NASA's Roman Mission could snap first image of a Jupiter-like world

NASA's Nancy Grace Roman Space Telescope, now under construction, will test new technologies for space-based planet hunting. The mission aims to photograph worlds and dusty disks around nearby stars with detail up to a thousand times better than possible with other observatories.

Roman will use its Coronagraph Instrument -- a system of masks, prisms, detectors, and even self-flexing mirrors built to block out the glare from distant stars and reveal the planets in orbit around them -- to demonstrate that direct imaging technologies can perform even better in space than they have with ground-based telescopes.

"We will be able to image worlds in visible light using the Roman Coronagraph," said Rob Zellem, an astronomer at NASA's Jet Propulsion Laboratory (JPL) in Southern California who is co-leading the observation calibration plan for the instrument. JPL is building Roman's Coronagraph Instrument. "Doing so from space will help us see smaller, older, and colder planets than direct imaging usually reveals, bringing us a giant leap closer to imaging planets like Earth."

A home far away from home

Exoplanets -- planets beyond our solar system -- are so distant and dim relative to their host stars that they're practically invisible, even to powerful telescopes. That's why nearly all of the worlds discovered so far have been found indirectly through effects they have on their host stars. However, recent advancements in technology allow astronomers to actually take images of the reflected light from the planets themselves.

Analyzing the colors of planetary atmospheres helps astronomers discover what the atmospheres are made of. This, in turn, can offer clues about the processes occurring on the imaged worlds that may affect their habitability. Since living things modify their environment in ways we might be able to detect, such as by producing oxygen or methane, scientists hope this research will pave the way for future missions that could reveal signs of life.

If Roman's Coronagraph Instrument successfully completes its technology demonstration phase, its polarimetry mode will allow astronomers to image the disks around stars in polarized light, familiar to many as the reflected glare blocked by polarized sunglasses. Astronomers will use polarized images to study the dust grains that make up the disks around stars, including their sizes, shapes, and possibly mineral properties. Roman may even be able to reveal structures in the disks, such as gaps created by unseen planets. These measurements will complement existing data by probing fainter dust disks orbiting nearer to their host stars than other telescopes can see.

Bridging the gap

Current direct imaging efforts are limited to enormous, bright planets. These worlds are typically super-Jupiters that are less than 100 million years old -- so young that they glow brightly thanks to heat left over from their formation, which makes them detectable in infrared light. They also tend to be very far away from their host stars because it's easier to block the star's light and see planets in more distant orbits. The Roman Coronagraph could complement other telescopes' infrared observations by imaging young super-Jupiters in visible light for the first time, according to a study by a team of scientists.

But astronomers would also like to directly image planets that are similar to our own one day -- rocky, Earth-sized planets orbiting Sun-like stars within their habitable zones, the range of orbital distances where temperatures allow liquid water to exist on a planet's surface. To do so, astronomers need to be able to see smaller, cooler, dimmer planets orbiting much closer to their host stars than current telescopes can. By photographing worlds in visible light, Roman will be able to image mature planets spanning ages up to several billion years -- something that has never been done before.

"To image Earth-like planets, we'll need 10,000 times better performance than today's instruments provide," said Vanessa Bailey, an astronomer at JPL and the instrument technologist for the Roman Coronagraph. "The Coronagraph Instrument will perform several hundred times better than current instruments, so we will be able to see Jupiter-like planets that are more than 100 million times fainter than their host stars."

A team of scientists recently simulated a promising target for Roman to image, called Upsilon Andromedae d. "This gas giant exoplanet is slightly larger than Jupiter, orbits within a Sun-like star's habitable zone, and is relatively close to Earth -- just 44 light-years away," said Prabal Saxena, an assistant research scientist at the University of Maryland, College Park and NASA's Goddard Space Flight Center in Greenbelt, Maryland, and the lead author of a paper describing the results. "What's really exciting is that Roman may be able to help us explore hazes and clouds in Upsilon Andromedae d's atmosphere and may even be able to act as a planetary thermometer by putting constraints on the planet's internal temperature!"

Opening a new frontier

The Coronagraph Instrument will contain several state-of-the-art components that have never flown aboard a space-based observatory before. For example, it will use specially designed coronagraph masks to block the glare from host stars but allow the light from dimmer, orbiting planets to filter through. These masks have innovative, complex shapes that block starlight more effectively than traditional masks.

The Roman Coronagraph will also be equipped with deformable mirrors, which help counteract small imperfections that reduce image quality. These special mirrors will measure and subtract starlight in real time, and technicians on the ground can also send commands to the spacecraft to adjust them. This will help counteract effects like temperature changes, which can slightly alter the shape of the optics.

Using this technology, Roman will observe planets so faint that special detectors will count individual photons of light as they arrive, seconds or even minutes apart. No other observatory has done this kind of imaging in visible light before, providing a vital step toward discovering habitable planets and possibly learning whether we are alone in the universe.

Read more at Science Daily

Number of wildfires to rise by 50 percent by 2100 and governments are not prepared, UN experts warn

Climate change and land-use change are projected to make wildfires more frequent and intense, with a global increase of extreme fires of up to 14 per cent by 2030, 30 per cent by the end of 2050 and 50 per cent by the end of the century, according to a new report by the UN Environment Programme (UNEP) and GRID-Arendal.

The paper calls for a radical change in government spending on wildfires, shifting their investments from reaction and response to prevention and preparedness.

The report, Spreading like Wildfire: The Rising Threat of Extraordinary Landscape Fires, finds an elevated risk even for the Arctic and other regions previously unaffected by wildfires. The report is released before representatives of 193 nations convene in Nairobi for the resumed 5th session of the UN Environment Assembly (UNEA-5.2), between 28 February and 2 March, 2022.

The publication calls on governments to adopt a new 'Fire Ready Formula,' with two-thirds of spending devoted to planning, prevention, preparedness, and recovery, with one third left for response. Currently, direct responses to wildfires typically receive over half of related expenditures, while planning and prevention receive less than one per cent.

To prevent fires, authors call for a combination of data and science-based monitoring systems with indigenous knowledge and for a stronger regional and international cooperation.

Current government responses to wildfires are often putting money in the wrong place. Those emergency service workers and firefighters on the frontlines who are risking their lives to fight forest wildfires need to be supported. We have to minimize the risk of extreme wildfires by being better prepared: invest more in fire risk reduction, work with local communities, and strengthen global commitment to fight climate change" said Inger Andersen, UNEP Executive Director.

Wildfires disproportionately affect the world's poorest nations. With an impact that extends for days, weeks and even years after the flames subside, they impede progress towards the UN Sustainable Development Goals and deepen social inequalities:
 

• People's health is directly affected by inhaling wildfire smoke, causing respiratory and cardiovascular impacts and increased health effects for the most vulnerable;
• The economic costs of rebuilding after areas are struck by wildfires can be beyond the means of low-income countries;
• Watersheds are degraded by wildfires' pollutants; they also can lead to soil erosion causing more problems for waterways;
• Wastes left behind are often highly contaminated and require appropriate disposal.

Wildfires and climate change are mutually exacerbating. Wildfires are made worse by climate change through increased drought, high air temperatures, low relative humidity, lightning, and strong winds resulting in hotter, drier, and longer fire seasons. At the same time, climate change is made worse by wildfires, mostly by ravaging sensitive and carbon-rich ecosystems like peatlands and rainforests. This turns landscapes into tinderboxes, making it harder to halt rising temperatures.

Wildlife and its natural habitats are rarely spared from wildfires, pushing some animal and plant species closer to extinction. A recent example is the Australian 2020 bushfires, which are estimated to have wiped out billions of domesticated and wild animals.

There is a critical need to better understand the behaviour of wildfires. Achieving and sustaining adaptive land and fire management requires a combination of policies, a legal framework and incentives that encourage appropriate land and fire use.

The restoration of ecosystems is an important avenue to mitigate the risk of wildfires before they occur and to build back better in their aftermath. Wetlands restoration and the reintroduction of species such as beavers, peatlands restoration, building at a distance from vegetation and preserving open space buffers are some examples of the essential investments into prevention, preparedness and recovery.

The report concludes with a call for stronger international standards for the safety and health of firefighters and for minimising the risks that they face before, during and after operations. This includes raising awareness of the risks of smoke inhalation, minimising the potential for life-threatening entrapments, and providing firefighters with access to adequate hydration, nutrition, rest, and recovery between shifts.

Read more at Science Daily

Death spiral: A black hole spins on its side

Researchers from the University of Turku, Finland, found that the axis of rotation of a black hole in a binary system is tilted more than 40 degrees relative to the axis of stellar orbit. The finding challenges current theoretical models of black hole formation.

The observation by the researchers from Tuorla Observatory in Finland is the first reliable measurement that shows a large difference between the axis of rotation of a black hole and the axis of a binary system orbit. The difference between the axes measured by the researchers in a binary star system called MAXI J1820+070 was more than 40 degrees.

Often for the space systems with smaller objects orbiting around the central massive body, the own rotation axis of this body is to a high degree aligned with the rotation axis of its satellites. This is true also for our solar system: the planets orbit around the Sun in a plane, which roughly coincides with the equatorial plane of the Sun. The inclination of the Sun rotation axis with respect to orbital axis of the Earth is only seven degrees.

"The expectation of alignment, to a large degree, does not hold for the bizarre objects such as black hole X-ray binaries. The black holes in these systems were formed as a result of a cosmic cataclysm -- the collapse of a massive star. Now we see the black hole dragging matter from the nearby, lighter companion star orbiting around it. We see bright optical and X-ray radiation as the last sigh of the infalling material, and also radio emission from the relativistic jets expelled from the system," says Juri Poutanen, Professor of Astronomy at the University of Turku and the lead author of the publication.

