Earth's first animals had particular taste in real estate

 Even without body parts that allowed for movement, new research shows -- for the first time -- that some of Earth's earliest animals managed to be picky about where they lived.

These creatures from the Ediacaran Period, roughly 550 million years ago, are strangely shaped soft-bodied animals that lived in the sea. Researchers have long considered them enigmatic.

"It's not like studying dinosaurs, which are related to birds that we can observe today," said Phillip C. Boan, UC Riverside paleontology graduate student and lead author of the new study. "With these animals, because they have no modern descendants, we're still working out basic questions about how they lived, such as how they reproduced and what they ate."

For this particular research project, the researchers focused on understanding where in the sea the animals spent their lives.

The ancient sea was also a largely foreign place compared to today's marine environments. It was dominated by a mat on the sea floor composed of bacteria and layers of other organic materials. In addition, predatory creatures were uncommon.

Given the alien nature of Ediacaran Earth, the researchers were surprised to find an animal that lived much the way barnacles do today. A new Paleobiology paper details how Obamus coronatus, named for the former U.S. president, opted to live on specific parts of the sea floor in the company of other Obamus.

The animal averaged about a half-inch in diameter and was "shaped like a French cruller donut with ribbons on top," Boan said. It did not move of its own accord, and likely spent its entire life embedded in its preferred spot on the sea floor.

"We think about the very oldest animals and maybe you wouldn't expect them to be so picky. But Obamus only occurs where there is a thick mat, and it's a pretty sophisticated way of making a living for something so very old," said Mary Droser, UCR distinguished professor of paleontology and study co-author.

In 2018, Droser's laboratory named the Obamus in honor of Barack Obama's passion for science. Her group discovered it at an extraordinarily well-preserved fossil site in the Australian Outback, at what is now called Nilpena Ediacara National Park.

A series of storms buried the Ediacaran sea floor at Nilpena in layers of sediment, helping preserve sandstone impressions of entire animal communities that lived together there. "This way, we're able to piece together whole ecosystems," Droser said. "Looking at them is like snorkeling around on the ancient sea floor, instead of looking at a single animal in a fish tank."

For this project, the research team selected three animals found in relatively large numbers at Nilpena, and examined how they were geographically distributed.

The other two animals, Tribrachidium and Rugoconites, are also immobile creatures with no modern descendants. "They are tri-radially symmetrical, like the Mercedes Benz logo," Boan said. "And they would have lived their entire lives embedded in the sea floor, as Obamus did."

Distribution for these other two animals was varied. Sometimes they could be found living in the company of other organisms like themselves, but not in every instance. However, Obamus displayed a clear preference.

"This is really the first example of a habitat-selective Ediacaran creature, the first example of a macroscopic animal doing this," Boan said. "But how did they get where they wanted to go? This is a question we don't yet know the answer to."

The research team theorizes that Obamus were likely motivated by the need to reproduce.

"There are a limited number of reproductive strategies, especially for animals like these," Droser said. "There are more strategies today, and they're more elaborate now. But the same ones used today were still being used 550 million years ago."

Obamus likely spread itself via selective larva that preferred locations with thick microbial mat and near other Obamus. "We don't entirely understand how Obamus offspring spread out, but we know that when they picked a place to live, it was very specific," Boan said.

A deeper understanding of how life on Earth developed over time can give researchers insight into how life could develop on another planet. For this reason, Droser's lab is funded by NASA's Exobiology program.

"This is our window into how a complex ecosystem forms," Boan said. "We only have Earth, and we need to use every part of its history when thinking about life, even way off in the cosmos.

Giants of the Jurassic seas were twice the size of a killer whale

 Over 20 years ago, the BBC's Walking with Dinosaurs TV documentary series showed a 25-metre long Liopleurodon. This sparked heated debates over the size of this pliosaur as it was thought to have been wildly overestimated and more likely to have only reached an adult size of just over six metres long.

The speculation was set to continue, but now a chance discovery in an Oxfordshire museum has led to University of Portsmouth palaeontologists publishing a paper on a similar species potentially reaching a whopping 14.4 metres -- twice the size of a killer whale.

Professor David Martill from the University of Portsmouth's School of the Environment, Geography and Geosciences, said: "I was a consultant for the BBC's pilot programme 'Cruel Sea' and I hold my hands up -- I got the size of Liopleurodon horrendously wrong. I based my calculations on some fragmentary material which suggested a Liopleurodon could grow to a length of 25 metres, but the evidence was scant and it caused a lot of controversy at the time.

"The size estimate on the BBC back in 1999 was overdone, but now we have some evidence that is much more reliable after a serendipitous discovery of four enormous vertebrate."

Professor Martill's co-author, Megan Jacobs, was photographing an ichthyosaur skeleton at Abingdon County Hall Museum, while Dave looked through drawers of fossils. He found a large vertebra and was thrilled to discover the curator had three more of them in storage.

The vertebrae are clearly identifiable as being closely related to a Pliosaurus species or similar animal. Pliosaurs were like plesiosaurs, but with a bigger elongated head, similar to a crocodile, and a shorter neck. They had four flippers, which acted as powerful paddles to propel them through water and a relatively short tail.

After conducting topographic scans, Professor Martill and colleagues calculated this Late Jurassic marine reptile could have grown to between 9.8 and 14.4 metres long.

