Category: Science

TAMPA, Fla. —Iridium unveiled chip maker Qualcomm Jan. 5 as the partner behind plans to connect smartphones to its satellite constellation this year.

U.S.-based Qualcomm has developed a product called Snapdragon Satellite, which it said can be added to Android smartphones and other devices to support two-way communications via Iridium satellites.

Potential uses include emergency SOS services, SMS texts, and other low-bandwidth messaging applications in areas outside terrestrial networks and where Iridium’s global constellation is licensed to operate.

Any emergency messages would be routed through response teams run by Garmin, a GPS technology specialist and longtime Iridium partner.

Jordan Hassin, Iridium’s executive director of communication, acknowledged widespread speculation in the run-up to the announcement about South Korean smartphone maker Samsung being its direct-to-smartphone partner.

At one point Iridium was also rumored to be working with Apple, which in September announced a partnership with Iridium’s rival Globalstar for services currently limited to SOS.

However, rather than partnering with a specific smartphone vendor, Hassin said Iridium chose to team up with Qualcomm to enable its technology in multiple smartphone brands that run Android, the most popular operating system for mobile phones.

In addition to supporting hardware development, Qualcomm has an agreement to sell the service to companies on Iridium’s behalf.

Qualcomm’s chipsets are already commonly used in Samsung, Motorola, and other smartphone brands worldwide. 

To connect to Iridium’s 66-strong constellation in low Earth orbit, smartphone makers would need to integrate the latest generation of a Qualcomm chipset that is geared toward premium phones.

Hassin said “several” Android customers are already integrating Snapdragon Satellite, with the first products expected to be released in the second half of 2023.

In a media briefing, Iridium CEO Matt Desch said it is still “being worked out” how and if smartphone customers would be charged for using its satellite-enabled services.

Apple has said it will offer satellite-enabled SOS services on its range of iPhone 14 smartphones for free for two years.

Francesco Grilli, vice president of product management at Qualcomm Technologies, told the briefing the company successfully demonstrated Snapdragon Satellite Jan. 4 in Las Vegas as part of the Consumer Electronics Show (CES).

He said the company was able to send basic text messages in an average of three seconds with a smartphone during the demo. 

While the service will initially target smartphones, the companies said they are considering expanding to other devices, including laptops, tablets, vehicles, and small Internet of Things machines.

Desch said the company could also consider upgrading its capabilities to add higher bandwidth services later, in line with other businesses that are also looking to enter the direct-to-smartphone market.

“We certainly have aspirations to go well beyond where we are today,” he said.

In addition to Apple and Globalstar, other companies seeking to provide direct-to-smartphone services from LEO include SpaceX in partnership with T-Mobile, AST SpaceMobile, Lynk Global, and Sateliot.

In July, Qualcomm announced plans with Swedish telecoms equipment maker Ericsson and French aerospace company Thales to demonstrate 5G on smartphones via LEO satellites.

However, Grilli said these plans are still in the research and development phase, and any commercial services would require spectrum and hundreds of new satellites to become a reality.

He said it is unlikely Qualcomm’s venture with Ericsson and Thales would “see any product before 2026 at the earliest,” and that is optimistic.

TAMPA, Fla. — Canada’s NorthStar Earth and Space said Jan. 5 it has raised $35 million ahead of plans to deploy its first three satellites this year for tracking objects in orbit.

U.S.-based private equity firm Cartesian Capital led the Series C funding round, which NorthStar CEO Stewart Bain said brings the total amount the company has raised to nearly $100 million.

NorthStar aims to use proceeds to accelerate plans for a constellation of 24 Space Situational Awareness (SSA) satellites, which would scan out from low Earth orbit (LEO) to track other satellites and debris. 

The company hopes to track objects as small as one centimeter in LEO, about seven centimeters in medium Earth orbit (MEO) and “somewhere between 50 and 40” centimeters even farther out in geostationary orbit (GEO), Bain said in an interview.

