, but in the direction diagonal to the current because of the inherent angular momentum of the skyrmion, degrading the efficiency and stability of devices. As such, demand is high for technology that overcomes the skyrmion Hall effect.

The research group - which includes Professor Hideo Ohno (current Tohoku University President), Associate Professor Shunsuke Fukami, and Ph.D. candidate Mr. Takaaki Dohi - developed a magnetic stack structure in which the skyrmion is moved along the current, avoiding the skyrmion Hall effect.

The developed structure effectively exploits three spintronics effects, Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction, Dzyaloshinskii-Moriya (DM) interaction, and spin-orbit (SO) interaction. Due to the RKKY and DM interactions, a synthetic antiferromagnetically-coupled (SyAF) skyrmion is successfully formed. In addition, thanks to the SO interaction, the SyAF skyrmion is moved with a much smaller current than conventional single ferromagnetic skyrmion. Moreover, suppression of skyrmion Hall effect is confirmed for the SyAF system.

This is the first demonstration of the formation and current-induced motion of magnetic skyrmion circumventing the skyrmion Hall effect at room temperature. Ultimately, the present finding is expected to open the pathway to newer spintronics devices in which topology arising in magnetic materials is fully utilized.

MADISON - University of Wisconsin-Madison researchers have cultivated lifelike chemical reactions while pioneering a new strategy for studying the origin of life.

The work is far from jumpstarting life in the lab. Yet, it shows that simple laboratory techniques can spur the kinds of reactions that are likely necessary to explain how life got started on Earth some four billion years ago.

The researchers subjected a rich soup of organic chemicals to repeated selection by constantly paring down the chemical population and letting it build back up again with the addition of new resources. Over generations of selection, the system appeared to consume its raw materials, evidence that selection may have induced the spread of chemical networks capable of propagating themselves.

On longer timescales, these chemical changes oscillated in a repeating pattern. This boom-and-bust cycle isn't yet fully explained, but it is good evidence that the chemical soups established feedback loops resembling those found in living organisms.
David Baum, a UW-Madison professor of botany, and his team published their findings Oct. 23, 2019, in the journal Life. The work was funded by the National Science Foundation and NASA.

Now, other researchers can use this experimental approach and help untangle what components are necessary to encourage lifelike chemical systems and whether those chemical networks can go on to evolve more complex traits.

If this system can generate greater complexity, it might help solve the puzzle of how simple chemicals eventually gave rise to something as intricate as the cellular ancestor that spawned all life today.

"A core question in the origin of life is: How do you get evolution before there was genetic information like that within DNA or RNA?" says Baum. "What we've now realized is that the evolution of chemical networks may solve that problem, and that's something we can tackle in the lab."

To test the idea of chemical ecosystem evolution, the researchers assembled a rich soup of chemicals. In seawater, they dissolved amino acids, sugars, common organic compounds, trace minerals and the building blocks of nucleic acids. To give the system even more of an edge, the scientists spiked the rich seawater with ATP, a high-energy molecule that drives nearly all of life's reactions today but was unlikely to exist in primordial times.

"Not all of these chemicals might have been available on early Earth, but we're trying to accelerate a process that could in theory get started from even simpler building blocks," says Baum, who is also a discovery fellow at the Wisconsin Institute for Discovery.

The team mixed their primordial soup with fine grains of pyrite, a mineral of iron and sulfur also known as fool's gold. Building on German chemist Günter Wächtershäuser's 1988 proposal of chemical evolution, Baum's team believes that pyrite is an ideal material for cultivating lifelike chemistry.

"Pyrite was a common mineral on primordial Earth, it can bind to a lot of organic compounds, and it can catalyze reactions between them," says Lena Vincent, a graduate student in Baum's lab and the lead author of the study. "And, very elegantly, a lot of highly conserved enzymes across life have cores that are very similar to pyrite. They're basically pyrite wrapped in protein."

The researchers added a few drops of the enriched seawater soup to a small amount of crushed pyrite in a vial and mixed the solution for a few days. This was the first generation. To begin the next generation, Vincent took a small amount of the first solution and mixed it into a vial with fresh soup and pyrite. Over a dozen or more generations, only those chemical networks that could propagate faster than they were diluted would survive and spread.

After 12 or 18 generations, the researchers saw a drop in available phosphate -- a readout of ATP use -- and in the dissolved organic material, which suggested that chemical compounds might be sticking to and spreading along the pyrite grains.

When they inspected the pyrite under ultra-high magnification, the researchers saw an abundance of fractal shapes spreading along the surface of the mineral in the experimental samples but not in control samples that lacked a history of selection.

While these fractal shapes appear to be salts and are not likely to be lifelike themselves, the researchers suspect they may be induced by a thin smear of organic compounds bound to the grains. The fractals never appeared when organic material was left out of the solution.

"Scientists have been looking for examples of reactions that spontaneously complexify and organize organic chemicals for a long time," says Jim Cleaves, a co-author on the work from the Earth-Life Science Institute (ELSI) at the Tokyo Institute of Technology in Japan. "Based on this work, and other experiments we have been conducting at ELSI, it seems possible such reactions may not be incredibly rare at all, it may simply be a matter of using the right tools to find them."