By following these jets, the researchers were able to determine the direction of the axis of rotation of the black hole very accurately. As the amount of gas falling from the companion star to the black hole later began to decrease, the system dimmed, and much of the light in the system came from the companion star. In this way, the researchers were able to measure the orbit inclination using spectroscopic techniques, and it happened to nearly coincide with the inclination of the ejections.

"To determine the 3D orientation of the orbit, one additionally needs to know the position angle of the system on the sky, meaning how the system is turned with respect to the direction to the North on the sky. This was measured using polarimetric techniques," says Juri Poutanen.

The results published in the Science magazine open interesting prospects towards studies of black hole formation and evolution of such systems, as such extreme misalignment is hard to get in many black hole formation and binary evolution scenarios.

"The difference of more than 40 degrees between the orbital axis and the black hole spin was completely unexpected. Scientists have often assumed this difference to be very small when they have modeled the behavior of matter in a curved time space around a black hole. The current models are already really complex, and now the new findings force us to add a new dimension to them," Poutanen states.

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A security technique to fool would-be cyber attackers

Multiple programs running on the same computer may not be able to directly access each other's hidden information, but because they share the same memory hardware, their secrets could be stolen by a malicious program through a "memory timing side-channel attack."

This malicious program notices delays when it tries to access a computer's memory, because the hardware is shared among all programs using the machine. It can then interpret those delays to obtain another program's secrets, like a password or cryptographic key.

One way to prevent these types of attacks is to allow only one program to use the memory controller at a time, but this dramatically slows down computation. Instead, a team of MIT researchers has devised a new approach that allows memory sharing to continue while providing strong security against this type of side-channel attack. Their method is able to speed up programs by 12 percent when compared to state-of-the-art security schemes.

In addition to providing better security while enabling faster computation, the technique could be applied to a range of different side-channel attacks that target shared computing resources, the researchers say.

"Nowadays, it is very common to share a computer with others, especially if you are do computation in the cloud or even on your own mobile device. A lot of this resource sharing is happening. Through these shared resources, an attacker can seek out even very fine-grained information," says senior author Mengjia Yan, the Homer A. Burnell Career Development Assistant Professor of Electrical Engineering and Computer Science (EECS) and a member of the Computer Science and Artificial Intelligence Laboratory (CSAIL).

The co-lead authors are CSAIL graduate students Peter Deutsch and Yuheng Yang. Additional co-authors include Joel Emer, a professor of the practice in EECS, and CSAIL graduate students Thomas Bourgeat and Jules Drean. The research will be presented at the International Conference on Architectural Support for Programming Languages and Operating Systems.

Committed to memory

One can think about a computer's memory as a library, and the memory controller as the library door. A program needs to go to the library to retrieve some stored information, so that program opens the library door very briefly to go inside.

There are several ways a malicious program can exploit shared memory to access secret information. This work focuses on a contention attack, in which an attacker needs to determine the exact instant when the victim program is going through the library door. The attacker does that by trying to use the door at the same time.

"The attacker is poking at the memory controller, the library door, to say, 'is it busy now?' If they get blocked because the library door is opening already -- because the victim program is already using the memory controller -- they are going to get delayed. Noticing that delay is the information that is being leaked," says Emer.

To prevent contention attacks, the researchers developed a scheme that "shapes" a program's memory requests into a predefined pattern that is independent of when the program actually needs to use the memory controller. Before a program can access the memory controller, and before it could interfere with another program's memory request, it must go through a "request shaper" that uses a graph structure to process requests and send them to the memory controller on a fixed schedule. This type of graph is known as a directed acyclic graph (DAG), and the team's security scheme is called DAGguise.

Fooling an attacker

Using that rigid schedule, sometimes DAGguise will delay a program's request until the next time it is permitted to access memory (according to the fixed schedule), or sometimes it will submit a fake request if the program does not need to access memory at the next schedule interval.

"Sometimes the program will have to wait an extra day to go to the library and sometimes it will go when it didn't really need to. But by doing this very structured pattern, you are able to hide from the attacker what you are actually doing. These delays and these fake requests are what ensures security," Deutsch says.

DAGguise represents a program's memory access requests as a graph, where each request is stored in a "node," and the "edges" that connect the nodes are time dependencies between requests. (Request A must be completed before request B.) The edges between the nodes -- the time between each request -- are fixed.

A program can submit a memory request to DAGguise whenever it needs to, and DAGguise will adjust the timing of that request to always ensure security. No matter how long it takes to process a memory request, the attacker can only see when the request is actually sent to the controller, which happens on a fixed schedule.

This graph structure enables the memory controller to be dynamically shared. DAGguise can adapt if there are many programs trying to use memory at once and adjust the fixed schedule accordingly, which enables a more efficient use of the shared memory hardware while still maintaining security.

A performance boost

The researchers tested DAGguise by simulating how itwould perform in an actual implementation. They constantly sent signals to the memory controller, which is how an attacker would try to determine another program's memory access patterns. They formally verified that, with any possible attempt, no private data were leaked.

Then they used a simulated computer to see how their system could improve performance, compared to other security approaches.

"When you add these security features, you are going to slow down compared to a normal execution. You are going to pay for this in performance," Deutsch explains.

While their method was slower than a baseline insecure implementation, when compared to other security schemes, DAGguise led to a 12 percent increase in performance.

Read more at Science Daily

ADHD linked to hoarding behavior

New research has found that people with Attention Deficit/Hyperactivity Disorder (ADHD) are significantly more likely to also exhibit hoarding behaviours, which can have a serious impact on their quality of life.

The study, published in the Journal of Psychiatric Research and funded by theBritish Academy and the Leverhulme Trust, found that almost one in five people with ADHD exhibited clinically significant levels of hoarding, indicating there could be a hidden population of adults struggling with hoarding and its consequences.

Hoarding Disorder is a recognised condition that involves excessive accumulation, difficulties discarding and excessive clutter. The disorder can lead to distress or difficulties in everyday life and can contribute to depression and anxiety.

Previous research into Hoarding Disorder has mainly focused on older females who self-identify as hoarders and have sought help later in life. This new study, led by Dr Sharon Morein of Anglia Ruskin University (ARU), recruited 88 participants from an adult ADHD clinic run by the Cambridge and Peterborough NHS Foundation Trust.

The study found that 19% of this ADHD group displayed clinically significant hoarding symptoms, were on average in their 30s, and there was an equal gender split. Amongst the remaining 81%, the researchers found greater hoarding severity, but not to a degree that significantly impaired their lives, compared to the study's control group.

The researchers asked the same questions, about ADHD symptoms and impulsivity, levels of hoarding and clutter, obsessive compulsive severity, perfectionism, depression and anxiety, and everyday function, on a closely-matched group of 90 adults from the general population, without an ADHD diagnosis, and found only 2% of this control group exhibited clinically significant hoarding symptoms.

They then replicated this with a larger online sample of 220 UK adults to see if similar patterns were found, and similarly only 3% of this group exhibited symptoms.

Dr Morein, Associate Professor in Psychology at Anglia Ruskin University (ARU), said: "Hoarding Disorder is much more than simply collecting too many possessions. People with diagnosed Hoarding Disorder have filled their living areas with so many items and clutter that it impacts their day-to-day functioning leading to a poorer quality of life, anxiety, and depression.

"Overall, we found that people who had been diagnosed with ADHD had a higher likelihood of also having hoarding symptoms. This is important because it demonstrates that hoarding doesn't just affect people later in life, who are typically the focus of much of the research so far into Hoarding Disorder.

"Our findings also indicate that Hoarding Disorder should be routinely assessed in individuals with ADHD, as they do not typically disclose associated difficulties despite these potentially impairing their everyday lives. Likewise, it is possible that many people who are currently being treated for Hoarding Disorder might also have undiagnosed ADHD.

Read more at Science Daily

Largest ever human family tree: 27 million ancestors

Researchers from the University of Oxford's Big Data Institute have taken a major step towards mapping the entirety of genetic relationships among humans: a single genealogy that traces the ancestry of all of us. The study has been published today in Science.

The past two decades have seen extraordinary advancements in human genetic research, generating genomic data for hundreds of thousands of individuals, including from thousands of prehistoric people. This raises the exciting possibility of tracing the origins of human genetic diversity to produce a complete map of how individuals across the world are related to each other.

Until now, the main challenges to this vision were working out a way to combine genome sequences from many different databases and developing algorithms to handle data of this size. However, a new method published today by researchers from the University of Oxford's Big Data Institute can easily combine data from multiple sources and scale to accommodate millions of genome sequences.

Dr Yan Wong, an evolutionary geneticist at the Big Data Institute, and one of the principal authors, explained: "We have basically built a huge family tree, a genealogy for all of humanity that models as exactly as we can the history that generated all the genetic variation we find in humans today. This genealogy allows us to see how every person's genetic sequence relates to every other, along all the points of the genome."

Since individual genomic regions are only inherited from one parent, either the mother or the father, the ancestry of each point on the genome can be thought of as a tree. The set of trees, known as a "tree sequence" or "ancestral recombination graph," links genetic regions back through time to ancestors where the genetic variation first appeared.

Lead author Dr Anthony Wilder Wohns, who undertook the research as part of his PhD at the Big Data Institute and is now a postdoctoral researcher at the Broad Institute of MIT and Harvard, said: "Essentially, we are reconstructing the genomes of our ancestors and using them to form a vast network of relationships. We can then estimate when and where these ancestors lived. The power of our approach is that it makes very few assumptions about the underlying data and can also include both modern and ancient DNA samples."

The study integrated data on modern and ancient human genomes from eight different databases and included a total of 3,609 individual genome sequences from 215 populations. The ancient genomes included samples found across the world with ages ranging from 1,000s to over 100,000 years. The algorithms predicted where common ancestors must be present in the evolutionary trees to explain the patterns of genetic variation. The resulting network contained almost 27 million ancestors.

After adding location data on these sample genomes, the authors used the network to estimate where the predicted common ancestors had lived. The results successfully recaptured key events in human evolutionary history, including the migration out of Africa.

