It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Friday, May 12, 2023
Great Basin: History of water supply in one of the driest regions in the USA
An international team including Simon Steidle from the Quaternary Research Group at the Department of Geology at the University of Innsbruck has reconstructed the evolution of groundwater in the Great Basin, USA up up to 350,000 years into the past.
IMAGE: THE INNSBRUCK GEOLOGY TEAM HAS BEEN CARRYING OUT INVESTIGATIONS IN DEVILS HOLE FOR YEARS, HERE DESCENDING INTO THE CAVE TO TAKE DRILL CORES UNDER WATER.view more
CREDIT: ROBBIE SHONE
The team led by Christoph Spötl has been investigating the famous "Devils Hole" cave system in Nevada since 2010 - during spectacular expeditions. Using the calcite deposits in the cave, the researchers have already reconstructed the development of the water level in the cave up to several hundred thousand years ago. In the current study, this information has now been combined with a numerical groundwater model for this arid region. "Based on our extensive sampling in Devils Hole, we have a large amount of data that provides information on the evolution of the water table. By combining this with groundwater models from the US Geological Survey, we can now draw quantitative conclusions about changes in precipitation for the entire region over the last 350,000 years using the precise data from the cave," explains the geologist Simon Steidle. In drylands like the southwest of the USA, precipitation is particularly important and groundwater data is a mirror of changes in the hydroclimate. "The results can be useful for developing water management strategies and sustainable use of groundwater resources, such as how much water can be withdrawn for agricultural purposes."
Drought increases sensitivity
The new data suggest that the elevation of the water table in Devils Hole was three to four times more sensitive to groundwater recharge during dry climates than during wetter climates of the past. "Given that drought conditions will likely increase even more in the future due to the ongoing climate crisis, our results highlight the vulnerability of large aquifers, and thus the alteration of the most important freshwater resource in this area of the United States," Steidle said. The minimum groundwater level in Devils Hole during the peak of the interglacial warm periods was no more than 1.6 metres below today's level, which corresponds to a decrease in groundwater recharge of less than 17 % compared to today's conditions. During the glacial periods, however, the level was at least 9.5 metres above today's level, which means an increase in groundwater recharge of almost 250% compared to today's conditions. The new information is relevant especially for the already highly endangered Devils Hole pupfish, a fish measuring just a few centimetres whose only habitat is the water in Devils Hole. The habitat of this species is thus the smallest of all known vertebrates (about half the size of an average classroom). Even small changes in water availability triggered by abstraction of groundwater for irrigation purposes or by climate change are of utmost importance for its survival.
Using an underwater drill specially developed for the expedition to Devils Hole, the researchers took samples from the calcite deposits in the cave.
CREDIT
Robbie Shone
Publication: A 350,000-year history of groundwater recharge in the southern Great Basin, USA: Tracie R. Jackson, Simon D. Steidle, Kathleen A. Wendt, Yuri Dublyansky, R. Lawrence Edwards & Christoph Spötl. Communications Earth & Environment, 4:98 (2023), https://doi.org/10.1038/s43247-023-00762-0
IMAGE: BENJAMIN WATERHOUSE HAWKIN'S CONCEPTUAL DRAWING OF THE PALEOZOIC MUSEUM.view more
CREDIT: ANNUAL REPORT OF THE BOARD OF COMMISSIONERS OF THE CENTRAL PARK (1858)
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.”
The article
‘The curious case of Central Park's dinosaurs: The destruction of Benjamin Waterhouse Hawkins' Paleozoic Museum revisited’ By Victoria Coules and Michael J. Benton. Proceedings of the Geologists’ Associationonline Link.
Benjamin Waterhouse Hawkins' studio at the Central Park Arsenal, with models of extinct animals.
CREDIT
Published in The 12th Annual Report of the Board of Commissioners of the Central Park for the Year Ending December 31, 1868
JOURNAL
Proceedings of the Geologists Association
METHOD OF RESEARCH
Commentary/editorial
SUBJECT OF RESEARCH
People
ARTICLE TITLE
The curious case of Central Park's dinosaurs: The destruction of Benjamin Waterhouse Hawkins' Paleozoic Museum revisited’
ARTICLE PUBLICATION DATE
10-May-2023
Scientists discover fire records embedded within sand dunes
The discovery could expand scientific understanding of fire histories to arid regions around the world
IMAGE: THE COOROIBAH WILDFIRE SWEEPS DOWN THE COOLOOLA SAND DUNES IN AUSTRALIA.view more
CREDIT: PHOTO BY MICHAEL FORD
Knowing how the frequency and intensity of wildfires has changed over time offers scientists a glimpse into Earth’s past landscapes, as well as an understanding of future climate change impacts. To reconstruct fire records, researchers rely heavily on sediment records from lake beds, but this means that fire histories from arid regions are often overlooked. Now, a new study shows that sand dunes can serve as repositories of fire history and aid in expanding scientific understanding of fire regimes around the world.
