Heavens

The newly-discovered dark dwarf galaxy Antlia 2's collision with the Milky Way may be responsible for our galaxy's characteristic ripples in its outer disc, according to a study led by Rochester Institute of Technology Assistant Professor Sukanya Chakrabarti.

The Antlia 2 dwarf galaxy was discovered from the second data release of the European Space Agency's Gaia mission, which aims to chart a three-dimensional map of our galaxy. Antlia 2's current location closely matches the location of a dark-matter dominated dwarf galaxy that Chakrabarti predicted in 2009 through a dynamical analysis. Using the Gaia data, Chakrabarti calculated its past trajectory and found that Antlia 2 would have crashed into the Milky Way and produced the large ripples that we see in the outer gas disc of our galaxy.

Upcoming additional data releases from Gaia will provide further clarity, and Chakrabarti said that she and her team have made "a hand-on-the-cutting-board kind of prediction of what to expect for the motion of the stars in the Antlia 2 dwarf galaxy in future Gaia data releases." Chakrabarti said the discovery could help develop methods to hunt for dark galaxies and ultimately solve the long-standing puzzle of what dark matter is.

"We don't understand what the nature of the dark matter particle is, but if you believe you know how much dark matter there is, then what's left undetermined is the variation of density with radius," said Chakrabarti. "If Antlia 2 is the dwarf galaxy we predicted, you know what its orbit had to be. You know it had to come close to the galactic disc. That sets stringent constraints, therefore, on not just on the mass, but also its density profile. That means that ultimately you could use Antlia 2 as a unique laboratory to learn about the nature of dark matter."

The researchers also explored other potential causes for the ripples in the Milky Way's outer disc, but ruled out the other candidates. The Sagittarius dwarf galaxy's tidal strength was insufficient and the Large and Small Magellanic Clouds are too distant. The evidence points to Antlia 2 as the most likely cause.

Chakrabarti presented her findings at the 234th meeting of the American Astronomical Society in St. Louis, Mo., on Wednesday, June 12.

The Solar System's second largest planet both in mass and size, Saturn is best known for its rings. These are divided by a wide band, the Cassini Division, whose formation was poorly understood until very recently. Now, researchers* from the CNRS, the Paris Observatory - PSL and the University of Franche-Comté have shown that Mimas, one of Saturn's moons, acted as a kind of remote snowplough, pushing apart the ice particles that make up the rings. The findings are the result of two studies supported by the International Space Science Institute and CNES, the French space agency, published simultaneously in June 2019 in Monthly Notices of the Royal Astronomical Society.

Saturn's rings are made up of ice particles whose orbital velocity increases the closer they are to the planet. The Cassini Division is a wide, dark band located between Saturn's two most visible rings, in which the particle density is considerably lower than that inside the rings. The researchers suspected a link between Mimas, one of Saturn's moons, and the band, since there is a region at the inner edge of the Division where the particles orbit around Saturn exactly twice as fast as Mimas. This phenomenon, known as orbital resonance, pushes the ice particles apart, producing a relatively narrow gap. Scientists from CNRS, the Paris Observatory - PSL and the University of Franche-Comté have now shown that Mimas may have moved closer to Saturn in the recent past, making the moon a kind of remote snowplough that widened the initial gap, giving it the 4500 km width it has today. If on the other hand the orbit of Mimas moved outwards, the particles would return to their original position, rather as if a snowplough were to reverse and stop pushing the snow, letting it spread out again. Using numerical simulations, the researchers calculated that Mimas must have migrated inwards by 9000 km over a few million years in order to open up the 4500 km gap that currently makes up the Cassini Division.

A natural satellite, such as the Moon, normally tends to move away from its planet rather than closer to it. In order to migrate inwards, a moon has to be able to lose energy, particularly by heating up, which would cause its internal ice to melt and weaken its outer crust. However, the state of Mimas' surface, which still bears the scars of relatively ancient meteorite impacts, does not tally with such a scenario. The researchers' second hypothesis, which remains to be confirmed, is that the loss of heat was shared out between Mimas and Enceladus, another of Saturn's moons, through orbital resonance. This would have caused the creation of the internal oceans that the Cassini spacecraft detected below the surface of both these bodies.

Today, Mimas has begun to migrate outwards again. According to the researchers' calculations, the Cassini Division is likely to take around 40 million years to close up again. Thanks to these findings, scientists may view the presence of gaps in the rings of an exoplanet as a clue that it could have moons with oceans.

A mysterious large mass of material has been discovered beneath the largest crater in our solar system -- the Moon's South Pole-Aitken basin -- and may contain metal from the asteroid that crashed into the Moon and formed the crater, according to a Baylor University study.

"Imagine taking a pile of metal five times larger than the Big Island of Hawaii and burying it underground. That's roughly how much unexpected mass we detected," said lead author Peter B. James,

Ph.D., assistant professor of planetary geophysics in Baylor's College of Arts & Sciences.
The crater itself is oval-shaped, as wide as 2,000 kilometers -- roughly the distance between Waco, Texas, and Washington, D.C. -- and several miles deep. Despite its size, it cannot be seen from Earth because it is on the far side of the Moon.

The study -- "Deep Structure of the Lunar South Pole-Aitken Basin" -- is published in the journal Geophysical Research Letters.

