Category: 7. Science

A mini solar telescope strapped to the side of the International Space Station (ISS) has captured its first images, revealing subtle changes in our home star’s outer atmosphere that have never been seen before.

NASA’s Coronal Diagnostic Experiment (CODEX) is a small solar telescope attached to the outside of the ISS. It is a coronagraph, meaning that it blocks out the solar disk to allow the telescope to focus on the sun’s atmosphere, or corona, in unprecedented detail — mimicking the way the moon blocks the sun’s visible surface during a total solar eclipse on Earth. The occulting disk blocking out the sun’s light is around the size of a tennis ball and it is held in place by three metal arms at the end of a long metal tube, which also cast distinctive shadows in the resulting images.

The planet Venus is like Earth’s worst twin – roughly the same size but with a thick layer of acid clouds over a crushing, hellish atmosphere. Its clouds in particular have been a source of interest, but it is difficult to understand how they change long-term: most missions around the planet don’t last long. New observations might have finally filled that gap in knowledge, thanks to weather satellites orbiting our planet that caught a glimpse of Venus accidentally.

The Himawari-8 and -9 satellites, launched in 2014 and 2016, are Japanese meteorological satellites. They were designed to study global atmospheric phenomena, something that they do well thanks to a particular type of instrument: multispectral Advanced Himawari Imagers (AHIs). This device can – when the alignment is right – capture Venus just at the edge of Earth.

A team from the University of Tokyo, led by visiting researcher Gaku Nishiyama, realized that the instrument would be able to measure variation in the temperature on top of the Venusian clouds. They collected data from 2015 to 2025, providing crucial monitoring of the nearby rocky planet.  

“The atmosphere of Venus has been known to exhibit year-scale variations in reflectance and wind speed; however, no planetary mission has succeeded in continuous observation for longer than 10 years due to their mission lifetimes,” Nishiyama said in a statement. “Ground-based observations can also contribute to long-term monitoring, but their observations generally have limitations due to the Earth’s atmosphere and sunlight during the daytime.” 

The team was able to find 437 occurrences of the alignment in total, and they were able to show that temperatures did indeed change across the 10 years. Such methods will be very useful for continuous monitoring of Venus before future missions get there, though, while the European EnVision mission to Venus is still scheduled for the next decade, NASA’s two missions to Venus are in jeopardy following the Trump administration’s cuts.

“We believe this method will provide precious data for Venus science because there might not be any other spacecraft orbiting around Venus until the next planetary missions around 2030,” said Nishiyama.

It might not just be a tool for Venus either. The team believes that they can use accidental photobombs in weather satellites to study other worlds of the Solar System. The advantage of orbital observations is the lack of atmosphere, which affects what we can do from the ground.

“I think that our novel approach in this study successfully opened a new avenue for long-term and multiband monitoring of solar system bodies. This includes the moon and Mercury, which I also study at present. Their infrared spectra contain various information on physical and compositional properties of their surface, which are hints at how these rocky bodies have evolved until the present,” added Nishiyama.

The study is published in the journal Earth, Planets and Space.

HCl was detected in the Martian atmosphere by the NOMAD and ACS spectrometers aboard the ExoMars TGO. Photochemical models show that using gas-phase chemistry alone is insufficient to reproduce these data.

Recent work has developed a heterogeneous chemical network within a 1D photochemistry model, guided by the seasonal variability in HCl. The aim of this work is to show that incorporating heterogeneous chlorine chemistry into a global 3D model of Martian photochemistry with conventional gas-phase chemistry can reproduce spatial and temporal changes in hydrogen chloride on Mars. We incorporated this heterogeneous chlorine scheme into the MPCM to model chlorine photochemistry during MYs 34 and 35.

These two years provide contrasting dust scenarios, with MY 34 featuring a global dust storm. We also examined correlations in the model results between HCl and other key atmospheric quantities, as well as production and loss processes, to understand the impact of different factors driving changes in HCl.

We find that this 3D model of Martian is consistent with the changes in HCl observed by ACS in MY 34 and MY 35, including detections and 70% of non-detections. For the remaining 30%, model HCl is higher than the ACS detection limit due to biases associated with water vapour, dust, or water ice content at these locations.

As with previous 1D model calculations, we find that heterogeneous chemistry is required to describe the loss of HCl, resulting in a lifetime of a few sols that is consistent with the observed seasonal variation in HCl.

As a result of this proposed chemistry, modelled HCl is correlated with water vapour, airborne dust, and temperature, and anticorrelated with water ice. Our work shows that this chemical scheme enables the reproduction of aphelion detections in MY 35.

