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Scientists have spotted the farthest galaxy ever

An international team of astronomers, including researchers at the Center for Astrophysics | Harvard & Smithsonian, has spotted the most distant astronomical object ever: a galaxy.

Named HD1, the galaxy candidate is some 13.5 billion light-years away and is described Thursday in the Astrophysical Journal. In an accompanying paper published in the Monthly Notices of the Royal Astronomical Society Letters, scientists have begun to speculate exactly what the galaxy is.

The team proposes two ideas: HD1 may be forming stars at an astounding rate and is possibly even home to Population III stars, the universe’s very first stars—which, until now, have never been observed. Alternatively, HD1 may contain a supermassive black hole about 100 million times the mass of our Sun.

“Answering questions about the nature of a source so far away can be challenging,” says Fabio Pacucci, lead author of the MNRAS study, co-author in the discovery paper on ApJ, and an astronomer at the Center for Astrophysics. “It’s like guessing the nationality of a ship from the flag it flies, while being faraway ashore, with the vessel in the middle of a gale and dense fog. One can maybe see some colors and shapes of the flag, but not in their entirety. It’s ultimately a long game of analysis and exclusion of implausible scenarios.”

HD1 is extremely bright in ultraviolet light. To explain this, “some energetic processes are occurring there or, better yet, did occur some billions of years ago,” Pacucci says.

At first, the researchers assumed HD1 was a standard starburst galaxy, a galaxy that is creating stars at a high rate. But after calculating how many stars HD1 was producing, they obtained “an incredible rate—HD1 would be forming more than 100 stars every single year. This is at least 10 times higher than what we expect for these galaxies.”

That’s when the team began suspecting that HD1 might not be forming normal, everyday stars.

“The very first population of stars that formed in the universe were more massive, more luminous and hotter than modern stars,” Pacucci says. “If we assume the stars produced in HD1 are these first, or Population III, stars, then its properties could be explained more easily. In fact, Population III stars are capable of producing more UV light than normal stars, which could clarify the extreme ultraviolet luminosity of HD1.”

Scientists have spotted the farthest galaxy ever
Timeline displays the earliest galaxy candidates and the history of the universe. Credit: Harikane et al., NASA, EST and P. Oesch/Yale.

A supermassive black hole, however, could also explain the extreme luminosity of HD1. As it gobbles down enormous amounts of gas, high energy photons may be emitted by the region around the black hole.

If that’s the case, it would be by far the earliest supermassive black hole known to humankind, observed much closer in time to the Big Bang compared to the current record-holder.

“HD1 would represent a giant baby in the delivery room of the early universe,” says Avi Loeb an astronomer at the Center for Astrophysics and co-author on the MNRAS study. “It breaks the highest quasar redshift on record by almost a factor of two, a remarkable feat.”

HD1 was discovered after more than 1,200 hours of observing time with the Subaru Telescope, VISTA Telescope, UK Infrared Telescope and Spitzer Space Telescope.

“It was very hard work to find HD1 out of more than 700,000 objects,” says Yuichi Harikane, an astronomer at the University of Tokyo who discovered the galaxy. “HD1’s red color matched the expected characteristics of a galaxy 13.5 billion light-years away surprisingly well, giving me a little bit of goosebumps when I found it.”

The team then conducted follow-up observations using the Atacama Large Millimeter/submillimeter Array (ALMA) to confirm the distance, which is 100 million light years further than GN-z11, the current record-holder for the furthest galaxy.

Using the James Webb Space Telescope, the research team will soon once again observe HD1 to verify its distance from Earth. If current calculations prove correct, HD1 will be the most distant—and oldest—galaxy ever recorded.

The same observations will allow the team to dig deeper into HD1’s identity and confirm if one of their theories is correct.

“Forming a few hundred million years after the Big Bang, a black hole in HD1 must have grown out of a massive seed at an unprecedented rate,” Loeb says. “Once again, nature appears to be more imaginative than we are.”

More information: A Search for H-Dropout Lyman Break Galaxies at z~12-16, arXiv:2112.09141 [astro-ph.GA] arxiv.org/abs/2112.09141 , Accepted for publication in MNRAS Letters.
Are the newly-discovered z∼13 drop-out sources starburst galaxies or quasars?, arXiv:2201.00823 [astro-ph.GA] arxiv.org/abs/2201.00823 , Accepted for publication in ApJ.

Journal information: Astrophysical Journal , Monthly Notices of the Royal Astronomical Society Letters , Monthly Notices of the Royal Astronomical Society
Provided by Harvard-Smithsonian Center for Astrophysics

New fossil from Brazil hints at the origins of the mysterious tanystropheid reptiles

A new species of Triassic reptile from Brazil is a close cousin of a mysterious group called tanystropheids, according to a study published April 8, 2020 in the open-access journal PLOS ONE by Tiane De-Oliviera of the Federal University of Santa Maria, Brazil and colleagues.