Published May 11 in Quaternary Research, the study is the first to examine sedimentary records preserved in foot-slope deposits of sand dunes. The research team, led by Nicholas Patton, Ph.D., a postdoctoral researcher now at DRI, studied four sand dunes at the Cooloola Sand Mass in Australia. Australia is one of the world’s most fire-prone landscapes, with a long history of both natural and cultural burning, and vast expanses without lakes or ponds to gather sedimentary records from. The researchers aimed to prove that these sand dune deposits could be used to reconstruct reliable, multi-millennial fire histories. These previously unrecognized archives could potentially be used in arid regions around the world to fill knowledge gaps in places where fire shapes the landscape.
“Many fire and paleoclimate records are located where there's a lot of water bodies such as lakes, peats, and bogs,” Patton says. “And because of this, most global models really have a bias towards temperate regions.”
The Cooloola Sand Mass consists of enormous – up to 240-meter-tall – sand dunes that build up at the coast and gradually shift inland from the power of the wind. By identifying the age of the dunes using a technique called optically stimulated luminescence dating, or OSL, Patton’s team found that the four dunes span the Holocene, representing the last approximately 12,000 years.
Once a dune is stable, meaning it is no longer growing but slowly degrading, the force of gravity acts on the dune slopes to collect falling sand at the base, along with the remnants of charcoal from local fires that deposited on the dune’s surface. This sediment builds up over time, layering charcoal from fire events that can be reliably identified using radiocarbon dating.
“We were digging soil pits at the base of the dunes and were seeing a lot of charcoal – more charcoal than we expected,” says Patton. “And we thought maybe we could utilize these deposits to reconstruct local fires within the area.”
Patton found that on the younger dunes (at 500 years old and 2,000 years old), charcoal layers represented individual fires, because the steep slope of the dunes quickly buried each layer. However, the older dunes (at 5,000 years old and 10,000 years old) had more gradual slopes that blended charcoal from different fires over time, providing a better understanding of periods of increased or decreased fire frequency.
The dunes offered localized fire histories from within an approximate 100-meter radius, so fire records vary somewhat amongst the four dunes, which spanned approximately 2 kilometers. However, Patton’s team compared their results to other fire records from the region found in lake and swamp deposits. Similar to the regional records, their findings showed three major periods of fire activity over the past 7,000 years.
The researchers write that similar records are likely held in sand dunes around the world, and that regions like California and the Southwest U.S. could benefit from a better understanding of regional fire history. Embedded within the fire records is not only information about natural wildfires, but also the way that humans influenced fire regimes.
“Fire histories are important for understanding how fire was used in the past for cultural purposes, whether that was to clear fields for agriculture or for hunting,” Patton says.
Patton hopes to continue this line of research at other dunes near the Cooloola Sand Mass that are nearly 1 million years old to obtain a long-term fire history for the region. Because Australia has had human communities for at least 60-70 thousand years, and quite possibly longer, these records could help understand the relationship between humans and historical fire regimes.
“These kinds of long-term records aren't always available within lake sediments, but they might be available within these dune deposits,” Patton says. “That's pretty exciting.”
###
More information: The full study, Reconstructing Holocene fire records using dune foot-slope deposits at the Cooloola Sand Mass, Australia, is available from Quaternary Research. DOI: https://doi.org/10.1017/qua.2023.14
Study authors include: Nicholas Patton (DRI/Univ. of Canterbury, NZ/Univ. of Queensland, AUS), James Shulmeister (Univ. of Canterbury, NZ/Univ. of Queensland, AUS), Quan Hua (Australian Nuclear Science and Technology Organization), Peter Almond (Lincoln University, NZ), Tammy Rittenour (Utah State Univ.), Johanna Hanson (Univ. of Canterbury, NZ), Aloysius Grealy (Univ. of Queensland, AUS), Jack Gilroy (Univ. of Queensland, AUS), Daniel Ellerton (Univ. of Queensland, AUS/Stockholm Univ.)