Spire Global is building the first three satellites for NorthStar, each the size of 16 cubesats, for a launch around the middle of 2023 with Virgin Orbit.

Bain said it had not been decided whether these satellites would be deployed from Virgin Orbit’s base in California, or be part of the air-launch company’s first batch of missions from England.

NorthStar’s contract with Spire includes options for up to 30 satellites, and Bain said the company is now looking at “when to pull the trigger” on the next set of spacecraft.

“It’ll probably be another set of three,” he said, “and then after that we’ll probably do them in blocks of six.”

There “is an argument to be made of letting the first few get up, see how they operate, and then pushing the button on the next set,” he added, “or leading that by a certain amount of time” to help ensure the timely delivery of parts amid the industry’s supply chain issues.

The first three satellites have already secured commitments from a mix of commercial and government customers, according to Bain, although he declined to disclose them.

He said a U.S. government pilot project that picked NorthStar and five other commercial firms in December to prototype space traffic data platforms helped highlight commercial SSA opportunities and attract business.

“It’s not like we weren’t already contacting both government and private sector operators,” he said, “but that really got people to wake up and say, wow, here we go.”

Luxembourg-based satellite operator SES last year announced plans to use NorthStar’s data to help manage its fleet of satellites in GEO and MEO.

Bain said a space development fund supported by SES and Luxembourg’s government participated in NorthStar’s Series C funding round.

Other investors included the government of Quebec and a family-owned Canadian technology fund called Telesystem Space.

A semi-submersible vehicle may prove that the best way to travel undetected and efficiently in water is not on top, or below, but in between.

The roughly 1.5-foot-long semi-sub prototype, built with off-the-shelf and 3D-printed parts, showed its seaworthiness in water tests, moving quickly with low drag and a low profile.

The researchers detailed the test results in a study in the journal Unmanned Systems.

This vessel-type isn’t new. Authorities have discovered crudely made semi-subs being used for illicit purposes in recent years, but researchers aim to demonstrate how engineer-developed half-submerged vessels can efficiently serve military, commercial, and research purposes.

“A semi-submersible vehicle is relatively inexpensive to build, difficult to detect, and it can go across oceans,” says Konstantin Matveev, a professor of engineering at Washington State University who led the work.

“It’s not so susceptible to waves in comparison to surface ships since most of the body is underwater, so there are some economic advantages as well.”

Since the semi-sub sails mostly at the water line, it does not need to be made of as strong materials as a submarine which has to withstand the pressure of being underwater for long periods of time. The semi-sub also has the advantage of having a small platform in contact with the atmosphere, making it easier to receive and transmit data.

For this study, Matveev and coauthor Pascal Spino, a recent Washington State graduate, piloted the semi-sub in Snake River’s Wawawai Bay in Washington state. They tested its stability and ability to maneuver.

The semi-sub reached a max speed of 1.5 meters per second (roughly 3.4 miles an hour), but at higher speeds, it rises above the water creating more of a wake and expending more energy. At lower speeds, it is almost fully immersed and barely makes a ripple.

The researchers also outfitted the semi-sub with sonar and mapped the bottom of a reservoir near Pullman, Washington to test its ability to collect and transmit data.

While not yet completely autonomous, the semi-sub can be pre-programmed to behave in certain ways, such as running a certain route by itself or responding to particular objects by pursuing them or running away.

While the semi-sub is relatively small at 450 mm long with a 100 mm diameter (about 1.5 foot long and 4 inches in diameter), Matveev says it is possible for larger semi-subs to be built to carry significant cargo. For instance, they could be used to help refuel ships or stations at sea. They could even be scaled up to rival container ships, and since they experience less drag in the water, they would use less fuel creating both an environmental and economic advantage.

For now, Matveev’s lab is continuing work on optimizing the shape of semi-submersible vehicle prototypes to fit specific purposes. He is currently collaborating with the US Naval Academy in Annapolis, Maryland to work on the vehicles’ operational capabilities and compare numerical simulations with results from experiments.