When the researchers ran the experiment out to 40 generations, they observed periods of gradual change interspersed by sudden reversals to the starting conditions. While the cause of these crashes remains unknown, this kind of non-linear feedback loop is found across life and is evidence that the experimental system induced complex behaviors in the chemical soup.

"This non-linearity is a prerequisite for all the interesting lifelike behaviors we're looking for, including self-propagation and evolution," says Vincent.
Cautiously excited with their preliminary success, Baum and his team are now eager to recruit others to help them refine their system.

"We wanted to develop a system that we can probe further to address questions about evolvability. And hopefully other labs will use this protocol and improve it," says Baum. "This is exactly where we wanted to be."

In January of this year, China's Chang'E-4 - the fourth version of a lunar spacecraft named for the Chinese goddess of the Moon - landed on the far side of the Moon. Due to the location of the landing, Chang'E-4 had to navigate autonomously, without the guidance of scientists on Earth.

Now, a research team, headed by LI Chunlai, corresponding author of this results and a professor of the National Astronomical Observatories of Chinese Academy of Sciences (NAOC), has published a full reconstruction of the Chang'E-4's landing. The results appeared on September 24 in Nature Communications.

"This mission had the major challenge of landing on the lunar farside without traditional radio signal techniques due to the missing line-of-sight," said LIU Jianjun, paper author and professor at the Key Laboratory of Lunar and Deep Space Exploration of NAOC. "The landing was successful, and we have now reconstructed the landing trajectory and positioning techniques to better understand the process."

Chang'E-4, which has spent 2019 collecting information about the geology of the Moon's mantle, launched from Earth on December 8, 2018. Once it left Earth's orbit, it circled the Moon before orchestrating a powered descent to the lunar surface, where it navigated itself to the Von Kármán crater, which sits in the South-Pole-Aitken (SPA) basin. The SPA basin stretches about 2,500 kilometers, or about half the width of China. It's the largest known crater in the solar system.

The researchers planned for Chang'E-4 to land in the SPA basin because they're specifically interested in studying the geological composition of the Moon. This is easier to do in areas where impacts may have penetrated past the lunar crust.

The problem was that the SPA basin contains several craters and is surrounded by even more. Previous versions of Chang'E had scouted out the location to a certain extent, so the researchers knew their ultimate landing site goal. However, it was up to Chang'E-4 to navigate around the steeper craters to land in the correct location.

After Chang'E-4 landed, images from the craft's landing camera and navigation camera were transmitted to Earth via the Queqiao satellite. The satellite was launched in 2018 specifically to relay information from Chang'E-4 to Earth.

LI and his team used the images and terrain data from Chang'E-2 to identify the specific location of Chang'E-4, including the elevation down to the meter (-5,935 meters). They also fully reconstructed the path the lander took during its powered descent to the surface, during which it clearly navigated away from steeper craters to areas with flatter terrain.

"It's of great significance to accurately reconstruct the landing trajectory and determine the location of the landing site after a safe landing," LIU said. "We can use this information as landmarks and to service the study of lunar farside control points, high-precision lunar mapping, and future lunar missions."

Every biological reaction is a chemical reaction. The exchange of carbon dioxide for oxygen in our lungs and blood cells, for example, is caused by molecules releasing chemicals and reforming with new ones. The uncontrolled replication of cancerous cells is the result of broken chemical compounds miscommunicating. The appeal of developing improved drugs to promote helpful reactions or prevent harmful ones has driven organic chemists to better understand how to synthetically create these molecules and reactions in the laboratory.

A team from Yokohama National University in Japan has taken a step toward making this wish a reality with their latest study, published on July 19 in the Journal of Organic Chemistry.

The researchers developed oxygen heterocycles, which are ring structures consisting of atoms from two or more elements. These compounds make up all of the nucleic acids in a person's genetic code. Another version of heterocycles, containing nitrogen, are in more than half of the pharmaceuticals produced in the United States. Oxygen heterocycles in particular contain at least one oxygen atom. They have a variety of uses, including in medications to treat cancer and heart failure.

"We focused on oxygen heterocycles, which have attracted significant interest due to the relevance of their structural units in medicinal chemistry and materials science," said Yujiro Hoshino, the study's corresponding author and a research fellow in the Graduate School of Environment and Information Sciences at Yokohama National University.

Professor Kiyoshi Honda, another corresponding author of the study from the Graduate School of Environment and Information Sciences added that their "goal was to develop cost-effective and milder synthetic routes to create oxygen heterocycles."

Traditionally, oxygen heterocycles are made by applying high temperatures to two molecules. The process consumes time and energy, and doesn't produce a significant number of heterocycles. Honda and Hoshino's team focused on a method involving the design of photo-sensitive carbon-based salts. They added the salts to two types of compounds, which form a ring once they react, and irradiated the combination with green light.

"This reaction was particularly attractive because it can hold a high number of atoms and provides efficient access to various synthetically useful oxygen-containing heterocycles," Hoshino said. "This reaction can also be carried out in mild experimental conditions - room temperature and visible light."

The process produced a high yield of oxygen heterocycles. According to Hoshino, the successful reaction was due to a structure on the salts called an electron-donating group. Electrons are excited by green light, and the salts extract an electron from the compound to react with the other compound components.