He said: "We know these pliosaurs were very fearsome animals swimming in the seas that covered Oxfordshire 145-152 million years ago. They had a massive skull with huge protruding teeth like daggers -- as big, if not bigger than a T. rex, and certainly more powerful.

"They were at the top of the marine food chain and probably preyed on ichthyosaurs, long-necked plesiosaurs and maybe even smaller marine crocodiles, simply by biting them in half and taking chunks off them. We know they were massacring smaller marine reptiles because you can see bite marks in ichthyosaur bones in examples on display in The Etches Collection in Dorset."

The vertebrae were originally discovered during temporary excavations at Warren Farm in the River Thames Valley in Oxfordshire and come from the Kimmeridge Clay Formation. This deposit is Late Jurassic in age, around 152 million years old.

Professor Martill added: "It's wonderful to prove there was indeed a truly gigantic pliosaur species in the Late Jurassic seas. Although not yet on a par with the claims made for Liopleurodon in the iconic BBC TV series Walking With Dinosaurs, it wouldn't surprise me if one day we find some clear evidence that this monstrous species was even bigger."

Like ancient mariners, ancestors of Prochlorococcus microbes rode out to sea on exoskeleton particles

 Throughout the ocean, billions upon billions of plant-like microbes make up an invisible floating forest. As they drift, the tiny organisms use sunlight to suck up carbon dioxide from the atmosphere. Collectively, these photosynthesizing plankton, or phytoplankton, absorb almost as much CO2 as the world's terrestrial forests. A measurable fraction of their carbon-capturing muscle comes from Prochlorococcus -- an emerald-tinged free-floater that is the most abundant phytoplankton in the oceans today.

But Prochlorococcus didn't always inhabit open waters. Ancestors of the microbe likely stuck closer to the coasts, where nutrients were plentiful and organisms survived in communal microbial mats on the seafloor. How then did descendants of these coastal dwellers end up as the photosynthesizing powerhouses of the open oceans today?

MIT scientists believe that rafting was the key. In a new study they propose that ancestors of Prochlorococcus acquired an ability to latch onto chitin -- the degraded particles of ancient exoskeletons. The microbes hitched a ride on passing flakes, using the particles as rafts to venture further out to sea. These chitin rafts may have also provided essential nutrients, fueling and sustaining the microbes along their journey.

Thus fortified, generations of microbes may have then had the opportunity to evolve new abilities to adapt to the open ocean. Eventually, they would have evolved to a point where they could jump ship and survive as the free-floating ocean dwellers that live today.

"If Prochlorococcus and other photosynthetic organisms had not colonized the ocean, we would be looking at a very different planet," says Rogier Braakman, a research scientist in MIT's Department of Earth, Atmospheric, and Planetary Sciences (EAPS). "It was the fact they were able to attach to these chitin rafts that enabled them to establish a foothold in an entirely new and massive part of the planet's biosphere, in a way that changed the Earth forever."

Braakman and his collaborators present their new "chitin raft" hypothesis, along with experiments and genetic analyses supporting the idea, in a study appearing this week in PNAS.

MIT co-authors are Giovanna Capovilla, Greg Fournier, Julia Schwartzman, Xinda Lu, Alexis Yelton, Elaina Thomas, Jack Payette, Kurt Castro, Otto Cordero, and MIT Institute Professor Sallie (Penny) Chisholm, along with colleagues from multiple institutions including the Woods Hole Oceanographic Institution.

A strange gene

Prochlorococcus is one of two main groups belonging to a class known as picocyanobacteria, which are the smallest photosynthesizing organisms on the planet. The other group is Synechococcus, a closely related microbe that can be found abundantly in ocean and freshwater systems. Both organisms make a living through photosynthesis.

But it turns out that some strains of Prochlorococcus can adopt alternative lifestyles, particularly in low-lit regions where photosynthesis is difficult to maintain. These microbes are "mixotrophic," using a mix of other carbon-capturing strategies to grow.

Researchers in Chisholm's lab were looking for signs of mixotrophy when they stumbled on a common gene in several modern strains of Prochlorococcus. The gene encoded the ability to break down chitin, a carbon-rich material that comes from the sloughed-off shells of arthropods, such as insects and crustaceans.

"That was very strange," says Capovilla, who decided to dig deeper into the finding when she joined the lab as a postdoc.

For the new study, Capovilla carried out experiments to see whether Prochlorococcus can in fact break down chitin in a useful way. Previous work in the lab showed that the chitin-degrading gene appeared in strains of Prochlorococcus that live in low-light conditions, and in Synechococcus. The gene was missing in Prochlorococcus inhabiting more sunlit regions.

In the lab, Capovilla introduced chitin particles into samples of low-light and high-light strains. She found that microbes containing the gene could degrade chitin, and of these, only low-light-adapted Prochlorococcus seemed to benefit from this breakdown, as they appeared to also grow faster as a result. The microbes could also stick to chitin flakes -- a result that particularly interested Braakman, who studies the evolution of metabolic processes and the ways they have shaped the Earth's ecology.

"People always ask me: How did these microbes colonize the early ocean?" he says. "And as Gio was doing these experiments, there was this 'aha' moment."