Source: Washington State University

A new type of active pixel sensor that uses a novel 2D-material may enable ultra-sharp cell phone photos and create a new class of extremely energy-efficient Internet of Things sensors, researchers say.

“When people are looking for a new phone, what are the specs that they are looking for?” says Saptarshi Das, associate professor of engineering science and mechanics at Penn State and lead author of the paper in Nature Materials.

“Quite often, they are looking for a good camera, and what does a good camera mean to most people? Sharp photos with high resolution.”

Most people just snap a photo of a friend, a family gathering, or a sporting event, and never think about what happens “behind the scenes” inside the phone when one snaps a picture. There is quite a bit happening to enable you to see a photo right after you take it, and this involves image processing, Das says.

“When you take an image, many of the cameras have some kind of processing that goes on in the phone, and in fact, this sometimes makes the photo look even better than what you are seeing with your eyes. These next generation of phone cameras integrate image capture with image processing to make this possible, and that was not possible with older generations of cameras.”

However, the great photos in the newest cameras have a catch—the processing requires a lot of energy.

“There’s an energy cost associated with taking a lot of images,” says Akhil Dodda, a graduate research assistant at Penn State at the time of the study who is now a research staff member at Western Digital, and co-first author of the study.

“If you take 10,000 images, that is fine, but somebody is paying the energy costs for that. If you can bring it down by a hundredfold, then you can take 100 times more images and still spend the same amount of energy. It makes photography more sustainable so that people can take more selfies and other pictures when they are traveling. And this is exactly where innovation in materials comes into the picture.”

Low light phone photos

The innovation in materials outlined in the study revolves around how the researchers added in-sensor processing to active pixel sensors to reduce their energy use. So, they turned to a novel 2D material, which is a class of materials only one or a few atoms thick, molybdenum disulfide. It is also a semiconductor and sensitive to light, which makes it ideal as a potential material to explore for low-energy in-sensor processing of images.

“We found that molybdenum disulfide has very good photosensitive response,” says Darsith Jayachandran, graduate research assistant in engineering and mechanics and co-first author of the study. “From there, we tested it for the other properties we were looking for.”

These properties included sensitivity to low light, which is important for the dynamic range of the sensor. The dynamic range refers to the ability to “see” objects in both low light such as moonlight and bright light such as sunlight. The human eye can see stars at night better than most cameras due to having superior dynamic range.

Molybdenum disulfide also demonstrated strong signal conversion, charge-to-voltage conversion and data transmission capabilities. This makes the material an ideal candidate to enable an active pixel sensor that can do both light sensing and in-sensor image processing.

“From there, we put the sensors into an array,” Jayachandran says. “There are 900 pixels in a nine square millimeter array we developed, and each pixel is about 100 micrometers. They are much more sensitive to light than current CMOS sensors, so they do not require any additional circuitry or energy use. So, each pixel requires much less energy to operate, and this would mean a better cell phone camera that uses a lot less battery.”

Internet of Things benefits

The dynamic range and image processing would enable users to take sharp photos in a variety of adverse conditions for photography, according to Das.

“For example, you could take clearer photos of friends outside at night or on a rainy or foggy day,” Das says. “The camera could do denoising to clear up the fog and the dynamic range would enable say a night photo of a friend with stars in the background.”

Along with enabling a top-rate phone camera in the future, the team also envisions their improved sensor technology could have other applications. This would include better light sensors for Internet of Things (IoT) and Industry 4.0 applications.

Industry 4.0 is the term for a growing movement that combines traditional industry practices and cutting-edge digital technology such as the Internet of Things, cloud data storage, and artificial intelligence/machine learning. The goal is to improve manufacturing by developing more efficient processes and practices through intelligent automation, and sensors are key.

“Sensors that can see through machines while in operation and identify defects are very important in the IoT,” Dodda says. “Conventional sensors consume a lot of energy so that is a problem, but we developed an extremely energy efficient sensor that enables better machine learning, etc. and saves a lot in energy costs.”

The Department of Defense and the National Science Foundation supported the work.

