ST/ Second-most distant galaxy discovered using James Webb Space Telescope

Paradigm

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Paradigm

35 min readNov 23, 2023

Space biweekly vol.88, 7th November — 23rd November

TL;DR

The second- and fourth-most distant galaxies ever observed have been discovered in a region of space known as Pandora’s Cluster, or Abell 2744, using data from NASA’s James Webb Space Telescope.
Scientists just made a breakthrough discovery in revealing how planets are made. By observing water vapor in protoplanetary disks, they confirmed a physical process involving the drifting of ice-coated solids from the outer regions of the disk into the rocky-planet zone.
Almost every large galaxy has a supermassive black hole at its center. An international research team has recently observed the Circinus galaxy, which is one of the closest galaxies to the Milky Way, with high enough resolution to gain further insights into the gas flows to and from the black hole at its galactic nucleus.
Astronomers have discovered the most distant barred spiral galaxy, similar to the Milky Way, that has been observed to date.
Giant gas planets can be agents of chaos, ensuring nothing lives on their Earth-like neighbors around other stars. New studies show, in some planetary systems, the giants tend to kick smaller planets out of orbit and wreak havoc on their climates
Scientists have observed, for the first time in the visible range, a glow on the night side of the planet Mars. These new observations provide a better understanding of the dynamics of the upper atmosphere of the Red Planet and its variations throughout the year.
Earth and space scientists document and reveal the mechanisms behind strike-slip faulting on the largest moon of Saturn, Titan, and Jupiter’s largest moon, Ganymede.
Scientists have discovered 14 new transient objects during their time-lapse study of galaxy cluster MACS0416 — located about 4.3 billion light years from Earth — which they’ve dubbed as the ‘Christmas Tree Galaxy Cluster.’
Research into how 3D printing works in a weightless environment aims to support long-term exploration and habitation on spaceships, the moon or Mars.
Large geomagnetic storms disrupt radio signals and GPS. Now, researchers have identified the previous underestimated role of the ionosphere, a region of Earth’s upper atmosphere that contains a high concentration of ions and free electrons, in determining how such storms develop. Understanding the interactions that cause large geomagnetic storms is important because they can disrupt radio signals and GPS. Their findings may help predict storms with the greatest potential consequences.
And more!

Space industry in numbers

The global smart space market size is projected to grow from USD 9.4 billion in 2020 to USD 15.3 billion by 2025, at a Compound Annual Growth Rate (CAGR) of 10.2% during the forecast period. The increasing venture capital funding and growing investments in smart space technology to drive market growth.

Analysts at Morgan Stanley and Goldman Sachs have predicted that economic activity in space will become a multi-trillion-dollar market in the coming decades. Morgan Stanley’s Space Team estimates that the roughly USD 350 billion global space industry could surge to over USD 1 trillion by 2040.

Source: Satellite Industry Association, Morgan Stanley Research, Thomson Reuters. *2040 estimates

Space industry news

Latest research

UNCOVER: Illuminating the Early Universe — JWST/NIRSpec Confirmation of z > 12 Galaxies

by Bingjie 冰洁 Wang 王, Seiji Fujimoto, Ivo Labbé, Lukas J. Furtak, et al in The Astrophysical Journal Letters

The second- and fourth-most distant galaxies ever observed have been discovered in a region of space known as Pandora’s Cluster, or Abell 2744, using data from NASA’s James Webb Space Telescope (JWST). Following up on a deep field image of the area, an international team led by Penn State researchers confirmed the distance of these ancient galaxies and inferred their properties using new spectroscopic data — information about light emitted across the electromagnetic spectrum — from JWST. At nearly 33 billion light years away, these incredibly distant galaxies offer insights into how the earliest galaxies might have formed.

Unlike other galaxies confirmed at this distance that appear in images as red dots, the new galaxies are larger and appear like a peanut and a fluffy ball, according to the researchers.

“Very little is known about the early universe, and the only way to learn about that time and to test our theories of early galaxy formation and growth is with these very distant galaxies,” said first-author Bingjie Wang, postdoctoral scholar in the Penn State Eberly College of Science and a member of the JWST UNCOVER (Ultradeep NIRSpec and NIRCam ObserVations before the Epoch of Reionization) team that conducted the research. “Prior to our analysis, we knew of only three galaxies confirmed at around this extreme distance. Studying these new galaxies and their properties has revealed the diversity of galaxies in the early universe and how much there is to be learned from them.”

Because the light from these galaxies had to travel for so long to reach Earth, it provides a window into the past. The research team estimates that the light detected by JWST was emitted by the two galaxies when the universe was about 330 million years old and traveled for about 13.4 billion light years to reach the JWST. But, the researchers said, the galaxies are currently closer to 33 billion light years away from Earth due to the expansion of the universe over this time.

“The light from these galaxies is ancient, about three times older than the Earth,” said Joel Leja, assistant professor of astronomy and astrophysics at Penn State and a member of UNCOVER. “These early galaxies are like beacons, with light bursting through the very thin hydrogen gas that made up the early universe. It is only by their light that we can begin to understand the exotic physics that governed the galaxy near the cosmic dawn.”

Notably, the two galaxies are considerably larger than the three galaxies previously located at these extreme distances. One is at least six times larger at about 2,000 light years across. For comparison, the Milky Way is approximately 100,000 light years across, but, Wang said, the early universe is thought to have been very compressed, so it’s surprising that the galaxy is as large as it is.