Braakman wondered: Could this gene have been present in the ancestors of Prochlorococcus, in a way that allowed coastal microbes to attach to and feed on chitin, and ride the flakes out to sea?

It's all in the timing

To test this new "chitin raft" hypothesis, the team looked to Fournier, who specializes in tracing genes across species of microbes through history. In 2019, Fournier's lab established an evolutionary tree for those microbes that exhibit the chitin-degrading gene. From this tree, they noticed a trend: Microbes start using chitin only after arthropods become abundant in a particular ecosystem.

For the chitin raft hypothesis to hold, the gene would have to be present in ancestors of Prochlorococcus soon after arthropods began to colonize marine environments.

The team looked to the fossil record and found that aquatic species of arthropods became abundant in the early Paleozoic, about half a billion years ago. According to Fournier's evolutionary tree, that also happens to be around the time that the chitin-degrading gene appears in common ancestors of Prochlorococcus and Synecococchus.

"The timing is quite solid," Fournier says. "Marine systems were becoming flooded with this new type of organic carbon in the form of chitin, just as genes for using this carbon spread across all different types of microbes. And the movement of these chitin particles suddenly opened up the opportunity for microbes to really make it out to the open ocean."

The appearance of chitin may have been especially beneficial for microbes living in low-light conditions, such as along the coastal seafloor, where ancient picocyanobacteria are thought to have lived. To these microbes, chitin would have been a much-needed source of energy, as well as a way out of their communal, coastal niche.

Braakman says that once out at sea, the rafting microbes were sturdy enough to develop other ocean-dwelling adaptations. Millions of years later, the organisms were then ready to "take the plunge" and evolve into the free-floating, photosynthesizing Prochlorococcus that exist today.

"In the end, this is about ecosystems evolving together," Braakman says. "With these chitin rafts, both arthropods and cyanobacteria were able to expand into the open ocean. Ultimately, this helped to seed the rise of modern marine ecosystems."

Culprit behind destruction of New York's first dinosaur museum revealed

 A new paper from the University of Bristol rewrites the history of the darkest, most bizarre event in the history of palaeontology.

In New York, in May of 1871, the partially built, life-size models of dinosaurs and other prehistoric creatures destined for a prestigious new museum in Central Park were totally destroyed in a violent act of malicious vandalism by a gang of thugs with sledgehammers. The shattered pieces were carted away and buried somewhere in the park, never to be seen again.

Until now, the heinous act had been tributed to former American politician William 'Boss' Tweed.

But now, a new paper from Ms Victoria Coules of Bristol's Department of History of Art and Professor Michael Benton of Bristol's School of Earth Sciences sheds new light on the incident and, contrary to previous accounts, identifies who was really behind the order and what drove them to such wanton destruction -- an odd man known as Henry Hilton, the Treasurer and VP of Central Park.

"It's all to do with the struggle for control of New York city in the years following the American Civil War (1861-1865)," said Ms Coules. "The city was at the centre of a power struggle -- a battle for control of the city's finances and lucrative building and development contracts."

As the city grew, the iconic Central Park was taking shape. More than just a green space, it was to have other attractions, including the Paleozoic Museum. British sculptor Benjamin Waterhouse Hawkins, who had created the Crystal Palace Dinosaurs, the life-size models of prehistoric creatures in London -- had travelled to America and was commissioned to build American versions of the models for the Paleozoic museum.

But the notorious William "Boss" Tweed had taken command of the city and, in sweeping changes to the city's governance, put his own henchmen in charge of city departments -- including Central Park. They cancelled the partially complete project in late 1870, and there the matter would have lain but in May 1871 someone ordered the gang of workmen to destroy all of its partly finished contents.

Professor Benton explains: "Previous accounts of the incident had always reported that this was done under the personal instruction of "Boss" Tweed himself, for various motives from raging that the display would be blasphemous, to vengeance for a perceived criticism of him in a New York Times report of the project's cancellation."

"Reading these reports, something didn't look right," Ms Coules said. "At the time Tweed was fighting for his political life, already accused of corruption and financial wrong-doings, so why was he so involved in a museum project?" She added, "So we went back to the original sources and found that it wasn't Tweed -- and the motive was not blasphemy or hurt vanity."

The situation was complicated by two other projects in development at the same time in Central Park, the American Museum of Natural History (AMNH) and the Central Park Zoo. But, as Professor Benton explained, "drawing on the detailed annual reports and minutes of Central Park, along with reports in the New York Times, we can show that the real villain was one strange character by the name of Henry Hilton."

Ms Coules adds: "Because all the primary sources are now available online, we could study them in detail -- and we could show that the destruction was ordered in a meeting by the real culprit, Henry Hilton, the Treasurer and VP of Central Park -- and it was carried out the day after this meeting."

Hilton was already notorious for other eccentric decisions. When he noticed a bronze statue in the Park, he ordered it painted white, and when a whale skeleton was donated to the American Museum of Natural History, he had that painted white as well. Later in life, other ill-judged decisions included cheating a widow out of her inheritance, squandering a huge fortune, and trashing businesses and livelihoods along the way.

Professor Benton concluded: "This might seem like a local act of thuggery but correcting the record is hugely important in our understanding of the history of palaeontology. We show it wasn't blasphemy, or an act of petty vengeance by William Tweed, but the act of a very strange individual who made equally bizarre decisions about how artefacts should be treated -- painting statues or whale skeletons white and destroying the museum models. He can be seen as the villain of the piece but as character, Hilton remains an enigmatic mystery."

