A large new review finds that adults with lower vitamin D levels are more likely to have depression, especially when 25-hydroxy-vitamin D [25(OH)D] falls at or below 30 nmol/L. The work, published in Biomolecules and Biomedicine, also makes clear that this pattern does not yet prove that low vitamin D causes depression.

Depression affects about 5% of adults worldwide and is expected to become the leading cause of disease burden by 2030. Standard antidepressants help many people but, on average, provide only “small to moderate” effects, which has kept interest high in safe, modifiable factors like vitamin D.

From a biological perspective, the connection makes sense. Vitamin D receptors are abundant in mood-relevant brain regions, including the hypothalamus and pons. Its active form, 1,25-dihydroxy-vitamin D, supports healthy brain signaling, calms neuro-inflammation, limits oxidative stress, and helps keep intracellular calcium in balance, all pathways that have long been tied to depression.

What's so special about comet 3I/ATLAS? It's only the third object we’ve ever found passing through our solar system from elsewhere in the galaxy. NASA's fleet of spacecraft is making coordinated observations of the comet. Some of what they've seen so far: go.nasa.gov/3IATLAS

🌌 All images, old and new, are in the comments

You can track the comet yourself anytime using our "Eyes on the Solar System" online experience, which simulates the current, past, and future positions of planetary objects and spacecraft using real NASA data: eyes.nasa.gov/apps/solar-sys…

The kind of view that makes you stop scrolling for a moment. ✨

Captured in a timelapse from the International Space Station, this sequence follows Earth as auroras ripple beneath the station and sunrise slowly edges over the planet’s curve. What begins as a quiet glow on the horizon becomes a full sweep of daylight in seconds, a transition you can only witness from orbit 250 miles above our world.

For decades, scientists have targeted the sticky protein clumps that amass in Alzheimer's brains as a potential way of treating the disease, but they may have been off the mark.

A new study shows that clearing away the amyloid-beta clumps doesn't appear to repair key brain functions.

In particular, it doesn't restore the brain's mechanisms for clearing out waste, known as the glymphatic system. This system is known to be impaired in people with Alzheimer's, and would usually help with getting rid of excess amyloid-beta plaques, via waves of cerebrospinal fluid (CSF).

The study comes from researchers at the Osaka Metropolitan University in Japan, who tested the new Alzheimer's drug lecanemab on 13 people with the disease. Magnetic resonance imaging ( MRI) scans were used to look at the effects on the brain.

"Even when amyloid-beta is reduced by lecanemab, impairment of the glymphatic system may not recover within the short-term," says medical researcher Tatsushi Oura, of Osaka Metropolitan University.

Mutations in a gene associated with Crohn's disease have been found to rob critical immune cells of their ability to switch modes, causing them to overreact and trigger inflammation.

Variations in the NOD2 gene have been linked to Crohn's in previous studies, yet their exact role in the disease's pathology has long been a mystery.

Researchers from the University of California, San Diego used machine learning techniques to identify patterns in gene activity of immune cells in the gut.

Experiments on lab-grown cells and samples from both healthy guts and digestive tracts with a form of Crohn's called inflammatory bowel disease (IBD) revealed that the mutations interfere with typical protective mechanisms that allow NOD2 proteins to guard against IBD.

Tracking the behavior of immune cells called macrophages through the expression of their genes, the researchers discerned which cells helped the gut stay healthy and which became inflammatory and caused damage.

"The gut is a battlefield, and macrophages are the peacekeepers," says UC San Diego Gajanan Katkar. "For the first time, AI has allowed us to clearly define and track the players on two opposing teams."

The rapid rise of ChatGPT and other generative AI systems has disrupted education, transforming how students learn and study.

Students everywhere have turned to chatbots to help with their homework, but artificial intelligence's capabilities have blurred the lines about what it should—and shouldn't—be used for.

The technology's widespread adoption in many other parts of life also adds to the confusion about what constitutes academic dishonesty.

Here are some do's and don'ts on using AI for schoolwork...

☄️ 40 000 near-Earth asteroids discovered!

Thankfully, none of them are cause for concern for the foreseeable future, but ESA's planetary defence teams are keeping a watchful eye on the skies.

esa.int/Space_Safety/P…

Over the course of billions of years, the universe has steadily been evolving. Thanks to the expansion of the universe, we are able to "see" back in time to watch that evolution, almost from the beginning. But every once in a while we see something that doesn't fit into our current understanding of how the universe should operate.