“Previously discovered galaxies at these distances are point sources — they appear as a dot in our images,” Wang said. “But one of ours appears elongated, almost like a peanut, and the other looks like a fluffy ball. It is unclear if the difference in size is due to how the stars formed or what happened to them after they formed, but the diversity in the galaxy properties is really interesting. These early galaxies are expected to have formed out of similar materials, but already they are showing signs of being very different than one another.”

The two galaxies were among 60,000 sources of light in Pandora’s Cluster detected in one of JWST’s first deep field images taken during 2022, its first year of science operations. This region of space was selected in part because it is located behind several galaxy clusters that create a natural magnification effect called gravitational lensing. The gravitational pull of the clusters’ combined mass warps the space around it, focusing and magnifying any light that passes nearby and providing a magnified view behind the clusters.

In a matter of months, the UNCOVER team narrowed down the 60,000 light sources to 700 candidates for follow up study, eight of which they thought could potentially be among the first galaxies. Then, JWST again pointed at Pandora’s Cluster, recording the candidates’ spectra — a sort of fingerprint detailing the amount of light given off at each wavelength.

“Several different teams are using different approaches to look for these ancient galaxies, and each have their strengths and weaknesses,” Leja said. “The fact that we’re pointing at this giant magnifying lens in space gives us an incredibly deep window, but it’s a very small window so we were rolling the dice. Several of the candidates were inconclusive, and at least one was a case of mistaken identity — it was something much closer that mimics a distant galaxy. But we were lucky, and two turned out to be these ancient galaxies. It’s incredible.”

The researchers also used detailed models to infer the properties of these early galaxies when they emitted the light detected by JWST. As the researchers expected, the two galaxies were young, had few metals in their composition, and were growing rapidly and actively forming stars.

“The first elements were forged in the cores of early stars through the process of fusion,” Leja said. “It makes sense that these early galaxies don’t have heavy elements like metals because they were some of the first factories to build those heavy elements. And, of course, they would have to be young and star-forming to be the first galaxies, but confirming these properties is an important basic test of our models and helps confirm the whole paradigm of the Big Bang theory.”

The researchers noted that, alongside the gravitational lens, JWST’s powerful infrared instruments should be able to detect galaxies at an even further distance, if they exist.

“We had a very tiny window into this region, and we didn’t observe anything beyond these two galaxies, even though JWST has the capability,” Leja said. “That could mean that galaxies just didn’t form before that time and that we’re not going to find anything further away. Or it could mean we didn’t get lucky enough with our small window.”

This work was the result of a successful proposal submitted to NASA suggesting how to use JWST during its first year of science operations. In the first three cycles of submissions, NASA received four to ten times more proposals than available observing time on the telescope would allow and had to select only a fraction of those proposals.

“Our team was very excited and a little surprised when our proposal was accepted,” Leja said. “It involved coordination, quick human action and the telescope pointing at the same thing twice, which is a lot to ask of a telescope in its first year. There was a lot of pressure because we only had a few months to determine the objects for follow up. But JWST was built for finding these first galaxies, and it’s so exciting to be doing that now.”

JWST Reveals Excess Cool Water near the Snow Line in Compact Disks, Consistent with Pebble Drift

by Andrea Banzatti, Klaus M. Pontoppidan, et al in The Astrophysical Journal Letters

Scientists using NASA’s James Webb Space Telescope just made a breakthrough discovery in revealing how planets are made. By observing water vapor in protoplanetary disks, Webb confirmed a physical process involving the drifting of ice-coated solids from the outer regions of the disk into the rocky-planet zone.

Theories have long proposed that icy pebbles forming in the cold, outer regions of protoplanetary disks — the same area where comets originate in our solar system — should be the fundamental seeds of planet formation. The main requirement of these theories is that pebbles should drift inward toward the star due to friction in the gaseous disk, delivering both solids and water to planets.

A fundamental prediction of this theory is that as icy pebbles enter into the warmer region within the “snowline” — where ice transitions to vapor — they should release large amounts of cold water vapor. This is exactly what Webb observed.

The distribution of upper level energies Eu and Einstein-A coefficients (top panels, with color-coding reflecting Eu values) across infrared wavelengths naturally traces radial temperature gradients in inner disks within and across the water snow line (bottom panel, where the spectrum is scaled to a distance of 130 pc).

“Webb finally revealed the connection between water vapor in the inner disk and the drift of icy pebbles from the outer disk,” said principal investigator Andrea Banzatti of Texas State University, San Marcos, Texas. “This finding opens up exciting prospects for studying rocky planet formation with Webb!”
“In the past, we had this very static picture of planet formation, almost like there were these isolated zones that planets formed out of,” explained team member Colette Salyk of Vassar College in Poughkeepsie, New York. “Now we actually have evidence that these zones can interact with each other. It’s also something that is proposed to have happened in our solar system.”

The researchers used Webb’s MIRI (the Mid-Infrared Instrument) to study four disks — two compact and two extended — around Sun-like stars. All four of these stars are estimated to be between 2 and 3 million years old, just newborns in cosmic time. The two compact disks are expected to experience efficient pebble drift, delivering pebbles to well within a distance equivalent to Neptune’s orbit. In contrast, the extended disks are expected to have their pebbles retained in multiple rings as far out as six times the orbit of Neptune.