Hidden supermassive black holes brought to life by galaxies on collision course

 Astronomers have found that supermassive black holes obscured by dust are more likely to grow and release tremendous amounts of energy when they are inside galaxies that are expected to collide with a neighbouring galaxy. The new work, led by researchers from Newcastle University, is published in Monthly Notices of the Royal Astronomical Society.

Galaxies, including our own Milky Way, contain supermassive black holes at their centres. They have masses equivalent to millions, or even billions, times that of our Sun. These black holes grow by ‘eating’ gas that falls on to them. However, what drives the gas close enough to the black holes for this to happen is an ongoing mystery.

One possibility is that when galaxies are close enough together, they are likely to be gravitationally pulled towards each other and ‘merge’ into one larger galaxy.

In the final stages of its journey into a black hole, gas lights up and produces a huge amount of energy. This energy is typically detected using visible light or X-rays. However, the astronomers conducting this study were only able to detect the growing black holes using infrared light. The team made use of data from many different telescopes, including the Hubble Space Telescope and infrared Spitzer Space Telescope.

The researchers developed a new technique to determine how likely it is that two galaxies are very close together and are expected to collide in the future. They applied this new method to hundreds of thousands of galaxies in the distant universe (looking at galaxies formed 2 to 6 billion years after the Big Bang) in an attempt to better understand the so-called ‘cosmic noon’, a time when most of the Universe’s galaxy and black hole growth is expected to have taken place.

Understanding how black holes grew during this time is fundamental in modern day galactic research, especially as it may give us an insight into the supermassive black hole situated inside the Milky Way, and how our galaxy evolved over time.

As they are so far away, only a small number of cosmic noon galaxies meet the required criteria to get precise measurements of their distances. This makes it very difficult to know with high precision if any two galaxies are very close to each other.

This study presents a new statistical method to overcome the previous limitations of measuring accurate distances of galaxies and supermassive black holes at cosmic noon. It applies a statistical approach to determine galaxy distances using images at different wavelengths and removes the need for spectroscopic distance measurements for individual galaxies.

Data arriving from the James Webb Space Telescope over the coming years is expected to revolutionise studies in the infrared and reveal even more secrets about how these dusty black holes grow.

Sean Dougherty, postgraduate student at Newcastle University and lead author of the paper, says, “Our novel approach looks at hundreds of thousands of distant galaxies with a statistical approach and asks how likely any two galaxies are to be close together and so likely to be on a collision course.”

Dr Chris Harrison, co-author of the study, “These supermassive black holes are very challenging to find because the X-ray light, which astronomers have typically used to find these growing black holes, is blocked, and not detected by our telescopes. But these same black holes can be found using infrared light, which is produced by the hot dust surrounding them.”

He adds, “The difficulty in finding these black holes and in establishing precise distance measurements explains why this result has previously been challenging to pin down these distant ‘cosmic noon’ galaxies. With JWST we are expecting to find many more of these hidden growing black holes. JWST will be far better at finding them, therefore we will have many more to study, including ones that are the most difficult to find. From there, we can do more to understand the dust that surrounds them, and find out how many are hidden in distant galaxies.”

Researchers find new approach to explore earliest universe dynamics with gravitational waves

 Researchers have discovered a new generic production mechanism of gravitational waves generated by a phenomenon known as oscillons, which can originate in many cosmological theories from the fragmentation into solitonic "lumps" of the inflaton field that drove the early Universe's rapid expansion, reports a new study published in Physical Review Letters.

The results have set the stage for revealing exciting novel insights about the Universe's earliest moments.

The inflationary period, which occurred just after the Big Bang, is believed to have caused the Universe to expand exponentially. In many cosmological theories, the rapid expansion period is followed by the formation of oscillons. Oscillons are a type of localized non-linear massive structure that can form from fields, such as the inflaton field, which are oscillating at high frequencies. These structures can persist for long periods, and as the researchers found, their eventual decay can generate a significant amount of gravitational waves, which are ripples in space-time.

In their study, Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) Project Researcher Kaloian D. Lozanov, and Kavli IPMU Visiting Associate Scientist, International Center for Quantum-field Measurement Systems for Studies of the Universe and Particles (QUP) Senior Scientist, and High Energy Accelerator Research Organization (KEK) Theory Center Assistant Professor Volodymyr Takhistov, simulated the evolution of the inflaton field during the early Universe and found that oscillons were indeed present. They then found that oscillon decay was able to generate gravitational waves that would be detectable by upcoming gravitational wave observatories.

The findings provide a novel test of the early Universe dynamics independent of the conventionally studied cosmic microwave background radiation. The discovery of these gravitational waves would establish a new window into the Universe's earliest moments, and could help shed light on some of the pressing fundamental questions in cosmology.

With the ongoing development of gravitational wave detectors and supercomputing resources, we can expect to gain even more insights into the Universe's early moments in the coming years. Overall, the new study demonstrates the power of combining theoretical models with advanced computational techniques and observations to uncover new insights into the Universe's evolution.

Astronomers reveal the largest cosmic explosion ever seen

 A team of astronomers led by the University of Southampton have uncovered the largest cosmic explosion ever witnessed.

