13 February 2026

Today’s Logbook from Science Online News Editor David Grimm goes behind the scenes of his feature story on guide dogs. But first, catch up on the latest science news, including how scientists might save the American chestnut and how myelin can be repaired.

Astronomy | News from Science

Now you see it, now you don’t

Astronomers have witnessed a giant star vanish in a nearby galaxy. The disappearance, they say, shows how dying stars can collapse straight into a black hole without the supernova blast that such implosions usually produce.

In the standard picture of a star’s death, once it has burned up its fuel, the core collapses. Small stars collapse into small cinders called white dwarfs. But stars more than about eight times the mass of the Sun don’t go quietly. The core collapses so violently and completely that it generates a rebounding shockwave that blasts the star’s outer layers into space in a bright ball of debris: a supernova. The collapse leaves behind a neutron star, where the mass of a star is packed into a ball the size of a city, which can later become a black hole if enough leftover star material falls onto it.

But what if the original star is so massive that its core collapses straight past the neutron star phase into a black hole? One promising candidate for such a death was reported in 2015, but now astronomers have found a more solid one in the nearby Andromeda galaxy. The star brightened in 2014 and began to dim a couple days later before it vanished. Last year, NASA’s JWST found just a faint glow in infrared light at the site of the vanished star: a cloud of gas and dust left behind. It’s possible that the star is still there but has dimmed or been cloaked by a different process. The only way to tell is to watch and wait, perhaps for decades.

If collapsing straight into black holes proves more common than theorists thought, they’ll have to find a new way to explain how heavy elements are made. The explosive deaths of stars are thought to provide the right conditions to forge most elements heavier than iron, gradually filling galaxies with the stuff to make rocky planets and everything that lives on them. “If the supernova rate was lower than we’ve predicted because of failed supernovae, it could affect what we know about galaxy evolution as well,” said astronomer Emma Beasor.

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Conservation Genetics | Science

New hope for an old chestnut

American chestnut trees with blight: One infected (L) and one exhibiting resistance (R). The American Chestnut Foundation

During the first half of the 20th century, a deadly fungal pathogen ravaged chestnut forests across the eastern United States, killing off billions of trees from Maine to Mississippi. Although many root systems still persist, new saplings often succumb to the blight before they reach maturity; this once-dominant species is currently considered functionally extinct. Now, scientists may have found a way to bring the iconic tree back from the brink.

Although researchers have long tried to restore the American chestnut by breeding it with blight-resistant Asian chestnut trees, progress has been slow—in part because the genetic underpinnings of blight resistance remain murky. In a new study, scientists pieced together the genomes of three important founder chestnuts used in hybrid breeding programs. The work revealed that, while most protein-coding genes are shared between different chestnut species, the Chinese chestnut appears to have more copies of certain defense-related genes. Metabolite profiling also showed that the Chinese chestnut contains high levels of compounds that inhibit fungal growth. Careful interbreeding, the team reports, could result in hybrid trees that are highly resistant to blight and root rot while still maintaining an average of 70% to 85% American chestnut ancestry.

“Despite decades of work, producing a blight-resistant American chestnut tree that can fully compete in natural forest settings has been unsuccessful,” forest biotechnologist Steven Strauss and geneticist Gancho Slavov write in a related Science Perspective. “What is needed now are long-term, multigenerational projects that leverage the most advanced technologies available, including genomic selection, gene editing, and gene transfer.”

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Neuroscience | Science

My oh myelin

Debilitating nervous system disorders like multiple sclerosis damage a special membrane that encases axons, called myelin. Because myelin helps neurons conduct electrical signals, its damage harms important nervous system functions like cognition, memory, movement, and perception. But once myelin is damaged, new research published in Science suggests not all may be lost.

To study myelin, researchers began by inducing different kinds of myelin injuries in zebrafish and rodents, noticing that myelin swelling was the first result. But consistent imaging of the swelling over time revealed that loss didn’t always follow; sometimes, the sheaths healed. To determine how, the researchers tried different behavioral tests, as well as drugs and genetic interventions. They found that nervous system activity after damage exacerbated myelin swelling, while nervous system rest allowed the myelin to continue functioning.

Lastly, the researchers imaged ex vivo human tissues with multiple sclerosis and saw evidence of myelin swelling. This led them to conclude that nervous system rest could be an important treatment for preventing myelin loss.