The Webb observations were designed to determine whether compact disks have a higher water abundance in their inner, rocky planet region, as expected if pebble drift is more efficient and is delivering lots of solid mass and water to inner planets. The team chose to use MIRI’s MRS (the Medium-Resolution Spectrometer) because it is sensitive to water vapor in disks.

The results confirmed expectations by revealing excess cool water in the compact disks, compared with the large disks. As the pebbles drift, any time they encounter a pressure bump — an increase in pressure — they tend to collect there. These pressure traps don’t necessarily shut down pebble drift, but they do impede it. This is what appears to be happening in the large disks with rings and gaps. Current research proposes that large planets may cause rings of increased pressure, where pebbles tend to collect. This also could have been a role of Jupiter in our solar system — inhibiting pebbles and water delivery to our small, inner, and relatively water-poor rocky planets.

When the data first came in, the results were puzzling to the research team. “For two months, we were stuck on these preliminary results that were telling us that the compact disks had colder water, and the large disks had hotter water overall,” remembered Banzatti. “This made no sense, because we had selected a sample of stars with very similar temperatures.”

Only when Banzatti overlaid the data from the compact disks onto the data from the large disks did the answer clearly emerge: the compact disks have extra cool water just inside the snowline, at about ten times closer than the orbit of Neptune.

“Now we finally see unambiguously that it is the colder water that has an excess,” said Banzatti. “This is unprecedented and entirely due to Webb’s higher resolving power!”

Supermassive black hole feeding and feedback observed on subparsec scales

by Takuma Izumi, Keiichi Wada, Masatoshi Imanishi, Kouichiro Nakanishi, et al in Science

An international research team led by Takuma Izumi, an assistant professor at the National Astronomical Observatory of Japan, has observed in high resolution (approximately 1 light year) the active galactic nucleus of the Circinus Galaxy — one of the closest major galaxies to the Milky Way. The observation was made possible by the Atacama Large Millimeter/Submillimeter Array (ALMA) astronomical observatory in Chile.

This breakthrough marks the world’s first quantitative measurement at this scale of gas flows and their structures of a nearby supermassive black hole in all phase gases, including plasma, atomic, and molecular. Such high resolution allowed the team to team to capture the accretion flow heading towards the supermassive black hole, revealing that this accretion flow is generated by a physical mechanism known as ‘gravitational instability.’ Furthermore, the team also found that a significant portion of this accretion flow does not contribute to the growth of the black hole. Instead, most of the gas is expelled from the vicinity of the black hole as atomic or molecular outflows, and returns to the gas disk to participate again into an accretion flow towards the black hole, much like how water gets recycled in a water fountain. These findings represent a crucial advancement towards a greater understanding of the growth mechanisms of supermassive black holes.

‘Supermassive black holes,’ with masses exceeding a million times that of the Sun, exist at the centers of many galaxies. But astronomers have long pondered the mechanisms responsible their formation. One proposed mechanism, as outlined in previous research, suggests that gas accretes onto the black hole as it gravitates towards the center of the host galaxy.

The central region of the Circinus Galaxy observed with ALMA.

As gas approaches the supermassive black holes, the intense gravitational pull of the black hole causes the gas to accelerate. The resulting increase in friction between gas particles leads to the gas heating up to temperatures as high as several million degrees and results in the emission of brilliant light. Known as an active galactic nucleus (AGN), the brightness can at times surpass the combined light of all the stars in the galaxy. Interestingly, a portion of the gas that falls towards the black hole (accretion flow) is thought to be blown away by the immense energy of this active galactic nucleus, leading to outflows.

Previous theoretical and observational studies have provided detailed insights into gas accretion mechanisms from the 100,000 light-years scale down to a scale of a few hundred light-years at the center. However, gas accretion occurs a few dozen light-years from the galactic center. This limited spacial scale has hindered further understanding of the accretion process. For instance, to comprehend quantitatively the growth of black holes, it is necessary to measure the accretion flow rate (how much gas is flowing in) and to determine the amounts and types of gases (plasma, atomic gas, molecular gas) that are expelled as outflows at that small scale. Unfortunately, observational understanding has not progressed significantly until now.

“Observations of multiphase gases can provide a more comprehensive and thorough understanding of the distribution and dynamics of matter around a black hole and our observation marks the highest resolution ever achieved for multiphase gas observations in an active galactic nucleus,” points out Izumi.

Izumi and his colleagues initially captured, for the first time, the accretion flow heading towards the supermassive black hole within the high-density gas disk that extends over several light-years from the galactic center. Identifying this accretion flow had long been a challenge due to the small scale of the region and the complex motions of gas near the galactic center. However, the research team pinpointed the location where the foreground molecular gas was absorbing the light from the active galactic nucleus shining brightly in the background. Detailed analysis revealed that this absorbing material is moving away from Earth. As the absorbing material consistently resides between the active galactic nucleus and Earth, this indicates that the team has successfully captured the accretion flow heading toward the active galactic nucleus.

The study also elucidated the physical mechanism responsible for inducing this gas accretion. The observed gas disk exhibited a gravitational force so substantial that it could not be sustained by the pressure calculated from the gas disk’s motion. When this situation occurs, the gas disk collapses under its own weight, forming complex structures and losing its ability to maintain stable motion at the galactic center. Consequently, the gas rapidly falls towards the central black hole, A phenomenon known as “gravitational instability” at the heart of the galaxy.