About DRI
The Desert Research Institute (DRI) is a recognized world leader in basic and applied environmental research. Committed to scientific excellence and integrity, DRI faculty, students who work alongside them, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge on topics ranging from humans’ impact on the environment to the environment’s impact on humans. DRI’s impactful science and inspiring solutions support Nevada’s diverse economy, provide science-based educational opportunities, and inform policymakers, business leaders, and community members. With campuses in Las Vegas and Reno, DRI serves as the non-profit research arm of the Nevada System of Higher Education. For more information, please visit www.dri.edu.
IMAGE: FRASER ISLAND FIRE ON K’GARI IN 2020 WHICH BURNED OVER 50% OF THE ISLAND.view more
CREDIT: QUEENSLAND FIRE AND EMERGENCY SERVICES
A previously unrecognised sedimentary archive in sand dunes could unlock a repository of fire records, a discovery that could expand fire histories across the globe.
The research, conducted by Dr Nicholas Patton during his PhD at The University of Queensland, has solved a persistent problem facing historians investigating changing fire patterns.
“Knowing how the frequency and intensity of wildfires has changed over time offers scientists a glimpse into Earth’s past landscapes, as well as an understanding of future climate change impacts,” Dr Patton said.
“To reconstruct fire records, researchers usually rely heavily on sediment records from lake beds, but this means that fire histories from dryland regions are often overlooked.”
“We’ve now shown that sand dunes can serve as repositories of fire history and aid in expanding scientific understanding of fire regimes around the world.”
The study is the first to systematically examine sedimentary records preserved in foot-slope deposits of sand dunes – specifically, four sand dunes at the Cooloola Sand Mass in Queensland, looking at approximately 12,000 years of history.
The researchers aimed to prove that these sand dune deposits could be used to reconstruct reliable, multi-millennial fire histories.
“The Cooloola Sand Mass consists of large sand dunes that were created off the coast and moved inland from the power of the wind,” Dr Patton said.
“We were digging soil pits at the base of the dunes and were seeing a lot of charcoal – more charcoal than we expected.
“And we thought maybe we could utilise these deposits to reconstruct local fires within the area.”
They were correct, and were delighted to see that their dune-based fire history findings successfully matched other fire records from the region found in lake and swamp deposits.
“We found that on the younger dunes – at 500 years old and 2,000 years old – charcoal layers represented individual fires, because the steep slope of the dunes quickly buried each layer,” Dr Patton said.
“However, the older dunes – at 5,000 years old and 10,000 years old – had more gradual slopes that blended charcoal from different fires over time, providing a better understanding of periods of increased or decreased fire frequency.”
The dunes offered localised fire histories from within an approximate 100-meter radius, so fire records varied somewhat amongst the four dunes, which spanned approximately two kilometres.
“Similar records are likely held in sand dunes around the world, and regions like California and the Southwest U.S. could benefit from a better understanding of regional fire history,” Dr Patton said.
“Embedded within the fire records is not only information about natural wildfires, but also the way that humans influenced fire regimes.
“Fire histories are important for understanding how fire was used in the past for cultural purposes, whether that was to clear fields for agriculture or for hunting.
“These records have the potential to unlock the role climate and/or Indigenous peoples had on the landscape from regions where they are rare or absent.
“It would be exciting to see this work extended into the Kimberley and the dune areas along the northern Australian coast where humans have lived for tens of thousands of years.”
The research was conducted between UQ, The University of Canterbury and the Desert Research Institute.
Reconstructing Holocene fire records using dune footslope deposits at the Cooloola Sand Mass, Australia
ARTICLE PUBLICATION DATE
11-May-2023
Global warming puts whales in the Southern Ocean on a diet
In the autumn, when right whales swim towards the coasts of South Africa, they ought to be fat and stuffed full. But in recent years, they have become thinner because their food is disappearing with the melting sea ice.
IMAGE: A SOUTHER RIGHT WHALE MOTHER WITH IT'S CALF SWIMMING IN THE WATERS NEAR THE COAST OF SOUTH AFRICA.view more
CREDIT: FREDRIK CHRISTIANSEN
In the month of June, when winter bites in the southern hemisphere and the sea around the Antarctic freezes over, right whales swim north. Many of them gather in the bay outside the town of Hermanus in South Africa.
Here, the warmer South African water is perfect for mating or raising newborn calves. However, there is no food for the whales, and all winter long the right whale mothers use up their fat reserves to produce milk for their calves.
It is therefore extremely important that the whales eat a lot and fatten up in the cold waters around the Antarctic throughout the summer. But it seems there is not enough food. The whales arriving at the coasts of South Africa are thinner than they used to be.
