The research, which appears today in The Astrophysical Journal Letters, was led by the University of Colorado Boulder and could help to shape the hunt for life beyond Earth’s solar system.

CU Boulder astrophysicist Meredith MacGregor explained that Proxima Centauri is a small but mighty star. It sits just four light-years or more than 20 trillion miles from our own sun and hosts at least two planets, one of which may look something like Earth. It’s also a “red dwarf,” the name for a class of stars that are unusually petite and dim.

Proxima Centauri has roughly one-eighth the mass of our own sun. But don’t let that fool you.

In their new study, MacGregor and her colleagues observed Proxima Centauri for 40 hours using nine telescopes on the ground and in space. In the process, they got a surprise: Proxima Centauri ejected a flare, or a burst of radiation that begins near the surface of a star, that ranks as one of the most violent seen anywhere in the galaxy.

“The star went from normal to 14,000 times brighter when seen in ultraviolet wavelengths over the span of a few seconds,” said MacGregor, an assistant professor at the Center for Astrophysics and Space Astronomy (CASA) and Department of Astrophysical and Planetary Sciences (APS) at CU Boulder.

The team’s findings hint at new physics that could change the way scientists think about stellar flares. They also don’t bode well for any squishy organism brave enough to live near the volatile star.

“If there was life on the planet nearest to Proxima Centauri, it would have to look very different than anything on Earth,” MacGregor said. “A human being on this planet would have a bad time.”

Active stars

The star has long been a target for scientists hoping to find life beyond Earth’s solar system. Proxima Centauri is nearby, for a start. It also hosts one planet, designated Proxima Centauri b, that resides in what researchers call the “habitable zone” — a region around a star that has the right range of temperatures for harboring liquid water on the surface of a planet.

But there’s a twist, MacGregor said: Red dwarves, which rank as the most common stars in the galaxy, are also unusually lively.

“A lot of the exoplanets that we’ve found so far are around these types of stars,” she said. “But the catch is that they’re way more active than our sun. They flare much more frequently and intensely.”

To see just how much Proxima Centauri flares, she and her colleagues pulled off what approaches a coup in the field of astrophysics: They pointed nine different instruments at the star for 40 hours over the course of several months in 2019. Those eyes included the Hubble Space Telescope, the Atacama Large Millimeter Array (ALMA) and NASA’s Transiting Exoplanet Survey Satellite (TESS). Five of them recorded the massive flare from Proxima Centauri, capturing the event as it produced a wide spectrum of radiation.

“It’s the first time we’ve ever had this kind of multi-wavelength coverage of a stellar flare,” MacGregor said. “Usually, you’re lucky if you can get two instruments.”

Crispy planet

The technique delivered one of the most in-depth anatomies of a flare from any star in the galaxy.

The event in question was observed on May 1, 2019 and lasted just 7 seconds. While it didn’t produce a lot of visible light, it generated a huge surge in both ultraviolet and radio, or “millimeter,” radiation.

“In the past, we didn’t know that stars could flare in the millimeter range, so this is the first time we have gone looking for millimeter flares,” MacGregor said.

Those millimeter signals, MacGregor added, could help researchers gather more information about how stars generate flares. Currently, scientists suspect that these bursts of energy occur when magnetic fields near a star’s surface twist and snap with explosive consequences.

In all, the observed flare was roughly 100 times more powerful than any similar flare seen from Earth’s sun. Over time, such energy can strip away a planet’s atmosphere and even expose life forms to deadly radiation.

That type of flare may not be a rare occurrence on Proxima Centauri. In addition to the big boom in May 2019, the researchers recorded many other flares during the 40 hours they spent watching the star.

“Proxima Centauri’s planets are getting hit by something like this not once in a century, but at least once a day if not several times a day,” MacGregor said.

The findings suggest that there may be more surprises in store from the sun’s closest companion.

“There will probably be even more weird types of flares that demonstrate different types of physics that we haven’t thought about before,” MacGregor said.