Although the genealogical map is already an extremely rich resource, the research team plans to make it even more comprehensive by continuing to incorporate genetic data as it becomes available. Because tree sequences store data in a highly efficient way, the dataset could easily accommodate millions of additional genomes.

Dr Wong said: "This study is laying the groundwork for the next generation of DNA sequencing. As the quality of genome sequences from modern and ancient DNA samples improves, the trees will become even more accurate and we will eventually be able to generate a single, unified map that explains the descent of all the human genetic variation we see today."

Read more at Science Daily

Microscopic view on asteroid collisions could help us understand planet formation

A new way of dating collisions between asteroids and planetary bodies throughout our Solar System's history could help scientists reconstruct how and when planets were born.

A team of researchers, led by the University of Cambridge, combined dating and microscopic analysis of the Chelyabinsk meteorite -- which fell to Earth and hit the headlines in 2013 -- to get more accurate constraints on the timing of ancient impact events.

Their study, published in Communications Earth & Environment, looked at how minerals within the meteorite were damaged by different impacts over time, meaning they could identify the biggest and oldest events that may have been involved in planetary formation.

"Meteorite impact ages are often controversial: our work shows that we need to draw on multiple lines of evidence to be more certain about impact histories -- almost like investigating an ancient crime scene," said Craig Walton, who led the research and is based at Cambridge's Department of Earth Sciences.

Early in our Solar System's history, planets including the Earth formed from massive collisions between asteroids and even bigger bodies, called proto-planets.

"Evidence of these impacts is so old that it has been lost on the planets -- Earth in particular has a short memory because surface rocks are continually recycled by plate tectonics," said co-author Dr Oli Shorttle, who is based jointly at Cambridge's Department of Earth Sciences and Institute of Astronomy.

Asteroids, and their fragments that fall to Earth as meteorites, are in contrast inert, cold and much older -- making them faithful timekeepers of collisions.

The new research, which was a collaboration with researchers from the Chinese Academy of Sciences and the Open University, recorded how phosphate minerals inside the Chelyabinsk meteorite were shattered to varying degrees in order to piece together a collision history.

Their aim was to corroborate uranium-lead dating of the meteorite, which looks at the time elapsed for one isotope to decay to another.

"The phosphates in most primitive meteorites are fantastic targets for dating the shock events experienced by the meteorites on their parent bodies," said Dr Sen Hu, who carried out the uranium-lead dating at Beijing's Institute of Geology and Geophysics, Chinese Academy of Sciences.

Previous dating of this meteorite has revealed two impact ages, one older, roughly 4.5-billion-year-old collision and another which occurred within the last 50 million years.

But these ages aren't so clear-cut. Much like a painting fading over time, successive collisions can obscure a once clear picture, leading to uncertainty among the scientific community over the age and even the number of impacts recorded.

The new study put the collisions recorded by the Chelyabinsk meteorite in time order by linking new uranium-lead ages on the meteorite to microscopic evidence for collision-induced heating seen inside their crystal structures. These microscopic clues build up in the minerals with each successive impact, meaning the collisions can be distinguished, put in time order and dated.

Their findings show that minerals containing the imprint of the oldest collision were either shattered into many smaller crystals at high temperatures or strongly deformed at high pressures.

The team also described some mineral grains in the meteorite that were fractured by a lesser impact, at lower pressures and temperatures, and which record a much more recent age of less than 50 million years. They suggest this impact probably chipped the Chelyabinsk meteorite off its host asteroid and sent it hurtling to Earth.

Taken together, this supports a two-stage collision history. "The question for us was whether these dates could be trusted, could we tie these impacts to evidence of superheating from an impact?" said Walton. "What we've shown is that the mineralogical context for dating is really important."

Scientists are particularly interested in the date of the 4.5-billion-year-old impact because this is about the time we think the Earth-Moon system came to being, probably as a result of two planetary bodies colliding.

The Chelyabinsk meteorite belongs to a group of so-called stony meteorites, all of which contain highly shattered and remelted material roughly coincident with this colossal impact.

The newly-acquired dates support previous suggestions that many asteroids experienced high energy collisions between 4.48 -- 4.44 billion years ago. "The fact that all of these asteroids record intense melting at this time might indicate Solar System re-organisation, either resulting from the Earth-Moon formation or perhaps the orbital movements of giant planets."

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Astronomers map mysterious element in space

A research team led by Lund University in Sweden has provided an important clue to the origin of the element Ytterbium in the Milky Way, by showing that the element largely originates from supernova explosions. The groundbreaking research also provides new opportunities for studying the evolution of our galaxy. The study is published in Astronomy & Astrophysics.

Ytterbium is one of four elements in the periodic table named after the Ytterby mine in the Stockholm archipelago. The element was first discovered in the black mineral gadolinite, which was first identified in the Ytterby mine in 1787.

Ytterbium is interesting because it may have two different cosmic origins. Researchers believe that one half comes from heavy stars with short lives, while the other half comes from more regular stars, much like the sun, and that they create Ytterbium in the final stages of their relatively long lives.

"By studying stars formed at different times in the Milky Way, we have been able to investigate how fast the Ytterbium content increased in the galaxy. What we have succeeded in doing is adding relatively young stars to the study," says Martin Montelius, astronomy researcher at Lund University at the time of the research, and now at the University of Groningen.

It has been speculated that Ytterbium was thrown into space by supernova explosions, stellar winds and planetary nebulae. There, it accumulated in large space clouds from which new stars formed.

By examining high-quality spectra of about 30 stars in the sun's vicinity, the researchers were able to provide important experimental support for the theory of the cosmic origin of Ytterbium. It seems that Ytterbium largely originates from supernova explosions.

"The instrument we used is a super-sensitive spectrometer that can detect infrared light in high resolution. It was used with two telescopes in the southern United States, one in Arizona and one in Texas," says Martin Montelius.

Since the Ytterbium analysis was done using infrared light, it will now be possible to study large areas of the Milky Way that lie behind impenetrable dust. Infrared light can get through the dust in the same way that red light from a sunset can get through the Earth's atmosphere.

Read more at Science Daily

New stem cell population provides a new way to study the awakening of the human genome

Researchers from the Babraham Institute have today published their latest work in the journal Cell Stem Cell describing a new subset of human embryonic stem cells that closely resemble the cells present at the genomic 'wake up call' of the 8-cell embryo stage in humans. This new stem cell model will allow researchers to map out the key genomic changes during early development, and help move towards a better understanding of the implications of genome activation errors in developmental disorders and embryo loss.

In all mammals, the early embryo undergoes a number of molecular events just after fertilisation that set the stage for the rest of development. During this key 'wake up call' the genome of the embryo takes over control of the cell's activities from the maternal genome. In humans, this happens at the 8-cell stage and is called zygotic genome activation (ZGA). Before the findings of this study, investigating the details of human ZGA could only be done in human embryos; existing human stem cell models represented the embryo only at later stages of the developmental process. In the UK, experiments using embryos are permitted but highly regulated, meaning that research into early development relied in part on alternative, non-human models.

In 2012, cells representing the genome activation stage of development were found in mouse embryonic stem cells (ESCs), allowing researchers to learn more about mammalian ZGA. Almost a decade later, the Reik lab at the Institute have found a human equivalent. The lab's discovery opens up a way to advance our knowledge of the earliest events during preimplantation development.

Dr Jasmin Taubenschmid-Stowers, lead author and Research Fellow in the Reik lab, part of the Institute's Epigenetics research programme , commented: "Studying mouse embryonic stem cells has allowed researchers to learn about the general process of genome activation, but we could learn even more about this important step in human development thanks to our discovery of a human stem cell counterpart."

In order to function, cells take copies of the genome in the form of an RNA code which is translated into proteins. The RNA code output is called the transcriptome and it can be used to identify different populations of cells. In this study, researchers used existing human data sets and information from mouse ESC studies to identify characteristic transcriptome marks that could be linked to genome activation. Using single cell techniques, they started the search for similar cells in their population of human ESCs.

The team found a subset of human ESCs with the right transcriptome marks to be a potential match for the 8-cell stage, when the major wave of genome activation occurs. They called these cells '8-cell like cells' or 8CLCs and used the published human data to further validate and confirm that these cells shared the same molecular outputs indicative of genome activation and could be pursued as a reliable model for future studies.

To further explore the extent of the similarities between their 8CLCs and 8-cell stage in human embryos, the team worked with Professor Jennifer Nichols from the Wellcome -- MRC Cambridge Stem Cell Institute. Together they were able to select and search for proteins present in both sets of cells that were indicative of ZGA. Their results showed that the ZGA-associated proteins of 8CLCs closely matched those seen in human 8-cell embryos.

As Jasmin explains: "The collaboration with Professor Nichols and her team was vital as we could identify selected proteins and really look at those in real, fixed human 8-cell stage embryo cells compared to our new stem cell counterparts. This work confirmed that our 8C-like cells matched at the protein level too, in additional to the transcriptomics data, providing validation that the 8-cell like cells matched embryo cells across multiple molecular layers."

Read more at Science Daily

The impacts from using genetic testing to track down relatives

Genetic genealogy has become a popular hobby over the past several years, thanks to direct-to-consumer (DTC) genetic testing and relative-finder services offered by some DTC genetic testing companies. In a paper published February 24 in the American Journal of Human Genetics, researchers report results from a survey that asked people who had participated in these services what effect the discovery of previously unknown relatives had on their lives.

Among the most important findings were that identifying a genetic relative appeared to be somewhat common. Additionally, those discoveries were generally experienced as neutral or positive and didn't appear to have a big impact on participants' lives. However, some participants learned things that could be considered significant and destabilizing -- such as that their biological parent wasn't who they thought. These participants were especially vulnerable to negative outcomes.

