“People recovering from heart damage often face a long and tricky journey. Healing is challenging because of the constant movement tissues must withstand as the heart beats. The same is true for vocal cords. Until now there was no injectable material strong enough for the job,” says Guangyu Bao, a PhD candidate in the Department of Mechanical Engineering at McGill University.

The team, led by Professor Luc Mongeau and Assistant Professor Jianyu Li, developed a new injectable hydrogel for wound repair. The hydrogel is a type of biomaterial that provides room for cells to live and grow. Once injected into the body, the biomaterial forms a stable, porous structure allowing live cells to grow or pass through to repair the injured organs.

“The results are promising, and we hope that one day the new hydrogel will be used as an implant to restore the voice of people with damaged vocal cords, for example laryngeal cancer survivors,” says Guangyu Bao.

Putting it to the test

The scientists tested the durability of their hydrogel in a machine they developed to simulate the extreme biomechanics of human vocal cords. Vibrating at 120 times a second for over 6 million cycles, the new biomaterial remained intact while other standard hydrogels fractured into pieces, unable to deal with the stress of the load.

“We were incredibly excited to see it worked perfectly in our test. Before our work, no injectable hydrogels possessed both high porosity and toughness at the same time. To solve this issue, we introduced a pore-forming polymer to our formula,” says Guangyu Bao.

The innovation also opens new avenues for other applications like drug delivery, tissue engineering, and the creation of model tissues for drug screening, the scientists say. The team is even looking to use the hydrogel technology to create lungs to test COVID-19 drugs.

“Our work highlights the synergy of materials science, mechanical engineering and bioengineering in creating novel biomaterials with unprecedented performance. We are looking forward to translating them into the clinic,” said Professor Jianyu Li, who holds the Canada Research Chair in Biomaterials and Musculoskeletal Health.

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Arabia Terra is in the northern latitudes of Mars. Named in 1879 by Italian astronomer Giovanni Schiaparelli, this ancient land covers an area slightly larger than the European continent. Arabia Terra contains craters, volcanic calderas, canyons and beautiful bands of rock reminiscent of sedimentary rock layers in the Painted Desert or the Badlands.

These layers of rock and how they formed was the research focus for Koeppel along with his advisor, associate professor Christopher Edwards of NAU’s Department of Astronomy and Planetary Science along with Andrew Annex, Kevin Lewis and undergraduate student Gabriel Carrillo of Johns Hopkins University. Their study, titled “A fragile record of fleeting water on Mars,” was funded by the NASA Mars Data Analysis Program and recently published in the journal Geology.

“We were specifically interested in using rocks on the surface of Mars to get a better understanding of past environments three to four billion years ago and whether there could have been climatic conditions that were suitable for life on the surface,” Koeppel said. “We were interested in whether there was stable water, how long there could have been stable water, what the atmosphere might have been like and what the temperature on the surface might have been like.”

In order to get a better understanding of what happened to create the rock layers, the scientists focused on thermal inertia, which defines the ability of a material to change temperature. Sand, with small and loose particles, gains and loses heat quickly, while a solid boulder will remain warm long after dark. By looking at surface temperatures, they were able to determine the physical properties of rocks in their study area. They could tell if a material was loose and eroding away when it otherwise looked like it was solid.

“No one had done an in-depth thermal inertia investigation of these really interesting deposits that cover a large portion of the surface of Mars,” Edwards said.

To complete the study, Koeppel used remote sensing instruments on orbiting satellites. “Just like geologists on Earth, we look at rocks to try to tell stories about past environments,” Koeppel said. “On Mars, we’re a little bit more limited. We can’t just go to a rock outcrop and collect samples — we’re pretty reliant on satellite data. So, there are a handful of satellites orbiting Mars, and each satellite hosts a collection of instruments. Each instrument plays its own role in helping us describe the rocks that are on the surface.”

Through a series of investigations using this remotely gathered data, they looked at thermal inertia, plus evidence of erosion, the condition of the craters and what minerals were present.