After the Permian mass extinction, 250 million years ago, reptiles took over global ecosystems. Among the early groups to appear after this extinction event were the tanystropheids, a group of long-necked animals whose lifestyles are still mysterious, but who were nonetheless successful in the Triassic Period. However, the early evolution of this group is poorly understood, as their remains are very rare from the Early Triassic.

In this study, De-Oliviera and colleagues describe a new specimen of reptile from Early Triassic rocks of the Sanga do Cabral Formation in southern Brazil. Skeletal comparison indicates this specimen, known from remains of the hind leg, pelvis, and tail, is the closest known relative of tanystropheids. The researchers identified these remains as belonging to a new species, which they named Elessaurus gondwanoccidens. The name derives in part from the Elvish name (Elessar) of a character from Lord of the Rings also known as Aragorn or Strider, chosen as a reference to the fossil animal’s long legs.

Most tanystropheid fossils are found in Middle to Late Triassic rocks of Europe, Asia, and North America, and often in marine sediments. The presence of Elessaurus in continental deposits of Early Triassic South America suggests that the origins of this group may lie in the southern continents, and that their ancestors may have lived on land before later species adapted to aquatic life. A clearer view of the group’s origins will rely on more rare fossils from this early time in their evolution.

More information: De-Oliveira TM, Pinheiro FL, Stock Da-Rosa ÁA, Dias-Da-Silva S, Kerber L (2020) A new archosauromorph from South America provides insights on the early diversification of tanystropheids. PLoS ONE 15(4): e0230890. doi.org/10.1371/journal.pone.0230890
Journal information: PLoS ONE
Provided by Public Library of Science

A new basal ichthyosauromorph from the Lower Triassic (Olenekian) of Zhebao, Guangxi Province, South China

Ichthyosaurs are a group of successful Mesozoic marine reptiles that have a worldwide distribution, but their evolutionary origin is still unclear. In recent years, many new marine reptiles related to ichthyosaurs, and called early ichthyosauromorphs, have been found in rocks of the Early Triassic age and shed light on the origin of ichthyosaurs.

These early ichthyosauromorphs have been discovered in many countries, but most of them are from China, including Cartorhynchus, Chaohusaurus, and several members of an ichthyosauromorph subgroup called the Hupehsuchia. They are generally small (about 1m long) and are from the eastern and central regions of China. In a new paper published in the journal PeerJ, researchers from China and Canada report on a new large early ichthyosauromorph, named Baisesaurus robustus, from the southwest of China, extending the known geographic distribution of this group.

In 2017, Guizhou Geological Survey field crews found some vertebrate bones exposed in limestone in the Zhebao region of Guangxi Province, southwest China, and they invited researchers (Haishui Jiang and Fenglu Han) from China University of Geosciences (Wuhan) to join them in studying the specimen. Jiang and Han confirmed that the fossil was that of a marine reptile, possibly a relative of ichthyosaurs. The specimen was collected by the joint research team in 2018, and was prepared in the Wuhan Centre of the China Geological Survey.

The specimen comprises only the front part of the trunk skeleton, including some vertebrae and ribs, a limb bone, and abdominal bones called gastralia. This made classification difficult, but the researchers compared the fossil comprehensively with other marine reptiles from the Early Triassic and ultimately identified it as an ichthyosauromorph. “The dorsal ribs and gastralia are more similar to those of other early ichthyosauromorphs, such as Chaohusaurus, than to sauropterygians,” said Long Cheng, a coauthor on the study.

A new basal ichthyosauromorph from the Lower Triassic (Olenekian) of Zhebao, Guangxi Province, South China
Field workers prepare to use an electric power saw to extract the block containing the fossil specimen. Credit: Jicheng Ren et al. PeerJ (2022). DOI: 10.7717/peerj.13209

In general, Baisesaurus robustus shares more similarities with Utatsusaurus from Japan, another early ichthyosauromorph, than with other marine reptiles. The researchers also found some unusual features that were unknown in other early ichthyosauromorphs, such as deep depressions on the sides of the vertebrae, and a robust radius with two distinct joint facets for contact with wrist bones.

These new features indicate that the fossil belongs to a previously unknown species, which the researchers named Baisesaurus robustus. Moreover, Baisesaurus is estimated to have been about 3 m long, making this newly discovered marine reptile significantly larger than any other Early Triassic ichthyosauromorph from China. Finally, Baisesaurus has a more robust radius than many other early ichthyosauromorphs, suggesting strong swimming abilities that might have been used for long-distance migrations along the eastern margin of an ancient ocean known as the Paleo-Tethys.