To measure subtle changes in the strength of gravity around the Moon, researchers analyzed data from spacecrafts used for the National Aeronautics and Space Administration (NASA) Gravity Recovery and Interior Laboratory (GRAIL) mission.

"When we combined that with lunar topography data from the Lunar Reconnaissance Orbiter, we discovered the unexpectedly large amount of mass hundreds of miles underneath the South Pole-Aitken basin," James said. "One of the explanations of this extra mass is that the metal from the asteroid that formed this crater is still embedded in the Moon's mantle."

The dense mass -- "whatever it is, wherever it came from" -- is weighing the basin floor downward by more than half a mile, he said. Computer simulations of large asteroid impacts suggest that, under the right conditions, an iron-nickel core of an asteroid may be dispersed into the upper mantle (the layer between the Moon's crust and core) during an impact.

"We did the math and showed that a sufficiently dispersed core of the asteroid that made the impact could remain suspended in the Moon's mantle until the present day, rather than sinking to the Moon's core," James said.

Another possibility is that the large mass might be a concentration of dense oxides associated with the last stage of lunar magma ocean solidification.

James said that the South Pole-Aitken basin -- thought to have been created about 4 billion years ago -- is the largest preserved crater in the solar system. While larger impacts may have occurred throughout the solar system, including on Earth, most traces of those have been lost.

James called the basin "one of the best natural laboratories for studying catastrophic impact events, an ancient process that shaped all of the rocky planets and moons we see today."

Moons orbiting planets outside our solar system could offer another clue about the pool of worlds that may be home to extra-terrestrial life, according to an astrophysicist at the University of Lincoln.

Exoplanets are planets outside our solar system and up to this point nearly 4,000 have been discovered. Only a small proportion of these are likely to be able to sustain life, existing in what is known as the habitable zone. But some planets, especially large gas giants, may harbour moons which contain liquid water.

Dr Sutton said: "These moons can be internally heated by the gravitational pull of the planet they orbit, which can lead to them having liquid water well outside the normal narrow habitable zone for planets that we are currently trying to find Earth-like planets in. I believe that if we can find them, moons offer a more promising avenue to finding extra-terrestrial life."

This interest has inspired Dr Sutton's latest research, which looked at the possibility of moons orbiting the exoplanet J1407b, analysing whether they may have caused gaps in the planet's ring system.

Because of their size and distance from Earth, exomoons are very difficult to detect. Scientists have to locate them by looking for the effect they have on objects around them, such as planetary rings.

Dr Sutton ran computer simulations to model the rings around J1407b, which are 200 times larger than those around Saturn. Gravitational forces between all particles were calculated and used to update the positions, velocities and accelerations in the computer models of the planet and its ring system. He then added a moon that orbited at various ratios outside of the rings to test whether this caused gaps to form where expected over 100 orbital periods.

Findings revealed that while the orbiting moon did have an effect on the scattering of particles along the ring edge, the expected gaps in the ring structure were unlikely to be caused by the gravitational forces of a currently unseen moon orbiting outside the rings.

Belgian research groups from the VIB, Ghent University, Ghent University Hospital, and the biotech company argenx have solved a century-long puzzle about the presence of protein crystals in asthma. Normally, proteins do not crystallize in the body, but there are some instances where this process does occur. Charcot-Leyden Crystals are made from the protein Galectin-10 and were discovered in the airways of asthmatics as early as 1853. However, the crystals have been largely ignored by scientists, and their actual link to disease remained unknown. The Belgian research groups have now established that the crystals are highly abundant in airway mucus, stimulate the immune system and promote the inflammation and altered mucus production that is often seen in the airways of asthmatics. Together the academic and company scientists also developed antibodies that can dissolve these crystals to reduce key asthma features. Such antibodies could be first-in-class therapeutics that reverse protein crystals and treat asthma and other chronic inflammatory diseases of the airways. The study is published in the leading journal Science.

Crystals and disease

In 1853, Jean-Martin Charcot at the renowned Salpêtrière Hospital in Paris reported detailed sketches of bipyramidal crystals that he had observed in the sputum of patients suffering from asthma, an observation also made by Ernst von Leyden in 1872. These crystalline deposits became widely known as Charcot-Leyden crystals (CLCs) in the medical world. Since then, they have been described in widespread chronic allergic and inflammatory diseases such as asthma, bronchitis, allergic rhinitis, and rhinosinusitis. It was, however, only during r the last couple of decades that the content of CLCs was confirmed as being made up of the protein galectin-10, finally settling speculations and debates that lasted for nearly a century and a half. Galectin-10 is one of the most abundant proteins in eosinophils, which help to mount an inflammatory response in humans. Surprisingly, Gal10 remains largely soluble in eosinophils and it only forms crystals once it has been released as part of an immunological defense. The function of Gal10 also remained elusive.

Do these crystals cause harm?

Spearheaded by Emma Persson, Kenneth Verstraete, and Ines Heyndrickx, the team of researchers set out to test a longstanding unresolved hypothesis: do CLCs stimulate immunity in the lung and contribute to excessive inflammatory responses leading to disease?