“We figured out these deposits are much less cohesive than everyone previously thought they were, indicating that this setting could only have had water for only a brief period of time,” said Koeppel. “For some people, that kind of sucks the air out of the story because we often think that having more water for more time means there’s a greater chance of life having been there at one point. But for us, it’s actually really interesting because it brings up a whole set of new questions. What are the conditions that could have allowed there to be water there for a brief amount of time? Could there have been glaciers that melted quickly with outbursts of huge floods? Could there have been a groundwater system that percolated up out of the ground for only a brief period of time only to sink back down?”

Koeppel started his college career in engineering and physics but switched to studying the geological sciences while earning his master’s degree at The City College of New York. He came to NAU to work with Edwards and immerse himself in the thriving planetary science community of Flagstaff.

“I got into planetary science because of my excitement for exploring worlds beyond Earth. The universe is astoundingly big, even Mars is just the tip of the iceberg,” Koeppel said. “But we’ve been studying Mars for a few decades now, and at this point, we have a huge accumulation of data. We’re beginning to study it at levels that are comparable to ways we’ve been able to study Earth, and it’s a really exciting time for Mars science.”

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Voggel and her team were able to determine the masses of the two objects by looking at how the gravitational pull of the black holes influences the motion of the stars around them. The bigger black hole, located right at the core of NGC 7727, was found to have a mass almost 154 million times that of the Sun, while its companion is 6.3 million solar masses.

It is the first time the masses have been measured in this way for a supermassive black hole pair. This feat was made possible thanks to the close proximity of the system to Earth and the detailed observations the team obtained at the Paranal Observatory in Chile using the Multi-Unit Spectroscopic Explorer (MUSE) on ESO’s VLT, an instrument Voggel learnt to work with during her time as a student at ESO. Measuring the masses with MUSE, and using additional data from the NASA/ESA Hubble Space Telescope, allowed the team to confirm that the objects in NGC 7727 were indeed supermassive black holes.

Astronomers suspected that the galaxy hosted the two black holes, but they had not been able to confirm their presence until now since we do not see large amounts of high-energy radiation coming from their immediate surroundings, which would otherwise give them away. “Our finding implies that there might be many more of these relics of galaxy mergers out there and they may contain many hidden massive black holes that still wait to be found,” says Voggel. “It could increase the total number of supermassive black holes known in the local Universe by 30 percent.”

The search for similarly hidden supermassive black hole pairs is expected to make a great leap forward with ESO’s Extremely Large Telescope (ELT), set to start operating later this decade in Chile’s Atacama Desert. “This detection of a supermassive black hole pair is just the beginning,” says co-author Steffen Mieske, an astronomer at ESO in Chile and Head of ESO Paranal Science Operations. “With the HARMONI instrument on the ELT we will be able to make detections like this considerably further than currently possible. ESO’s ELT will be integral to understanding these objects.”

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The finding will help astronomers determine what BB is made of and provide insight into conditions during the formation of our solar system. The finding was published in The Planetary Science Journal on November 29, 2021.

“These observations are pushing the distances for active comets dramatically farther than we have previously known,” said Tony Farnham, a research scientist in the UMD Department of Astronomy and the lead author of the study.

Knowing when a comet becomes active is key to understanding what it’s made of. Often called “dirty snowballs” or “icy dirtballs,” comets are conglomerations of dust and ice left over from the formation of the solar system. As an orbiting comet approaches its closest point to the sun, it warms, and the ices begin to vaporize. How warm it must be to start vaporizing depends on what kind of ice it contains (e.g., water, carbon dioxide, carbon monoxide or some other frozen compound).

Scientists first discovered comet BB in June 2021 using data from the Dark Energy Survey, a collaborative, international effort to survey the sky over the Southern hemisphere. The survey captured the bright nucleus of the comet but did not have high-enough resolution to reveal the envelope of dust and vapor that forms when the comet becomes active.

At 100 km across, comet BB is the largest comet ever discovered by far, and it is farther from the sun than the planet Uranus. Most comets are around 1 km or so and much closer to the sun when they are discovered. When Farnham heard about the discovery, he immediately wondered if images of comet BB had been captured by the Transient Exoplanet Survey Satellite (TESS), which observes one area of the sky for 28 days at a time. He thought TESS’s longer exposure times could provide more detail.

