Pythons are true choke artists

Size alone doesn't explain how invasive Burmese pythons eat such big prey

Peer-Reviewed Publication

UNIVERSITY OF CINCINNATI

 

IMAGE: ECOLOGISTS WITH THE CONSERVANCY OF SOUTHWEST FLORIDA CAPTURE A 215-POUND BURMESE PYTHON IN EVERGLADES NATIONAL PARK. view more 

CREDIT: IAN BARTOSZEK/CONSERVANCY OF SOUTHWEST FLORIDA

Burmese pythons are not just big snakes, growing to more than 18 feet and 200 pounds, but big eaters, taking on prey as large as a deer.

Biologists at the University of Cincinnati found that it’s not just the size of its head and body that puts almost everything on a python’s menu. They evolved super-stretchy skin between their lower jaws that allows them to consume prey up to six times larger than similar-sized snakes.

The study, funded in part by a grant from the National Science Foundation, was published in the journal Integrative Organismal Biology.

Since most snakes swallow prey whole, they must have wide mouths to accommodate a meal. Unlike our lower jawbone, the lower jawbones of snakes are not connected, allowing them to open wide.

“The stretchy skin between left and right lower jaws is radically different in pythons. Just over 40% of their total gape area on average is from stretchy skin,” lead author and UC biology professor Bruce Jayne said. “Even after you correct for their large heads, their gape is enormous.”

Pythons are constrictors. They bite their prey and wrap their powerful coils around it, fatally cutting off the animal’s vital blood flow, before consuming it whole at their leisure.

The bigger the prey, the more energy a snake derives from a meal. For pythons, that means not having to hunt as often, which can carry extensive risk in a world full of busy roads and dangerous predators.

Along with pythons, Jayne studied the gape size of brown tree snakes, a mildly venomous arboreal specialist that hunts birds and other animals in the forest canopy. Brown tree snakes were introduced in the 1950s to Guam, wiping out many bird species.

Besides measuring the snakes, Jayne also measured the dimensions and weight of potential prey animals. This allowed Jayne to use snake size to predict the maximal size of its prey and the relative benefits of consuming different types such as alligators, chickens, rats or deer.  

Small snakes derive greater benefits in relative prey mass from a modest increase in gape size, the study found. This gives python babies an early advantage in taking on a broader range of prey compared to other snakes their size, Jayne said.

Being big also helps snakes avoid becoming meals themselves. Snakes fall prey to everything from wading birds to minks and raccoons to alligators and other snakes.

“Once those pythons get to a reasonable size, it’s pretty much just alligators that can eat them,” Jayne said. “And pythons eat alligators.”

Like invasive brown tree snakes in Guam, Burmese pythons are wreaking havoc on the ecology of Everglades National Park where they were introduced due to the release of captive animals from the exotic pet trade in the 1980s.

Study co-author Ian Bartoszek works as an environmental science project manager for the Conservancy of Southwest Florida, where he has led a project to track pythons. They implant radio transmitters in male snakes during breeding season to find females before they can lay more clutches of eggs. A big female python can lay more than 100 eggs.

Researchers routinely find deer hooves and the remains of other big animals in their stomachs. Bartoszek photographed one python regurgitating a full-grown white-tailed deer.

“The Everglades ecosystem is changing in real time based on one species, the Burmese python,” Bartoszek said.

The good news is that pythons rarely attack people. Bartoszek said the only defensive encounters he’s had with wild pythons are with females guarding their nests.

“It’s way more dangerous to drive there than to work with the snakes,” he said.

CAPTION

University of Cincinnati professor Bruce Jayne demonstrates the gape of a euthanized Burmese python specimen in his lab.

CREDIT

Bruce Jayne

CAPTION

A Burmese python in Everglades National Park regurgitates a white-tailed deer.

CREDIT

Ian Bartoszek/Conservancy of Southwest Florida

CAPTION

University of Cincinnati professor Bruce Jayne works with a brown tree snake in his biology lab.

