ST/ Magma on Mars likely

Paradigm

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Paradigm

31 min readOct 28, 2022

Space biweekly vol.63, 14th October — 28th October

TL;DR

Until now, Mars has been generally considered a geologically dead planet. An international team of researchers now reports that seismic signals indicate vulcanism still plays an active role in shaping the Martian surface.
A recently released set of topography maps provides new evidence for an ancient northern ocean on Mars. The maps offer the strongest case yet that the planet once experienced sea-level rise consistent with an extended warm and wet climate, not the harsh, frozen landscape that exists today.
VLA observations revealed that cosmic rays can play an important role in driving winds that rob galaxies of the gas needed to form new stars. This mechanism may be an important factor in galactic evolution, particularly at earlier times in the history of the universe.
An international team of astrophysicists has made a puzzling discovery while analyzing certain star clusters. The finding challenges Newton’s laws of gravity, the researchers write in their publication. Instead, the observations are consistent with the predictions of an alternative theory of gravity. However, this is controversial among experts.
As part of NASA’s Artemis program to establish a long-term presence on the moon, it aims to build an Artemis base camp that includes a modern lunar cabin, rover and mobile home. This fixed habitat could potentially be constructed with bricks made of lunar regolith and saltwater, thanks to a recent discovery.
An Earth-like planet orbiting an M dwarf — the most common type of star in the universe — appears to have no atmosphere at all. This discovery could cause a major shift in the search for life on other planets.
Using the James Webb Space Telescope to look back in time at the early universe, astronomers discovered a surprise: a cluster of galaxies merging together around a rare red quasar within a massive black hole. The findings offer an unprecedented opportunity to observe how billions of years ago galaxies coalesced into the modern universe.
Astronomers have found a way to determine an asteroid’s interior structure based on how its spin changes during a close encounter with Earth. The tool may improve the aim of future asteroid-targeting missions.
Scientists have compiled 41 solar occultation observations of Saturn’s rings from the Cassini mission. The compilation will inform future investigations of the particle size distribution and composition of Saturn’s rings, key elements to understanding their formation and evolution.
Researchers have developed a new way to use femtosecond laser pulses to fabricate the high-precision ultrathin mirrors required for high-performance x-ray telescopes. The technique could help improve the space-based x-ray telescopes used to capture high-energy cosmic events involved in forming new stars and supermassive black holes.
Upcoming industry events. 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

Tectonics of Cerberus Fossae unveiled by marsquakes

by Simon C. Stähler, Anna Mittelholz, Cleément Perrin, Taichi Kawamura, Doyeon Kim, Martin Knapmeyer, Géraldine Zenhäusern, John Clinton, Domenico Giardini, Philippe Lognonné, W. Bruce Banerdt in Nature Astronomy

Since 2018, when the NASA InSight Mission deployed the SEIS seismometer on the surface of Mars, seismologists and geophysicists at ETH Zurich have been listening to the seismic pings of more than 1,300 marsquakes. Again and again, the researchers registered smaller and larger Mars quakes. A detailed analysis of the quakes’ location and spectral character brought a surprise. With epicentres originating in the vicinity of the Cerberus Fossae — a region consisting of a series of rifts or graben — these quakes tell a new story. A story that suggests vulcanism still plays an active role in shaping the Martian surface.

An international team of researchers, led by ETH Zurich, analysed a cluster of more than 20 recent marsquakes that originated in the Cerberus Fossae graben system. From the seismic data, scientists concluded that the low-frequency quakes indicate a potentially warm source that could be explained by present day molten lava, i.e., magma at that depth, and volcanic activity on Mars. Specifically, they found that the quakes are located mostly in the innermost part of Cerberus Fossae.

When they compared seismic data with observational images of the same area, they also discovered darker deposits of dust not only in the dominant direction of the wind, but in multiple directions surrounding the Cerebus Fossae Mantling Unit. “The darker shade of the dust signifies geological evidence of more recent volcanic activity — perhaps within the past 50,000 years — relatively young, in geological terms,” explains Simon Staehler, the lead author of the paper. Staehler is a Senior Scientist working in the Seismology and Geodynamics group led by Professor Domenico Giardini at the Institute of Geophysics, ETH Zurich.

Exploring Earth’s planetary neighbours is no easy task. Mars is the only planet, other than Earth, in which scientists have ground-based rovers, landers, and now even drones that transmit data. All other planetary exploration, so far, has relied on orbital imagery.

“InSight’s SEIS is the most sensitive seismometer ever installed on another planet,” says Domenico Giardini. “It affords geophysicists and seismologists an opportunity to work with current data showing what is happening on Mars today — both at the surface and in its interior.”

The seismic data, along with orbital images, ensures a greater degree of confidence for scientific inferences.