Source: Penn State

Does COVID change the body’s response to other threats? Depends on your sex, research indicates.

The long-term effects of infection on the immune system have long intrigued immunobiologist John Tsang. After the body has faced down a pathogen, does the immune system return to the previous baseline? Or does a single infection change it in ways that alter how it will respond not only to a familiar virus but also to the next new viral or bacterial threat it faces?

Tsang, a professor of immunobiology and biomedical engineering at Yale University, has long believed that the immune system reverts to the previous stable baseline after viral infection.

The emergence of the COVID-19 pandemic in 2020 allowed him and colleagues to test that theory. The answer, they find, depends on the individual’s sex, according to a study in the journal Nature.

For the study, a team led by Tsang, who at the time was at the National Institute of Allergy and Infectious Diseases (NIAID), and colleagues, including lead author Rachel Sparks, also from NIAID, systematically analyzed immune responses of healthy people who had received the flu vaccine. From that data, they then compared the responses between those who had never been infected by SARS-CoV-2, the virus that causes COVID-19, and those who experienced mild cases but recovered.

To their surprise, they found that the immune systems of men who had recovered from mild cases of COVID-19 responded more robustly to flu vaccines than women who had had mild cases or men and women who had never been infected.

In essence, the baseline immune statuses in men previously infected with SARS-CoV-2 was altered in ways that changed the response to an exposure different from SARS-CoV-2, the authors say.

“This was a total surprise,” Tsang says. “Women usually mount a stronger overall immune response to pathogens and vaccines, but are also more likely to suffer from autoimmune diseases.”

The findings may also be linked to an observation made early in the pandemic: Men were much more likely to die from a runaway immune response than women after contracting the COVID-19 virus. Even mild cases of COVID-19, the new findings suggest, might trigger stronger inflammatory responses in males than females, resulting in more pronounced functional changes to the male immune system, even long after recovery.

Their unbiased analysis of immune system status down to the individual cell level reveals several differences between COVID-recovered males and healthy controls and COVID-recovered females, both before and after receiving flu vaccinations. For instance, previously infected males produced more antibodies to influenza and produced increased levels of interferons, which are produced by cells in response to infections or vaccines. Generally, healthy females have stronger interferon responses than their male counterparts.

Understanding the lingering effects of COVID-19 on the immune system is crucial, the authors say, since more than 600 million people worldwide have been infected so far, and the emergence of “long-COVID” symptoms in some people continues to be a major health concern.

“Our findings point to the possibility that any infection or immune challenge may change the immune status to establish new set points,” says Sparks. “The immune status of an individual is likely shaped by a multitude of prior exposures and perturbations.”

Tsang thinks these findings may also help scientists create better vaccines against diverse threats by, for instance, mimicking how mild COVID-19 changes the male immune baseline.

Source: Yale University

The Oracle spacecraft will carry an optical payload made by Leidos and AFRL’s green propellant experiment for a two-year demonstration

WASHINGTON — General Atomics Electromagnetic Systems won a contract from Advanced Space to build a satellite that the Air Force Research Laboratory plans to launch to deep space in 2025.

General Atomics, based in San Diego, California, announced Jan. 5 it will produce an ESPA-class satellite bus, integrate and test payloads for Advanced Space, the prime contractor for AFRL’s Oracle experiment. 

AFRL’s Space Vehicles Directorate in November awarded Advanced Space a $72 million contract to develop a spacecraft for the Oracle mission, intended to monitor deep space, far beyond Earth’s orbit. 

The Oracle spacecraft will carry an optical payload made by Leidos and AFRL’s green propellant experiment for a two-year demonstration. 

 Oracle will seek to detect objects and demonstrate spacecraft positioning and navigation techniques far beyond geosynchronous Earth orbit, in the vicinity of Earth-moon Lagrange Point 1, about 200,000 miles from Earth. The GEO belt is about 22,000 miles above Earth.

Scott Forney, president of GA-EMS, said the platform selected for Oracle, the ESPA Grande, is a modular ring shaped bus that the company also is using to build a weather imaging satellite for the U.S. Space Force.