CREDIT

Joseph Fuqua II/UC

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JOURNAL

Integrative Organismal Biology

DOI

10.1093/iob/obac033 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Scaling Relationships of Maximal Gape in Two Species of Large Invasive Snakes, Brown Treesnakes and Burmese Pythons, and Implications for Maximal Prey Size

York University study: Even smartest AI models don’t match human visual processing

York University study highlights how deep-network models take potentially dangerous ‘shortcuts’ in solving complex recognition tasks

Peer-Reviewed Publication

YORK UNIVERSITY

TORONTO, Sept. 16, 2022 –  Deep convolutional neural networks (DCNNs) don’t see objects the way humans do – using configural shape perception – and that could be dangerous in real-world AI applications, says Professor James Elder, co-author of a York University study published today.

Published in the Cell Press journal iScience, Deep learning models fail to capture the configural nature of human shape perception is a collaborative study by Elder, who holds the York Research Chair in Human and Computer Vision and is Co-Director of York’s Centre for AI & Society, and Assistant Psychology Professor Nicholas Baker at Loyola College in Chicago, a former VISTA postdoctoral fellow at York.

The study employed novel visual stimuli called “Frankensteins” to explore how the human brain and DCNNs process holistic, configural object properties.

“Frankensteins are simply objects that have been taken apart and put back together the wrong way around,” says Elder.  “As a result, they have all the right local features, but in the wrong places.” 

The investigators found that while the human visual system is confused by Frankensteins, DCNNs are not – revealing an insensitivity to configural object properties.

“Our results explain why deep AI models fail under certain conditions and point to the need to consider tasks beyond object recognition in order to understand visual processing in the brain,” Elder says. “These deep models tend to take ‘shortcuts’ when solving complex recognition tasks. While these shortcuts may work in many cases, they can be dangerous in some of the real-world AI applications we are currently working on with our industry and government partners,” Elder points out.

One such application is traffic video safety systems: “The objects in a busy traffic scene – the vehicles, bicycles and pedestrians – obstruct each other and arrive at the eye of a driver as a jumble of disconnected fragments,” explains Elder. “The brain needs to correctly group those fragments to identify the correct categories and locations of the objects. An AI system for traffic safety monitoring that is only able to perceive the fragments individually will fail at this task, potentially misunderstanding risks to vulnerable road users.”

According to the researchers, modifications to training and architecture aimed at making networks more brain-like did not lead to configural processing, and none of the networks were able to accurately predict trial-by-trial human object judgements. "We speculate that to match human configural sensitivity, networks must be trained to solve broader range of object tasks beyond category recognition," notes Elder.  

York University is a modern, multi-campus, urban university located in Toronto, Ontario. Backed by a diverse group of students, faculty, staff, alumni and partners, we bring a uniquely global perspective to help solve societal challenges, drive positive change and prepare our students for success. York's fully bilingual Glendon Campus is home to Southern Ontario's Centre of Excellence for French Language and Bilingual Postsecondary Education. York’s campuses in Costa Rica and India offer students exceptional transnational learning opportunities and innovative programs. Together, we can make things right for our communities, our planet, and our future. 

Media Contact:

Gloria Suhasini, York University Media Relations, 647.463.4354, suhasini@yorku.ca

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JOURNAL

iScience

DOI

10.1016/j.isci.2022.104913 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Deep learning models fail to capture the configural nature of human shape perception

ARTICLE PUBLICATION DATE

16-Sep-2022

PRISON KILLS

Incarceration associated with higher cancer mortality, Yale study shows

Peer-Reviewed Publication

YALE UNIVERSITY

New Haven, Conn. — New research from Yale Cancer Center reveals a higher risk of cancer mortality in incarcerated adults, as well as among those diagnosed with cancer in the first year after release from prison.

The findings are published in the journal PLOS ONE.

“Cancer is the leading cause of death among people in prison, accounting for about 30% of all deaths, and yet the complex relationship between incarceration and cancer survival had not been thoroughly evaluated,” said Dr. Emily Wang, professor of medicine (General Medicine) and of public health (Social and Behavioral Sciences) and senior author of the study. She is also director of the SEICHE Center for Health and Justice at Yale.

The study compared data using a statewide link between tumor registry and correctional system data for adults in Connecticut diagnosed with invasive cancer from 2005 through 2016.