A new basal ichthyosauromorph from the Lower Triassic (Olenekian) of Zhebao, Guangxi Province, South China
The new specimen of Baisesaurus following preparation in a lab. Credit: Jicheng Ren et al. PeerJ (2022). DOI: 10.7717/peerj.13209

“I’m inclined to take Baisesaurus as a reminder that there’s still a lot to be discovered about the tremendous evolutionary explosion of vertebrate diversity that took place in the Triassic,” said Corwin Sullivan, a coauthor on the study. Sullivan is an associate professor at the University of Alberta in Edmonton, Canada, and curator of the Philip J. Currie Dinosaur Museum in nearby Wembley.

More information: Jicheng Ren et al, A new basal ichthyosauromorph from the Lower Triassic (Olenekian) of Zhebao, Guangxi Autonomous Region, South China, PeerJ (2022). DOI: 10.7717/peerj.13209
Journal information: PeerJ
Provided by PeerJ

Paleontology: ‘Big John’ provides evidence of triceratops combat injuries

The fossilized remains of the triceratops specimen known as “Big John” display injuries to the skull that may have occurred during combat with another triceratops, according to new research published in Scientific Reports.

Triceratops (Triceratops horridus) is a species of horned dinosaurs characterized by its large neck frill formed from extended patietal and squamosal skull bones. It has been suggested that this bony frill served as protection against injuries from other triceratops during fights.

Ruggero D’Anastasio and colleagues examined the triceratops specimen known as “Big John,” so named for its large size, which was discovered in 2014 in the Upper Cretaceous Hell Creek Formation, Montana, USA. They report the presence of a keyhole-shaped opening (a fenestra) in the right squamosal bone. The bone surface around the fenestra is irregular and features plaque-like deposits of bone, which could have resulted from inflammation (possibly from infection).

The authors analyzed samples taken from the larger margin of the fenestra, which reveal that the bone tissue around the fenestra is porous with lots of blood vessels compared to bone tissue further from the fenestra, suggesting that this was newly formed bone. The bone also showed signs of remodeling, as demonstrated by the presence of little pits known as Howship lacunae.

Together, these features indicate that the fenestra was caused by a traumatic injury but that the bone was healing at the time of Big John’s death. The authors suggest that the injury was caused by the horn of another triceratops, and occurred at least six months before Big John’s death. Based on these findings, the mechanisms underlying the healing process in dinosaurs appears to be similar to that in mammals.

More information: Ruggero D’Anastasio, Histological and chemical diagnosis of a combat lesion in Triceratops, Scientific Reports (2022). DOI: 10.1038/s41598-022-08033-2. www.nature.com/articles/s41598-022-08033-2
Journal information: Scientific Reports

Forecasters predict another active hurricane season with 19 tropical storms, 9 hurricanes

After two of the most active hurricane seasons on record in 2020 and 2021, top hurricane forecasters on Thursday said we should expect another above-normal season this year.

For the season, which begins June 1, meteorologist Phil Klotzbach and other experts from Colorado State University—among the nation’s top seasonal hurricane forecasters—predict 19 named tropical storms will form in 2022, of which 9 will become hurricanes.

An average season has 14 tropical storms, seven of which become hurricanes. If the prediction holds true, it will be the seventh consecutive above-normal season.

A tropical storm becomes a hurricane when its wind speed reaches 74 mph.

Of the nine predicted hurricanes, four are expected to spin into major hurricanes—Category 3, 4 or 5—with sustained wind speeds of 111 mph or greater. The group said there’s a 71% chance at least one major hurricane will make landfall somewhere in the U.S.

The Atlantic hurricane season runs from June 1 to Nov. 30, though storms sometimes form outside those dates. In fact, storms have formed in May in each of the past seven years.

According to Klotzbach, the reasons for the above-average forecast include the predicted lack of El Niño and warmer-than-normal seawater in the subtropical Atlantic Ocean.

One of the major determining factors in hurricane forecasting is whether we are in an El Niño or La Niña climate pattern.

El Niño is a natural warming of tropical Pacific Ocean water, which tends to suppress the development of Atlantic hurricanes. Its opposite, La Niña, marked by cooler ocean water, tends to increase hurricanes in the Atlantic.

El Niño generally increases vertical wind shear in the Atlantic, which can tear apart developing hurricanes.

Insurance companies, emergency managers and news outlets use these seasonal forecasts to prepare Americans for the year’s hurricane threat. The team’s annual predictions provide the best estimate of activity during the upcoming season, not an exact measure, according to Colorado State.

The university, under the direction of meteorologist William Gray, was the first group to predict seasonal hurricane activity in the mid-1980s. Gray died in 2016.

This is the team’s 39th forecast. It covers the Atlantic basin, which includes the Caribbean Sea and the Gulf of Mexico.

Federal forecasters from the National Oceanic and Atmospheric Administration will issue their prediction for the season in May.

Climate change is making Afghanistan’s hunger crisis worse

Drought had already devastated Allawddin Rahimi’s wheat fields when the Taliban reached his village in northern Afghanistan. The group’s takeover left him with no choice but to flee.