“The AFRL Oracle spacecraft program is intended to demonstrate advanced techniques to detect and track objects in the region near the Moon that cannot be viewed optically from the Earth or from satellites in traditional orbits,” he said in a statement.

Gregg Burgess, vice president of GA-EMS space systems, said the cislunar region “continues to be a strategic area of focus for us.” The company in 2021 won a $22 million contract from the Defense Advanced Research Projects Agency to design a small nuclear reactor for a demonstration of nuclear thermal propulsion in cislunar space.

Genetically engineered mitochondria can convert light energy into chemical energy that cells can use, ultimately extending the life of the roundworm C. elegans, a new study shows.

While the prospect of sunlight-charged cells in humans is more science fiction than science, the research, which takes a page from the field of renewable energy, sheds light on important mechanisms in the aging process.

“We know that mitochondrial dysfunction is a consequence of aging,” says Andrew Wojtovich, associate professor of anesthesiology and perioperative medicine and pharmacology and physiology at the University of Rochester Medical Center, as well as senior author of the study in Nature Aging.

“This study found that simply boosting metabolism using light-powered mitochondria gave laboratory worms longer, healthier lives. These findings and new research tools will enable us to further study mitochondria and identify new ways to treat age-related diseases and age healthier.”

Mitochondria are organelles found in most cells in the body. Often referred to as cellular power plants, mitochondria use glucose to produce adenosine triphosphate (ATP), the compound that provides energy for key functions in the cell, such as muscle contraction and the electrical impulses that help nerve cells communicate with each other.

Production of ATP is the result of a number of reactions made possible by the exchange of protons across a membrane that separates different compartments in mitochondria, the efficiency with which this occurs is called membrane potential. Known to decline with age, membrane potential is a topic of great interest in the scientific community because of its potential role in a number of age-related diseases, such as neurodegenerative disorders.

The new research involved C. elegans, a microscopic roundworm that—like the fruit fly Drosophila—has long been a research tool used by scientists to understand basic biological principles that, in many cases, apply throughout the animal kingdom.

To carry out the experiments, a team of researchers turned to optogenetics, a research tool that uses light to control biological processes within cells. Neuroscientists use optogenetics to target and activate specific neurons to study patterns of brain activity. The tool allowed the researchers to target and manipulate activity in C. elegans mitochondria—a task made easier by the fact that the worms are transparent.

The researchers genetically engineered C. elegans mitochondria to include a light-activated proton pump obtained from a fungus, an achievement the team first described in a 2020 paper in the journal EMBO Reports.

In the new study, when exposed to light, the proton pumps moved charged ions across the membrane, using the energy from the light to charge the mitochondria. This process, which the researchers dubbed mitochondria-ON (mtON), increased membrane potential and ATP production, and resulted in a 30-40% increase in lifespan of the roundworms.

“Mitochondria are similar to industrial power plants in that they combust a source of carbon, primarily glucose, to produce useful energy for the cell,” says first author Brandon Berry, who received his doctoral degree in physiology from the University of Rochester and is now a postdoctoral scholar at the University of Washington.

“What we have done is essentially hooked up a solar panel to the existing power plant infrastructure. In this instance, the solar panel is the optogenetic tool mtON. The normal mitochondrial machinery is then able to harness the light energy to provide the ATP in addition to the normal combustion pathway.”

The study is important because it provides researchers with more insight into the complex biological roles that mitochondria play in the human body, a topic that the scientific community is only now beginning to understand. The study also creates a new method to manipulate and study mitochondria in the environment of a living cell. This could serve as an important platform to study mitochondria and identify ways to intervene and support function.

“We need to understand more about how mitochondria truly behave in an animal,” says Berry. “First in worms, like the current study, but then in human cells in culture and in rodents. That way future research will be well informed to target the most likely players in human disease and aging.”

Additional coauthors are from the University of Rochester; the University of Washington; and the Research Institute for Farm Biology and Technical University of Munich, both in Germany. The National Institutes of Health and a Longevity Impetus Grant funded the work.