Benjamin Benne (1,2), Paul I. Palmer (1,2), Benjamin M. Taysum (3), Kevin S. Olsen (4,5), Franck Lefèvre (6) ((1) The University of Edinburgh, School of GeoSciences, UK, (2) Centre for Exoplanet Science, University of Edinburgh, UK, (3) DLR, Germany, (4) Department of Physics, University of Oxford, UK, (5) School of Physical Sciences, The Open University, UK, (6) LATMOS, France)

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Chemical Physics (physics.chem-ph)
Cite as: arXiv:2506.18757 [astro-ph.EP] (or arXiv:2506.18757v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2506.18757
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Related DOI:
https://doi.org/10.1051/0004-6361/202553872
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Submission history
From: Benjamin Benne
[v1] Mon, 23 Jun 2025 15:28:45 UTC (2,899 KB)
https://arxiv.org/abs/2506.18757
Astrobiology

Scientists are claiming a “cosmic chemistry breakthrough” following the discovery of a large “aromatic” molecule in deep space. The discovery suggests that these molecules could help seed planetary systems with carbon, supporting the development of molecules needed for life.

The molecule, called cyanocoronene, belongs to a class of carbon-based organic compounds called polycyclic aromatic hydrocarbons (PAHs), which are made up of multiple fused aromatic rings — structures in which electrons are shared across double-bonded carbon atoms, giving them unique chemical stability.

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In these polar waters, cold, fresh surface water overlays warmer, saltier waters from the deep. In the winter, as the surface cools and sea ice forms, the density difference between water layers weakens, allowing these layers to mix and heat to be transported upward, melting the sea ice from below and limiting its growth.

Since the early 1980s, the surface of the Southern Ocean had been freshening, and stratification – that density difference between the water layers – had been strengthening. This was trapping heat below and sustaining more sea ice coverage.

Now, new satellite technology, combined with information from floating robotic devices which travel up and down the water column, shows this trend has reversed; surface salinity is increasing, stratification is weakening, and sea ice has reached multiple record lows – with large openings of open ocean in the sea ice (polynyas) returning.

This is the first time scientists have been able to monitor these changes in the Southern Ocean in real time. 

Aditya Narayanan, a postdoctoral research fellow at the University of Southampton and co-author on the paper, said: “While scientists expected that human-driven climate change would eventually lead to Antarctic Sea ice decline, the timing and nature of this shift remained uncertain.

“Previous projections emphasised enhanced surface freshening and stronger ocean stratification, which could have supported sustained sea ice cover. Instead, a rapid reduction in sea ice – an important reflector of solar radiation – has occurred, potentially accelerating global warming.”

What this all means is that – according to Professor Alberto Naveira Garabato, co-author on the study and Regius Professor of Ocean Sciences at the University of Southampton – our current understanding “may be insufficient” to accurately predict future changes.

“It makes the need for continuous satellite and in-situ monitoring all the more pressing, so we can better understand the drivers of recent and future shifts in the ice-ocean system.”

The paper – ‘Rising surface salinity and declining sea ice: a new Southern Ocean state revealed by satellites is published in Proceedings of the National Academy of Sciences and is available online.

This project has been supported by the European Space Agency.

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The totality of bacteria, viruses and fungi that exist in and on a multicellular organism forms its natural microbiome. The interactions between the body and these microorganisms significantly influence both, the functions and health of the host organism. Researchers assume that the microbiome plays an important role in the defence against pathogens, among other things. The Collaborative Research Centre (CRC) 1182 “Origin and Function of Metaorganisms” at Kiel University has been investigating the highly complex interplay between host organisms and microorganisms for several years using various model organisms, including the nematode Caenorhabditis elegans.

In a recent study, researchers from the CRC 1182 have gained new insights into the molecular mechanisms within the microbiome which contribute to the defence against pathogens. In collaboration with scientists from the Max Planck Institute for Terrestrial Microbiology and the University of Edinburgh, they discovered that a protective bacterium of the genus Pseudomonas, which is found in the intestinal microbiome of C. elegans, produces sphingolipids. This result was surprising, as it was previously assumed that the production of sphingolipids was restricted to only a few bacterial phyla and the bacterial genus Pseudomonas was not known to be able to produce these specific molecules. The researchers discovered that Pseudomonas utilises an alternative metabolic pathway for sphingolipid production, which differs significantly from the known sphingolipid synthesis pathways in other bacteria. They were also able to show that the sphingolipids produced by Pseudomonas bacteria play an essential role in protecting the intestinal epithelium of the host from damage by the pathogen.

