Science – Page 6

George R.R. Martin has co-authored a physics paper

Science / Tim Belzer / January 23, 2025

They also suggest the existence of “cryptos”: Jokers and Aces with mutations that are largely unobservable, such as producing ultraviolet racing stripes on someone’s heart or imbuing “a resident of Iowa with the power of line-of-sight telepathic communication with narwhals. The first individual would be unaware of their Jokerism; the second would be an Ace but never known it.” (One might argue that communicating with narwhals might make one a Deuce.)

In the end, Tregillis and Martin came up with three ground rules: (1) cryptos exist, but how many of them exist is “unknown and unknowable”; (2) observable card turns would be distributed according to the 90:9:1 rule; and (3) viral outcomes would be determined by a multivariate probability distribution.

The resulting proposed model assumes two apparently random variables: severity of the transformation—i.e., how much the virus changes a person, either in the severity of a Joker’s deformation or the potency of an Ace’s superpower—and a mixing angle to address the existence of Joker-Aces. “Card turns that land sufficiently close to one axis will subjectively present as Aces, while otherwise they will present as Jokers or Joker-Aces,” the authors wrote.

The derived formula is one that takes into account the many different ways a given system can evolve (aka a Langrangian formulation). “We translated the abstract problem of Wild Card viral outcomes into a simple, concrete dynamical system. The time-averaged behavior of this system generates the statistical distribution of outcomes,” said Tregillis.

Tregillis acknowledges that this might not be a good exercise for the beginning physics student, given that it involves multiple steps and covers many concepts that younger students might not fully comprehend. Nor does he suggest adding it to the core curriculum. Instead, he recommends it for senior honors seminars to encourage students to explore an open-ended research question.

DOI: American Journal of Physics, 2025. 10.1119/5.0228859 (About DOIs).

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Fast radio burst in long-dead galaxy puzzles astronomers

astronomy, astrophysics, fast radio bursts, magnetars, Science / Rejus Almole / January 22, 2025

A surprising source

FRBs are of particular interest because they can be used as probes to study the large-scale structure of the universe. That’s why Calvin Leung, a postdoc at the University of California, Berkeley, was so excited to crunch data from Canada’s CHIME instrument (Canadian Hydrogen Intensity Mapping Experiment). CHIME was built for other observations but is sensitive to many of the wavelengths that make up an FRB. Unlike most radio telescopes, which focus on small points in the sky, CHIME scans a huge area, allowing it to pick out FRBs even though they almost never happen in the same place twice.

Leung was able to combine data from several different telescopes to narrow down the likely position of a repeating FRB, first detected in February 2024, located in the constellation Ursa Minor. When he and his CHIME collaborators further refined the accuracy of the location by averaging many bursts from the FRB, they discovered that this FRB originated on the outskirts of a long-dead distant galaxy. That throws a wrench into the magnetar hypothesis because why would a dead galaxy in which no new stars are forming host a magnetar?

It’s the first time an FRB has been found in such a location, and it’s also the furthest away from its galaxy. CHIME currently has two online outrigger radio arrays in place—companion telescopes to the original CHIME radio array in British Columbia. A third array comes online this week in Northern California, and according to Leung, it should enable astronomers to pinpoint FRB sources much more accurately—including this one. Data has already been incorporated from an outrigger in West Virginia, confirming the published position with a 20-times improvement in precision.

“This result challenges existing theories that tie FRB origins to phenomena in star-forming galaxies,” said co-author Vishwangi Shah, a graduate student at McGill University. “The source could be in a globular cluster, a dense region of old, dead stars outside the galaxy. If confirmed, it would make FRB 20240209A only the second FRB linked to a globular cluster.”

V. Shah et al., Astrophysical Journal Letters, 2025. DOI: 10.3847/2041-8213/ad9ddc (About DOIs).

T. Eftekhari et al., Astrophysical Journal Letters, 2025. DOI: 10.3847/2041-8213/ad9de2 (About DOIs).

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How to get a perfect salt ring deposit in your pasta pot

everyday physics, fluid dynamics, Physics, Science, sedimentation / Rejus Almole / January 21, 2025

Deposit morphologies for a settling particle. When increasing either the injection volume or the settling height, the deposit radius increases. Credit: M. Souzy et al., 2025

They used spherical borosilicate glass beads of varying diameters to represent the grains of salt and loaded different fixed volumes of beads into cylindrical tubes. Then they slid open the tube’s bottom to release the beads, capturing how they fell and settled with a Nikon D300 camera placed at the top of the tank. The tank was illuminated from below by a uniform LED light screen and diffuser to get an even background.

The physicists found that gravity will pull a single particle to the bottom of the tank, creating a small wake drag that affects the flow of water around it. That perturbation becomes much more complicated when many large particles are released at once, each with its own wake that affects its neighbors. So, the falling particles start to shift horizontally, distributing the falling particles in an expanding circular pattern.

Particles released from a smaller height fall faster and form a pattern with a clean central region. Those released from a greater height take longer to fall to the bottom, and the cloud of particles expands radially until the particles are far enough apart not to be influenced by the wakes of neighboring particles such that they no longer form a cloud. In that case, you end up with a homogeneous salt ring deposit.

“These are the main physical ingredients, and despite its apparent simplicity, this phenomenon encompasses a wide range of physical concepts such as sedimentation, non-creeping flow, long-range interactions between multiple bodies, and wake entrainment,” said Souzy. “Things get even more interesting once you realize larger particles are more radially shifted than small ones, which means you can sort particles by size just by dropping them into a water tank. It was a great overall experience, because we soon realized our simple observation of daily life conceals a rich variety of physical mechanisms.”

Those phenomena are just as relevant outside the kitchen, according to the authors, most notably in such geophysical and industrial contexts as “the discharge of dredged materials and industrial waste into rivers lakes and oceans,” they wrote. “In scenarios involving contaminated waste, comprehending the behavior of both the solid waste and the interacting fluid is crucial.”

Physics of Fluids, 2025. DOI: 10.1063/5.0239386 (About DOIs).

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Edge of Mars’ great dichotomy eroded back by hundreds of kilometers

erosion, geology, Mars, oceans, planetary science, Science / Paul Patrick / January 20, 2025

A shoreline transformed?

