Science

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Researchers use AI to design proteins that block snake venom toxins

AI, anti-toxin, biochemistry, Computer science, protein design, Science, snakes, venom / /

Since these two toxicities work through entirely different mechanisms, the researchers tackled them separately.

Blocking a neurotoxin

The neurotoxic three-fingered proteins are a subgroup of the larger protein family that specializes in binding to and blocking the receptors for acetylcholine, a major neurotransmitter. Their three-dimensional structure, which is key to their ability to bind these receptors, is based on three strings of amino acids within the protein that nestle against each other (for those that have taken a sufficiently advanced biology class, these are anti-parallel beta sheets). So to interfere with these toxins, the researchers targeted these strings.

They relied on an AI package called RFdiffusion (the RF denotes its relation to the Rosetta Fold protein-folding software). RFdiffusion can be directed to design protein structures that are complements to specific chemicals; in this case, it identified new strands that could line up along the edge of the ones in the three-fingered toxins. Once those were identified, a separate AI package, called ProteinMPNN, was used to identify the amino acid sequence of a full-length protein that would form the newly identified strands.

But we’re not done with the AI tools yet. The combination of three-fingered toxins and a set of the newly designed proteins were then fed into DeepMind’s AlfaFold2 and the Rosetta protein structure software, and the strength of the interactions between them were estimated.

It’s only at this point that the researchers started making actual proteins, focusing on the candidates that the software suggested would interact the best with the three-fingered toxins. Forty-four of the computer-designed proteins were tested for their ability to interact with the three-fingered toxin, and the single protein that had the strongest interaction was used for further studies.

At this point, it was back to the AI, where RFDiffusion was used to suggest variants of this protein that might bind more effectively. About 15 percent of its suggestions did, in fact, interact more strongly with the toxin. The researchers then made both the toxin and the strongest inhibitor in bacteria and obtained the structure of their interactions. This confirmed that the software’s predictions were highly accurate.

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Meta takes us a step closer to Star Trek’s universal translator

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The computer science behind translating speech from 100 source languages.

In 2023, AI researchers at Meta interviewed 34 native Spanish and Mandarin speakers who lived in the US but didn’t speak English. The goal was to find out what people who constantly rely on translation in their day-to-day activities expect from an AI translation tool. What those participants wanted was basically a Star Trek universal translator or the Babel Fish from the Hitchhiker’s Guide to the Galaxy: an AI that could not only translate speech to speech in real time across multiple languages, but also preserve their voice, tone, mannerisms, and emotions. So, Meta assembled a team of over 50 people and got busy building it.

What this team came up with was a next-gen translation system called Seamless. The first building block of this system is described in Wednesday’s issue of Nature; it can translate speech among 36 different languages.

Language data problems

AI translation systems today are mostly focused on text, because huge amounts of text are available in a wide range of languages thanks to digitization and the Internet. Institutions like the United Nations or European Parliament routinely translate all their proceedings into the languages of all their member states, which means there are enormous databases comprising aligned documents prepared by professional human translators. You just needed to feed those huge, aligned text corpora into neural nets (or hidden Markov models before neural nets became all the rage) and you ended up with a reasonably good machine translation system. But there were two problems with that.

The first issue was those databases comprised formal documents, which made the AI translators default to the same boring legalese in the target language even if you tried to translate comedy. The second problem was speech—none of this included audio data.

The problem of language formality was mostly solved by including less formal sources like books, Wikipedia, and similar material in AI training databases. The scarcity of aligned audio data, however, remained. Both issues were at least theoretically manageable in high-resource languages like English or Spanish, but they got dramatically worse in low-resource languages like Icelandic or Zulu.

As a result, the AI translators we have today support an impressive number of languages in text, but things are complicated when it comes to translating speech. There are cascading systems that simply do this trick in stages. An utterance is first converted to text just as it would be in any dictation service. Then comes text-to-text translation, and finally the resulting text in the target language is synthesized into speech. Because errors accumulate at each of those stages, the performance you get this way is usually poor, and it doesn’t work in real time.

A few systems that can translate speech-to-speech directly do exist, but in most cases they only translate into English and not in the opposite way. Your foreign language interlocutor can say something to you in one of the languages supported by tools like Google’s AudioPaLM, and they will translate that to English speech, but you can’t have a conversation going both ways.

So, to pull off the Star Trek universal translator thing Meta’s interviewees dreamt about, the Seamless team started with sorting out the data scarcity problem. And they did it in a quite creative way.

Building a universal language

Warren Weaver, a mathematician and pioneer of machine translation, argued in 1949 that there might be a yet undiscovered universal language working as a common base of human communication. This common base of all our communication was exactly what the Seamless team went for in its search for data more than 70 years later. Weaver’s universal language turned out to be math—more precisely, multidimensional vectors.

Machines do not understand words as humans do. To make sense of them, they need to first turn them into sequences of numbers that represent their meaning. Those sequences of numbers are numerical vectors that are termed word embeddings. When you vectorize tens of millions of documents this way, you’ll end up with a huge multidimensional space where words with similar meaning that often go together, like “tea” and “coffee,” are placed close to each other. When you vectorize aligned text in two languages like those European Parliament proceedings, you end up with two separate vector spaces, and then you can run a neural net to learn how those two spaces map onto each other.

But the Meta team didn’t have those nicely aligned texts for all the languages they wanted to cover. So, they vectorized all texts in all languages as if they were just a single language and dumped them into one embedding space called SONAR (Sentence-level Multimodal and Language-Agnostic Representations). Once the text part was done, they went to speech data, which was vectorized using a popular W2v (word to vector) tool and added it to the same massive multilingual, multimodal space. Of course, each embedding carried metadata identifying its source language and whether it was text or speech before vectorization.

The team just used huge amounts of raw data—no fancy human labeling, no human-aligned translations. And then, the data mining magic happened.

SONAR embeddings represented entire sentences instead of single words. Part of the reason behind that was to control for differences between morphologically rich languages, where a single word may correspond to multiple words in morphologically simple languages. But the most important thing was that it ensured that sentences with similar meaning in multiple languages ended up close to each other in the vector space.

It was the same story with speech, too—a spoken sentence in one language was close to spoken sentences in other languages with similar meaning. It even worked between text and speech. So, the team simply assumed that embeddings in two different languages or two different modalities (speech or text) that are at a sufficiently close distance to each other are equivalent to the manually aligned texts of translated documents.

This produced huge amounts of automatically aligned data. The Seamless team suddenly got access to millions of aligned texts, even in low-resource languages, along with thousands of hours of transcribed audio. And they used all this data to train their next-gen translator.

