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Identifying and delineating cell structures in microscopy images is crucial for understanding the complex processes of life. This task is called 'segmentation' and it enables a range of applications, such as analyzing the reaction of cells to drug treatments, or comparing cell structures in different genotypes. It was already possible to carry out automatic segmentation of those biological structures but the dedicated methods only worked in specific conditions and adapting them to new conditions was costly. An international research team has now developed a method by retraining the existing AI-based software Segment Anything on over 17,000 microscopy images with over 2 million structures annotated by hand.

Identifying and delineating cell structures in microscopy images is crucial for understanding the complex processes of life. This task is called 'segmentation' and it enables a range of applications, such as analyzing the reaction of cells to drug treatments, or comparing cell structures in different genotypes. It was already possible to carry out automatic segmentation of those biological structures but the dedicated methods only worked in specific conditions and adapting them to new conditions was costly. An international research team has now developed a method by retraining the existing AI-based software Segment Anything on over 17,000 microscopy images with over 2 million structures annotated by hand.

Individuals in industrialised societies seem to sleep for longer than people in non-industrialised ones, but their circadian rhythms are more out of sync

People in industrialised societies seem to sleep for longer than those in non-industrialised ones, but their circadian rhythms are more out of sync

Well that’s ruined all my lectures! I’ve spent years talking about space and a go to fact is the red colour of Mars. It’s been long believed that it was caused by the same chemical process that creates rust on Earth, a new paper suggests this is not the case! The team of researchers simulated conditions of Mars in a lab and now think a chemical called ferrihydrite, an iron oxide that contains water. It now looks like the planet’s characteristic red colour is due to a time when Mars was covered in water! 

Mars, often called the Red Planet is the fourth planet from the Sun. With a thin atmosphere composed mostly of carbon dioxide, Mars features a stark landscape of vast plains, huge volcanoes including Olympus Mons (the largest in our solar system), and deep canyons like Valles Marineris. Its surface has evidence of ancient rivers and lakes, suggesting Mars once had conditions that could have been suitable for microbial life. Its extreme temperature changes and frequent global dust storms are typical of this harsh world. 

Mars seen before, left, and during, right, a global dust storm in 2001. Credit: NASA/JPL/MSSS

The distinctive red colour goes back centuries; the ancient Egyptians called Mars ‘Her Desher’ which translates to ‘the Red One’, the Romans named it after the God of war and the Chinese called it ‘the fire star.’ Even Babylonian records that go back to 2000 BC noted its red colour. In 1610, when Galileo first observed Mars through a telescope, he confirmed its planetary nature but also noted a more red/brown hue. This was largely due to the poor quality optics of the day and it wasn’t until optics improved that its red colour was observed in all its glory.

A bust of Galileo at the Galileo Museum in Florence, Italy. The museum is displaying recovered parts of his body. Credit Kathryn Cook for The New York Times

A team of researchers led by Dr Adomas Valantinas from Brown University in USA have published a paper in Nature Communications that has analysed the red colouration of Mars and challenge the common view that it’s a rust like material that is responsible. They used data from a number of different Mars missions from NASA’s Reconnaissance Orbiter to ESA’s Mars Express and ExoMars (which has the Colour and Stereo Surface Imaging System onboard.) The data from the orbiters was supported by data from various rovers too and further supplemented by analysis of artificial Mars-like materials in a laboratory.

An artist’s illustration of the Mars Express Orbiter above Mars. Its MARSIS instrument has been updated so it can study the moon Phobos. Image Credit: Spacecraft: ESA/ATG medialab; Mars: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

The analysis, which included experiments and measurements at the University of Grenoble, Brown University and the University of Winnipeg revealed the presence of Ferrihydrite. Not only was it present in the Martian dust, it seemed to be widespread across the Martian landscape. Ferriydrite is an oxyhydroxide mineral (one that contains oxygen, hydrogen and at least one metal.)

The widespread discovery of ferrihydrite on in Martian dust helps us to understand more about the geological history of Mars and its potential habitability. The existence of the ferrihydrite tells us that there were once cooler, wet conditions on Mars since that is a neccessity for the formation of the mineral. It’s an exciting discovery because its one more reason to believe that Mars was once a hospitable world. 