Next, the researchers plan to turn to different colored light to drive different reactions. They're specifically interested in establishing a red-light reaction, which is more difficult, according to Hoshino. Red light is a longer wavelength and lower frequency than green light, meaning it's closer infrared light than visible light on the spectrum chart. Red-light reactions could drive a higher production of heterocycles, but it requires more accuracy and efficiency.

"Our next goal is to expand the scope of reaction," Hoshino said. "We envision the expansion of the use of various visible-light-driven reactions in the future, and we plan to continue contributing to it."

SAN ANTONIO -- Sept. 18, 2019 -- No one knows for certain when Saturn's iconic rings formed, but a new study co-authored by a Southwest Research Institute scientist suggests that they are much older than some scientists think.

The study takes a closer look at 2017 Cassini spacecraft data that inspired several research papers suggesting that the rings were formed around the time dinosaurs roamed the Earth. Those studies, published in 2018 and 2019, challenged long-held models that put the formation of the rings several billion years earlier, around the time Saturn formed with the rest of the solar system.

In a new twist, SwRI scientist Luke Dones and three French researchers argue that the historic models probably had it right in the first place. The age debate centers around Cassini data from 2017, when the craft revealed a trove of data with dazzling images of Saturn's rings, which are composed of clear, almost pure water ice.

"After Cassini's mission ended, there was a small flood of research that claimed the rings were much younger than we had considered them to be. A common argument was that the rings, if much older, would have become much more polluted as a result of meteoroids crashing into them," Dones said.

A series of studies suggested that the rings would have absorbed portions of dark, dusty material from the meteoroids and gradually become darker. Therefore, the rings would be too bright and clean to have existed in the solar system for billions of years.

Dones and his collaborators, Aurélien Crida of the Université Côte d'Azur, Sébastien Charnoz of the Institut de Physique du Globe de Paris, and Hsiang-Wen Hsu of the University of Colorado, Boulder, pointed out Cassini measurements that show the rings are constantly losing matter to Saturn. The process, which is largely a mystery, could very well be "cleaning" the ice of the rings and making them brighter over time.

Dones and his collaborators state that one of the clearest indications that the rings are old is that their mass is consistent with researchers' current understanding of how primordialrings change. Rings spread with time, spawning satellites at their outer edge and losing mass to Saturn at their inner edge. More massive rings spread faster, so even a very massive primordial ring would be expected to now have the present mass of the rings. If the rings are young, then their current mass would have to be a coincidence.

"It's not impossible to determine the age of the rings, but to do so we'll need a future mission to Saturn that spends a long, intense period studying the rings themselves as well as the relationship between them and the gas giant," Dones said.

Saturn is so beautiful that astronomers cannot resist using the Hubble Space Telescope to take yearly snapshots of the ringed world when it is at its closest distance to Earth.

These images, however, are more than just beauty shots. They reveal a planet with a turbulent, dynamic atmosphere. This year's Hubble offering, for example, shows that a large storm visible in the 2018 Hubble image in the north polar region has vanished. Smaller storms pop into view like popcorn kernels popping in a microwave oven before disappearing just as quickly. Even the planet's banded structure reveals subtle changes in color.

But the latest image shows plenty that hasn't changed. The mysterious six-sided pattern, called the "hexagon," still exists on the north pole. Caused by a high-speed jet stream, the hexagon was first discovered in 1981 by NASA's Voyager 1 spacecraft.

Saturn's signature rings are still as stunning as ever. The image reveals that the ring system is tilted toward Earth, giving viewers a magnificent look at the bright, icy structure. Hubble resolves numerous ringlets and the fainter inner rings.

This image reveals an unprecedented clarity only seen previously in snapshots taken by NASA spacecraft visiting the distant planet. Astronomers will continue their yearly monitoring of the planet to track shifting weather patterns and identify other changes. The second in the yearly series, this image is part of the Outer Planets Atmospheres Legacy (OPAL) project. OPAL is helping scientists understand the atmospheric dynamics and evolution of our solar system's gas giant planets.

In an underground vault enclosed by six-foot concrete walls and accessed by a rolling, 25-ton concrete-and-steel door, University of California, Berkeley, students are making neutrons dance to a new tune: one better suited to producing isotopes required for geological dating, police forensics, hospital diagnosis and treatment.

Dating and forensics rely on a spray of neutrons to convert atoms to radioactive isotopes, which betray the chemical composition of a substance, helping to trace a gun or reveal the age of a rock, for example. Hospitals use isotopes produced by neutron irradiation to kill tumors or pinpoint diseases like cancer in the body.

For these applications, however, only nuclear reactors can produce a strong enough spray of neutrons, and there are only two such reactors west of the Mississippi.

As an alternative, a team including UC Berkeley students has built a tabletop neutron source that would be relatively inexpensive to reproduce and eventually portable and also able to produce a narrower range of neutron energies, minimizing the production of unwanted radioactive byproducts.