One of our nearest terrestrial neighbours, Mars is important for understanding similar geological processes on Earth. The red planet is the only one we know of, so far, that has a core composition of iron, nickel, and sulphur that might have once supported a magnetic field. Topographical evidence also indicates that Mars once held vast expanses of water and possibly a denser atmosphere. Even today, scientists have learned that frozen water, although possibly mostly dry ice, still exists on its polar caps.

“While there is much more to learn, the evidence of potential magma on Mars is intriguing,” Anna Mittelholz, Postdoctoral Fellow at ETH Zurich and Harvard University.

Backazimuth estimation from radial vs transverse energy.

Looking at images of the vast dry, dusty Martian landscape it is difficult to imagine that about 3.6 billion years ago Mars was very much alive, at least in a geophysical sense. It spewed volcanic debris for a long enough time to give rise to Tharsis Montes region, the largest volcanic system in our solar system and the Olympus Mons — a volcano nearly three times the elevation of Mount Everest. The quakes coming from the nearby Cerberus Fossae — named for a creature from Greek mythology known as the “hell-hound of Hades” that guards the underworld — suggest that Mars is not quite dead yet. Here the weight of the volcanic region is sinking and forming parallel graben (or rifts) that pull the crust of Mars apart, much like the cracks that appear on the top of a cake while its baking. According to, Staehler “it is possible that what we are seeing are the last remnants of this once active volcanic region or that the magma is right now moving eastward to the next location of eruption.”

Paleogeographic Reconstructions of an Ocean Margin on Mars Based on Deltaic Sedimentology at Aeolis Dorsa

by Benjamin T. Cardenas, Michael P. Lamb in Journal of Geophysical Research: Planets

A recently released set of topography maps provides new evidence for an ancient northern ocean on Mars. The maps offer the strongest case yet that the planet once experienced sea-level rise consistent with an extended warm and wet climate, not the harsh, frozen landscape that exists today.

“What immediately comes to mind as one the most significant points here is that the existence of an ocean of this size means a higher potential for life,” said Benjamin Cardenas, assistant professor of geosciences at Penn State and lead author on the study. “It also tells us about the ancient climate and its evolution. Based on these findings, we know there had to have been a period when it was warm enough and the atmosphere was thick enough to support this much liquid water at one time.”

There has long been debate in the scientific community about whether Mars had an ocean in its low-elevation northern hemisphere, Cardenas explained. Using topography data, the research team was able to show definitive evidence of a roughly 3.5-billion-year-old shoreline with substantial sedimentary accumulation, at least 900 meters thick, that covered hundreds of thousands of square kilometers.

“The big, novel thing that we did in this paper was think about Mars in terms of its stratigraphy and its sedimentary record,” Cardenas said. “On Earth, we chart the history of waterways by looking at sediment that is deposited over time. We call that stratigraphy, the idea that water transports sediment and you can measure the changes on Earth by understanding the way that sediment piles up. That’s what we’ve done here — but it’s Mars.”

The team used software developed by the United States Geological Survey to map data from the National Aeronautics and Space Administration (NASA) and the Mars Orbiter Laser Altimeter. They discovered over 6,500 kilometers of fluvial ridges and grouped them into 20 systems to show that the ridges are likely eroded river deltas or submarine-channel belts, the remnants of an ancient Martian shoreline. Elements of rock formations, such as ridge-system thicknesses, elevations, locations and possible sedimentary flow directions helped the team understand the evolution of the region’s paleogeography. The area that was once ocean is now known as Aeolis Dorsa and contains the densest collection of fluvial ridges on the planet, Cardenas explained.

“The rocks in Aeolis Dorsa capture some fascinating information about what the ocean was like,” he said. “It was dynamic. The sea level rose significantly. Rocks were being deposited along its basins at a fast rate. There was a lot of change happening here.”

Cardenas explained that on Earth, the ancient sedimentary basins contain the stratigraphic records of evolving climate and life. If scientists want to find a record of life on Mars, an ocean as big as the one that once covered Aeolis Dorsa would be the most logical place to start.

“A major goal for the Mars Curiosity rover missions is to look for signs of life,” Cardenas said. “It’s always been looking for water, for traces of habitable life. This is the biggest one yet. It’s a giant body of water, fed by sediments coming from the highlands, presumably carrying nutrients. If there were tides on ancient Mars, they would have been here, gently bringing in and out water. This is exactly the type of place where ancient Martian life could have evolved.”

Cardenas and his colleagues have mapped what they have determined are other ancient waterways on Mars. An upcoming study in the Journal of Sedimentary Research shows various outcrops visited by Curiosity rover were likely sedimentary strata from ancient river bars. Another paper published in Nature Geoscience applies an acoustic imaging technique used to view stratigraphy beneath the Gulf of Mexico’s seafloor to a model of Mars-like basin erosion. The researchers determined the landforms called fluvial ridges, found widely across Mars, are likely ancient river deposits eroded from large basins similar to Aeolis Dorsa.