Prof. Bart Lambrecht (VIB-UGent): "Every medical doctor learns about Charcot-Leyden Crystals during medical training and everybody associates such crystals with the presence of eosinophils. They are very often found in the sputum of asthma patients, particularly in those patients with severe disease. Yet nobody really knew what these crystals were doing and why they are there in the first place. By analogy with the disease gout -where uric acid crystals cause a very painful attack of joint inflammation- we reasoned that Charcot-Leyden crystals might also cause harm in the lungs of asthma patients"

Crystals versus solution

There were a lot of technical challenges to overcome to test this idea. The scientists had to find a way to produce millions of crystals of Gal10 in the laboratory for research purposes and established these were identical to CLCs found in patients. The researchers used precious patient-derived crystals to determine the three-dimensional structure of Gal10 down to the atomic scale. This provided a 'holy-grail' kind of answer that confirmed that experimentally produced CLCs are identical to patient-derived CLC.

Prof. Savvas Savvides (VIB-UGent): "This is the first time in biochemical and medical history that patient-derived protein crystals are studied at atomic resolution. It is utterly remarkable that such microscopic crystals, which are merely a few micrometers in size (about a thousandth of a millimeter) survived the laborious and harsh experimental path that started in a hospital operation theater and ended at a specialized X-ray beamline of a European synchrotron radiation facility. And to top it off they yielded data that lead to a beautiful three-dimensional structure of the protein molecules inside them".

The researchers found that Gal10 induced a fully blown immune response only when it was in the crystalline state. In solution, Gal10 was harmless. Most importantly, crystalline Gal10 in the form of Charcot-Leyden crystals induced key features of asthma, including the production of altered mucus that is a big problem for most asthmatics. Thus, the study already delivered a major breakthrough with crystal clear conclusions.

Looking for a solution

The group then studied if interfering with CLC formation would be a therapeutic option for asthmatics. This is exactly where argenx, a Ghent-based biotechnology company stepped in. The combined teams developed antibodies that can react specifically against CLC. Remarkably, the antibodies were able to dissolve CLC within minutes in a petri dish in the lab and within a few hours in the mucus of patients (also in vitro). Use of these antibodies in mouse models of asthma lead to a strong reduction of lung inflammation, lung function alterations and mucus production.

Prof. Savvides: "It was like a 'now you see it, now you don't' display of molecular magic. I have spent 25 years learning and agonizing about how to grow protein crystals for structural biology, and all of a sudden, I was seeing protein crystals dissolve in real time! And to top it off we also got to visualize how these antibodies actually do their magic by determining their crystal structure in complex with their antigen!"

Prof. Bart Lambrecht: "Our research results were unexpected and crystal clear at the same time. I was completely struck by the fact that antibodies can rapidly dissolve CLCs that are so abundantly present in the native mucus of patients. Although more tests are needed, the data in mouse models suggest that use of these antibodies could be a very effective way of reducing excessive inflammation and mucus accumulation in the lungs of patients with asthma. Since there are no drugs currently targeting mucus accumulation in the airways, this could be a game changer for treating this disease."

In the strongly correlated materials such as cuprate high-temperature superconductors, superconductivity can be controlled either by changing the number of electrons or by changing the kinetic energy, or transfer energy, of electrons in the system.Although a large number of strongly correlated materials have been examined with different parameters to understand the mechanism of superconductivity, the range of parameter control is always limited. A versatile experimental method to achieve simultaneous control of the number and the transfer energy of the electrons has been long desired.

A flexible electric-double-layer transistor (EDLT), or "correlated" transistor, composed of an organic strongly correlated material was constructed (Fig. 1) by researchers at RIKEN, Institute for Molecular Science (IMS), Nagoya University and Toho University. The number of electrons can be controlled by gate voltages of the EDLT, and the transfer energy of electrons can be controlled by bending the EDLT substrate. They found that the system changed from an insulator to a superconductor in both cases of increasing and decreasing electron numbers. Conditions for these superconducting states in the above two cases, however, were found to be fundamentally different. In addition, another superconducting state emerged when the substrate was bent. The present result was published online on Science Advances on May 10, 2019.

Researchers fabricated the EDLT using a crystal of the organic strongly correlated material made of BEDT-TTF (bis(ethylenedithio)tetrathiafulvalene) molecules (Fig. 1). By applying the gate voltage on to the surface of the crystal, the number of electrons can be increased (electron doping) and decreased (hole doping). This EDLT device is flexible, and the transfer energy can be controlled by applying mechanical force (strain) from the back side of the EDLT. The researchers successfully controlled superconductivity in an identical sample, by precisely changing both the gate voltage and the strain.

Figure 2 shows the regions of superconducting states. The abscissa shows the gate voltage, which corresponds to the number of doped electrons. The ordinate shows the strain applied to the device by bending. With going down along the ordinate, the electrons move more easily because the kinetic energy of electrons increases. The region of the insulating state (red) is surrounded by the regions of superconducting states (blue). Two superconducting regions of the left and the right sides of the insulating region are significantly different in shape on Fig. 2. Especially the superconducting state appeared with an increasing number of electrons (the right side on Fig. 2) shows remarkable behavior that the state appeared suddenly with a few percent increase of the number of electrons and disappeared with an addition of excess electrons. The superconducting states can be obtained both by increasing and by decreasing electron numbers. However, the features of the two states are found to be fundamentally different.

