ST/ Venus has almost no water: A new study reveals why

Paradigm

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Paradigm

30 min readMay 16, 2024

Space biweekly vol.97, 26th April — 16th May

TL;DR

Venus may have had as much water as Earth billions of years ago, but it’s mostly vanished now.
Early quasar observations shed light on rapid supermassive black hole growth.
New Jupiter findings could clarify Earth’s space environment and solar system dynamics.
Computer simulations support the existence of dark matter.
A ‘cosmic glitch’ in gravity explains peculiar cosmic behavior.
NASA’s James Webb Space Telescope’s life detection claim faces scrutiny.
Astrophysicists make progress in understanding space plasma turbulence.
The telescope captures unprecedented infrared images of the Horsehead Nebula.
ESA’s INTEGRAL detects a gamma-ray burst from M82, linked to a magnetar flare.
Ryugu asteroid samples reveal surface changes from micrometeoroid impacts.
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

Venus water loss is dominated by HCO+ dissociative recombination

by M. S. Chaffin, E. M. Cangi, B. S. Gregory, R. V. Yelle, J. Deighan, R. D. Elliott, H. Gröller in Nature

Planetary scientists at the University of Colorado Boulder have discovered how Venus, Earth’s scalding and uninhabitable neighbor, became so dry.

The new study fills in a big gap in what the researchers call “the water story on Venus.” Using computer simulations, the team found that hydrogen atoms in the planet’s atmosphere go whizzing into space through a process known as “dissociative recombination” — causing Venus to lose roughly twice as much water every day compared to previous estimates. The results could help to explain what happens to water in a host of planets across the galaxy.

“Water is really important for life,” said Eryn Cangi, a research scientist at the Laboratory for Atmospheric and Space Physics (LASP) and co-lead author of the new paper. “We need to understand the conditions that support liquid water in the universe, and that may have produced the very dry state of Venus today.”

Venus, she added, is positively parched. If you took all the water on Earth and spread it over the planet like jam on toast, you’d get a liquid layer roughly 3 kilometers (1.9 miles) deep. If you did the same thing on Venus, where all the water is trapped in the air, you’d wind up with only 3 centimeters (1.2 inches), barely enough to get your toes wet.

“Venus has 100,000 times less water than the Earth, even though it’s basically the same size and mass,” said Michael Chaffin, co-lead author of the study and a research scientist at LASP.

In Venus’ upper atmosphere, hydrogen atoms, orange, whiz into space, leaving behind carbon monoxide molecules, blue and purple. (Credit: Aurore Simonnet/LASP/CU Boulder)

In the current study, the researchers used computer models to understand Venus as a gigantic chemistry laboratory, zooming in on the diverse reactions that occur in the planet’s swirling atmosphere. The group reports that a molecule called HCO+ (an ion made up of one atom each of hydrogen, carbon and oxygen) high in Venus’ atmosphere may be the culprit behind the planet’s escaping water. For Cangi, co-lead author of the research, the findings reveal new hints about why Venus, which probably once looked almost identical to Earth, is all but unrecognizable today.

“We’re trying to figure out what little changes occurred on each planet to drive them into these vastly different states,” said Cangi, who earned her doctorate in astrophysical and planetary sciences at CU Boulder in 2023.

Venus, she noted, wasn’t always such a desert. Scientists suspect that billions of year ago during the formation of Venus, the planet received about as much water as Earth. At some point, catastrophe struck. Clouds of carbon dioxide in Venus’ atmosphere kicked off the most powerful greenhouse effect in the solar system, eventually raising temperatures at the surface to a roasting 900 degrees Fahrenheit. In the process, all of Venus’ water evaporated into steam, and most drifted away into space. But that ancient evaporation can’t explain why Venus is as dry as it is today, or how it continues to lose water to space.

“As an analogy, say I dumped out the water in my water bottle. There would still be a few droplets left,” Chaffin said.

On Venus, however, almost all of those remaining drops also disappeared. The culprit, according to the new work, is elusive HCO+.

Chaffin and Cangi explained that in planetary upper atmospheres, water mixes with carbon dioxide to form this molecule. In previous research, the researchers reported that HCO+ may be responsible for Mars losing a big chunk of its water. Here’s how it works on Venus: HCO+ is produced constantly in the atmosphere, but individual ions don’t survive for long. Electrons in the atmosphere find these ions, and recombine to split the ions in two. In the process, hydrogen atoms zip away and may even escape into space entirely — robbing Venus of one of the two components of water.

In the new study, the group calculated that the only way to explain Venus’ dry state was if the planet hosted larger than expected volumes of HCO+ in its atmosphere. There is one twist to the team’s findings. Scientists have never observed HCO+ around Venus. Chaffin and Cangi suggest that’s because they’ve never had the instruments to properly look. While dozens of missions have visited Mars in recent decades, far fewer spacecraft have traveled to the second planet from the sun. None have carried instruments capable of detecting the HCO+ that powers the team’s newly discovered escape route.