The team are keen to learn more and are now waiting for Martian samples to study directly and for that, they are waiting for the Perseverance rover. It has been systematically collecting core samples of Martian soil from the Jezero Crater and storing them in titanium tubes ready for transport home. Once the team has these, they will be able to check whether their theory about ferrihydrite is correct.

Source : Why Mars could be red

The post A New Explanation for Why Mars is Red appeared first on Universe Today.

According to Darwin, life on Earth may have first appeared in warm little ponds. This simple idea is also a cornerstone in our search for the origin of life. The ponds were rich in important chemicals, and when lightning struck, somehow, it all got going.

If the idea is correct, the same thing may have happened on Mars. If it did, and if fossilized evidence of microbes on the planet exists, a new laser could find it.

We may never know exactly how life started. It appeared to start about 4 billion years ago on Earth, confined to water for about 3 billion, until our planet developed a UV-blocking ozone layer.

If life ever appeared on Mars, it also likely occurred billions of years ago when the planet was warm and wet. There’s a strong possibility that it was also confined to water for a long time. If it did, then ancient sediments could hold fossilized evidence of microbes.

NASA’s Perseverance rover landed in Jezero Crater, an ancient paleolake with deep sediments, in an attempt to detect evidence of ancient life. Jezero also contains an ancient river delta, an excellent place for sediments to collect and potentially preserve microbial evidence.

Perseverance carries a laser as part of its Supercam instrument, an improved version of MSL Curiosity’s Chemcam instrument and laser. Supercam analyzes rocks and soils and searches for organic compounds that are biosignatures of ancient microbial life.

Now, scientists are working on a new laser that could detect microbial fossils on Mars. The device will examine gypsum deposits for signs of these fossils. The device has already been tested in Mars-analogue gypsum deposits in Algeria.

The method is explained in new research published in Frontiers in Astronomy and Space Sciences. Its title is “The search for ancient life on Mars using morphological and mass spectrometric analysis: an analog study in detecting microfossils in Messinian gypsum.” The lead author is Youcef Sellam, a PhD student at the Physics Institute at the University of Bern.

“Our findings provide a methodological framework for detecting biosignatures in Martian sulfate minerals, potentially guiding future Mars exploration missions,” said Sellam. “Our laser ablation ionization mass spectrometer, a spaceflight-prototype instrument, can effectively detect biosignatures in sulfate minerals. This technology could be integrated into future Mars rovers or landers for in-situ analysis.”

Sellam is referring to sulphate minerals, including gypsum, left behind when bodies of water dry up. The minerals precipitate out and collect as deposits, as has happened repeatedly in the Mediterranean Sea during the Messinian salinity crisis.

“The Messinian Salinity Crisis occurred when the Mediterranean Sea was cut off from the Atlantic Ocean,” said Sellam. “This led to rapid evaporation, causing the sea to become hypersaline and depositing thick layers of evaporites, including gypsum. These deposits provide an excellent terrestrial analog for Martian sulfate deposits.”

We know something similar happened on Mars because gypsum deposits are plentiful. Since these deposits form rapidly, there’s a chance for fossils to be preserved before they can decompose.

“Gypsum has been widely detected on the Martian surface and is known for its exceptional fossilization potential,” explained Sellam. “It forms rapidly, trapping microorganisms before decomposition occurs, and preserves biological structures and chemical biosignatures.”

Gypsum deposits on Earth have been extensively studied for evidence of microbes.

These images, taken from separate research into gypsum deposits on Earth, show different types of microbial colonization in gypsum deposits. Panels B and C, for example, show zones rich in algal cells. More info here. Image Credit: Jehlicka et al. 2025.

“Prokaryotic communities are often found dwelling within modern evaporites, such as gypsum, forming in sabkhas, lacustrine, and marine terrestrial sediments,” the authors explain in their paper. “They mainly participate in carbon, iron, sulphur, and phosphate biogeochemical cycles, extracting water and using various survival strategies to avoid ecological stresses. Consequently, investigating these fossil filaments may enhance our comprehension of the cryptic conditions that led to the formation of the Primary Lower Gypsum unit during the Messinian Salinity Crisis, the biosignature preservation potential of gypsum, and the possible preservation of such fossils in ancient, hydrated sulphate deposits on Mars.”