The two-dimensional phase diagram (Fig. 2) was thus obtained using the single sample. The diagram shows the nature of the superconducting phase transition, which has been anticipated from data collected from many different samples before this device appears. Therefore this newly developed experimental method accelerates to obtain the phase diagrams. More fundamentally, drawing the full phase diagram from the same sample enables us to obtain more reliable results regardless of the effects of impurity and of difference in crystal structures.

This experimental method can apply to various organic strongly correlated materials. One interesting example is the quantum spin liquid in which the directions of electron spins are moving randomly even at 0 Kelvin. Experiments on the quantum spin liquid will reveal the relationship between superconductivity and magnetism (arrangement of electron spins). It is also notable that the phase diagram of strongly correlated electron system is a significant target of quantum simulators. The present result provides one possible standard solution for those newly developing calculation methods.

The Earth's magnetic shield booms like a drum when it is hit by strong impulses, according to new research from Queen Mary University of London.

As an impulse strikes the outer boundary of the shield, known as the magnetopause, ripples travel along its surface which then get reflected back when they approach the magnetic poles.

The interference of the original and reflected waves leads to a standing wave pattern, in which specific points appear to be standing still while others vibrate back and forth. A drum resonates like this when struck in exactly the same way.

This study, published in Nature Communications, describes the first time this effect has been observed after it was theoretically proposed 45 years ago.

Movements of the magnetopause are important in controlling the flow of energy within our space environment with wide-ranging effects on space weather, which is how phenomena from space can potentially damage technology like power grids, GPS and even passenger airlines.

The discovery that the boundary moves in this way sheds light on potential global consequences that previously had not been considered.

Dr Martin Archer, space physicist at Queen Mary University of London, and lead author of the paper, said: "There had been speculation that these drum-like vibrations might not occur at all, given the lack of evidence over the 45 years since they were proposed. Another possibility was that they are just very hard to definitively detect.

"Earth's magnetic shield is continuously buffeted with turbulence so we thought that clear evidence for the proposed booming vibrations might require a single sharp hit from an impulse. You would also need lots of satellites in just the right places during this event so that other known sounds or resonances could be ruled out. The event in the paper ticked all those quite strict boxes and at last we've shown the boundary's natural response."

The researchers used observations from five NASA THEMIS satellites when they were ideally located as a strong isolated plasma jet slammed into the magnetopause. The probes were able to detect the boundary's oscillations and the resulting sounds within the Earth's magnetic shield, which agreed with the theory and gave the researchers the ability to rule out all other possible explanations.

Many impulses which can impact our magnetic shield originate from the solar wind, charged particles in the form of plasma that continually blow off the Sun, or are a result of the complicated interaction of the solar wind with Earth's magnetic field, as was technically the case for this event.

The interplay of Earth's magnetic field with the solar wind forms a magnetic shield around the planet, bounded by the magnetopause, which protects us from much of the radiation present in space.

Other planets like Mercury, Jupiter and Saturn also have similar magnetic shields and so the same drum-like vibrations may be possible elsewhere.

Further research is needed to understand how often the vibrations occur at Earth and whether they exist at other planets as well. Their consequences also need further study using satellite and ground-based observations.

On Jan. 30 2019, Lunar Reconnaissance Orbiter Camera (LROC) acquired a spectacular limb shot centered on the Chang'e 4 landing site, looking across the floor of Von Kármán crater. At the time, the Lunar Reconnaissance Orbiter (LRO) was more than 200 kilometers from the landing site so Chang'e 4 was only a few pixels across and the rover was not discernable. The following day LRO was closer to the site and again slewed (59 degrees this time) to capture another view. This time the small Yutu-2 rover shows up (two pixels) just north of the lander. Also, shadows cast by the lander and rover are now visible.

At some time after the formation of Von Kármán crater, the crater floor was covered by eruptions of basaltic lava, similar to the eruptions in Hawaii last summer. Chang'e 4 will collect compositional measurements of these farside basaltic rocks, and lunar scientists are anxiously awaiting these results. Do volcanic rocks on the farside differ from the basalts collected from the nearside? We will have to wait and see!

A striking aspect of the floor of Von Kármán crater is the number and variety of impact craters. There is a high density of craters because the surface is more than 3 billion years old! During those 3 billion years, so many small craters (1000 meters (3280 feet) diameter), which are not in equilibrium, continue to increase in density and can be used to estimate the age of the surface.

Note also all of the small craters that have formed on top of larger ones. Smaller impacts wear down and degrade larger craters over time. You can easily see a wide variety of crater degradation states, ranging from sharp and crisp (new) to highly degraded (old). As result of all of these impacts (small and large), the surface of the Moon consists of a very fine powder known as regolith, in which the Apollo astronauts made their distinct boot prints.

LROC is a system of three cameras mounted on LRO that capture high resolution photos of the lunar surface.

New research undertaken at Northumbria University, Newcastle shows that the Sun's magnetic waves behave differently than currently believed.

Their findings have been reported in the latest edition of the prominent journal, Nature Astronomy.

After examining data gathered over a 10-year period, the team from Northumbria's Department of Mathematics, Physics and Electrical Engineering found that magnetic waves in the Sun's corona - its outermost layer of atmosphere - react to sound waves escaping from the inside of the Sun.