“One of the surprising conclusions of this work is that HCO+ should actually be among the most abundant ions in the Venus atmosphere,” Chaffin said.

In recent years, however, a growing number of scientists have set their sights on Venus. NASA’s planned Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging (DAVINCI) mission, for example, will drop a probe through the planet’s atmosphere all the way to the surface. It’s scheduled to launch by the end of the decade.

DAVINCI won’t be able to detect HCO+, either, but the researchers are hopeful that a future mission might — revealing another key piece of the story of water on Venus.

“There haven’t been many missions to Venus,” Cangi said. “But newly planned missions will leverage decades of collective experience and a flourishing interest in Venus to explore the extremes of planetary atmospheres, evolution and habitability.”

EIGER. V. Characterizing the Host Galaxies of Luminous Quasars at z ≳ 6

by Minghao Yue, Anna-Christina Eilers, Robert A. Simcoe, Ruari Mackenzie, Jorryt Matthee, Daichi Kashino, Rongmon Bordoloi, Simon J. Lilly, Rohan P. Naidu in The Astrophysical Journal

MIT astronomers have observed the elusive starlight surrounding some of the earliest quasars in the universe. The distant signals, which trace back more than 13 billion years to the universe’s infancy, are revealing clues to how the very first black holes and galaxies evolved.

Quasars are the blazing centers of active galaxies, which host an insatiable supermassive black hole at their core. Most galaxies host a central black hole that may occasionally feast on gas and stellar debris, generating a brief burst of light in the form of a glowing ring as material swirls in toward the black hole.

Quasars, by contrast, can consume enormous amounts of matter over much longer stretches of time, generating an extremely bright and long-lasting ring — so bright, in fact, that quasars are among the most luminous objects in the universe. Because they are so bright, quasars outshine the rest of the galaxy in which they reside. But the MIT team was able for the first time to observe the much fainter light from stars in the host galaxies of three ancient quasars.

Based on this elusive stellar light, the researchers estimated the mass of each host galaxy, compared to the mass of its central supermassive black hole. They found that for these quasars, the central black holes were much more massive relative to their host galaxies, compared to their modern counterparts. The findings may shed light on how the earliest supermassive black holes became so massive despite having a relatively short amount of cosmic time in which to grow. In particular, those earliest monster black holes may have sprouted from more massive “seeds” than more modern black holes did.

“After the universe came into existence, there were seed black holes that then consumed material and grew in a very short time,” says study author Minghao Yue, a postdoc in MIT’s Kavli Institute for Astrophysics and Space Research. “One of the big questions is to understand how those monster black holes could grow so big, so fast.”
“These black holes are billions of times more massive than the sun, at a time when the universe is still in its infancy,” says study author Anna-Christina Eilers, assistant professor of physics at MIT. “Our results imply that in the early universe, supermassive black holes might have gained their mass before their host galaxies did, and the initial black hole seeds could have been more massive than today.”

Eilers’ and Yue’s co-authors include MIT Kavli Director Robert Simcoe, MIT Hubble Fellow and postdoc Rohan Naidu, and collaborators in Switzerland, Austria, Japan, and at North Carolina State University.

The PSFs and the relative error maps, estimated from isolated bright stars in the images. These cutouts have sizes of 3'’ × 3'’, and the integrated fluxes of the PSFs are normalized. The relative error is larger for brighter pixels, and the central bright pixels have relative errors up to ∼30%.

A quasar’s extreme luminosity has been obvious since astronomers first discovered the objects in the 1960s. They assumed then that the quasar’s light stemmed from a single, star-like “point source.” Scientists designated the objects “quasars,” as a portmanteau of a “quasi-stellar” object. Since those first observations, scientists have realized that quasars are in fact not stellar in origin but emanate from the accretion of intensely powerful and persistent supermassive black holes sitting at the center of galaxies that also host stars, which are much fainter in comparison to their dazzling cores.

It’s been extremely challenging to separate the light from a quasar’s central black hole from the light of the host galaxy’s stars. The task is a bit like discerning a field of fireflies around a central, massive searchlight. But in recent years, astronomers have had a much better chance of doing so with the launch of NASA’s James Webb Space Telescope (JWST), which has been able to peer farther back in time, and with much higher sensitivity and resolution, than any existing observatory.

In their new study, Yue and Eilers used dedicated time on JWST to observe six known, ancient quasars, intermittently from the fall of 2022 through the following spring. In total, the team collected more than 120 hours of observations of the six distant objects.

