A startup called Reflect Orbital wants to launch thousands of mirror-bearing satellites to reflect sunlight onto Earth at night and "power solar farms after sunset, provide lighting for rescue workers and illuminate city streets, among other things," reports the New York Times. From the report: It is an idea seemingly out of a sci-fi movie, but the company, Reflect Orbital of Hawthorne, Calif., could soon receive permission to launch its first prototype satellite with a 60-foot-wide mirror. The company has applied to the Federal Communications Commission, which issues the licenses needed to deploy satellites. If the F.C.C. approves, the test satellite could get a ride into orbit as soon as this summer. The F.C.C.'s public comment period on the application closes on Monday. "We're trying to build something that could replace fossil fuels and really power everything," Ben Nowack, Reflect Orbital's chief executive, said in an interview. The company has raised more than $28 million from investors.

[...] Reflect Orbital's first prototype, which will be roughly the size of a dorm fridge, is almost complete. Once in space, about 400 miles up, the test satellite would unfurl a square mirror nearly 60 feet wide. That would bounce sunlight to illuminate a circular patch about three miles wide on the Earth's surface. Someone looking up would see a dot in the sky about as bright as a full moon. Two more prototypes could follow within a year. By the end of 2028, Reflect Orbital hopes to launch 1,000 larger satellites, and 5,000 of them by 2030. The largest mirrors are planned to be nearly 180 feet wide, reflecting as much light as 100 full moons. The company said its goal was to deploy the full constellation of 50,000 satellites by 2035.

How much does it cost to order sunlight at night? Mr. Nowack said the company would charge about $5,000 an hour for the light of one mirror if a customer signed an annual contract for 1,000 hours or more. Lighting for one-time events and emergencies, which might require numerous satellites and more effort to coordinate, would be more expensive. For solar farms, he envisions splitting revenue from the electricity generated by the additional hours of light.

After decades of searching for extraterrestrial intelligence, the nonprofit SETI Foundation has an announcement. "A new study by researchers at the SETI Institute suggests stellar 'space weather' could make radio signals from extraterrestrial intelligence harder to detect." Stellar activity and plasma turbulence near a transmitting planet can broaden an otherwise ultra-narrow signal, spreading its power across more frequencies and making it more difficult to detect in traditional narrowband searches. For decades, many SETI experiments have focused on identifying spikes in frequency — signals unlikely to be produced by natural astrophysical processes. But the new research highlights an overlooked complication: even if an extraterrestrial transmitter produces a perfectly narrow signal, it may not remain narrow by the time it leaves its home system... "If a signal gets broadened by its own star's environment, it can slip below our detection thresholds, even if it's there, potentially helping explain some of the radio silence we've seen in technosignature searches," said Dr. Vishal Gajjar, Astronomer at the SETI Institute and lead author of the paper.
The researchers created "a practical framework for estimating how much broadening could occur for different types of stars" — and accounting for space weather — by "using radio transmissions from spacecraft in our own solar system, then extrapolated to other stellar environments."

The study's co-author (a SETI Institute research assistant) suggests this coud lead to better-targetted SETI searches. (M-dwarf stars — about 75% of stars in the Milky Way — actually have the highest likelihood that narrowband signals would get broadened before leaving their system...)

Colliding black holes were detected through spacetime ripples for the first time in 2015 by the Laser Interferometer Gravitational-Wave Observatory (LIGO), notes Space.com: Since then, LIGO and its partner gravitational wave detectors Virgo in Italy and KAGRA (Kamioka Gravitational Wave Detector) in Japan have detected a multitude of gravitational waves from colliding black holes, merging neutron stars, and even the odd "mixed merger" between a black hole and a neutron star... During the first three observing runs of LIGO, Virgo and KAGRA, scientists had only "heard" 90 potential gravitational wave sources.
But now they've published new data from the LIGO-Virgo-KAGRA (LVK) Collaboration that includes 128 more gravitatational wave sources — some incredibly distant: [Gravitational-Wave Transient Catalog-4.0, or GWTC-4] was collected during the fourth observational run of these gravitational wave detectors, which was conducted between May 2023 and Jan. 2024... Excitingly, GWTC-4 could technically have been even larger, as around 170 other gravitational wave detections made by LIGO, Virgo and KAGRA haven't yet made their way into the catalog.

