Margaret Allen

Research: SMU-led fossil study finds carbon dioxide link to global warming 22 million years ago

Fossil leaves from Ethiopia

Variations in the concentration of atmospheric carbon dioxide affect carbon fixation during photosynthesis and can be measured on a preserved fossil leaf like this one from Ethiopia.

Fossil leaves from Africa have resolved a prehistoric climate puzzle — and also confirm the link between carbon dioxide in the atmosphere and global warming.

Research until now has produced a variety of results and conflicting data that have cast doubt on the link between high carbon dioxide levels and climate change for a time interval about 22 million years ago.

But a new study has found the link does indeed exist for that prehistoric time period, say SMU researchers. The finding will help scientists understand how recent and future increases in the concentration of atmospheric carbon dioxide may impact the future of our planet, they add.

The discovery comes from new biochemical analyses of fossil leaves from plants that grew on Earth 27 million years ago and 22 million years ago, said geologist Tekie Tesfamichael, an SMU postdoctoral fellow in Earth Sciences and a lead scientist on the research.

The new analyses confirm research about modern climate — that global temperatures rise and fall with increases and decreases in carbon dioxide in our atmosphere — but in this case even in prehistoric times, according to the SMU-led international research team.

Carbon dioxide is a gas that is normally present in the Earth’s atmosphere, even millions of years ago. It’s dubbed a greenhouse gas because greater concentrations cause the overall temperature of Earth’s atmosphere to rise, as happens in a greenhouse with lots of sunlight.

Recently greenhouse gas increases have caused global warming, which is melting glaciers, sparking extreme weather variability and causing sea levels to rise.

The new SMU discovery that carbon dioxide behaved in the same manner millions of years ago that it does today has significant implications for the future. The finding suggests the pairing of carbon dioxide and global warming that is seen today also holds true for the future if carbon dioxide levels continue to rise as they have been, said Tesfamichael.

“The more we understand about the relationship between atmospheric carbon dioxide concentrations and global temperature in the past, the more we can plan for changes ahead,” said Tesfamichael.

“Previous work reported a variety of results and conflicting data about carbon dioxide concentrations at the two intervals of time that we studied,” he said. “But tighter control on the age of our fossils helped us to address whether or not atmospheric carbon dioxide concentration corresponded to warming — which itself is independently well-documented in geochemical studies of marine fossils in ocean sediments.”

The researchers reported their findings in Geology, the scientific journal of the Geological Society of America. The article is “Settling the issue of ‘decoupling’ between atmospheric carbon dioxide and global temperature: [CO2]atm reconstructions across the warming Paleogene-Neogene divide.”

Co-authors from the Roy M. Huffington Department of Earth Sciences in Dedman College are professors Bonnie Jacobs, an expert in paleobotany and paleoclimate, and Neil J. Tabor, an expert in sedimentology and sedimentary geochemistry. Other co-authors are Lauren Michel, Tennessee Technological University; Ellen Currano, University of Wyoming; Mulugeta Feseha, Addis Ababa University; Richard Barclay, Smithsonian Institution; John Kappelman, University of Texas; and Mark Schmitz, Boise State University.

— Written by Margaret Allen

> Read the full story at the SMU Research blog: smuresearch.com

Research: SMU scientists help solve the mystery of climate and leaf size

Conifer needlesWhy is a banana leaf a million times bigger than a common heather leaf? Why are leaves generally much larger in tropical jungles than in temperate forests and deserts? The textbooks say it’s a balance between water availability and overheating – but researchers have found that it’s not that simple.

SMU paleobotanist Bonnie F. Jacobs has contributed work to a major new study that provides scientists with a new tool for understanding both ancient and future climate by looking at the size of plant leaves.

The study, published in the Sept. 1, 2017 issue of Science, was led by Associate Professor Ian Wright from Macquarie University, Australia. The study’s findings reveal that in much of the world the key factor limiting the size of a plant’s leaves is the temperature at night and the risk of frost damage to leaves.

Jacobs said the implications of the study are significant for enabling scientists to either predict modern leaf size in the distant future, or to understand the climate for a locality as it may have been in the past.

“This research provides scientists with another tool for predicting future changes in vegetation, given climate change, and for describing ancient climate given fossil leaves,” said Jacobs, a professor in SMU’s Roy M. Huffington Department of Earth Sciences in the Dedman College of Humanities and Sciences.