“The stratigraphy that we’re interpreting here is quite similar to stratigraphy on Earth,” Cardenas said. “Yes, it sounds like a big claim to say we’ve discovered records of large waterways on Mars, but in reality, this is relatively mundane stratigraphy. It’s textbook geology once you recognize it for what it is. The interesting part, of course, is it’s on Mars.”

Cloud-scale Radio Surveys of Star Formation and Feedback in Triangulum Galaxy M 33: VLA Observations

by F. S. Tabatabaei, W. Cotton, E. Schinnerer, R. Beck, A. Brunthaler, K. M. Menten, J. Braine, E. Corbelli, C. Kramer, J. E. Beckman, J. H. Knapen, R. Paladino, E. Koch, A. Camps Farina in Monthly Notices of the Royal Astronomical Society

Astronomers using the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) have discovered an important new clue about how galaxies put the brakes on vigorous episodes of star formation. Their new study of the neighboring galaxy M33 indicates that fast-moving cosmic ray electrons can drive winds that blow away the gas needed to form new stars.

Such winds are responsible for slowing the rate of star formation as galaxies evolve over time. However, shock waves from supernova explosions and energetic, black hole-powered jets of material coming from galactic cores have been considered the primary drivers of those winds. Cosmic rays were thought to be minor contributors, particularly in galaxies like M33 that have regions of prolific star formation.

“We have seen galactic winds driven by cosmic rays in our own Milky Way and the Andromeda galaxy, which have much weaker rates of star formation, but not before in a galaxy such as M33,” said Fatemah Tabatabaei, of the Institute for Research in Fundamental Sciences in Iran.

Structural decomposition of the RC emission from the inner 18′ ×18′ part of M33: a- diffuse disk, b- sources, and c- extended structure at 6.3GHz.

Tabatabaei and an international team of scientists made detailed, multi-wavelength VLA observations of M33, a spiral galaxy nearly 3 million light-years away and part of the Local Group of galaxies that includes the Milky Way. They also used data from previous observations with the VLA, the Effelsberg radio telescope in Germany, and millimeter-wave, visible-light, and infrared telescopes.

Stars much more massive than our Sun speed through their life cycles, ultimately exploding as supernovae. The explosive shock waves can accelerate particles to nearly the speed of light, creating cosmic rays. Enough of these cosmic rays can build pressure that drives winds carrying away the gas needed to continue forming stars.

“The VLA observations indicated that cosmic rays in M33 are escaping the regions where they are born, making them able to drive more extensive winds,” said William Cotton, of the National Radio Astronomy Observatory.

Based on their observations, the astronomers concluded that the numerous supernova explosions and supernova remnants in M33’s giant complexes of prolific star formation made such cosmic ray-driven winds more likely.

“This means that cosmic rays probably are a more general cause of galactic winds, particularly at earlier times in the universe’s history, when star formation was happening at a much higher rate,” Tabatabaei said. She added, “This mechanism thus becomes a more important factor in understanding the evolution of galaxies over time.”

Asymmetrical tidal tails of open star clusters: stars crossing their cluster’s práh† challenge Newtonian gravitation

by Pavel Kroupa, Tereza Jerabkova, Ingo Thies, et al in Monthly Notices of the Royal Astronomical Society

An international team of astrophysicists has made a puzzling discovery while analyzing certain star clusters. The University of Bonn played a major role in the study. The finding challenges Newton’s laws of gravity, the researchers write in their publication. Instead, the observations are consistent with the predictions of an alternative theory of gravity. However, this is controversial among experts.

In their work, the researchers investigated the so-called open star clusters. These are formed when thousands of stars are born within a short time in a huge gas cloud. As they “ignite,” the galactic newcomers blow away the remnants of the gas cloud. In the process, the cluster expands considerably. This creates a loose formation of several dozen to several thousand stars. The weak gravitational forces acting between them hold the cluster together.

“In most cases, open star clusters survive only a few hundred million years before they dissolve,” explains Prof. Dr. Pavel Kroupa of the Helmholtz Institute of Radiation and Nuclear Physics at the University of Bonn. In the process, they regularly lose stars, which accumulate in two so-called “tidal tails.” One of these tails is pulled behind the cluster as it travels through space. The other, in contrast, takes the lead like a spearhead.
“According to Newton’s laws of gravity, it’s a matter of chance in which of the tails a lost star ends up,” explains Dr. Jan Pflamm-Altenburg of the Helmholtz Institute of Radiation and Nuclear Physics. “So both tails should contain about the same number of stars. However, in our work we were able to prove for the first time that this is not true: In the clusters we studied, the front tail always contains significantly more stars nearby to the cluster than the rear tail.”