“I wasn’t worried about the Taliban return as much as I was worried about the drought that dried up our only revenue and source of food,” Rahimi, 37, said from the port city of Bandar Abbas in neighboring Iran, where he arrived in November to search for a job. He now earns about $3.50 a day as a laborer on a construction site, which he sends home to support a family of seven in Afghanistan’s Balkh province.

As the planet warms, the worst dry spell in two decades has coincided with Afghanistan’s political and economic upheaval. Climate change is expected to have severe effects on the country over the coming decades, with the ousted Afghan government and the United Nations projecting extreme temperature rises of more than 6 degrees Celsius if global carbon emissions are left unchecked. Already one of the world’s poorest countries, its economy’s dislocation from billions of dollars in aid leaves Afghanistan more ill-equipped than ever to confront the challenges of global warming and reduced rainfall.

The fallout from the Taliban’s takeover, coupled with the drought and soaring wheat prices thanks to Russia’s war with Ukraine, means that some 10 million people—more than a quarter of Afghanistan’s population—are near famine. For the first time, city residents are as vulnerable to starvation as rural citizens who rely on local crops for income and sustenance, according to the Afghan Analysts Network, a research organization in Kabul.

“The overarching drivers on top of a whole lot of other things are the drought and the economic crisis,” Mary Ellen McGroarty, country director for the U.N. World Food Program, said in an interview from Kabul. “They’re just wiping away the coping mechanisms that households would normally have.”

It’s not just rural farmers who are suffering. Sayed Ehsan was once a teacher in Mazar-i-Sharif, the capital of Balkh. After the Taliban closed his school for months, he borrowed $5,000 from a relative and sold his wife’s jewels for around $1,000 to buy a taxi. He makes about $100 a month.

He and his wife regularly have foodless days. They make sure that their four children, ranging from 4 to 7 years old, eat once or twice a day. Meals often consist of bread and green tea, rather than the traditional local dish of pilaf, made with rice, raisins, almonds and lamb, that they used to eat regularly. The best meal they can look forward to now is a bowl of soup with a piece of meat.

“There is no other option,” Ehsan said in a telephone interview. “The only thing that matters now is that we survive and eat. We’re like wild animals in a jungle fighting for a slice of bread. That is the current state of Afghanistan.”

Ehsan says that he’s heard of people selling their infant daughters for between 15,000 ($170) and 20,000 afghanis in order to pay for food. “It’s alarming for everyone, and it explains why the country’s hunger crisis is so severe,” he said.

In Rahimi’s village of Qarchi Gak, very low levels of moisture in the soil and inadequate rainfall presage a poor harvest, according to Andy Hoell, a research meteorologist at the U.S. government’s National Oceanic and Atmospheric Administration’s physical-sciences laboratory.

Snow and rainfall will be crucial to Afghanistan’s ability to recover from 2021’s drought, which was driven by a massive drop in water melting off the nearby Hindu Kush mountains. Meteorologists warn that the La Niña weather pattern in the Pacific Ocean threatens to prolong the drought at least until the end of the year. The increasing risk of extreme weather events also raises the prospect of prolonged water scarcity in the country’s rural areas, according to the World Meteorological Organization.

The timing of last year’s La Niña couldn’t have been worse. As the Taliban made advances and U.S. troops began to withdraw, warmer weather intensified, according to the Famine Early Warning Systems Network, a U.S. government-backed website that provides information and data about food-insecure countries. The fundamentalist Islamist group swept to power in August 2021, emboldened by the chaotic U.S. withdrawal from the country after its 20-year war.

Afghanistan’s wheat yield dropped 30% during last year’s harvest, according to Mohammad Assem Mayar, a former lecturer of water resources management at the Kabul Polytechnic University of Afghanistan and guest author on climate change for the Afghan Analysts Network. Mayar and other experts fear the 2021 drought will continue this year as rainfall drops below average levels in the coming months.

“Wheat is the backbone of Afghanistan livelihoods,” said Richard Trenchard, the United Nations Food and Agriculture Organization’s representative in Afghanistan. More than 70% of farmland—much of it lacking in water—is used to grow the crop. Meanwhile U.S. sanctions have cut off much of the country’s banking sector and left its central bank struggling to fund imports of essential goods, including food.

McGroarty, from the World Food Program, has urged the U.S. and other countries imposing sanctions on Afghanistan’s economy to preserve access to essential supplies like food. The U.S. has said it won’t block humanitarian imports but a decision last month to seize half the Central Bank of Afghanistan’s assets to pay victims of the Sept. 11 attacks has prompted wide criticism.

With no signs of policy changing, how the weather turns out this year could decide who gets to eat. “We’re all looking at the snowfall. That’s going to be critical,” McGroarty said.