Detecting evidence in Earth’s gypsum deposits is relatively simple. However, doing it on Mars is rife with challenges. Since scientists already know that Mediterranean gypsum deposits hold evidence of life, Sellam went to test the method there.

Sellam and his co-researchers tested their method at the Sidi Boutbal (SB) quarry in the Lower Chelif basin in Algeria. “The Chelif Basin is one of the largest Messinian peripheral sub-basins, characterized by an elongated and ENE–WSW oriented structure spanning over 260 km in length and 35 km in width,” the authors explain in their paper. The quarry contains gypsum deposits that are tens of meters thick.

These figures from the research show gypsum deposits in the Mediterranean, including the Sidi Boutbal quarry in Algeria, where the researchers tested their method. The black stars in C, D, and E show the sampled gypsum unit. Image Credit: Sellam et al. 2025.

The researchers used several methods in their work, including optical microscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy, and spatially resolved laser ablation mass spectrometry (LIMS). These aren’t new technologies, but combining them into an instrument that can be carried by a rover is new.

In their tests in Algeria, the researchers used a miniature laser-powered mass spectrometer, which can analyze the chemical composition of a sample in detail as fine as a micrometre. They also sampled gypsum and analyzed it using the mass spectrometer and an optical microscope. Many natural rock formations can mimic microbial fossils, so they followed criteria to distinguish between potential microbial fossils and natural rock formations. Microbial fossils display morphology which is irregular, sinuous, and potentially hollow.

In their paper, the authors report finding “a densely interwoven network of brownish, sinuous, and curved fossil filaments of various sizes.”

A is an optical microscope image of permineralized filamentous microfossils, and G is a scanning electron microscope of the same microfossils. Image Credit: Sellam et al. 2025.

Their method also detects the presence of chemical elements necessary for life, carbonaceous material, and minerals like clay or dolomite, which can be influenced by the presence of bacteria. “The inner layer of the filament is morphologically and compositionally distinct from the gypsum, mainly composed of Ca, S, O, and traces of Si,” the authors write.

This is a Scanning Electron Microscope and Energy Dispersive X-ray (SEM-EDX) spectrum of the same area. Red shows the predominant mineral, blue shows clay minerals, and yellow shows the inner layer of the fossil filaments. Image Credit: Sellam et al. 2025.

The authors found not only fossil filaments, but also dolomite, clay minerals, and pyrite surrounding the gypsum they were embedded in. This is important because their presence signals the presence of organic life. Prokaryotes supply elements that clays need to form and also help dolomite form, which often forms in the presence of gypsum. The only way that dolomite can form without life present is under high pressures and temperatures. To scientists’ knowledge, those conditions weren’t present on early Mars.

This is interesting progress, but there’s still lots of work to do.

It starts with identifying clay and dolomite in Martian gypsum. Along with other biosignatures, this indicates that fossilized life is there. If the system can identify other chemical minerals, that would help, too. Ultimately, finding organically formed filaments at the same time would be solid evidence that the planet once supported life.

“While our findings strongly support the biogenicity of the fossil filament in gypsum, distinguishing true biosignatures from abiotic mineral formations remains a challenge,” cautioned Sellam. “An additional independent detection method would improve the confidence in life detection. Additionally, Mars has unique environmental conditions, which could affect biosignature preservation over geological periods. Further studies are needed.”

If this method proves to be reliable, it’ll have to wait a while before being implemented.

The ESA’s Rosalind Franklin rover will launch to Mars in 2028. It will look for subsurface chemical and morphological evidence of life. Its instruments have already been chosen. Other nations and agencies have missions to Mars in the planning and proposal stages, but none of them are full-featured rovers like Curiosity and Perseverance.

However, another rover mission to Mars in the future is almost a certainty. Maybe this technology will be ready to go by then.