Graphic — In the star cluster “Hyades” (top), the number of stars (black) in the front tidal tail is significantly larger than those in the rear. In the computer simulation with MOND (below), a similar picture emerges.

Until now, it has been almost impossible to determine from among the millions of stars close to a cluster those that belong to its tails. “To do this, you have to look at the velocity, direction of motion and age of each of these objects,” explains Dr. Tereza Jerabkova. The co-author of the paper, who did her doctorate in Kroupa’s group, recently moved from the European Space Agency (ESA) to the European Southern Observatory in Garching. She developed a method that allowed her to accurately count the stars in the tails for the first time.

“So far, five open clusters have been investigated near us, including four by us,” she says. “When we analyzed all the data, we encountered the contradiction with the current theory. The very precise survey data from ESA’s Gaia space mission were indispensable for this.”

The observational data, in contrast, fit much better with a theory that goes by the acronym MOND (“MOdified Newtonian Dynamics”) among experts.

“Put simply, according to MOND, stars can leave a cluster through two different doors,” Kroupa explains. “One leads to the rear tidal tail, the other to the front. However, the first is much narrower than the second — so it’s less likely that a star will leave the cluster through it. Newton’s theory of gravity, on the other hand, predicts that both doors should be the same width.”

The team calculated the stellar distribution expected according to MOND.

“The results correspond surprisingly well with the observations,” highlights Dr. Ingo Thies, who played a key role in the corresponding simulations. “However, we had to resort to relatively simple computational methods to do this. We currently lack the mathematical tools for more detailed analyses of modified Newtonian dynamics.”

Nevertheless, the simulations also coincided with the observations in another respect: They predicted how long open star clusters should typically survive. And this time span is significantly shorter than would be expected according to Newton’s laws.

“This explains a mystery that has been known for a long time,” Kroupa points out. “Namely, star clusters in nearby galaxies seem to be disappearing faster than they should.”

However, the MOND theory is not undisputed among experts. Since Newton’s laws of gravity would not be valid under certain circumstances, but would have to be modified, this would have far-reaching consequences for other areas of physics as well. “Then again, it solves many of the problems that cosmology faces today,” explains Kroupa, who is also a member of the Transdisciplinary Research Areas “Modelling” and “Matter” at the University of Bonn. The team is now exploring new mathematical methods for even more accurate simulations. They could then be used to find further evidence as to whether the MOND theory is correct or not.

Effect of sintering temperature on microstructure and mechanical properties of molded Martian and Lunar regolith

by Peter Warren, Nandhini Raju, Hossein Ebrahimi, Milos Krsmanovic, Seetha Raghavan, Jayanta Kapat, Ranajay Ghosh in Ceramics International

Using resources found in space to construct off-world structures can drastically reduce the need to transport building materials for programs like Artemis.As part of NASA’s Artemis program to establish a long-term presence on the moon, it aims to build an Artemis base camp that includes a modern lunar cabin, rover and mobile home. This fixed habitat could potentially be constructed with bricks made of lunar regolith and saltwater, thanks to a recent discovery from a team of UCF researchers.

Associate Professor Ranajay Ghosh of UCF’s Department of Mechanical and Aerospace Engineering and his research group found that 3D-printed bricks of lunar regolith can withstand the extreme environments of space and are a good candidate for cosmic construction projects. Lunar regolith is the loose dust, rocks and materials that cover the moon’s surface.

To create the bricks, Ghosh’s team in the Complex Structures and Mechanics of Solids (COSMOS) Lab used a combination of 3D printing and binder jet technology (BJT), an additive manufacturing method that forces out a liquid binding agent onto a bed of powder. In Ghosh’s experiments, the binding agent was saltwater, and the powder was regolith made by UCF’s Exolith Lab.

“BJT is uniquely suitable for ceramic-like materials that are difficult to melt with a laser,” Ghosh says. “Therefore, it has great potential for regolith-based extraterrestrial manufacturing in a sustainable way to produce parts, components and construction structures.”

(Top Left) Sintering oven used for in operation, closed and latched shut (Rapidfire Standard Pro I ®). (Top Right) Oven opened after sintering a set of samples placed on Alumina pads. The oven is heated via two electrical heating coils that run along the sides and top of the sintering oven.(Bottom) Photograph of the cylindrical samples in the 3D-printed halved cylindrical shell PLA molds. The samples are composed of MGS-1 Martian regolith and the binder material is salt water solution. The cylindrical molds are 0.5 inch in diameter and 1 inch in height. The grid line spacing is 1 cm.