"Everyone on our team is involved in studying the ethical, legal, and social implications of DTC genetic testing, and we've been paying attention to stories in the media about individuals who've made surprising family discoveries from these tests and relative-matching services," says lead author Christi Guerrini of the Center for Medical Ethics and Health Policy at Baylor College of Medicine. "We wanted to understand if these and other kinds of discoveries are common, how they're experienced by those making the discoveries, and what people are doing as a result."

The investigators sent the survey to about one million DTC genetic testing customers and genetic genealogy database participants; more than 26,000 responded. The final sample for analysis consisted of 23,196 completed or substantially completed surveys. Among the reasons that respondents said they chose to participate in this type of testing were to learn more about their family or build their family trees; to search for a biological parent, child, or other relative; or to investigate a suspicion that they might not be genetically related to family members.

"It seems that many -- perhaps most -- are just curious about their families and interested in building out their family trees, but it's clear that quite a lot of participants are looking for someone or hoping to confirm something in particular," Guerrini says. "It might be that they're adopted and looking for a biological parent, or that they've always felt out of place in their family and want to see if there's something to that feeling. Or they might be looking for information about a branch of their family tree that's unknown to them, or to confirm a family story that's been passed down over the years."

Most respondents (82%) reported that they learned the identity of at least one genetic relative. Among this subpopulation, 10% identified a biological grandparent, 10% identified a full or half- sibling, and 7% identified a biological father. The survey asked whether the participant had chosen to contact any of their newly identified relatives and, if so, the reasons for doing so. It also asked whether their discoveries resulted in any life changes, including changes in health-related behaviors.

Guerrini says that the high number of people overall who identified an unknown genetic relative was not unexpected, because many of those relatives could be very distant ones. But she acknowledges that the high number of participants who found close relatives could be skewed by the type of people who choose to undergo relative matching in the first place. "Unfortunately, we can't answer that question with our data, but I'm very interested in trying to do so in future research," she says.

She adds that although these experiences appear to be interesting and enjoyable to a large number of people, it's clear that some who are participating in these services have experienced negative outcomes. "In future research, we'd like to better understand those outcomes and what resources could be helpful in managing them," she says.

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Colossal black holes locked in dance at heart of galaxy

Locked in an epic cosmic waltz 9 billion light years away, two supermassive black holes appear to be orbiting around each other every two years. The two giant bodies each have masses that are hundreds of millions of times larger than that of our sun, and the objects are separated by a distance roughly 50 times that which separates our sun and Pluto. When the pair merge in roughly 10,000 years, the titanic collision is expected to shake space and time itself, sending gravitational waves across the universe.

A Caltech-led team of astronomers has discovered evidence for this scenario taking place within a fiercely energetic object known as a quasar. Quasars are active cores of galaxies in which a supermassive black hole is siphoning material from a disk encircling it. In some quasars, the supermassive black hole creates a jet that shoots out at near the speed of light. The quasar observed in the new study, PKS 2131-021, belongs to a subclass of quasars called blazars in which the jet is pointing toward the Earth. Astronomers already knew quasars could possess two orbiting supermassive black holes, but finding direct evidence for this has proved difficult.

Reporting in The Astrophysical Journal Letters, the researchers argue that PKS 2131-021 is now the second known candidate for a pair of supermassive black holes caught in the act of merging. The first candidate pair, within a quasar called OJ 287, orbit each other at greater distances, circling every nine years versus the two years it takes for the PKS 2131-021 pair to complete an orbit.

The telltale evidence came from radio observations of PKS 2131-021 that span 45 years. According to the study, a powerful jet emanating from one of the two black holes within PKS 2131-021 is shifting back and forth due to the pair's orbital motion. This causes periodic changes in the quasar's radio-light brightness. Five different observatories registered these oscillations, including Caltech's Owens Valley Radio Observatory (OVRO), the University of Michigan Radio Astronomy Observatory (UMRAO), MIT's Haystack Observatory, the National Radio Astronomy Observatory (NRAO), Metsähovi Radio Observatory in Finland, and NASA's Wide-field Infrared Survey Explorer (WISE) space satellite.

The combination of the radio data yields a nearly perfect sinusoidal light curve unlike anything observed from quasars before.

"When we realized that the peaks and troughs of the light curve detected from recent times matched the peaks and troughs observed between 1975 and 1983, we knew something very special was going on," says Sandra O'Neill, lead author of the new study and an undergraduate student at Caltech who is mentored by Tony Readhead, Robinson Professor of Astronomy, Emeritus.

Ripples in Space and Time

Most, if not all, galaxies possess monstrous black holes at their cores, including our own Milky Way galaxy. When galaxies merge, their black holes "sink" to the middle of the newly formed galaxy and eventually join together to form an even more massive black hole. As the black holes spiral toward each other, they increasingly disturb the fabric of space and time, sending out gravitational waves, which were first predicted by Albert Einstein more than 100 years ago.

The National Science Foundation's LIGO (Laser Interferometer Gravitational-Wave Observatory), which is managed jointly by Caltech and MIT, detects gravitational waves from pairs of black holes up to dozens of times the mass of our sun. However, the supermassive black holes at the centers of galaxies have millions to billions of times as much mass as our sun, and give off lower frequencies of gravitational waves than those detected by LIGO.

In the future, pulsar timing arrays -- which consist of an array of pulsing dead stars precisely monitored by radio telescopes -- should be able to detect the gravitational waves from supermassive black holes of this heft. (The upcoming Laser Interferometer Space Antenna, or LISA, mission would detect merging black holes whose masses are 1,000 to 10 million times greater than the mass of our sun.) So far, no gravitational waves have been registered from any of these heavier sources, but PKS 2131-021 provides the most promising target yet.

In the meantime, light waves are the best option to detect coalescing supermassive black holes.

The first such candidate, OJ 287, also exhibits periodic radio-light variations. These fluctuations are more irregular, and not sinusoidal, but they suggest the black holes orbit each other every nine years. The black holes within the new quasar, PKS 2131-021, orbit each other every two years and are 2,000 astronomical units apart, about 50 times the distance between our sun and Pluto, or 10 to 100 times closer than the pair in OJ 287. (An astronomical unit is the distance between Earth and the sun.)

Revealing the 45-Year Light Curve

Readhead says the discoveries unfolded like a "good detective novel," beginning in 2008 when he and colleagues began using the 40-meter telescope at OVRO to study how black holes convert material they "feed" on into relativistic jets, or jets traveling at speeds up to 99.98 percent that of light. They had been monitoring the brightness of more than 1,000 blazars for this purpose when, in 2020, they noticed a unique case.

"PKS 2131 was varying not just periodically, but sinusoidally," Readhead says. "That means that there is a pattern we can trace continuously over time." The question, he says, then became how long has this sine wave pattern been going on?

The research team then went through archival radio data to look for past peaks in the light curves that matched predictions based on the more recent OVRO observations. First, data from NRAO's Very Long Baseline Array and UMRAO revealed a peak from 2005 that matched predictions. The UMRAO data further showed there was no sinusoidal signal at all for 20 years before that time -- until as far back as 1981 when another predicted peak was observed.

"The story would have stopped there, as we didn't realize there were data on this object before 1980," Readhead says. "But then Sandra picked up this project in June of 2021. If it weren't for her, this beautiful finding would be sitting on the shelf."

O'Neill began working with Readhead and the study's second author Sebastian Kiehlmann, a postdoc at the University of Crete and former staff scientist at Caltech, as part of Caltech's Summer Undergraduate Research Fellowship (SURF) program. O'Neill began college as a chemistry major but picked up the astronomy project because she wanted to stay active during the pandemic. "I came to realize I was much more excited about this than anything else I had worked on," she says.

With the project back on the table, Readhead searched through the literature and found that the Haystack Observatory had made radio observations of PKS 2131-021 between 1975 and 1983. These data revealed another peak matching their predictions, this time occurring in 1976.

"This work shows the value of doing accurate monitoring of these sources over many years for performing discovery science," says co-author Roger Blandford, Moore Distinguished Scholar in Theoretical Astrophysics at Caltech who is currently on sabbatical from Stanford University.

Like Clockwork

Readhead compares the system of the jet moving back and forth to a ticking clock, where each cycle, or period, of the sine wave corresponds to the two-year orbit of the black holes (though the observed cycle is actually five years due to light being stretched by the expansion of the universe). This ticking was first seen in 1976 and it continued for eight years before disappearing for 20 years, likely due to changes in the fueling of the black hole. The ticking has now been back for 17 years.

"The clock kept ticking," he says, "The stability of the period over this 20-year gap strongly suggests that this blazar harbors not one supermassive black hole, but two supermassive black holes orbiting each other."

The physics underlying the sinusoidal variations were at first a mystery, but Blandford came up with a simple and elegant model to explain the sinusoidal shape of the variations.

"We knew this beautiful sine wave had to be telling us something important about the system," Readhead says. "Roger's model shows us that it is simply the orbital motion that does this. Before Roger worked it out, nobody had figured out that a binary with a relativistic jet would have a light curve that looked like this."

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Fate of the dinosaurs sealed in spring

The asteroid that killed nearly all dinosaurs struck Earth during springtime. An international team of scientists from the Vrije Universiteit (VU) Amsterdam (The Netherlands), Uppsala University (Sweden), Vrije Universiteit Brussel (Belgium) and the ESRF, the European Synchrotron (France), have determined when the meteorite crashed onto the Earth, after analysing the remains of fishes that died just after the impact. Their results are published in the journal Nature today.

Around 66 million years ago, the so-called Chicxulub meteorite crashed into the Earth, in what today is the Yucatán peninsula in Mexico, marking the demise of dinosaurs and end of the Cretaceous period. This mass extinction still puzzles scientists today, as it was one of the most selective in the history of life: all non-avian dinosaurs, pterosaurs, ammonites, and most marine reptiles disappeared, whilst mammals, birds, crocodiles, and turtles survived.

A team of scientists from the Vrije Universiteit, Uppsala University, and the ESRF have now shed light on the circumstances surrounding the diverse extinction across the different groups. The answers came from the bones of fishes that died moments after the meteorite struck.