“Although the Messinian Salinity Crisis, during which the Primary Lower Gypsum formed, remains only partially understood, future astrobiological investigations on Mars should consider hydrated sulphate deposits as promising indicators of ancient Martian environmental conditions. This contribution underscores that hydrated sulphates serve as archives of biological history on Earth and potentially on Mars, should evidence of past life be found,” the authors conclude.

• Press Release: Laser-powered device tested on Earth could help us detect microbial fossils on Mars
• Published Research: The search for ancient life on Mars using morphological and mass spectrometric analysis: an analog study in detecting microfossils in Messinian gypsum

The post This Laser Could Find Fossil Microbes on Mars appeared first on Universe Today.

This article was mentioned in a comment by reader Ted Gold, but I thought I would highlight it just to show that when the rubber meets the road, people recognize that, yes, there are just two sexes. This is from the NYT on Feb. 25th.

Click headline to read, or find the article archived here.

An excerpt:

Women outlive men, by something of a long shot: In the United States, women have a life expectancy of about 80, compared to around 75 for men.

This holds true regardless of where women live, how much money they make and many other factors. It’s even true for most other mammals.

“It’s a very robust phenomenon all over the world, totally conserved in sickness, during famines, during epidemics, even during times of starvation,” said Dr. Dena Dubal, a professor of neurology at the University of California, San Francisco.

But if there are more than two sexes, why do articles like this one always accept that there are two, and, in this case, put people in one of the two classes to compare their longevity?  Why are they leaving out all those other sexes that, according to people like Agustín Fuentes and Steve Novella, actually exist? (They are not supposed to be rare, either!)

The article, which by the way is worth reading, though it does not mention evolution (another possible reason), does not refer to members of any other sex. Why not?

You know the answer: there are almost no people who do not fit the gametic definition of male or female, and those people are not members of other sexes. The failure of some Democrats to sign onto this recognition of the obvious is one reason why my party did poorly in the last election.

And yet so-called progressive Democrats and liberals are simply doubling down, as we will see tomorrow when I give a juicy example of resistance to the sex binary from an actual scientist.

The habitable zone of a planetary system is based on a simple idea: if a planet is too close to its star then conditions are too hot for life, and if a planet is too distant then things are too cold. It’s broadly based on the estimated temperature/distance range for liquid water to exist on a planet’s surface, since life as we know it needs liquid water to exist. The problem with this definition is that it’s too crude to be very useful. For example, both Venus and Mars are at the inner and outer edges of the Sun’s habitable zone, but neither are really habitable. But now that we have observed hundreds of planetary systems, we can start to pin down the zone more accurately. One way to do this is to look at sulfur chemistry.

A new paper in Science Advances looks at how sulfur chemistry can better define the inner border of a star’s habitable zone. The authors note that the key is whether a planet can maintain a surface ocean. Many inner planets are warm enough to have liquid oceans early on but lose those oceans over time. Venus is a good example of this. Early Venus was likely very Earth-like, but the lack of a strong magnetic field and water-rich volcanic activity meant Venus’s early oceans boiled away.

Even from light-years away, the difference between Venus and Earth is striking. If alien astronomers were to observe the atmospheres of both, they would see that Earth has a mix of nitrogen and oxygen, while Venus has a mostly carbon dioxide atmosphere rich in sulfur dioxide. From this, they would know that Earth has oceans while Venus does not. Both planets have plenty of sulfur, but Earth’s oceans prevent large amounts of sulfur dioxide from forming. It takes dry surface chemistry to create sulfur dioxide.

The authors show how the presence of atmospheric sulfur is a marker for an oceanless planet. For sunlike stars, this could be used to narrow the habitable zone and select better candidates for alien life. If an inner planet has a sulfur-rich atmosphere, there’s no need to look further. There is, however, a catch.

While dry, warm planets would tend to generate plenty of sulfur compounds, ultraviolet light tends to break these molecules up. So, the team demonstrates, while the presence of atmospheric sulfur proves a planet is dry, the opposite is not always true. A dry planet orbiting a high-UV star would also lack sulfur compounds. To demonstrate this, the team looked at the red dwarf system TRAPPIST-1, which has at least three potentially habitable planets. They found that the UV levels for these worlds are too high to use the sulfur test. This is a real bummer, since red dwarf planets are the most common home for potentially habitable worlds, and most of those planets are bathed in much more UV than Earth since they orbit their star so closely.