Source: University of Rochester

Researchers have created a map of oceanic “dead zones” that existed during the Pliocene epoch, when the Earth’s climate was two to three degrees warmer than it is now.

The work could provide a glimpse into the locations and potential impacts of future low oxygen zones in a warmer Earth’s oceans.

Oxygen minimum zones, or OMZs, are areas in the ocean where oxygen levels in the mid-waters (from 100 to 1,000 meters below the surface) are too low to support most marine life. These dead zones play an important role in the ocean’s overall health.

“OMZs are very important for geochemical cycling in the ocean,” says Catherine Davis, assistant professor of marine, earth and atmospheric sciences at North Carolina State University and corresponding author of the research in Nature Communications.

“They occur in areas where sunlight and atmospheric oxygen don’t reach. Their locations dictate where carbon and nitrogen (an essential nutrient for all life on Earth) are available in the ocean—so they’re important drivers of nutrient cycles.”

Being able to predict the location of OMZs is important not only for understanding nutrient cycling, but also because of their effects on marine life. Oceanic dead zones restrict the range of animals to the shallow surface ocean where oxygen is more plentiful.

Davis and her colleagues wanted to figure out how a warmer climate might impact future OMZs. So they looked to the Pliocene epoch, (5.3 to 2.6 million years ago) when the Earth’s atmospheric CO2 levels were close to what they are now.

“The Pliocene is the last time that we had a stable, warm climate globally, and the average global temperature was 2 C to 3 C warmer than it is now—which is what scientists predict could be the case in about 100 years,” Davis says.

To determine where Pliocene OMZs were located, the researchers used tiny fossilized plankton called foraminifera. Foraminifera are single-celled organisms about the size of a large grain of sand. They form hard, calcium carbonate shells, which can stay in marine sediments.

One species in particular—Globorotaloides hexagonus—is found only in low oxygen zones. By combing through databases of Pliocene sediments to locate that species, the team was able to map Pliocene OMZs. They overlaid their map onto a computer model of Pliocene oxygen levels, and found that the two agreed with each other.

The OMZ map shows that during the Pliocene, low-oxygen waters were much more widespread in the Atlantic Ocean—particularly in the North Atlantic. The North Pacific, on the other hand, had fewer low-oxygen areas.

“This is the first global spatial reconstruction of oxygen minimum zones in the past,” Davis says. “And it’s in line with what we’re already seeing in the Atlantic in terms of lower oxygen levels. Warmer water holds less oxygen. This dead zone map from the Pliocene could give us a glimpse into what the Atlantic might look like 100 years from now on a warmer Earth.”

What would a future with much less oxygen in the Atlantic mean? According to Davis, it could have a big impact on everything from carbon storage and nutrient cycling in the ocean to how fisheries and marine species are managed.

“OMZs act as a ‘floor’ for marine animals—they get squished to the surface,” Davis says. “So fishermen may suddenly see a lot of fish, but it doesn’t mean that there are actually more than normal—they’re just being forced into a smaller space. Fisheries will need to take the effects of OMZs into account when managing populations.

“We may also see subtle but far-reaching changes concerning the amounts of nutrients available for life in those surface waters, as well as where CO2 taken up by the ocean is stored.”

Davis began the research while a postdoctoral researcher at Yale University. Additional coauthors are from Yale, George Mason University, NASA, and NC State.

The National Science Foundation supported the work.

Source: NC State

New research on the Indian Ocean dipole shows how melting ice water from massive glaciers can ultimately lead to droughts and flooding in East Africa and Indonesia.

With a new analysis of long-term climate data, researchers say they now have a much better understanding of how climate change can cause sea water temperatures on one side of the Indian Ocean to be so much warmer or cooler than the temperatures on the other—a phenomenon that can lead to sometimes deadly weather-related events like megadroughts in East Africa and severe flooding in Indonesia.

The analysis, described in a new study in Science Advances, compares 10,000 years of past climate conditions reconstructed from different sets of geological records to simulations from an advanced climate model.