One aspect of GWTC-4 that really stands out is the variety of events that created these signals. Within this catalog are gravitational waves from mergers between the heaviest black hole binaries yet, each about 130 times as massive as the sun, lopsided mergers between black holes with seriously mismatched masses, and black holes that are spinning at incredible speeds of around 40% the speed of light. In these cases, scientists think the extreme characteristics of the black holes involved in these mergers are the result of prior collisions, providing evidence of merger chains that explain how some black holes grow to masses billions of times that of the sun... GWTC-4 also includes two new mixed mergers involving black holes and neutron stars.

[LVK member Daniel Williams, of the University of Glasgow in the U.K., said in their statement] "We are really pushing the edges, and are seeing things that are more massive, spinning faster, and are more astrophysically interesting and unusual." The catalog also demonstrates just how sensitive the LVK detectors have become. Some of the neutron star mergers occurred up to 1 billion light-years away, while some of the black hole mergers occurred up to 10 billion light-years away.
Einstein's theory of general relativity can be tested with these detections, and "So far, the theory is passing all our tests," says LVK member Aaron Zimmerman, of the University of Texas at Austin. "But we're also learning that we have to make even more accurate predictions to keep up with all the data the universe is giving us." And LVK member Rachel Gray, a lecturer at the University of Glasgow, says "every merging black hole gives us a measurement of the Hubble constant, and by combining all of the gravitational wave sources together, we can vastly improve how accurate this measurement is."

In short, says LVK member Lucy Thomas of the California Institute of Technology (Caltech), "Each new gravitational-wave detection allows us to unlock another piece of the universe's puzzle in ways we couldn't just a decade ago."

"A surgeon in London says he has performed the UK's first long-distance robotic operation," reports the BBC, "on a patient located 1,500 miles (2,400km) away..." Leading robotic urological surgeon Professor Prokar Dasgupta said it felt "almost as if I was there" as he carried out a prostate removal on [62-year-old] Paul Buxton... It is hoped that remote robotic surgery could spare future patients the "vast expense and inconvenience" of travelling for treatment, and help deliver better healthcare to people in more remote locations... Buxton had expected to be put on an NHS waiting list after receiving a shock prostate cancer diagnosis just after Christmas, but he "jumped at the chance" to be the first patient to undergo the treatment remotely as part of a trial. "A lot of people actually said to me: 'You're not going to do it, are you?'

"I thought, I'm giving something back here," he said...

The operation was performed from The London Clinic using a robot equipped with a 3D HD camera and four arms, all controlled through a console with a delay of only 0.06 seconds. The console in the UK was connected to the robot in Gibraltar via fibre-optic cables, with a backup 5G link. A team in Gibraltar remained on standby in case the connection failed, but it held throughout the procedure...

Dasgupta will perform the procedure again on 14 March, which will be live-streamed to 20,000 world-leading urological surgeons at the European Association of Urology congress. He added: "I think it is very, very exciting, the humanitarian benefit is going to be significant."
The U.K.'s National Health Service "is prioritising local robotic-assisted surgery," the article points out, "aiming for 500,000 robot-supported operations a year by 2035."

Thanks to Slashdot reader fjo3 for sharing the article.

NASA heralded a new study published Friday documenting a first for humanity — "the first time a human-made object has measurably altered the path of a celestial body around the Sun."

It was 2022's DART mission where NASA crashed a spacecraft into an asteroid — and the experiment "could have implications for protecting Earth from future asteroid strikes," writes ScienceNews: A spacecraft slowed the orbit of a pair of asteroids around the sun by more than 10 micrometers per second... Within a month, researchers showed that the impact shortened Dimorphos' 12-hour orbit by 32 minutes. Some of the rocks knocked off of Dimorphos fled the vicinity completely, escaping the gravitational influence of the Dimorphos-Didymos pair, says planetary defense researcher Rahil Makadia of the University of Illinois Urbana-Champaign. Those rocky runaways took some momentum away from the duo and changed their joint motion around the sun.