The huge area covered by these mounds gives a sense of just how significant this erosion was. “The dichotomy boundary has receded several hundred kilometres,” the researchers note. “Nearly all intervening material—approximately 57,000 cubic kilometers over an area of 284,000 square kilometers west of Ares Vallis alone—has been removed, leaving only remnant mounds.”

Based on the distribution of the different clays, the team argues that their water-driven formation took place before the erosion of the material. This would indicate that water-rock interactions were going on over a very wide region early in the history of Mars, which likely required an extensive hydrological cycle on the red planet. As the researchers note, a nearby ocean would have improved the chances of exposing this region to water, but the exposure could also have been due to processes like melting at the base of an ice cap.

Complicating matters further, many of the mounds top out below one proposed shoreline of the northern ocean and above a second. It’s possible that a receding ocean could have contributed to their erosion. But, at the same time, some of the features of a proposed shoreline now appear to have been caused by the general erosion of the original plateau, and may not be associated with an ocean at all.

Overall, the new results provide mixed evidence for the presence of a Martian ocean. They clearly show an active water cycle and erosion on a massive scale, which are both consistent with having a lot of water around. At the same time, however, the water exposure the mesas and buttes have experienced needn’t have come through their being submerged by said ocean and, given their elevation, might best be explained through some other process.

Nature Geoscience, 2019. DOI: 10.1038/s41561-024-01634-8 (About DOIs).

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Robotic hand helps pianists overcome “ceiling effect”

robotic exoskeleton, robotics, Science / Paul Patrick / January 20, 2025

Fast and complex multi-finger movements generated by the hand exoskeleton. Credit: Shinichi Furuya

When it comes to fine-tuned motor skills like playing the piano, practice, they say, makes perfect. But expert musicians often experience a “ceiling effect,” in which their skill level plateaus after extensive training. Passive training using a robotic exoskeleton hand could help pianists overcome that ceiling effect, according to a paper published in the journal Science Robotics.

“I’m a pianist, but I [injured] my hand because of overpracticing,” coauthor Shinichi Furuya of Kabushiki Keisha Sony Computer Science Kenkyujo told New Scientist. “I was suffering from this dilemma, between overpracticing and the prevention of the injury, so then I thought, I have to think about some way to improve my skills without practicing.” Recalling that his former teachers used to place their hands over his to show him how to play more advanced pieces, he wondered if he could achieve the same effect with a robotic hand.

So Furuya et al. used a custom-made exoskeleton robot hand capable of moving individual fingers on the right hand independently, flexing and extending the joints as needed. Per the authors, prior studies with robotic exoskeletons focused on simpler movements, such as assisting in the movement of limbs stabilizing body posture, or helping grasp objects. That sets the custom robotic hand used in these latest experiments apart from those used for haptics in virtual environments.

A helping robot hand

A total of 118 pianists participated in three different experiments. In the first, 30 pianists performed a designated “chord trill” motor task with the piano at home every day for two weeks: first simultaneously striking D and F keys with the right index and ring fingers, then striking the E and G keys with the right middle and little fingers. “We used this task because it has been widely recognized as technically challenging to play quickly and accurately,” the authors explained. It appears in such classical pieces as Chopin’s Etude Op. 25. No. 6, Maurice Ravel’s “Ondine,” and the first movement of Beethoven’s Piano Sonata No. 3.

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Sleeping pills stop the brain’s system for cleaning out waste

Biology, brain, Features, neurobiology, nREM sleep, Science, sleeping pills / Mike M. / January 20, 2025

Cleanup on aisle cerebellum

A specialized system sends pulses of pressure through the fluids in our brain.

Our bodies rely on their lymphatic system to drain excessive fluids and remove waste from tissues, feeding those back into the blood stream. It’s a complex yet efficient cleaning mechanism that works in every organ except the brain. “When cells are active, they produce waste metabolites, and this also happens in the brain. Since there are no lymphatic vessels in the brain, the question was what was it that cleaned the brain,” Natalie Hauglund, a neuroscientist at Oxford University who led a recent study on the brain-clearing mechanism, told Ars.

Earlier studies done mostly on mice discovered that the brain had a system that flushed its tissues with cerebrospinal fluid, which carried away waste products in a process called glymphatic clearance. “Scientists noticed that this only happened during sleep, but it was unknown what it was about sleep that initiated this cleaning process,” Hauglund explains.

Her study found the glymphatic clearance was mediated by a hormone called norepinephrine and happened almost exclusively during the NREM sleep phase. But it only worked when sleep was natural. Anesthesia and sleeping pills shut this process down nearly completely.

Taking it slowly

The glymphatic system in the brain was discovered back in 2013 by Dr. Maiken Nedergaard, a Danish neuroscientist and a coauthor of Hauglund’s paper. Since then, there have been numerous studies aimed at figuring out how it worked, but most of them had one problem: they were done on anesthetized mice.

“What makes anesthesia useful is that you can have a very controlled setting,” Hauglund says.

Most brain imaging techniques require a subject, an animal or a human, to be still. In mouse experiments, that meant immobilizing their heads so the research team could get clear scans. “But anesthesia also shuts down some of the mechanisms in the brain,” Hauglund argues.

So, her team designed a study to see how the brain-clearing mechanism works in mice that could move freely in their cages and sleep naturally whenever they felt like it. “It turned out that with the glymphatic system, we didn’t really see the full picture when we used anesthesia,” Hauglund says.

Looking into the brain of a mouse that runs around and wiggles during sleep, though, wasn’t easy. The team pulled it off by using a technique called flow fiber photometry which works by imaging fluids tagged with fluorescent markers using a probe implanted in the brain. So, the mice got the optical fibers implanted in their brains. Once that was done, the team put fluorescent tags in the mice’s blood, cerebrospinal fluid, and on the norepinephrine hormone. “Fluorescent molecules in the cerebrospinal fluid had one wavelength, blood had another wavelength, and norepinephrine had yet another wavelength,” Hauglund says.

This way, her team could get a fairly precise idea about the brain fluid dynamics when mice were awake and asleep. And it turned out that the glymphatic system basically turned brain tissues into a slowly moving pump.