Furthermore, the study advanced quantitative understanding of gas flows around the active galactic nucleus. By considering the density of the observed gas and the velocity of the accretion flow, the researchers were able to calculate the rate at which gas is supplied to the black hole. Surprisingly, this rate was found to be 30 times greater than what is needed to sustain the active galactic nucleus. In other words, the majority of the accretion flow at the 1-light-year scale around the galactic center was not contributing to the growth of the black hole.

So, where did this surplus gas go? High-sensitivity observations of all phase gases with ALMA detected outflows from the active galactic nucleus. Quantitative analysis revealed that the majority of the gas flowing towards the black hole was expelled as atomic or molecular outflows. However, due to their slow velocities, they couldn’t escape the gravitational pull of the black hole and eventually returned to the gas disk. There, they were recycled into an accretion flow toward the black hole, completing a fascinating gas recycling process at the galactic center.

Reflecting on the achievements Takuma Izumi iterates, “Detecting accretion flows and outflows in a region just a few light-years around the actively growing supermassive black hole, particularly in a multiphase gas, and even deciphering the accretion mechanism itself, are monumental achievements in the quest to reveal more about supermassive black holes.” Looking ahead to the future, he continues, “To gain a comprehensive understanding of the growth of supermassive black holes in cosmic history, it is essential to investigate various types of supermassive black holes that are located farther away from us. This requires high-resolution and high-sensitivity observations, and we have high expectations for the continued use of ALMA, as well as for upcoming large radio interferometers in the next generation.”

A Milky Way-like barred spiral galaxy at a redshift of 3

by Luca Costantin, Pablo G. Pérez-González, et al in Nature

Using the James Webb Space Telescope, an international team, including astronomer Alexander de la Vega of the University of California, Riverside, has discovered the most distant barred spiral galaxy similar to the Milky Way that has been observed to date.

Until now it was believed that barred spiral galaxies like the Milky Way could not be observed before the universe, estimated to be 13.8 billion years old, reached half of its current age.

“This galaxy, named ceers-2112, formed soon after the Big Bang,” said coauthor de la Vega, a postdoctoral researcher in the Department of Physics and Astronomy. “Finding ceers-2112 shows that galaxies in the early universe could be as ordered as the Milky Way. This is surprising because galaxies were much more chaotic in the early universe and very few had similar structures to the Milky Way.”

Ceers-2112 has a bar in its center. De la Vega explained that a galactic bar is a structure, made of stars, within galaxies. Galactic bars resemble bars in our everyday lives, such as a candy bar. It is possible to find bars in non-spiral galaxies, he said, but they are very rare.

“Nearly all bars are found in spiral galaxies,” said de la Vega, who joined UCR last year after receiving his doctoral degree in astronomy at Johns Hopkins University. “The bar in ceers-2112 suggests that galaxies matured and became ordered much faster than we previously thought, which means some aspects of our theories of galaxy formation and evolution need revision.”

Astronomers’ previous understanding of galaxy evolution was that it took several billion years for galaxies to become ordered enough to develop bars.

“The discovery of ceers-2112 shows that it can happen in only a fraction of that time, in about one billion years or less,” de la Vega said.

According to him, galactic bars are thought to form in spiral galaxies with stars that rotate in an ordered fashion, the way they do in the Milky Way.

“In such galaxies, bars can form spontaneously due to instabilities in the spiral structure or gravitational effects from a neighboring galaxy,” de la Vega said. “In the past, when the universe was very young, galaxies were unstable and chaotic. It was thought that bars could not form or last long in galaxies in the early universe.”

Stellar population properties of ceers-2112.

The discovery of ceers-2112 is expected to change at least two aspects of astronomy.

“First, theoretical models of galaxy formation and evolution will need to account for some galaxies becoming stable enough to host bars very early in the universe’s history,” de la Vega said. “These models may need to adjust how much dark matter makes up galaxies in the early universe, as dark matter is believed to affect the rate at which bars form. Second, the discovery of ceers-2112 demonstrates that structures like bars can be detected when the universe was very young. This is important because galaxies in the distant past were smaller than they are now, which makes finding bars harder. The discovery of ceers-2112 paves the way for more bars to be discovered in the young universe.”

De la Vega helped the research team by estimating the redshift and properties of ceers-2112. He also contributed to the interpretation of the measurements.

“Redshift is an observable property of a galaxy that indicates how far away it is and how far back in time the galaxy is seen, which is a consequence of the finite speed of light,” he said.

What surprised de la Vega most about the discovery of ceers-2112 is how well the properties of its bar could be constrained.

“Initially, I thought detecting and estimating properties of bars in galaxies like ceers-2112 would be fraught with measurement uncertainties,” he said. “But the power of the James Webb Space Telescope and the expertise of our research team helped us place strong constraints on the size and shape of the bar.”

At UCR, de la Vega oversees astronomy outreach. He plans telescope nights on and off campus, and visits to local schools to give presentations on astronomy. He also leads the public astronomy talk series “Cosmic Thursdays” as well as one-off events for special occasions, such as viewing parties for eclipses.

Surrounded by Giants: Habitable Zone Stability Within the HD 141399 System

by Stephen R. Kane in The Astronomical Journal

Giant gas planets can be agents of chaos, ensuring nothing lives on their Earth-like neighbors around other stars. New studies show, in some planetary systems, the giants tend to kick smaller planets out of orbit and wreak havoc on their climates.