To figure out how much that motion was affected, astronomers watched the asteroids pass in front of distant stars, dimming some of the stars' light like a tiny eclipse. These blinks, called stellar occultations, can be visible from anywhere on Earth and are predictable in advance... Calculating how far off occultation timings were from predictions revealed that the asteroids' orbit around the sun was about 150 milliseconds slower than before the DART impact...

Didymos and Dimorphos are not a threat to Earth, Makadia says, and weren't before DART. But knowing how a deliberate impact changes one asteroid's orbit can help make defense plans against another, "in case we need to do a kinetic impact for real."
The researchers spent nearly two and a half years to collect 22 measurements of the asteroid's post-crash position, relying on amateur astronomers "to go out into the middle of nowhere and observe the necessary stellar occultations," acvcording to their paper. Planetary defense researcher even tells ScienceNews "There was an observer who drove two days each way into the Australian outback to get these measurements."

Long-time Slashdot reader fjo3 shared this report from Agence France-Presse: Japan has approved ground-breaking stem-cell treatments for Parkinson's and severe heart failure, one of the manufacturers and media reports said Friday, with the therapies expected to reach patients within months.

Pharmaceutical company Sumitomo Pharma said it received the green light for the manufacture and sale of Amchepry, its Parkinson's disease treatment that transplants stem cells into a patient's brain. Japan's health ministry also gave the go-ahead to ReHeart, heart muscle sheets developed by medical startup Cuorips that can help form new blood vessels and restore heart function, media reports said. The treatments could be on the market and rolled out to patients as early as this summer, reports said, citing the health ministry, becoming the world's first commercially available medical products using induced pluripotent stem cells...

In a statement, Sumitomo Pharma said it had obtained "conditional and time-limited approval" for the manufacture and marketing of Amchepry under a system which is reportedly designed to get these products to patients as quickly as possible. The approval is a kind of "provisional license", the Asahi newspaper said, after the safety and efficacy of the treatment was judged based on data from fewer patients than in ordinary clinical trials for drugs.

A trial led by Kyoto University researchers indicated that the company's treatment was safe and successful in improving symptoms. The study involved seven Parkinson's patients aged between 50 and 69, with each receiving a total of either five million or 10 million cells implanted on both sides of the brain... The patients were monitored for two years and no major adverse effects were found, the study said. Four patients showed improvements in symptoms.
The article notes that "Worldwide, about 10 million people have the illness, according to the Parkinson's Foundation," while also notes that today's current therapies "improve symptoms without slowing or halting the disease progression..."

Astronomers have spotted a galaxy they believe is made of 99.9% dark matter, reports CNN — and it's so faint, it's almost invisible: CDG-2, which is about 300 million light-years from Earth, appears to be so rich in dark matter that it could belong to a hypothesized subset of low surface brightness galaxies called "dark galaxies," which are believed to contain few or no stars.... [Post-doctoral astrophysics/statistics fellow Dayi Li at the University of Toronto was lead author on a study about the discovery, and tells CNN] There is no strict definition of dark galaxies... but their existence is predicted by dark matter theories and cosmological simulations. "Where exactly do we draw the line in terms of how many stars they should have is still ambiguous, because not everything in astronomy is as clear-cut as we like," he said. "To be technically correct, CDG-2 is an almost-dark galaxy. But the importance of CDG-2 is that it nudges us much closer to getting to that truly dark regime, while previously we did not think a galaxy this faint could exist."

To observe CDG-2, the researchers used data from three telescopes — Hubble, the European Space Agency's Euclid space observatory and the Subaru Telescope in Hawaii — along with a novel approach that involved looking for objects called globular clusters. "These are very tight, spherical groupings of very olds stars, basically the relics of the first generation of star formation," Li said. Globular clusters are bright even if the surrounding galaxy is not, and previous observations have shown a relationship between them and the presence of dark matter in a galaxy, Li added. Because CDG-2 appears to have very few stars, there must be something else providing the mass that the clusters need to hold themselves together. Li and his colleagues assume that the source of the mass is dark matter.