“The quasar outshines its host galaxy by orders of magnitude. And previous images were not sharp enough to distinguish what the host galaxy with all its stars looks like,” Yue says. “Now for the first time, we are able to reveal the light from these stars by very carefully modeling JWST’s much sharper images of those quasars.”

A James Webb Telescope image shows the J0148 quasar circled in red. Two insets show, on top, the central black hole, and on bottom, the stellar emission from the host galaxy. Credits: Courtesy of the researchers; NASA.

The team took stock of the imaging data collected by JWST of each of the six distant quasars, which they estimated to be about 13 billion years old. That data included measurements of each quasar’s light in different wavelengths. The researchers fed that data into a model of how much of that light likely comes from a compact “point source,” such as a central black hole’s accretion disk, versus a more diffuse source, such as light from the host galaxy’s surrounding, scattered stars.

Through this modeling, the team teased apart each quasar’s light into two components: light from the central black hole’s luminous disk and light from the host galaxy’s more diffuse stars. The amount of light from both sources is a reflection of their total mass. The researchers estimate that for these quasars, the ratio between the mass of the central black hole and the mass of the host galaxy was about 1:10. This, they realized, was in stark contrast to today’s mass balance of 1:1,000, in which more recently formed black holes are much less massive compared to their host galaxies.

“This tells us something about what grows first: Is it the black hole that grows first, and then the galaxy catches up? Or is the galaxy and its stars that first grow, and they dominate and regulate the black hole’s growth?” Eilers explains. “We see that black holes in the early universe seem to be growing faster than their host galaxies. That is tentative evidence that the initial black hole seeds could have been more massive back then.”
“There must have been some mechanism to make a black hole gain their mass earlier than their host galaxy in those first billion years,” Yue adds. “It’s kind of the first evidence we see for this, which is exciting.”

Signatures of Open Magnetic Flux in Jupiter’s Dawnside Magnetotai

by P. A. Delamere, R. J. Wilson, S. Wing, A. R. Smith, B. Mino, C. Spitler, P. Damiano, K. Sorathia, A. Sciola, J. Caggiano, J. R. Johnson, X. Ma, F. Bagenal, B. Zhang, F. Allegrini, R. Ebert, G. Clark, O. Brambles in AGU Advances

New discoveries about Jupiter could lead to a better understanding of Earth’s own space environment and influence a long-running scientific debate about the solar system’s largest planet.

“By exploring a larger space such as Jupiter, we can better understand the fundamental physics governing Earth’s magnetosphere and thereby improve our space weather forecasting,” said Peter Delamere, a professor at the UAF Geophysical Institute and the UAF College of Natural Science and Mathematics. “We are one big space weather event from losing communication satellites, our power grid assets, or both”.

Space weather refers to disturbances in the Earth’s magnetosphere caused by interactions between the solar wind and the Earth’s magnetic field. These are generally associated with solar storms and the sun’s coronal mass ejections, which can lead to magnetic fluctuations and disruptions in power grids, pipelines and communication systems.

Delamere and a team of co-authors detailed their findings about Jupiter’s magnetosphere in a recent paper. Geophysical Institute research associate professor Peter Damiano, UAF graduate student researchers Austin Smith and Chynna Spitler, and former student Blake Mino are among the co-authors. Delamere’s research shows that our solar system’s largest planet has a magnetosphere consisting of largely closed magnetic field lines at its polar regions but including a crescent-shaped area of open field lines. The magnetosphere is the shield that some planets have that deflects much of the solar wind.

Topological classes of Jovian magnetic field lines.

The debate over open versus closed at the poles has raged for more than 40 years. An open magnetosphere refers to a planet having some open-ended magnetic field lines near its poles. These are previously closed lines that have been broken apart by the solar wind and left to extend into space without re-entering the planet. This creates regions on Jupiter where the solar wind, which carries some of the sun’s magnetic field lines, directly interacts with the planet’s ionosphere and atmosphere.

Solar particles moving toward a planet on open field lines do not cause the aurora, which largely occurs on closed field lines. However, the energy and momentum of solar wind particles on open field lines does transfer to the closed system. Earth has a largely open magnetosphere at its poles, with aurora occurring on closed field lines.. It is the transferred energy on those open lines that can disrupt power grids and communications. In order to study Jupiter’s magnetosphere, Delamere ran a variety of models using data acquired by the NASA Juno spacecraft, which entered Jupiter’s orbit in 2016 and has an elliptical polar orbit.

“We never had data from the polar regions, so Juno has been transformative in terms of the planet’s auroral physics and helping further the discussion about its magnetic field lines,” Delamere said.