“Now we can reliably use this as another way to look at future climate models for a specific location and predict the size of plant leaves,” she said. “Or, if we’re trying to understand what the climate was for a prehistoric site tens of millions of years ago, we can look at the plant fossils discovered in that location and describe what the climate most likely was at that time.”

Wright, Jacobs and 15 colleagues from Australia, the U.K., Canada, Argentina, the United States, Estonia, Spain and China analyzed leaves from more than 7,600 species, then pooled and analyzed the data with new theory to create a series of equations that can predict the maximum viable leaf size anywhere in the world based on the risk of daytime overheating and night-time freezing.

The researchers will use these findings to create more accurate vegetation models. This will be used by governments to predict how vegetation will change locally and globally under climate change, and to plan for adaptation.

“The conventional explanation was that water availability and overheating were the two major limits to leaf size. But the data didn’t fit,” says Wright. “For example the tropics are both wet and hot, and leaves in cooler parts of the world are unlikely to overheat.”

“Our team worked both ends of the problem – observation and theory,” he says. “We used big data – measurements made on tens of thousands of leaves. By sampling across all continents, climate zones and plant types we were able to show that simple ‘rules’ seemingly operate across the world’s plant species, rules that were not apparent from previous, more limited analyses.”

Jacobs contributed an extensive leaf database she compiled about 20 years ago, funded by a National Science Foundation grant. She analyzed the leaf characteristics of 880 species of modern tropical African plants, which occurred in various combinations among 30 plant communities. Jacobs measured leaves of the plant specimens at the Missouri Botanical Garden Herbarium, one of the largest archives of pressed dried plant specimens from around the world.

She looked at all aspects of leaf shape and climate, ranging from seasonal and annual rainfall and temperature for each locale, as well as leaf shape, size, tip, base, among others. Using statistical analyses to plot the variables, she found the most prominent relationship between leaf shape and climate was that size increases with rainfall amount. Wet sites had species with larger leaves than dry sites.

Her Africa database was added to those of many other scientists who have compiled similar data for other localities around the world.

— Written by Margaret Allen

> Read the full story from the SMU Research blog

Research: Gamers join researchers in the fight against cancer

John Wise, Pia Vogel and Corey Clark

SMU researchers (l-r) John Wise, Pia Vogel and Corey Clark are tapping the power of an online gaming community to fight cancer. Photo: Hillsman S. Jackson

The massive computational power of an online gaming community has even more clout than supercomputers in the fight against cancer, according to SMU biochemical researchers and video game developers. The two groups are partnering with the world’s vast network of gamers in hopes of discovering a new cancer-fighting drug.

Biochemistry professors Pia Vogel and John Wise in the Department of Biological Sciences and Corey Clark, deputy director of research at SMU Guildhall, are leading the University’s assault on cancer in partnership with fans of the best-selling video game Minecraft.

With 122 million copies of the game sold worldwide and more than 55 million active players each month as of February 2017, Vogel and Wise expect deep inroads in their quest to narrow the search for chemical compounds that improve the effectiveness of chemotherapy drugs.

“Crowdsourcing as well as computational power may help us narrow down our search and give us better chances at selecting a drug that will be successful,” said Vogel. “And gamers can take pride in knowing they’ve helped find answers to an important medical problem.”

Up to now, Wise and Vogel have tapped the high-performance computing power of SMU’s Maneframe, one of the most powerful academic supercomputers in the nation. With ManeFrame, Wise and Vogel have sorted through millions of compounds that have the potential to work. Now, the biochemists say, it’s time to take that research to the next level — crowdsourced computing.

A network of gamers can crunch massive amounts of data during routine gameplay by pairing two powerful weapons: the best of human intuition combined with the massive computing power of networked gaming machine processors.

Taking their research to the gaming community will more than double the amount of machine processing power attacking their research problem.

“With the distributed computing of the actual game clients, we can theoretically have much more computing power than even the supercomputer here at SMU,” said Clark, who is also an adjunct research associate professor in the Department of Biological Sciences. In March, SMU Guildhall was named No. 1 among the world’s Top 25 Graduate Schools for Video Game Design by The Princeton Review.

“If we take a small percentage of the computing power from 25,000 gamers playing our mod we can match ManeFrame’s 120 teraflops of processing power,” Clark said. “Integrating with the Minecraft community should allow us to double the computing power of that supercomputer.”

Even more importantly, the gaming community adds another important component — human intuition.

Wise believes there’s a lot of brainpower eager to be tapped in the gaming community. And human brains, when tackling a problem or faced with a challenge, can make creative and intuitive leaps that machines can’t.