Responsible for sphingolipid production in Pseudomonas bacteria is a specific biosynthetic gene cluster that forms the enzymes for this novel metabolic pathway. Interestingly, similar gene clusters were also found in other host-associated gut bacteria, suggesting that the ability to produce sphingolipids may be more widespread than previously thought. This suggests that bacterial sphingolipids may play a central role in microbiome-mediated protection against infection – not only in C. elegans, but potentially also in other host organisms. The results of the interdisciplinary study, conducted under the leadership of PD Dr Katja Dierking (Evolutionary Ecology and Genetics research group at Kiel University), in collaboration with other research groups from Kiel and national and international cooperation partners, were recently published in the journal Nature Communications.

Bacteria use alternative pathway to produce protective sphingolipids

A few years ago, the Kiel research group had already published a study (Kissoyan et al. (2019), Current Biology) that showed that certain members of the C. elegans microbiota protect against pathogen infection.  “For one Pseudomonas species we knew that it can protect the worm from infections. However, we had not yet been able to identify the substances and mechanisms involved,” emphasises Dr Lena Peters, a scientist in the Evolutionary Ecology and Genetics research group.

In a broad-based collaboration of scientists both within the CRC 1182 – including Kiel professors Christoph Kaleta and Manuel Liebeke – and with external scientists, including Professor Helge Bode from the MPI for Terrestrial Microbiology in Marburg and Professor Dominic Campopiano from the University of Edinburgh in Scotland, the genetic and metabolic basis of the protection against infection mediated by the microbiome was analyzed. Using metabolic and transcriptional studies, single molecule analyses and mass spectrometry approaches, the researchers made a surprising discovery: they were able to prove that the protective bacteria of the genus Pseudomonas produce sphingolipids that influence the worm’s sphingolipid metabolism and thus support the host’s protection against pathogens.

“This finding is relatively new,” explains Peters, member of the CRC 1182, “normally, bacteria use the sphingolipid metabolism of host organisms to manipulate it in a targeted manner to promote infections. In our case, however, we observe the opposite – bacterial sphingolipids apparently actively support the protection of the host.” Sphingolipids are fat-like molecules that are typically found in eukaryotes, where they fulfil important structural and regulatory functions, but are rare in bacteria. In Pseudomonas, they are synthesised via a previously unknown, alternative metabolic pathway – not as a component of primary metabolism, as is usually the case, but as a so-called secondary metabolite.

The researchers discovered that this previously unknown metabolic pathway is based on a specific biosynthetic gene cluster, a so-called polyketide synthase. “With our experiments, we were able to confirm that the worms survived better in the presence of Pseudomonas fluorescens bacteria possessing this gene cluster when they were infected with the pathogen Bacillus thuringiensis,” emphasises Peters, first author of the study. After identifying the responsible genes, the scientists could confirm through further analyses that the gene cluster encodes the enzymes required for sphingolipid synthesis. “It is exciting to be authors on this important, breakthrough paper. We are pleased that our expertise in bacterial sphingolipid research has helped discover a new role in the worm microbiome for these enigmatic lipids,” says Prof. Campopiano.

“The protective mechanism against infections with B. thuringiensis apparently works indirectly. The lipids produced by Pseudomonas influence the worm’s sphingolipid metabolism, which presumably leads to an improved barrier function of the intestinal cells,” explains Peters. When the worm is infected with B. thuringiensis, the toxins of the pathogen create small pores in the cell membrane of the host, which makes it easier for the pathogens to penetrate. “We assume that the sphingolipid metabolism modified by P. fluorescens strengthens the stability and resistance of the cell membranes – and thus offers effective, indirect protection against pathogens,” Peters continues.

“Overall, the new research work expands our understanding of how microbial metabolites support host defence against pathogens,” says Dierking, independent group leader in the Evolutionary Ecology and Genetics research group. In the long term, the researchers of the CRC 1182, who are also active in Kiel University’s priority research area Kiel Life Science (KLS), hope that better knowledge of such fundamental mechanisms will also make it possible to influence disorders of the human gut microbiome which may result in better treatment options for a variety of associated diseases.

Reference: Peters L, Drechsler M, Herrera MA, et al. Polyketide synthase-derived sphingolipids mediate microbiota protection against a bacterial pathogen in C. elegans. Nat Commun. 2025;16(1):5151. doi: 10.1038/s41467-025-60234-1

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After nearly two decades in orbit, NASA’s Mars Reconnaissance Orbiter (MRO) is trying something new.