Seamless translation

The automatically generated data set was augmented with human-curated texts and speech samples where possible and used to train multiple AI translation models. The largest one was called SEAMLESSM4T v2. It could translate speech to speech from 101 source languages into any of 36 output languages, and translate text to text. It would also work as an automatic speech recognition system in 96 languages, translate speech to text from 101 into 96 languages, and translate text to speech from 96 into 36 languages—all from a single unified model. It also outperformed state-of-the-art cascading systems by 8 percent in a speech-to-text and by 23 percent in a speech-to-speech translations based on the scores in Bilingual Evaluation Understudy (an algorithm commonly used to evaluate the quality of machine translation).

But it can now do even more than that. The Nature paper published by Meta’s Seamless ends at the SEAMLESSM4T models, but Nature has a long editorial process to ensure scientific accuracy. The paper published on January 15, 2025, was submitted in late November 2023. But in a quick search of the arXiv.org, a repository of not-yet-peer-reviewed papers, you can find the details of two other models that the Seamless team has already integrated on top of the SEAMLESSM4T: SeamlessStreaming and SeamlessExpressive, which take this AI even closer to making a Star Trek universal translator a reality.

SeamlessStreaming is meant to solve the translation latency problem. The baseline SEAMLESSM4T, despite all the bells and whistles, worked as a standard AI translation tool. You had to say what you wanted to say, push “translate,” and it spat out the translation. SeamlessStreaming was designed to take this experience a bit closer to what human simultaneous translator do—it translates what you’re saying as you speak in a streaming fashion. SeamlessExpressive, on the other hand, is aimed at preserving the way you express yourself in translations. When you whisper or say something in a cheerful manner or shout out with anger, SeamlessExpressive will encode the features of your voice, like tone, prosody, volume, tempo, and so on, and transfer those into the output speech in the target language.

Sadly, it still can’t do both at the same time; you can only choose to go for either streaming or expressivity, at least at the moment. Also, the expressivity variant is very limited in supported languages—it only works in English, Spanish, French, and German. But at least it’s online so you can go ahead and give it a spin.

Nature, 2025.  DOI: 10.1038/s41586-024-08359-z

Photo of Jacek Krywko

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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Is humanity alone in the Universe? What scientists really think.

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News stories about the likely existence of extraterrestrial life, and our chances of detecting it, tend to be positive. We are often told that we might discover it any time now. Finding life beyond Earth is “only a matter of time,” we were told in September 2023. “We are close” was a headline from September 2024.

It’s easy to see why. Headlines such as “We’re probably not close” or “Nobody knows” aren’t very clickable. But what does the relevant community of experts actually think when considered as a whole? Are optimistic predictions common or rare? Is there even a consensus? In our new paper, published in Nature Astronomy, we’ve found out.

During February to June 2024, we carried out four surveys regarding the likely existence of basic, complex, and intelligent extraterrestrial life. We sent emails to astrobiologists (scientists who study extraterrestrial life), as well as to scientists in other areas, including biologists and physicists.

In total, 521 astrobiologists responded, and we received 534 non-astrobiologist responses. The results reveal that 86.6 percent of the surveyed astrobiologists responded either “agree” or “strongly agree” that it’s likely that extraterrestrial life (of at least a basic kind) exists somewhere in the universe.

Less than 2 percent disagreed, with 12 percent staying neutral. So, based on this, we might say that there’s a solid consensus that extraterrestrial life, of some form, exists somewhere out there.

Scientists who weren’t astrobiologists essentially concurred, with an overall agreement score of 88.4 percent. In other words, one cannot say that astrobiologists are biased toward believing in extraterrestrial life, compared with other scientists.

When we turn to “complex” extraterrestrial life or “intelligent” aliens, our results were 67.4 percent agreement, and 58.2 percent agreement, respectively for astrobiologists and other scientists. So, scientists tend to think that alien life exists, even in more advanced forms.

These results are made even more significant by the fact that disagreement for all categories was low. For example, only 10.2 percent of astrobiologists disagreed with the claim that intelligent aliens likely exist.

Is humanity alone in the Universe? What scientists really think. Read More »

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There was a straight shot from Earth to the Moon and Mars last night

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The most recent lunar occultation of Mars that was visible from the United States occurred on December 7, 2022. A handful of these events occur every few years around each Martian opposition, but they are usually only visible from a small portion of Earth, often over the ocean or in polar regions. The next lunar occultation of Mars visible across most of the United States will happen on the night of February 4–5, 2042. There are similar occultations of Mars in 2035, 2038, and 2039 visible in narrow swaths of South Florida and the Pacific Northwest.

This photo was taken with a handheld Canon 80D and a 600 mm lens. Settings were 1/2000 sec, f/8, ISO 400. The image was cropped and lightly edited in Adobe Lightroom.

The Moon also periodically covers Venus, Jupiter, Saturn, and the Solar System’s more distant planets. A good resource on lunar occultations is In-The-Sky.org, which lists events where the Moon will block out a planet or a bright star. Be sure you choose your location on the upper right corner of the page and toggle year by year to plan out future viewing opportunities.

Viewing these kinds of events can be breathtaking and humbling. In 2012, I was lucky enough to observe the transit of Venus in front of the Sun, something that only happens twice every 121 years.

Seeing Mars, twice the size of the Moon, rising above the lunar horizon like a rusty BB pellet next to a dusty volleyball provided a perfect illustration of the scale and grandeur of the Solar System. Similarly, viewing Venus dwarfed by the Sun was a revealing moment. The worlds accompanying Earth around the Sun are varied in size, shape, color, and composition.

In one glance, an observer can see the barren, airless lunar surface and a cold, desert planet that once harbored rivers, lakes, and potentially life, all while standing on our own planet, an oasis in the cosmos. One thing that connects them all is humanity’s quest for exploration. Today, robots are operating on or around the Moon and Mars. Governments and private companies are preparing to return astronauts to the lunar surface within a few years, then moving on to dispatch human expeditions to the red planet.

Plans to land astronauts on the Moon are already in motion, but significant financial and technological hurdles remain for a crew mission to put humans on Mars. But for a short time Monday night, it looked like there was a direct path.

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Maker of weight-loss drugs to ask Trump to pause price negotiations: Report

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Popular prescriptions

For now, Medicare does not cover drugs prescribed specifically for weight loss, but it will cover GLP-1 class drugs if they’re prescribed for other conditions, such as Type 2 diabetes. Wegovy, for example, is covered if it is prescribed to reduce the risk of heart attack and stroke in adults with either obesity or overweight. But, in November, the Biden administration proposed reinterpreting Medicare prescription-coverage rules to allow for coverage of “anti-obesity medications.”