"Any hospital in the country could have this thing, they could build it for a few hundred thousand dollars to make local, very short-lived medical isotopes -- you could just run them up the elevator to the patient," said Karl van Bibber, a UC Berkeley professor of nuclear engineering who oversees the students perfecting the device. "It has application in geochronology, neutron activation analysis for law enforcement agencies -- when the FBI wants to determine the provenance of a sample as evidence, for example -- neutron radiography, to look for cracks in aircraft parts. This is very compact, the size of a little convection oven; I think it's great, we are excited about this."

UC Berkeley researchers have now demonstrated that the high flux neutron generator (HFNG) can produce "boutique" neutrons -- neutrons within a very narrow range of energies -- that can be used to accurately date fine-grained rocks nearly impossible to date by other radioisotope techniques. The study will be published this week in the journal Science Advances.

"This will expand the capability of dating fine-grained materials, like clay minerals associated with ore deposits, including gold, or lava flows," said Paul Renne, a UC Berkeley professor-in- residence in the Department of Earth and Planetary Science and director of the Berkeley Geochronology Center. "This device might also let us look at the most primitive objects in our solar system -- calcium/aluminum-rich inclusions found in certain types of meteorites -- which are also very fine-grained."

As they report in the new paper, the researchers used the neutron generator to determine the age of fine-grained lava from the 79 A.D. eruption of Vesuvius, which buried the Roman city of Pompeii. The date they calculated was as precise as the answer given by an exhaustive study in 1997 using state-of-the-art argon-argon dating of samples irradiated at a nuclear reactor.

"It's making it possible to do things that were not possible otherwise," Renne said.

The long road to desktop fusion

Renne has been searching for better ways to irradiate rock samples for decades and heard about one possible method from the late UC Berkeley nuclear engineering professor Stanley Prussin, who died in 2015. The technique involves the fusion of two deuterium atoms, which are isotopes of hydrogen, to produce helium-3 and one neutron. These neutrons have an energy -- about 2.5 million electron volts -- that is ideal for irradiating rocks to conduct argon-argon dating, one of the most precise methods in use today.

Argon-argon dating relies on the fact that about one in every 1,000 potassium atoms in rock is the radioactive isotope potassium-40, which decays to argon-40 with a half-life of more than a billion years. Using neutrons, scientists convert some of the stable potassium, potassium-39, to argon-39, then measure the ratio of Ar-40 to Ar-39 in the sample to calculate its age.

Rock samples must now be irradiated at nuclear reactors, but reactors produce very energetic neutrons that can knock argon atoms out of the sample -- a particular problem for rocks with microscopic grains -- and also produce unwanted radioactive elements. Both effects make age calculation more difficult.

The HFNG avoids both of these problems, because the neutrons are one-tenth the energy of those from a nuclear reactor and have a narrower range of energies, while still maintaining a high flux of neutrons.

"Eliminating the recoil issue, plus reduction of interfering reactions, is huge," Renne said. "But the radiological aspects are also improved."

"The beauty of this thing, we realized, is that you don't have this thing spewing neutrons everywhere and creating a radiological issue," added van Bibber, who is the Shankar Sastry Chair of Leadership and Innovation. "You're actually having a modest number of neutrons, but by getting the target close to the point source -- the thing that matters -- the neutron flux at the sample is very high."

The first device to create neutrons via deuterium-deuterium (D-D) fusion was designed 10 years ago by Renne's team, which included plasma physicist Ka-Ngo Leung, formerly of Lawrence Berkeley National Laboratory (Berkeley Lab). But their prototype languished until van Bibber took an interest in 2012, shortly after his appointment as chair of UC Berkeley's Department of Nuclear Engineering. To house the fusion generator, van Bibber took over a concrete vault formerly used for experiments conducted with the campus's nuclear reactor, which used to sit under what is now Soda Hall -- though it sits in a large underground room that is part of the basement of Etcheverry Hall -- until the reactor closed in 1987 and was removed.

The generator employs about 100,000 volts to accelerate ionized deuterium atoms toward a metal cathode made of titanium. The deuterium accumulates on the cathode in a thin layer that then serves as a target for other incoming ions. When colliding deuterons fuse, a neutron is produced in a broad beam that irradiates the sample located about a third of an inch away.

Over the years, van Bibber enlisted many undergraduates, graduate students and postdoctoral fellows to help make the neutron generator a reality. One of them, transfer student Max Wallace, a rising senior interested in nuclear forensics, was amazed at the access he had to such a machine.

"It's rare to be able to work with radioisotopes as an undergraduate," said the former software engineer. "I learned to do so much late at night, wearing gloves and goggles to measure the radiation, taking samples, doing safety checks and running the software. Really, I'd learn something in my nuclear physics class and then come down here to work on a direct application of it."

For Mauricio Ayllon Unzueta, a fourth-year graduate student in nuclear engineering, the experience he obtained in helping to perfect the neutron generator led directly to a new project at Berkeley Lab: designing a variant of the HFNG that could be taken into the field to do neutron activation of soils to measure carbon content -- a key piece of information if society hopes to sequester carbon in soils to mitigate climate change.

"Through three generations of graduate students, we turned it from something which barely worked into a high performing neutron generator," van Bibber said.

Daniel Rutte, a UC Berkeley postdoctoral researcher in geology working with Renne and BGC lab manager Tim Becker, played a critical role in designing and conducting the first dating experiment, according to Renne.