The BJT process resulted in weak cylindrical bricks called green parts that were then baked at high temperatures to produce a stronger structure. Bricks baked at lower temperatures crumbled, but those exposed to heat of up to 1200 degrees Celsius were able to withstand pressure of up to 250 million times the Earth’s atmosphere.

Ghosh says the work paves a path for the use of BJT in the construction of materials and structures in space. Their findings also demonstrate that off-world structures can be built using resources found in space, which can drastically reduce the need to transport building materials for missions like Artemis.

“This research contributes to the ongoing debate in space exploration community on finding the balance between in-situ extraterrestrial resource utilization versus material transported from Earth,” Ghosh says. “The further we develop techniques that utilize the abundance of regolith, the more capability we will have in establishing and expanding base camps on the moon, Mars, and other planets in the future.”

GJ 1252b: A Hot Terrestrial Super-Earth with No Atmosphere

by Ian J. M. Crossfield, Matej Malik, Michelle L. Hill, et al in The Astrophysical Journal Letters

An Earth-like planet orbiting an M dwarf — the most common type of star in the universe — appears to have no atmosphere at all. This discovery could cause a major shift in the search for life on other planets.

Because M-dwarfs are so ubiquitous, this discovery means a large number of planets orbiting these stars may also lack atmospheres and therefore are unlikely to harbor living things. The work that led to the revelations about the no-atmosphere planet, named GJ 1252b. This planet orbits its star twice during the course of a single day on Earth. It is slightly larger than Earth, and it is much closer to its star than Earth is to the sun, making GJ 1252b intensely hot as well as inhospitable.

“The pressure from the star’s radiation is immense, enough to blow a planet’s atmosphere away,” said Michelle Hill, UC Riverside astrophysicist and study co-author.

Earth also loses some of its atmosphere over time because of the sun, but volcanic emissions and other carbon cycling processes make the loss barely noticeable by helping replenish what is lost. However, in greater proximity to a star, a planet cannot keep replenishing the amount being lost.

Spitzer 4.5 μm photometry and secondary eclipse fit (top) and residuals to the fit (bottom). The photometry is shown after detrending for systematic effects, combining the photometry from all 10 eclipse visits, and binning down to a two-minute cadence.

In our solar system, this is the fate of Mercury. It does have an atmosphere, but one that is extremely thin, made up of atoms blasted off its surface by the sun. The extreme heat of the planet causes these atoms to escape into space. To determine that GJ 1252b lacks an atmosphere, astronomers measured infrared radiation from the planet as its light was obscured during a secondary eclipse. This type of eclipse occurs when a planet passes behind a star and the planet’s light, as well as light reflected from its star, is blocked. The radiation revealed the planet’s scorching daytime temperatures, estimated to reach 2,242 degrees Fahrenheit — so hot that gold, silver, and copper would all melt on the planet. The heat, coupled with assumed low surface pressure, led the researchers to believe there’s no atmosphere.

Even with a tremendous amount of carbon dioxide, which traps heat, the researchers concluded GJ 1252b would still not be able to hold on to an atmosphere. “The planet could have 700 times more carbon than Earth has, and it still wouldn’t have an atmosphere. It would build up initially, but then taper off and erode away,” said Stephen Kane, UCR astrophysicist and study co-author. M dwarf stars tend to have more flares and activity than the sun, further reducing the likelihood that planets closely surrounding them could hold on to their atmospheres.

“It’s possible this planet’s condition could be a bad sign for planets even further away from this type of star,” Hill said. “This is something we’ll learn from the James Webb Space Telescope, which will be looking at planets like these.”

There are 5,000 stars in Earth’s solar neighborhood, most of them M dwarfs. Even if planets orbiting them can be ruled out entirely, there are still roughly 1,000 stars similar to the sun that could be habitable.

“If a planet is far enough away from an M dwarf, it could potentially retain an atmosphere. We cannot conclude yet that all rocky planets around these stars get reduced to Mercury’s fate,” Hill said. “I remain optimistic.”

First results from the JWST Early Release Science Program Q3D: Turbulent times in the life of a z∼3 extremely red quasar revealed by NIRSpec IFU

by Dominika Wylezalek, Andrey Vayner, David S. N. Rupke, et al, submitted to arXiv

Using the James Webb Space Telescope to look back in time at the early universe, astronomers discovered a surprise: a cluster of galaxies merging together around a rare red quasar within a massive black hole. The findings by Johns Hopkins University and an international team offer an unprecedented opportunity to observe how billions of years ago galaxies coalesced into the modern universe.

“We think something dramatic is about to happen in these systems,” said co-author Andrey Vayner, a Johns Hopkins postdoctoral fellow who studies the evolution of galaxies. “The galaxy is at this perfect moment in its lifetime, about to transform and look entirely different in a few billion years.”