Pumping up

“Norepinephrine is released from a small area of the brain in the brain stem,” Hauglund says. “It is mainly known as a response to stressful situations. For example, in fight or flight scenarios, you see norepinephrine levels increasing.” Its main effect is causing blood vessels to contract. Still, in more recent research, people found out that during sleep, norepinephrine is released in slow waves that roll over the brain roughly once a minute. This oscillatory norepinephrine release proved crucial to the operation of the glymphatic system.

“When we used the flow fiber photometry method to look into the brains of mice, we saw these slow waves of norepinephrine, but we also saw how it works in synchrony with fluctuation in the blood volume,” Hauglund says.

Every time the norepinephrine level went up, it caused the contraction of the blood vessels in the brain, and the blood volume went down. At the same time, the contraction increased the volume of the perivascular spaces around the blood vessels, which were immediately filled with the cerebrospinal fluid.

When the norepinephrine level went down, the process worked in reverse: the blood vessels dilated, letting the blood in and pushing the cerebrospinal fluid out. “What we found was that norepinephrine worked a little bit like a conductor of an orchestra and makes the blood and cerebrospinal fluid move in synchrony in these slow waves,” Hauglund says.

And because the study was designed to monitor this process in freely moving, undisturbed mice, the team learned exactly when all this was going on. When mice were awake, the norepinephrine levels were much higher but relatively steady. The team observed the opposite during the REM sleep phase, where the norepinephrine levels were consistently low. The oscillatory behavior was present exclusively during the NREM sleep phase.

So, the team wanted to check how the glymphatic clearance would work when they gave the mice zolpidem, a sleeping drug that had been proven to increase NREM sleep time. In theory, zolpidem should have boosted brain-clearing. But it turned it off instead.

Non-sleeping pills

“When we looked at the mice after giving them zolpidem, we saw they all fell asleep very quickly. That was expected—we take zolpidem because it makes it easier for us to sleep,” Hauglund says. “But then we saw those slow fluctuations in norepinephrine, blood volume, and cerebrospinal fluid almost completely stopped.”

No fluctuations meant the glymphatic system didn’t remove any waste. This was a serious issue, because one of the cellular waste products it is supposed to remove is amyloid beta, found in the brains of patients suffering from Alzheimer’s disease.

Hauglund speculates it could be possible zolpidem induces a state very similar to sleep but at the same time it shuts down important processes that happen during sleep. While heavy zolpidem use has been associated with increased risk of the Alzheimer disease, it is not clear if this increased risk was there because the drug was inhibiting oscillatory norepinephrine release in the brain. To better understand this, Hauglund wants to get a closer look into how the glymphatic system works in humans.

“We know we have the same wave-like fluid dynamics in the brain, so this could also drive the brain clearance in humans,” Haugland told Ars. “Still, it’s very hard to look at norepinephrine in the human brain because we need an invasive technique to get to the tissue.”

But she said norepinephrine levels in people can be estimated based on indirect clues. One of them is pupil dilation and contraction, which work in in synchrony with the norepinephrine levels. Another other clue may lay in microarousals—very brief, imperceivable awakenings which, Hauglund thinks, can be correlated with the brain clearing mechanism. “I am currently interested in this phenomenon […]. Right now we have no idea why microarousals are there or what function they have” Hauglund says.

But the last step she has on her roadmap is making better sleeping pills. “We need sleeping drugs that don’t have this inhibitory effect on the norepinephrine waves. If we can have a sleeping pill that helps people sleep without disrupting their sleep at the same time it will be very important,” Hauglund concludes.

Cell, 2025. DOI: 10.1016/j.cell.2024.11.027

Jacek Krywko is a freelance science and technology writer who covers space exploration, artificial intelligence research, computer science, and all sorts of engineering wizardry.

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Peeing is contagious among chimps

animal behavior, animals, Biology, chimpanzees, Science, zoology / Rejus Almole / January 20, 2025

Those results supported the initial hypothesis that chimps tended to urinate in sync rather than randomly. Further analysis showed that the closer a chimp was to another peeing chimp, the more likely the probability of that chimp peeing as well—evidence of social contagion. Finally, Onishi et al. wanted to explore whether social relationships (like socially close pairs, evidenced by mutual grooming and similar behaviors) influenced contagious urination. The only social factor that proved relevant was dominance, with less-dominant chimps being more prone to contagious urination.

There may still be other factors influencing the behavior, and more experimental research is needed on potential sensory cues and social triggers in order to identify possible underlying mechanisms for the phenomenon. Furthermore, this study was conducted with a captive chimp population; to better understand potential evolutionary roots, there should be research on wild chimp populations, looking at possible links between contagious urination and factors like ranging patterns, territory use, and so forth.

“This was an unexpected and fascinating result, as it opens up multiple possibilities for interpretation,” said coauthor Shinya Yamamoto, also of Kyoto University. “For instance, it could reflect hidden leadership in synchronizing group activities, the reinforcement of social bonds, or attention bias among lower-ranking individuals. These findings raise intriguing questions about the social functions of this behavior.”

DOI: Current Biology, 2025. 10.1016/j.cub.2024.11.052 (About DOIs).

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Life is thriving in the subsurface depths of Earth

Biology, Ecology, life, Science / Kris Guyer / January 20, 2025

Nitrospirota is an archaeal phylum that’s particularly common in the terrestrial subsurface. Some species of nitrospirota are capable of oxidizing ammonia, while others can reduce it to nitrite, which is used by phytoplankton and also defends against pathogens in the human stomach, mouth, and skin.

Proteobacteria is a bacterial phylum that’s especially abundant in the terrestrial and marine subsurface. Some proteobacteria live in deep ocean trenches, and oxidize carbon monoxide (which contributes to global warming and depletes ozone). Bacteria also common in the marine subsurface include Desulfobacteria and Methylomirabilota. Desulfobacteria reduce sulfates, and other sulfate-reducing bacterias have already shown they can be used to help clean up contaminated soil. Methylomirabilota help control methane levels in the atmosphere by oxidizing methane.

Something unexpected that caught Ruff’s attention was how total diversity went up with depth. This was surprising because less energy is available at deeper levels of the subsurface. For archaea, diversity went up with the increase in depth in terrestrial environments but not marine environments. The same happened with bacteria, except in marine instead of terrestrial environments.