“What if we learn things that we never would have learned any other way? And even if it doesn’t work it’s still a good idea and the kids will still get their endorphin kicks playing the game,” Wise said. “It also raises awareness of the research. Gamers will be saying ‘Mom, don’t tell me to go to bed, I’m doing scientific research.’”

The Vogel and Wise research labs are part of the Center for Drug Discovery, Design and Delivery (CD4) in Dedman College of Humanities and Sciences. The center’s mission is a novel multi-disciplinary focus for scientific research targeting medically important problems in human health. Their research is funded in part by the National Institutes of Health.

— Margaret Allen

> Read the full story at the SMU Research blog

Research: SMU study finds helicopter parenting harms boys and girls in different ways

Students Studying in Fondren Library CenterSMU researchers have found surprising gender differences in how college students react to misguided parenting. Their findings on the impact of helicopter parenting and fostering independence have been reported in a new article, “Helicopter Parenting, Autonomy Support, and College Students’ Mental Health and Well-being: The Moderating Role of Sex and Ethnicity,” in the Journal of Child and Family Studies.

Measuring both helicopter parenting as well as autonomy support — fostering independence — was important for the researchers to study, said family dynamics expert Chrystyna Kouros, SMU assistant professor of psychology and an author on the study.

“Just because mom and dad aren’t helicopter parents doesn’t necessarily mean they are supporting their young adult in making his or her own choices,” Kouros said. “The parent may be uninvolved, so we also wanted to know if parents are actually encouraging their student to be independent and make their own choices.”

The researchers found that young women are negatively affected by helicopter parenting, while young men suffer when parents don’t encourage independence.

“The sex difference was surprising,” said Kouros, an expert in adolescent depression. “In Western culture in particular, boys are socialized more to be independent, assertive and take charge, while girls are more socialized toward relationships, caring for others, and being expressive and compliant. Our findings showed that a lack of autonomy support — failure to encourage independence — was more problematic for males, but didn’t affect the well-being of females. Conversely, helicopter parenting — parents who are overinvolved — proved problematic for girls, but not boys.”

The study is unique in measuring the well-being of college students, said Kouros, director of SMU’s Family Health and Development Lab. The tendency in research on parenting has been to focus on the mental health of younger children.

“When researchers do focus on college students they tend to ask about academic performance, and whether students are engaged in school. But there haven’t been as many studies that look at mental health or well-being in relation to helicopter parenting,” she said.

Unlike children subjected to psychological control, in which parents try to instill guilt in their child, children of helicopter parents report a very close bond with their parents. Helicopter parents “hover” out of concern for their child, not from malicious intent, she said.

What helicopter parents don’t realize is that despite their good intentions to help their child, it actually does harm, said Naomi Ekas, a co-author on the study and assistant professor of psychology at Texas Christian University in Fort Worth.

“They’re not allowing their child to become independent or learn problem-solving on their own, nor to test out and develop effective coping strategies,” Ekas said.

Young men that reported more autonomy support, measured stronger well-being in the form of less social anxiety and fewer depressive symptoms.

For young women, helicopter parenting predicted lower psychological well-being. They were less optimistic, felt less satisfaction with accomplishments, and were not looking forward to things with enjoyment, nor feeling hopeful. In contrast, lacking autonomy support wasn’t related to negative outcomes in females.

“The take-away is we have to adjust our parenting as our kids get older,” said Kouros. “Being involved with our child is really important. But we have to adapt how we are involved as they are growing up, particularly going off to college.”

Other co-authors on the study are Romilyn Kiriaki and Megan Sunderland, SMU Department of Psychology, and Megan M. Pruitt, Texas Christian University. The study was funded by the Hogg Foundation for Mental Health at UT-Austin.

— Margaret Allen

> Read the full story from the SMU Research blog

Research: Hunting down cancer-causing viruses that hide from the immune system

Robert L. Harrod, Biology Lab ResearchSMU virologist and cancer researcher Robert L. Harrod has been awarded a $436,500 grant from the National Cancer Institute to further his lab’s research into how certain viruses cause cancers in humans.

Under two previous NCI grants, Harrod’s lab discovered that the human T-cell leukemia virus type-1, HTLV-1, and high-risk subtype human papillomaviruses, HPVs, share a common mechanism that plays a key role in allowing cancers to develop. Now the lab will search for the biological mechanism — a molecular target — to intervene to block establishment and progression of virus-induced cancers. The hope is to ultimately develop a chemotherapy drug to block the growth of those tumor cells in patients.