Using non-invasive research and no-flash camera traps from 2014 to 2019, scientists from Florida Atlantic University in collaboration with researchers from the FZS-Lomami Project, Democratic Republic of the Congo, now have picture-perfect details on this elusive species. They have confirmed the occurrence of the dryas monkey at seven locations in both Lomami National Park and its buffer zone spanning a total area of 3,453 square kilometers, based on opportunistic reports provided by local village residents and park patrols.

Their findings, published in Oryx — The International Journal of Conservation, indicate that Lomami National Park and its buffer zone contain the greatest extent of the species’ known range, and Lomami is the only national park with a confirmed population.

Although camera traps — a method for capturing wild animals on film when researchers are not present — are widely used to detect and survey cryptic species, the FAU scientists had to develop specific camera trap methods and placements to reliably detect the dryas monkeys.

Daniel Alempijevic, M.S., first author and a doctoral student at FAU, and Kate Detwiler, Ph.D., senior author and an associate professor in the Department of Anthropology in FAU’s Dorothy F. Schmidt College of Arts and Letters, developed a species-specific multi-strata (0 to 29 meters) camera-trap technique to detect the species with a placement of three camera traps at each survey point, one each monitoring the ground, understory and canopy.

Alempijevic positioned the camera traps on game paths (0.2 to 0.5 meters above ground), shrubs and liana tangles (1.5 to 10 meters), and horizontal limbs (14.9 to 29 meters) forming pathways to adjacent tree crowns. He used a single rope technique to access the canopy, and a double-rope technique to move to the desired camera-trap location when needed. With the solicited information on the dryas monkeys from the residents of villages, he selected specific sites for camera-trap surveillance.

“We selected Bafundo Forest in the buffer zone for camera-trap surveillance, starting at the location where the first reported dryas monkey was killed by a hunter,” said Detwiler. “We established the second survey site 40 kilometers west of Bafundo Village, at Camp Bartho in Lomami National Park after a ranger patrol team saw a dryas monkey there in 2014.”

Camera traps accumulated 1,742 trap days on the ground, 2,821 trap days in the understory and 2,927 trap days in the canopy. Understory camera traps recorded 32 dryas monkey events, canopy camera traps detected a single event, and dryas monkeys were not detected by camera traps at ground level. The cameras that detected the species most frequently were those in the lower strata of the canopy and understory, at 2 to 10 meters above ground. At least 365 trap days are required to achieve a 95 percent detection probability, although dryas monkeys may be detected sooner in suitable habitats.

“Our camera-trap placements detected dryas monkeys almost exclusively in the understory across all surveys, regardless of canopy structure, which supports our hypothesis that the species appear to prefer structurally complex understories and forest edges,” said Alempijevic. “Because our camera traps on the ground did not detect dryas monkeys, it seems unlikely that they travel on the ground. Only one camera trap in the canopy detected a dryas monkey, suggesting that they rarely travel in the upper canopy.”

The researchers note that high heterozygosity and low inbreeding measures from genomic analysis of a hunter-killed dryas monkey (collected on Oct. 26, 2014) from Bafundo Forest suggest that it was a representative of a larger contiguous population.

“We recommend that researchers and conservationists working in the central basin of the Democratic Republic of the Congo mobilize local knowledge to identify other areas where the dryas monkey occurs and confirm any reports using our species-specific camera-trap placement technique,” said Detwiler.

Study co-authors are John A. Hart, Ph.D., and Terese B. Hart, Ph.D., Frankfurt Zoological Society, FZS-Lomami Project, Democratic Republic of the Congo.

L’Institut Congolais pour la Conservation de la Nature granted research permission to work in Lomami National Park. The local chiefs of Bafundo, Likandjo and Bote villages and the Balanga sector chief of Maniema Province granted permission to access the forest.

Funding for this research was generously provided by the Margot Marsh Biodiversity Foundation, Mohammed Bin Zayed Species Conservation Fund, FAU, Primate Conservation Incorporated, the Lukuru Foundation, International Primatological Society, Dynamic Youth Community and Indigogo crowd funding.