These magnetic waves, known as Alfvénic waves, play a crucial role in transporting energy around the Sun and the solar system. The waves were previously thought to originate at the Sun's surface, where boiling hydrogen reaches temperatures of 6,000 degrees and churns the Sun's magnetic field.

However, the researchers have found evidence that the magnetic waves also react - or are excited - higher in the atmosphere by sound waves leaking out from the inside of the Sun.

The team discovered that the sound waves leave a distinctive marker on the magnetic waves. The presence of this marker means that the Sun's entire corona is shaking in a collective manner in response to the sound waves. This is causing it to vibrate over a very clear range of frequencies.

This newly-discovered marker is found throughout the corona and was consistently present over the 10-year time-span examined. This suggests that it is a fundamental constant of the Sun - and could potentially be a fundamental constant of other stars.

The findings could therefore have significant implications for our current ideas about how magnetic energy is transferred and used in stellar atmospheres.

Dr Richard Morton, the lead author of the report and a senior lecturer at Northumbria University, said: "The discovery of such a distinctive marker - potentially a new constant of the Sun - is very exciting. We have previously always thought that the magnetic waves were excited by the hydrogen at the surface, but now we have shown that they are excited by these sound waves. This could lead to a new way to examine and classify the behaviour of all stars under this unique signature. Now we know the signature is there, we can go looking for it on other stars.

"The Sun's corona is over one hundred times hotter than its surface and energy stemming from the Alfvénic waves is believed to be responsible for heating the corona to a temperature of around one million degrees. The Alfvénic waves are also responsible for heating and accelerating powerful solar wind from the Sun which travels through the solar system. These winds travel at speeds of around a million miles per hour. They also affect the atmosphere of stars and planets, impacting on their own magnetic fields, and cause phenomena such as aurora."

Dr Morton added: "Our evidence shows that the Sun's internal acoustic oscillations play a significant role in exciting the magnetic Alfvénic waves. This can give the waves different properties and suggests that they are more susceptible to an instability, which could lead to hotter and faster solar winds."

The research was funded by the UK Science and Technology Facilities Council and the US Air Force Office of Scientific Research. It was undertaken by Dr Morton and Professor James McLaughlin from Northumbria's Solar Physics research group, together with Dr Micah Weberg, who recently moved from Northumbria to Washington DC's Naval Research Laboratory.

Dr Morton and Professor McLaughlin are currently working with NASA to analyse images of the Sun which were taken by NASA's High-Resolution Coronal Imager, Hi-C.

WASHINGTON-(Jan. 25, 2019)-Mutations in a gene known as interferon regulatory factor 6 (IRF6) that cause cleft lip and palate also are implicated in neural tube defects such as spina bifida, suggests research by an international study team published online Jan. 25, 2019, in Human Molecular Genetics.

In the first weeks of fetal development the neural plate curves, creating a neural tube that, once fused shut, becomes the fetal brain and fetal spinal cord. Neural tube defects, which can range from mild to severe, are characterized by incomplete development of the brain, spinal cord or meninges. These defects can potentially result in paralysis or even fetal or neonatal demise. According to the National Institutes of Health, spina bifida, which affects the spinal cord, is the most common neural tube defect in the U.S., affecting up to 2,000 infants each year.

"Despite its high frequency, spina bifida remains among the least understood structural birth defects," says Brian C. Schutte, an associate professor of Microbiology and Molecular Genetics, Pediatrics and Human Development at Michigan State University and the study's senior author. "There is strong evidence that genetic factors are a leading cause of such structural birth defects, but in most cases, the cause is unknown. Our team's study is the first published research to demonstrate that DNA variants in the gene IRF6 can cause spina bifida," Schutte says.

What's more, the research team identified a mechanism to explain how altering IRF6 leads to neural tube defects. This mechanism links IRF6 function to two other genes--known as transcription Factor AP2A (TFAP2A) and Grainyhead Like 3 (GRHL3)--that are also known to be required for the development of the neural tube, lip and palate.

"We're all on the hunt for the reasons when, how and why birth defects happen," adds Youssef A. Kousa, MS, D.O., Ph.D., a clinical fellow in the Division of Child Neurology at Children's National Health System and the study's lead author. "Our main goal is prevention. This paper is a significant development because our team has identified a group of genes that can potentially contribute to very common types of birth defects: craniofacial as well as neural tube defects."

The scientific odyssey is a wonderful example of serendipity. Kousa, then working in Schutte's lab, was studying the effects of a new mutant experimental model strain on development of the palate. But one day, he walked into Schutte's office holding a deformed preclinical embryo and said: "Brian, look at this!"

"Weird things happen in biology," Schutte replied and counseled him to return if it happened again. Less than two weeks later, Kousa was back with several more of the deformed preclinical embryos, saying: "OK, Brian. It happened again."

Within hours Kousa had unearthed recently published research that included an image of a similarly affected preclinical embryo. The pair then sketched out possible intersecting genetic pathways, as they brainstormed the myriad ways to end up with that specific phenotype. Initially, they tested their hypotheses in experimental models and eventually corroborated findings through human genetic studies. The human studies could only be performed by collaborations. Schutte shared their initial observations with human genetics researchers scattered across the country. Those labs then generously agreed to test whether DNA variants in IRF6 were associated with neural tube defects in samples from patients that they had collected over decades of research.