After accounting for demographics and cancer characteristics, including stage of diagnosis, the risk for cancer-related death at five years was significantly higher among those diagnosed while incarcerated and those recently released compared to the remainder of the population.

“This is a call to action,” said co-author Dr. Cary Gross, professor of medicine (General Medicine) and of epidemiology (Chronic Diseases), and founding director of the Cancer Outcomes, Public Policy and Effectiveness Research (COPPER) Center at Yale School of Medicine. “Cancer prevention and treatment efforts should target people while in prison and identify why incarceration is associated with worse outcomes.” 

Those diagnosed with invasive cancer while incarcerated and within one year after release were also more likely to be younger, male, and non-Hispanic Black or Hispanic. Cancers originating from the gastrointestinal system were the most common cancers in this population, followed by lung and prostate cancer, and leukemia and lymphoma.

“Possible reasons for the high risk of death include having limited access to high quality cancer care, access to palliative care, and attention to patients’ social determinants of health, including social support and food,” said Wang.

While prior studies have identified the association between incarceration and cancer survival time, this study illuminates the immediate post-release period as a particularly high-risk period.

“Our findings highlight the value and importance of transition centers for individuals released from carceral settings, the significant barriers associated with cancer care include screening, timely primary care, housing and food security, employment and other structural barriers faced by those re-integrating into society,” said lead author Dr. Oluwadamilola Oladeru, an assistant professor of radiation oncology at the University of Florida. Oladeru is also the co-clinical leader of the University of Florida Breast Center.

“Primary care for people recently released from correctional systems should include screening for treatable cancers, evaluation of symptoms, and addressing social determinants to mitigate these disparities in cancer related deaths,” said Gross. “Our findings may also be pertinent to other state prison systems as the national data reveal that cancer is now the leading cause of death among incarcerated individuals.” 

This research was supported by a National Institutes of Health grant.

Additional Yale authors include Pamela Soulos and Jenerius A. Aminawung.

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JOURNAL

PLoS ONE

Climate change from the ground up: Researchers explore sea level rise impact on building foundations

Study examines hidden costs to building foundations due to sea level rise

Peer-Reviewed Publication

COLORADO STATE UNIVERSITY

Researchers have considered how flooding from rising sea levels and storm surges will damage the built environment along the coast, but what about climate change’s less noticeable impacts below the surface?

A new study by Colorado State University civil engineers examines the hidden costs to building foundations due to sea level rise. They propose a method for inspection and repair to lower the cost associated with deterioration from saltwater corrosion.

The researchers, who are part of the NIST Center for Risk-Based Community Resilience Planning at CSU, say it is important to plan ahead – especially considering there are more than 16 million buildings along the U.S. Atlantic and Gulf coasts.

“This is a problem, and it’s going to cost a lot of money,” said Hussam Mahmoud, a professor in the Department of Civil and Environmental Engineering and co-author on the study.

One at-risk location

Engineers looked at nearly 137,000 residential buildings in low-lying regions in Mobile County, Alabama, and estimated probable foundation damage from saltwater corrosion.

As sea level rises, so does the groundwater table, and saltwater is more corrosive than freshwater. Using existing predictions for sea level rise and water table levels based on wells in Mobile, they predicted how long it would take for saltwater to reach the buildings’ foundations.

Under the most extreme sea level rise projections, they estimated the annual repair cost for foundations in Mobile could total $90 million by 2100.

“The significance here is that this value that we found for one of the saltwater intrusion scenarios is just for 137,000 buildings in Mobile,” Mahmoud said. “If you calculated the cost for the entire East Coast – or from the East to the West Coast – it would be staggering.”

Providing a solution

The engineers developed a formula to help building owners determine when to inspect and repair their buildings based on building location and the probability of saltwater corrosion. They say waiting for the right time to repair the foundation – but not so long that damage has been done – will save building owners money.

They also proposed the use of low-cost sensors to monitor the water table level near a building’s foundation and protect against uncertainties.