Much of what lies far below our feet still eludes us. Ruff suggests that single-cell microbes in even deeper, yet unexplored levels of the subsurface may have adapted to the absence of energy by slowing down their metabolisms so drastically that it could take decades, even centuries, for them to divide just once.

If there really are microbes that manage to live longer than humans with this survival tactic, it is possible similar species might be hiding on planets such as Mars, where the surface has long been blasted by radiation.

“Understanding deep life on Earth could be a model for discovering if there was life on Mars, and if it has survived,” Ruff said in a press release.

Maybe future technology could retrieve samples several kilometers below the Martian surface. Until then, keep digging.

Science Advances, 2024. DOI: 10.1126/sciadv.adq0645

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Has Trump changed the retirement plans for the country’s largest coal plants?

coal, coal power, Policy, power plant, Science, syndication / Paul Patrick / January 18, 2025

A growth in electricity demand is leading to talk of delayed closures.

A house is seen near the Gavin Power Plant in Cheshire, Ohio. Credit: Stephanie Keith/Getty Images

This article originally appeared on Inside Climate News, a nonprofit, non-partisan news organization that covers climate, energy, and the environment. Sign up for their newsletter here.

There is renewed talk of a coal power comeback in the United States, inspired by Donald Trump’s return to the presidency and forecasts of soaring electricity demand.

The evidence so far only shows that some plants are getting small extensions on their retirement dates. This means a slowdown in coal’s rate of decline, which is bad for the environment, but it does little to change the long-term trajectory for the domestic coal industry.

In October, I wrote about how five of the country’s 10 largest coal-fired power plants had retirement dates. Today, I’m revisiting the list, providing some updates and then taking a few steps back to look at US coal plants as a whole. Consider this the “before” picture that can be judged against the “after” in four years.

Some coal plant owners have already pushed back retirement timetables. The largest example, this one from just before the election, is the Gibson plant in Indiana, the second-largest coal plant in the country. It’s set to close in 2038 instead of 2035, following an announcement in October from the owner, Duke Energy.

But the changes do not constitute a coal comeback in this country. For that to happen, power companies would need to be building new plants to replace the many that are closing, and there is almost no development of new coal plants.

That said, there have been some changes since October.

As recently as a few months ago, Southern Co. was saying it intended to close Plant Bowen in Georgia by 2035 at the latest. Bowen is the largest coal plant in the country, with a summer capacity of 3,200 megawatts.

Southern has since said it may extend the plant’s life in response to forecasts of rising electricity demand. Chris Womack, Southern’s CEO, confirmed this possibility when speaking at a utility industry conference in November, saying that the plant may need to operate for longer than previously planned because of demand from data centers.

Southern has not yet made regulatory filings that spell out its plans, but this will likely occur in the next few weeks, according to a company spokesman.

In October, I reported that the Gavin plant in Ohio was likely to get a 2031 date to retire or switch to a different fuel once the plant’s pending sale was completed. The person who shared that information with me was involved with the plans and spoke on condition of anonymity because the sale was not final.

Since then, the prospective buyer of the plant has said in federal regulatory filings that it has no timetable for closing the plant or switching to a different fuel. The plant is changing hands as part of a larger deal between investment firms, with Lightstone Holdco selling to Energy Capital Partners, or ECP. Another company, coal exporter Javelin Global Commodities, is buying a minority share of the Gavin plant.

I went back to the person who told me about the 2031 retirement date. They said forecasts of rising electricity demand, as well as the election of Trump, have created enough uncertainty about power prices and regulations that it makes sense to not specify a date.

The 2031 timeline, and its abandonment, makes some sense once you understand that the Biden administration finalized power plant regulations last spring that gave coal plant operators an incentive to announce a retirement date: Plants closing before 2032 faced no new requirements. That incentive is likely to go away as Trump plans to roll back power plant pollution regulations.

Gavin’s sale is still pending. Several parties have filed objections to the transaction with the Federal Energy Regulatory Commission, arguing that the sellers have not been clear enough about their plans.

An ECP spokesman said the company has no comment beyond its filings.

Other than the changes to plans for Bowen and Gavin, the outlook has not shifted for the rest of the plants among the 10 largest. The Gibson and Rockport plants in Indiana still have retirement dates, as do Cumberland in Tennessee and Monroe in Michigan, according to the plants’ owners.

The Amos plant in West Virginia, Miller in Alabama, Scherer in Georgia, and Parish in Texas didn’t have retirement dates a few months ago, and they still don’t.

But the largest coal plants are only part of the story. Several dozen smaller plants are getting extensions of retirement plans, as Emma Foehringer Merchant reported last week for Floodlight News.

One example is the 1,157-megawatt Baldwin plant in Illinois, which was scheduled to close this year. Now the owner, Vistra Corp., has pushed back the retirement to 2027.

A few extra years of a coal plant is more of a stopgap than a long-term solution. When it comes to building new power plants to meet demand, developers are talking about natural gas, solar, nuclear, and other resources, but I have yet to see a substantial discussion of building a new coal plant.

In Alaska, Gov. Mike Dunleavy has said the state may build two coal plants to provide power in remote mining areas, as reported by Taylor Kuykendall of S&P Global Commodity Insights. Flatlands Energy, a Canadian company, has also talked about building a 400-megawatt coal plant in Alaska, as Nathaniel Herz reported for Alaska Beacon. These appear to be early-stage plans.

The lack of development activity underscores how coal power is fading in this country, and has been for a while.

Coal was used to generate 16 percent of US electricity in 2023, down by more than half from 2014. In that time, coal went from the country’s leading fuel for electricity to trailing natural gas, renewables, and nuclear. (These and all the figures that follow are from the US Energy Information Administration.)

The United States had about 176,000 megawatts of coal plant capacity as of October, down from about 300,000 megawatts in 2014.

The coal plants that do remain are being used less. In 2023, the average capacity factor for a coal plant was 42 percent. Capacity factor is a measure of how much electricity a plant has generated relative to the maximum possible if it was running all the time. In 2014, the average capacity factor was 61 percent.

Power companies are burning less coal because of the availability of less expensive alternatives, such as natural gas, wind, and solar, among others. The think tank Energy Innovation issued a report in 2023 finding that 99 percent of US coal-fired power plants cost more to operate than the cost of replacement with a combination of wind, solar, and batteries.