Afghanistan has seen massive displacement as people fled to urban centers or across its borders. The west and north, where Rahimi used to farm, are among the worst affected areas, according to the Famine Early Warning Systems Network.

Those who arrive in cities often have to rely on handouts from organizations such as the WFP. In Kabul and throughout Afghanistan, many marketplaces brim with food, but few can afford to purchase it. Costs have increased more than 50% since the Taliban took power and many have lost their jobs. Acute malnutrition is above emergency levels in 25 out of the country’s 34 provinces is is expected to worse, according to the WFP.

“We have bags of flour and rice, as well as cooking oil and whatever else you would require, but no one is coming over to buy them,” Ghulam Qader, a shopkeeper in Kabul’s main food market, said in a telephone interview. He is able to sell some food by lowering prices slightly, but most of the leftovers end up spoiled or thrown away. There are only two or three customers per day, compared with as many as 15 last year.

Mahmood Siddiqi, a 42-year-old economics lecturer at a university in Kabul, has to rely on the WFP to feed his family. The Siddiqi family has survived decades of conflict and civil war, but this is the first time they’re facing hunger and malnutrition. “People are only concerned about food. From the poor to the middle class, everyone is suffering every day,” Siddiqi said.

Siddiqi was employed at a private university in Kabul until it collapsed after female students stopped attending because of the Taliban’s ban on women’s education. He sold his television, computer and smartphone to help his family survive until he was able to get help from the WFP.

That involved obtaining a special card—via biometric checks and approval from a government-appointed local elder—that qualifies his family for food handouts. It’s a monthly ration consisting of 50 kilograms of flour, 5 liters of cooking oil and 7 kilograms of beans, which he’s been promised over the course of six months, beginning in December.

“Without their support, we would perish within days,” Siddiqi said.

Months before the Taliban took power, the former government’s National Water Affairs Regulation Authority had announced plans to build 44 dams to help improve agriculture. The future of those projects, along with scores of others related to water and irrigation, is now unclear.

The Taliban says it’s already started work on Afghanistan’s “biggest ever canal project” to irrigate more than 580,000 hectares of farmland in the country’s north by diverting water from the Amu Darya river, which demarcates a section of the border with Uzbekistan. The group’s deputy spokesman Bilal Karimi said the Qosh Tepa canal project kicked off on March 30 and is expected to cost some 60 billion afghanis and create 200,000 jobs. Funding will come from the Taliban’s “own revenue sources,” Karimi said, without giving further details.

No matter what happens with the project, the regime will have to carefully manage water resources to ensure food security in the future, according to Mayar. Ideally, that would include building and modernizing dams to increase national water storage capacity, which is currently 10 times lower than Afghanistan’s neighbors, Mayar said. Most current structures predate the Soviet Union’s 1979 invasion and Afghanistan’s subsequent four decades of almost uninterrupted conflict. After the U.S. invasion in 2001, dams funded by the U.S. and its NATO coalition were frequently targeted by the Taliban.

Iran, which shares a long border with the country, has also accused the government of now-ousted President Ashraf Ghani of breaking a 1973 treaty over access to the Helmand River’s water. Last month, Iranian state media reported that officials were in talks with the Taliban over the management of flows into Iran’s Sistan-Baluchestan province, where farmers have been protesting water scarcity and parched conditions.

“Some of these water issues are bad now, but could get abruptly worse,” said Graeme Smith, senior consultant at the Washington-based International Crisis Group.

How bad the crisis gets depends heavily on the international community’s response to the Taliban, given that it’s listed as a terrorist group by the U.S., European Union and most of their allies. Washington has said it will release $3.5 billion to organizations such as the U.N. that are working on the ground.

According to McGroarty, who’s managing the U.N.’s response in the country, the WFP is already facing a shortfall of around $1.9 billion of the $2.6 billion needed this year to deliver food to 23 million people. Her team has reduced daily food baskets to as little as 50% of the full 2,100 calories that are normally provisioned per person.

“I’m terrified for the people getting across this winter and I hope we are able to do enough in time to be able to save lives and give people some succor, some comfort,” McGroarty said.

A landslide near a glacier caused a tsunami. Was there a climate connection?

In 2020, seismologist Goran Ekström noticed a peculiar wiggle picked up on Nov. 28 by seismographs around the world. It emanated from a remote area in British Columbia’s steep, glaciated Central Coast Mountains, some 2,400 miles from Ekström’s office at Columbia University’s Lamont-Doherty Earth Observatory, in Palisades, N.Y.

“When I find something [that] looks a bit strange, I look at it more carefully,” said Ekström, who studies unusual seismic events. Conventional earthquakes usually begin with a big, high-frequency jolt, but this was not the case here. This was more of a low-frequency rumble that gradually accelerated before fading back—according to Ekström’s studies, the kind of signal produced by a big landslide. He emailed Marten Geertsema, a natural-hazards specialist with the BC provincial government. Seeing nothing in the news, Geertsema proceeded to scan recent satellite imagery of the area for signs of a disturbance, but couldn’t spot anything at first.