The findings show that about 18,000 to 15,000 years ago, as a result of melted freshwater from the massive glacier that once covered much of North America pouring into the North Atlantic, ocean currents that kept the Atlantic Ocean warm weakened, setting off a chain of events in response. The weakening of the system ultimately led to the strengthening of an atmospheric loop in the Indian Ocean that keeps warmer water on one side and cooler water on the other.

This extreme weather pattern, known as a dipole, prompts one side (either east or west) to have higher-than-average rainfall and the other to have widespread drought. The researchers saw examples of this pattern in both the historical data they studied and the model’s simulation. They say the findings can help scientists not only better understand the mechanisms behind the east-west dipole in the Indian Ocean, but also one day help to produce more effective forecasts of drought and flood in the region.

“We know that in the present-day gradients in the temperature of the Indian Ocean are important to rainfall and drought patterns, especially in East Africa, but it’s been challenging to show that those gradients change on long time-scales and to link them to long-term rainfall and drought patterns on both sides of the Indian Ocean,” says James Russell, a study author and professor of earth, environmental, and planetary sciences at Brown. “We now have a mechanistic basis to understand why some of the longer-term changes in rainfall patterns in the two regions have changed through time.”

Indian Ocean dipole

In the paper, the researchers explain the mechanisms behind how the Indian Ocean dipole they studied formed and the weather-related events it led to during the period they looked at, which covered the end of the last Ice Age and the start of the current geological epoch.

The researchers characterize the dipole as an east-west dipole where the water on the western side—which borders modern day East African countries like Kenya, Ethiopia, and Somalia—is cooler than the water on eastern side toward Indonesia. They saw that the warmer water conditions of the dipole brought greater rainfall to Indonesia, while the cooler water brought much drier weather to East Africa.

That fits into what is often seen in recent Indian Ocean dipole events. In October, for example, heavy rain led to floods and landslides in Indonesian islands of Java and Sulawesi, leaving four people dead and affecting over 30,000 people. On the opposite end, Ethiopia, Kenya, and Somalia experienced intense droughts starting in 2020 that threatened to cause famine.

The changes the authors observed 17,000 years ago were even more extreme, including the complete drying of Lake Victoria—one of the largest lakes on Earth.

“Essentially, the dipole intensifies dry conditions and wet conditions that could result in extreme events like multi-year or decades-long dry events in East Africa and flooding events in South Indonesia,” says Xiaojing Du, a postdoctoral researcher in the Institute at Brown for Environment and Society and Brown’s department of earth, environmental and planetary sciences, and the study’s lead author. “These are events that impact people’s lives and also agriculture in those regions. Understanding the dipole can help us better predict and better prepare for future climate change.”

The dipole the researchers studied formed from the interactions between the heat transport system of the Atlantic Ocean and an atmospheric loop, called a Walker Circulation, in the tropical Indian Ocean. The lower part of the atmospheric loop flows east to west across much of the region at low altitudes near the ocean surface, and the upper part flows west to east at higher altitudes. The higher air and lower air connect in one big loop.

Interruption and weakening of the Atlantic Ocean heat transport, which works like a conveyor belt made of ocean and wind currents, was brought on by massive melting of the Laurentide ice sheet that once covered most of Canada and the northern US. The melting cooled the Atlantic and consequent wind anomalies triggered the atmospheric loop over the tropical Indian Ocean to become more active and extreme. That then led to increased precipitation in the east side of the Indian Ocean (where Indonesia sits) and reduced precipitation in the west side, where East Africa sits.

Sea levels and melting

The researchers also show that during the period they studied, this effect was amplified by a lower sea level and the exposure of nearby continental shelves.

The scientists say more research is needed to figure out exactly what effect the exposed continental shelf and lower sea level has on the Indian Ocean’s east-west dipole, but they’re already planning to expand the work to investigate the question. While this line of the work on lower sea levels won’t play into modeling future conditions, the work they’ve done investigating how the melting of ancient glaciers impacts the Indian Ocean dipole and the heat transport system of the Atlantic Ocean may provide key insights into future changes as climate change brings about more melting.