The researchers chose to study Mobile because it is an industrial port city with a large economically disadvantaged population. They have started investigating the impact of natural disasters on Mobile’s vulnerable communities to figure out the best way to allocate resources to help them recover in an emergency.

“In order for us to assess social and economic impact, we have to have a good understanding of the impact of the hazard on the built environment,” Mahmoud said.

Next, the team plans to examine structural performance beyond the foundation and how that affects people in the area. For example, how much wind and water surge during a hurricane can a structure withstand before alternative housing or shelters are needed?

“This work will allow us to be proactive about finding solutions quickly to help those in need, instead of waiting until it’s bad,” Mahmoud said.

Helping communities recover from natural disasters is the focus of the CSU-led Center for Risk-Based Community Resilience Planning, a $20 million partnership with the National Institute of Standards and Technology that involves collaborators from more than a dozen other universities.

The study, “Hidden costs to building foundations due to sea level rise in a changing climate,” is published in Scientific Reports. In addition to Mahmoud, authors are Mohamed A. Abdelhafez, a Civil and Environmental Engineering Ph.D. student, and Bruce Ellingwood, a recently retired professor of Civil and Environmental Engineering.

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JOURNAL

Scientific Reports

METHOD OF RESEARCH

Meta-analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Hidden costs to building foundations due to sea level rise in a changing climate

New Curtin-led research discovers the heart of our evolution

Peer-Reviewed Publication

CURTIN UNIVERSITY

 

IMAGE: THE GOGO FISH FOSSIL WHERE THE 380-MILLION-YEAR-OLD, 3D PRESERVED HEART WAS DISCOVERED BY RESEARCHERS. PICTURED AT THE WA MUSEUM. view more 

CREDIT: YASMINE PHILLIPS, CURTIN UNIVERSITY

Researchers have discovered a 380-million-year-old heart – the oldest ever found – alongside a separate fossilised stomach, intestine and liver in an ancient jawed fish, shedding new light on the evolution of our own bodies.

The new research, published today in Science, found that the position of the organs in the body of arthrodires - an extinct class of armoured fishes that flourished through the Devonian period from 419.2 million years ago to 358.9 million years ago - is similar to modern shark anatomy, offering vital new evolutionary clues.

Lead researcher John Curtin Distinguished Professor Kate Trinajstic, from Curtin’s School of Molecular and Life Sciences and the Western Australian Museum, said the discovery was remarkable given that soft tissues of ancient species were rarely preserved and it was even rarer to find 3D preservation.

“As a palaeontologist who has studied fossils for more than 20 years, I was truly amazed to find a 3D and beautifully preserved heart in a 380-million-year-old ancestor,” Professor Trinajstic said.

“Evolution is often thought of as a series of small steps, but these ancient fossils suggest there was a larger leap between jawless and jawed vertebrates. These fish literally have their hearts in their mouths and under their gills - just like sharks today.”

This research presents – for the first time – the 3D model of a complex s-shaped heart in an arthrodire that is made up of two chambers with the smaller chamber sitting on top.

Professor Trinajstic said these features were advanced in such early vertebrates, offering a unique window into how the head and neck region began to change to accommodate jaws, a critical stage in the evolution of our own bodies.

“For the first time, we can see all the organs together in a primitive jawed fish, and we were especially surprised to learn that they were not so different from us,” Professor Trinajstic said.

“However, there was one critical difference – the liver was large and enabled the fish to remain buoyant, just like sharks today. Some of today’s bony fish such as lungfish and birchers have lungs that evolved from swim bladders but it was significant that we found no evidence of lungs in any of the extinct armoured fishes we examined, which suggests that they evolved independently in the bony fishes at a later date.”  

The Gogo Formation, in the Kimberley region of Western Australia where the fossils were collected, was originally a large reef.

Enlisting the help of scientists at the Australian Nuclear Science and Technology Organisation in Sydney and the European Synchrotron Radiation Facility in France, researchers used neutron beams and synchrotron x-rays to scan the specimens, still embedded in the limestone concretions, and constructed three-dimensional images of the soft tissues inside them based on the different densities of minerals deposited by the bacteria and the surrounding rock matrix.