When the meteorite impacted Earth, it rocked the continental plate and caused huge waves in water bodies, such as rivers and lakes. These moved enormous volumes of sediment that engulfed fish and buried them alive, while impact spherules (glass beads of Earth rock) rained down from the sky, less than an hour after impact. Today, the event deposit of Tanis in North Dakota (United States) preserves a fossilised ecosystem that includes paddlefishes and sturgeons, which were direct casualties of the event.

The fossil fishes were exceptionally preserved, with their bones showing almost no signs of geochemical alteration. Melanie During, researcher from Uppsala University and the VU Amsterdam and lead author of the publication, went onsite to excavate the precious specimens: "It was obvious to us that we needed to analyse these bones to get valuable information about the moment of the impact," she explains.

The team came to the ESRF, a particle accelerator that produces the world's brightest x-rays, with a partial fish specimen and representative sections of the bones and carried out high-resolution synchrotron X-ray tomography.

The ESRF is the perfect tool to research this kind of samples and the facility has developed unique expertise in palaeontology over the last two decades. "Thanks to the ESRF's data, we found that the bones registered seasonal growth, very much like trees do, growing a new layer every year on the outside of the bone," explains Sophie Sanchez of Uppsala University, and visiting scientist at the ESRF.

"The retrieved growth rings not only captured the life histories of the fishes but also recorded the latest Cretaceous seasonality and thus the season in which the catastrophic extinction occurred," states senior author Jeroen van der Lubbe of the VU in Amsterdam.

The X-ray scans also showed the distribution, shapes, and sizes of the bone cells, which are known to fluctuate with the seasons as well. "In all studied fishes, bone cell density and volumes can be traced over multiple years and they indicate whether it was spring, summer, autumn, or winter. We saw that both cell density and volumes were on the rise but had not yet peaked during the year of death, which implies that growth abruptly stopped spring" says Dennis Voeten, researcher at Uppsala University.

In parallel to synchrotron radiation studies, the team carried out carbon isotope analysis to reveal the annual feeding pattern of a fish. The availability of zooplankton, its prey of choice, oscillated seasonally and peaked in summer. This temporary increase of ingested zooplankton enriched the skeleton of the fish with the heavier 13C carbon isotope relative to the lighter 12C carbon isotope. "The carbon isotope signal across the growth record of this unfortunate paddlefish confirms that the feeding season had not yet climaxed -- death came in spring," asserts During.

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Positive parenting can reduce the risk that children develop obesity

New research from Penn State found that children with positive, early interactions with their care givers -- characterized by warmth, responsiveness, and a sitmulating home environment -- were at reduced risk of childhood obesity.

"A lot of the discussion around childhood obesity and other health risks focuses on identifying and studying the exposure to risk," said Brandi Rollins, assistant research professor of biobehavioral health. "We took a strength-based approach in our analysis. We found that a supportive family and environment early in a child's life may outweigh some of the cumulative risk factors that children can face."

The study, "Family Psychosocial Assets, Child Behavioral Regulation, and Obesity," recently appeared in the journal Pediatrics. In the article, Rollins and Lori Francis, associate professor of biobehavioral health, analyzed data from over 1,000 mother-child pairs and found that children's early exposures to family psychosocial assets -- including a quality home environment, emotional warmth from the mother, and a child's ability to self-regulate -- reduced the risk of developing childhood obesity.

Encouragingly, these factors were protective even when children faced familial risks for obesity, including poverty, maternal depression, or residence in a single-parent home.

"Research on parenting has shown that these types of family assets influence children's behavior, academic success, career, and -- not surprisingly -- health," Rollins said. "It is significant that these factors also protect against childhood obesity because the family assets we studied are not food or diet-specific at all. It is heartening to know that, by providing a loving, safe environment, we can reduce the risk that children will develop obesity."

Severe obesity

Children are deemed to have obesity when their body mass indices (BMIs) are greater than 95% of other children their age and gender. There is a great deal of variance, however, in the BMIs of children who exceed the obesity threshold. Children whose BMI is 20% higher than the obesity threshold are considered to have severe obesity.

The researchers found that children who had early-onset severe obesity did not face greater levels of family risk than children who were not obese. Children with severe obesity, however, did have fewer family assets than children who were not obese or who displayed moderate levels of obesity. More research is needed to understand which factors contribute to the development of severe obesity and which factors reduce the risk.

"Though the findings on severe obesity may seem discouraging, they offer some hope," Rollins explained. "Some risk factors, like household poverty, can be very difficult to change. Assets, on the other hand, may be easier to build. People can learn to parent responsively. It is encouraging that parenting really matters, that family matters."

What parents can do

This work is based on research in parenting and child development. Responsive parenting, one of the family assets measured in the study, involves responding to children in a timely, sensitive, and age-appropriate manner based on the child's presenting needs. Researchers in Penn State's Center for Childhood Obesity Research are also exploring how responsive parenting can reduce the risk of childhood obesity.

This study focused on childhood obesity, but the researchers said that parents may improve many outcomes for their children by learning responsive-parenting skills. Knowledge of responsive-parenting skills, however, may not lead directly to implementing those skills in the home.

"No one can read a pamphlet about cars and suddenly expect to drive," said Rollins. "Driving is a skill that requires education and practice. The same is true of responsive parenting.

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How some gut microbes awaken 'zombie' viruses in their neighbors

Some gut bacteria have a spooky superpower: they can reanimate dormant viruses lurking within other microbes.

This viral awakening unleashes full-blown infections that destroy the virus-carrying cells, Howard Hughes Medical Institute Investigator Emily Balskus's lab first published as a preprint on bioRxiv and later in the journal Nature on February 23, 2022. A cryptic molecule called colibactin can summon the killer viruses from their slumber, they found.

Microbes often generate noxious compounds to attack one another within the cramped quarters of the gut. But among these chemical weapons, colibactin appears unusual, says Balskus, a chemical biologist at Harvard University. "It doesn't directly kill the target organisms, which is what we normally think of bacterial toxins doing within microbial communities." Instead, colibactin tweaks microbial cells just so, activating latent -- and lethal -- viruses tucked away in some bacteria's genomes.

Humans have long sought out the potent compounds that microbes produce. "We know a lot about their chemical properties, we purify them in the lab, and we use them as medicine, including antibiotics," says Breck Duerkop, who studies bacterial viruses at the University of Colorado School of Medicine.

But why bacteria make these compounds and what effects they have on neighboring organisms are open-ended questions, says Duerkop, who was not involved in this research. He calls Balskus's teams new work "one step in the right direction."

Chemical dark matter

Scientists have known for years that colibactin can wreak havoc on human cells. Research by Balskus and many others has shown that the compound damages DNA, which can lead to colorectal cancer. But establishing a connection between this compound and disease proved particularly formidable.

In 2006, a French team reported that mammalian cells that encountered the gut bacteria E. coli suffered fatal damage to their DNA. The researchers linked this damage to a cluster of E. coli genes encoding machinery for building a complex molecule. Dubbed colibactin, the molecule was extraordinarily difficult to study. After many tries, researchers simply couldn't isolate it from the E. coli making it.

Colibactin is one of many ephemeral compounds that scientists suspect microbes make. Like invisible particles of dark matter in space, this "chemical dark matter" requires creative means to study. As part of her exploration of the gut's microbial chemistry, Balskus uses indirect approaches to examine these elusive molecules.

Over the past 10 years, her team has probed colibactin by studying the microbial machinery that manufactures it. She and her colleagues have pieced together colibactin's structure and determined that it damages DNA by forming errant connections within the double helix.

Building off this work, scientists elsewhere uncovered a definitive link to cancer: the molecule's distinctive fingerprints appear in genes known to drive colorectal tumor growth.

A role for viruses

Balskus's most recent colibactin study got its start with another disease: COVID-19. Like many other labs, hers had to rearrange things to reduce physical contact among researchers. As part of the reshuffling, postdoc Justin Silpe and graduate student Joel Wong ended up working near one another for the first time. Their conversations led them and Balskus to wonder how colibactin affected other microbes in a crowded gut.

Early on, they found that exposing colibactin-producing bacteria to non-producers had little effect, suggesting that, on its own, the molecule isn't particularly deadly. Silpe and Wong weren't sure if colibactin, a large, unstable molecule, could even enter bacterial cells to damage their DNA. They then wondered if a third party -- bacteria-infecting viruses -- might be involved. Hardly more than bits of genetic information, these viruses can slip into bacteria's DNA and lie quietly in wait. Then, once triggered, they cause an infection that blows up the cell like a landmine.

When the researchers grew colibactin producers alongside bacteria carrying such latent viruses, they saw the number of viral particles spike, and the growth of many virus-containing bacteria drop. That suggested the molecule sparked a surge in active, cell-killing infections. Colibactin does indeed enter bacteria and damage DNA, the team showed. That damage sounds a cellular wake-up bell that rouses the viruses.

Many microbes appeared equipped to protect themselves against colibactin. Balskus's lab identified a resistance gene encoding a protein that neutralizes the compound in a wide variety of bacteria.

Though colibactin clearly has a dangerous side, it may serve as more than just a lethal weapon, Balskus says. For example, both DNA damage and awakened viruses can also induce genetic changes, rather than death, in neighboring bacteria, potentially benefiting colibactin producers.

Balskus's team's discoveries suggest that cancer may be collateral damage caused by whatever else colibactin-producing bacteria are doing. "We always suspected that bacteria made this toxin to target other bacteria in some way," she says. "It didn't make sense from an evolutionary perspective that they acquired it to target human cells."

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A 'hot Jupiter’s' dark side is revealed in detail for first time

MIT astronomers have obtained the clearest view yet of the perpetual dark side of an exoplanet that is "tidally locked" to its star. Their observations, combined with measurements of the planet's permanent day side, provide the first detailed view of an exoplanet's global atmosphere.