In a related Perspective, neuroscientists Kamsi Nwangwu and Michelle Monje note that nervous system rest may only be recommended in the short-term. Much like with a traumatic brain injury, they write, it’s possible that “prolonged rest prevents the activity-dependent mechanisms of myelination that would support long-term recovery .” In other words, rest up, then get back to moving and grooving.

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Logbook

Our intrepid reporter navigates an obstacle course at Guiding Eyes for the Blind with the help of a faithful companion. Zoe Bennett/Guiding Eyes

Dogs lead the way

David Grimm, Online News Editor, News from Science

Navigating an obstacle course with uneven, cracked sidewalks, low bridges, and eye-level tree branches that seem to come out of nowhere is difficult enough. But I was doing it blindfolded. My only guide on this journey was a yellow Labrador retriever, who seemed far more confident than I was.

I had first tried the course without the dog, feeling my way with a long white cane. Every step felt like a blind leap across a chasm. I walked slowly and tentatively, convinced I was about to smack into a tree or fall on my face.

With the dog, everything changed. Though I was nervous at first, I quickly put all of my faith in the Lab, trusting her like a friend who just wanted to get me home safely after a long night of partying. She moved quickly and assertively, and I never once felt like I was going to trip off a sidewalk or smack my head on an overhang. When I tried the course with a cane, it took me more than 10 minutes to complete it; with the dog, I cleared it in less than two minutes. It was the difference between driving a car down a winding road at night with no lights on, and putting the vehicle on autopilot.

I was at the main campus of Guiding Eyes for the Blind in Yorktown Heights, New York—about an hour’s drive north of New York City—where working dogs are being trained to help people with visual impairments navigate a world that’s far more challenging than my little obstacle course. They must help their handlers cross busy streets, board crowded subway cars, and steer a steady path through a frantic, unpredictable world. They also can’t be afraid of the rumble of garbage trucks; they can’t be aggressive towards other dogs or people; and they must not tear off after squirrels, cats, or a hamburger someone has dropped. And, perhaps most importantly, they must know when to obey commands, and when to defy them—a remarkable skill known as intelligent disobedience that can save their human’s life.

The skillset of guide dogs is so complex, more than half won’t graduate, even at prestigious facilities like Guiding Eyes for the Blind. These schools—and others like them throughout the world that train not just seeing eye dogs, but also canines that help kids with autism, adults with PTSD, and individuals with a wide range of other challenges—can spend more than two years and tens of thousands of dollars to produce working dogs, and yet they often end up with canines better suited for couch crashing than sidewalk surfing.

That’s why I had come to Guiding Eyes in the first place. About four years ago, I came across a scientific study detailing new ways that science could improve the working dog pipeline . The paper largely focused on “estimated breeding values”—statistical calculations that estimate the likelihood that an animal will pass on a trait of interest to the next generation. For dogs, that could be everything from their resilience to stress to their propensity to chase squirrels. Guiding Eyes has already harnessed EBVs to reduce the incidence of hip and elbow dysplasia in their dogs, which can lead to limping and stiffness and are a major reason animals fail out of guide dog programs. They’ve also been able to cut down on other detrimental traits, including epilepsy and harness sensitivity.

Other schools like Canine Companions in Santa Rosa, California are using “cognitive test batteries”—scientifically rigorous mental challenges—that help predict which puppies are most likely to graduate from working dog programs, and which jobs they’ll be best suited for. Dogs that spend more time gazing into their trainer’s eyes, for example, or who quickly learn the best way to access a treat hidden in a tricky cylinder, may become more confident and clever working canines.

As I write in my latest feature for Science, the ultimate goal of all of this work is to help schools like Guiding Eyes and Canine Companions graduate more—and better—working dogs . That, in turn, could help ensure that more of these skilled canines end up in the hands of the people who desperately need them. As I completed the obstacle course still clutching the harness of my faithful companion, I already knew one who was going to transform the life of a lucky human.

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podcast

Building better working dogs, and watching a black hole form

By SARAH CRESPI, Kevin McLean, David Grimm | 12 February 2025

Et Cetera

Returned without review

In recent weeks, students seeking NSF’s Graduate Research Fellowship (GRF) have received brief and identical emails from NSF saying “your application did not meet the Eligibility/Compliance requirements and is being returned without review (RWR)”—a decision that is final and cannot be appealed. “In past years, [NSF] might have excluded a handful of applications that were clearly inappropriate,” said one former GRF program officer. “But this number is quite unusual. And it runs counter to the program’s goal of preparing the next generation of scientists by giving them a chance to have their ideas be subject to rigorous peer review.”