The explosion is more than ten times brighter than any known supernova (exploding star) and three times brighter than the brightest tidal disruption event, where a star falls into a supermassive black hole.

The explosion, known as AT2021lwx, has currently lasted over three years, compared to most supernovae which are only visibly bright for a few months. It took place nearly 8 billion light years away, when the universe was around 6 billion years old, and is still being detected by a network of telescopes.

The researchers believe that the explosion is a result of a vast cloud of gas, possibly thousands of times larger than our sun, that has been violently disrupted by a supermassive black hole. Fragments of the cloud would be swallowed up, sending shockwaves through its remnants, as well as into a large dusty 'doughnut' surrounding the black hole. Such events are very rare and nothing on this scale has been witnessed before.

Last year, astronomers witnessed the brightest explosion on record -- a gamma-ray burst known as GRB 221009A. While this was brighter than AT2021lwx, it lasted for just a fraction of the time, meaning the overall energy released by the AT2021lwx explosion is far greater.

The findings of the research have been published today [Friday, 12 May 2023] in Monthly Notices of the Royal Astronomical Society.

Discovery

AT2021lwx was first detected in 2020 by the Zwicky Transient Facility in California, and subsequently picked up by the Asteroid Terrestrial-impact Last Alert System (ATLAS) based in Hawaii. These facilities survey the night sky to detect transient objects that rapidly change in brightness indicating cosmic events such as supernovae, as well as finding asteroids and comets. Until now the scale of the explosion has been unknown.

"We came upon this by chance, as it was flagged by our search algorithm when we were searching for a type of supernova," says Dr Philip Wiseman, Research Fellow at the University of Southampton, who led the research. "Most supernovae and tidal disruption events only last for a couple of months before fading away. For something to be bright for two plus years was immediately very unusual."

The team investigated the object further with several different telescopes: the Neil Gehrels Swift Telescope (a collaboration between NASA, the UK and Italy), the New Technology Telescope (operated by the European Southern Observatory) in Chile, and the Gran Telescopio Canarias in La Palma, Spain.

Measuring the explosion

By analysing the spectrum of the light, splitting it up into different wavelengths and measuring the different absorption and emission features of the spectrum, the team were able to measure the distance to the object.

"Once you know the distance to the object and how bright it appears to us, you can calculate the brightness of the object at its source. Once we'd performed those calculations, we realised this is extremely bright," says Professor Sebastian Hönig from the University of Southampton, a co-author of the research.

The only things in the universe that are as bright as AT2021lwx are quasars -- supermassive black holes with a constant flow of gas falling onto them at high velocity.

Professor Mark Sullivan, also of the University of Southampton and another co-author of the paper, explains: "With a quasar, we see the brightness flickering up and down over time. But looking back over a decade there was no detection of AT2021lwx, then suddenly it appears with the brightness of the brightest things in the universe, which is unprecedented."

What caused the explosion?

There are different theories as to what could have caused such an explosion, but the Southampton-led team believe the most feasible explanation is an extremely large cloud of gas (mostly hydrogen) or dust that has come off course from its orbit around the black hole and been sent flying in.

The team are now setting out to collect more data on the explosion -- measuring different wavelengths, including X-rays which could reveal the object's surface and temperature, and what underlying processes are taking place. They will also carry out upgraded computational simulations to test if these match their theory of what caused the explosion.

Dr Philip Wiseman added: "With new facilities, like the Vera Rubin Observatory's Legacy Survey of Space and Time, coming online in the next few years, we are hoping to discover more events like this and learn more about them. It could be that these events, although extremely rare, are so energetic that they are key processes to how the centres of galaxies change over time."

 A new study led by physicist Sascha Kempf at the University of Colorado Boulder has delivered the strongest evidence yet that Saturn's rings are remarkably young -- potentially answering a question that has boggled scientists for well over a century.

The research, to be published May 12 in the journal Science Advances, pegs the age of Saturn's rings at no more than 400 million years old. That makes the rings much younger than Saturn itself, which is about 4.5 billion years old.

"In a way, we've gotten closure on a question that started with James Clerk Maxwell," said Kempf, associate professor in the Laboratory for Atmospheric and Space Physics (LASP) at CU Boulder.

The researchers arrived at that closure by studying what might seem like an unusual subject: dust.

Kempf explained that tiny grains of rocky material wash through Earth's solar system on an almost constant basis. In some cases, this flux can leave behind a thin layer of dust on planetary bodies, including on the ice that makes up Saturn's rings.

In the new study, he and his colleagues set out to put a date on Saturn's rings by studying how rapidly this layer of dust builds up -- a bit like telling how old a house is by running your finger along its surfaces.

"Think about the rings like the carpet in your house," Kempf said. "If you have a clean carpet laid out, you just have to wait. Dust will settle on your carpet. The same is true for the rings."

It was an arduous process: From 2004 to 2017, the team used an instrument called the Cosmic Dust Analyzer aboard NASA's late Cassini spacecraft to analyze specks of dust flying around Saturn. Over those 13 years, the researchers collected just 163 grains that had originated from beyond the planet's close neighborhood. But it was enough. Based on their calculations, Saturn's rings have likely been gathering dust for only a few hundred million years.