Such a move is reportedly part of the argument Lilly’s CEO plans to bring to the Trump administration. Rather than using drug price negotiations to reduce health care costs, Ricks aims to play up the potential to reduce long-term health care costs by improving people’s overall health with coverage of GLP-1 drugs now. This argument would presumably be targeted at Mehmet Oz, the TV presenter and heart surgeon Trump has tapped to run the Centers for Medicare and Medicaid Services.

“My argument to Mehmet Oz is that if you want to protect Medicare costs in 10 years, have [the Affordable Care Act] and Medicare plans list these drugs now,” Ricks said to Bloomberg. “We know so much about how much cost savings there will be downstream in heart disease and other conditions.”

An October report from the Congressional Budget Office strongly disputed that claim, however. The CBO estimated that the direct cost of Medicare coverage for anti-obesity drugs between 2026 and 2034 would be nearly $39 billion, while the savings from improved health would total just a little over $3 billion, for a net cost to US taxpayers of about $35.5 billion.

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Up close and personal with the stag beetle in A Real Bug’s Life S2

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It’s just one of the many fascinating insect species featured in the second season of this NatGeo docuseries.

A female giant stag beetle Credit: National Geographic/Darlyne A. Murawski

A plucky male American stag beetle thinks he’s found a mate on a rotting old tree stump—and then realizes there’s another male eager to make the same conquest. The two beetles face off in battle, until the first manages to get enough leverage to toss his romantic rival off the stump in a deft display of insect jujitsu. It’s the first time this mating behavior has been captured on film, and the stag beetle is just one of the many fascinating insects featured in the second season of A Real Bug’s Life, a National Geographic docuseries narrated by Awkwafina.

The genesis for the docuseries lies in a past rumored sequel to Pixar’s 1998 animated film A Bug’s Life, which celebrated its 25th anniversary two years ago. That inspired producer Bill Markham, among others, to pitch a documentary series on a real bug’s life to National Geographic. “It was the quickest commission ever,” Markham told Ars last year. “It was such a good idea, to film bugs in an entertaining family way with Pixar sensibilities.” And thanks to the advent of new technologies—photogrammetry, probe and microscope lenses, racing drones, ultra-high-speed camera—plus a handful of skilled “bug wranglers,” the team was able to capture the bug’s-eye view of the world beautifully.

As with the Pixar film, the bugs (and adjacent creatures) are the main characters here, from cockroaches, monarch butterflies, and praying mantises to bees, spiders, and even hermit crabs. The 10 episodes, across two seasons, tell their stories as they struggle to survive in their respective habitats, capturing entire ecosystems in the process: city streets, a farm, the rainforest, a Texas backyard, and the African savannah, for example. Highlights from S1 included the first footage of cockroach egg casings hatching; wrangling army ants on location in a Costa Rica rainforest; and the harrowing adventures of a tiny jumping spider navigating the mean streets of New York City.

Looking for love

A luna moth perched on a twig. National Geographic/Nathan Small

S2 takes viewers to Malaysia’s tropical beaches, the wetlands of Derbyshire in England, and the forests of Tennessee’s Smoky Mountains. Among the footage highlights: Malaysian tiger beetles, who can run so fast they temporarily are unable to see; a young female hermit crab’s hunt for a bigger shell; and tiny peacock spiders hatching Down Under. There is also a special behind-the-scenes look for those viewers keen to learn more about how the episodes were filmed, involving 130 different species across six continents. Per the official synopsis:

A Real Bug’s Life is back for a thrilling second season that’s bolder than ever. Now, thanks to new cutting-edge filming technology, we are able to follow the incredible stories of the tiny heroes living in this hidden world, from the fast-legged tiger beetle escaping the heat of Borneo’s beaches to the magical metamorphosis of a damselfly on a British pond to the Smoky Mountain luna moth whose quest is to grow wings, find love and pass on his genes all in one short night. Join our witty guide, Awkwafina, on new bug journeys full of more mind-blowing behaviors and larger-than-life characters.

Entomologist Michael Carr, an environmental compliance officer for Santa Fe County in New Mexico, served as a field consultant for the “Love in the Forest” episode, which focuses on the hunt for mates by a luna moth, a firefly, and an American stag beetle. The latter species is Carr’s specialty, ever since he worked at the Smithsonian’s Museum of Natural History and realized the beetles flourished near where he grew up in Virginia. Since stag beetles are something of a niche species, NatGeo naturally tapped Carr as its field expert to help them find and film the insects in the Smoky Mountains. To do so, Carr set up a mercury vapor lamp on a tripod—”old style warehouse lights that take a little time to charge up,” which just happen to emit frequencies of light that attract different insect species.

Behind the scenes

Beetle expert Michael Carr and shooting researcher Katherine Hannaford film a stag beetle at night. National Geographic/Tom Oldridge

Stag beetles are saprocylic insects, according to Carr, so they seek out decaying wood and fungal communities. Males can fly as high as 30 feet to reach tree canopies, while the females can dig down to between 1 and 3 meters to lay their eggs in wood. Much of the stag beetle’s lifecycle is spent underground as a white grub molting into larger and larger forms before hatching in two to three years during the summer. Once their exoskeletons harden, they fly off to find mates and reproduce as quickly as possible. And if another male happens to get in their way, they’re quite prepared to do battle to win at love.

Stag beetles might be his specialty, but Carr found the fireflies also featured in that episode to be a particular highlight. “I grew up in rural Virginia,” Carr told Ars. “There was always fireflies, but I’d never seen anything like that until I was there on site. I did not realize, even though I’d grown up in the woods surrounded by fireflies, that, ‘Oh, the ones that are twinkling at the top, that’s one species. The ones in the middle that are doing a soft glow, that’s a different species.'”

And Carr was as surprised and fascinated as any newbie to learn about the “femme fatale” firefly: a species in which the female mimics the blinking patterns of other species of firefly, luring unsuspecting males to their deaths. The footage captured by the NatGeo crew includes a hair-raising segment where this femme fatale opts not to wait for her prey to come to her. A tasty male firefly has been caught in a spider’s web, and our daring, hungry lady flies right into the web to steal the prey:

A femme fatale firefly steals prey from a rival spider’s web.

Many people have a natural aversion to insects; Carr hopes that inventive docuseries like A Real Bug’s Life can help counter those negative perceptions by featuring some lesser-loved insects in anthropomorphized narratives—like the cockroaches and fire ants featured in S1. “[The series] did an amazing job of showing how something at that scale lives its life, and how that’s almost got a parallel to how we can live our life,” he said. “When you can get your mindset down to such a small scale and not just see them as moving dots on the ground and you see their eyes and you see how they move and how they behave and how they interact with each other, you get a little bit more appreciation for ants as a living organism.”