The Trump administration will arrive in Washington with promises to help fossil fuels. It could extend the lives of some coal plants by weakening environmental regulations, which may reduce the plants’ operational costs. It also could repeal or revise subsidies that help to reduce the costs of renewables and batteries, making those resources more expensive.

I don’t want to minimize the damage that could be caused by those policies. But even in extreme scenarios, it’s difficult to imagine investors wanting to spend billions of dollars to develop a new coal plant, much less a fleet of them.

Has Trump changed the retirement plans for the country’s largest coal plants? Read More »

Fire destroys Starship on its seventh test flight, raining debris from space

Commercial space, FAA, Features, launch, NASA, Science, Space, spacex, Starbase, starship / Tim Belzer / January 18, 2025

This launch debuted a more advanced, slightly taller version of Starship, known as Version 2 or Block 2, with larger propellant tanks, a new avionics system, and redesigned feed lines flowing methane and liquid oxygen propellants to the ship’s six Raptor engines. SpaceX officials did not say whether any of these changes might have caused the problem on Thursday’s launch.

SpaceX officials have repeatedly and carefully set expectations for each Starship test flight. They routinely refer to the rocket as experimental, and the primary focus of the rocket’s early demo missions is to gather data on the performance of the vehicle. What works, and what doesn’t work?

Still, the outcome of Thursday’s test flight is a clear disappointment for SpaceX. This was the seventh test flight of SpaceX’s enormous rocket and the first time Starship failed to complete its launch sequence since the second flight in November 2023. Until now, SpaceX has made steady progress, and each Starship flight has achieved more milestones than the one before.

On the first flight in April 2023, the rocket lost control a little more than two minutes after liftoff, and the ground-shaking power of the booster’s 33 engines shattered the concrete foundation beneath the launch pad. Seven months later, on Flight 2, the rocket made it eight minutes before failing. On that mission, Starship failed at roughly the same point of its ascent, just before the cutoff of the vehicle’s six methane-fueled Raptor engines.

Back then, a handful of photos and images from the Florida Keys and Puerto Rico showed debris in the sky after Starship activated its self-destruct mechanism due to an onboard fire caused by a dump of liquid oxygen propellant. But that flight occurred in the morning, with bright sunlight along the ship’s flight path.

This time, the ship disintegrated and reentered the atmosphere at dusk, with impeccable lighting conditions accentuating the debris cloud’s appearance. These twilight conditions likely contributed to the plethora of videos posted to social media on Thursday.

Starship and Super Heavy head downrange from SpaceX’s launch site near Brownsville, Texas. Credit: SpaceX

The third Starship test flight last March saw the spacecraft reach its planned trajectory and fly halfway around the world before succumbing to the scorching heat of atmospheric reentry. In June, the fourth test flight ended with controlled splashdowns of the rocket’s Super Heavy booster in the Gulf of Mexico and of Starship in the Indian Ocean.

In October, SpaceX caught the Super Heavy booster with mechanical arms at the launch pad for the first time, proving out the company’s audacious approach to recovering and reusing the rocket. On this fifth test flight, SpaceX modified the ship’s heat shield to better handle the hot temperatures of reentry, and the vehicle again made it to an on-target splashdown in the Indian Ocean.

Most recently, Flight 6 on November 19 demonstrated the ship’s ability to reignite its Raptor engines in space for the first time and again concluded with a bullseye splashdown. But SpaceX aborted an attempt to again catch the booster back at Starbase due to a problem with sensors on the launch pad’s tower.

With Flight 7, SpaceX hoped to test more changes to the heat shield protecting Starship from reentry temperatures up to 2,600° Fahrenheit (1,430° Celsius). Musk has identified the heat shield as one of the most difficult challenges still facing the program. In order for SpaceX to reach its ambition for the ship to become rapidly reusable, with minimal or no refurbishment between flights, the heat shield must be resilient and durable.

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A solid electrolyte gives lithium-sulfur batteries ludicrous endurance

batteries, chemistry, electrolyte, lithium battery, lithium-sulfur battery, Science, solid electrolyte / Kris Guyer / January 17, 2025

Sulfur can store a lot more lithium but is problematically reactive in batteries.

If you weren’t aware, sulfur is pretty abundant. Credit: P_Wei

Lithium may be the key component in most modern batteries, but it doesn’t make up the bulk of the material used in them. Instead, much of the material is in the electrodes, where the lithium gets stored when the battery isn’t charging or discharging. So one way to make lighter and more compact lithium-ion batteries is to find electrode materials that can store more lithium. That’s one of the reasons that recent generations of batteries are starting to incorporate silicon into the electrode materials.

There are materials that can store even more lithium than silicon; a notable example is sulfur. But sulfur has a tendency to react with itself, producing ions that can float off into the electrolyte. Plus, like any electrode material, it tends to expand in proportion to the amount of lithium that gets stored, which can create physical strains on the battery’s structure. So while it has been easy to make lithium-sulfur batteries, their performance has tended to degrade rapidly.

But this week, researchers described a lithium-sulfur battery that still has over 80 percent of its original capacity after 25,000 charge/discharge cycles. All it took was a solid electrolyte that was more reactive than the sulfur itself.

When lithium meets sulfur…

Sulfur is an attractive battery material. It’s abundant and cheap, and sulfur atoms are relatively lightweight compared to many of the other materials used in battery electrodes. Sodium-sulfur batteries, which rely on two very cheap raw materials, have already been developed, although they only work at temperatures high enough to melt both of these components. Lithium-sulfur batteries, by contrast, could operate more or less the same way that current lithium-ion batteries do.

With a few major exceptions, that is. One is that the elemental sulfur used as an electrode is a very poor conductor of electricity, so it has to be dispersed within a mesh of conductive material. (You can contrast that with graphite, which both stores lithium and conducts electricity relatively well, thanks to being composed of countless sheets of graphene.) Lithium is stored there as Li₂S, which occupies substantially more space than the elemental sulfur it’s replacing.

Both of these issues, however, can be solved with careful engineering of the battery’s structure. A more severe problem comes from the properties of the lithium-sulfur reactions that occur at the electrode. Elemental sulfur exists as an eight-atom ring, and the reactions with lithium are slow enough that semi-stable intermediates with smaller chains of sulfur end up forming. Unfortunately, these tend to be soluble in most electrolytes, allowing them to travel to the opposite electrode and participate in chemical reactions there.