The researchers found a set of four globular clusters in the Perseus Cluster, a group of thousands of galaxies immersed in a cloud of gas and one of the most massive objects in the universe. Further observations revealed a glow or halo around the globular clusters, suggesting the presence of a galaxy... Astronomers believe, Li explained, that after the formation of the clusters early in the galaxy's existence, larger surrounding galaxies stripped it of the hydrogen gas required to make more individual stars like our sun. "The material that this galaxy needed to continue to form stars was no longer there, so it was left with basically just a dark matter halo and the four globular clusters." The process, he added, would leave behind a skeleton or ghost of "a galaxy that pretty much just failed." As a result of this formation mechanism, the galaxy only has 0.005% of the brightness of our own galaxy, Li said...

Studying potential dark galaxies is important because they provide nearly pristine views of the behavior of dark matter, according to Neal Dalal, a researcher at the Perimeter Institute for Theoretical Physics in Waterloo, Ontario, Canada, who was not involved with the study.
Robert Minchin, an astronomer at New Mexico's National Radio Astronomy Observatory, told CNN that "it seems likely that other very dark galaxies will be found by this method in the future."

Ancient Slashdot reader alanw shares a report from the European Space Agency (ESA): Last year, an approximately 60 meter near-Earth object captured global attention. For a brief period, asteroid 2024 YR4 became the most dangerous asteroid discovered in the last 20 years. While an Earth impact was soon ruled out, the asteroid faded from view with a lingering 4% chance of striking the Moon on 22 December 2032. Now, that risk has been eliminated. Astronomers have confirmed that 2024 YR4 will not impact the Moon using new observations made by the Near-Infrared Camera (NIRCam) on the NASA/ESA/CSA James Webb Space Telescope. Instead, it will safely pass the Moon at a distance of more than 20 000 km.

BrianFagioli shares a report from NERDS.xyz: An international team of scientists has done something chemistry has never seen before. IBM, working alongside researchers from the University of Manchester, Oxford University, ETH Zurich, EPFL, and the University of Regensburg, has created and characterized a molecule whose electrons travel through its structure in a corkscrew-like pattern, fundamentally altering its chemical behavior. The findings were published today in Science. The molecule, known as C13Cl2, is the first experimental observation of what scientists call a half-Mobius electronic topology in a single molecule. To the researchers' knowledge, nothing like it has ever been synthesized, observed, or even formally predicted. And proving why it behaves the way it does required something equally extraordinary -- a quantum computer.

The whole thing started at IBM, where the molecule was assembled atom by atom from a custom precursor synthesized at Oxford. Working under ultra-high vacuum at near-absolute-zero temperatures, researchers used precisely calibrated voltage pulses to remove individual atoms one at a time. The result is an electronic structure that undergoes a 90-degree twist with each circuit through the molecule, requiring four complete loops to return to its starting phase. That is a topological property that has no counterpart anywhere in chemistry's existing record. What makes it even more interesting to folks who follow materials science is that this topology can be switched. The molecule can move reversibly between clockwise-twisted, counterclockwise-twisted, and untwisted states. That means electronic topology is not just a curiosity to be stumbled upon in nature -- it can be deliberately engineered. That is a big deal.

The quantum computing angle here is not just a supporting role. Electrons within C13Cl2 interact in deeply entangled ways, each influencing the others simultaneously. Modeling that requires tracking every possible configuration of those interactions at once -- something that causes computational demands to grow exponentially and can quickly overwhelm classical machines. A decade ago, researchers could exactly model 16 electrons classically. Today that number has crept to 18. Using IBM's quantum computer, the team was able to explore 32 electrons. Quantum computers can represent these systems directly rather than approximate them, because they operate according to the same quantum mechanical laws that govern electrons in molecules. In this case, that capability helped reveal helical molecular orbitals for electron attachment -- a fingerprint of the half-Mobius topology -- and exposed the mechanism behind the unusual structure: a helical pseudo-Jahn-Teller effect.