This new discovery of mineralised organs, in addition to previous finds of muscles and embryos, makes the Gogo arthrodires the most fully understood of all jawed stem vertebrates and clarifies an evolutionary transition on the line to living jawed vertebrates, which includes the mammals and humans.

Co-author Professor John Long, from Flinders University, said: “These new discoveries of soft organs in these ancient fishes are truly the stuff of palaeontologists’ dreams, for without doubt these fossils are the best preserved in the world for this age. They show the value of the Gogo fossils for understanding the big steps in our distant evolution. Gogo has given us world firsts, from the origins of sex to the oldest vertebrate heart, and is now one of the most significant fossil sites in the world. It’s time the site was seriously considered for world heritage status.”

Co-author Professor Per Ahlberg, from Uppsala University, said: “What's really exceptional about the Gogo fishes is that their soft tissues are preserved in three dimensions. Most cases of soft-tissue preservation are found in flattened fossils, where the soft anatomy is little more than a stain on the rock. We are also very fortunate in that modern scanning techniques allow us to study these fragile soft tissues without destroying them. A couple of decades ago, the project would have been impossible.”

The Curtin-led research was a collaboration with Flinders University, the Western Australian Museum, the European Synchrotron Radiation Facility in France, the Australian Nuclear Science and Technology Organisation’s nuclear reactor, Uppsala University, Monash University’s Australian Regenerative Medicine Institute and the South Australian Museum.

The full paper, titled ‘Exceptional preservation of organs in Devonian placoderms from the Gogo lagerstätte’, can be found online here.

The preserved stomach of a Gogo fish fossil under the microscope. Pictured at the WA Museum.

CREDIT

Yasmine Phillips, Curtin University

Gogo fish diorama at WA Museum Boola Bardip

CREDIT

Professor Kate Trinajstic, Curtin University

JOURNAL

Science

DOI

10.1126/science.abf3289 

SUBJECT OF RESEARCH

Animal tissue samples

ARTICLE TITLE

Exceptional preservation of organs in Devonian placoderms from the Gogo lagerstätte’

ARTICLE PUBLICATION DATE

16-Sep-2022

Marching with a message: Lethbridge event highlights challenges for those with disabilities

Eloise Therien - Yesterday 

Dozens of southern Albertans converged on Lethbridge city hall Friday morning, equipped with hand-written posters and a desire to spread a message.


Participants of the 2022 Citizen Walk About walking along 3rd Ave. S, 

Lethbridge on their way to Galt Gardens.© Eloise Therien / Global News

The annual Citizen Walk About looks to showcase the success of people with different abilities, with the theme, "How We Got Here."

The South Region Self-Advocacy Network (SRSAN) hosted the walk in partnership with Southern Alberta Individualized Planning Association (SAIPA).

"It is an awareness event meant to highlight issues in the disability sector," said SAIPA executive director Mark Davids.

"Both the accomplishments--where we are today, the great strides the people have managed to complete--as well as the work that still needs to be done."

Video: Osoyoos family fundraising to outfit their home for disabled son

The event saw participants move from city hall to Galt Gardens for entertainment, speakers and a barbecue lunch.

Organizers hoped along with spreading awareness, it would be a chance to build connections.

"It's showing that we are here too, so just showing our ability and what we can do," said Melodie Scout, who has been taking part for several years.

She said despite hardships and discrimination she has faced, she keeps a positive attitude.

"We're part of this community as well."

When asked what challenges are currently facing people living with disabilities, Davids said there are three main concerns.

"The effect of transportation, communication, as well as finances," he explained. "AISH (Assured Income for the Severely Handicapped) is not indexed at the moment, so as inflation continues to rise, it pushes people closer to poverty."

Ben Rowley, self-advocate and one of the organizers, said more can also be done to assist those with different mobility needs.

"There's a lot of issues for people with disabilities that you might not understand," Rowley said. "Like getting into older buildings and not having that accessibility."

According to it's website, SAIPA was formed in 1986 as a charitable non-profit "which supports people with disabilities to drive change in their communities as engaged and empowered citizens."

Davids said many of its services are free and encourages community members to reach out for more information.