Farnham and his colleagues combined thousands of images of comet BB collected by TESS from 2018 through 2020. By stacking the images, Farnham was able to increase the contrast and get a clearer view of the comet. But because comets move, he had to layer the images so that comet BB was precisely aligned in each frame. That technique removed the errant specks from individual shots while amplifying the image of the comet, which allowed researchers to see the hazy glow of dust surrounding BB, proof that BB had a coma and was active.

To ensure the coma wasn’t just a blur caused by the stacking of images, the team repeated this technique with images of inactive objects from the Kuiper belt, which is a region much farther from the sun than comet BB where icy debris from the early solar system is plentiful. When those objects appeared crisp, with no blur, researchers were confident that the faint glow around comet BB was in fact an active coma.

The size of comet BB and its distance from the sun suggests that the vaporizing ice forming the coma is dominated by carbon monoxide. Since carbon monoxide may begin to vaporize when it is up to five times farther away from the sun than comet BB was when it was discovered, it is likely that BB was active well before it was observed.

“We make the assumption that comet BB was probably active even further out, but we just didn’t see it before this,” Farnham said. “What we don’t know yet is if there’s some cutoff point where we can start to see these things in cold storage before they become active.”

According to Farnham, the ability to observe processes like the formation of a cometary coma farther than ever before opens an exciting new door for astronomers.

“This is just the beginning,” Farnham said. “TESS is observing things that haven’t been discovered yet, and this is kind of a test case of what we will be able to find. We have the potential of doing this a lot, once a comet is seen, going back through time in the images and finding them while they are at farther distances from the sun.”

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Using observations from NASA’s ICON mission, scientists presented the first direct measurements of Earth’s long-theorized dynamo on the edge of space: a wind-driven electrical generator that spans the globe 60-plus miles above our heads. The dynamo churns in the ionosphere, the electrically charged boundary between Earth and space. It’s powered by tidal winds in the upper atmosphere that are faster than most hurricanes and rise from the lower atmosphere, creating an electrical environment that can affect satellites and technology on Earth.

“Half of the motion of the plasma can be attributed to the winds that we observe right there on that same magnetic field line,” Immel said. “That tells you it’s an important observation to make if you want to predict what plasma is doing.”

ICON’s first year of observations coincided with solar minimum, the quiet phase of the Sun’s 11-year activity cycle. During this time, the Sun’s behavior was a low, constant hum. “We know the Sun’s not doing much, but we saw a lot of variability from below, and then remarkable changes in the ionosphere,” Immel said. That told the researchers they could rule out the Sun as the main influence.

As the Sun ramps up to its active phase, scientists will be able to study more complex changes and interactions between space and Earth’s atmosphere.

Immel said he is excited to have this confirmation of long-held ionosphere theories. “We found half of what causes the ionosphere to behave as it does right there in the data,” he said. “This is what we wanted to know.”

Still, Maute said, “This leaves room to explore what else is contributing to the ionosphere’s behavior.”

Tides ripple up through the sky, building in strength and growing before gusting through the ionosphere. The electric dynamo whirs in response.

The scientists analyzed the first year of ICON data, and found high-altitude winds strongly influence the ionosphere. “We traced the pattern of how the ionosphere moves, and there was a clear wave-like structure,” Harding said. Changes in the wind, he explained, directly corresponded to the dance of plasma 370 miles above Earth’s surface.

The farther the atmosphere stretches away from the surface, the thinner it becomes and the less turbulence there is to disrupt these motions. That means small tides generated near the surface can grow much larger when they reach the upper atmosphere. “Changes in the winds up there are mostly controlled by what happens below,” Harding said.

ICON’s new wind measurements help scientists understand these tidal patterns that span the globe and their effects.