“By showcasing some of the bigger interesting insects like the femme fatale firefly or the big chivalrous stag beetle fighting over each other, or the dung beetle getting stomped by an elephant—those are some pretty amazing just examples of the biodiversity and breadth of insect life,” said Carr. “People don’t need to love insects. If they can, just, have some new modicum of respect, that’s good enough to change perspectives.”

The second season of A Real Bug’s Life premieres on January 15, 2025, on Disney+.

Photo of Jennifer Ouellette

Jennifer is a senior writer at Ars Technica with a particular focus on where science meets culture, covering everything from physics and related interdisciplinary topics to her favorite films and TV series. Jennifer lives in Baltimore with her spouse, physicist Sean M. Carroll, and their two cats, Ariel and Caliban.

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Skull long thought to be Cleopatra’s sister’s was actually a young boy

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Scientists have demonstrated that an ancient human skull excavated from a tomb at Ephesos was not that of Arsinoë IV, half-sister to Cleopatra VII. Rather, it’s the skull of a young male between the ages of 11 and 14 from Italy or Sardinia, who may have suffered from one or more developmental disorders, according to a new paper published in the journal Scientific Reports. Arsinoë IV’s remains are thus still missing.

Arsinoë IV led quite an adventurous short life. She was either the third or fourth daughter of Ptolemy XII, who left the throne to Cleopatra and his son, Ptolemy XIII, to rule together. Ptolemy XIII didn’t care for this decision and dethroned Cleopatra in a civil war—until Julius Caesar intervened to enforce their father’s original plan of co-rulership. As for Arsinoë, Caesar returned Cyprus to Egyptian rule and named her and her youngest brother (Ptolemy XIV) co-rulers. This time, it was Arsinoë who rebelled, taking command of the Egyptian army and declaring herself queen.

She was fairly successful at first in battling the Romans, conducting a siege against Alexandria and Cleopatra, until her disillusioned officers decided they’d had enough and secretly negotiated with Caesar to turn her over to him. Caesar agreed, and after a bit of public humiliation, he granted Arsinoë sanctuary in the temple of Artemis in Ephesus. She lived in relative peace for a few years, until Cleopatra and Mark Antony ordered her execution on the steps of the temple—a scandalous violation of the temple as a place of sanctuary. Historians disagree about Arsinoë’s age when she died: Estimates range from 22 to 27.

Archaeologists have been excavating the ancient city of Ephesus for more than a century. The Octagon was uncovered in 1904, and the burial chamber was opened in 1929. That’s where Joseph Keil found a skeleton in a sarcophagus filled with water, but for some reason, Keil only removed the cranium from the tomb before sealing it back up. He took the skull with him to Germany and declared it belonged to a likely female around 20 years old, although he provided no hard data to support that conclusion.

It was Hilke Thur of the Austrian Academy of Sciences who first speculated that the skull may have belonged to Arsinoë IV, despite the lack of an inscription (or even any grave goods) on the tomb where it was found. Old notes and photographs, as well as craniometry, served as the only evidence. The skull accompanied Keil to his new position at the University of Vienna, and there was one 1953 paper reporting on craniometric measurements, but after that, the skull languished in relative obscurity. Archaeologists at the University of Graz rediscovered the skull in Vienna in 2022. The rest of the skeleton remained buried until the chamber was reopened and explored further in the 1980s and 1990s, but it was no longer in the sarcophagus.

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Getting an all-optical AI to handle non-linear math

AI, Computer science, optical processing, optics, Science / /

The problem is that this cascading requires massive parallel computations that, when done on standard computers, take tons of energy and time. Bandyopadhyay’s team feels this problem can be solved by performing the equivalent operations using photons rather than electrons. In photonic chips, information can be encoded in optical properties like polarization, phase, magnitude, frequency, and wavevector. While this would be extremely fast and energy-efficient, building such chips isn’t easy.

Siphoning light

“Conveniently, photonics turned out to be particularly good at linear matrix operations,” Bandyopadhyay claims. A group at MIT led by Dirk Englund, a professor who is a co-author of Bandyopadhyay’s study, demonstrated a photonic chip doing matrix multiplication entirely with light in 2017. What the field struggled with, though, was implementing non-linear functions in photonics.

The usual solution, so far, relied on bypassing the problem by doing linear algebra on photonic chips and offloading non-linear operations to external electronics. This, however, increased latency, since the information had to be converted from light to electrical signals, processed on an external processor, and converted back to light. “And bringing the latency down is the primary reason why we want to build neural networks in photonics,” Bandyopadhyay says.

To solve this problem, Bandyopadhyay and his colleagues designed and built what is likely to be the world’s first chip that can compute the entire deep neural net, including both linear and non-linear operations, using photons. “The process starts with an external laser with a modulator that feeds light into the chip through an optical fiber. This way we convert electrical inputs to light,” Bandyopadhyay explains.

The light is then fanned out to six channels and fed into a layer of six neurons that perform linear matrix multiplication using an array of devices called Mach-Zehnder interferometers. “They are essentially programmable beam splitters, taking two optical fields and mixing them coherently to produce two output optical fields. By applying the voltage, you can control how much those the two inputs mix,” Bandyopadhyay says.

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Did Hilma af Klint draw inspiration from 19th century physics?

Hilma af Klint, Physics, Science, science and art, science illustrations, Thomas Young / /

Diagrams from Thomas Young’s 1807 Lectures bear striking resemblance to abstract figures in af Klint’s work.

Hilma af Klint’s Group IX/SUW, The Swan, No. 17, 1915. Credit: Hilma af Klimt Foundation

In 2019, astronomer Britt Lundgren of the University of North Carolina Asheville visited the Guggenheim Museum in New York City to take in an exhibit of the works of Swedish painter Hilma af Klint. Lundgren noted a striking similarity between the abstract geometric shapes in af Klint’s work and scientific diagrams in 19th century physicist Thomas Young‘s Lectures (1807). So began a four-year journey starting at the intersection of science and art that has culminated in a forthcoming paper in the journal Leonardo, making the case for the connection.

Af Klint was formally trained at the Royal Academy of Fine Arts and initially focused on drawing, portraits, botanical drawings, and landscapes from her Stockholm studio after graduating with honors. This provided her with income, but her true life’s work drew on af Klint’s interest in spiritualism and mysticism. She was one of “The Five,” a group of Swedish women artists who shared those interests. They regularly organized seances and were admirers of theosophical teachings of the time.