AISH IS JOINTLY FUNDED BY FEDERAL TRANSFER PAYMENTS AS WELL SUPPOSEDLY BY ALBERTA MATCHING IT.

IN FACT THE AB GOV ONLY ISSUES THE FEDERAL PORTION TO AISH RECIPIENTS, NOT ADDING ADDITIONAL AB FUNDING. 

JUST AS IT CHEATS PARENTS OUT OF PROVINCIAL FUNDING FOR DAYCARE RELYING ON GIVING THEM ONLY THE FEDERAL PAYMENT.

How songbirds’ striking colors put them at risk

Peer-Reviewed Publication

CELL PRESS

 

IMAGE: COMMON HILL MYNA (GRACULA-RELIGIOSA); LEAST CONCERN; COLOR UNIQUENESS SCORE OF 66.9 view more 

CREDIT: RICK STANLEY AND GABBY SALAZAR

Bright, uniquely colored songbirds are at higher risk of extinction and more likely to be traded as pets, according to researchers reporting in Current Biology on September 15. The researchers also predict that almost 500 additional bird species, most of them living in the tropics, are at risk of future trade based on their unique and desirable coloration.

“Aesthetic value is an important part of how people value nature,” said Rebecca Senior (@RebeccaASenior) of Durham University, U.K. “However, there is potential for conflict when what motivates some people to protect certain species is the same thing that makes other people want to own them. Songbirds are highly sought after in the pet trade, particularly for their beautiful songs. However, songbirds can also be remarkably colorful—a highly desirable trait in other commonly traded species, such as parrots.”

In their new study, Senior and colleagues including Brett Scheffers (@BrettScheffers) of University of Florida, Gainesville explored the antagonistic roles of aesthetic value in biodiversity conservation. They used novel metrics of color to evaluate the aesthetics of groups of birds, across the world and the avian tree of life.

Their analysis shows that the tropics are the epicenter of bird color, with 91% and 65% of the world’s most diverse and uniquely colored assemblages of songbirds, respectively. They report that the pet trade, which affects 30% of all bird species, targets clusters of related and uniquely colored birds. They went on to identify 478 species of birds that may be at risk of future trade based on their appealing colors.

“We were surprised to see the strength of the latitudinal gradient in color; even when you account for the greater number of species in the tropics, the diversity of color in the tropics dwarfs all other regions,” Senior said.

While one might expect brilliant blues, oranges, and yellows to put species at risk, the researchers were also surprised to discover that pure white is a unique color found in many sought-after species, such as the endangered Bali myna. The findings overall highlight that the same color features that make some people willing to travel around the world for a mere glimpse of a bird through binoculars also potentially puts them at risk for pet trading. The findings have important implications for conservation.

“Understanding what motivates trade is essential to identify at-risk species potentially requiring more proactive protection from trapping,” Senior said. “Trade has the capacity to be regulated and managed sustainably with a better understanding of what is traded as well as where and why trade occurs. Loss of colorful species also directly erodes aesthetic value, which is problematic because, for better or worse, it is this value that often fundamentally motivates and funds conservation efforts.”

In future studies, they hope to disentangle even more factors that play into regional variation in patterns of trade among birds. They’d also like to explore the role of color in the trade of other groups of animals and plants.

###

This work was supported by a Royal Society of New Zealand Marsden grant and the Alfred P. Sloan Research Fellowship.

Current Biology, Senior et al. “Wildlife trade targets colorful birds and threatens the aesthetic value of nature” https://www.cell.com/current-biology/fulltext/S0960-9822(22)01215-5

Current Biology (@CurrentBiology), published by Cell Press, is a bimonthly journal that features papers across all areas of biology. Current Biology strives to foster communication across fields of biology, both by publishing important findings of general interest and through highly accessible front matter for non-specialists. Visit http://www.cell.com/current-biology. To receive Cell Press media alerts, contact press@cell.com.