The pulsar was detected with the Murchison Widefield Array (MWA) telescope, in Western Australia’s remote Mid West region.

It’s the first time scientists have discovered a pulsar with the MWA but they believe it will be the first of many.

The finding is a sign of things to come from the multi-billion-dollar Square Kilometre Array (SKA) telescope. The MWA is a precursor telescope for the SKA.

Nick Swainston, a PhD student at the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR), made the discovery while processing data collected as part of an ongoing pulsar survey.

“Pulsars are born as a result of supernovae — when a massive star explodes and dies, it can leave behind a collapsed core known as a neutron star,” he said.

“They’re about one and a half times the mass of the Sun, but all squeezed within only 20 kilometres, and they have ultra-strong magnetic fields.”

Mr Swainston said pulsars spin rapidly and emit electromagnetic radiation from their magnetic poles.

“Every time that emission sweeps across our line of sight, we see a pulse — that’s why we call them pulsars,” he said. “You can imagine it like a giant cosmic lighthouse.”

ICRAR-Curtin astronomer Dr Ramesh Bhat said the newly discovered pulsar is located more than 3000 light-years from Earth and spins about once every second.

“That’s incredibly fast compared to regular stars and planets,” he said. “But in the world of pulsars, it’s pretty normal.”

Dr Bhat said the finding was made using about one per cent of the large volume of data collected for the pulsar survey.

“We’ve only scratched the surface,” he said. “When we do this project at full-scale, we should find hundreds of pulsars in the coming years.”

Pulsars are used by astronomers for several applications including testing the laws of physics under extreme conditions.

“A spoonful of material from a neutron star would weigh millions of tonnes,” Dr Bhat said.

“Their magnetic fields are some of the strongest in the Universe — about 1000 billion times stronger than that we have on Earth.”

“So we can use them to do physics that we can’t do in any of the Earth-based laboratories.”

Finding pulsars and using them for extreme physics is also a key science driver for the SKA telescope.

MWA Director Professor Steven Tingay said the discovery hints at a large population of pulsars awaiting discovery in the Southern Hemisphere.

“This finding is really exciting because the data processing is incredibly challenging, and the results show the potential for us to discover many more pulsars with the MWA and the low-frequency part of the SKA.”

“The study of pulsars is one of the headline areas of science for the multi-billion-dollar SKA, so it is great that our team is at the forefront of this work,” he said.

The researchers computed air conditioning requirements in 60 of the world’s most populous cities — with the additional ventilation required due to COVID-19. Then, they compared the energy costs with their cooling method, using the chilled panels and natural ventilation.

The results, published in the COVID-19 edition of Applied Energy, showed that the alternative solution can save up to 45 per cent of the required energy, while ensuring building occupants are comfortable and rooms are adequately refreshed.

Dr. Adam Rysanek, a professor in the school of architecture and landscape architecture at UBC and co-author of the paper, notes that many public health guidelines, as well as building industry bodies, recommend increasing the flow of fresh, outdoor air into buildings in order to reduce the risk of spreading COVID-19 and other diseases.

“However, if we continue to rely on conventional HVAC systems to increase indoor fresh air rates, we may actually double energy consumption. That’s the nature of conventional HVAC.”

“Alternatively, we can encourage people to install new types of radiant cooling systems, which allow them to keep their windows open even when it’s hot outside. These alternative systems can provide a sufficient level of thermal comfort, increase protection against disease while lessening the impact on the environment,” noted Rysanek, director of the Building Decisions Research Group at UBC’s faculty of applied science.

Rysanek and his colleagues earlier demonstrated their cooling system in the hot and humid climate of Singapore. They built a public pavilion featuring a system of chilled tubes enclosed within a condensation-preventing membrane. This allowed occupants to feel comfortable, and even cold, without changing the air temperature surrounding the human body.

“You can think of it as lean A/C — or, even better, as a green alternative to energy-guzzling air conditioning,” said Rysanek.

Toronto is one of the cities included in the latest analysis, as are Beijing, Miami, Mumbai, New York and Paris. In all these regions, peak summer temperatures can soar past 35 degrees Celsius (95 degrees Fahrenheit).

