Despite continual habitability headlines, the debate over whether Mars ever had or currently has life still rages. At every new planetary conference, someone presents data that often for a few weeks at least appears to change the calculus of Martian astrobiology. But for well over two decades now, one of the biggest mysteries remains --- the origin of the putative methane detections made by the Tunable Laser Spectrometer (TLS) on NASA's Curiosity rover which has repeatedly reported several detections of methane.

This methane flap actually began with the European Space Agency’s Mars Express spacecraft which started orbital science operations in 2004. During Mars Express’ first year of observations and analysis, a small spectrometer on the spacecraft detected a very low-resolution spectral bump which indicated the tenuous infrared absorption of methane in the red planet’s atmosphere.

Yet the detections were at the limits of the instrument’s (the Planetary Fourier Spectrometer) sensitivity, ESA notes.

It's not that convincing, but at the very same time, two different independent research groups using ground-based telescopes were also claiming that they could see Mars methane through Earth's atmosphere, Kevin Olsen, a planetary scientist at the University of Oxford and a co-investigator of the ExoMars Trace Gas Orbiter's Atmospheric Chemistry suite instrument, told me in the U.K.

Habitability is the key.

The most important thing people care about is whether Mars has been or is habitable, and whether there's microbial life, and in the atmosphere the big thing is methane, which we don't see, says Olsen.

As for the ExoMars TGO?
The Trace Gas Orbiter primary objective is to definitively detect trace gasses such as compounds with sulfur, chlorine, and methane.

If methane is coming from a biosphere, then either living things are producing methane as they go about their daily life and use energy, says Olsen. Or maybe they're not living anymore, and there remains an ancient source of biologically created methane.

If methane is not coming from a biological source; then the most likely thing is active rock metamorphosis, he says.

This is where rock changes from one type into another, which would happen deep underground, at high pressure, with lots of heat, water and chemical energy. But after eight years of observations with TGO’s instruments working at nominal levels, the ESA team still has not found evidence for methane.

We have a thousand times better sensitivity than the Mars sample analysis suite on NASA’s Curiosity rover, but we do not see any sign of the absorption of methane in the Martian atmosphere, says Olsen.

Every time electricity flows through a wire, some of its energy is inevitably lost as heat because electrons collide with one another and with the material around them. But just how much can these collisions increase electrical resistance? A new study suggests there is a fundamental limit.

To investigate, researchers from the University of Toronto, L’École Normale Supérieure in Paris, and Lehigh University turned to an unusual stand-in for electrons: ultracold potassium atoms cooled to temperatures just above absolute zero.

By precisely controlling how often the atoms collided, they found that resistance increased only up to a certain point before leveling off. The discovery provides rare experimental evidence for a microscopic limit to resistivity and could improve scientists’ understanding of electron behavior in quantum materials.

“Electron-on-electron collisions are known to increase resistivity in some pure materials,” explains Professor Joseph Thywissen in the Department of Physics and the Center for Quantum Information and Quantum Control in the Faculty of Arts & Science at the University of Toronto, senior author of a study published in Physical Review Letters. “The energy produced by electrical resistance shows up as heat. Transmission lines, for instance, lose up to 8% of the generated electrical power. Resistivity is also interesting to study because it can be a signature of new physics in materials.”

The smallest centipedes have 30 legs, while the largest ever discovered had 382 👀
🐛 Despite the name, no centipede with exactly 100 legs has ever been found. Surprising science explains why!

The liver is one of the body’s hardest-working organs, carrying out hundreds of vital jobs, from filtering toxins and metabolizing medications to producing proteins essential for blood clotting. Yet when it fails, the only definitive treatment is often a transplant, a solution limited by a chronic shortage of donor organs.

MIT engineers have now developed injectable “mini livers” that, in mice, survived for at least two months while performing many of the functions of healthy liver tissue.