“Greenland is currently melting so fast that it’s discharging a lot of freshwater into the North Atlantic Ocean in ways that are impacting the ocean circulation,” Russell says. “The work done here has provided a new understanding of how changes in the Atlantic Ocean circulation can impact Indian Ocean climate and through that rainfall in Africa and Indonesia.”

The study had funding from the Institute at Brown for Environment and Society and the National Science Foundation.

Source: Brown University

New images from NASA’s James Webb Space Telescope reveal for the first time galaxies with stellar bars at a time when the universe was a mere 25% of its present age.

“I took one look at these data, and I said, ‘We are dropping everything else!’”

Stellar bars are elongated features of stars stretching from the centers of galaxies into their outer disks.

The finding of so-called barred galaxies, similar to our Milky Way, this early in the universe will require astrophysicists to refine their theories of galaxy evolution.

Prior to the James Webb Space Telescope (JWST), images from the Hubble Space Telescope had never detected bars at such young epochs. In a Hubble image, one galaxy, EGS-23205, is little more than a disk-shaped smudge, but in the corresponding JWST image taken this past summer, it’s a beautiful spiral galaxy with a clear stellar bar.

“I took one look at these data, and I said, ‘We are dropping everything else!’” says Shardha Jogee, professor of astronomy at the University of Texas at Austin.

“The bars hardly visible in Hubble data just popped out in the JWST image, showing the tremendous power of JWST to see the underlying structure in galaxies,” she says, describing data from the Cosmic Evolution Early Release Science Survey (CEERS), led by UT Austin professor, Steven Finkelstein.

“It’s like going into a forest that nobody has ever gone into.”

The team identified another barred galaxy, EGS-24268, also from about 11 billion years ago, which makes two barred galaxies existing farther back in time than any previously discovered.

In an article accepted for publication in The Astrophysical Journal Letters, they highlight these two galaxies and show examples of four other barred galaxies from more than 8 billion years ago.

“For this study, we are looking at a new regime where no one had used this kind of data or done this kind of quantitative analysis before,” says Yuchen “Kay” Guo, a graduate student who led the analysis, “so everything is new. It’s like going into a forest that nobody has ever gone into.”

Bars play an important role in galaxy evolution by funneling gas into the central regions, boosting star formation.

“Bars solve the supply chain problem in galaxies,” Jogee says. “Just like we need to bring raw material from the harbor to inland factories that make new products, a bar powerfully transports gas into the central region where the gas is rapidly converted into new stars at a rate typically 10 to 100 times faster than in the rest of the galaxy.”

Bars also help to grow supermassive black holes in the centers of galaxies by channeling the gas part of the way.

The discovery of bars during such early epochs shakes up galaxy evolution scenarios in several ways.

“This discovery of early bars means galaxy evolution models now have a new pathway via bars to accelerate the production of new stars at early epochs,” Jogee says.

And the very existence of these early bars challenges theoretical models as they need to get the galaxy physics right in order to predict the correct abundance of bars. The team will be testing different models in their next papers.

JWST can unveil structures in distant galaxies better than Hubble for two reasons: First, its larger mirror gives it more light-gathering ability, allowing it to see farther and with higher resolution. Second, it can see through dust better as it observes at longer infrared wavelengths than Hubble.

Undergraduate students Eden Wise and Zilei Chen played a key role in the research by visually reviewing hundreds of galaxies, searching for those that appeared to have bars, which helped narrow the list to a few dozen for the other researchers to analyze with a more intensive mathematical approach.

Additional coauthors are from UT Austin and other institutions in the US, the UK, Japan, Spain, France, Italy, Australia, and Israel.

Funding for this research came from, in part, the Roland K. Blumberg Endowment in Astronomy, the Heising-Simons Foundation, and NASA. This work relied on resources at the Texas Advanced Computing Center.

Source: UT Austin