"We're now moving beyond taking isolated snapshots of specific regions of exoplanet atmospheres, to study them as the 3D systems they truly are," says Thomas Mikal-Evans, who led the study as a postdoc in MIT's Kavli Institute for Astrophysics and Space Research.

The planet at the center of the new study, which appears in Nature Astronomy, is WASP-121b, a massive gas giant nearly twice the size of Jupiter. The planet is an ultrahot Jupiter and was discovered in 2015 orbiting a star about 850 light years from Earth. WASP-121b has one of the shortest orbits detected to date, circling its star in just 30 hours. It is also tidally locked, such that its star-facing "day" side is permanently roasting, while its "night" side is turned forever toward space.

"Hot Jupiters are famous for having very bright day sides, but the night side is a different beast. WASP-121b's night side is about 10 times fainter than its day side," says Tansu Daylan, a TESS postdoc at MIT who co-authored the study.

Astronomers had previously detected water vapor and studied how the atmospheric temperature changes with altitude on the planet's day side.

The new study captures a much more detailed picture. The researchers were able to map the dramatic temperature changes from the day to the night side, and to see how these temperatures change with altitude. They also tracked the presence of water through the atmosphere to show, for the first time, how water circulates between a planet's day and night sides.

While on Earth, water cycles by first evaporating, then condensing into clouds, then raining out, on WASP-121b, the water cycle is far more intense: On the day side, the atoms that make up water are ripped apart at temperatures over 3,000 Kelvin. These atoms are blown around to the night side, where colder temperatures allow hydrogen and oxygen atoms to recombine into water molecules, which then blow back to the day side, where the cycle starts again.

The team calculates that the planet's water cycle is sustained by winds that whip the atoms around the planet at speeds of up to 5 kilometers per second, or more than 11,000 miles per hour.

It also appears that water isn't alone in circulating around the planet. The astronomers found that the night side is cold enough to host exotic clouds of iron and corundum -- a mineral that makes up rubies and sapphires. These clouds, like water vapor, may whip around to the day side, where high temperatures vaporize the metals into gas form. On the way, exotic rain might be produced, such as liquid gems from the corundum clouds.

"With this observation, we're really getting a global view of an exoplanet's meteorology," Mikal-Evans says.

The study's co-authors include collaborators from MIT, Johns Hopkins University, Caltech, and other institutions.

Day and night

The team observed WASP-121b using a spectroscopic camera aboard NASA's Hubble Space Telescope. The instrument observes the light from a planet and its star, and breaks that light down into its constituent wavelengths, the intensities of which give astronomers clues to an atmosphere's temperature and composition.

Through spectroscopic studies, scientists have observed atmospheric details on the day sides of many exoplanets. But doing the same for the night side is far trickier, as it requires watching for tiny changes in the planet's entire spectrum as it circles its star.

For the new study, the team observed WASP-121b throughout two full orbits -- one in 2018, and the other in 2019. For both observations, the researchers looked through the light data for a specific line, or spectral feature, that indicated the presence of water vapor.

"We saw this water feature and mapped how it changed at different parts of the planet's orbit," Mikal-Evans says. "That encodes information about what the temperature of the planet's atmosphere is doing as a function of altitude."

The changing water feature helped the team map the temperature profile of both the day and night side. They found the day side ranges from 2,500 Kelvin at its deepest observable layer, to 3,500 Kelvin in its topmost layers. The night side ranged from 1,800 Kelvin at its deepest layer, to 1,500 Kelvin in its upper atmosphere. Interestingly, temperature profiles appeared to flip-flop, rising with altitude on the day side -- a "thermal inversion," in meteorological terms -- and dropping with altitude on the night side.

The researchers then passed the temperature maps through various models to identify chemicals that are likely to exist in the planet's atmosphere, given specific altitudes and temperatures. This modeling revealed the potential for metal clouds, such as iron, corundum, and titanium on the night side.

From their temperature mapping, the team also observed that the planet's hottest region is shifted to the east of the "substellar" region directly below the star. They deduced that this shift is due to extreme winds.

"The gas gets heated up at the substellar point but is getting blown eastward before it can reradiate to space," Mikal-Evans explains.

From the size of the shift, the team estimates that the wind speeds clock in at around 5 kilometers per second.

"These winds are much faster than our jet stream, and can probably move clouds across the entire planet in about 20 hours," says Daylan, who led previous work on the planet using NASA's MIT-led mission, TESS.

The astronomers have reserved time on the James Webb Space Telescope to observe WASP-121b later this year, and hope to map changes in not just water vapor but also carbon monoxide, which scientists suspect should reside in the atmosphere.

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Balkanatolia: The forgotten continent that sheds light on the evolution of mammals

A team of French, American and Turkish palaeontologists and geologists led by CNRS researchers1 has discovered the existence of a forgotten continent they have dubbed Balkanatolia, which today covers the present-day Balkans and Anatolia. Formerly inhabited by a highly specific fauna, they believe that it enabled mammals from Asia to colonise Europe 34 million years ago. Their findings are published in the March 2022 volume of Earth Science Reviews.

For millions of years during the Eocene Epoch (55 to 34 million years ago), Western Europe and Eastern Asia formed two distinct land masses with very different mammalian faunas: European forests were home to endemic fauna such as Palaeotheres (an extinct group distantly related to present-day horses, but more like today's tapirs), whereas Asia was populated by a more diverse fauna including the mammal families found today on both continents.

We know that, around 34 million years ago, Western Europe was colonised by Asian species, leading to a major renewal of vertebrate fauna and the extinction of its endemic mammals, a sudden event called the 'Grande Coupure'. Surprisingly, fossils found in the Balkans point to the presence of Asian mammals in southern Europe long before the Grande Coupure, suggesting earlier colonisation.

Now, a team led by CNRS researchers has come up with an explanation for this paradox. To do this, they reviewed earlier palaeontological discoveries, some of which date back to the 19th century, sometimes reassessing their dating in the light of current geological data. The review revealed that, for much of the Eocene, the region corresponding to the present-day Balkans and Anatolia was home to a terrestrial fauna that was homogeneous, but distinct from those of Europe and eastern Asia. This exotic fauna included, for example, marsupials of South American affinity and Embrithopoda (large herbivorous mammals resembling hippopotamuses) formerly found in Africa. The region must therefore have made up a single land mass, separated from the neighbouring continents.

The team also discovered a new fossil deposit in Turkey (Büyükteflek) dating from 38 to 35 million years ago, which yielded mammals whose affinity was clearly Asian, and are the earliest discovered in Anatolia until now. They found jaw fragments belonging to Brontotheres, animals resembling large rhinoceroses that died out at the end of the Eocene.

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Sonic advance: How sound waves could help regrow bones

Researchers have used sound waves to turn stem cells into bone cells, in a tissue engineering advance that could one day help patients regrow bone lost to cancer or degenerative disease.

The innovative stem cell treatment from researchers at RMIT University in Melbourne, Australia, offers a smart way forward for overcoming some of the field's biggest challenges, through the precision power of high-frequency sound waves.

Tissue engineering is an emerging field that aims to rebuild bone and muscle by harnessing the human body's natural ability to heal itself.

A key challenge in regrowing bone is the need for large amounts of bone cells that will thrive and flourish once implanted in the target area.

To date, experimental processes to change adult stem cells into bone cells have used complicated and expensive equipment and have struggled with mass production, making widespread clinical application unrealistic.

Additionally, the few clinical trials attempting to regrow bone have largely used stem cells extracted from a patient's bone marrow -- a highly painful procedure.

In a new study published in the journal Small, the RMIT research team showed stem cells treated with high-frequency sound waves turned into bone cells quickly and efficiently.

Importantly, the treatment was effective on multiple types of cells including fat-derived stem cells, which are far less painful to extract from a patient.

Fast and simple

Co-lead researcher Dr Amy Gelmi said the new approach was faster and simpler than other methods.

"The sound waves cut the treatment time usually required to get stem cells to begin to turn into bone cells by several days," said Gelmi, a Vice-Chancellor's Research Fellow at RMIT.

"This method also doesn't require any special 'bone-inducing' drugs and it's very easy to apply to the stem cells.

"Our study found this new approach has strong potential to be used for treating the stem cells, before we either coat them onto an implant or inject them directly into the body for tissue engineering."

The high-frequency sound waves used in the stem cell treatment were generated on a low-cost microchip device developed by RMIT.

Co-lead researcher Distinguished Professor Leslie Yeo and his team have spent over a decade researching the interaction of sound waves at frequencies above 10 MHz with different materials.

The sound wave-generating device they developed can be used to precisely manipulate cells, fluids or materials.

"We can use the sound waves to apply just the right amount of pressure in the right places to the stem cells, to trigger the change process," Yeo said.

"Our device is cheap and simple to use, so could easily be upscaled for treating large numbers of cells simultaneously -- vital for effective tissue engineering."

The next stage in the research is investigating methods to upscale the platform, working towards the development of practical bioreactors to drive efficient stem cell differentiation.

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Genetic mutation may identify women with difficulty producing breast milk

Leading health care organizations recommend exclusive breastfeeding for six months after birth, yet some mothers report stopping due to a perceived lack of milk supply. Penn State College of Medicine researchers found in a recent study that women who stopped breastfeeding because they believed they had inadequate milk supply -- a condition called perceived inadequate milk supply (PIMS) -- are more likely to have a specific mutation in a gene found in mammary tissue. These women were also more likely to have babies who gained less weight. The researchers said that screening for this mutation, when combined with maternal characteristics like age and body mass index, could be useful in identifying mothers at risk for stopping breastfeeding prematurely due to a perceived lack of milk supply.