“The general theme of our lab is understanding the key molecular events involved in how the viruses allow cancer to develop,” said Harrod, an associate professor in SMU’s Department of Biological Sciences whose research focuses on understanding the molecular basis of viral initiation of cancer formation.

While HTLV-1 and HPV are unrelated transforming viruses and lead to very different types of cancers, they’ve evolved a similar mechanism to cooperate with genes that cause cancer in different cell types. The lab discovered that the two viruses tap a common protein that cooperates with cellular genes to help the viruses hide from the immune system.

That common protein, the p30 protein of HTLV-1, binds to a different protein in the cell, p53, which normally has the job of suppressing cancerous growth or tumor development. Instead, however, p30 manages to subvert p53’s tumor suppressor functions, which in turn activates pro-survival pathways for the virus.

From there, the virus can hide inside the infected cell for two to three decades while evading host immune-surveillance pathways. As the cell divides, the virus divides and replicates. Then ultimately the deregulation of gene expression by viral encoded products causes cancer to develop.

“They are essentially using a similar mechanism, p30, to deregulate those pathways from their normal tumor-suppressing function,” Harrod said.

— Margaret Allen

> Read more about Rob Harrod’s research at SMUResearch.com

Research: Computer model of key protein helps predict how cancer drugs will work

Drugs important in the battle against cancer behaved according to predictions when tested in a computer-generated model of P-glycoprotein, one of the cell’s key molecular pumps.

The new model allows researchers to dock nearly any drug in the P-gp protein and see how it will actually behave in P-gp’s pump, said Associate Professor John G. Wise, lead author on the journal article announcing the advancement and a faculty member in SMU’s Department of Biological Sciences, Dedman College of Humanities and Sciences.

SMU biologists developed the computer generated model to overcome the problem of relying on only static images for the structure of P-gp. The protein is the cellular pump that protects cells by pumping out toxins.

But that’s a problem when P-gp targets chemotherapy drugs as toxic, preventing chemo from killing cancer cells. Scientists are searching for ways to inhibit P-gp’s pumping action.

“The value of this fundamental research is that it generates dynamic mechanisms that let us understand something in biochemistry, in biology,” Wise said. “And by understanding P-gp in such detail, we can now think of ways to better and more specifically inhibit it.”

The SMU researchers tested Tariquidar, a new P-gp inhibitor still in clinical trials. Inhibitors offer hope for stopping P-gp’s rejection of chemotherapeutics by stalling the protein’s pumping action. Pharmacology researchers disagree, however, on where exactly Tariquidar binds in P-gp.

When run through the SMU model, Tariquidar behaved as expected: It wasn’t effectively pumped from the cell and the researchers observed that it prefers to bind high in the protein.

“Now we have more details on how Tariquidar inhibits P-gp, where it inhibits and what it’s actually binding to,” Wise said.

Written by Margaret Allen

> Read the full story from the SMU Research blog

Research: The speed secrets of super sprinters

The world’s fastest sprinters have unique gait features that account for their ability to achieve fast speeds, according to two new studies from SMU’s Annette Caldwell Simmons School of Education and Human Development.

The new findings indicate that the secret to elite sprinting speeds lies in the distinct limb dynamics sprinters use to elevate ground forces upon foot-ground impact.

“Our new studies show that these elite sprinters don’t use their legs to just bounce off the ground as most other runners do,” said human biomechanics expert Ken Clark, a researcher in the SMU Locomotor Performance Laboratory and lead author on the studies. “The top sprinters have developed a wind-up and delivery mechanism to augment impact forces. Other runners do not do so.”

The new findings address a major performance question that has remained unanswered for more than a decade. Previous studies had established that faster runners attain faster speeds by hitting the ground more forcefully than other runners do in relation to their body weight. However, how faster runners are able to do this was fully unknown. That sparked considerable debate and uncertainty about the best strategies for athletes to enhance ground-force application and speed.

“Elite speed athletes have a running pattern that is distinct,” Clark said. “Our data indicate the fastest sprinters each have identified the same solution for maximizing speed, which strongly implies that when you put the physics and the biology together, there’s only one way to sprint really fast.”

The critical and distinctive gait features identified by the study’s authors occur as the lower limb approaches and impacts the ground, said study co-author and running mechanics expert Peter Weyand, director of the Locomotor Performance Lab.