"Daniel was literally the key player in demonstrating that this would work for Ar-Ar geochronology," he said.

Rutte's goal is to develop new methods and instruments to better understand Earth processes, in particular the deformation of the Earth's crust, which occurs by slow creep or rapid rupture resulting in earthquakes.

"To understand long-term crustal deformation, I date old ruptures preserved in the rock record," Rutte said. "The neutron generator will aid progress in this field by expanding the range of materials we can date."

With ongoing student help, van Bibber and Renne expect to be able to make the neutron generator more compact and to produce a more intense spray of neutrons, making it more broadly useful for geochronology, as well as for other specialized uses. Researchers at UC Berkeley's Space Sciences Laboratory have already shown interest in using these neutrons to test electronic hardware to determine how it will survive in the radioactive environment of space. Higher energy neutrons could be used for neutron radiography, which can complement X-ray radiography in imaging the interior of dense objects, like metals.

"The purpose all along had been to test Paul's dream of whether we could use a very compact, low-voltage device to do neutron irradiation," van Bibber said. "We've now shown that any university can have a neutron source for doing the argon-argon dating technique."

The discovery of a previously unknown species of hadrosaur dinosaur from the Late Cretaceous Period is reported in Scientific Reports this week. The fossil, found in Japan, furthers our understanding of hadrosaur diversity in the Far East and hadrosaurid evolution during the Late Cretaceous Period (100.5-66 million years ago).

Hadrosaurs are among the most successful group of dinosaurs from the Late Cretaceous, and their fossils have been found in North America, South America, Asia, Europe and Antarctica.

Yoshitsugu Kobayashi and colleagues discovered the new hadrosaur, which they have named Kamuysaurus japonicus in marine deposits of the Hakobuchi Formation in Hokkaido, Japan. Its discovery in a marine-influenced environment is rare for hadrosaurs and contributes to understanding of the diversity of hadrosaurids in these environments, the authors suggest.

At around eight metres long, the 72 million-year-old specimen is a middle-sized, fully grown hadrosaur. The authors report a number of unique features, including a small crest on the skull and a short row of neural spines that point forwards. Analysis of this specimen suggests it is related to other hadrosaurs from the Far East such as Laiyangosaurus from China and Kerberosaurus from Russia.

TORONTO, September 5, 2019 - York University researchers have made a precise measurement of the size of the proton - a crucial step towards solving a mystery that has preoccupied scientists around the world for the past decade.

Scientists thought they knew the size of the proton, but that changed in 2010 when a team of physicists measured the proton-radius value to be four percent smaller than expected, which confused the scientific community. Since then, the world's physicists have been scrambling to resolve the proton-radius puzzle - the inconsistency between these two proton-radius values. This puzzle is an important unsolved problem in fundamental physics today.

Now, a study to be published in the journal Science finds a new measurement for the size of the proton at 0.833 femtometres, which is just under one trillionth of a millimetre. This measurement is approximately five percent smaller than the previously-accepted radius value from before 2010.

The study, led by researchers in York University's Faculty of Science, presents a new electron-based measurement of how far the proton's positive charge extends, and it confirms the 2010 finding that the proton is smaller than previously believed.

"The level of precision required to determine the proton size made this the most difficult measurement our laboratory has ever attempted," said Distinguished Research Professor Eric Hessels, Department of Physics & Astronomy, who led the study.

"After eight years of working on this experiment, we are pleased to record such a high-precision measurement that helps to solve the elusive proton-radius puzzle," said Hessels.

The quest to resolve the proton-radius puzzle has far-reaching consequences for the understanding of the laws of physics, such as the theory of quantum electrodynamics, which describes how light and matter interact.

Hessels, who is an internationally-recognized physicist and expert in atomic physics, says three previous studies were pivotal in attempting to resolve the discrepancy between electron-based and muon-based determinations of the proton size.

The 2010 study was the first to use muonic hydrogen to determine the proton size, compared to prior experiments that used regular hydrogen. At the time, scientists studied an exotic atom in which the electron is replaced by a muon, the electron's heavier cousin. While a 2017 study using hydrogen agreed with the 2010 muon-based determination of the proton charge radius, a 2018 experiment, also using hydrogen, supported the pre-2010 value.

Hessels and his team of scientists spent eight years focused on resolving the proton-radius puzzle and understanding why the proton radius took on a different value when measured with muons, rather than electrons.

The York University team studied atomic hydrogen to understand the deviant value obtained from muonic hydrogen. They conducted a high-precision measurement using the frequency-offset separated oscillatory fields (FOSOF) technique, which they developed for this measurement. This technique is a modification of the separated oscillatory fields technique that has been around for almost 70 years and won Norman F. Ramsey a Nobel Prize. Their measurement used a fast beam of hydrogen atoms created by passing protons through a molecular hydrogen gas target. The method allowed them to make an electron-based measurement of the proton radius that is directly analogous to the muon-based measurement from the 2010 study. Their result agrees with the smaller value found in the 2010 study.

A new study from Caltech shows that giant impacts can dramatically lower the internal pressure of planets, a finding that could significantly change the current model of planetary formation.