"The World Health Organization, the American Academy of Pediatrics and the American College of Obstetricians and Gynecologists recommend exclusive breastfeeding for at least six months because it provides developing infants with optimum nutrition and is associated with improved health outcomes," said Dr. Steven Hicks, lead researcher and pediatrician at Penn State Health Children's Hospital. "While 83% of women initiate breastfeeding, only a reported 57% continue to six months. Socioeconomic and environmental factors may contribute to early cessation, but milk supply is also an often-cited reason. Identifying women who are more likely to have low milk supply could help get them resources to continue breastfeeding such as lactation consultation services."

Previous research has linked maternal genetics with nutrients in breast milk, but few studies have explored how genetics may relate to supply. The researchers studied 18 genes highly expressed in mammary, or milk-producing, tissue in women. They looked for mutations in those genes to see whether mutations were associated with mothers' perceived milk supply.

The study team followed 88 women between 19 and 42 years old for the first year of their baby's life. The mothers completed surveys about their infant's feeding habits at one, four, six and twelve months of age that asked questions about perceived milk supply, whether women supplemented their child's diet with formula and reasons why they did so. Decreased or low milk production, signs of allergies from breastfeeding and other personal reasons such as work, day care or time constraints were included as possible reasons for why women began to supplement with formula. Mothers also provided a DNA sample by having saliva collected.

Using responses from the surveys, the researchers classified the mothers as having either PIMS or perceived adequate milk supply (PAMS). They found that the 45 mothers with PIMS were more likely to breastfeed for shorter periods, report lower milk supply and have infants who were not gaining adequate weight.

The researchers analyzed the mothers' DNA samples and looked for mutations among 18 genes that are involved in the secretion of breast milk. Although modifications in 10 of the genes studied were found among some women, the team found that only one, a variant in the milk fat globule EGF and factor V/VIII domain containing gene (MFGE8), occurred more frequently in women with PIMS. Those without the mutation were more likely to have adequate milk supply and report a longer duration of breastfeeding.

Using statistical modeling, the researchers found that maternal characteristics like age, previous breastfeeding duration and body mass index alone could not differentiate between mothers with PIMS and PAMS. However, when adding in MFGE8 mutation status into the model, it strongly predicted which women reported adequate or inadequate milk supplies. The researchers published their results in the journal Breastfeeding Medicine.

"Identifying risk of PIMS at the outset of breastfeeding could provide opportunities for early, targeted interventions such as guidance from a trained lactation support professional," Hicks said. He noted that current assessment of PIMS is guided by subjective reports and that counseling may help identify foods and medications that help or hinder milk production.

Hicks said that the study's findings will need to be validated in a larger study that includes more mothers. He also said that more research is needed to uncover the biological processes that determine how this particular gene affects milk supply in moms in order to better understand its association with PIMS status.

"Moms with this mutation still produce milk, even if it may be less than women without the mutation, but challenges like poor diet, hydration or sleep could be enough to hinder the supply that they do have," Hicks said. "Screening for this variant and combining that with maternal reports and characteristics could help identify moms and babies that may need additional support."

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Astronomers discover widest separation of brown dwarf pair to date

A team of astronomers has discovered a rare pair of brown dwarfs that has the widest separation of any brown dwarf binary system found to date.

"Because of their small size, brown dwarf binary systems are usually very close together," said Emma Softich, an undergraduate astrophysics student at the Arizona State University (ASU) School of Earth and Space Exploration and lead author of the study. "Finding such a widely separated pair is very exciting."

The gravitational force between a pair of brown dwarfs is lower than for a pair of stars with the same separation, so wide brown dwarf binaries are more likely to break up over time, making this pair of brown dwarfs an exceptional find.

The study, which is based on observations the University of California San Diego (UC San Diego) Cool Star Lab conducted with W. M. Keck Observatory on Maunakea, Hawai'i Island, is published in today's issue of The Astrophysical Journal Letters.

Using Keck Observatory's Near-Infrared Echellette Spectrometer, or NIRES instrument, members of the UC San Diego Cool Star Lab, including Physics Professor Adam Burgasser and graduate students Christian Aganze and Dino Hsu, obtained infrared spectra of the brown dwarf binary system, called CWISE J014611.20-050850.0AB. The data revealed the two brown dwarfs are about 12 billion miles apart, or three times the separation of Pluto from the Sun. This distance confirms the unusual brown dwarf couple breaks the record for having the widest separation from each other.

"Keck's exceptional sensitivity in the infrared with this instrument was critical for our measurements," said co-author Burgasser, who leads the Cool Star Lab. "The secondary brown dwarf of this system is exceptionally faint, but with Keck we were able to obtain good enough spectral data to classify both sources and identify them as members of a rare class of blue L dwarfs."

"Wide, low-mass systems like CWISE J014611.20-050850.0AB are usually disrupted early on in their lifetimes, so the fact that this one has survived until now is pretty remarkable," said co-author Adam Schneider of the U.S. Naval Observatory, Flagstaff Station and George Mason University.

Brown dwarfs are celestial objects that are smaller than a normal star. These objects are not massive enough to sustain nuclear fusion and shine like normal stars, but are hot enough to radiate energy.

Many brown dwarfs have been discovered with data from NASA's Wide-field Infrared Survey Explorer (WISE) via the Backyard Worlds: Planet 9 citizen science project, which solicits help from the public to search the WISE image data bank to find brown dwarfs and low-mass stars, some of the Sun's nearest neighbors.

For this study, the researchers inspected images of Backyard Worlds discoveries, where companion brown dwarfs may have been overlooked. In doing so, they discovered the rare CWISE J014611.20 050850.0AB brown dwarf binary system.

Softich went through about 3,000 brown dwarfs from Backyard Worlds one by one and compared the WISE images to other survey images, looking for evidence of a brown dwarf companion to the original target. The team then used data from the Dark Energy Survey (DES) to confirm that it was indeed a brown dwarf pair.

They then used Keck Observatory's NIRES to confirm the brown dwarfs have spectral types L4 and L8, and that they are at an estimated distance of about 40 parsecs, or 130.4 light-years from Earth, with a projected separation of 129 astronomical units, or 129 times the distance between the Sun and the Earth.

The team hopes this discovery will allow astronomers the chance to study brown dwarf binary systems and to develop models and procedures that will help in recognizing more of them in the future.

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How to look thousands of kilometers deep into the Earth

Researchers led by Sergey Lobanov from the GFZ German Research Centre for Geosciences have developed a new method to measure the density of silicon dioxide (SiO2) glass, one of the most important materials in industry and geology, at pressures of up to 110 gigapascals, 1.1 million times higher than normal atmospheric pressure. Instead of employing highly focused X-rays at a synchrotron facility, they used a white laser beam and a diamond anvil cell. The researchers report on their new and simple method in the current issue of Physical Review Letters.

The problem of density measurement under extreme conditions

In geosciences, the density of minerals, rocks, and melts at pressures up to several million atmospheres and temperatures of several thousand degrees is of critical importance because it governs the long-term planetary evolution as well as volcanic processes. But how can the density of a material be measured at such extreme conditions? To answer this question for a crystalline mineral or a rock, scientists use X-ray diffraction with which one measures the spacing between the periodically arranged atoms. There is, however, a problem if the material has a disordered structure, i.e. is non-crystalline, like glasses or molten rocks. In this case, the volume of the sample has to be measured directly -- the density of a material equals its mass divided by volume. However, such measurements are extremely difficult because of the tiny volume of the sample brought to high pressure. Previously, these measurements required large scale X-ray facilities and highly specialized equipment, thus being very expensive. Now, a team led by scientist Sergey Lobanov of the GFZ German Research Centre for Geosciences is introducing a new method in which a laser the size of a shoebox allows them to measure the volume of samples brought to pressures similar to that at the depth of more than 2000 km in the Earth.

Inside the Earth, the rock is under unimaginably high pressure, up to several million times higher than normal atmospheric pressure. However, contrary to widespread belief, the Earth's mantle is not liquid, but solid. The rock behaves in a viscoplastic fashion: It moves centimeter by centimeter per year, but it would burst under a hammer blow. Nevertheless, the slow movements drive the Earth's crustal plates and tectonics, which in turn trigger volcanism. Chemical changes, for example, caused by water squeezed out of subducted crustal plates, can change the melting point of the rock in such a way that suddenly molten magma is formed. When this magma makes its way to the Earth's crust and to the surface, volcanic eruptions occur.

Density of disordered materials

No instrument in the world can penetrate the Earth's mantle to study such processes in detail. Therefore, one must rely on calculations, seismic signals and laboratory experiments to learn more about the Earth's interior. A diamond anvil cell can be used to generate the extremely high pressures and temperatures that prevail there. The samples explored in it are smaller than the tip of a pin. Their volume is in the sub nanoliter range (e.g. at least 10 million times smaller than 1 milliliter). When material is compressed under such high pressures, the internal structure changes. To analyze this precisely, X-rays are used on crystals to generate diffraction patterns. This allows conclusions to be drawn about the volume of the crystal lattice and thus also the density of the material. Non-crystalline materials, such as glasses or molten rocks, have so far kept their innermost secrets to themselves. This is because for disordered materials X-ray diffraction does not provide direct information on their volume and density.

Simple trick: measurement with laser instead of X-ray beam

Using a simple trick, researchers led by Sergey Lobanov have now succeeded in measuring the refractive index and density of silicon dioxide (SiO2) glass, one of the most important materials in industry and geology, at pressures of up to 110 gigapascals. This is a pressure that prevails at a depth of more than 2,000 kilometers in the Earth's interior and is 1.1 million times higher than normal atmospheric pressure. The researchers used a multicolor laser to measure the brightness of its reflection from the pressurized sample. The brightness of the laser reflection contained information on the refractive index, a fundamental material property that describes how light slows down and bends as it travels through the material, but also the path length of the laser inside the sample. Materials with a high refractive index and density, such as diamonds and metals, typically appear bright and shiny to our eye. Instead of looking at the tiny samples with a naked eye, Lobanov and his colleagues used a powerful spectrometer to record changes in brightness at high pressure. These measurements yielded the refractive index of SiO2 glass and provided key information to quantify its density.