That's the case for a galaxy described in a new paper published in The Astrophysical Journal Letters by Ph.D. student Sijia Cai of Tsinghua University's Department of Astronomy and their colleagues. They found a galaxy formed around 11 billion years ago that appears to be "metal-free," indicating that it might contain a set of elusive first generation (Pop III) stars.

Before we get into the discovery itself, some context is necessary. Population III (Pop III) stars are considered to be the first generation of stars that formed early in the universe's history. Importantly, they have essentially no "metal," which in cosmological terms means any element other than helium and hydrogen. Since those heavier elements can only be formed in stars themselves (or in the supernovae they create), by definition the first generation of stars can't contain them.

Cosmologists have been searching for examples of these Pop III stars for decades, but so far have been unable to find them. Typically, they search a time of the universe's history known as the Epoch of Reionization, which took place up to 1 billion years after the Big Bang, when the universe was very young and we believe the first stars themselves were starting to form.

So imagine the author's surprise when they found a galaxy that appeared about 2 billion years later than the Epoch of Reionization. By that point, plenty of stars should have lived and died, with their remnants "infecting" any nearby gas and dust clouds, or other stars themselves, with the metal they created. That was the theory at least.

But, using data gathered by the James Webb Space Telescope (JWST), the Very Large Telescope (VLT), and the Subaru Telescope, the authors identified a galaxy they called MPG-CR3 (or CR3 for short). The spectral signature of this galaxy was unique among all other galaxies of that era. It had very clean hydrogen and helium lines, and, notably, almost a complete lack of "metals" like oxygen in its spectral signature. In fact, the upper limit of the metallicity of the stars in the galaxy puts them at .7% of the metallicity of our sun.

Even more interestingly, the galaxy itself only appears to be about 2 million years old—making it relatively young by galactic standards. We are able to see it at such a young age, despite it being formed billions of years ago, because of the expansion of space-time. CR3 also appears to be relatively "dust-free," and have relatively small stars, especially for such an ancient galaxy. Most galaxies during Cosmic Noon have supermassive stars compared to our own.

Despite intense UV radiation and temperature swings, most spores remained viable when returned to Earth. Their protective casing acts as a natural shield, enabling resilience even scientists didn’t expect. The results open doors to using hardy plants for future off-world agriculture.

Moss Resilience From Earth to Space
Mosses are known for their ability to flourish in some of the harshest locations on the planet, from high mountain ranges like the Himalayas to the scorching terrain of Death Valley, as well as the frozen Antarctic tundra and even the cooling surfaces of active volcanoes. Their remarkable toughness inspired researchers to send moss sporophytes, which are reproductive structures that contain spores, into what may be the most inhospitable environment of all: outer space. The study, published in iScience today (November 20), reported that more than 80% of the spores endured 9 months outside the International Space Station (ISS) and returned to Earth still able to reproduce. This marks the first documented instance of an early land plant surviving long-term direct exposure to space.

“Most living organisms, including humans, cannot survive even briefly in the vacuum of space,” says lead author Tomomichi Fujita of Hokkaido University. “However, the moss spores retained their vitality after nine months of direct exposure. This provides striking evidence that the life that has evolved on Earth possesses, at the cellular level, intrinsic mechanisms to endure the conditions of space.”

Fujita first began considering the idea of testing moss in space while examining plant evolution and development. Mosses seemed exceptionally capable of settling in places that challenge most forms of life. “I began to wonder: could this small yet remarkably robust plant also survive in space?”

🌙 Argonaut's lunar lander family grows.
🚀 Starting in 2030, esa's Argonaut will deliver vital cargo to the Moon's surface.
🤝 Meet the partners getting us there 🔗 esa.int/Science_Explor…
🇮🇹🇫🇷🇬🇧🇩🇪 Thales Alenia S, OHB SE, Nammo

Researchers at the Ruđer Bošković Institute (RBI) in Zagreb, Croatia, have uncovered that the protein CENP-E, once thought to function as a motor pulling chromosomes into position during cell division, actually serves a different purpose. Rather than dragging chromosomes, CENP-E stabilizes their initial connections to the cell’s internal “tracks,” ensuring they are properly aligned before being separated.

In a complementary study, scientists also discovered that centromeres—small structures within cells once believed to work independently—actually guide this essential protein to help maintain accurate cell division. These findings overturn more than twenty years of established textbook knowledge and have major implications for the life sciences, as mistakes in this process are linked to cancer and genetic disorders.

Every second, trillions of times over, the human body performs an extraordinary feat. A single cell prepares to divide, containing three billion DNA letters, and somehow guarantees that both daughter cells inherit precise copies of this genetic code.