Around the same time, BC aviators heard about an unusual amount of wood floating in a fjord. They helicoptered in. Flying further up a river feeding the fjord, they saw countless mowed-down trees and a vast new wasteland of sand and gravel. Tracing up a side valley occupied by a stream called Elliot Creek, they found the source: the fresh scar of a gigantic landslide. It had hit a meltwater lake at the toe of the West Grenville Glacier and created a tsunami that devastated everything downstream. The scientists quickly connected the dots.

In a new paper in the journal Geophysical Research Letters, Geertsema, Ekström and colleagues describe the slide’s magnitude and effects, along with its possible causes—which include the rapid recession of the West Grenville Glacier, which has retreated some 4 kilometers from its mid-19th century position. It is only the latest such occurrence in a warming world where mountain glaciers are rapidly pulling back and creating conditions ripe for such collapses. The paper is accompanied by a spectacular visual interactive feature from the Hakai Institute, several of whose researchers contributed to the report.

Since 1900, there have been at least 1,000 known so-called glacial outburst floods worldwide. They have killed at least 12,500 people and devastated dams, towns, farms and wildlife habitat. Many occur in steep areas of the Himalayas; mountainous British Columbia and Southeast Alaska also are hot spots. While the causes can be complex, fast glacial retreat is a suspect in many cases. As ice pulls back through narrow ice-carved valleys, steep rock walls formerly held back by the ice are left fractured and barely hanging together. Often, a meltwater lake forms at the glacier’s toe. Time, precipitation, frost action and gravity do the rest. As a result, many scientists believe that landslides and resulting floods will increase as climate warms, if they are not already be doing so.

The new paper is one of the most complete analyses of a glacial outburst flood to date. The authors, from more than a dozen universities, government agencies and private research institutes, and the local Homalco and Xwe’malkwhu First Nations, used laser mapping, satellite imagery, seismic data and state-of-the-art computer simulations to model what happened.

They concluded that some 50 million tons of rock—about the mass of all the automobiles in Canada—plummeted 1,000 meters down the valley wall into an unnamed meltwater lake at the glacier’s toe, and into the glacier itself. They say that some of the ice was probably instantly liquefied. Displaced water and sediment spurted up some 100 meters, then rushed in a wave down the 10-kilometer-long Elliot Creek valley at about 135 kilometers (84 miles) per hour, scouring out trees and soil. When it hit the adjoining Southgate River, debris piled up in a giant fan; floodwater and debris continued through the river to form a sediment plume more than 60 kilometers long in the downstream fjord.

No humans were killed, but the outburst destroyed large swaths of forest and salmon spawning habitat in the traditional lands of the Homalco people. Fisheries scientists think hundreds of thousands or even millions of fish were killed outright, and continuing turbidity in the watershed may be compromising fish survival. A logging camp with more than a dozen vehicles was wiped out, and fuel and hydraulic fluid continue to leak from the remains. There could be long-term effects on bears and eagles, who depend on the salmon, as do the native people.

The paper says the immediate trigger for the slide is unknown, but factors leading up to it “include fractured bedrock with favorably oriented joints and debuttressing of the base of the slope due to glacier retreat.” They characterize the event as “an example of a sometimes underappreciated hazard chain in high mountains undergoing rapid deglaciation. [Rapid] retreat may increase the hazards of these events as the number and size of lakes increase below potentially unstable slopes in alpine valleys.”

Ekström and his onetime Lamont-Doherty colleague Colin Stark began studying the possibility of detecting landslides using seismic signals around 2009. They have since documented more than 50 big events. The Elliot Creek slide is not even the biggest. In 2015, they detected the collapse of 200 million tons of rock at the base of Alaska’s Tyndall Glacier, under similar conditions. The following year, they detected a 120 million-ton collapse in Alaska’s Glacier Bay National Park.

With the hazard probably growing, scientists are looking into employing seismic instruments in real time to help authorities issue tsunami warnings and search for victims. For example, a 2020 study led by Lamont-Doherty scientists looked at a 1994 slide detected by seismic instruments hours before a subsequent tsunami reached a village in Bhutan, killing 21 people. If the instruments had been hooked to an early-warning system, people could have escaped. “This is a striking and scary reminder that [outburst floods] starting at these high altitudes pick up their devastating energy by gravity on their way downhill,” said Joerg Schaefer, one of the study’s authors.

The researchers in the new paper say that the close agreement between their physical modeling and the field evidence they gathered could be adapted to help predict future outbursts. “Fortunately, these and similar events in Western Canada have occurred in remote mountain valleys,” they write. “However, there is no assurance that this will be true in the future, given increased development and tourism in these remote areas.”