It was through her work with The Five that af Klint began experimenting with automatic drawing, driving her to invent her own geometric visual language to conceptualize the invisible forces she believed influenced our world. She painted her first abstract series in 1906 at age 44. Yet she rarely exhibited this work because she believed the art world at the time wasn’t ready to appreciate it. Her will requested that the paintings stay hidden for at least 20 years after her death.

Even after the boxes containing her 1,200-plus abstract paintings were opened, their significance was not fully appreciated at first. The Moderna Museum in Stockholm actually declined to accept them as a gift, although it now maintains a dedicated space to her work. It wasn’t until art historian Ake Fant presented af Klint’s work at a Helsinki conference that the art world finally took notice. The Guggenheim’s exhibit was af Klint’s American debut. “The exhibit seemed to realize af Klint’s documented dream of introducing her paintings to the world from inside a towering spiral temple and it was met roundly with acclaim, breaking all attendance records for the museum,” Lundgren wrote in her paper.

A pandemic project

Lundgren is the first person in her family to become a scientist; her mother studied art history, and her father is a photographer and a carpenter. But she always enjoyed art because of that home environment, and her Swedish heritage made af Klint an obvious artist of interest. It wasn’t until the year after she visited the Guggenheim exhibit, as she was updating her lectures for an astrophysics course, that Lundgren decided to investigate the striking similarities between Young’s diagrams and af Klint’s geometric paintings—in particular those series completed between 1914 and 1916. It proved to be the perfect research project during the COVID-19 lockdowns.

Lundgren acknowledges the inherent skepticism such an approach by an outsider might engender among the art community and is sympathetic, given that physics and astronomy both have their share of cranks. “As a professional scientist, I have in the past received handwritten letters about why Einstein is wrong,” she told Ars. “I didn’t want to be that person.”

That’s why her very first research step was to contact art professors at her institution to get their expert opinions on her insight. They were encouraging, so she dug in a little deeper, reading every book about af Klint she could get her hands on. She found no evidence that any art historians had made this connection before, which gave her the confidence to turn her work into a publishable paper.

The paper didn’t find a home right away, however; the usual art history journals rejected it, partly because Lundgren was an outsider with little expertise in that field. She needed someone more established to vouch for her. Enter Linda Dalrymple Henderson of the University of Texas at Austin, who has written extensively about scientific influences on abstract art, including that of af Klint. Henderson helped Lundgren refine the paper, encouraged her to submit it to Leonardo, and “it came back with the best review I’ve ever received, even inside astronomy,” said Lundgren.

Making the case

Young and af Klint were not contemporaries; Young died in 1829, and af Klint was born in 1862. Nor are there any specific references to Young or his work in the academic literature examining the sources known to have influenced the Swedish painter’s work. Yet af Klint had a well-documented interest in science, spanning everything from evolution and botany to color theory and physics. While those influences tended to be scientists who were her contemporaries, Lundgren points out that the artist’s personal library included a copy of an 1823 astronomy book.

Excerpt from Plate XXIX of Young’s Lectures Niels Bohr Library and Archives/AIP

Af Klint was also commissioned to paint a portrait of Swedish physicist Knut Angstrom in 1910 at Uppsala University, whose library includes a copy of Young’s Lectures. So it’s entirely possible that af Klint had access to the astronomy and physics of the previous century and would likely have been particularly intrigued by discoveries involving “invisible light” (electromagnetism, x-rays, radioactivity, etc.).

Young’s Lectures contain a speculative passage about the existence of a universal ether (since disproven), a concept that fascinated both scientists and those (like af Klint) with certain occult interests in the late 19th and early 20th centuries. In fact, Young’s passage was included in a popular 1875 spiritualist text, Unseen Universe by P.G. Tait and Balfour Stewart, that was heavily cited by Theosophical Society founder Helena Petrovna Blavatsky. Blavatsky in turn is known to have influenced af Klint around the time the artist created The Swan, The Dove, and Altarpieces series.

Lundgren found that “in several instances, the captions accompanying Young’s color figures [in the Lectures] even seem to decode elements of af Klint’s paintings or bring attention to details that might otherwise be overlooked.” For instance, the caption for Young’s Plate XXIX describes the “oblique stripes of color” that appear when candlelight is viewed through a prism that “almost interchangeably describes features in af Klint’s Group X., No. 1, Altarpiece,” she wrote

(a) Excerpt from Young's Plate XXX. (b) af Klint, Parsifal Series No. 68. (c and d) af Klint, Group IX/UW, The Dove, No. 12 and No. 13.

(a) Excerpt from Young’s Plate XXX. (b) af Klint, Parsifal Series No. 68. (c and d) af Klint, Group IX/UW, The Dove, No. 12 and No. 13. Credit: Niels Bohr Library/Hilma af Klint Foundation

Art historians had previously speculated about af Klint’s interest in color theory, as reflected in the annotated watercolor squares featured in her Parsifal Series (1916). Lundgren argues that those squares resemble Fig. 439 in the color plates of Young’s Lectures, demonstrating the inversion of color in human vision. Those diagrams also “appear almost like crude sketches of af Klint’s The Dove, Nos. 12 and 13,” Lundgren wrote. “Paired side by side, these paintings can produce the same visual effects described by Young, with even the same color palette.”

The geometric imagery of af Klint’s The Swan series is similar to Young’s illustrations of the production and perception of colors, while “black and white diagrams depicting the propagation of light through combinations of lenses and refractive surfaces, included in Young’s Lectures On the Theory of Optics, bear a particularly strong geometric resemblance to The Swan paintings No. 12 and No.13,” Lundgren wrote. Other pieces in The Swan series may have been inspired by engravings in Young’s Lectures.

This is admittedly circumstantial evidence and Lundgren acknowledges as much. “Not being able to prove it is intriguing and frustrating at the same time,” she said. She continues to receive additional leads, most recently from an af Klint relative on the board of the Moderna Museum. Once again, the evidence wasn’t direct, but it seems af Klint would have attended certain local lecture circuits about science, while several members of the Theosophy Society were familiar with modern physics and Young’s earlier work. “But none of these are nails in the coffin that really proved she had access to Young’s book,” said Lundgren.

Photo of Jennifer Ouellette

Jennifer is a senior writer at Ars Technica with a particular focus on where science meets culture, covering everything from physics and related interdisciplinary topics to her favorite films and TV series. Jennifer lives in Baltimore with her spouse, physicist Sean M. Carroll, and their two cats, Ariel and Caliban.