Engineers have taught the spacecraft how to roll – hard. This isn’t just a simple tilt. These are full-body rolls, sometimes nearly upside down.

The purpose is to see deeper beneath the surface of Mars and hunt for signs of water and ice.

Teaching Mars Orbiter to roll

The new technique comes from scientists at the Planetary Science Institute and NASA’s Jet Propulsion Laboratory.

Between 2023 and 2024, MRO performed three massive rotations – what the team calls “very large rolls” – to boost the performance of one of its key instruments.

“Not only can you teach an old spacecraft new tricks, you can open up entirely new regions of the subsurface to explore by doing so,” said Gareth Morgan of the Planetary Science Institute in Tucson, Arizona.

Advanced planning and careful balance

Mars Reconnaissance Orbiter was originally built to roll up to 30 degrees to aim its cameras and sensors at specific features on the Martian surface.

It’s a flexible platform, designed to twist and turn in space so scientists can target impact craters, landing zones, and more.

“We’re unique in that the entire spacecraft and its software are designed to let us roll all the time,” said Reid Thomas, MRO’s project manager at NASA’s Jet Propulsion Laboratory in Southern California.

But the bigger rolls – 120 degrees or more – are something else entirely. These require advanced planning and careful balance.

Mars Orbiter: Why every roll counts

MRO’s five main science instruments all have different needs. When one is pointed at Mars, others might lose their ideal view.

That means every maneuver is scheduled weeks in advance. Teams negotiate which instruments will be active and when.

An algorithm takes over from there, guiding the orbiter to roll and aim while keeping its solar panels locked on the Sun and its antenna aimed at Earth. For very large rolls, even those systems go dark temporarily.

“The very large rolls require a special analysis to make sure we’ll have enough power in our batteries to safely do the roll,” Thomas said.

Flipping for stronger radar returns

The massive rolls are especially helpful for SHARAD, the Shallow Radar instrument on board. It is designed to see about half a mile to 1.2 miles (0.8 – 1.9 kilometers) below the Martian surface.

SHARAD can also differentiate between ice, rock, and sand – a crucial capability for identifying water that future astronauts might one day use.

“The SHARAD instrument was designed for the near-subsurface, and there are select regions of Mars that are just out of reach for us,” said Morgan. “There is a lot to be gained by taking a closer look at those regions.”

Normally, SHARAD’s signals bounce off parts of the orbiter before hitting Mars, which muddies the data. But by flipping the spacecraft 120 degrees, SHARAD gets a clean line of sight. That single move boosts signal strength tenfold or more.

This improvement is big, but it comes with tradeoffs. During the maneuver, MRO can’t communicate with Earth or recharge its batteries. That limits the team to one or two very large rolls each year – for now.

Old instruments with new tricks

SHARAD isn’t the only instrument adjusting to new routines. The Mars Climate Sounder, a radiometer built at JPL, is also leaning into MRO’s roll capability. It tracks temperatures and atmospheric changes on Mars, revealing patterns in dust storms and cloud formations.

Originally, this instrument used a gimbal to adjust its view. But the gimbal started to fail in 2024. Now, the Climate Sounder depends on the orbiter’s roll maneuvering instead.

“Rolling used to restrict our science, but we’ve incorporated it into our routine planning, both for surface views and calibration,” said Mars Climate Sounder’s interim principal investigator, Armin Kleinboehl of JPL.

Mars Orbiter still delivers after 18 years

NASA’s Mars Reconnaissance Orbiter has been circling the Red Planet since 2006. It’s an aging but incredibly capable machine.

These new rolling maneuvers show that even after 18 years in space, it’s still finding new ways to contribute.

By shifting its body in bold new directions, MRO is helping us see what lies beneath the Martian dust – and just maybe, where water waits to be found.

Image Credit: NASA/JPL-Caltech

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The Earth’s atmosphere is now trapping far more heat than climate models predicted. This energy imbalance has doubled since 2005, from 0.6 to 1.3 watts per square meter, according to researchers from Australia, France and Sweden. The Conversation reports.

Scientists believe the acceleration is due to the accumulation of greenhouse gases and changes in cloud cover. In particular, the area of white reflective clouds has decreased, while darker ones have increased. This weakens the planet’s ability to reflect the sun’s heat back into space.