Bornean green magpie (Cissa thalassina); Critically Endangered; color uniqueness score of 42.5

CREDIT

Zhikai Liao

Black-winged myna (Acridotheres-melanopterus); Endangered

CREDIT

Rick Stanley and Gabby Salazar

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JOURNAL

Current Biology

DOI

10.1016/j.cub.2022.07.066 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Wildlife trade targets colourful birds and threatens the aesthetic value of nature

ARTICLE PUBLICATION DATE

15-Sep-2022

Byzantine solar eclipse records illuminate obscure history of Earth's rotation

Japanese researchers investigated ancient texts from the 4th to 7th centuries CE to identify five total solar eclipses near the Eastern Mediterranean and improve the model of the Earth's rotation over time

Peer-Reviewed Publication

UNIVERSITY OF TSUKUBA

Tsukuba, Japan—Witnessing a total solar eclipse is an unforgettable experience and may have been even more impressive throughout history before we were able to understand and accurately predict their occurrence. But the historical records of these remarkable astronomical spectacles are more than mere curiosities—they provide invaluable information on changes in the Earth's movement.

In a new study in Publications of the Astronomical Society of the Pacific, Japanese researchers combed through records from the Byzantine Empire to identify and locate total solar eclipses observed around the Eastern Mediterranean in the 4th-7th centuries CE, a period for which previously identified solar eclipse records are particularly scarce.

These records are crucial for understanding the variability of the Earth's rotation throughout history. However, because the people who recorded these events in antiquity often left out key information of interest to modern astronomers, identifying the correct times, locations, and extents of historical eclipses is painstaking work.

"Although original eyewitness accounts from this period have mostly been lost, quotations, translations, etc., recorded by later generations provide valuable information," co-author Assistant Professor Koji Murata of the University of Tsukuba explains. "In addition to reliable location and timing information, we needed confirmation of eclipse totality: daytime darkness to the extent that stars appeared in the sky. We were able to identify the probable times and locations of five total solar eclipses from the 4th to 7th centuries in the Eastern Mediterranean region, in 346, 418, 484, 601, and 693 CE."

The key variable that this new information sheds light on is ΔT, the difference between time measured according to the Earth's rotation and time independent of the Earth's rotation. Thus, variations in ΔT represent variations in the actual length of a day on Earth.

Taking the eclipse of July 19, 418 CE as an example, an ancient text reported a solar eclipse so complete that stars appeared in the sky, and the site of observation was identified as Constantinople. The previous ΔT model for this time would have placed Constantinople outside the path of totality for this eclipse. Therefore, ΔT for the 5th century CE can be adjusted based on this new information.

"Our new ΔT data fill a considerable gap and indicate that the ΔT margin for the 5th century should be revised upward, whereas those for the 6th and 7th centuries should be revised downward" says Dr. Murata.

These new data shed light on variation of the Earth's rotation on a centennial timescale, and thus help refine the study of other global phenomena throughout history, such as sea-level and ice-volume variability.

###
This work was financially supported in part by JSPS Grant-inAids JP15K05038, JP19K13389, JP20K22367, JP20K20918, JP20H05643, and JP21K13957, JSPS Overseas Challenge Program for Young Researchers, the ISEE director's leadership fund for FY2021, Young Leader Cultivation (YLC) program, and YLC collaboration project of Nagoya University, and Tokai Pathways to Global Excellence (Nagoya University) of the Strategic Professional Development Program for Young Researchers (MEXT). We thank the Bibliothèque Nationale de France and the British Library for letting us access and reproduce MS Coislin 249 and MS Or 818.

Original Paper

The article, "The Variable Earth's Rotation in the 4th-7th Centuries: New ΔT Constraints from Byzantine Eclipse Records," was published in Publications of the Astronomical Society of the Pacific at DOI: 10.1088/1538-3873/ac6b56

Correspondence

Assistant Professor MURATA Koji
Faculty of Library, Information and Media Science, University of Tsukuba

Related Link

Faculty of Library, Information and Media Science

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JOURNAL

Publications of the Astronomical Society of the Pacific

DOI

10.1088/1538-3873/ac6b56 

ARTICLE TITLE

The Variable Earth's Rotation in the 4th-7th Centuries: New ΔT Constraints from Byzantine Eclipse Records

ARTICLE PUBLICATION DATE

13-Sep-2022