This is the result of new research from Aarhus University. Since the researchers started to measure right whales in the 1980s, the whales have become increasingly thinner. This is explained by Fredrik Christiansen, a senior researcher at the Department of Ecoscience at Aarhus University, who is behind the new results.
"Right whales are 25 per cent thinner than they were in the 1980s. This is bad for the whale population, because it means that the newborn whale calves have a higher risk of dying. Fortunately, the right whales in the Southern Ocean are not endangered, but if this continues, they could become so,” he says.
When the ice melts, food disappears When winter comes, and the cows leave the Antarctic and swim north, they have to cope for several months without food. Several months in which they eat into the fat reserves they have built up through the warm and light summer season.
Throughout the summer, right whales swim around beneath the sea ice, open their mouths to take in seawater, krill and water fleas. The baleen inside their mouth is a sort of a giant filter and it filters the small animals from the salt water. This allows the whales to eat huge amounts of food without using a lot of energy.
But the large shoals of krill are shrinking – and this means that the whales can’t fatten up before winter as they used to," explains Fredrik Christiansen.
“The shoals of krill live on phytoplankton, which thrive best in the cold waters around the Antarctic. Here – like plants on land – they transform sunlight into energy. Rising sea temperatures mean there is less phytoplankton, fewer krill and thus less food for the whales.
Instead, the whales forage for food further north, where there is another and less energy-rich form of krill.
“Further north, there’s less food for these small crustaceans. Therefore, they’re not as big and fat as the animals living beneath the Antarctic sea ice,” he says.
How to weigh a whale How exactly do scientists know that the whales have become thinner? Do Fredrik Christiansen and his colleagues lift the huge animals out of the water with oversized weighing scales? No, he explains. Instead, the researchers have invented a method to work out the weight of the whales based on photographs taken by drones.
“Right whales like to lie flat on the sea surface. This makes them easy to photograph from above. When the drone has taken some photographs – and we know the height of the drone – we can calculate the size of the animal," he explains.
However, in order to know the weight of the whale, it is necessary to know the volume of the whale – not just the length and width. But because scientists like Fredrik Christiansen have observed many right whales rolling around on the sea surface over the years – and thereby have been able to measure their size – the scientists now know the relationship between length, width and volume of the whales.
"We calculate the volume using the drone photographs – and when we know the volume, we more or less know the weight. In this way, we can see that the whales have become thinner over the past 30 years – and that’s serious. The weight of the mothers has a huge impact on their calves,” he says.
Small and weak whale calves Thirty to forty years ago, the southern right whale had calves every three years on average. But this is no longer true, explains Fredrik Oscar Christiansen.
“In the 1980s, researchers observed that the right whales off the coast of South Africa gave birth to a new calf every three years. But because it’s now difficult for them to fatten up during summer, this has fallen to every five years. This means that the population is growing significantly more slowly.
And not only do the whale calves come more rarely. The calves born today are smaller and grow more slowly.
“The amount of fat on the whale mother is directly linked to how much energy she can give to her calf through her milk. When the mother is thin, the calf gets less energy and grows more slowly,” he says.
The researchers have discovered that the northern right whales in the waters off Canada and the northern US are not growing quite as big as before. This is possibly because the calves are born smaller. According to the researchers' calculations, a whale born in 2019 will be one metre shorter on average when it is fully grown than a whale born in 1981.
"Small calves have a higher risk of dying. They’re more vulnerable if a killer whale attacks.”
Hunted close to extinction Right whales were given their name because they were considered the "right" whales to catch. People began hunting the large whales as early as in the 14th century, and for hundreds of years, they were hunted fiercely in both northern and southern parts of the Atlantic.
Oil from the whales' fat was one of the most important sources of energy. Train oil, which the oil used to be called, became a fuel in lamps – both for indoors and for street lights. The demand for train oil was also one of the most important reasons why Denmark colonised Greenland in the 18th century.
Around 1900, train oil was replaced by another more efficient energy source: crude oil. The black gold pumped up from the underground meant that whale hunting was no longer profitable.
The southern right whale is one of the species that benefitted from the end of whaling. For more than 100 years, the population has been allowed to grow large and healthy again. And this is not just good for the whales, but also for the entire Southern Ocean ecosystem.
Because the whales bring nourishment to areas of the sea with little food.
Extremely important for the marine ecosystem The sea around the Antarctic where the right whales come to eat has more life than any other sea on the planet. Despite the fact that the area only contains five per cent of the Earth's sea water, 20 per cent of all marine life lives in the area.