The impacts, such as the one that is thought to have caused the formation of the earth's moon roughly 4.5 billion years ago, could cause random fluctuations in core and mantle pressures that would explain some puzzling geochemical signatures in Earth's mantle.

"Previous studies have incorrectly assumed that a planet's internal pressure is simply a function of the mass of the planet, and so it increases continuously as the planet grows. What we've shown is that the pressure can temporarily change after a major impact, followed by a longer term increase in pressure as the post-impact body recovers. This finding has major implications for the planet's chemical structure and subsequent evolution," says Simon Lock, postdoctoral researcher at Caltech and lead author of a paper explaining the new model that was published by Science Advances on September 4.

Lock authored the paper with colleague Sarah Stewart (PhD '02), professor of planetary science at the University of California, Davis, a 2018 MacArthur Fellow, and an alumna of the Caltech Division of Geological and Planetary Sciences.

Planetary systems typically begin as a disk of dust that slowly accretes into rocky bodies. The end of the main stage of this process is characterized by high-energy collisions between planet-sized bodies as they coalesce to form the final planets.

The shock energy of these impacts can vaporize significant portions of a planet and even, as is thought to have happened with the impact that formed the moon, temporarily turn the two colliding bodies into a rotating donut of planetary material known as a "synestia," which later cools back into one or more spherical bodies.

Lock and Stewart used computational models of giant impacts and planetary structures to simulate collisions that formed bodies with masses of between 0.9 and 1.1 Earth masses and found that, immediately after a collision, their internal pressures were much lower than had been expected. They found that the decrease in pressure was due to a combination of factors: the rapid rotation imparted by the collision, which generated a centrifugal force that acted against gravity, in essence pushing material away from the spin axis; and the low density of the hot, partially vaporized body.

"We have no direct observations of the growth of Earth-like planets. It turns out that the physical properties of a planet can vary wildly during their growth by collisions. Our new view of planet formation is much more variable and energetic than previous models which opens the door for new explanations of previous data," Stewart says.

The final result is that major impacts can lower a planet's internal pressure significantly. The pressure right after an impact like the one that is thought to have formed the moon could have been half of that of present-day Earth.

If true, the finding could help reconcile a long-standing contradiction between the geochemistry of the earth's mantle and physical models of planet formation.

As the proto-Earth grew, each object that collided with it delivered metal into the mantle. After each impact, the metal absorbed small amounts of other elements from the mantle, and then sank to the core - dragging those elements with it. The amount of each element that dissolved into the metal was determined, in part, by the earth's internal pressures. As such, the chemical composition of the mantle today records the mantle pressure during the planet's formation.

Studies of the metals in the earth's mantle today indicate that this absorption process occurred at pressures found in the middle of the mantle today. However, giant impact models show that such impacts melt most of the mantle, and so the mantle should have recorded a much higher pressure - equivalent to what we now see just above the core. This anomaly between the geochemical observation and physical models is one that scientists have long sought to explain.

By showing that the pressures after giant impacts were lower than previously thought, Lock and Stewart may have found the physical mechanism to solve this conundrum.

Next, Lock and Stewart plan to use their results to calculate how stochastic changes in pressure during formation affect the chemical structure of planets. Lock says that they will also continue to study how planets recover from the trauma of giant impacts "We have shown that the pressures in planets can increase dramatically as a planet recovers, but what effect does that have on how the mantle solidifies or how Earth's first crust formed? This is a whole new area that has yet to be explored," he says.

Jupiter's moon Io is the most volcanically active body in our solar system. Today, there are indications that an active moon outside our solar system, an exo-Io, could be hidden at the exoplanet system WASP-49b. "It would be a dangerous volcanic world with a molten surface of lava, a lunar version of close-in Super Earths like 55 Cancri-e" says Apurva Oza, postdoctoral fellow at the Physics Insitute of the University of Bern and associate of the NCCR PlanetS, "a place where Jedis go to die, perilously familiar to Anakin Skywalker." But the object that Oza and his colleagues describe in their work seems to be even more exotic than Star Wars science fiction: the possible exomoon would orbit a hot giant planet, which in turn would race once around its host star in less than three days - a scenario 550 light years away in the inconspicuous constellation of Lepus, underneath the bright Orion constellation.

Sodium gas as circumstantial evidence

Astronomers have not yet discovered a rocky moon beyond our solar system and it's on the basis of circumstantial evidence that the researchers in Bern conclude that the exo-Io exists: Sodium gas was detected at the WASP 49-b at an anomalously high-altitude. "The neutral sodium gas is so far away from the planet that it is unlikely to be emitted solely by a planetary wind," says Oza. Observations of Jupiter and Io in our solar system, by the international team, along with mass loss calculations show that an exo-Io could be a very plausible source of sodium at WASP 49-b. "The sodium is right where it should be" says the astrophysicist.

Tides keep the system stable

Already in 2006, Bob Johnson of the University of Virginia and the late Patrick Huggins at New York University, USA had shown that large amounts of sodium at an exoplanet could point to a hidden moon or ring of material, and ten years ago, researchers at Virginia calculated that such a compact system of three bodies: star, close-in giant planet and moon, can be stable over billions of years. Apurva Oza was then a student at Virginia, and after his PhD on moons atmospheres in Paris, decided to pick up the theoretical calculations of these researchers. He now publishes the results of his work together with Johnson and colleagues in the Astrophysical Journal.