The planet's rings, in other words, are new phenomena, arising (and potentially even disappearing) in what amounts to a blink of an eye in cosmic terms.

"We know approximately how old the rings are, but it doesn't solve any of our other problems," Kempf said. "We still don't know how these rings formed in the first place."

From Galileo to Cassini

Researchers have been captivated by these seemingly-translucent rings for more than 400 years. In 1610, Italian astronomer Galileo Galilei first observed the features through a telescope, although he didn't know what they were. (Galileo's original drawings make the rings look a bit like the handles on a water jug). In the 1800s, Maxwell, a scientist from Scotland, concluded that Saturn's rings couldn't be solid but were, instead, made up of many individual pieces.

Today, scientists know that Saturn hosts seven rings comprised of countless chunks of ice, most no bigger than a boulder on Earth. Altogether, this ice weighs about half as much as Saturn's moon Mimas and stretches nearly 175,000 miles from the planet's surface.

Kempf added that for most of the 20th Century, scientists assumed that the rings likely formed at the same time as Saturn.

But that idea raised a few issues -- namely, Saturn's rings are sparkling clean. Observations suggest that these features are made up of roughly 98% pure water ice by volume, with only a tiny amount of rocky matter.

"It's almost impossible to end up with something so clean," Kempf said.

Cassini offered an opportunity to put a definitive age on Saturn's rings. The spacecraft first arrived at Saturn in 2004 and collected data until it purposefully crashed into the planet's atmosphere in 2017. The Cosmic Dust Analyzer, which was shaped a bit like a bucket, scooped up small particles as they whizzed by.

Engineers and scientists at LASP designed and built a much more sophisticated dust analyzer for NASA's upcoming Europa Clipper mission, which is scheduled to launch in 2024.

The team estimated that this interplanetary grime would contribute far less than a gram of dust to each square foot of Saturn's rings every year -- a light sprinkle, but enough to add up over time. Previous studies had also suggested that the rings could be young but didn't include definitive measures of dust accumulation.

Stroke of luck

The rings might already be vanishing. In a previous study, NASA scientists reported that the ice is slowly raining down onto the planet and could disappear entirely in another 100 million years.

That these ephemeral features existed at a time when Galileo and the Cassini spacecraft could observe them seems almost too good to be true, Kempf said -- and it begs an explanation for how the rings formed in the first place. Some scientists, for example, have posited that Saturn's rings may have formed when the planet's gravity tore apart one of its moons.

"If the rings are short lived and dynamical, why a

Global research reveals countries where record-breaking heatwaves are likely to cause most harm

 A new study has highlighted under-prepared regions across the world most at risk of the devastating effects of scorching temperatures.

The University of Bristol-led research, published today in Nature Communications, shows that unprecedented heat extremes combined with socioeconomic vulnerability puts certain regions, such as Afghanistan, Papua New Guinea, and Central America,most in peril.

Countries yet to experience the most intense heatwaves are often especially susceptible, as adaptation measures are often only introduced after the event. A high chance of record-breaking temperatures, growing populations, and limited healthcare and energy provision, increase the risks.

Beijing and Central Europe are also on the list of hotspots, as if record-breaking heatwaves occurred in these densely populated regions millions of people would be adversely affected.

In light of the findings, the researchers are calling for policy makers in hotspot regions to consider relevant action plans to reduce the risk of deaths and associated harms from climate extremes.

Lead author, climate scientist Dr Vikki Thompson at the University of Bristol Cabot Institute for the Environment, said: "As heatwaves are occurring more often we need to be better prepared. We identify regions that may have been lucky so far -- some of these regions have rapidly growing populations, some are developing nations, some are already very hot. We need to ask if the heat action plans for these areas are sufficient."

The researchers used extreme value statistics -- a method to estimate the return periods of rare events -- and large datasets from climate models and observations to pinpoint regions globally where temperature records are most likely to be broken soonest and the communities consequently in greatest danger of experiencing extreme heat.

The researchers also cautioned that statistically implausible extremes, when current records are broken by margins that seemed impossible until they occurred, could happen anywhere. These unlikely events were found to have transpired in almost a third (31%) of the regions assessed where observations were deemed reliable enough between 1959 and 2021, such as the 2021 Western North America heatwave.

Co-author Dann Mitchell, Professor in Atmospheric Sciences at the University of Bristol Cabot Institute for the Environment, said: "Being prepared saves lives. We have seen some of the most unexpected heatwaves around the world lead to heat-related deaths in the tens of thousands. In this study, we show that such record smashing events could occur anywhere. Governments around the world need to be prepared."

Human-induced climate change is causing an increase in the frequency, intensity, and duration of heatwaves, which have the potential to lead to thousands more excess deaths globally.

Improving our understanding of where society may not be ready for climate extremes can help prioritise mitigation in the most vulnerable regions. In recognition of the dangerous consequences of climate change, evidenced by the work of its climate experts, in 2019 the University of Bristol became the first UK university to declare a climate emergency.

Why this bird flu is different: Scientists say new avian influenza requires urgent coordinated response

 A highly pathogenic avian influenza has been spreading in the U.S., making headlines as the price of eggs soared at the start of the year and fears of the next zoonotic pandemic creep into popular media. A University of Maryland (UMD)-led team of researchers tracked the arrival and progression of the deadly bird flu (H5N1) in North America to determine how this outbreak is different from previous ones.