More information: M. Geertsema et al, The 28 November 2020 Landslide, Tsunami, and Outburst Flood—A Hazard Cascade Associated With Rapid Deglaciation at Elliot Creek, British Columbia, Canada, Geophysical Research Letters (2022). DOI: 10.1029/2021GL096716
Journal information: Geophysical Research Letters

Surfer science supports seawater study

Seawater samples taken from a surfboard have helped scientists understand microscopic life in the waves, new research shows.

Phytoplankton are at the base of ocean food chains, and nearshore waters like the “surf zone” often contain the highest levels of these tiny organisms.

However, sampling water in the surf zone is difficult, so data on some aspects of this environment is scarce.

Dr. Bob Brewin—a surfer and scientist from the University of Exeter—took to the waves to collect water samples to analyze seasonal changes in phytoplankton.

And the research team—led by Exeter and Plymouth Marine Laboratory—are working to gather more data from surfers, swimmers, kayakers and others who use nearshore waters.

“Nearshore waters often have the highest levels of biodiversity in the ocean,” said Dr. Brewin, of Exeter’s Penryn Campus in Cornwall.

“Phytoplankton are a very important component of that, but at present we struggle to monitor seasonal and longer-term changes in nearshore phytoplankton concentrations.”

“It’s hard to take research vessels or build monitoring stations in places where waves are constantly breaking, and this leaves key gaps in our knowledge.”

The new study, based 67 samples taken by Dr. Brewin off Bovisand Beach near Plymouth (UK) in a 12-month period, is intended as a pilot to see if this citizen-science approach could be used more widely.

The samples were tested for chlorophyll-a concentration (a proxy of phytoplankton biomass) and compared with data from a recording station about four miles offshore.

The results suggest phytoplankton levels nearshore and offshore are similar in autumn, winter and spring.

However, in July and August phytoplankton biomass was much higher in nearshore waters than offshore—where levels dropped dramatically.

Dr. Brewin said the likely cause of this is that the spring bloom of phytoplankton in offshore waters depletes chemical nutrients, and these relatively stable waters don’t churn enough over the summer to replenish them.

Meanwhile, the constant motion of waves near the shore stirs up nutrients, and together with nutrients from river run-off, this allows phytoplankton to continue blooming.

Dr. Brewin said more research is needed to test and confirm this hypothesis, and to investigate the possible impacts of climate change in nearshore waters.

“The timing and distribution of these blooms is critical for how energy moves up the food web,” he said.

“For example, fish larvae need that phytoplankton to feed—if the timing is just a little bit off, that can be devastating for the growth of the larvae.”

Speaking about the use of surfers and other ocean users as citizen scientists, he added: “If we start now, in 20 or 30 years we could have a really good understating of how climate change is impacting the nearshore environment.”

Lead author Elliot McCluskey said that “Surfers and other water sports enthusiasts are regularly going in and out the ocean for fun, all around the world.”

“Many have an intrinsic desire to protect the regions they inhabit. Our work suggests they could to that by helping to understand the cycles of life in the ocean.”

The research team included the University of California, the University of North Carolina Wilmington and Nova Southeastern University.

The paper is published in the journal Oceans.

More information: Elliot McCluskey et al, On the Seasonal Dynamics of Phytoplankton Chlorophyll-a Concentration in Nearshore and Offshore Waters of Plymouth, in the English Channel: Enlisting the Help of a Surfer, Oceans (2022). DOI: 10.3390/oceans3020011

Megathrust earthquake and tsunami 3,800 years ago kept hunter-gathers in Chile inland for 1,000 years

An international team of researchers has found evidence of a megathrust earthquake occurring approximately 3,800 years ago off the coast of what is now Chile. In their paper published in the journal Science Advances, the team describes evidence they found of the ensuing tsunami and its impact on the people who lived in the area at the time.

In 1966, a massive earthquake shook the ground in southern Chile. Seismographs showed it to be 9.5 on the Richter scale—the strongest earthquake in recorded history. In this new effort, the researchers have found evidence of an equally strong earthquake occurring in roughly the same area approximately 3,800 years ago—one that set off a massive tsunami that wreaked havoc on the early hunter-gatherers who were living along the coast.

The work by the researchers involved digging through layers of dirt in the Atacama Desert looking for sediment left behind by the tsunami. Radiocarbon dating of shells and charcoal fragments in the sediment showed it to be from approximately 3,800 years ago. The tsunami was so big it left a trail of debris for 1,000 miles and likely pushed seawater up to 15 to 20 meters above sea level.

Chile’s coast lies on a subduction zone—the Nazca oceanic plate is slowly being pushed under the South American continental plate, and because of that, the area has a lot of earthquakes. Sometimes they are really big ones, which are called megathrust earthquakes. Plate activity is also responsible for the creation of the Andes mountains and its volcanic activity.

