Science – Page 12

Complexity physics finds crucial tipping points in chess games

chess, mathematics, networks, phase transitions, Physics, Science, tipping points / Shannon Garcia / January 24, 2025

For his analysis, Barthelemy chose to represent chess as a decision tree in which each “branch” leads to a win, loss, or draw. Players face the challenge of finding the best move amid all this complexity, particularly midgame, in order to steer gameplay into favorable branches. That’s where those crucial tipping points come into play. Such positions are inherently unstable, which is why even a small mistake can have a dramatic influence on a match’s trajectory.

A case of combinatorial complexity

Barthelemy has re-imagined a chess match as a network of forces in which pieces act as the network’s nodes, and the ways they interact represent the edges, using an interaction graph to capture how different pieces attack and defend one another. The most important chess pieces are those that interact with many other pieces in a given match, which he calculated by measuring how frequently a node lies on the shortest path between all the node pairs in the network (its “betweenness centrality”).

He also calculated so-called “fragility scores,” which indicate how easy it is to remove those critical chess pieces from the board. And he was able to apply this analysis to more than 20,000 actual chess matches played by the world’s top players over the last 200 years.

Barthelemy found that his metric could indeed identify tipping points in specific matches. Furthermore, when he averaged his analysis over a large number of games, an unexpected universal pattern emerged. “We observe a surprising universality: the average fragility score is the same for all players and for all openings,” Barthelemy writes. And in famous chess matches, “the maximum fragility often coincides with pivotal moments, characterized by brilliant moves that decisively shift the balance of the game.”

Specifically, fragility scores start to increase about eight moves before the critical tipping point position occurs and stay high for some 15 moves after that. “These results suggest that positional fragility follows a common trajectory, with tension peaking in the middle game and dissipating toward the endgame,” he writes. “This analysis highlights the complex dynamics of chess, where the interaction between attack and defense shapes the game’s overall structure.”

Physical Review E, 2025. DOI: 10.1103/PhysRevE.00.004300 (About DOIs).

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Researchers optimize simulations of molecules on quantum computers

catalysts, Computer science, electrons, Physics, quantum computing, quantum mechanics, Science / Kelly Newman / January 24, 2025

The net result is a much faster operation involving far fewer gates. That’s important because errors in quantum hardware increase as a function of both time and the number of operations.

The researchers then used this approach to explore a chemical, Mn₄O₅Ca, that plays a key role in photosynthesis. Using this approach, they showed it’s possible to calculate what’s called the “spin ladder,” or the list of the lowest-energy states the electrons can occupy. The energy differences between these states correspond to the wavelengths of light they can absorb or emit, so this also defines the spectrum of the molecule.

Faster, but not quite fast enough

We’re not quite ready to run this system on today’s quantum computers, as the error rates are still a bit too high. But because the operations needed to run this sort of algorithm can be done so efficiently, the error rates don’t have to come down very much before the system will become viable. The primary determinant of whether it will run into an error is how far down the time dimension you run the simulation, plus the number of measurements of the system you take over that time.

“The algorithm is especially promising for near-term devices having favorable resource requirements quantified by the number of snapshots (sample complexity) and maximum evolution time (coherence) required for accurate spectral computation,” the researchers wrote.

But the work also makes a couple of larger points. The first is that quantum computers are fundamentally unlike other forms of computation we’ve developed. They’re capable of running things that look like traditional algorithms, where operations are performed and a result is determined. But they’re also quantum systems that are growing in complexity with each new generation of hardware, which makes them great at simulating other quantum systems. And there are a number of hard problems involving quantum systems we’d like to solve.

In some ways, we may only be starting to scratch the surface of quantum computers’ potential. Up until quite recently, there were a lot of hypotheticals; it now appears we’re on the cusp of using one for some potentially useful computations. And that means more people will start thinking about clever ways we can solve problems with them—including cases like this, where the hardware would be used in ways its designers might not have even considered.

Nature Physics, 2025. DOI: 10.1038/s41567-024-02738-z (About DOIs).

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

Science / Shannon Garcia / 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 / DJ Henderson / 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 / Shannon Garcia / 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 / 9u50fv / 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 / Kelly Newman / 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 / Beth Washington / 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 / DJ Henderson / 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 / Shannon Garcia / 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 / DJ Henderson / 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 / DJ Henderson / 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.

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