The James Webb Space Telescope, launched last December by NASA, the European Space Agency, and the Canadian Space Agency, is the largest, most powerful telescope ever sent into space. Its initial general observations were revealed in July, but this quasar imagery is one of just 13 “early look” projects selected through a highly competitive global competition to decide where the telescope is pointed during its first months of operation.

A Hubble image of the quasar and the same area viewed with the James Webb Space Telescope. The Webb image shows multiple galaxies coalescing, with each color representing a different velocity: Red is moving away from us. Blue is moving toward us.

In Baltimore, the Johns Hopkins team heard their chosen target would be observed within days of President Biden’s unveiling of the Webb’s debut pictures on July 11, so stayed close to their computers. That following summer Saturday, Vayner and graduate student Yuzo Ishikawa were repeatedly refreshing the Webb database when suddenly the data arrived, leading to a hastily assembled multinational team confab on Sunday to try to make sense of the jaw-droppingly detailed raw images.

Although earlier observations of this area by NASA/ESA Hubble Space Telescope and the Near-Infrared Integral Field Spectrometer instrument on the Gemini-North telescope pinpointed the quasar and hinted at the possibility of a galaxy in transition, no one suspected that with Webb’s crisp imaging they’d see multiple galaxies, at least three, swirling the region.

“With previous images we thought we saw hints that the galaxy was possibly interacting with other galaxies on the path to merger because their shapes get distorted in the process and we thought we maybe saw that,” said co-principal investigator Nadia L. Zakamska, a Johns Hopkins astrophysicist who helped conceive the project back in 2017 with then-Johns Hopkins postdoc Dominika Wylezalek, who’s now the group leader at the University of Heidelberg. “But after we got the Webb data, I was like, ‘I have no idea what we’re even looking at here, what is all this stuff!’ We spent several weeks just staring and staring at these images.”

The Webb revealed at least three galaxies moving incredibly fast, suggesting a large amount of mass is present. The team believes this could be one of the densest known areas of galaxy formation in the early universe. Because light takes time to travel to us, when we look at objects like this one in the very distant regions of the universe, we’re seeing light that was emitted about 11.5 billion years ago, or from the earliest stages of the universe’s evolution. Massive galaxy swarms like this one were likely common then, Zakamska said.

“It’s super exciting to be one of the first people to see this really cool object,” said Ishikawa, who contributed to the interpretation of the galaxy swarm.

Even Vayner, who’d dreamed of using Webb data since he first heard about the telescope as an undergraduate more than a decade ago, and thought he knew what to expect, was shocked to see his long-studied spot in the universe revealed with such clarity.

“It really will transform our understanding of this object,” said Vayner, who was instrumental in adapting the raw Webb data for scientific analysis.

The blindingly bright quasar, fueled by what Zakamska calls a “monster” black hole at the center of the galactic swirl, is a rare “extremely red” quasar, about 11.5 billion years old and one of the most powerful ever seen from such distance. It’s essentially a black hole in formation, Vayner said, eating the gas around it and growing in mass. The clouds of dust and gas between Earth and the glowing gas near the black hole make the quasar appear red.

The team is already working on follow-up observations into this unexpected galaxy cluster, hoping to better understand how dense, chaotic galaxy clusters form, and how it is affected by supermassive black hole at its heart.

“What you see here is only a small subset of what’s in the data set,” Zakamska said. “There’s just too much going on here so we first highlighted what really is the biggest surprise. Every blob here is a baby galaxy merging into this mommy galaxy and the colors are different velocities and the whole thing is moving in an extremely complicated way. We can now start to untangle the motions.”

Constraining the interiors of asteroids through close encounters

by Jack T Dinsmore, Julien de Wit in Monthly Notices of the Royal Astronomical Society

NASA hit a bullseye in late September with DART, the Double Asteroid Redirection Test, which flew a spacecraft straight at the heart of a nearby asteroid. The one-way kamikaze mission smashed into the stadium-sized space rock and successfully reset the asteroid’s orbit. DART was the first test of a planetary defense strategy, demonstrating that scientists could potentially deflect an asteroid headed for Earth.

Now MIT researchers have a tool that may improve the aim of future asteroid-targeting missions. The team has developed a method to map an asteroid’s interior structure, or density distribution, based on how the asteroid’s spin changes as it makes a close encounter with more massive objects like the Earth.

Knowing how the density is distributed inside an asteroid could help scientists plan the most effective defense. For instance, if an asteroid were made of relatively light and uniform matter, a DART-like spacecraft could be aimed differently than if it were deflecting an asteroid with a denser, less balanced interior.

“If you know the density distribution of the asteroid, you could hit it at just the right spot so it actually moves away,” says Jack Dinsmore ’22, who developed the new asteroid-mapping technique as an MIT undergraduate majoring in physics.

PPDs extracted from synthetic encounter data for the asymmetric reference asteroid.