The researchers also found evidence of shifts in population centers following the tsunami—people moved inland and to higher ground. Evidence was also found of people moving their burial grounds. The researchers found that the people did not start returning to the shore for over a thousand years and even then, they appeared to be hesitant to move too close to the sea. Researchers note that they have not found evidence of how the memory of the tsunami could have persisted for so long in a people who did not have a written language. They also suggest that their work could contribute to safety plans for the people who live in the area today.

Hubble probes extreme weather on ultra-hot Jupiters

In studying a unique class of ultra-hot exoplanets, NASA Hubble Space Telescope astronomers may be in the mood for dancing to the Calypso party song “Hot, Hot, Hot.” That’s because these bloated Jupiter-sized worlds are so precariously close to their parent star they are being roasted at seething temperatures above 3,000 degrees Fahrenheit. That’s hot enough to vaporize most metals, including titanium. They have the hottest planetary atmospheres ever seen.

In two new papers, teams of Hubble astronomers are reporting on bizarre weather conditions on these sizzling worlds. It’s raining vaporized rock on one planet, and another one has its upper atmosphere getting hotter rather than cooler because it is being “sunburned” by intense ultraviolet (UV) radiation from its star.

This research goes beyond simply finding weird and quirky planet atmospheres. Studying extreme weather gives astronomers better insights into the diversity, complexity, and exotic chemistry taking place in far-flung worlds across our galaxy.

“We still don’t have a good understanding of weather in different planetary environments,” said David Sing of the Johns Hopkins University in Baltimore, Maryland, co-author on two studies being reported. “When you look at Earth, all our weather predictions are still finely tuned to what we can measure. But when you go to a distant exoplanet, you have limited predictive powers because you haven’t built a general theory about how everything in an atmosphere goes together and responds to extreme conditions. Even though you know the basic chemistry and physics, you don’t know how it’s going to manifest in complex ways.”

In a paper in the April 6 journal Nature, astronomers describe Hubble observations of WASP-178b, located about 1,300 light-years away. On the daytime side the atmosphere is cloudless, and is enriched in silicon monoxide gas. Because one side of the planet permanently faces its star, the torrid atmosphere whips around to the nighttime side at super-hurricane speeds exceeding 2,000 miles per hour. On the dark side, the silicon monoxide may cool enough to condense into rock that rains out of clouds, but even at dawn and dusk, the planet is hot enough to vaporize rock. “We knew we had seen something really interesting with this silicon monoxide feature,” said Josh Lothringer of the Utah Valley University in Orem, Utah.

In a paper published in the January 24 issue of Astrophysical Journal Letters, Guangwei Fu of the University of Maryland, College Park, reported on a super-hot Jupiter, KELT-20b, located about 400 light-years away. On this planet a blast of ultraviolet light from its parent star is creating a thermal layer in the atmosphere, much like Earth’s stratosphere. “Until now we never knew how the host star affected a planet’s atmosphere directly. There have been lots of theories, but now we have the first observational data,” Fu said.

By comparison, on Earth, ozone in the atmosphere absorbs UV light and raises temperatures in a layer between 7 to 31 miles above Earth’s surface. On KELT-20b the UV radiation from the star is heating metals in the atmosphere which makes for a very strong thermal inversion layer.

Evidence came from Hubble’s detection of water in near-infrared observations, and from NASA’s Spitzer Space Telescope’s detection of carbon monoxide. They radiate through the hot, transparent upper atmosphere that is produced by the inversion layer. This signature is unique from what astronomers see in the atmospheres of hot-Jupiters orbiting cooler stars, like our Sun. “The emission spectrum for KELT-20b is quite different from other hot-Jupiters,” said Fu. “This is compelling evidence that planets don’t live in isolation but are affected by their host star.”

Though super-hot Jupiters are uninhabitable, this kind of research helps pave the way to better understanding the atmospheres of potentially inhabitable terrestrial planets. “If we can’t figure out what’s happening on super-hot Jupiters where we have reliable solid observational data, we’re not going to have a chance to figure out what’s happening in weaker spectra from observing terrestrial exoplanets,” said Lothringer. “This is a test of our techniques that allows us to build a general understanding of physical properties such as cloud formation and atmospheric structure.”

More information: Joshua Lothringer, UV absorption by silicate cloud precursors in ultra-hot Jupiter WASP-178b, Nature (2022). DOI: 10.1038/s41586-022-04453-2. www.nature.com/articles/s41586-022-04453-2
Guangwei Fu et al, Strong H2O and CO Emission Features in the Spectrum of KELT-20b Driven by Stellar UV Irradiation, The Astrophysical Journal Letters (2022). DOI: 10.3847/2041-8213/ac4968

Journal information: Astrophysical Journal Letters , Nature

Provided by ESA/Hubble Information Centre.