“We think of these as satellite livers. If we could deliver these cells into the body, while leaving the sick organ in place, that would provide booster function,” says Sangeeta Bhatia, the John and Dorothy Wilson Professor of Health Sciences and Technology and of Electrical Engineering and Computer Science at MIT, and a member of MIT’s Koch Institute for Integrative Cancer Research and the Institute for Medical Engineering and Science (IMES).

or the very first time, biologists packed nonliving components into a cell-like membrane, piece by piece, and witnessed the bag of molecules start to behave like life. The lab-made synthetic cell grew, replicated its DNA, and divided, demonstrating the basic functions of a cell cycle.

It’s “an impressive step,” said Jack Szostak, who studies the origins of life at the University of Chicago and was not involved in the research. “I don’t know of any other effort to put together an artificial cell from biological components that has progressed so far.”

The cell is not alive by any definition. It can’t survive without constant deliveries of food and ribosomes, the machinery needed to make proteins. It has no defenses or a good waste removal system. But it’s the strongest demonstration yet that it is possible to generate life from nonlife, a goal that synthetic biologists have been chasing for decades.

“It’s a big step forward to this holy grail of making a living thing out of dead components,” said Sijbren Otto, a systems chemist at the Stratingh Institute for Chemistry in the Netherlands who was not involved in the work. “It’s not completely there yet, but it’s definitely getting quite close.”

Since these cells were pieced together from scratch, and all the molecular parts were crafted in the lab, scientists can tinker with the system and switch components in and out. “I have a blueprint, I have a full chemical ingredient list of every component,” said Kate Adamala, a synthetic biologist at the University of Minnesota who led the new study, which is not yet peer-reviewed. With such flexibility, this kind of synthetic cell could eventually be coaxed to create new materials, such as biofuels and drugs, and help researchers study disease.

A study is reframing a fundamental question in plant evolution: What made trees possible? Researchers from Cal Poly Humboldt, Yale University, the University of Hohenheim in Germany and the Czech Academy of Sciences set out to understand how trees evolved and what allowed them to become some of the largest and longest-living organisms on Earth.

The Current Biology study suggests that surviving drought may have been a powerful force shaping the evolution of trees. It challenges conventional ideas about what defines a tree.

Rather than viewing trees simply as plants with trunks and wood, the researchers argue that a defining feature may be their ability to add and replace water transport tissues throughout their lives. Becoming tree-like and growing taller to compete for sunlight, they argue, required solving a critical challenge—moving water through a massive organism.

Water became the central challenge
To grow tall, trees must move water upward from their roots to their trunks, branches and leaves. But as they grew larger, keeping more and more water moving became increasingly difficult, especially when water became scarce.

Xylem, the microscopic tubes that carry water through plants, can become blocked by air bubbles called embolisms. If those blockages spread, they can cut off water to the rest of the plant and kill it. As plants evolved larger and more extensive water-transport systems, they became more vulnerable to embolisms and hydraulic failure.

But tree-like plants, the researchers propose, started to compartmentalize these systems to limit the spread of damage.

The strategy is similar to a power grid with circuit breakers or a ship with watertight compartments: If one section fails, the entire system doesn't go down with it.

That led the researchers to a new conclusion: The evolution of trees may have been driven by the need to move more water through their increasingly taller bodies and survive hydraulic failure...

Charting the vast Jovian realm: NASA's Juno mission provides new maps of the giant planet Jupiter. ‍This is a cylindrical composite map from Juno's 9th close pass by Jupiter 🗺️ missionjuno.swri.edu/junocam/think-…

Pesky mosquitoes on the hunt for blood may find the smell of a common repellent attractive, not repulsive. That’s the finding of new lab tests.

The chemical is known as DEET. It’s been one of the most effective insect repellents for decades. But in new lab tests, yellow-fever mosquitoes (Aedes aegypti) exposed to DEET learned to associate the chemical with food. This suggests these insects can link unpleasant odors with rewards. That turns a bad experience into an inviting one.

For now, it’s not clear if this might happen outside the lab, too.

How DEET works, exactly, is a bit unclear, says Clément Vinauger at Virginia Tech in Blacksburg. He studies animals’ brains and behaviors. Some studies have suggested mosquitoes don’t like DEET’s smell or taste. Others hinted that the repellent scrambles mosquito senses. That would keep the insects from detecting the otherwise enticing body odors that normally lure them in for a blood meal.