A recently-revised Senate authorization bill (PDF), co-sponsored by Senate Commerce Committee Chair Ted Cruz, would extend the International Space Station's lifespan from 2030 to 2032 while pushing NASA to accelerate plans for commercial space stations to replace it. Ars Technica's Eric Berger reports: Regarding NASA's support for the development of commercial space stations, the bill mandates the following, within specified periods, of passage of the law:

- Within 60 days, publicly release the requirements for commercial space stations in low-Earth orbit
- Within 90 days, release the final "request for proposals" to solicit industry responses
- Within 180 days, enter into contracts with "two or more" commercial providers for such stations

Cruz is trying to inject urgency into NASA as several private companies -- including Axiom Space, Blue Origin, Vast, and Voyager -- are finalizing designs for space stations. All have expressed a desire for clarity from NASA on how long the space agency would like its astronauts to stay on board, the types of scientific equipment needed, and much more. These are known as "requirements" in NASA parlance.

[...] Cruz and other senators on the committee appear to share those concerns, as their legislation extends the International Space Station's lifespan from 2030 to 2032 (an extension must still be approved by international partners, including Russia). Moreover, the authorization bill states, "The Administrator shall not initiate the de-orbit of the ISS until the date on which a commercial low-Earth orbit destination has reached an initial operational capability." With this legislation, the U.S. Senate is making clear that it views a permanent human presence in low-Earth orbit as a high priority. This version of the authorization legislation must still be passed by the full Senate and work its way through the House of Representatives.

NASA is eyeing an April launch window for the upcoming Artemis II mission after it repaired a helium-flow issue on the Space Launch System upper stage rocket. "Work on the rocket and spacecraft will continue in the coming weeks as NASA prepares for rolling the rocket out to the launch pad again later this month ahead of a potential launch in April," NASA wrote in an update on Tuesday. Space.com reports: The repair work occurred inside the huge Vehicle Assembly Building (VAB) at NASA's Kennedy Space Center (KSC) in Florida. Artemis 2's SLS and Orion crew capsule have been in the VAB since Feb. 25, when they rolled back to the hangar from KSC's Launch Pad 39B. Just a few days earlier, the Artemis 2 stack successfully completed a wet dress rehearsal, a two-day-long practice run of the procedures leading up to launch.

In the wake of that test, however, NASA noticed an interruption in helium flow in the SLS' upper stage. That was a significant issue, because helium pressurizes the rocket's propellant tanks. Rollback was the only option, as the affected area in the upper stage was not accessible at the pad. The problem took a potential March launch out of play for Artemis 2, which will send four astronauts on a roughly 10-day flight around the moon. It will be the first crewed flight to the lunar neighborhood since Apollo 17 in 1972.

The next Artemis 2 launch window opens in April, with liftoff opportunities on April 1, April 3-6 and April 30. And those options apparently remain in play, thanks to recent work in the VAB. That work centered on a seal in an interface through which helium flows from ground equipment into the SLS upper stage. That seal was obstructing the interface, which is known as a quick disconnect.

alternative_right shares a report from ScienceAlert: According to a study of 38 adult human brains donated to science, superagers -- people who retain exceptional memory as they age -- have roughly twice as many immature neurons as their peers who age more typically. Moreover, people with Alzheimer's disease show a marked reduction in neurogenesis compared to a normal baseline. [...]

Led by researchers at the University of Illinois Chicago, the team set out to examine a variety of postmortem hippocampal tissue samples to see if they could identify markers of neurogenesis -- and if different groups had any notable differences. The brain samples were donated from five groups: eight healthy young adults, aged between 20 and 40; eight healthy agers, aged between 60 and 93; six superagers, aged between 86 and 100; six individuals with preclinical Alzheimer's pathology, aged between 80 and 94; and 10 individuals with an Alzheimer's diagnosis, aged between 70 and 93. The young healthy adult brain tissue was first analyzed to establish the neurogenesis pathways in the adult brain. Then, they analyzed 355,997 individual cell nuclei isolated from the hippocampus, searching for three different stages of cell development: Stem cells, which can develop into neurons; neuroblasts, which are stem cells in the process of that development; and immature neurons, on the verge of functionality. The results were striking.

"Superagers had twice the neurogenesis of the other healthy older adults," [says neuroscientist Orly Lazarov of the University of Illinois Chicago]. "Something in their brains enables them to maintain a superior memory. I believe hippocampal neurogenesis is the secret ingredient, and the data support that." That's an interesting result on its own, but the data from the individuals with preclinical Alzheimer's pathology and Alzheimer's diagnoses is where the real meat of the study sits. In the preclinical group, subtle molecular changes hinted that the system supporting new neuron growth was beginning to falter. In the Alzheimer's group, a clear drop in immature neurons was evident. A genetic analysis of the nuclei also showed that superager neural cells have increased gene activity linked to stronger synaptic connections, greater plasticity, and brain-derived neurotrophic factor, a critical protein for neural survival, growth, and maintenance. Taken together, these three things can be interpreted as resilience. The research has been published in the journal Nature.