Most of the additional energy (up to 90%) is absorbed by the oceans, but there is also melting of glaciers and warming of land. This accumulation of heat has already raised the average temperature of the Earth by 1.3–1.5°C compared to the pre-industrial period.

The authors emphasize that real changes are happening faster than the models predict. If the trend continues, the world could face increased heat waves, droughts and storms. What is particularly worrying is that only models with high sensitivity to emissions come close to the recorded values – they predict more severe warming in the future.

An additional threat is a possible reduction in funding for satellite climate monitoring in the United States, a key tool that allows us to capture such changes at an early stage.

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Ecosystems aren’t just defined by what species exist, but by how much life they contain. While scientists understand species diversity and where marine life is most abundant today, we still lack a clear picture of how biomass, the total weight of living organisms, has changed over time.

Biomass reveals the real impact and energy flow of life in an ecosystem, like knowing not just the cast of a play, but who the lead actors are and how powerful their performances can be. It’s a vital clue to understanding an ecosystem’s true strength and health across deep time.

While scientists have long known that biodiversity has increased throughout Earth’s history, a new Stanford study adds a key piece: biomass, or the total amount of ocean life, has also mostly grown over the last 500 million years.

Despite some dips during mass extinction events, the overall trend is upward, just like biodiversity. This suggests a powerful link: as life became more diverse, it also became more abundant, filling the oceans with both variety and volume.

Scientists uncover massive, diverse ecosystem deep beneath Earth’s surface

Imagine if ancient seas left behind a diary, not in words, but in shells and skeletons. That’s exactly what the team is decoding. Researchers studied thousands of rock samples packed with the fossilized remains of marine organisms, shells, algae, and tiny protists. These fossils recorded the biomass of their time, that is, the total “living material” preserved across Earth’s history.

Why does it matter?

Biomass reveals how much life an ecosystem could support, and how much energy it moves around, making it a key sign of past ocean health.

Although it once seemed too complex to measure across deep time, researchers took on the challenge. They analyzed over 7,700 limestone samples spanning 540 million years, using a method called petrographic point-counting to examine the amount of fossilized shell material.

By combining decades of studies with new data, they created a clearer picture of how life in Earth’s oceans has ebbed and flowed through deep history.

Some sea life could face extinction over the next century

They found that in the Cambrian Period, fewer than 10% of rocks had shell material. As life diversified during the Ordovician, that percentage rose, evidence of the Cambrian Explosion.

Calcifying sponges were among the early biomass leaders but were soon overtaken by echinoderms (like early starfish) and marine arthropods (like trilobites and crab ancestors).

Over the past 230 million years, oceans saw dramatic rises and falls in life, recorded in the shell content of marine rocks. Shell material stayed above 20%, signaling healthy ocean life, until the Late Devonian extinction (~375–360 million years ago) caused a notable drop.

Then came the worst: the Great Dying (~250 million years ago), the Permian-Triassic extinction, when shell content plunged to just 3%, reflecting a massive collapse in marine life.

Even after major extinctions like the end-Triassic and the one that ended the dinosaurs, marine life bounced back. In today’s era, the Cenozoic, shell remains now make up over 40% of marine rocks, largely due to mollusks and corals thriving.

To be sure, this rise reflected real increases in ocean life, not just fewer shell-destroying predators or sampling bias, researchers ran thorough tests. They analyzed fossil samples across shallow and deep waters, various latitudes, and different ancient continental setups.

Animal poop helps ecosystems adapt to climate change, study

The result? The trend held strong across the board, showing that the growth in shell content truly reflects a long-term rise in ocean biomass.

As ocean organisms became more specialized, they got better at using energy and nutrients, boosting ecosystem productivity. This efficient recycling from phytoplankton to decomposers helped support more life, reflected in greater biomass.

But today, human impacts like pollution, overfishing, and climate change threaten that balance. Scientists warn we may be entering a sixth mass extinction, where shrinking biodiversity could reduce biomass, and future fossil records might carry the traces of this decline.

Jonathan Payne, Dorrell William Kirby Professor of Earth and Planetary Sciences, said, “Our findings show that overall biomass is linked to biodiversity and that losses in biodiversity may suppress productivity for geologically meaningful intervals, adding one more argument for why conserving biodiversity is essential for the health of humans and our planet.”

Journal Reference:

1. Pulkit Singh, Jordan Ferré, Bridget Thrasher, et al. Macroevolutionary coupling of marine biomass and biodiversity across the Phanerozoic. Current Biology. DOI: 10.1016/j.cub.2025.06.006