So this study shows that sulfur chemistry is a useful tool for finding life, though not as useful as we’d like. It will take more chemical identifiers to narrow down the habitable zones for red dwarfs.

Reference: Jordan, Sean, Oliver Shorttle, and Paul B. Rimmer. “Tracing the inner edge of the habitable zone with sulfur chemistry.” Science Advances 11.5 (2025): eadp8105.

The post Can We Develop a More Accurate Habitable Zone Using Sulfur? appeared first on Universe Today.

On Wednesday 26 February, a thermal imaging camera blasted off to the Moon as part of NASA's Lunar Trailblazer mission. This aims to map sources of water on the Moon to shed light on the lunar water cycle and to guide future robotic and human missions.

On Wednesday 26 February, a thermal imaging camera blasted off to the Moon as part of NASA's Lunar Trailblazer mission. This aims to map sources of water on the Moon to shed light on the lunar water cycle and to guide future robotic and human missions.

New observations of 2024 YR4 conducted with the European Southern Observatory's Very Large Telescope (ESO's VLT) and facilities around the world have all but ruled out an impact of the asteroid with our planet. The asteroid has been closely monitored in the past couple of months as its odds of impacting Earth in 2032 rose to around 3%, the highest impact probability ever reached for a sizable asteroid. After the latest observations, the odds of impact dropped to nearly zero.

A new study has revealed key factors limiting the efficiency of photoelectrochemical water splitting using a titanium dioxide photoanode for clean hydrogen production. Researchers combined intensity-modulated photocurrent spectroscopy with the distribution of relaxation times analysis to analyze charge carrier dynamics. They identified distinct behaviors related to light intensity and recombination at different applied potentials and discovered a previously unreported 'satellite peak,' offering new insights for improving material design and hydrogen production efficiency.

Traditional machine learning models for automatic information classification require retraining data for each task. Researchers have demonstrated that art data can be automatically classified with sufficient accuracy by using a large language model (LLM), without requiring additional training data.

Labor market policies shape firms' innovation dynamics. A new study shows for the first time that higher minimum wages for low-skill jobs drive firms to develop automation technologies. Rising wages for high-skill labor, in contrast, can hamper this effect.

Labor market policies shape firms' innovation dynamics. A new study shows for the first time that higher minimum wages for low-skill jobs drive firms to develop automation technologies. Rising wages for high-skill labor, in contrast, can hamper this effect.

A new study shows a water-rich mineral could explain the planet's color -- and hint at its wetter, more habitable past.

Using the James Webb Space Telescope, astronomers investigate the extreme weather patterns and atmospheric properties of exoplanet LTT 9779 b. New JWST observations with NIRISS reveal a dynamic atmosphere: powerful winds sweep around the planet, shaping mineral clouds as they condense into a bright, white arc on the slightly cooler western side of the dayside. As these clouds move eastward, they evaporate under the intense heat, leaving the eastern dayside with clear skies.

Astronomers have discovered that the Solar System traversed the Orion star-forming complex, a component of the Radcliffe Wave galactic structure, approximately 14 million years ago. This journey through a dense region of space could have compressed the heliosphere, the protective bubble surrounding our solar system, and increased the influx of interstellar dust, potentially influencing Earth's climate and leaving traces in geological records.

Silicon is the best-known semiconductor material. However, controlled nanostructuring drastically alters the material's properties. Using a specially developed etching apparatus, a team has now produced mesoporous silicon layers with countless tiny pores and investigated their electrical and thermal conductivity. For the first time, the researchers elucidated the electronic transport mechanism in this mesoporous silicon. The material has great potential for applications and could also be used to thermally insulate qubits for quantum computers.

Silicon is the best-known semiconductor material. However, controlled nanostructuring drastically alters the material's properties. Using a specially developed etching apparatus, a team has now produced mesoporous silicon layers with countless tiny pores and investigated their electrical and thermal conductivity. For the first time, the researchers elucidated the electronic transport mechanism in this mesoporous silicon. The material has great potential for applications and could also be used to thermally insulate qubits for quantum computers.