"Saturn and some of its 274 moons are pretty weird," writes Smithsonian magazine: [Saturn moon] Titan has strangely few impact craters, Hyperion is tiny and misshapen, and Iapetus has a tilted orbit. What's more, planets tend to wobble along their rotational axes as they spin, like an off-kilter spinning top in the moments before it topples over. Formally called precession, scientists have long thought that Saturn's wobble rate should match Neptune's because they're probably gravitationally linked. However, data from NASA's Cassini spacecraft, which studied the ringed planet from 2004 to 2017, revealed that Saturn's precession rate is slightly speedier than Neptune's.

In 2022, some researchers suggested that the destruction of a hypothetical moon, called Chrysalis, around 160 million years ago may have knocked Saturn out of sync and formed the pieces that became the planet's rings. But this work implied that Chrysalis probably would've crashed into Titan, posing a major problem, study co-author Matija Äuk, an astronomer at the SETI Institute, tells New Scientist's Leah Crane. In that case, Chrysalis' debris couldn't have become the rings, he says.

So, Äuk and his colleagues used computer simulations to investigate what would happen if Chrysalis did smack into Titan. If that happened around 400 million years ago, they found, the crash would've wiped away Titan's craters and made its orbit more elliptical. The altered path may have slowly pushed the trajectories of other moons, which then scraped against one another and left chunks of ice and rock that now make up Saturn's rings. The timing seems to align with the rings' estimated age of roughly 100 million years. Additionally, one piece of kicked-up debris may have formed the weird moon Hyperion, which may have subsequently tilted the orbit of the moon Iapetus, according to the analysis. The scenario could also resolve Saturn's unexpected wobble, which is currently "a little bit too fast," Äuk tells Jacopo Prisco at CNN.
The study has been accepted for publication in the Planetary Science Journal, and is already available on the preprint server arXiv.

In a library in Florence, Italy, historian Ivan Malara noticed handwritten notes on a book printed in the 1500s — and recognized the handwriting as Galileo's. The finding "promises new insights into one of the most famous ideological transitions in the history of science," writes Science magazine — since the book Galileo annotated was a reprint of Ptolemy's second-century work arguing that the earth was the center of the universe. Galileo's notes, perhaps written around 1590, or roughly 2 decades before his groundbreaking telescope observations of the Moon and Jupiter, reveal someone who both revered and critically dissected Ptolemy's work. And they imply, Malara argues, that Galileo ultimately broke with Ptolemy's cosmos because his mastery of the traditional paradigm's reasoning convinced him that a heliocentric [sun-centered] system would better fulfill Ptolemy's own mathematical logic.

There's already 5,000 sensors embedded in Antarctica's ice to look for evidence of neutrinos, reports the Washington Post. But in November scientists drilled six new holes at least a mile and a half deep and installed cables with hundreds more light detectors — an upgrade to the massive 15-year-old IceCube Neutrino Observatory to detect the charged particles produced by lower-energy neutrinos interacting with matter: When they do, the neutrinos produce charged particles that travel through the ice at nearly the speed of light, creating a blue glow called Cherenkov radiation... "Within the first couple years, we should be making much better measurements," [said Erin O'Sullivan, an associate professor of physics at Uppsala University in Sweden and a spokesperson for the project.] "There's hope to expand the detector, by an order of magnitude in volume, so the important thing there is we're not just seeing a few neutrino point sources, but we're starting to be a true telescope. ... That's really the dream."
The scientists spent seven years planning the upgrade, according to the article. "To drill holes a mile and a half deep takes about 30 hours, and 18 more hours to return to the surface," the article points out. "Then, the race begins because almost immediately, the hole starts to shrink as the water refreezes." ("If it takes too much time, the principal investigator says, "the instruments don't fit in anymore!")