The debate began with the 1979 flybys of Jupiter by NASA’s Voyager 1 and Voyager 2. That data led many to believe that the planet had a generally open magnetosphere at its poles.Other scientists argued that Jupiter’s auroral activity, which is much different from Earth’s, indicated the planet had a mostly closed magnetosphere at the poles. Delamere, a longtime researcher of Jupiter’s magnetic field, published a paper supporting that view in 2010.

In 2021, he was a co-author on a paper by Binzheng Zhang of the University of Hong Kong that suggested through modeling that Jupiter’s magnetosphere had two regions of open magnetic field lines at its poles. The model shows one set of open-ended field lines emerging from the poles and trailing outward behind the planet in the magnetotail, the narrow teardrop-shaped portion of the magnetosphere pointing away from the sun. The other set emerges from Jupiter’s poles and goes off to the sides into space, carried by the solar wind.

“The Zhang result provided a plausible explanation for the open field line regions,” Delamere said. “And this year we provided the compelling evidence in the Juno data to support the model result.
“It is a major validation of the Zhang paper,” he said.

Delamere said it’s important to study Jupiter to better understand Earth.

“In the big picture, Jupiter and Earth represent opposite ends of the spectrum — open versus closed field lines,” he said. “To fully understand magnetospheric physics, we need to understand both limits.”

Delamere’s evidence came via an instrument on the Juno spacecraft that revealed a polar area where ions flowed in a direction opposite Jupiter’s rotation. Subsequent modeling showed a similar ion flow in the same area — and near the open field lines proposed in the 2021 paper by Zhang and Delamere.

“The ionized gas on [closed] magnetic field lines connected to Jupiter’s northern and southern hemispheres rotates with the planet,” Delamere’s new paper concludes, “while ionized gas on [open] field lines that connect to the solar wind move with the solar wind.”

Delamere writes that the polar location of open magnetic field lines “may represent a characteristic feature of rotating giant magnetospheres for future exploration.”

Hooks & Bends in the radial acceleration relation: discriminatory tests for dark matter and MOND

by Francisco J Mercado, James S Bullock, Jorge Moreno, Michael Boylan-Kolchin, Philip F Hopkins, Andrew Wetzel, Claude-André Faucher-Giguère, Jenna Samuel in Monthly Notices of the Royal Astronomical Society

Computer simulations by astronomers support the idea that dark matter — matter that no one has yet directly detected but which many physicists think must be there to explain several aspects of the observable universe — exists, according to the researchers, who include those at the University of California, Irvine.

The work addresses a fundamental debate in astrophysics — does invisible dark matter need to exist to explain how the universe works the way it does, or can physicists explain how things work based solely on the matter we can directly observe? Currently, many physicists think something like dark matter must exist to explain the motions of stars and galaxies.

“Our paper shows how we can use real, observed relationships as a basis to test two different models to describe the universe,” said Francisco Mercado, lead author and recent Ph.D. graduate from the UC Irvine Department of Physics & Astronomy who is now a postdoctoral scholar at Pomona College. “We put forth a powerful test to discriminate between the two models.”

The test involved running computer simulations with both types of matter — normal and dark — to explain the presence of intriguing features measured in real galaxies. The features in galaxies the team found “are expected to appear in a universe with dark matter but would be difficult to explain in a universe without it,” said Mercado. “We show that such features appear in observations of many real galaxies. If we take these data at face value, this reaffirms the position of the dark matter model as the one that best describes the universe we live in.”

These features Mercado noted describe patterns in the motions of stars and gas in galaxies that seem to only be possible in a universe with dark matter.

*Schematic examples: a standard RAR and a downward hook*.

“Observed galaxies seem to obey a tight relationship between the matter we see and the inferred dark matter we detect, so much so that some have suggested that what we call dark matter is really evidence that our theory of gravity is wrong,” said co-author James Bullock, professor of physics at UCI and dean of the UCI School of Physical Sciences. “What we showed is that not only does dark matter predict the relationship, but for many galaxies it can explain what we see more naturally than modified gravity. I come away even more convinced that dark matter is the right model.”

The features also appear in observations made by proponents of a dark matter-free universe. “The observations we examined — the very observations where we found these features — were conducted by adherents of dark matter-free theories,” said co-author Jorge Moreno, associate professor of physics and astronomy at Pomona College. “Despite their obvious presence, little-to-no analysis was performed on these features by that community. It took folks like us, scientists working with both regular and dark matter, to start the conversation.”

Moreno added that he expects debate within his research community to follow in the wake of the study, but that there may be room for common ground, as the team also found that such features only appear in their simulations when there is both dark matter and normal matter in the universe.

“As stars are born and die, they explode into supernovae, which can shape the centers of galaxies, naturally explaining the existence of these features,” said Moreno. “Simply put, the features we examined in observations require both the existence of dark matter and the incorporation of normal-matter physics.”

Now that the dark matter model of the universe appears to be the leading one, the next step, Mercado explained, is to see if it remains consistent across a dark matter universe.