The team found that the deadly impact on wild birds and a shift from seasonal to year-round infections signal dangerous changes in avian influenza in the U.S. They concluded that there is an urgent need for unprecedented coordination at a national and regional-scale to manage the spread of a disease reaching across jurisdictions and disciplines. The team also suggests that H5N1 will likely become endemic, potentially posing risks to food security and the economy.

The paper was published April 19, 2023, in the journal Conservation Biology.

"We've been dealing with low pathogenic avian influenza for decades in the poultry industry, but this is different." said Jennifer Mullinax, assistant professor in the UMD Department of Environmental Science & Technology and a co-author of the study. Low pathogenic disease is less contagious and easier to contain than the highly pathogenic variety.

"This high pathogenic virus is wiping out everything in numbers that we've never seen before," Mullinax said. "This paper illustrates how unprecedented it is, and describes what we think is coming. It's really a call to arms saying, we can't afford to address this from our individual silos. Federal agencies, state agencies, the agriculture sector and wildlife management, we are all going to have to deal with this together, because we can't afford not to."

The team's conclusions are based on an analysis of five different data sources that provide information on the incidence of highly pathogenic avian influenza in wild birds and poultry focusing on the USA and Canada as well as a global database from 2014 through early 2023.

The data show the progression of highly pathogenic H5N1 as it spread from Eurasia to the U.S. where it was first documented in late 2021. By October 2022, the disease had resulted in 31 reported wild bird mass mortalities, accounting for an estimated 33,504 wild bird detections in the U.S. and Canada. In addition, more than 58 million domestic poultry were infected or had to be culled to limit the spread of infection in the U.S. and 7 million in Canada.

In 2015, an outbreak of highly pathogenic H5N8 in the U.S. led to the culling of 50 million poultry birds. But the disease was eradicated in North America that same year, largely because it did not seriously impact wild birds, which made containment through culling poultry relatively easy. But H5N1 poses new challenges.

"Unlike H5N8, this disease is heavily impacting wild birds," said Johanna Harvey, a postdoctoral researcher at UMD and lead author of the study. "It's difficult to estimate how many birds are truly affected across wild populations, but we're seeing dramatic disease impacts in raptors, sea birds and colonial nesting birds. And we now have the highest amount of poultry loss to avian influenza, so this is a worst-case scenario."

The data also reveals a shift from a seasonal to a year-round disease. Previous outbreaks of avian influenza -- whether low pathogenic virus that is endemic in the U.S. or highly pathogenic H5N8 in 2015 -- typically occurred in the fall, which meant farmers could prepare for seasonal outbreaks, cull flocks to halt the spread of disease, and have nearly a full year to recover losses. But this new virus appears sustained throughout the year, with summertime disease detections in wild birds and poultry outbreaks occurring in both the spring and fall.

Although declaring a disease endemic is a complicated process, the authors of the study suggest that the U.S. will likely follow patterns seen in Europe where highly pathogenic avian influenza is already being treated as an endemic disease rather than something that can be eradicated.

The research team recommends a management approach based on a method called Structured Decision-Making, which follows a specific process of identifying and bringing together relevant individuals with an interest, expertise or stake in an issue, distinguishing the unknown from the known factors and establishing measurable goals and actions with quantifiable results. The process is much like dealing with a human pandemic.

"Good decision science is what you do when you don't know what is going to happen next," said Mullinax, who teaches decision-making science. "This is a novel virus for North American birds, so no one knows if their immune systems will adapt, or how long that will take, or what that will look like. Where do we direct our funds for maximum benefit? Is it a vaccine? How do we track it in wild birds? Do we test the water or the soil? What are the triggers for different actions, and how do we measure if we're succeeding? These decisions have to be made on multiple scales."

Information 'deleted' from the human genome may be what made us human

 What the human genome is lacking compared with the genomes of other primates might have been as crucial to the development of humankind as what has been added during our evolutionary history, according to a new study led by researchers at Yale and the Broad Institute of MIT and Harvard.

The new findings, published April 28 in the journal Science, fill an important gap in what is known about historical changes to the human genome. While a revolution in the capacity to collect data from genomes of different species has allowed scientists to identify additions that are specific to the human genome -- such as a gene that was critical for humans to develop the ability to speak -- less attention has been paid to what's missing in the human genome.

For the new study researchers used an even deeper genomic dive into primate DNA to show that the loss of about 10,000 bits of genetic information -- most as small as a few base pairs of DNA -- over the course of our evolutionary history differentiate humans from chimpanzees, our closest primate relative. Some of those "deleted" pieces of genetic information are closely related to genes involved in neuronal and cognitive functions, including one associated with the formation of cells in the developing brain.

These 10,000 missing pieces of DNA -- which are present in the genomes of other mammals -- are common to all humans, the Yale team found.

The fact that these genetic deletions became conserved in all humans, the authors say, attests to their evolutionary importance, suggesting that they conferred some biological advantage.

"Often we think new biological functions must require new pieces of DNA, but this work shows us that deleting genetic code can result in profound consequences for traits make us unique as a species," said Steven Reilly, an assistant professor of genetics at Yale School of Medicine and senior author of the paper.