When that precision falters, the outcome can be devastating. Even one misplaced chromosome can disrupt development, lead to infertility, or trigger cancer. Cell division is among the most exacting processes in biology.

For decades, researchers believed they understood at least one of the key components involved: CENP-E, described as a molecular motor responsible for pulling stray chromosomes to the center of the cell to ensure proper division. The explanation was tidy, convincing, and ultimately incorrect.

Two new studies from RBI, published in Nature Communications and led by Dr. Kruno Vukušić and Professor Iva Tolić, have redefined that understanding and proposed new mechanisms for how CENP-E functions. Dr. Vukušić, a leading young researcher in cell biology, completed his postdoctoral work within an elite ERC Synergy team and is now preparing to form his own research group at RBI. Professor Tolić, an internationally recognized cell biologist who heads the Laboratory for Cell Biophysics at RBI, has received two ERC grants and is a member of EMBO and Academia Europaea. Together, their combined expertise revealed that CENP-E is not the system’s motor but its regulator—the crucial switch that activates at just the right time to ensure flawless coordination of chromosome movement.

“CENP-E is not the engine pulling chromosomes to the center,” Vukušić says. “It is the factor that ensures they can attach properly in the first place. Without that initial stabilization, the system stalls.”

X-59 has officially completed its first flight ever!

The NASA X-59 quiet supersonic research aircraft took to the skies for the first time Oct. 28, marking a historic moment for the field of aeronautics research.

✈️A culmination of all the right stuff: go.nasa.gov/3K3QsnC

How fast and in what direction is our solar system moving through space? This question, though simple in appearance, plays a central role in testing modern cosmological theories.

A team led by astrophysicist Lukas Böhme at Bielefeld University has now uncovered results that call the standard cosmological model into question. Their findings were recently published in Physical Review Letters.

“Our analysis shows that the solar system is moving more than three times faster than current models predict,” says lead author Lukas Böhme. “This result clearly contradicts expectations based on standard cosmology and forces us to reconsider our previous assumptions.”

A New Look at the Radio Galaxies of the Sky
To measure the solar system’s motion, the team examined the distribution of radio galaxies—distant galaxies that emit strong radio waves, a form of electromagnetic radiation with long wavelengths similar to those used in radio communication. Because radio waves can pass through dust and gas that obscure visible light, radio telescopes can detect galaxies that optical instruments cannot.

As the solar system travels through the universe, its motion produces a faint “headwind,” causing slightly more radio galaxies to appear in the direction of motion. This difference is extremely small and can only be identified through highly precise observations.

Fossilized remnants of ancient carbon from the heart of South Africa's Mpumalanga province have just yielded the earliest chemical evidence yet of life on Earth.

According to a new analysis using machine learning, fragmentary traces of carbon from the Josefsdal Chert, dating back 3.33 billion years, are the earliest and most confident detection of biotic chemistry found on Earth to date.

In addition, the team's work identified the oldest evidence for photosynthesis to date in rocks 2.52 and 2.3 billion years old, from South Africa and Canada, respectively – pushing back the documented timeline for the process by more than 800 million years.

"Our results show that ancient life leaves behind more than fossils; it leaves chemical 'echoes'," says mineralogist and astrobiologist Robert Hazen of the Carnegie Institution for Science in the US. "Using machine learning, we can now reliably interpret these echoes for the first time."

Time, decay, and geology are not kind to the traces life leaves behind – and the greater the passage of time, the greater the opportunity for degradation.

In addition, the first life to emerge on Earth would have been tiny microbes, scientists believe, whose physical remnants would have been dramatically altered in the billions of years since they first wiggled around in the primordial damp.

That's not to say they left no traces. Based on their physical structure, formations such as stromatolites are interpreted as the remains of microbial mats, vast communities of microbes so numerous that they left behind layers in ancient rock. There is also black chert and shale, as well as carbonate formations, within which ancient, fragmentary traces of fossilized carbon have been retained over eons.

It's difficult to determine with certainty, however, whether these sooty remnants of highly altered carbon were produced by biological or non-biological processes.

Now, a team led by Hazen, in a paper with Carnegie Science astrobiologists Michael Wong and Anirudh Prabhu as first authors, developed a way to positively identify ancient carbon produced by life.

Can you be-leaf it’s fall? We sure can — especially with NASA’s PACE satellite!

PACE can detect subtle shifts in leaf color that our eyes can’t see, helping scientists track changes in fall foliage to better understand these ecosystems. Now that’s some good leaf peeping! 🍁