This process essentially discharges the battery without allowing the electrons to be put to use. And it gradually leaves the electrode’s sulfur unavailable for participating in future charge/discharge cycles. The net result is that early generations of the technology would discharge themselves while sitting unused and would only survive a few hundred cycles before performance decayed dramatically.

But there has been progress on all these fronts, and some lithium-sulfur batteries with performance similar to lithium-ion have been demonstrated. Late last year, a company announced that it had lined up the money needed to build the first large-scale lithium-sulfur battery factory. Still, work on improvements has continued, and the new work seems to suggest ways to boost performance well beyond lithium-ion.

The need for speed

The paper describing the new developments, done by a collaboration between Chinese and German researchers, focuses on one aspect of the challenges posed by lithium-sulfur batteries: the relatively slow chemical reaction between lithium ions and elemental sulfur. It presents that aspect as a roadblock to fast charging, something that will be an issue for automotive applications. But at the same time, finding a way to limit the formation of inactive intermediate products during this reaction goes to the root of the relatively short usable life span of lithium-sulfur batteries.

As it turns out, the researchers found two.

One of the problems with the lithium-sulfur reaction intermediates is that they dissolve in most electrolytes. But that’s not a problem if the electrolyte isn’t a liquid. Solid electrolytes are materials that have a porous structure at the atomic level, with the environment inside the pores being favorable for ions. This allows ions to diffuse through the solid. If there’s a way to trap ions on one side of the electrolyte, such as a chemical reaction that traps or de-ionizes them, then it can enable one-way travel.

Critically, pores that favor the transit of lithium ions, which are quite compact, aren’t likely to allow the transit of the large ionized chains of sulfur. So a solid electrolyte should help cut down on the problems faced by lithium-sulfur batteries. But it won’t necessarily help with fast charging.

The researchers began by testing a glass formed from a mixture of boron, sulfur, and lithium (B₂S₃ and Li₂S). But this glass had terrible conductivity, so they started experimenting with related glasses and settled on a combination that substituted in some phosphorus and iodine.

The iodine turned out to be a critical component. While the exchange of electrons with sulfur is relatively slow, iodine undergoes electron exchange (technically termed a redox reaction) extremely quickly. So it can act as an intermediate in the transfer of electrons to sulfur, speeding up the reactions that occur at the electrode. In addition, iodine has relatively low melting and boiling points, and the researchers suggest there’s some evidence that it moves around within the electrolyte, allowing it to act as an electron shuttle.

Successes and caveats

The result is a far superior electrolyte—and one that enables fast charging. It’s typical that fast charging cuts into the total capacity that can be stored in a battery. But when charged at an extraordinarily fast rate (50C, meaning a full charge in just over a minute), a battery based on this system still had half the capacity of a battery charged 25 times more slowly (2C, or a half-hour to full charge).

But the striking thing was how durable the resulting battery was. Even at an intermediate charging rate (5C), it still had over 80 percent of its initial capacity after over 25,000 charge/discharge cycles. By contrast, lithium-ion batteries tend to hit that level of decay after about 1,000 cycles. If that sort of performance is possible in a mass-produced battery, it’s only a slight exaggeration to say it can radically alter our relationships with many battery-powered devices.

What’s not at all clear, however, is whether this takes full advantage of one of the original promises of lithium-sulfur batteries: more charge in a given weight and volume. The researchers specify the battery being used for testing; one electrode is an indium/lithium metal foil, and the other is a mix of carbon, sulfur, and the glass electrolyte. A layer of the electrolyte sits between them. But when giving numbers for the storage capacity per weight, only the weight of the sulfur is mentioned.

Still, even if weight issues would preclude this from being stuffed into a car or cell phone, there are plenty of storage applications that would benefit from something that doesn’t wear out even with 65 years of daily cycling.

Nature, 2025. DOI: 10.1038/s41586-024-08298-9 (About DOIs).

John is Ars Technica’s science editor. He has a Bachelor of Arts in Biochemistry from Columbia University, and a Ph.D. in Molecular and Cell Biology from the University of California, Berkeley. When physically separated from his keyboard, he tends to seek out a bicycle, or a scenic location for communing with his hiking boots.

A solid electrolyte gives lithium-sulfur batteries ludicrous endurance Read More »

Here’s what NASA would like to see SpaceX accomplish with Starship this year

artemis, Commercial space, human spaceflight, launch, moon, NASA, Science, Space, spacex, Starbase, starship, texas / Kris Guyer / January 16, 2025

Iterate, iterate, and iterate some more

The seventh test flight of Starship is scheduled for launch Thursday afternoon.

SpaceX’s upgraded Starship rocket stands on its launch pad at Starbase, Texas. Credit: SpaceX

SpaceX plans to launch the seventh full-scale test flight of its massive Super Heavy booster and Starship rocket Thursday afternoon. It’s the first of what might be a dozen or more demonstration flights this year as SpaceX tries new things with the most powerful rocket ever built.

There are many things on SpaceX’s Starship to-do list in 2025. They include debuting an upgraded, larger Starship, known as Version 2 or Block 2, on the test flight preparing to launch Thursday. The one-hour launch window opens at 5 pm EST (4 pm CST; 22: 00 UTC) at SpaceX’s launch base in South Texas. You can watch SpaceX’s live webcast of the flight here.

SpaceX will again attempt to catch the rocket’s Super Heavy booster—more than 20 stories tall and wider than a jumbo jet—back at the launch pad using mechanical arms, or “chopsticks,” mounted to the launch tower. Read more about the Starship Block 2 upgrades in our story from last week.

You might think of next week’s Starship test flight as an apéritif before the entrées to come. Ars recently spoke with Lisa Watson-Morgan, the NASA engineer overseeing the agency’s contract with SpaceX to develop a modified version of Starship to land astronauts on the Moon. NASA has contracts with SpaceX worth more than $4 billion to develop and fly two Starship human landing missions under the umbrella of the agency’s Artemis program to return humans to the Moon.

We are publishing the entire interview with Watson-Morgan below, but first, let’s assess what SpaceX might accomplish with Starship this year.