The paper was one of several published in Science from the Zoonomia Project, an international research collaboration that is cataloging the diversity in mammalian genomes by comparing DNA sequences from 240 species of mammals that exist today.

In their study, the Yale team found that some genetic sequences found in the genomes of most other mammal species, from mice to whales, vanished in humans. But rather than disrupt human biology, they say, some of these deletions created new genetic encodings that eliminated elements that would normally turn genes off.

The deletion of this genetic information, Reilly said, had an effect that was the equivalent of removing three characters -- "n't" -- from the word "isn't" to create a new word, "is."

"[Such deletions] can tweak the meaning of the instructions of how to make a human slightly, helping explain our bigger brains and complex cognition," he said.

The researchers used a technology called Massively Parallel Reporter Assays (MPRA), which can simultaneously screen and measure the function of thousands of genetic changes among species.

"These tools have the capability to allow us to start to identify the many small molecular building blocks that make us unique as a species," Reilly said.

Novel ultrasound uses microbubbles to open blood-brain barrier to treat glioblastoma in humans

 A major impediment to treating the deadly brain cancer glioblastoma has been that the most potent chemotherapy can't permeate the blood-brain barrier to reach the aggressive brain tumor.

But now Northwestern Medicine scientists report results of the first in-human clinical trial in which they used a novel, skull-implantable ultrasound device to open the blood-brain barrier and repeatedly permeate large, critical regions of the human brain to deliver chemotherapy that was injected intravenously.

The four-minute procedure to open the blood-brain barrier is performed with the patient awake, and patients go home after a few hours. The results show the treatment is safe and well tolerated, with some patients getting up to six cycles of treatment.

This is the first study to successfully quantify the effect of ultrasound-based blood-brain barrier opening on the concentrations of chemotherapy in the human brain. Opening the blood-brain barrier led to an approximately four- to six-fold increase in drug concentrations in the human brain, the results showed.

Scientists observed this increase with two different powerful chemotherapy drugs, paclitaxel and carboplatin. The drugs are not used to treat these patients because they do not cross blood-brain barrier in normal circumstances.

In addition, this is the first study to describe how quickly the blood-brain barrier closes after sonication. Most of the blood-brain barrier restoration happens in the first 30 to 60 minutes after sonication, the scientists discovered. The findings will allow optimization of the sequence of drug delivery and ultrasound activation to maximize the drug penetration into the human brain, the authors said.

"This is potentially a huge advance for glioblastoma patients," said lead investigator Dr. Adam Sonabend, an associate professor of neurological surgery at Northwestern University Feinberg School of Medicine and a Northwestern Medicine neurosurgeon.

Temozolomide, the current chemotherapy used for glioblastoma, does cross the blood-brain barrier, but is a weak drug, Sonabend said.

The paper will be published May 2 in The Lancet Oncology.

The blood-brain barrier is a microscopic structure that shields the brain from the vast majority of circulating drugs. As a result, the repertoire of drugs that can be used to treat brain diseases is very limited. Patients with brain cancer cannot be treated with most drugs that are otherwise effective for cancer elsewhere in the body, as these do not cross the blood-brain barrier. Effective repurposing of drugs to treat brain pathology and cancer require their delivery to the brain.

In the past, studies that injected paclitaxel directly into the brain of patients with these tumors observed promising signs of efficacy, but the direct injection was associated with toxicity such as brain irritation and meningitis, Sonabend said.

Blood-brain barrier recloses after an hour

The scientists discovered that the use of ultrasound and microbubble-based opening of the blood-brain barrier is transient, and most of the blood-brain barrier integrity is restored within one hour after this procedure in humans.

"There is a critical time window after sonification when the brain is permeable to drugs circulating in the bloodstream," Sonabend said.

Previous human studies showed that the blood-brain barrier is completely restored 24 hours after brain sonication, and based on some animal studies, the field assumed that the blood-brain barrier is open for the first six hours or so. The Northwestern study shows that this time window might be shorter.

In another first, the study reports that using a novel skull-implantable grid of nine ultrasound emitters designed by French biotech company Carthera opens the blood-brain barrier in a volume of brain that is nine times larger than the initial device (a small single-ultrasound emitter implant). This is important because to be effective, this approach requires coverage of a large region of the brain adjacent to the cavity that remains in the brain after removal of glioblastoma tumors.

Clinical trial for patients with recurrent glioblastoma

The findings of the study are the basis for an ongoing phase 2 clinical trial the scientists are conducting for patients with recurrent glioblastoma. The objective of the trial -- in which participants receive a combination of paclitaxel and carboplatin delivered to their brain with the ultrasound technique -- is to investigate whether this treatment prolongs survival of these patients. A combination of these two drugs is used in other cancers, which is the basis for combining them in the phase 2 trial.

In the phase 1 clinical trial reported in this paper, patients underwent surgery for resection of their tumors and implantation of the ultrasound device. They started treatment within a few weeks after the implantation.

Scientists escalated the dose of paclitaxel delivered every three weeks with the accompanying ultrasound-based blood-brain barrier opening. In subsets of patients, studies were performed during surgery to investigate the effect of this ultrasound device on drug concentrations. The blood-brain barrier was visualized and mapped in the operating room using a fluorescent die called fluorescein and by MRI obtained after ultrasound therapy.