“A key impact of climate change is the accelerating rise in average and peak temperatures, particularly in urban areas. We are expecting the appetite for indoor cooling will ramp up in the years ahead. Yet, if we want to mitigate urban heat and ensure people are healthy and comfortable while reducing our energy use, we need to seriously consider revolutionising our historical approach to air-conditioning,” adds Rysanek.

Rysanek notes that, though chilled panel systems have been around for decades, adding the special membrane devised by the research team could be the key to making it a commercially viable alternative to traditional HVAC systems in all climates.

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Little Foot’s shoulder assembly proved key to interpreting an early branch of the human evolutionary tree. Scientists at the Keck School of Medicine of USC focused on its so-called pectoral girdle, which includes collarbones, shoulder blades and joints.

Although other parts of Little Foot, especially its legs, show humanlike traits for upright walking, the shoulder components are clearly apelike, supporting arms surprisingly well suited for suspending from branches or shimmying up and down trees rather than throwing a projectile or dangling astride the torso like humans.

The Little Foot fossil provides the best evidence yet of how human ancestors used their arms more than 3 million years ago, said Kristian J. Carlson, lead author of the study and associate professor of clinical integrative anatomical sciences at the Keck School of Medicine.

“Little Foot is the Rosetta stone for early human ancestors,” he said. “When we compare the shoulder assembly with living humans and apes, it shows that Little Foot’s shoulder was probably a good model of the shoulder of the common ancestor of humans and other African apes like chimpanzees and gorillas.”

The apelike characteristics will likely attract considerable intrigue as science teams around the world have been examining different parts of the skeleton to find clues to human origins. The USC-led study, which also involved researchers at the University of Wisconsin, the University of Liverpool and the University of the Witwatersrand in South Africa, among others, was published today in the Journal of Human Evolution.

The journal devoted a special issue to Little Foot analyses from a global research group, which looked at other parts of the creature’s skeleton. The process is somewhat akin to the story of blind men and the elephant, each examining one part in coordination with others to explain the whole of something that’s not fully understood.

The Little Foot fossil is a rare specimen because it’s a near-complete skeleton of an Australopithecus individual much older than most other human ancestors. The creature, probably an old female, stood about 4 feet tall with long legs suitable for bipedal motion when it lived some 3.67 million years ago. Called “Little Foot” because the first bones recovered consisted of a few small foot bones, the remains were discovered in a cave in South Africa in the 1990s. Researchers have spent years excavating it from its rock encasement and subjecting it to high-tech analysis.

While not as widely known as the Lucy skeleton, another Australopithecus individual unearthed in East Africa in the 1970s, Carlson said Little Foot is older and more complete.

The USC-led research team zeroed in on the shoulder assemblies because Little Foot provides the oldest and most intact example of this anatomy ever found. Those bones provide telltale clues of how an animal moves. In human evolution, he said, these parts had to change form before our ancestors could live life free of trees, walk the open savannah and use their arms for functions other than supporting the weight of the individual.

The scientists compared the creature’s shoulder parts to apes, hominins and humans. Little Foot was a creature adapted to living in trees because the pectoral girdle suggests a creature that climbed trees, hung below branches and used its hands overhead to support its weight.

For example, the scapula, or shoulder blade, has a big, high ridge to attach heavy muscles similar to gorillas and chimpanzees. The shoulder joint, where the humerus connects, sits at an oblique angle, useful for stabilizing the body and lessening tensile loads on shoulder ligaments when an ape hangs beneath branches. The shoulder also has a sturdy, apelike reinforcing structure, the ventral bar. And the collarbone has a distinctive S-shaped curve commonly found in apes.

Those conclusions mean that the structural similarities in the shoulder between humans and African apes are much more recent, and persisted much longer, than has been proposed, Carlson said.