Jupiter, by far the biggest planet in our solar system, plays an important protective role. Its enormous gravitational field deflects comets and asteroids that might otherwise hit Earth, helping create a stable environment for life. However, giant planets elsewhere in the universe do not necessarily protect life on their smaller, rocky planet neighbors.

A new paper details how the pull of massive planets in a nearby star system are likely to toss their Earth-like neighbors out of the “habitable zone.” This zone is defined as the range of distances from a star that are warm enough for liquid water to exist on a planet’s surface, making life possible. Unlike most other known solar systems, the four giant planets in HD 141399 are farther from their star. This makes it a good model for comparison with our solar system where Jupiter and Saturn are also relatively far from the sun.

“It’s as if they have four Jupiters acting like wrecking balls, throwing everything out of whack,” said Stephen Kane, UC Riverside astrophysicist and author of the journal paper.

HZ and planetary orbits in the HD 141399 system, where the orbits are labeled by planet designation. The extent of the HZ is shown in green, where light green and dark green indicate the CHZ and OHZ, respectively. The scale of the figure is 9.63 au along each side.

Taking data about the system’s planets into account, Kane ran multiple computer simulations to understand the effect of these four giants. He wanted specifically to look at the habitable zone in this star system and see if an Earth could remain in a stable orbit there.

“The answer is yes, but it’s very unlikely. There are only a select few areas where the giants’ gravitational pull would not knock a rocky planet out of its orbit and send it flying right out of the zone,” Kane said.

While this paper shows giant planets outside the habitable zone destroying the chances for life, a second, related paper shows how one big planet in the middle of the zone would have a similar effect.

This second paper examines a star system only 30 light years away from Earth called GJ 357. For reference, the galaxy is estimated to be 100,000 light years in diameter, so this system is “definitely in our neighborhood,” Kane said.

Earlier studies found that a planet in this system, named GJ 357 d, resides in the system’s habitable zone and has been measured at about six times the mass of the Earth. However, in this paper, Kane shows the mass is likely much bigger.

“It’s possible GJ 357 d is as much as 10 Earth masses, which means it’s probably not terrestrial, so you couldn’t have life on it,” Kane said. “Or at least, it would not be able to host life as we know it.”

In the second part of the paper, Kane and his collaborator, UCR planetary science postdoctoral scholar Tara Fetherolf, demonstrate that if the planet is much larger than previously believed, it is certain to prevent more Earth-like planets from residing in the habitable zone alongside it. Though there are also a select few locations in the habitable zone of this system where an Earth could potentially reside, their orbits would be highly elliptical around the star.

“In other words, the orbits would produce crazy climates on those planets,” Kane said. “This paper is really a warning, when we find planets in the habitable zone, not to assume they are automatically capable of hosting life.”

Observation of the Mars O2 visible nightglow by the NOMAD spectrometer onboard the Trace Gas Orbiter

by J.-C. Gérard, L. Soret, I. R. Thomas, B. Ristic, Y. Willame, C. Depiesse, A. C. Vandaele, F. Daerden, B. Hubert, J. P. Mason, M. R. Patel, M. A. López-Valverde in Nature Astronomy

An international team led by scientists from the University of Liège has observed, for the first time in the visible range, a glow on the night side of the planet Mars. These new observations provide a better understanding of the dynamics of the upper atmosphere of the Red Planet and its variations throughout the year.

A scientific team led by researchers from the Laboratory for Planetary and Atmospheric Physics (LPAP) at the University of Liège (BE) has just observed, for the first time, lights in the night sky over Mars using the UVIS-NOMAD instrument on board the Trace Gas Orbiter (TGO) satellite of the European Space Agency (ESA). This instrument is part of the NOMAD spectrometer suite developed at the Royal Institute for Space Aeronomy in Uccle, and tested and calibrated at the Liège Space Centre. It was inserted into circular Martian orbit at an altitude of 400 km in 2008.

Initially designed to map the ozone layer surrounding the planet in the ultraviolet, UVIS-NOMAD covers a spectral range extending from the near ultraviolet to red. For this purpose, the instrument is usually oriented towards the centre of the planet and observes sunlight reflected by the planetary surface and atmosphere. Based on a proposal from our laboratory, the instrument was oriented towards the limb of the planet in order to observe its atmosphere from the edge,” explains Jean-Claude Gérard, planetologist at ULiège. Back in 2020, we were already able to detect the presence of a green emission between 40 and 150 km in altitude, present during the Martian day. This was due to the dissociation of the CO2 molecule, the main constituent of the atmosphere, by ultraviolet solar radiation.”

The TGO satellite, when observing the atmosphere at night, has just detected a new emission between 40 and 70 km altitude. This emission is due to the recombination of oxygen atoms created in the summer atmosphere and carried by the winds towards the high winter latitudes, explains Lauriane Soret, a researcher at LPAP. There, the atoms recombine on contact with CO2 to reform an O2 molecule in an excited state that relaxes and emits light in the visible range. This light emission is concentrated in the polar regions to the north and south, where the oxygen atoms converge in the downward branch of the gigantic trajectory from the opposite hemisphere. The intensity of the emission is high, in the visible range. This process seems to be reversed every half Martian year, and the luminosity then changes hemisphere. A similar emission was analysed on Venus by the same team using images from the Venus Express satellite. On Venus, the atoms travel from the sunlit side to the dark side where they emit the same glow as on Mars.