“We found that the fastest athletes all do the same thing to apply the greater forces needed to attain faster speeds,” Weyand said. “They cock the knee high before driving the foot into the ground, while maintaining a stiff ankle. These actions elevate ground forces by stopping the lower leg abruptly upon impact.”

The new research indicates that the fastest runners decelerate their foot and ankle in just over two-hundredths of a second after initial contact with the ground.

The findings are reported in the Journal of Applied Physiology in the article, “Are running speeds maximized with simple-spring stance mechanics?” It appears online at Physiology.org in advance of appearing in the print journal.

Written by Margaret Allen

> Read the full story at the SMU Research blog

Research: Fossil supervolcano discovered by SMU-led team
now part of new UNESCO Geopark

geopark“It is a rare event that geology is a catalyst of public cooperation and celebration,” says geologist and volcano expert Jim Quick, SMU’s associate vice president for research and dean of graduate studies.

The new Sesia-Val Grande Geopark is an example of just that, says Quick, whose international team in 2009 discovered a fossil supervolcano that now sits at the heart of the new geopark. The discovery sparked worldwide scientific interest and a regional geotourism industry.

Recently designated a geopark by the United Nations Educational, Scientific and Cultural Organization (UNESCO), the Sesia-Val Grande Geopark encompasses more than 80 communities in the Italian Alps.

The communities joined forces more than two years ago to promote the park’s creation, which UNESCO made official in September. The geopark spans tens of thousands of acres and has at its center the massive, 282 million-year-old fossil supervolcano.

“Sesia Valley is unique,” said Quick. “The base of the Earth’s crust is turned up on edge, exposing the volcano’s plumbing — which normally extends deep into the Earth and out of sight. The uplift was created when Africa and Europe began colliding about 30 million years ago and the crust of Italy was turned on end. We call this fossil the ‘Rosetta Stone’ for supervolcanoes because the depth to which rocks are exposed will aid scientific understanding of one of nature’s most massive and violent events and help us to link the geologic and geophysical data.”

The fossil supervolcano was discovered by Quick’s scientific team, which included scientists from Italy’s University of Trieste. The supervolcano has an unprecedented 15 miles of volcano plumbing exposed from the surface to the source of the magma deep within the Earth. Previously, the discovery record for exposed plumbing was about three miles, said Quick.

Only a handful of locations worldwide are chosen annually for UNESCO’s coveted geopark designation, which supports national geological heritage initiatives.

Written by Margaret Allen

> Read the full story at the SMU Research blog
> Visit the SMU Research and Graduate Studies homepage at smu.edu/research

Research: Depressed adolescents at risk for developing anxiety

Stock photo of pensive teenSome adolescents who suffer with symptoms of depression also may be at risk for developing anxiety, according to a new study of children’s mental health.

The study found that among youth who have symptoms of depression, the risk is most severe for those who have one or more of three risk factors, said SMU psychologist Chrystyna Kouros, who led the study.

Specifically, those who are most vulnerable are those who have a pessimistic outlook toward events and circumstances in their lives; those who have mothers with a history of an anxiety disorder; or those who report that the quality of their family relationships is poor, Kouros said.

A depressed adolescent with any one of those circumstances is more at risk for developing anxiety, the researchers found. The findings suggest that mental health professionals could target adolescents with those risk factors. Early intervention might prevent anxiety from developing, Kouros said.

“Depression or anxiety can be debilitating in itself,” said Kouros, an assistant professor of psychology in SMU’s Dedman College of Humanities and Sciences. “Combined, however, they are an even bigger threat to a child’s well-being. That’s particularly the case during adolescence, when pre-teens and teens are concerned about fitting in with their peers. Anxiety can manifest as social phobia, in which kids are afraid to interact with friends and teachers, or in school refusal, in which children try to avoid going to school.”

The findings are reported in Development and Psychopathology. The study, “Dynamic temporal relations between anxious and depressive symptoms across adolescence,” appears on the journal’s web site.

Kouros co-authored the research with psychiatrist Susanna Quasem and psychologist Judy Garber, both of Vanderbilt University. Data for the study were collected by Garber, a Vanderbilt professor of psychology and human development.

The finding was based on data from 240 children from metropolitan public schools and their mothers, all of whom were assessed annually for six years. The children were followed during the important developmental period from sixth grade through 12th grade. The study was evenly divided between boys and girls.