The team found that Tfap2a, Irf6 and Grhl3 are components of a gene regulatory network required for neurulation, a folding process that results in the neural tube bending and then fusing to become the basis of the embryo's nervous system, from brain to spinal cord.

"Since this network is also required for formation of the lip, palate, limbs and epidermis, which develop at different times and places during embryogenesis, we suggest that the Tfap2a-Irf6-Grhl3 network is a fundamental pathway for multiple morphogenetic processes," the researchers write.

Interferon regulatory factor 6 functions best when there is neither too much expression nor too little. Overexpression of Irf6 suppresses Transcription Factor Activation Protein 2A and Grainyhead Like 3, causing exencephaly, a neural tube defect characterized by the brain being located outside of the skull. Counterintuitively, experimental models that had too little Irf6 also ended up with reduced levels of Tfap2a and Grhl3 that led to a structural birth defect, but at the opposite end of the neural tube.

To test whether the experimental model findings held true in humans, they sequenced samples from people who had spina bifida and anencephaly - the rare birth defect that Kousa spotted in the experimental models - and found IRF6 function was conserved in people. Because of the genetic complexity of these birth defects, and the challenges inherent in collecting samples from cases of severe birth defects, many research teams were invited to participate in the study.

As testament to their collegiality, researchers from Stanford University, University of Texas at Austin, University of Iowa, University of Texas at Houston and Duke University agreed to share precious samples from the California Birth Defects Monitoring Program, from the Hereditary Basis of Neural Tube Defects study and from their own institutional sample collections.

"As we get better at personalized medicine, we could use this information to one day help to counsel families about their own risk and protective factors," Kousa adds. "If we can identify the genetic pathway, we might also be able to modify it to prevent a birth defect. For example, prenatal supplementation with folic acid has led to a decrease in babies born with neural tube defects, but not all neural tube defects are sensitive to folic acid. This knowledge will help us develop individual-based interventions."

WASHINGTON (Jan. 17, 2019)--Gamma-ray bursts are the most powerful explosions in the cosmos. These explosions last several seconds and emit the same amount of light as nearly all the stars in the universe. Such extreme amounts of energy can only be released during catastrophic events like the death of a very massive star, and also produce visible supernovae or hypernovae, the latter being 5 to 50 times more energetic than supernovae.

While the connection between GRBs and hypernovae has been well established, it is still unclear why some hypernovae do not have associated GRBs. Through the detailed observation of a rare, nearby hypernova, an international team of researchers including Chryssa Kouveliotou, a professor of physics at the George Washington University, discovered the missing link connecting hypernovae to GRBs in the form of a hot cocoon around the jets of matter expelled by the central engine as these spread through the outer layers of the progenitor star.

"For a handful of hypernovae not accompanied by GRBs, an excess of high velocity material had been observed in their optical spectra, which had been attributed to a thermal cocoon, namely a jet which never managed to break out of the interior to the surface of its progenitor star," Dr. Kouveliotou said. "With this recent event, we showed the jet provided a significant part of its energy to the cocoon, which allowed both the jet and the gamma rays to break out of the surface of the star. This was the first time we actually got to peek directly at the core of a collapsing massive star!"

The new discovery was announced in the study, "Signatures of a jet cocoon in early spectra of a supernova associated with a γ-ray burst," published today in the journal Nature. The international team was led by Luca Izzo, a researcher at the Institute of Astrophysics of Andalusia in Spain. Dr. Kouveliotou was one of two researchers on the team based in the United States.

On December 5, 2017, the researchers discovered a long-duration GRB in a spiral galaxy about 500 million light-years from Earth, the fourth closest long-duration GRB ever observed. Since this GRB, labeled 171205A, was so close to Earth and detected so early, they were able to monitor the evolution of the source daily with the largest telescopes on the globe. This collaborative effort allowed researchers to capture an unprecedented level of information about the event in many different wavelengths over time.

Within the first days after the GRB detection, evidence of the presence of a hypernova was reported, but the findings were very peculiar. Hypernovae are characterized by high expansion velocities on the order of 30,000 kilometers per second, but the hypernova the researchers observed--designated SN 2017iuk--had a much higher velocity, more than 100,000 kilometers per second in the first few hours after the explosion. A detailed analysis of the multi-wavelength emission observed in the very early days of SN 2017iuk led to surprising results.

"We first noticed a peculiar component, which showed very high velocity and unusual chemical composition not seen previously in similar events," Dr. Kouveliotou explained. "These features fit perfectly with the assumption that we observe material from the central engine escaping from the GRB progenitor star.

The team did in fact observe a hot cocoon taking material from the interior of the star to the outer layers. After about three days, the hot cocoon faded away and the hypernova began behaving similarly to those observed previously. The researchers indicated the energy emitted by the cocoon in the earliest days of the hypernova was larger than that of the GRB, implying the jet deposited the bulk of its energy into the cocoon. These results demonstrate choked jets are indeed the reason some hypernovae do not seem to be associated with GRBs.

The researchers noted the findings have interesting consequences for how supernova and hypernova explosion models are constructed in the future.