In most generators, these components are bound tightly so they stay put and act predictably. But the ionosphere is free to move however it likes. “The current generates its own magnetic field, which fights Earth’s magnetic field as it’s passing through,” Immel said. “So you end up with a wire trying to get away from you. It’s a messy generator.”

Following the whims of the ionosphere is key to predicting space weather’s potential impacts. Depending on which way the wind blows, plasma in the ionosphere shoots out into space or plummets toward Earth. This behavior results from the tug-of-war between the ionosphere and Earth’s electromagnetic fields.

The dynamo, which lies at the lower end of the ionosphere, has remained a mystery for so long because it’s difficult to observe. Too high for scientific balloons and too low for satellites, it has eluded many of the tools researchers have to study near-Earth space. ICON is uniquely equipped to investigate this part of the ionosphere from above by taking advantage of the upper atmosphere’s natural glow to detect the motion of plasma.

ICON simultaneously observes powerful winds and migrating plasma. “This was the first time we could tell how much the wind contributes to the ionosphere’s behavior, without any assumptions,” said Astrid Maute, another study co-author and ICON scientist at the National Center for Atmospheric Research in Boulder, Colorado.

Only in the past decade or so, Immel said, have scientists realized just how much those rising winds vary. “The upper atmosphere wasn’t expected to change rapidly,” he said. “But it does, day to day. We’re finding this is all due to changes driven up from the lower atmosphere.”

Wind power

Familiar are the winds that skim the surface of Earth, from gentle breezes to bracing gusts that blow one way and then the other.

High-altitude winds are a different beast. From 60 to 95 miles above the ground, in the lower thermosphere, winds can blast in the same direction at the same speed — around 250 mph — for a few hours at a time before suddenly reversing direction. (By comparison, winds in the strongest Category 5 hurricanes tear at 157 mph or more.)

These dramatic shifts are the result of waves of air, called tides, born at Earth’s surface when the lower atmosphere heats up during the day then cools down at night. They surge through the sky daily, carrying changes from below.

The new work, published today in Nature Geoscience, improves our understanding of the ionosphere, which helps scientists better predict space weather and protect our technology from its effects.

Launched in 2019, ICON, short for Ionospheric Connection Explorer, is a mission to untangle how Earth’s weather interacts with the weather in space. Radio and GPS signals zip through the ionosphere, which is home to auroras and the International Space Station. Empty pockets or dense swells of electrically charged particles can disrupt these signals.

Scientists who study the atmosphere and space weather have long included Earth’s dynamo in their models because they knew it had important effects. But with little information, they had to make some assumptions about how it works. Data from ICON is the first concrete observation of winds fueling the dynamo, eventually influencing space weather, to feed into those models.

“ICON’s first year in space has shown predicting these winds is key to improving our ability to predict what happens in the ionosphere,” said Thomas Immel, ICON principal investigator at University of California, Berkeley, and lead author of the new study.

Earth’s sky-high generator

The ionosphere is like a sloshing sea of electrically charged particles, created by the Sun and intermixed with the neutral upper atmosphere. Sandwiched between Earth and space, the ionosphere responds to changes from both the Sun above and Earth below. How much influence comes from each side is what researchers are interested in figuring out. Studying a year of ICON data, the researchers found much of the change they observed originated in the lower atmosphere.

Generators work by repeatedly moving an electricity-carrying conductor — like a copper wire — through a magnetic field. Filled with electrically charged gases called plasma, the ionosphere acts like a wire, or rather, a tangled mess of wires: Electricity flows right through. Like the dynamo in Earth’s core, the dynamo in the atmosphere produces electromagnetic fields from motion.

Strong winds in the thermosphere, a layer of the upper atmosphere known for its high temperatures, push current-carrying plasma in the ionosphere across invisible magnetic field lines that arc around Earth like an onion. The wind tends to push on chunky, positively charged particles more than small, negatively charged electrons. “You get pluses moving differently than minuses,” said co-author Brian Harding, a physicist at University of California, Berkeley. “That’s an electric current.”

Video about strong winds that power electrical field in Earth’s upper atmosphere: https://www.youtube.com/watch?v=pt9RCMZmMkc