LPAP researchers played a key role in these observations. After highlighting the presence of a layer of green light surrounding the planet on the day side, they identified the night-time emission. The study will be continued during the TGO mission and will provide us with valuable information about the dynamics of the Martian upper atmosphere and its variations over the course of the Martian year,” continues Lauriane Soret. We have noticed that another ultraviolet emission due to the nitric oxide (NO) molecule is also observed by UVIS in the same regions. Comparing the two emissions will enable us to refine the diagnosis and identify the processes involved.

The NO molecule also emits light when oxygen and nitrogen atoms recombine. As with the radiation from the O2 molecule, the atoms are formed in sunlight, transported by the winds to the other hemisphere and recombine during the downward motion in the polar regions.

These new observations are unexpected and interesting for future journeys to the Red Planet,” enthuses Jean-Claude Gérard. The intensity of the night glow in the polar regions is such that simple and relatively inexpensive instruments in Martian orbit could map and monitor atmospheric flows. A future ESA mission could carry a camera for global imaging. In addition, the emission is sufficiently intense to be observable during the polar night by future astronauts in orbit or from the Martian ground’.
Benoit Hubert, researcher at LPAP, concludes: “Remote sensing of these emissions is an excellent tool for probing the composition and dynamics of Mars’ upper atmosphere between 40 and 80 km. This region is inaccessible to direct methods of measuring composition using satellites’’.

Exploring the initial landing site area of Dragonfly on Titan: Insights into shear failure and strike-slip faulting at Selk crater

by Liliane M.L. Burkhard, Sarah A. Fagents in Icarus

On the surface of many of the icy moons in our solar system, scientists have documented strike-slip faults, those that occur when fault walls move past one another sideways, as is the case at the San Andreas fault in California. Two recently published studies led by University of Hawai’i at Manoa earth and space scientists document and reveal the mechanisms behind these geologic features on the largest moon of Saturn, Titan, and Jupiter’s largest moon, Ganymede.

“We are interested in studying shear deformation on icy moons because that type of faulting can facilitate the exchange of surface and subsurface materials through shear heating processes, potentially creating environments conducive for the emergence of life,” said Liliane Burkhard, lead author of the studies and research affiliate at the Hawai’i Institute of Geophysics and Planetology in the UH Manoa School of Ocean and Earth Science and Technology.

When an icy moon moves around its parent planet, the gravity of the planet can cause tidal flexing of the surface of the moon, which can drive geologic activity such as strike-slip faulting. Tidal stresses vary as the moon changes distance from its planet because the moon’s orbit can be elliptical rather than circular.

The extremely cold temperatures on the surface of Titan mean that water ice acts as rock that can crack, fault, and deform. Evidence from the Cassini spacecraft suggests that tens of miles below the frozen surface, there is a liquid water ocean. Further, Titan is the only moon in our solar system with a dense atmosphere, which, uniquely, supports an Earth-like hydrological cycle of methane clouds, rain, and liquid flowing across the surface to fill lakes and seas, placing it among a handful of worlds that could potentially contain habitable environments.

The NASA Dragonfly mission will launch in 2027, with a planned arrival on Titan in 2034. The novel rotorcraft lander will conduct several flights on the surface, exploring a variety of locations to search for the building blocks and signs of life. In their investigation of the Selk crater area on Titan, the designated initial landing site for the Dragonfly mission, Burkhard and her co-author explored the potential for shear deformations and strike-slip faulting. To do this, they calculated the stress that would be exerted on Titan’s surface due to tidal forces as the moon orbits Saturn and tested the possibility of faulting by examining various characteristics of the frozen ground.

“While our prior research indicated that certain areas on Titan might currently undergo deformation due to tidal stresses, the Selk crater area would need to host very high pore fluid pressures and a low crustal coefficient of friction for shear failure, which seems improbable,” said Burkhard. “Consequently, it’s safe to infer that Dragonfly won’t be landing in a strike-slip ditch!”

In a second publication, Burkhard and her co-authors investigated the geologic history of Ganymede, Jupiter’s largest moon, in the area of Nippur/Philus Sulci by examining high-resolution data available for this region and conducting a tidal stress investigation of Ganymede’s past.

Ganymede has documented strike-slip faults on the surface, but its current orbit is too circular, as opposed to elliptical, to cause any tidal stress deformation. The researchers found that several crosscutting bands of light terrain in the Nippur/Philus Sulci site show varying degrees of tectonic deformation, and the chronology of tectonic activity implied by mapped crosscutting relationships revealed three eras of distinct geologic activity: ancient, intermediate and youngest.

“I investigated strike-slip faulting features in intermediate-aged terrain, and they correspond in slip direction to the predictions from modeling stresses of a higher past eccentricity. Ganymede could have undergone a period where its orbit was much more elliptical than it is today,” said Burkhard.

Other shear features found in younger geologic units in the same region do not align in slip direction with typical first-order shear indicators.

“This suggests that these features might have formed through another process and not necessarily due to higher tidal stresses,” Burkhard added. “So, Ganymede has had a tidal ‘mid-life crisis’, but its youngest ‘crisis’ remains enigmatic.”

The recent studies along with space exploration missions create a positive feedback of knowledge.

“Geologic investigations, such as these, prior to launch and arrival, inform and guide mission activities,” said Burkhard. “And missions such as Dragonfly, Europa Clipper and ESA’s JUICE will further constrain our modeling approach and can help pinpoint the most interesting locations for lander exploration and possibly for gaining access to the interior ocean of icy moons.”