“It would be interesting to see if we could use this same relationship to even distinguish between different dark matter models,” said Mercado. “Understanding how this relationship changes under distinct dark matter models could help us constrain the properties of dark matter itself.”

A cosmic glitch in gravity

by Robin Y. Wen, Lukas T. Hergt, Niayesh Afshordi, Douglas Scott in Journal of Cosmology and Astroparticle Physics

A group of researchers at the University of Waterloo and the University of British Columbia have discovered a potential “cosmic glitch” in the universe’s gravity, explaining its strange behaviour on a cosmic scale.

For the last 100 years, physicists have relied upon Albert Einstein’s theory of “general relativity” to explain how gravity works throughout the universe. General relativity, proven accurate by countless tests and observations, suggests that gravity impacts not simply three physical dimensions but also a fourth dimension: time.

“This model of gravity has been essential for everything from theorizing the Big Bang to photographing black holes,” said Robin Wen, the lead author on the project and a recent Waterloo Mathematical Physics graduate.
“But when we try to understand gravity on a cosmic scale, at the scale of galaxy clusters and beyond, we encounter apparent inconsistencies with the predictions of general relativity. It’s almost as if gravity itself stops perfectly matching Einstein’s theory. We are calling this inconsistency a ‘cosmic glitch’: gravity becomes around one per cent weaker when dealing with distances in the billions of light years. “

For more than twenty years, physicists and astronomers have been trying to create a mathematical model that explains the apparent inconsistencies of the theory of general relativity. Many of those efforts have taken place at Waterloo, which has a long history of cutting-edge gravitational research resulting from ongoing interdisciplinary collaboration between applied mathematicians and astrophysicists.

“Almost a century ago, astronomers discovered that our universe is expanding,” said Niayesh Afshordi, a professor of astrophysics at the University of Waterloo and researcher at the Perimeter Institute.
“The farther away galaxies are, the faster they are moving, to the point that they seem to be moving at nearly the speed of light, the maximum allowed by Einstein’s theory. Our finding suggests that, on those very scales, Einstein’s theory may also be insufficient.”

The research team’s new model of a “cosmic glitch” modifies and extends Einstein’s mathematical formulas in a way that resolves the inconsistency of some of the cosmological measurements without affecting existing successful uses of general relativity.

“Think of it as being like a footnote to Einstein’s theory,” Wen said. “Once you reach a cosmic scale, terms and conditions apply.”
“This new model might just be the first clue in a cosmic puzzle we are starting to solve across space and time,” Afshordi said.

Biogenic Sulfur Gases as Biosignatures on Temperate Sub-Neptune Waterworlds

by Shang-Min Tsai, Hamish Innes, Nicholas F. Wogan, Edward W. Schwieterman in The Astrophysical Journal Letters

Recent reports of NASA’s James Webb Space Telescope finding signs of life on a distant planet understandably sparked excitement. A new study challenges this finding, but also outlines how the telescope might verify the presence of the life-produced gas. The UC Riverside study may be a disappointment to extraterrestrial enthusiasts but does not rule out the near-future possibility of discovery.

In 2023 there were tantalizing reports of a biosignature gas in the atmosphere of planet K2–18b, which seemed to have several conditions that would make life possible. Many exoplanets, meaning planets orbiting other stars, are not easily comparable to Earth. Their temperatures, atmospheres, and climates make it hard to imagine Earth-type life on them. However, K2–18b is a bit different.

“This planet gets almost the same amount of solar radiation as Earth. And if atmosphere is removed as a factor, K2–18b has a temperature close to Earth’s, which is also an ideal situation in which to find life,” said UCR project scientist and paper author Shang-Min Tsai.

K2–18b’s atmosphere is mainly hydrogen, unlike our nitrogen-based atmosphere. But there was speculation that K2–18b has water oceans, like Earth. That makes K2–18b a potentially “Hycean” world, which means a combination of a hydrogen atmosphere and water oceans. Last year, a Cambridge team revealed methane and carbon dioxide in the atmosphere of K2–18b using JWST — other elements that could point to signs of life.

The average volume mixing ratios (VMRs) as a function of sulfur biological flux (Sorg). We adopt the stellar spectrum of GJ 436 as an analogous star to K2–18 for our nominal Hycean K2–18 b model (top). Additionally, we scaled the solar flux to match an equivalent flux (bottom).

“What was icing on the cake, in terms of the search for life, is that last year these researchers reported a tentative detection of dimethyl sulfide, or DMS, in the atmosphere of that planet, which is produced by ocean phytoplankton on Earth,” Tsai said. DMS is the main source of airborne sulfur on our planet and may play a role in cloud formation.