The team is eager to apply the method to Apophis, a near-Earth asteroid that is estimated to pose a significant hazard if it were to make impact. Scientists have ruled out the likelihood of a collision during Apophis’ next flybys for at least a century. Beyond that, their forecasts grow fuzzy.

“Apophis will miss Earth in 2029, and scientists have cleared it for its next few encounters, but we can’t clear it forever,” says Dinsmore, who is now a graduate student at Stanford University. “So, it’s good to understand the nature of this particular asteroid, because if we ever need to redirect it, it’s important to understand what it’s made of.”

Dinsmore and Julien de Wit, assistant professor in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS), detail their new method in a study. The seeds of the team’s asteroid-mapping method grew out of an MIT class Dinsmore took last year, taught by de Wit. The class, 12.401 (Essentials of Planetary Sciences), introduces the basic principles and formation mechanisms of planets, asteroids, and other objects in the solar system. As a final project, Dinsmore explored how an asteroid behaves during a close encounter. In class, he wrote a code to simulate various shapes and sizes of asteroids as well as how their orbital and spin dynamics change when influenced by the gravitational pull of a more massive object like the Earth.

“I initially just tried to ask, what happens when an asteroid passes by Earth? Does it respond at all? Because I wasn’t sure,” Dinsmore recalls. “And the answer is, it does, in a way that depends very strongly on the shape and physical properties of the asteroid.”

That initial realization prompted another question: Could the dynamics of an asteroid’s close encounter be used to predict not just its shape and size, but also its internal makeup? To get at an answer, Dinsmore continued the project with de Wit, through the MIT Undergraduate Research Opportunities Program (UROP), which enables students to perform original research with a faculty member.

He and de Wit took a deeper dive into the dynamics of a close encounter, writing out a more complex code, which they used to simulate a zoo of different asteroids, each with a different size, shape, and internal composition, or distribution of density. They then ran the simulation forward to see how each asteroid’s spin should wobble or shift as it passes close to an object of a certain mass and gravitational pull.

“It’s similar to how you can tell the difference between a raw and boiled egg,” de Wit offers. “If you spin the egg, the egg responds and spins differently depending on its interior properties. The same goes for an asteroid during a close encounter: You can get a grasp of what’s happening on the inside just by looking on how it responds to the strong gravitational forces it experiences during a flyby.”

Cross-sectional slices of the extracted distribution (left) and true distribution (right) of the asymmetric reference asteroid.

The team is presenting their results in a new software “toolkit,” which they name AIME, for Asteroid Interior Mapping from Encounters (the acronym also translates as “love” in French). The software can be used to reconstruct the internal density distribution of an asteroid, from observations of its spin change during a close encounter. The researchers say that, if scientists can take more detailed measurements of asteroids and their spin dynamics during close encounters, these measurements could be used to improve AIME’s reconstructions of asteroid interiors. Their best chance, they say, may come with Apophis. During its forthcoming close encounters, de Wit and Dinsmore hope astronomers will point their telescopes at the space rock to measure its size, shape, and spin evolution as it streaks past. They could then feed these measurements into AIME to find a match — a simulated asteroid with the same size, shape, and spin dynamics as Apophis, that also relates to a particular interior density distribution.

“Then, with AIME, you could publish a density map that most likely represents Apophis’ interior,” Dinsmore says.
“Understanding the interior properties of asteroids helps us understand the extent to which close encounters could be of concern, and how to deal with them, as well as where they formed and how they got here,” de Wit adds. “Now with this framework, there’s a new way of getting a look inside an asteroid.”

Solar occultation observations of Saturn’s rings with Cassini UVIS

by S.G. Jarmak, T.M. Becker, J.E. Colwell, R.G. Jerousek, L.W. Esposito in Icarus

Southwest Research Institute scientists have compiled 41 solar occultation observations of Saturn’s rings from the Cassini mission. The compilation, published recently in the scientific journal Icarus, will inform future investigations of the particle size distribution and composition of Saturn’s rings, key elements to understanding their formation and evolution.

“For nearly two decades, NASA’s Cassini spacecraft shared the wonders of Saturn and its family of icy moons and signature rings, but we still don’t definitively know the origins of the ring system,” said Dr. Stephanie Jarmak, a researcher in the SwRI Space Science Division. “Evidence indicates that the rings are relatively young and could have formed from the destruction of an icy satellite or a comet. However, to support any one origin theory, we need to have a good idea of the size of particles making up the rings.”

Cassini’s Ultraviolet Imaging Spectrograph (UVIS) was uniquely sensitive to some of the smallest ring particles, particularly with the observations it made in the extreme ultraviolet wavelength.

Geometric parameters for occultation observations.