Significance of the density measurement of glasses for the geosciences

"Earth was a giant ball of molten rock 4.5 billion years ago. To understand how Earth has cooled and produced a solid mantle and crust, we need to know the physical properties of molten rocks at extreme pressure. However, studying melts at high pressure is extremely challenging and to circumvent some of these challenges geologists choose to study glasses instead of melts. Glasses are produced by quickly cooling hot but viscous melts. As a result, the structure of glasses often represents the structure of melts they were formed from. Previous measurements of glass density at high pressure required large and expensive synchrotron facilities that produce a tightly focused beam of X-rays that can be used to view the tiny sample in a diamond anvil cell. These were challenging experiments and only the densities of very few glasses have been measured to a pressure of 1 million atmospheres. We have now shown that the evolution of the sample volume and density of any transparent glass can be accurately measured up to pressures of at least 110 GPa using optical techniques," Lobanov says. "This can be done outside of synchrotron facilities and is therefore much easier and less costly. Our work thus paves the way to future studies of glasses that approximate Earth's present-day and long-gone melts. These future studies will provide new quantitative answers about the evolution of the early Earth as well as the driving forces behind volcanic eruptions."

New possibilities for the investigation of non-crystalline, initially non-transparent solids

Because the samples are extremely small and therefore ultra-thin, even materials that look like a lump of rock in large pieces become translucent. According to the researchers, these developments open up new possibilities for studying the mechanical and electronic properties of non-crystalline solids that appear nontransparent in larger volumes. According to the authors of the study, their findings have far-reaching implications for materials science and geophysics. In addition, this information could serve as a benchmark for computational studies of the transport properties of glasses and melts under extreme conditions.

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The formation of the West Antarctic Ice Sheet was very different than previously believed

Roughly 35 million years ago, Earth cooled rapidly. At roughly the same time, the Drake Passage formed between South America and the Antarctic, paving the way for the Antarctic Circumpolar Current. Thanks to these two factors, Antarctica was soon completely covered in ice. As a study from the Alfred Wegener Institute now shows, this massive glaciation was delayed in at least one region. This new piece of the puzzle concerning the early history of the West Antarctic Ice Sheet could help to predict its unstable future. The study was just released in the Nature journal Communications Earth & Environment.

For climate researchers, the West Antarctic has been in the spotlight for years. Here, the West Antarctic Ice Sheet lying atop the continent stretches to the adjacent Amundsen Sea. Near the coast, the ice is still in direct contact with the soil; farther toward the open sea, it floats. Because climate change progressively warms the seawater, the latter is increasingly eroding the ice shelf from below. The grounding line -the last point at which the ice still rests on the ground -moves farther and farther inland. Due to meltwater and calving icebergs, the Thwaites Glacier, which flows into the Amundsen Sea, now loses twice as much ice as 30 years ago. If the West Antarctic Ice Sheet were to collapse entirely, global sea levels would rise by more than three metres.

"The stability of the West Antarctic Ice Sheet is critical to the future development of the global sea level," says the study's first author, Gabriele Uenzelmann-Neben from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). "Accordingly, researchers around the world are working to predict the future behaviour of the ice in a warmer world using numerical simulation. The more we know about the history of the West Antarctic Ice Sheet, the more accurate we can make these models. Its more recent history is well-documented, but we still know very little about its earlier years -- particularly the formation phase. Our study delivers an important piece of the puzzle."

In the course of two research cruises on board the Polarstern, the Geophysicist and her team investigated sediments in the vicinity of Pine Island Trough, a channel-like furrow in the seafloor of the shallow part of the Amundsen Sea that stretches from north to south and leads directly toward the western coast of Antarctica. To collect data, the AWI team relied on the tried and proven reflection seismology method: the Polarstern towed a 3,000-metre-long measuring cable -- or streamer -- behind her. The streamer is equipped with hydrophones that utilise a total of 240 measuring channels. During survey cruises, an airgun is used to produce seismic pulses behind the ship. These pulses penetrate the seafloor and are reflected back at geological boundaries -- e.g. between the sediment and hard rock -- which is recorded by the streamer's hydrophones. Based on the different travel times for the waves and the respective positions of the individual channels, the internal structure of the seafloor can be mapped.

The measurement data revealed a large sediment body, a sediment drift, on the eastern flank of Pine Island Trough, one with no counterpart on its western side. "Because of the Coriolis effect produced by Earth's rotation, this asymmetrical deposition of a sediment drift on the trough's eastern side but not the western one can only have been produced by a deep-water current that flowed toward the coast from north to south," says Uenzelmann-Neben. "In order for that to occur, the ocean circulation at the time of the deposition had to be similar to today's conditions, that is, the prevailing westerlies and the Antarctic Circumpolar Current had to have been located far to the south. And similar to today, the deep water upwelled through the trough must have been comparatively warm."

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New fossil birds discovered near China’s Great Wall – one had a movable, sensitive 'chin'

Approximately 80 miles from the westernmost reach of China's Great Wall, paleontologists found relics of an even more ancient world. Over the last two decades, teams of researchers unearthed more than 100 specimens of fossil birds that lived approximately 120 million years ago, during the time of the dinosaurs. However, many of these fossils have proved difficult to identify: they're incomplete and sometimes badly crushed. In a new paper published in the Journal of Systematics and Evolution, researchers examined six of these fossils and identified two new species. And as a fun side note, one of those new species had a movable bony appendage at the tip of its lower jaw that may have helped the bird root for food.

"It was a long, painstaking process teasing out what these things were," says Jingmai O'Connor, the study's lead author and the associate curator of vertebrate paleontology at Chicago's Field Museum. "But these new specimens include two new species that increase our knowledge of Cretaceous bird faunas, and we found combinations of dental features that we've never seen in any other dinosaurs."

"These fossils come from a site in China that has produced fossils of birds that are pretty darned close to modern birds, but all the bird fossils described thus far haven't had skulls preserved with the bodies," says co-author Jerry Harris of Utah Tech University. "These new skull specimens help fill in that gap in our knowledge of the birds from this site and of bird evolution as a whole."

All birds are dinosaurs, but not all dinosaurs are birds; a small group of dinosaurs evolved into birds that coexisted with other dinosaurs for 90 million years. Modern birds are the descendants of the group of birds that survived the extinction that killed the rest of the dinosaurs, but many prehistoric birds went extinct then too. O'Connor's work focuses on studying different groups of early birds to figure out why some survived while others went extinct.

The fossil site in northwestern China, called Changma, is an important place for researchers like O'Connor studying bird evolution. It's the second-richest Mesozoic (time of the dinosaurs) fossil bird site in the world, but more than half of the fossils found there belong to the same species, Gansus yumenensis.Determining which fossils are Gansus and which ones aren't is tricky; the six specimens that O'Connor and her colleagues examined in this study are primarily just skulls and necks, parts not preserved in known specimens of Gansus. The fossils were also somewhat smushed by their time deep in the Earth, which made analyzing them difficult.

"The Changma site is a special place," says study co-author Matt Lamanna of Pittsburgh's Carnegie Museum of Natural History. "The fossil-bearing rocks there tend to split into thin sheets along ancient bedding planes. So, when you're digging, it's like you're literally turning back the pages of history, layer by layer uncovering animals and plants that haven't seen the light of day in roughly 120 million years."

"Because the specimens were pretty flattened, CT-scanning them and fully segmenting them could take years and might not even give you that much information, because these thin bones are flattened into almost the same plane, and then it just becomes almost impossible to figure out where the boundaries of these bones are," says O'Connor. "So we had to kind of work with what was exposed." Through painstaking work, the researchers were able to identify key features in the birds' jaws that showed that two of the six specimens were unknown to science.

The new species (or, more accurately, new genera -- genus is a step above species in the order scientists use to name organisms) are called Meemannavis ductrix and Brevidentavis zhangi. Meemannavis is named for Meemann Chang, a Chinese paleontologist who became the first woman to lead the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing. The name Brevidentavis means "short-toothed bird." Like Gansus, both Meemannavis and Brevidentavis are ornithuromorph birds -- the group that contains modern birds. Like today's birds, Meemannavis was toothless. Brevidentavis, on the other hand, had small, peg-like teeth packed close together in its mouth. Along with those teeth came another strange feature.

"Brevidentavis is an ornithuromorph bird with teeth, and in ornithuromorphs with teeth, there's a little bone at the front of the jaw called the predentary, where its chin would be if birds had chins," explains O'Connor. In a previous study on the predentary in another fossil bird, the authors figured out, by CT-scanning the bone and staining it with chemicals, that the predentary bone underwent stress and also found a kind of cartilage that only forms when there's movement.

"In this earlier study, we were able to tell that the predentary was capable of being moved, and that it would have been innervated -- Brevidentavis wouldn't just have been able to move its predentary, it would have been able to feel through it," says O'Connor. "It could have helped them detect prey. We can hypothesize that these toothed birds had little beaks with some kind of movable pincer at the tip of their jaws in front of the teeth."

Brevidentavis isn't the first fossil bird discovered with a predentary that might have been used in this way, but its existence, along with Meemannavis, helps round out our understanding of the diversity of prehistoric birds, especially in the Changma region.

The study also helps shed light on the most common bird from the site, Gansus, since at least four of the other specimens examined probably belong to this species. "Gansus is the first known true Mesozoic bird in the world, as Archaeopteryx is more dinosaur-like, and now we know what its skull looks like after about 40 years," notes Hai-Lu You of the IVPP.

"These amazing fossils are like a lockpick allowing us to open the door to greater knowledge of the evolutionary history of the skull in close relatives of living birds," says Tom Stidham, a co-author from the IVPP. "At a time when giant dinosaurs still roamed the land, these birds were the products of evolution experimenting with different lifestyles in the water, in the air, and on land, and with different diets as we can see in some species having or lacking teeth. Very few fossils of this geological age provide the level of anatomical detail that we can see in these ancient bird skulls."

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