There are many things to watch for on this test flight, including the deployment of 10 satellite simulators to test the ship’s payload accommodations and the performance of a beefed-up heat shield as the vehicle blazes through the atmosphere for reentry and splashdown in the Indian Ocean.

If this all works, SpaceX may try to launch a ship into low-Earth orbit on the eighth flight, expected to launch in the next couple of months. All of the Starship test flights to date have intentionally flown on suborbital trajectories, bringing the ship back toward reentry over the sea northwest of Australia after traveling halfway around the world.

Then, there’s an even bigger version of Starship called Block 3 that could begin flying before the end of the year. This version of the ship is the one that SpaceX will use to start experimenting with in-orbit refueling, according to Watson-Morgan.

In order to test refueling, two Starships will dock together in orbit, allowing one vehicle to transfer super-cold methane and liquid oxygen into the other. Nothing like this on this scale has ever been attempted before. Future Starship missions to the Moon and Mars may require 10 or more tanker missions to gas up in low-Earth orbit. All of these missions will use different versions of the same basic Starship design: a human-rated lunar lander, a propellant depot, and a refueling tanker.

Artist’s illustration of Starship on the surface of the Moon. Credit: SpaceX

Questions for 2025

Catching Starship back at its launch tower and demonstrating orbital propellant transfer are the two most significant milestones on SpaceX’s roadmap for 2025.

SpaceX officials have said they aim to fly as many as 25 Starship missions this year, allowing engineers to more rapidly iterate on the vehicle’s design. SpaceX is constructing a second launch pad at its Starbase facility near Brownsville, Texas, to help speed up the launch cadence.

Can SpaceX achieve this flight rate in 2025? Will faster Starship manufacturing and reusability help the company fly more often? Will SpaceX fly its first ship-to-ship propellant transfer demonstration this year? When will Starship begin launching large batches of new-generation Starlink Internet satellites?

Licensing delays at the Federal Aviation Administration have been a thorn in SpaceX’s side for the last couple of years. Will those go away under the incoming administration of President-elect Donald Trump, who counts SpaceX founder Elon Musk as a key adviser?

And will SpaceX gain a larger role in NASA’s Artemis lunar program? The Artemis program’s architecture is sure to be reviewed by the Trump administration and the nominee for the agency’s next administrator, billionaire businessman and astronaut Jared Isaacman.

The very expensive Space Launch System rocket, developed by NASA with Boeing and other traditional aerospace contractors, might be canceled. NASA currently envisions the SLS rocket and Orion spacecraft as the transportation system to ferry astronauts between Earth and the vicinity of the Moon, where crews would meet up with a landing vehicle provided by commercial partners SpaceX and Blue Origin.

Watson-Morgan didn’t have answers to all of these questions. Many of them are well outside of her purview as Human Landing System program manager, so Ars didn’t ask. Instead, Ars discussed technical and schedule concerns with her during the half-hour interview. Here is one part of the discussion, lightly edited for clarity.

Ars: What do you hope to see from Flight 7 of Starship?

Lisa Watson-Morgan: One of the exciting parts of working with SpaceX are these test flights. They have a really fast turnaround, where they put in different lessons learned. I think you saw many of the flight objectives that they discussed from Flight 6, which was a great success. I think they mentioned different thermal testing experiments that they put on the ship in order to understand the different heating, the different loads on certain areas of the system. All that was really good with each one of those, in addition to how they configure the tiles. Then, from that, there’ll be additional tests that they will put on Flight 7, so you kind of get this iterative improvement and learning that we’ll get to see in Flight 7. So Flight 7 is the first Version 2 of their ship set. When I say that, I mean the ship, the booster, all the systems associated with it. So, from that, it’s really more just understanding how the system, how the flaps, how all of that interacts and works as they’re coming back in. Hopefully we’ll get to see some catches, that’s always exciting.

Ars: How did the in-space Raptor engine relight go on Flight 6 (on November 19)?

Lisa Watson-Morgan: Beautifully. And that’s something that’s really important to us because when we’re sitting on the Moon… well, actually, the whole path to the Moon as we are getting ready to land on the Moon, we’ll perform a series of maneuvers, and the Raptors will have an environment that is very, very cold. To that, it’s going to be important that they’re able to relight for landing purposes. So that was a great first step towards that. In addition, after we land, clearly the Raptors will be off, and it will get very cold, and they will have to relight in a cold environment (to get off the Moon). So that’s why that step was critical for the Human Landing System and NASA’s return to the Moon.

A recent artist’s illustration of two Starships docked together in low-Earth orbit. Credit: SpaceX

Ars: Which version of the ship is required for the propellant transfer demonstration, and what new features are on that version to enable this test?

Lisa Watson-Morgan: We’re looking forward to the Version 3, which is what’s coming up later on, sometime in ’25, in the near term, because that’s what we need for propellant transfer and the cryo fluid work that is also important to us… There are different systems in the V3 set that will help us with cryo fluid management. Obviously, with those, we have to have the couplers and the quick-disconnects in order for the two systems to have the right guidance, navigation, trajectory, all the control systems needed to hold their station-keeping in order to dock with each other, and then perform the fluid transfer. So all the fluid lines and all that’s associated with that, those systems, which we have seen in tests and held pieces of when we’ve been working with them at their site, we’ll get to see those actually in action on orbit.

Ars: Have there been any ground tests of these systems, whether it’s fluid couplers or docking systems? Can you talk about some of the ground tests that have gone into this development?

Lisa Watson-Morgan: Oh, absolutely. We’ve been working with them on ground tests for this past year. We’ve seen the ground testing and reviewed the data. Our team works with them on what we deem necessary for the various milestones. While the milestone contains proprietary (information), we work closely with them to ensure that it’s going to meet the intent, safety-wise as well as technically, of what we’re going to need to see. So they’ve done that.

Even more exciting, they have recently shipped some of their docking systems to the Johnson Space Center for testing with the Orion Lockheed Martin docking system, and that’s for Artemis III. Clearly, that’s how we’re going to receive the crew. So those are some exciting tests that we’ve been doing this past year as well that’s not just focused on, say, the booster and the ship. There are a lot of crew systems that are being developed now. We’re in work with them on how we’re going to effectuate the crew manual control requirements that we have, so it’s been a great balance to see what the crew needs, given the size of the ship. That’s been a great set of work. We have crew office hours where the crew travels to Hawthorne [SpaceX headquarters in California] and works one-on-one with the different responsible engineers in the different technical disciplines to make sure that they understand not just little words on the paper from a requirement, but actually what this means, and then how systems can be operated.