Consistent with previous research, the authors found also that “symptoms of anxiety were a robust predictor of subsequent elevations in depressive symptoms over time in adolescents.” That link has been known for some time, Kouros said, and the current study confirmed it.

Less well understood by researchers, however, has been the link between depressive symptoms developing further into elevated anxiety, she said.

“The current study showed that depressive symptoms were followed by elevations in anxious symptoms for a subset of youth who had mothers with a history of anxiety, reported low family relationship quality, or had a more negative attributional style,” the authors reported.

Written by Margaret Allen

> Read more at the SMU Research blog

Research: SMU students discover two new supernovae

SMU graduate student researchers have discovered two new supernovae, and their observations of these massive exploding stars will help improve the astronomical “tape measure” that scientists use to calculate the acceleration of the expansion of the universe.

A supernova discovered Wednesday, Feb. 6, 2013 exploded about 450 million years ago, said Farley Ferrante, a graduate student in the Department of Physics who made the initial observation.

The exploding star is in a relatively empty portion of the sky labeled “anonymous” in the faint constellation Canes Venatici. Home to a handful of galaxies, Canes Venatici is near the constellation Ursa Major, best known for the Big Dipper.

A second supernova discovered Tuesday, Nov. 20, 2012 exploded about 230 million years ago, said Ferrante, who made the initial observation. That exploding star is in one of the many galaxies of the Virgo constellation.

Both supernovae were spotted with the Robotic Optical Transient Search Experiment’s robotic telescope ROTSE3b, which is now operated by SMU graduate students. ROTSE3b is at the McDonald Observatory in the Davis Mountains of West Texas near Fort Davis.

The supernova that exploded about 450 million years ago is officially designated Supernova 2013X. It occurred when life on Earth consisted of creatures in the seas and oceans and along coastlines. Following naming conventions for supernovae, Supernova 2013X was nicknamed “Everest” by Govinda Dhungana, an SMU graduate student who participated in the discovery.

The supernova that exploded about 230 million years ago is officially designated Supernova 2012ha. The light from that explosion has been en route to Earth since the Triassic geologic period, when dinosaurs roamed the planet. “That’s fairly recent as these explosions go,” Ferrante said. Dhungana gave the nickname “Sherpa” to Supernova 2012ha.

Everest and Sherpa are two of about 200 supernovae discovered worldwide in a given year. Before telescopes, supernovae observations were rare — sometimes only several every few centuries, according to the scientists.

“Everest and Sherpa aren’t noteworthy for being the youngest, oldest, closest, furthest or biggest supernovae ever observed,” Ferrante said. “But both, like other supernovae of their kind, are important because they provide us with information for further science.”

Everest and Sherpa are Type 1a supernovae, the result of white dwarf explosions, said Robert Kehoe, physics professor and leader of the astronomy team in the Department of Physics.

The scientists explain that a white dwarf is a dying star that has burned up all its energy. It is about as massive as the Earth’s sun. Its core is about the size of the Earth. The core is dense, however, and one teaspoon of it weighs as much as Mount Everest, Kehoe said.

A white dwarf explodes if fusion restarts by tugging material from a nearby star, according to the scientists. The white dwarf grows to about one and a half times the size of the sun. Unable to support its weight, Kehoe said, collapse is rapid, fusion reignites and the white dwarf explodes. The result is a Type 1a supernova.

“We call these Type 1a supernovae standard candles,” Ferrante said. “Since Type 1a supernovae begin from this standard process, their intrinsic brightness is very similar. So they become a device by which scientists can measure cosmic distance. From Earth, we measure the light intensity of the exploded star. As star distances from Earth increase, their brilliance diminishes.”

While Sherpa is a standard Type 1a, Everest is peculiar. It exhibits the characteristics of a Type 1a called a 1991T, Ferrante said.

“Everest is the result of two white dwarfs that collide, then merge,” he said.

Like other Type 1a supernovae, Everest and Sherpa provide scientists with a tiny piece to the puzzle of one of the greatest mysteries of the universe: What is dark energy?

Every Type 1a supernova provides astronomers with indirect information about dark energy, which makes up 73 percent of the mass-energy in the universe. It’s theorized that dark energy explains the accelerating expansion of our universe at various epochs after the Big Bang.

“Every exploding star observed allows astronomers to more precisely calibrate the increasing speed at which our universe is expanding,” Ferrante said. “The older the explosion, the farther away, the closer it was to the Big Bang and the better it helps us understand dark energy.”

Written by Margaret Allen

> Read more from the SMU Research blog

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