The new results suggest that mosquitoes do detect DEET, Vinauger says. They also can learn, changing their behaviors based on prior experiences.

NASA on Tuesday announced new uncrewed missions to aid in the future creation of a lunar surface base, a project beginning to take shape despite recent setbacks.

Three U.S. companies were awarded contracts for missions to deliver cargo, including scientific instruments, to the moon, NASA said. The agency will pay nearly $600 million for the projects, which supplement others announced in May.

The efforts are part of plans to use robotic vehicles to build infrastructure that future human explorers to the moon could eventually use.

The announcement comes as the U.S. space agency's lunar ambitions have faced setbacks following the spectacular explosion this spring of the New Glenn rocket, which is built by tech billionaire Jeff Bezos' company Blue Origin.

Senior agency officials have acknowledged that the situation would likely cause lunar program delays but voiced optimism Tuesday, also indicating there were alternatives to launch a lander carrying equipment developed by Blue Origin.

"We're working with Blue Origin very closely to understand their timelines to recovery and also looking at other options in case it doesn't meet our timeline," said Carlos Garcia-Galan, NASA program manager for the moon base, during an event with journalists Tuesday.

After spending years creating a lunar orbital space station known as Gateway, NASA overhauled its plans in March, saying it would now focus on creating a base for surface operations.

The agency pledged $20 billion to the moon base efforts.

The base is planned for a site near the lunar south pole, a strategic area because of the presence of water ice in the soil. NASA had previously said construction could begin in 2029.

Conceived to compete with China—which also aims to send humans to the moon and establish a base there—NASA's ambitious plan remains vague in several aspects.

But the U.S. agency has started to roll out its vision, which includes lunar landers, lunar rovers and drones designed to survey the terrain and subsequently build up infrastructure, including a power grid and pressurized habitats.

The agency on Tuesday floated the possibility of repurposing a Mars rover as part of the efforts it is aiming to complete in a tight time frame.

A rush rescue mission to save a NASA space telescope remains grounded, this time because of a last-minute launch problem.

Northrop Grumman 's rocket-launching plane took off from the Marshall Islands in the Pacific on Thursday, following weather delays all week. While in flight, the team observed a warning in the stream of data and decided against releasing the Pegasus rocket strapped to the plane's belly, the company said. It was not immediately clear whether the warning came from the rocket or the plane.

The rocket holds a three-armed robotic spacecraft built by Katalyst Space Technologies to capture the Swift Observatory, which will come crashing down by October if no help arrives. No new launch date has been set.

NASA paused Swift's science operations earlier this year to preserve its orbit as long as possible. It has detected thousands of gamma ray bursts and exploding stars since its launch in 2004, tipping off other telescopes for more detailed observations.

Anxious to continue Swift's scanning of the universe, the space agency hired Katalyst Space last September for the $30 million salvage operation.

The hantavirus outbreak that struck a cruise ship in April, killing three people and sparking fears of further spread, is over, the World Health Organization (WHO) has announced.

"Today, the final contact of a person exposed to hantavirus on the cruise ship MV Hondius completed their quarantine period, tested negative and returned home. No further cases have been reported since the 25th of May," Tedros Adhanom Ghebreyesus, the WHO's director-general, said in his opening remarks at a news conference Thursday (July 2). "We are therefore very pleased to say that WHO considers the outbreak of hantavirus over."

The total number of cases linked to the outbreak was 13. All those affected were either passengers or crew on the ship.

The outbreak began aboard the Dutch-flagged cruise ship MV Hondius after it departed southern Argentina on April 1. It involved the Andes virus, the only known hantavirus that can spread between people.

Hantaviruses are rodent-borne viruses that are found in the Americas, Europe and Asia and spread to humans relatively rarely, usually via contact with the urine, droppings or saliva of infected rodents. The Andes virus, however, has sparked short chains of human-to-human transmission in the past.

A light intro to LLMs, chatbots, pretraining, and transformers.