Ars: For the docking system, Orion uses the NASA Docking System, and SpaceX brings its own design to bear on Starship?

Lisa Watson-Morgan: This is something that I think the Human Landing System has done exceptionally well. When we wrote our high-level set of requirements, we also wrote it with a bigger picture in mind—looked into the overall standards of how things are typically done, and we just said it has to be compliant with it. So it’s a docking standard compliance, and SpaceX clearly meets that. They certainly do have the Dragon heritage, of course, with the International Space Station. So, because of that, we have high confidence that they’re all going to work very well. Still, it’s important to go ahead and perform the ground testing and get as much of that out of the way as we can.

Lisa Watson-Morgan, NASA’s HLS program manager, is based at Marshall Space Flight Center in Huntsville, Alabama. Credit: ASA/Aubrey Gemignani

Ars: How far along is the development and design of the layout of the crew compartment at the top of Starship? Is it far along, or is it still in the conceptual phase? What can you say about that?

Lisa Watson-Morgan: It’s much further along there. We’ve had our environmental control and life support systems, whether it’s carbon dioxide monitoring fans to make sure the air is circulating properly. We’ve been in a lot of work with SpaceX on the temperature. It’s… a large area (for the crew). The seats, making sure that the crew seats and the loads on that are appropriate. For all of that work, as the analysis work has been performed, the NASA team is reviewing it. They had a mock-up, actually, of some of their life support systems even as far back as eight-plus months ago. So there’s been a lot of progress on that.

Ars: Is SpaceX planning to use a touchscreen design for crew displays and controls, like they do with the Dragon spacecraft?

Lisa Watson-Morgan: We’re in talks about that, about what would be the best approach for the crew for the dynamic environment of landing.

Ars: I can imagine it is a pretty dynamic environment with those Raptor engines firing. It’s almost like a launch in reverse.

Lisa Watson-Morgan: Right. Those are some of the topics that get discussed in the crew office hours. That’s why it’s good to have the crew interacting directly, in addition to the different discipline leads, whether it’s structural, mechanical, propulsion, to have all those folks talking guidance and having control to say, “OK, well, when the system does this, here’s the mode we expect to see. Here’s the impact on the crew. And is this condition, or is the option space that we have on the table, appropriate for the next step, with respect to the displays.”

Ars: One of the big things SpaceX needs to prove out before going to the Moon with Starship is in-orbit propellant transfer. When do you see the ship-to-ship demonstration occurring?

Lisa Watson-Morgan: I see it occurring in ’25.

Ars: Anything more specific about the schedule for that?

Lisa Watson-Morgan: That’d be a question for SpaceX because they do have a number of flights that they’re performing commercially, for their maturity. We get the benefit of that. It’s actually a great partnership. I’ll tell you, it’s really good working with them on this, but they’d have to answer that question. I do foresee it happening in ’25.

Ars: What things do you need to see SpaceX accomplish before they’re ready for the refueling demo? I’m thinking of things like the second launch tower, potentially. Do they need to demonstrate a ship catch or anything like that before going for orbital refueling?

Lisa Watson-Morgan: I would say none of that’s required. You just kind of get down to, what are the basics? What are the basics that you need? So you need to be able to launch rapidly off the same pad, even. They’ve shown they can launch and catch within a matter of minutes. So that is good confidence there. The catching is part of their reuse strategy, which is more of their commercial approach, and not a NASA requirement. NASA reaps the benefit of it by good pricing as a result of their commercial model, but it is not a requirement that we have. So they could theoretically use the same pad to perform the propellant transfer and the long-duration flight, because all it requires is two launches, really, within a specified time period to where the two systems can meet in a planned trajectory or orbit to do the propellant transfer. So they could launch the first one, and then within a week or two or three, depending on what the concept of operations was that we thought we could achieve at that time, and then have the propellant transfer demo occur that way. So you don’t necessarily need two pads, but you do need more thermal characterization of the ship. I would say that is one of the areas (we need to see data on), and that is one of the reasons, I think, why they’re working so diligently on that.

Ars: You mentioned the long-duration flight demonstration. What does that entail?

Lisa Watson-Morgan: The simple objectives are to launch two different tankers or Starships. The Starship will eventually be a crewed system. Clearly, the ones that we’re talking about for the propellant transfer are not. It’s just to have the booster and Starship system launch, and within a few weeks, have another one launch, and have them rendezvous. They need to be able to find each other with their sensors. They need to be able to come close, very, very close, and they need to be able to dock together, connect, do the quick connect, and make sure they are able, then, to flow propellant and LOX (liquid oxygen) to another system. Then, we need to be able to measure the quantity of how much has gone over. And from that, then they need to safely undock and dispose.

Ars: So the long-duration flight demonstration is just part of what SpaceX needs to do in order to be ready for the propellant transfer demonstration?

Lisa Watson-Morgan: We call it long duration just because it’s not a 45-minute or an hour flight. Long duration, obviously, that’s a relative statement, but it’s a system that can stay up long enough to be able to find another Starship and perform those maneuvers and flow of fuel and LOX.

Ars: How much propellant will you transfer with this demonstration, and do you think you’ll get all the data you need in one demonstration, or will SpaceX need to try this several times?

Lisa Watson-Morgan: That’s something you can ask SpaceX (about how much propellant will be transferred). Clearly, I know, but there’s some sensitivity there. You’ve seen our requirements in our initial solicitation. We have thresholds and goals, meaning we want you to at least do this, but more is better, and that’s typically how we work almost everything. Working with commercial industry in these fixed-price contracts has worked exceptionally well, because when you have providers that are also wanting to explore commercially or trying to make a commercial system, they are interested in pushing more than what we would typically ask for, and so often we get that for an incredibly fair price.

Stephen Clark is a space reporter at Ars Technica, covering private space companies and the world’s space agencies. Stephen writes about the nexus of technology, science, policy, and business on and off the planet.

Here’s what NASA would like to see SpaceX accomplish with Starship this year Read More »