Because the telescope data were inconclusive, the UCR researchers wanted to understand whether enough DMS could accumulate to detectable levels on K2–18b, which is about 120 light years away from Earth. As with any planet that far away, obtaining physical samples of atmospheric chemicals is impossible.

“The DMS signal from the Webb telescope was not very strong and only showed up in certain ways when analyzing the data,” Tsai said. “We wanted to know if we could be sure of what seemed like a hint about DMS.”

Based on computer models that account for the physics and chemistry of DMS, as well as the hydrogen-based atmosphere, the researchers found that it is unlikely the data show the presence of DMS. “The signal strongly overlaps with methane, and we think that picking out DMS from methane is beyond this instrument’s capability,” Tsai said. However, the researchers believe it is possible for DMS to accumulate to detectable levels. For that to happen, plankton or some other life form would have to produce 20 times more DMS than is present on Earth.

Detecting life on exoplanets is a daunting task, given their distance from Earth. To find DMS, the Webb telescope would need to use an instrument better able to detect infrared wavelengths in the atmosphere than the one used last year. Fortunately, the telescope will use such an instrument later this year, revealing definitively whether DMS exists on K2–18b.

“The best biosignatures on an exoplanet may differ significantly from those we find most abundant on Earth today. On a planet with a hydrogen-rich atmosphere, we may be more likely to find DMS made by life instead of oxygen made by plants and bacteria as on Earth,” said UCR astrobiologist Eddie Schwieterman, a senior author of the study.

Given the complexities of searching far-flung planets for signs of life, some wonder about the researchers continued motivations.

“Why do we keep exploring the cosmos for signs of life? Imagine you’re camping in Joshua Tree at night, and you hear something. Your instinct is to shine a light to see what’s out there. That’s what we’re doing too, in a way,” Tsai said.

Identification of the weak-to-strong transition in Alfvénic turbulence from space plasma

by Siqi Zhao, Huirong Yan, Terry Z. Liu, Ka Ho Yuen, Huizi Wang in Nature Astronomy

Astrophysicists from the University of Potsdam have made a significant step toward solving the last puzzle in magnetohydrodynamic turbulence theory by observing the weak to strong transition in the space plasma turbulence surrounding Earth with newly developed multi-spacecraft analysis methods.

Turbulence is ubiquitous in nature. It exists everywhere, from our daily lives to the distant universe, while being labelled as “the last great unsolved problem of classical physics” by Richard Feynman. Prof. Dr. Huirong Yan and her group from the Institute of Physics and Astronomy at the University of Potsdam and DESY have now discovered a long-predicted phenomenon: the weak-to-strong transition in small amplitude space plasma turbulence. The discovery was made by analyzing data from ESA’s Cluster mission — a constellation of four spacecraft flying in formation around Earth and investigating how the Sun and the Earth interact.

The weak-to-strong transition in Alfvénic turbulence is the most critical, yet observationally unconfirmed, prediction of magnetohydrodynamic (MHD) turbulence theory in the last three decades. It is exceptionally difficult because the three-dimensional sampling of turbulence fluctuations was not available yet. Therefore, the research team developed new multi-spacecraft analysis methods to obtain three-dimensional information on velocity and magnetic field fluctuations, allowing direct comparisons between observations and theory.

Perpendicular wavenumber dependence of the compensated spectra, parallel wavenumber and nonlinearity parameter.

“The observational confirmation of the weak-to-strong transition solves the last puzzle in MHD turbulence theory: It proves that the turbulence self-organizes from linear 2D wave-like fluctuations to strong 3D turbulence during the energy cascade (i.e., energy transfer across scales) with increasing nonlinearity, regardless of the initial level of disturbances, highlighting the universality of strong MHD turbulence,” says Huirong Yan, professor for plasma astrophysics at the University of Potsdam and leading scientist at DESY.

As the result, those findings substantially deepen our knowledge of ubiquitous turbulence, and their implications extend beyond the study of turbulence itself to particle transport and acceleration, magnetic reconnection, star formation, and all other relevant physical processes from our Earth to remote universe.

JWST observations of the Horsehead photon-dominated region I. First results from multi-band near- and mid-infrared imaging

by A. Abergel, K. Misselt, K.D. Gordon, A. Noriega-Crespo, P. Guillard, D. Van De Putte, A.N. Witt, N. Ysard, M. Baes, H. Beuther, P. Bouchet, B.R. Brandl, M. Elyajouri, O. Kannavou, S. Kendrew, P. Klassen, B. Trahin in arXiv

NASA’s James Webb Space Telescope has captured the sharpest infrared images to date of a zoomed-in portion of one of the most distinctive objects in our skies, the Horsehead Nebula. These observations show the top of the “horse’s mane” or edge of this iconic nebula in a whole new light, capturing the region’s complexity with unprecedented spatial resolution.