The many hours of sunshine in the summer, turbulent sea currents and the low temperature are perfect for teeming life.
The light makes marine algae grow explosively. The sea currents swirl the algae and nourishment around so that krill and plankton can gorge themselves. When full, the small crustaceans reproduce and form gigantic swarms. In some places, there may be as many as 35,000 krill in one cubic metre of water.
The right whales – and many other animals – stuff themselves with the abundance of krill, but unlike many other species, the whales migrate thousands of kilometres north to overwinter.
“The whales are extremely important for the parts of the sea where there is not much food. When the whales die, their huge bodies sink to the bottom. In the depths, they become food for a whole ecosystem of eel, sharks, crabs, lobsters, worms and microorganisms,” says Fredrik Christiansen.
So, if the whales disappear, it will have major consequences for many other animals.
“The whales are an apex predator. When an animal at the top of the food chain disappears, it has a cascade effect. Animals throughout the food chain will be affected if the whales are no longer there. From sharks to bacteria,” he concludes.
All photos used in this article have been taken by drones. It's the same photos that the researchers use to calculate the weight of the whales.
The southern right whales used to give birth every third year, but because of the lack of food five years passes between every birth.
INSTITUTE OF ATMOSPHERIC PHYSICS, CHINESE ACADEMY OF SCIENCES
IMAGE: OBSERVED DECADAL SHIFTS AND TRENDS IN GLOBAL TROPICAL CYCLONE ACTIVITIES FROM 1980-2021view more
CREDIT: WIDANA ARACHCHIGE ERANDANI LAKSHANI
Tropical cyclone (TCs) are one of the most destructive types of weather event on Earth, damaging people’s lives and their property, local infrastructure, and subsequently causing enormous economic losses. TCs are strong circular storms originating in the warm tropical oceans and are accompanied by heavy rainfall and strong winds. However, there has been no consensus amongst scientists regarding the global-scale trends of TC frequency and intensity due to climate change effects on ocean temperatures. Hence, to achieve this, and ultimately be better prepared for these extreme weather events in the future, a holistic evaluation of the different TC characteristics across ocean basins is vital.
In a recent study published in Atmospheric and Oceanic Science Letters, Professor Wen Zhou from Fudan University, China, and Erandani Lakshani, a post-graduate researcher at the City University of Hong Kong, have shed more light on the observed decadal-scale shifts and trends in global TC activities from 1980 to 2021.
The study reveals that there has been a significant increase in the number of TCs in the North Atlantic basin and North Indian Ocean over the past four decades, while there has been a decrease in the western North Pacific. It was also found that the genesis of TCs in the East Pacific, southern Indian Ocean, and South Pacific Ocean basins has declined since 1980, albeit this trend is not statistically significant.
Along with the frequency of TC genesis, the intensity of TCs has also varied significantly amongst the different ocean basins. “Notably, the average maximum TC intensity over the North Indian Ocean has increased recently, and this can be explained by an upward trend in mid-tropospheric relative humidity and decreasing vertical wind shear in the this basin”, outlines Professor Zhou and Lakshani. Their study also points out that the average TC intensity in the East Pacific has decreased dramatically, whereas over the South Pacific it has increased significantly.
Moreover, they observed an increasing TC intensity trend in the western North Pacific but a decreasing trend over the North Atlantic. The TC intensity in the North Atlantic may be linked to the decreasing trend in mid-tropospheric relative humidity, mainly south of the North Atlantic.
Another finding of this work is the indication of a significant association between the average large-scale characteristics of both vertical wind shear and relative humidity and the TC frequency in the different ocean basins. Moreover, the interdependence of TC frequency, vertical wind shear and relative humidity varies across the basins, indicating an inter-basin teleconnection (a term used in the atmospheric sciences to describe climate links between geographically separated regions).
In summary, this study provides valuable insights into global TC trends, which is critical towards improving our understanding of the evolution of TCs. Moreover, the study highlights the need for continued research into the underlying causes of these shifts in TC activity for future predictability and preparedness.
KAVLI INSTITUTE FOR THE PHYSICS AND MATHEMATICS OF THE UNIVERSE
IMAGE: SCHEMATIC OF THE INFLATON FIELD FRAGMENTED INTO OSCILLONS, WITH SUPERIMPOSED GRAVITATIONAL WAVES.view more
CREDIT: KAVLI IPMU, VOLODYMYR TAKHISTOV
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.
Details of their study were published in Physical Review Letters on May 2.