Dig deeper here:
Neural networks  
Technical details as a talk:
Visualizing transformers and attention

The giant trees of tropical forests are important allies in the fight against climate change because of their ability to store carbon, yet they are still poorly understood by science. However, a study published in the journal Science reveals a crucial survival mechanism: These trees, which exceed 70 meters (230 feet) in height, have no difficulty transporting water to their tops and are no more vulnerable than smaller trees.

They have developed internal adaptations that compensate for the challenges of transporting water to the highest branches. Furthermore, tests conducted during severe droughts showed that they did not experience a more pronounced decline in growth than smaller trees. This contradicts the hypothesis that very tall trees would be more susceptible to water stress.

How giant trees move water
To date, the scientific literature suggests that as trees grow taller, their ability to move water upward is impaired by the greater distance between roots and leaves, as well as by the effects of gravity. This would reduce photosynthesis, limit growth and increase vulnerability to drought.

The research found that adjustments to the xylem conduits (microscopic "tubes" that the plant uses to transport water and nutrients to the leaves)—which increase in diameter as the tree grows taller—compensate for the increased resistance to water flow along the way. In practice, it's as if a larger hose were needed to carry water further. These complex adaptations reduce the likelihood of water transport failure when the plant is in drought conditions.

An international team of quantum researchers has shown how machine learning can be used to filter a practically infinite number of possible material combinations to identify candidates for superconductivity. Thanks to the breakthrough, new superconductors can now be found much faster, says Aalto University Professor Päivi Törmä, who leads the SuperC consortium behind the research.

Superconductors carry electric current with zero resistance, thanks to a quantum effect appearing only at extremely low temperatures. They power not only quantum computers but many other things, from neuroimaging to fusion reactors and maglev trains.

However, these unicorn materials are prohibitively hard to identify. Any endlessly variable combination of elements could be a superconductor—yet few actually are. And the ones already discovered require expensive cooling equipment to bring them to the near-absolute-zero temperatures that give them their quantum properties.

For scientists the world over, the race is on to find a scalable superconductor that works at room temperature.

"Superconductive materials that can operate at room temperature would forever change the way we consume energy," explains Törmä. "If such a material could replace regular conductors in applications like computers and data centers, global energy consumption could be slashed and the heat footprint of the ICT sector vastly reduced."

Arriving at proof of concept
Driven by a shared desire to harness quantum physics in the fight against climate change, Professor Törmä and a team of renowned physicists formed the SuperC consortium in 2023. It is the first coordinated global collaboration to find new superconductors—and they aim to find a room-temperature superconductor by 2033.

According to Törmä, SuperC's combination of quantum geometry and machine learning gives them an excellent starting point. This latest discovery has its underpinning in traditional Japanese basket-making patterns; both of the newly discovered materials (YRu3B2 and LuRu3B2) gain their superconductivity from electrons forming flat bands in a traditional pattern known as a kagome lattice.

To identify the two new superconductors, the team used machine learning to narrow down promising elemental combinations. After prescreening these with a unique algorithm, the team carried out detailed calculations to determine which materials could be superconductive.

After theoretical confirmation, SuperC collaborators at Rice University set about synthesizing the samples. This complex process, which involves chemically combining raw elements into new compounds, was led by Professor Emilia Morosan. The team at Rice was then able to run tests on the materials to confirm their superconductivity.

A new study by a doctoral researcher at The University of Alabama in Huntsville (UAH), part of The University of Alabama System, suggests global dust storms on Mars may organize the Martian atmosphere into regions favorable for electrical activity, increasing the potential for electrostatic discharges that could affect missions to the red planet by interfering with electronics, causing arcing between conductive surfaces, and damaging exposed scientific instruments and spacecraft systems. The research, conducted by Chali Idosa Uga, a third-year Ph.D. student in the Department of Space Science at UAH, is published in The Planetary Science Journal.

The work focuses on the Martian Year 34 global dust storm, a planet-encircling event that occurred on Mars in 2018. It is one of the best-studied Martian weather events because multiple orbiters and rovers observed it simultaneously. Uga's research focused on whether such events can create conditions in which electric fields may build up to levels favorable for electrical breakdown in localized regions of the lower atmosphere. The researcher was advised by Dr. Gary Zank, director of the UAH Center for Space Plasma and Aeronomic Research (CSPAR), and Dr. Dennis Gallagher at NASA Marshall Space Flight Center.