Webb’s new images show part of the sky in the constellation Orion (The Hunter), in the western side of a dense region known as the Orion B molecular cloud. Rising from turbulent waves of dust and gas is the Horsehead Nebula, otherwise known as Barnard 33, which resides roughly 1,300 light-years away.

The nebula formed from a collapsing interstellar cloud of material, and glows because it is illuminated by a nearby hot star. The gas clouds surrounding the Horsehead have already dissipated, but the jutting pillar is made of thick clumps of material and therefore is harder to erode. Astronomers estimate that the Horsehead has about five million years left before it too disintegrates. Webb’s new view focuses on the illuminated edge of the top of the nebula’s distinctive dust and gas structure.

This image of the Horsehead Nebula from NASA’s James Webb Space Telescope focuses on a portion of the horse’s “mane” that is about 0.8 light-years in width. It was taken with Webb’s NIRCam (Near-infrared Camera).

The Horsehead Nebula is a well-known photodissociation region, or PDR. In such a region, ultraviolet (UV) light from young, massive stars creates a mostly neutral, warm area of gas and dust between the fully ionized gas surrounding the massive stars and the clouds in which they are born. This UV radiation strongly influences the chemistry of these regions and acts as a significant source of heat.

These regions occur where interstellar gas is dense enough to remain mostly neutral, but not dense enough to prevent the penetration of UV light from massive stars. The light emitted from such PDRs provides a unique tool to study the physical and chemical processes that drive the evolution of interstellar matter in our galaxy, and throughout the universe from the early era of vigorous star formation to the present day.

Due to its proximity and its nearly edge-on geometry, the Horsehead Nebula is an ideal target for astronomers to study the physical structures of PDRs and the molecular evolution of the gas and dust within their respective environments, and the transition regions between them. It is considered one of the best regions in the sky to study how radiation interacts with interstellar matter.

Thanks to Webb’s MIRI and NIRCam instruments, an international team of astronomers has revealed for the first time the small-scale structures of the illuminated edge of the Horsehead. As UV light evaporates the dust cloud, dust particles are swept out away from the cloud, carried with the heated gas. Webb has detected a network of thin features tracing this movement. The observations have also allowed astronomers to investigate how the dust blocks and emits light, and to better understand the multidimensional shape of the nebula.

Next, astronomers intend to study the spectroscopic data that has been obtained to gain insights into the evolution of the physical and chemical properties of the material observed across the nebula.

A magnetar giant flare in the nearby starburst galaxy M82

by Mereghetti, S., Rigoselli, M., Salvaterra, R. et al in Nature

While ESA’s satellite INTEGRAL was observing the sky, it spotted a burst of gamma-rays — high-energy photons — coming from the nearby galaxy M82. Only a few hours later, ESA’s XMM-Newton X-ray space telescope searched for an afterglow from the explosion but found none. An international team, including researchers from the University of Geneva (UNIGE), realised that the burst must have been an extra-galactic flare from a magnetar, a young neutron star with an exceptionally strong magnetic field.

On 15 November 2023, ESA’s satellite INTEGRAL spotted a sudden explosion from a rare object. For only a tenth of a second, a short burst of energetic gamma-rays appeared in the sky. “The satellite data were received in the INTEGRAL Science Data Centre (ISDC), based on the Ecogia site of the UNIGE Astronomy Department, from where a gamma-ray burst alert was sent out to astronomers worldwide, only 13 seconds after its detection,” explains Carlo Ferrigno, senior research associate in the Astronomy Department at UNIGE Faculty of Science, PI of the ISDC and co-author of the publication.

The IBAS (Integral Burst Alert System) software gave an automatic localisation coinciding with the galaxy M82, 12 million light-years away. This alert system was developed and is operated by scientists and engineers from the UNIGE in collaboration with international colleagues.

“We immediately realised that this was a special alert. Gamma-ray bursts come from far-away and anywhere in the sky, but this burst came from a bright nearby galaxy,” explains Sandro Mereghetti of the National Institute for Astrophysics (INAF-IASF) in Milan, Italy, lead author of the publication and contributor of IBAS. The team immediately requested ESA’s XMM-Newton space telescope to perform a follow-up observation of the burst’s location as soon as possible. If this had been a short gamma-ray burst, caused by two colliding neutron stars, the collision would have created gravitational waves and have an afterglow in X-rays and visible light.

However, XMM-Newton’s observations only showed the hot gas and stars in the galaxy. Using ground-based optical telescopes, including the Italian Telescopio Nazionale Galileo and the French Observatoire de Haute-Provence, they also looked for a signal in visible light, starting only a few hours after the explosion, but again did not find anything. With no signal in X-rays and visible light, and no gravitational waves measured by detectors on Earth (LIGO/VIRGO/KAGRA), the most certain explanation is that the signal came from a magnetar.