JWST’s PEARLS: Transients in the MACS J0416.1–2403 Field

by Haojing Yan, Zhiyuan Ma, Bangzheng Sun, et al in The Astrophysical Journal

An international team of scientists, led by University of Missouri’s Haojing Yan, used NASA’s James Webb Space Telescope (JWST) to discover 14 new transient objects during their time-lapse study of galaxy cluster MACS0416 — located about 4.3 billion light years from Earth — which they’ve dubbed as the “Christmas Tree Galaxy Cluster.”

“Transients are objects in space, like individual stars, that appear to suddenly brighten by orders of magnitudes and then fade away,” said Yan, an associate professor in the Department of Physics and Astronomy. “These transient objects appear bright for only a short period of time and then are gone; it’s like we’re peering through a shifting magnifying glass. Right now, we have this rare chance that nature has given us to get a detailed view of individual stars that are located very far away. While we are currently only able to see the brightest ones, if we do this long enough — and frequently enough — we will be able to determine how many bright stars there are, and how massive they are.”

Using the advanced technological capabilities of the JWST, Yan and his team, including Mizzou graduate student Bangzheng Sun, confirmed what’s causing the galaxy cluster’s “flickering lights” or transients that scientists first saw years ago using NASA’s Hubble Space Telescope.

A color composite image of MACS0416 using the data from four sets of images taken by JWST of the galaxy cluster over a period of 126 days, or about four months. The regions where the transients are found are also marked. Photo courtesy of Bangzheng Sun.

“We’re calling MACS0416 the Christmas Tree Galaxy Cluster, both because it’s so colorful and because of the flickering lights we find within it,” Yan said. “We can see so many transients in certain regions of this area because of a phenomenon known as gravitational lensing, which is magnifying galaxies behind this cluster.”

The team discovered the transients by studying four sets of images taken by JWST of the galaxy cluster over a period of 126 days, or about four months. Yan is particularly excited that two of the transients are supernovae — stars that are at the end of their lifespans — because the team can use them to study the supernovae’s host galaxies.

“The two supernovae and the other twelve extremely magnified stars are of different nature, but they are all important,” Yan said. “We have traced the change in brightness over time through their light curves, and by examining in detail how the light changes over time, we’ll eventually be able to know what kind of stars they are. More importantly, we’ll be able to understand the detailed structure of the magnifying glass and how it relates to dark matter distribution. This is a completely new view of the universe that’s been opened by JWST.”

Direct Writing of a Titania Foam in Microgravity for Photocatalytic Applications

by G. Jacob Cordonier, Kyleigh Anderson, Ronan Butts, Ross O’Hara, Renee Garneau, Nathanael Wimer, John M. Kuhlman, Konstantinos A. Sierros in ACS Applied Materials & Interfaces

Research from West Virginia University students and faculty into how 3D printing works in a weightless environment aims to support long-term exploration and habitation on spaceships, the moon or Mars.

Extended missions in outer space require the manufacture of crucial materials and equipment onsite, rather than transporting those items from Earth. Members of the Microgravity Research Team said they believe 3D printing is the way to make that happen. The team’s recent experiments focused on how a weightless microgravity environment affects 3D printing using titania foam, a material with potential applications ranging from UV blocking to water purification.

“A spacecraft can’t carry infinite resources, so you have to maintain and recycle what you have and 3D printing enables that,” said lead author Jacob Cordonier, a doctoral student in mechanical and aerospace engineering at the WVU Benjamin M. Statler College of Engineering and Mineral Resources. “You can print only what you need, reducing waste. Our study looked at whether a 3D-printed titanium dioxide foam could protect against ultraviolet radiation in outer space and purify water.
“The research also allows us to see gravity’s role in how the foam comes out of the 3D printer nozzle and spreads onto a substrate. We’ve seen differences in the filament shape when printed in microgravity compared to Earth gravity. And by changing additional variables in the printing process, such as writing speed and extrusion pressure, we’re able to paint a clearer image of how all these parameters interact to tune the shape of the filament.”

Cordonier’s co-authors include current and former undergraduate students Kyleigh Anderson, Ronan Butts, Ross O’Hara, Renee Garneau and Nathanael Wimer. Also contributing to the paper were John Kuhlman, professor emeritus, and Konstantinos Sierros, associate professor and associate chair for research in the Department of Mechanical and Aerospace Engineering.

Sierros has overseen the Microgravity Research Team’s titania foam studies since 2016. The work now happens in his WVU labs but originally required taking a ride on a Boeing 727. There, students printed lines of foam onto glass slides during 20-second periods of weightlessness when the jet was at the top of its parabolic flight path.

“Transporting even a kilogram of material in space is expensive and storage is limited, so we’re looking into what is called ‘in-situ resource utilization,’” Sierros said. “We know the moon contains deposits of minerals very similar to the titanium dioxide used to make our foam, so the idea is you don’t have to transport equipment from here to space because we can mine those resources on the moon and print the equipment that’s necessary for a mission.”

Necessary equipment includes shields against ultraviolet light, which poses a threat to astronauts, electronics and other space assets.

“On Earth, our atmosphere blocks a significant part of UV light — though not all of it, which is why we get sunburned,” Cordonier said. “In space or on the moon, there’s nothing to mitigate it besides your spacesuit or whatever coating is on your spacecraft or habitat.”