Did Hilma af Klint draw inspiration from 19th century physics? Read More »

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Rocket Report: China launches refueling demo; DoD’s big appetite for hypersonics

blue origin, china, hypersonic vehicles, launch, military space, NASA, rocket lab, rocket report, Science, Space, spacex, starship / /

We’re just a few days away from getting a double-dose of heavy-lift rocket action.

Stratolaunch’s Talon-A hypersonic rocket plane will be used for military tests involving hypersonic missile technology. Credit: Stratolaunch

Welcome to Edition 7.26 of the Rocket Report! Let’s pause and reflect on how far the rocket business has come in the last 10 years. On this date in 2015, SpaceX made the first attempt to land a Falcon 9 booster on a drone ship positioned in the Atlantic Ocean. Not surprisingly, the rocket crash-landed. In less than a year and a half, though, SpaceX successfully landed reusable Falcon 9 boosters onshore and offshore, and now has done it nearly 400 times. That was remarkable enough, but we’re in a new era now. Within a few days, we could see SpaceX catch its second Super Heavy booster and Blue Origin land its first New Glenn rocket on an offshore platform. Extraordinary.

As always, we welcome reader submissions. If you don’t want to miss an issue, please subscribe using the box below (the form will not appear on AMP-enabled versions of the site). Each report will include information on small-, medium-, and heavy-lift rockets as well as a quick look ahead at the next three launches on the calendar.

Our annual ranking of the top 10 US launch companies. You can easily guess who made the top of the list: the company that launched Falcon rockets 134 times in 2024 and launched the most powerful and largest rocket ever built on four test flights, each accomplishing more than the last. The combined 138 launches is more than NASA flew the Space Shuttle over three decades. SpaceX will aim to launch even more often in 2025. These missions have far-reaching impacts, supporting Internet coverage for consumers worldwide, launching payloads for NASA and the US military, and testing technology that will take humans back to the Moon and, someday, Mars.

Are there really 10? … It might also be fairly easy to rattle off a few more launch companies that accomplished big things in 2024. There’s United Launch Alliance, which finally debuted its long-delayed Vulcan rocket and flew two Atlas V missions and the final Delta IV mission, and Rocket Lab, which launched 16 missions with its small Electron rocket this year. Blue Origin flew its suborbital New Shepard vehicle on three human missions and one cargo-only mission and nearly launched its first orbital-class New Glenn rocket in 2024. That leaves just Firefly Aerospace as the only other US company to reach orbit last year.

DoD announces lucrative hypersonics deal. Defense technology firm Kratos has inked a deal worth up to $1.45 billion with the Pentagon to help develop a low-cost testbed for hypersonic technologies, Breaking Defense reports. The award is part of the military’s Multi-Service Advanced Capability Hypersonic Test Bed (MACH-TB) 2.0 program. The MACH-TB program, which began as a US Navy effort, includes multiple “Task Areas.” For its part, Kratos will be tasked with “systems engineering, integration, and testing, to include integrated subscale, full-scale, and air launch services to address the need to affordably increase hypersonic flight test cadence,” according to the company’s release.

Multiple players … The team led by Kratos, which specializes in developing airborne drones and military weapons systems, includes several players such as Leidos, Rocket Lab, Stratolaunch, and others. Kratos last year revealed that its Erinyes hypersonic test vehicle successfully flew for a Missile Defense Agency experiment. Rocket Lab has launched multiple suborbital hypersonic experiments for the military using a modified version of its Electron rocket, and Stratolaunch reportedly flew a high-speed test vehicle and recovered it last month, according to Aviation Week & Space Technology. The Pentagon is interested in developing hypersonic weapons that can evade conventional air and missile defenses. (submitted by EllPeaTea)

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ESA will modify some of its geo-return policies. An upcoming European launch competition will be an early test of efforts by the European Space Agency to modify its approach to policies that link contracts to member state contributions, Space News reports. ESA has long used a policy known as geo-return, where member states are guaranteed contracts with companies based in their countries in proportion to the contribution those member states make to ESA programs.

The third rail of European space … Advocates of geo-return argue that it provides an incentive for countries to fund those programs. This incentivizes ESA to lure financial contributions from its member states, which will win guaranteed business and jobs from the agency’s programs. However, critics of geo-return, primarily European companies, claim that it creates inefficiencies that make them less competitive. One approach to revising geo-return is known as “fair contribution,” where ESA first holds competitions for projects, and member states then make contributions based on how companies in their countries fared in the competition. ESA will try the fair contribution approach for the upcoming launch competition to award contracts to European rocket startups. (submitted by EllPeaTea)

RFA is building a new rocket. German launch services provider Rocket Factory Augsburg (RFA) is currently focused on building a new first stage for the inaugural flight of its RFA One rocket, European Spaceflight reports. The stage that was initially earmarked for the flight was destroyed during a static fire test last year on a launch pad in Scotland. In a statement given to European Spaceflight, RFA confirmed that it expects to attempt an inaugural flight of RFA One in 2025.

Waiting on a booster … RFA says it is “fully focused on building a new first stage and qualifying it.” The rocket’s second stage and Redshift OTV third stage are already qualified for flight and are being stored until a new first stage is ready. The RFA One rocket will stand 98 feet (30 meters) tall and will be capable of delivering payloads of up to 1.3 metric tons (nearly 2,900 pounds) into polar orbits. RFA is one of several European startups developing commercial small satellite launchers and was widely considered the frontrunner before last year’s setback. (submitted by EllPeaTea)

Pentagon provides a boost for defense startup. Defense technology contractor Anduril Industries has secured a $14.3 million Pentagon contract to expand solid-fueled rocket motor production, as the US Department of Defense moves to strengthen domestic manufacturing capabilities amid growing supply chain concerns, Space News reports. The contract, awarded under the Defense Production Act, will support facility modernization and manufacturing improvements at Anduril’s Mississippi plant, the Pentagon said Tuesday.

Doing a solid … The Pentagon is keen to incentivize new entrants into the solid rocket manufacturing industry, which provides propulsion for missiles, interceptors, and other weapons systems. Two traditional defense contractors, Northrop Grumman and L3Harris, control almost all US solid rocket production. Companies like Anduril, Ursa Major, and X-Bow are developing solid rocket motor production capability. The Navy previously awarded Anduril a $19 million contract last year to develop solid rocket motors for the Standard Missile 6 program. (submitted by EllPeaTea)

Relativity’s value seems to be plummeting. For several years, an innovative, California-based launch company named Relativity Space has been the darling of investors and media. But the honeymoon appears to be over, Ars reports. A little more than a year ago, Relativity reached a valuation of $4.5 billion following its latest Series F fundraising round. This was despite only launching one rocket and then abandoning that program and pivoting to the development of a significantly larger reusable launch vehicle. The decision meant Relativity would not realize any significant revenue for several years, and Ars reported in September on some of the challenges the company has encountered developing the much larger Terran R rocket.