“When stars more massive than eight times the Sun die, they explode in a supernova that leaves a black hole or neutron star behind. Neutron stars are very compact stellar remnants with more than the mass of the Sun packed into a sphere with the size of the Canton of Geneva. They rotate quickly and have strong magnetic fields.” explains Volodymyr Savchenko, senior research associate in the Astronomy Department at UNIGE Faculty of Science, and co-author of the publication. Some young neutron stars have extra strong magnetic fields, more than 10,000 times that of typical neutron stars. These are called magnetars. They emit energy away in flares, and occasionally these flares are gigantic.

However, in the past 50 years of gamma-ray observations, only three giant flares have been identified as coming from magnetars in our galaxy. These outbursts are very strong: one that was detected in December 2004, came from 30,000 light-years from us but was still powerful enough to affect the upper layers of Earth’s atmosphere, like the Solar flares, coming from much closer to us, do.

The flare detected by INTEGRAL is the first firm confirmation of a magnetar flare outside of the Milky Way. M82 is a bright galaxy where star formation takes place. In these regions, massive stars are born, live short turbulent lives and leave behind a neutron star. “The discovery of a magnetar in this region confirms that magnetars are likely young neutron stars,” adds Volodymyr Savchenko. The search for more magnetars will continue in other extra-galactic star-forming regions, to?understand these extraordinary astronomical objects. If astronomers can find many more, they can start to understand how often these flares happen and how neutron stars lose energy in the process.

Outbursts of such short duration can only be captured serendipitously when an observatory is already pointing in the right direction. This makes INTEGRAL with its large field of view, more than 3000 times greater than the sky area covered by the Moon, so important for these detections.

Carlo Ferrigno explains: “Our automatic data processing system is highly reliable and enables us to alert the community immediately.” When unexpected observations like this are picked up, INTEGRAL and XMM-Newton can be flexible in their schedules, which is essential in time-crucial discoveries. In this case, had the observations been performed even just a day later, there would not have been such strong proof that this was indeed a magnetar and not a gamma-ray burst.

Nonmagnetic framboid and associated iron nanoparticles with a space-weathered feature from asteroid Ryugu

by Yuki Kimura, Takeharu Kato, Satoshi Anada, Ryuji Yoshida, et al in Nature Communications

Samples reveal evidence of changes experienced by the surface of asteroid Ryugu, some probably due to micrometeoroid bombardment.

Analyzing samples retrieved from the asteroid Ryugu by the Japanese Space Agency’s Hayabusa2 spacecraft has revealed new insights into the magnetic and physical bombardment environment of interplanetary space. The results of the study is carried out by Professor Yuki Kimura at Hokkaido University and co-workers at 13 other institutions in Japan. The investigations used electron waves penetrating the samples to reveal details of their structure and magnetic and electric properties, a technique called electron holography.

Hayabusa2 reached asteroid Ryugu on 27 June 2018, collected samples during two delicate touchdowns, and then returned the jettisoned samples to Earth in December 2020. The spacecraft is now continuing its journey through space, with plans for it to observe two other asteroids in 2029 and 2031.

Particle A0064–FO007–I of asteroid Ryugu.

One advantage of collecting samples directly from an asteroid is that it allows researchers to examine long-term effects of its exposure to the environment of space. The ‘solar wind’ of high energy particles from the sun and bombardment by micrometeoroids cause changes known as space-weathering. It is impossible to study these changes precisely using most of the meteorite samples that land naturally on Earth, partly due to their origin from the internal parts of an asteroid, and also due to the effects of their fiery descent through the atmosphere.

“The signatures of space weathering we have detected directly will give us a better understanding of some of the phenomena occurring in the Solar System,” says Kimura. He explains that the strength of the magnetic field in the early solar system decreased as planets formed, and measuring the remnant magnetization on asteroids can reveal information about the magnetic field in the very early stages of the solar system.

Kimura adds, “In future work, our results could also help to reveal the relative ages of surfaces on airless bodies and assist in the accurate interpretation of remote sensing data obtained from these bodies.”

One particularly interesting finding was that small mineral grains called framboids, composed of magnetite, a form of iron oxide, had completely lost their normal magnetic properties. The researchers suggest this was due to collision with high velocity micrometeoroids between 2 and 20 micrometers in diameter. The framboids were surrounded by thousands of metallic iron nanoparticles. Future studies of these nanoparticles will hopefully reveal insights into the magnetic field that the asteroid has experienced over long periods of time.

“Although our study is primarily for fundamental scientific interest and understanding, it could also help estimate the degree of degradation likely to be caused by space dust impacting robotic or manned spacecraft at high velocity,” Kimura concludes.