"The enormous tidal forces in such a system are the key to everything," explains the astrophysicist. The energy released by the tides to the planet and its moon keeps the moon's orbit stable, simultaneously heating it up and making it volcanically active. In their work, the researchers were able to show that a small rocky moon can eject more sodium and potassium into space through this extreme volcanism than a large gas planet, especially at high altitudes. "Sodium and potassium lines are quantum treasures to us astronomers because they are extremely bright," says Oza, "the vintage street lamps that light up our streets with yellow haze, is akin to the gas we are now detecting in the spectra of a dozen exoplanets."

"We need to find more clues"

The researchers compared their calculations with these observations and found five candidate systems where a hidden exomoon can survive against destructive thermal evaporation. For WASP 49-b the observed data can be best explained by the existence of an exo-Io. However, there are other options. For example, the exoplanet could be surrounded by a ring of ionized gas, or non-thermal processes. "We need to find more clues," Oza admits. The researchers are therefore relying on further observations with ground-based and space-based instruments.

"While the current wave of research is going towards habitability and biosignatures, our signature is a signature of destruction", says the astrophysicist. A few of these worlds could be destroyed in a few billion years due to the extreme mass loss. "The exciting part is that we can monitor these destructive processes in real time, like fireworks", says Oza.

When breast cancer cells spread through the body, they do so mainly through the lymph system that normally removes excess fluid and waste products from our tissues. Now, scientists from the group of Professor Massimiliano Mazzone (VIB-KU Leuven Center for Cancer Biology) identified a novel subset of immune cells, called Podoplanin-expressing macrophages (PoEMs), that change the tissues near a tumor in a way that promotes the spreading of cancer cells. Getting rid of these PoEMs in a mouse model strongly reduced the ability of breast cancer cells to move to other parts of the body.

Lymph highways for cancer cells

The lymphatic system drains excessive fluid and removes waste products from our tissues. Lymphatic vessels can also play a role in the spread of breast cancer. Growing tumors often put physical pressure on their environment, which makes these lymphatic vessels leaky and easier accessible for tumor cells.

The cancer cells take advantage of these leaks to move through the body and start growing tumors elsewhere, in a process called metastasis. Previous studies have shown that breast cancer cells prefer to move through the lymph system and that more lymphatic vessels near the tumor correlate with a more dire prognosis for patients.

Therefore, therapies that effectively tackle the development and growth of lymph vessels could reduce metastasis and therefore the death toll from mammary tumors, which remain virtually incurable when not detected on time.

PoEMs that promote metastasis

The development and growth of lymph vessels near tumors is sometimes supported by a certain type of immune cell. In this new study, Pawel Bieniasz-Krzywiec from the Mazzone team identified a subgroup of these cells, called Podoplanin-expressing macrophages (PoEMs).

But what is the importance of the presence of PoEMs in this specific environment? Prof. Mazzone explains: "PoEMs are characterized by a unique gene signature related to changes in the tumor's environment. Specifically, they are an excellent source of Collagen 1, which constitutes the supporting scaffold for growing lymphatic vessels. PoEMs also digest some parts of this environment. This liberates various growth factors that stimulate the formation of lymph vessels and gives rise to new routes for cancer cells dissemination."

The team further observed that PoEMs loosen up the connections between the cells that form the walls of the lymph vessels, which makes it easier for cancer cells to enter these highways. In mice, preventing PoEMs from 'environmental remodeling' highly decreased lymph node and distant organ metastasis.

Blocking PoEMs to fight cancer

These findings provide supportive evidence to targeting PoEMs in humans. With the help of clinicians and pathologists from KU Leuven and UZ Antwerpen, the researchers further tested their findings in human cancer samples. Pawel Bieniasz-Krzywiec provides more details: "On top of the mice results, human breast cancer sample testing revealed a positive correlation between the presence of PoEMs around tumor lymph vessels and lymph node involvement as well as organ metastasis. These observations pave the road towards the use of PoEM blockers in cancer therapy, specifically targeting the cancer-associated lymphatic vessels, without triggering lymphedema associated with current strategies."

From a broader perspective, the study highlights an emerging concept that properties of immune cells are inherently related to the specific environment they reside in. The study of Prof. Mazzone's team describes for the first time a subset of immune cells specifically associated with tumor lymphatics and promoting their growth.

"Our findings change the way we understand lymph vessel growth near tumors and will surely stimulate new and exciting research in the field," Prof. Mazzone concludes.

Maunakea, Hawaii - Astronomers have discovered a planet three times the mass of Jupiter that travels on a long, egg-shaped path around its star. If this planet were somehow placed into our own solar system, it would swing from within our asteroid belt to out beyond Neptune. Other giant planets with highly elliptical orbits have been found around other stars, but none of those worlds were located at the very outer reaches of their star systems like this one.

"This planet is unlike the planets in our solar system, but more than that, it is unlike any other exoplanets we have discovered so far," says Sarah Blunt, a Caltech graduate student and first author on the new study publishing in The Astronomical Journal. "Other planets detected far away from their stars tend to have very low eccentricities, meaning that their orbits are more circular. The fact that this planet has such a high eccentricity speaks to some difference in the way that it either formed or evolved relative to the other planets."