To measure titania foam’s effectiveness at blocking UV waves, “we would shine light ranging from the ultraviolet wavelengths up to the visible light spectrum,” he explained. “We measured how much light was getting through the titania foam film we had printed, how much got reflected back and how much was absorbed by the sample. We showed the film blocks almost all the UV light hitting the sample and very little visible light gets through. Even at only 200 microns thick, our material is effective at blocking UV radiation.”

Cordonier said the foam also demonstrated photocatalytic properties, meaning that it can use light to promote chemical reactions that can do things like purify air or water. Team member Butts, an undergraduate from Wheeling, led experiments in contact angle testing to analyze how changes in temperature affected the foam’s surface energy. Butts called the research “a different type of challenge that students don’t always get to experience,” and said he especially valued the engagement component.

“Our team gets to do a lot of outreach with young students like the Scouts through the Merit Badge University at WVU. We get to show them what we do here as a way to say, ‘Hey, this is something you could do, too,’” Butts said.

According to Sierros, “We’re trying to integrate research into student careers at an early point. We have a student subgroup that’s purely hardware and they make the 3D printers. We have students leading materials development, automation, data analysis. The undergraduates who have been doing this work with the support of two very competitive NASA grants are participating in the whole research process. They have published peer-reviewed scientific articles and presented at conferences.”

Garneau, a student researcher from Winchester, Virginia, said her dream is for their 3D printer — custom designed to be compact and automated — to take a six-month trip to the International Space Station. That would enable more extensive monitoring of the printing process than was possible during the 20-second freefalls.

“This was an amazing experience,” Garneau said. “It was the first time I participated in a research project that didn’t have predetermined results like what I have experienced in research-based classes. It was really rewarding to analyze the data and come to conclusions that weren’t based on fixed expectations.
“Our approach can help extend space exploration, allowing astronauts to use resources they already have available to them without necessitating a resupply mission.”

The variable source of the plasma sheet during a geomagnetic storm

by L. M. Kistler, K. Asamura, S. Kasahara, Y. Miyoshi, C. G. Mouikis, K. Keika, S. M. Petrinec, M. L. Stevens, T. Hori, S. Yokota, I. Shinohara in Nature Communications

A study from an international team led by researchers from Nagoya University in Japan and the University of New Hampshire in the United States has revealed the importance of the Earth’s upper atmosphere in determining how large geomagnetic storms develop. Their findings reveal the previously underestimated importance of the Earth’s atmosphere. Understanding the factors that cause geomagnetic storms is important because they can have a direct impact on the Earth’s magnetic field such as causing unwanted currents in the power grid and disrupting radio signals and GPS. This research may help predict the storms that will have the greatest consequences.

Scientists have long known that geomagnetic storms are associated with the activities of the Sun. Hot charged particles make up the Sun’s outer layer, the one visible to us. These particles flow out of the Sun creating the ‘solar wind’, and interact with objects in space, such as the Earth. When the particles reach the magnetic field surrounding our planet, known as the magnetosphere, they interact with it. The interactions between the charged particles and magnetic fields lead to space weather, the conditions in space that can affect the Earth and technological systems such as satellites.

An important part of the magnetosphere is the magnetotail. The magnetotail is the part of the magnetosphere that extends away from the Sun, in the direction of the solar wind flow. Inside the magnetotail is the plasma sheet region, which is full of charged particles (plasma). The plasma sheet is important because it is the source region for the particles that get into the inner magnetosphere, creating the current that causes geomagnetic storms.

Solar wind and ionospheric sources of the plasma sheet.

Although the importance of the Sun is well known, an international group of researchers aimed to solve the mystery of how much of the plasma in the magnetosphere comes from Earth and how that contribution changes during a geomagnetic storm. The group was led by Lynn Kistler, Nagoya University Designated Professor and University of New Hampshire Professor (cross-appointment), Yoshizumi Miyoshi, Nagoya University Professor, and Tomoaki Hori, Nagoya University Designated Professor. For their study, they used data from a large geomagnetic storm that happened on September 7–8, 2017. During this time, the Sun released a massive coronal mass ejection that collided with the Earth’s atmosphere, resulting in a huge geomagnetic storm. The impact disrupted the magnetosphere, leading to interference with radio signals, GPS, and precision timing applications.

The researchers retrospectively analyzed the ion transport during this event using data from several space missions, including the NASA/Magnetospheric Multiscale (MMS) mission, the Japanese Arase mission, the ESA/Cluster mission, and the NASA/Wind mission. They distinguished the ions from those of the solar wind and from those of the ionosphere itself.

Using simultaneous measurements of the solar wind composition to track the source changes, they identified substantial changes in the composition and other properties of the near-earth plasma sheet as it developed. These properties of the plasma sheet, such as density, particle energy distribution, and composition, affect the development of the geomagnetic storm.

At the start of the main phase of the storm, the source changed from solar wind dominated to ionosphere dominated. “The most important discovery was that at the beginning of the geomagnetic storm, the plasma changed from mostly solar to mostly ionospheric,” explained Kistler. “This shows that the geomagnetic storm drives more outflow from the Earth’s ionosphere, and that the ionospheric plasma can move quickly throughout the magnetosphere.”

“Overall, our research contributes to understanding the development of geomagnetic storms by showing the importance of Earth’s ionospheric plasma,” she continues. “We found compelling evidence that plasmas from not only the Sun but also the Earth drive a geomagnetic storm. In short, the properties of the plasma sheet (the density, the particle energy distribution, the composition) will affect geomagnetic storms, and these properties are different for different sources.”