New research led by astrophysicists at Durham University, UK, predicts that the Large Magellanic Cloud (LMC) could hit the Milky Way in two billion years' time.

The collision could occur much earlier than the predicted impact between the Milky Way and another neighbouring galaxy, Andromeda, which scientists say will hit our galaxy in eight billion years.

The catastrophic coming together with the Large Magellanic Cloud could wake up our galaxy's dormant black hole, which would begin devouring surrounding gas and increase in size by up to ten times.

As it feeds, the now-active black hole would throw out high-energy radiation and while these cosmic fireworks are unlikely to affect life on Earth, the scientists say there is a small chance that the initial collision could send our Solar System hurtling into space.

The findings are published today (Friday, 4 January) in the journal Monthly Notices of the Royal Astronomical Society.

Galaxies like our own Milky Way are surrounded by a group of smaller satellite galaxies that orbit around them, in a similar way to how bees move around a hive.

Typically, these satellite galaxies have a quiet life and orbit around their hosts for many billions of years. However, from time to time, they sink to the centre, collide and are devoured by their host galaxy.

The Large Magellanic Cloud is the brightest satellite galaxy of the Milky Way and only entered our neighbourhood about 1.5 billion years ago. It sits about 163,000 light years from the Milky Way.

Until recently astronomers thought that it would either orbit the Milky Way for many billions of years, or, since it moves so fast, escape from our galaxy's gravitational pull.

However, recent measurements indicate that the Large Magellanic Cloud has nearly twice as much dark matter than previously thought. The researchers say that since it has a larger than expected mass, the Large Magellanic Cloud is rapidly losing energy and is doomed to collide with our galaxy.

The research team, led by scientists at Durham University's Institute for Computational Cosmology working with the University of Helsinki, in Finland, used the EAGLE galaxy formation supercomputer simulation to predict the collision.

Lead author Dr Marius Cautun, a postdoctoral fellow in Durham University's Institute for Computational Cosmology, said: "While two billion years is an extremely long time compared to a human lifetime, it is a very short time on cosmic timescales.

"The destruction of the Large Magellanic Cloud, as it is devoured by the Milky Way, will wreak havoc with our galaxy, waking up the black hole that lives at its centre and turning our galaxy into an 'active galactic nucleus' or quasar.

"This phenomenon will generate powerful jets of high energy radiation emanating from just outside the black hole. While this will not affect our Solar System, there is a small chance that we might not escape unscathed from the collision between the two galaxies which could knock us out of the Milky Way and into interstellar space."

The collision between the Large Magellanic Cloud and the Milky Way could be spectacular, the researchers say.

Co-author Professor Carlos Frenk, Director of the Institute for Computational Cosmology, Durham University, said: "Beautiful as it is, our Universe is constantly evolving, often through violent events like the forthcoming collision with the Large Magellanic Cloud.

"Barring any disasters, like a major disturbance to the Solar System, our descendants, if any, are in for a treat: a spectacular display of cosmic fireworks as the newly awakened supermassive black hole at the centre of our galaxy reacts by emitting jets of extremely bright energetic radiation."

According to the researchers, the merger of the two galaxies could be long overdue in cosmic terms.

Dr Alis Deason, of Durham University's Institute for Computational Cosmology, said: "We think that up to now our galaxy has had only a few mergers with very low mass galaxies.

"This represents very slim pickings when compared to nearby galaxies of the same size as the Milky Way. For example, our nearest neighbour, the Andromeda galaxy, devoured galaxies weighing nearly 30 times more than those consumed by the Milky Way.

"Therefore, the collision with the Large Magellanic Cloud is long overdue and it is needed to make our galaxy typical."

Although helium is a rare element on Earth, it is ubiquitous in the Universe. It is, after hydrogen, the main component of stars and gaseous giant planets. Despite its abundance, helium was only detected recently in the atmosphere of a gaseous giant by an international team including astronomers from the University of Geneva (UNIGE), Switzerland. The team, this time led by Genevan researchers, has observed in detail and for the first time how this gas escapes from the overheated atmosphere of an exoplanet, literally inflated with helium. The results are published in Science.

Helium is the second most abundant element in the Universe. Predicted since 2000 as one of the best possible tracers of the atmospheres of exoplanets, these planets orbiting around other stars than the Sun, it took astronomers 18 years to actually detect it. It was hard to spot due to the very peculiar observational signature of helium, located in the infrared, out of range for most of the instruments used previously. The discovery occurred earlier this year, thanks to Hubble Space Telescope observations, which proved difficult to interpret. Team members from UNIGE, members of the National Centre for Competence in Research PlanetS, had the idea of pointing another telescope equipped with a brand-new instrument - a spectrograph called Carmenes.

Detecting colours of planets with Carmenes

A spectrograph decomposes the light of a star into its component colours, like a rainbow. The "resolution" of a spectrograph is a measure indicating the number of colours that can be revealed. While the human eye cannot distinguish any colour beyond red without an adapted camera, the infrared eye of Hubble is capable of identifying hundreds of colours there. This proved sufficient to identify the coloured signature of helium. The instrument Carmenes, installed on the 4-metre telescope at the observatory of Calar Alto in Andalusia, Spain, is capable to identify more than 100'000 colours in the infrared!