Gravity always wins … Relativity is a privately held company, so its financial statements aren’t public. However, we can glean some clues from the published quarterly report from Fidelity Investments, which owns Relativity shares. As of March 2024, Fidelity valued its 1.67 million shares at an estimated $31.8 million. However, in a report ending November 29 of last year, which was only recently published, Fidelity’s valuation of Relativity plummeted. Its stake in Relativity was then thought to be worth just $866,735—a per-share value of 52 cents. Shares in the other fundraising rounds are also valued at less than $1 each.

SpaceX has already launched four times this year. The space company is off to a fast start in 2025, with four missions in the first nine days of the year. Two of these missions launched Starlink internet satellites, and the other two deployed an Emirati-owned geostationary communications satellite and a batch of Starshield surveillance satellites for the National Reconnaissance Office. In its new year projections, SpaceX estimates it will launch more than 170 Falcon rockets, between Falcon 9 and Falcon Heavy, Spaceflight Now reports. This is in addition to SpaceX’s plans for up to 25 flights of the Starship rocket from Texas.

What’s in store this year?… Highlights of SpaceX’s launch manifest this year will likely include an attempt to catch and recover Starship after returning from orbit, a first in-orbit cryogenic propellant transfer demonstration with Starship, and perhaps the debut of a second launch pad at Starbase in South Texas. For the Falcon rocket fleet, notable missions this year will include launches of commercial robotic lunar landers for NASA’s CLPS program and several crew flights, including the first human spaceflight mission to fly in polar orbit. According to public schedules, a Falcon 9 rocket could launch a commercial mini-space station for Vast, a privately held startup, before the end of the year. That would be a significant accomplishment, but we won’t be surprised if this schedule moves to the right.

China is dipping its toes into satellite refueling. China kicked off its 2025 launch activities with the successful launch of the Shijian-25 satellite Monday, aiming to advance key technologies for on-orbit refueling and extending satellite lifespans, Space News reports. The satellite launched on a Long March 3B into a geostationary transfer orbit, suggesting the unspecified target spacecraft for the refueling demo test might be in geostationary orbit more than 22,000 miles (nearly 36,000 kilometers) over the equator.

Under a watchful eye … China has tested mission extension and satellite servicing capabilities in space before. In 2021, China launched a satellite named Shijian-21, which docked a defunct Beidou navigation satellite and towed it to a graveyard orbit above the geostationary belt. Reportedly, Shijian-21 satellite may have carried robotic arms to capture and manipulate other objects in space. These kinds of technologies are dual-use, meaning they have civilian and military applications. The US Space Force is also interested in satellite life extension and refueling tech, so US officials will closely monitor Shijian-25’s actions in orbit.

SpaceX set to debut upgraded Starship. An upsized version of SpaceX’s Starship mega-rocket rolled to the launch pad early Thursday in preparation for liftoff on a test flight next week, Ars reports. The rocket could lift off as soon as Monday from SpaceX’s Starbase test facility in South Texas. This flight is the seventh full-scale demonstration launch for Starship. The rocket will test numerous upgrades, including a new flap design, larger propellant tanks, redesigned propellant feed lines, a new avionics system, and an improved antenna for communications and navigation.

The new largest rocket … Put together, all of these changes to the ship raise the rocket’s total height by nearly 6 feet (1.8 meters), so it now towers 404 feet (123.1 meters) tall. With this change, SpaceX will break its own record for the largest rocket ever launched. SpaceX plans to catch the rocket’s Super Heavy booster back at the launch site in Texas and will target a controlled splashdown of the ship in the Indian Ocean.

Blue Origin targets weekend launch of New Glenn. Blue Origin is set to launch its New Glenn rocket in a long-delayed, uncrewed test mission that would help pave the way for the space venture founded by Jeff Bezos to compete against Elon Musk’s SpaceX, The Washington Post reports. Blue Origin has confirmed it plans to launch the 320-foot-tall rocket during a three-hour launch window opening at 1 am EDT (06: 00 UTC) Sunday in the company’s first attempt to reach orbit.

Finally … This is a much-anticipated milestone for Blue Origin and for the company’s likely customers, which include the Pentagon and NASA. Data from this test flight will help the Space Force certify New Glenn to loft national security satellites, providing a new competitor for SpaceX and United Launch Alliance in the heavy-lift segment of the market. Blue Origin isn’t quite shooting for the Moon on this inaugural launch, but the company will attempt to reach orbit and try to land the New Glenn’s first stage booster on a barge in the Atlantic Ocean. (submitted by EllPeaTea)

Next three launches

Jan. 10: Falcon 9 | Starlink 12-12 | Cape Canaveral Space Force Station, Florida | 18: 11 UTC

Jan. 12: New Glenn | NG-1 Blue Ring Pathfinder | Cape Canaveral Space Force Station, Florida | 06: 00 UTC

Jan. 13: Jielong 3 | Unknown Payload | Dongfang Spaceport, Yellow Sea | 03: 00 UTC

Photo of Stephen Clark

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.

Rocket Report: China launches refueling demo; DoD’s big appetite for hypersonics Read More »

man-turns-irreversibly-gray-from-an-unidentified-silver-exposure

Man turns irreversibly gray from an unidentified silver exposure

Argyria, health, NEJM, Science, Silver / /

When an 84-year-old man in Hong Kong was admitted to a hospital for a condition related to an enlarged prostate, doctors noticed something else about him—he was oddly gray, according to a case report in the New England Journal of Medicine.

His skin, particularly his face, had an ashen appearance. His fingernails and the whites of his eyes had become silvery. When doctors took a skin biopsy, they could see tiny, dark granules sitting in the fibers of his skin, in his blood vessels, in the membranes of his sweat glands, and in his hair follicles.

A blood test made clear what the problem was: the concentration of silver in his serum was 423 nmol/L, over 40 times the reference level for a normal result, which is less than 10 nmol/L. The man was diagnosed with a rare case of generalized argyria, a buildup of silver in the body’s tissue that causes a blueish-gray discoloration—which is generally permanent.

When someone consumes silver particles, the metal moves from the gut into the bloodstream in its ionic form. It’s then deposited throughout the body in various tissues, including the skin, muscles, heart, lungs, liver, spleen, and kidneys. There’s some evidence that it accumulates in at least parts of the brain as well.