"Mars does not have thunderstorms in the terrestrial sense, but it does have intense dust storms in a thin carbon dioxide atmosphere," Uga explains. "During such events, dust is lifted, transported and mixed through the lower atmosphere, creating conditions in which grain collisions can separate electric charge while the weakly conducting atmosphere may allow that charge to persist."

Electrified dust as a mission hazard
The study also highlights potential implications for future Mars missions, which may need to account for electrostatic environments during dust storms.

"For future Mars exploration, our study suggests that major dust storms should be evaluated not only as atmospheric, thermal and visibility hazards, but also as structured electrostatic environments," Uga notes. "We do not quantify risk to a specific spacecraft, habitat, instrument or communication system. What we show is that during the Martian Year 34 global dust storm, the lower atmosphere developed localized and altitude-dependent regions where charge separation could persist, and modeled electric fields approached breakdown-favorable conditions."

A mysterious wavelength of light is missing from the dwarf planet Pluto and Saturn's supersized moon Titan, new James Webb Space Telescope (JWST) observations show. The surprising discovery hints that these worlds harbor an unknown molecule that has not been seen in any other solar system world or exoplanet so far.

Every element or molecule in the universe absorbs unique wavelengths of electromagnetic radiation. Therefore, one of the main ways astronomers study distant worlds — both inside and outside the solar system — is by closely examining the light that reflects off them and searching for dark "absorption lines" that correspond to the wavelengths of known chemical compounds.

For example, molecular oxygen absorbs light at 230 nanometers, so if the electromagnetic spectrum of a faraway exoplanet has an absorption line at this frequency, researchers can be confident that its atmosphere contains oxygen, according to a 2021 study.

JWST has proved to be exceptionally good at capturing electromagnetic spectra and identifying specific chemicals in exoplanet atmospheres, around distant stars and within primitive galaxies. It has even identified a molecule on one alien world that could point to extraterrestrial life.

In a new study, uploaded June 11 to the preprint server arXiv, researchers analyzed JWST data from Pluto and Titan, focusing on very small wavelengths that have been relatively unexplored until now. This revealed a specific absorption line at around 5.11 micrometers in both worlds' spectra. (These findings have not been published in a peer-reviewed journal yet.)

The team pored through similar studies on other planetary spectra but "did not find any band referenced in these publications that corresponds to the location of the observed absorption in Titan and Pluto," the researchers wrote in the paper.

A molecular mystery
The discovery is even stranger because there are very few similarities between Pluto and Titan that could explain why they share a molecule not found anywhere else.
...
The researchers proposed that it could be benzene — a ring-shaped hydrocarbon — mixed with an unknown molecule, or some form of acetylene or ketene ice. However, much more work is needed to prove that any of these potential candidates are responsible for absorbing this specific wavelength, they wrote.

Researchers at the Karlsruhe Institute of Technology (KIT) have found how plant cells respond to stress. If their energy supply is disrupted by heat, drought or saline soils, chloroplasts—the cells' powerhouses—send an intracellular distress signal by forming tiny, finger-like projections. This signal specifically activates protection programs that help limit damage. The study, published in Plant Physiology, reveals the function of these previously mysterious structures and presents an approach for making crops more resilient to climate stress.

Each plant cell contains chloroplasts, which work like little solar power stations. The tiny structures are the green energy centers of plant cells. Absorbing sunlight and extracting carbon dioxide from the air, they produce sugar—the energy source every plant needs for growth and survival. Without these solar power stations, plants would not be able to produce energy and thus could not serve as a food resource for other living beings. Another effect would be that less oxygen would be released into the atmosphere.

Protection against heat, drought, or salt
If plants are under stress because of, for example, a lack of water, high temperatures such as those Germany and Central Europe are currently experiencing, or saline soils, this delicate energy system gets out of balance. Aggressive substances develop that can affect and damage important parts of the cell. To survive, the plant needs to respond quickly and activate protective measures.