“We see incontrovertible evidence in Little Foot that the arm of our ancestors at 3.67 million years ago was still being used to bear substantial weight during arboreal movements in trees for climbing or hanging beneath branches,” he said. “In fact, based on comparisons with living humans and apes, we propose that the shoulder morphology and function of Little Foot is a good model for that of the common ancestor of humans and chimpanzees 7 million to 8 million years ago.”

The scientists were able to achieve remarkably clear images of the fossils. That’s because the bones, painstakingly excavated for many years, are in good condition and uniquely complete. The scientists examined them using micro-CT scans, which can detect minute features on the surface of an object, peer deep inside a bone, measure the density of an object and generate a 3D model without harming the fossil.

Using a new approach to ice-penetrating radar data, Stanford University scientists show that this melting left behind a contiguous layer of refrozen ice inside the snowpack, including near the middle of the ice sheet where surface melting is usually minimal. Most importantly, the formation of the melt layer changed the ice sheet’s behavior by reducing its ability to store future meltwater. The research appears in Nature Communications April 20.

“When you have these extreme, one-off melt years, it’s not just adding more to Greenland’s contribution to sea-level rise in that year — it’s also creating these persistent structural changes in the ice sheet itself,” said lead study author Riley Culberg, a PhD student in electrical engineering. “This continental-scale picture helps us understand what kind of melt and snow conditions allowed this layer to form.”

The 2012 melt season was caused by unusually warm temperatures exacerbated by high atmospheric pressure over Greenland — an extreme event that may have been caused or intensified by climate change. The Greenland Ice Sheet has experienced five record-breaking melt seasons since 2000, with the most recent occurring in 2019.

“Normally we’d say the ice sheet would just shrug off weather — ice sheets tend to be big, calm, slow things,” said senior author Dustin Schroeder, an assistant professor of geophysics at Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth). “This is really one of the first cases where you can say, shockingly, in some ways, these slow, calm ice sheets care a lot about a single extreme event in a particularly warm year.”

Shifting scenarios

Airborne radar data, a major expansion to single-site field observations on the icy poles, is typically used to study the bottom of the ice sheet. But by pushing past technical and computational limitations through advanced modeling, the team was able to reanalyze radar data collected by flights from NASA’s Operation IceBridge from 2012 to 2017 to interpret melt near the surface of the ice sheet, at a depth up to about 50 feet.

“Once those challenges were overcome, all of a sudden, we started seeing meltwater ice layers near the surface of the ice sheet,” Schroeder said. “It turns out we’ve been building records that, as a community, we didn’t fully realize we were making.”

Melting ice sheets and glaciers are the biggest contributors to sea-level rise — and the most complex elements to incorporate into climate model projections. Ice sheet regions that haven’t experienced extreme melt can store meltwater in the upper 150 feet, thereby preventing it from flowing into the ocean. A melt layer like the one from 2012 can reduce the storage capacity to about 15 feet in some parts of the Greenland Ice Sheet, according to the research.

The type of melt followed by rapid freeze experienced in 2012 can be compared to wintry conditions in much of the world: snow falls to the ground, a few warm days melt it a little, then when it freezes again, it creates slick ice — the kind that no one would want to drive on.

“The melt event in 2012 is impacting the way the ice sheet responds to surface melt even now,” Culberg said. “These structural changes mean the way the ice sheet responds to surface melting is going to be impacted longer term.”

In the long run, meltwater that can no longer be stored in the upper part of the ice sheet may drain down to the ice bed, creating slippery conditions that speed up the ice and send chunks into the ocean, raising sea levels more quickly.

Polar patterns

Greenland currently experiences change much more rapidly than its South Pole counterpart. But lessons from Greenland may be applied to Antarctica when the seasons shift, Schroeder said.

“I think now there’s no question that when you’re trying to project into the future, a warming Antarctic will have all these processes,” Schroeder said. “If we don’t use Greenland now to better understand this stuff, our capacity to understand how a warmer world will be is not a hopeful proposition.”

The research was supported by a National Defense Science and Engineering Graduate Fellowship and the National Science Foundation (NSF).

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Materials provided by Stanford University. Original written by Danielle Torrent Tucker. Note: Content may be edited for style and length.