To determine the size of the ring particles, UVIS observed them when the instrument was pointed at the Sun, looking through the rings in what is known as a solar occultation. Ring particles partially blocked the path of the light, providing a direct measurement of the optical depth, a key parameter for determining the size and composition of the ring particles.

“Given the wavelength of the light coming from the Sun, these observations gave us insight into the smallest particle sizes with Saturn’s rings,” Jarmak said. “UVIS can detect dust particles at the micron level, helping us understand the origin, collisional activity and destruction of the ring particles within the system.”

The compilation also delves into the variations in the optical depth of occultation observations, which can help determine particle size and composition. During an occultation, light emitted by a background source, such as the Sun, is absorbed and scattered by the particles in the light’s path. The amount of light blocked by ring particles provides a direct measurement of the ring optical depth.

Chord occultation geometry visualizations.

Including optical depth is vital to understanding the structure of the rings. The research measured the optical depth as a function of the viewing geometry, which refers to the observation angles of the ring system with respect to the Cassini spacecraft. As light passing through the rings changes at various angles, scientists can form a picture of the rings’ structures.

“Ring systems around giant planets also provide test beds for investigating fundamental physical properties and processes in our solar system in general,” Jarmak said. “These particles are thought to result from objects colliding and forming in a disk and building up larger particles. Understanding how they form these ring systems could help us understand how planets form as well.”

Femtosecond laser micromachining for stress-based figure correction of thin mirrors

by Heng Zuo, Ralf Heilmann, Mark Schattenburg in Optica

Researchers have developed a new way to use femtosecond laser pulses to fabricate the high-precision ultrathin mirrors required for high-performance x-ray telescopes. The technique could help improve the space-based x-ray telescopes used to capture high-energy cosmic events involved in forming new stars and supermassive black holes.

“Detecting cosmic x-rays is a crucial piece of our exploration of the universe that unveils the high-energy events that permeate our universe but are not observable in other wavebands,” said research team leader Heng Zuo, who performed the research at MIT Kavli Institute for Astrophysics and Space Research and is now at the University of New Mexico. “The technologies our group developed will help telescopes obtain sharp images of astronomical x-rays that can answer many intriguing science questions.”

X-ray telescopes orbit above the Earth’s atmosphere and contain thousands of thin mirrors that must each have a precisely curved shape and be carefully aligned with respect to all the other mirrors. The researchers describe how they used femtosecond laser micromachining to bend these ultrathin mirrors into a precise shape and correct errors that can arise in the fabrication process.

“It is difficult to make ultra-thin mirrors with an exact shape because the fabrication process tends to severely bend the thin material,” said Zuo. “Also, telescope mirrors are usually coated to increase reflectivity, and these coatings typically deform the mirrors further. Our techniques can address both challenges.”

Illustration of the two stressed film figuring methods for correcting thin mirrors using ultrafast lasers.

New ways to fabricate ultra-precise and high-performance x-ray mirrors for telescopes are needed as new mission concepts continue to push the limits of x-ray imaging. For example, NASA’s Lynx X-ray Surveyor concept will have the most powerful x-ray optic ever conceived and will require the manufacture of a large number of ultra-high-resolution mirrors.

To meet this need, Zuo’s research group combined femtosecond laser micromachining with a previously developed technique called stress-based figure correction. Stress-based figure correction exploits the bendability of thin mirrors by applying a deformable film to the mirror substrate to adjust its stress states and induce controlled bending.

The technique involves selectively removing regions of a stressed film grown onto the back surface of a flat mirror. The researchers selected femtosecond lasers to accomplish this because the pulses produced by these lasers can create extremely precise holes, channels and marks with little collateral damage. Also, the high repetition rates of these lasers allow faster machining speeds and throughput compared to traditional methods. This could help speed up fabrication for the large numbers of ultra-thin mirrors required for next-generation x-ray telescopes.

Laser micromachining system setup at Advanced Optowave Corporation.

To carry out the new approach the researchers first had to determine exactly how laser micromachining changes the mirror’s surface curvature and stress states. Then they measured the initial mirror shape and created a map of the stress correction necessary to create the desired shape. They also developed a multi-pass correction scheme that uses a feedback loop to repeatedly reduce errors until an acceptable mirror profile is achieved.

“Our experimental results showed that patterned removal of periodic holes leads to equibiaxial (bowl-shaped) stress states, while fine-pitched oriented removal of periodic troughs generates non-equibiaxial (potato-chip-shaped) stress components,” said Zuo. “Combining these two features with proper rotation of the trough orientation we can create a variety of stress states that can, in principle, be used to correct for any type of error in the mirrors.”

In this work, the researchers demonstrated the new technique on flat silicon wafers using regular patterns. To correct real x-ray astronomy telescope mirrors, which are curved in two directions, the researchers are developing a more complex optical setup for 3D movement of the substrates.