In this stress situation, chloroplasts react by forming the "fingers" that were recently investigated. The researchers revealed that these structures send a signal to the central control of the cell. "Particular genes are enabled or disabled, which triggers protection programs that support the damaged areas," said Professor Peter Nick from KIT's Botanical Institute.

The human brain evolved for a world of familiar faces, immediate threats and small social groups. But the world around us is changing far faster than human biology can keep pace. That mismatch may help explain some of the stress, loneliness and constant comparison people experience today.

The review, co-authored by Dr. Jose Yong, senior lecturer at James Cook University, Singapore, and Dr. Sarah Chan, research fellow at the Lee Kuan Yew Centre for Innovative Cities at SUTD, is published in Behavioral Sciences. Titled Evolutionary mismatch, stress, and competition: Making sense of psychosocial problems in the polycrisis era, it examines how stress, competition and loneliness can be understood through an evolutionary lens.

Evolutionary mismatch describes what happens when human instincts shaped in one kind of environment are forced to operate in a very different one. Humans evolved in smaller, close-knit groups, where danger, belonging, status and trust were read through familiar people and everyday face-to-face signals. Now, those same instincts are being triggered in dense cities, digital platforms, unequal societies and a world shaped by overlapping pressures. The result is internal confusion: Responses that once made sense in a small, familiar group can feel out of place, or simply overwhelming, in modern life.

Social media makes this mismatch especially visible. The urge to understand our place within a group may once have helped people maintain trust and cooperation among familiar faces. Today, that same instinct can be triggered by an endless stream of curated lives, achievements and status signals.

At the center of the paper is competition. Modern environments can intensify the feeling that others are judging, outperforming or leaving us behind. The authors propose that this heightened sense of competition may be one pathway through which evolutionary mismatch contributes to stress and poorer well-being.

"Competition is not new, but modern life can make it feel constant," said Yong. "An evolutionary perspective may help explain why people respond so strongly to comparison and the fear of falling behind, even when those signals come from strangers or screens rather than a small social group."

The paper draws on existing research and theory rather than new data. It presents evolutionary mismatch as one way of understanding modern social and psychological problems, alongside psychological, social and economic explanations. These ideas will need to be tested through real-world research.

That matters because the response to modern stress cannot rest only on telling individuals to be more resilient. If environments are activating old instincts in new and unhelpful ways, then cities, workplaces, digital platforms and communities also need to be part of the solution.

The state of the Atlantic Meridional Overturning Circulation (AMOC) has been a hot topic among climate scientists in recent years. The AMOC is crucial for climate regulation because it pulls warm surface water from the tropics north and sends colder, deeper water south, redistributing large amounts of heat, helping to sustain marine ecosystems and keeping global weather patterns steady. However, most standard AMOC-focused climate models may be missing an important piece of the puzzle—they don't include the growing pulse of freshwater from Greenland ice melt, which could further disrupt the AMOC.

But now, a study published in Science Advances has incorporated the freshwater influx from Greenland's ice melt into a new model. The results show that while the meltwater plays a significant role, it may not push the AMOC over the edge just yet.

To tip or not to tip?,
Most climate models agree that the AMOC will continue to weaken this century, but the abrupt collapse that some models suggest remains debated. A recent Intergovernmental Panel on Climate Change (IPCC) model found that none of the Coupled Model Intercomparison Project phase 6 (CMIP6) models show an abrupt AMOC collapse during the 21st century.

Yet another recent study found that the Atlantic "cold blob" indicated a tipping point was nearing if conditions worsen. Earlier work has suggested that the Greenland meltwater contributes to the weakening of the AMOC, but it's been unclear whether that weakening would lead to an abrupt tipping point in which the AMOC collapses completely or is very difficult to reverse.

"However, it currently remains an open question whether these meltwater-induced AMOC changes are associated with tipping point characteristics such as abruptness and irreversibility. In addition, the physical mechanisms of how Greenland meltwater affects the AMOC beyond 2100 have, to our knowledge, not yet been explored," write the authors of the new study.