This high spectral resolution allowed the team to observe the position and speed of helium atoms in the upper atmosphere of a gaseous Neptune-size exoplanet, 4 times larger than the Earth. Located in the Cygnus (the Swan) constellation, 124 light-years from home, HAT-P-11b is a "warm Neptune" (a decent 550°C!), twenty times closer to its star than the Earth from the Sun. "We suspected that this proximity with the star could impact the atmosphere of this exoplanet" says Romain Allart, PhD student at UNIGE and first author of the study. "The new observations are so precise that the exoplanet atmosphere is undoubtedly inflated by the stellar radiation and escapes to space", he adds.

A planet inflated with helium

These observations are supported by numerical simulation, led by Vincent Bourrier, co-author of the study and member of the European project FOUR ACES*. Thanks to the simulation, it is possible to track the trajectory of helium atoms: "helium is blown away from the day side of the planet to its night side at over 10'000 km/h", Vincent Bourrier explains. "Because it is such a light gas, it escapes easily from the attraction of the planet and forms an extended cloud all around it". This gives HAT-P-11b the shape of a helium-inflated balloon.

This result opens a new window to observe the extreme atmospheric conditions prevailing in the hottest exoplanets. The Carmenes observations demonstrate that such studies, long thought feasible only from space, can be achieved with greater precision by ground-based telescopes equipped with the right kind of instruments. "These are exciting times for the search of atmospheric signatures in exoplanets", says Christophe Lovis, senior lecturer at UNIGE and co-author of the study. In fact, UNIGE astronomers are also heavily involved in the design and exploitation of two new high-resolution infrared spectrographs, similar to Carmenes. One of them, called SPIRou, has just started an observational campaign from Hawaii, while the UNIGE Department of astronomy houses the first tests of the Near Infrared Planet Searcher (NIRPS), which will be installed in Chile at the end of 2019. "This result will enhance the interest of the scientific community for these instruments. Their number and their geographical distribution will allow us to cover the entire sky, in search for evaporating exoplanets", concludes Lovis.

Scientists at The University of Texas at Austin's Marine Science Institute have discovered nearly two dozen new types of microbes, many of which use hydrocarbons such as methane and butane as energy sources to survive and grow--meaning the newly identified bacteria might be helping to limit the concentrations of greenhouse gases in the atmosphere and might one day be useful for cleaning up oil spills.

In a paper published in Nature Communications this week, researchers documented extensive diversity in the microbial communities living in the extremely hot, deep-sea sediments located in the Guaymas Basin in the Gulf of California. The team uncovered new microbial species that are so genetically different from those that have been previously studied that they represent new branches in the tree of life. Many of these same species possess keen pollutant-eating powers, like other, previously identified microbes in the ocean and soil.

"This shows the deep oceans contain expansive unexplored biodiversity, and microscopic organisms there are capable of degrading oil and other harmful chemicals," said assistant professor of marine science Brett Baker, the paper's primary investigator. "Beneath the ocean floor huge reservoirs of hydrocarbon gases--including methane, propane, butane and others--exist now, and these microbes prevent greenhouse gases from being released into the atmosphere."

The new study, representing the largest-ever genomic sampling of Guaymas Basin sediments, was co-authored by former UT postdoctoral researcher Nina Dombrowski and University of North Carolina professor Andreas P. Teske.

The researchers' analysis of sediment from 2,000 meters below the surface, where volcanic activity raises temperatures to around 200 degrees Celsius, recovered 551 genomes, 22 of which represented new entries in the tree of life. According to Baker, these new species were genetically different enough to represent new branches in the tree of life, and some were different enough to represent entirely new phyla.

"The tree of life is something that people have been trying to understand since Darwin came up with the concept over 150 years ago, and it's still this moving target at the moment," said Baker, who earlier was part of a team that mapped the most comprehensive genomic tree of life to date. "Trying to map the tree is really kind of crucial to understanding all aspects of biology. With DNA sequencing and the computer approaches that we use, we're getting closer, and things are expanding quickly."

Only about 0.1 percent of the world's microbes can be cultured, which means there are thousands, maybe even millions, of microbes yet to be discovered.

Baker's team investigates interactions between microbial communities and the nutrients available to them in the environment by taking samples of sediment and microbes in nature, and then extracting DNA from the samples. The researchers sequence the DNA to piece together individual genomes, the sets of genes in each organism, and infer from the data how microbes consume different nutrients.

"For this, we try to look for organisms that have been studied before and look for similarities and differences," said Dombrowski, who is now at the Royal Netherlands Institute for Sea Research. "This might initially sound easy, but really is not, since often more than half of the genes we find are so far uncharacterized and unknown."

The samples were collected using the Alvin submersible, the same sub that found the Titanic, because the microbes live in extreme environments. Teske, who collaborated with Baker and Dombrowski, has driven sample collection at Guaymas Basin for several years, working with scientists across the world who are using different approaches to study life there.

This month, Baker is part of a team on the Alvin sampling in areas of the basin that previously have never been studied.

"We think that this is probably just the tip of the iceberg in terms of diversity in the Guaymas Basin," Baker said. "So, we're doing a lot more DNA sequencing to try to get a handle on how much more there is. This paper is really just our first hint at what these things are and what they are doing."