The planet was discovered using the radial velocity method, a workhorse of exoplanet discovery that detects new worlds by tracking how their parent stars "wobble" in response to gravitational tugs from those planets.

However, analyses of these data usually require observations taken over a planet's entire orbital period. For planets orbiting far from their stars, this can be difficult: a full orbit can take tens or even hundreds of years.

The California Planet Search, led by Caltech Professor of Astronomy Andrew W. Howard, is one of the few groups that watches stars over the decades-long timescales necessary to detect long-period exoplanets using radial velocity.

The data needed to make the discovery of the new planet were first provided by W. M. Keck Observatory in Hawaii. In 1997, the team began using the High-Resolution Echelle Spectrometer (HIRES) on the Keck I telescope to take measurements of the planet's star, called HR 5183.

"The key was persistence," said Howard. "Our team followed this star with Keck Observatory for more than two decades and only saw evidence for the planet in the past couple years! Without that long-term effort, we never would have found this planet."

In addition to Keck Observatory, the California Planet Search also used the Lick Observatory in Northern California and the McDonald Observatory in Texas.

The astronomers have been watching HR 5183 since the 1990s, but do not have data corresponding to one full orbit of the planet, called HR 5183 b, because it circles its star roughly every 45 to 100 years. The team instead found the planet because of its strange orbit.

"This planet spends most of its time loitering in the outer part of its star's planetary system in this highly eccentric orbit, then it starts to accelerate in and does a slingshot around its star," explains Howard. "We detected this slingshot motion. We saw the planet come in and now it's on its way out. That creates such a distinctive signature that we can be sure that this is a real planet, even though we haven't seen a complete orbit."

The new findings show that it is possible to use the radial velocity method to make detections of other far-flung planets without waiting decades. And, the researchers suggest, looking for more planets like this one could illuminate the role of giant planets in shaping their solar systems.

Planets take shape out of disks of material left over after stars form. That means that planets should start off in flat, circular orbits. For the newly detected planet to be on such an eccentric orbit, it must have gotten a gravitational kick from some other object.

The most plausible scenario, the researchers propose, is that the planet once had a neighbor of similar size. When the two planets got close enough to each other, one pushed the other out of the solar system, forcing HR 5183 b into a highly eccentric orbit.

"This newfound planet basically would have come in like a wrecking ball," says Howard, "knocking anything in its way out of the system."

This discovery demonstrates that our understanding of planets beyond our solar system is still evolving. Researchers continue to find worlds that are unlike anything in our solar system or in solar systems we have already discovered.

"Copernicus taught us that Earth is not the center of the solar system, and as we expanded into discovering other solar systems of exoplanets, we expected them to be carbon copies of our own solar system," Howard explains, "But it's just been one surprise after another in this field. This newfound planet is another example of a system that is not the image of our solar system but has remarkable features that make our universe incredibly rich in its diversity."

A group of researchers may have found a way to reverse falling crop yields caused by increasingly salty farmlands throughout the world.

Led by Brent Nielsen, professor of microbiology and molecular biology at Brigham Young University, scientists have used bacteria found in the roots of salt-tolerant plants to successfully inoculate alfalfa plants against overly salty soil.

"We take the roots of these salt-tolerant plants (called halophytes), grind them up and grow the bacteria in a petri dish in the lab," Nielsen said. "Doing this, we isolated over 40 different bacteria isolates, some of which can tolerate ocean-level salt content."

The team then applied the bacteria isolates to alfalfa seeds through a solution and tested the alfalfa's ability to grow in high-saline conditions. They saw significant growth of the alfalfa both in their lab and in greenhouse experiments carried out by collaborators at the Institute for Advanced Learning and Research in Virginia.

The study identifies two specific bacteria isolates -- Halomonas and Bacillus -- that worked to stimulate plant growth in the presence of 1 percent sodium chloride (salt), a level that significantly inhibits growth of uninoculated plants. This discovery is significant since soils throughout areas of China, Australia and the Middle East have grown increasingly salty, as well as major farmland in the southwest United States.

"As an area of land is repeatedly used for farming, the salinity rises; the irrigation water has salt in it and when it evaporates or is taken up by the plants, the salt is left behind," said student Caitlyn McNary, one of six BYU undergraduate co-authors on the paper. "With what we've found, lands that are now unable to sustain plant life due to high salinity could once again be used for crops."

In addition to the work on alfalfa, America's No. 4 crop, the research team has already started to conduct lab and greenhouse experiments on rice, green beans and lettuce. The next step is to carry out field trials on the inoculated crops.

The lab work for the research, recently published online in Frontiers in Microbiology, was carried out primarily by six BYU undergraduate students: McNary and fellow first author Jennifer Kearl, Emily Colton, Steven Smith, Jason West and Michelle Hamson. BYU Plant and Wildlife professor Zachary Aanderud, and Scott Lowman and Chuansheng Mei of the Plant Endophyte Research Center also served as a study co-authors.

"We've long wondered if increasingly salty land was just a losing battle or if there was something we could do about it," Nielsen said. "Now we have shown there is something we can do about it."