Discoloration becomes apparent in tissues exposed to sunlight—hence the patient’s notably gray face. Silver ions in the skin undergo photoreduction from ultraviolet light exposure, forming atomic silver that can be oxidized to compounds such as silver sulfide and silver selenide, creating a bluish-gray tinge. Silver can also stimulate the production of the pigment melanin, causing darkening. Once discoloration develops, it’s considered irreversible. Chelation therapy—generally used to remove metals from the body—is ineffective against argyria. That said, some case studies have suggested that laser therapy may help.

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Everyone agrees: 2024 the hottest year since the thermometer was invented

carbon dioxide, climate change, Earth science, global warming, greenhouse gasses, Science, temperature records / /

An exceptionally hot outlier, 2024 means the streak of hottest years goes to 11.

With very few and very small exceptions, 2024 was unusually hot across the globe. Credit: Copernicus

Over the last 24 hours or so, the major organizations that keep track of global temperatures have released figures for 2024, and all of them agree: 2024 was the warmest year yet recorded, joining 2023 as an unusual outlier in terms of how rapidly things heated up. At least two of the organizations, the European Union’s Copernicus and Berkeley Earth, place the year at about 1.6° C above pre-industrial temperatures, marking the first time that the Paris Agreement goal of limiting warming to 1.5° has been exceeded.

NASA and the National Oceanic and Atmospheric Administration both place the mark at slightly below 1.5° C over pre-industrial temperatures (as defined by the 1850–1900 average). However, that difference largely reflects the uncertainties in measuring temperatures during that period rather than disagreement over 2024.

It’s hot everywhere

2023 had set a temperature record largely due to a switch to El Niño conditions midway through the year, which made the second half of the year exceptionally hot. It takes some time for that heat to make its way from the ocean into the atmosphere, so the streak of warm months continued into 2024, even as the Pacific switched into its cooler La Niña mode.

While El Niños are regular events, this one had an outsized impact because it was accompanied by unusually warm temperatures outside the Pacific, including record high temperatures in the Atlantic and unusual warmth in the Indian Ocean. Land temperatures reflect this widespread warmth, with elevated temperatures on all continents. Berkeley Earth estimates that 104 countries registered 2024 as the warmest on record, meaning 3.3 billion people felt the hottest average temperatures they had ever experienced.

Different organizations use slightly different methods to calculate the global temperature and have different baselines. For example, Copernicus puts 2024 at 0.72° C above a baseline that will be familiar to many people since they were alive for it: 1991 to 2000. In contrast, NASA and NOAA use a baseline that covers the entirety of the last century, which is substantially cooler overall. Relative to that baseline, 2024 is 1.29° C warmer.

Lining up the baselines shows that these different services largely agree with each other, with most of the differences due to uncertainties in the measurements, with the rest accounted for by slightly different methods of handling things like areas with sparse data.

Describing the details of 2024, however, doesn’t really capture just how exceptional the warmth of the last two years has been. Starting in around 1970, there’s been a roughly linear increase in temperature driven by greenhouse gas emissions, despite many individual years that were warmer or cooler than the trend. The last two years have been extreme outliers from this trend. The last time there was a single comparable year to 2024 was back in the 1940s. The last time there were two consecutive years like this was in 1878.

A graph showing a curve that increases smoothly from left to right, with individual points on the curve hosting red and blue lines above and below. The red line at 2024 is larger than any since 1978.

Relative to the five-year temperature average, 2024 is an exceptionally large excursion. Credit: Copernicus

“These were during the ‘Great Drought’ of 1875 to 1878, when it is estimated that around 50 million people died in India, China, and parts of Africa and South America,” the EU’s Copernicus service notes. Despite many climate-driven disasters, the world at least avoided a similar experience in 2023-24.

Berkeley Earth provides a slightly different way of looking at it, comparing each year since 1970 with the amount of warming we’d expect from the cumulative greenhouse gas emissions.

A graph showing a reddish wedge, growing from left to right. A black line traces the annual temperatures, which over near the top edge of the wedge until recent years.

Relative to the expected warming from greenhouse gasses, 2024 represents a large departure. Credit: Berkeley Earth

These show that, given year-to-year variations in the climate system, warming has closely tracked expectations over five decades. 2023 and 2024 mark a dramatic departure from that track, although it comes at the end of a decade where most years were above the trend line. Berkeley Earth estimates that there’s just a 1 in 100 chance of that occurring due to the climate’s internal variability.

Is this a new trend?

The big question is whether 2024 is an exception and we should expect things to fall back to the trend that’s dominated since the 1970s, or it marks a departure from the climate’s recent behavior. And that’s something we don’t have a great answer to.

If you take away the influence of recent greenhouse gas emissions and El Niño, you can focus on other potential factors. These include a slight increase expected due to the solar cycle approaching its maximum activity. But, beyond that, most of the other factors are uncertain. The Hunga Tonga eruption put lots of water vapor into the stratosphere, but the estimated effects range from slight warming to cooling equivalent to a strong La Niña. Reductions in pollution from shipping are expected to contribute to warming, but the amount is debated.

There is evidence that a decrease in cloud cover has allowed more sunlight to be absorbed by the Earth, contributing to the planet’s warming. But clouds are typically a response to other factors that influence the climate, such as the amount of water vapor in the atmosphere and the aerosols present to seed water droplets.

It’s possible that a factor that we missed is driving the changes in cloud cover or that 2024 just saw the chaotic nature of the atmosphere result in less cloud cover. Alternatively, we may have crossed a warming tipping point, where the warmth of the atmosphere makes cloud formation less likely. Knowing that will be critical going forward, but we simply don’t have a good answer right now.

Climate goals

There’s an equally unsatisfying answer to what this means for our chance of hitting climate goals. The stretch goal of the Paris Agreement is to limit warming to 1.5° C, because it leads to significantly less severe impacts than the primary, 2.0° target. That’s relative to pre-industrial temperatures, which are defined using the 1850–1900 period, the earliest time where temperature records allow a reconstruction of the global temperature.

Unfortunately, all the organizations that handle global temperatures have some differences in the analysis methods and data used. Given recent data, these differences result in very small divergences in the estimated global temperatures. But with the far larger uncertainties in the 1850–1900 data, they tend to diverge more dramatically. As a result, each organization has a different baseline, and different anomalies relative to that.

As a result, Berkeley Earth registers 2024 as being 1.62° C above preindustrial temperatures, and Copernicus 1.60° C. In contrast, NASA and NOAA place it just under 1.5° C (1.47° and 1.46°, respectively). NASA’s Gavin Schmidt said this is “almost entirely due to the [sea surface temperature] data set being used” in constructing the temperature record.

There is, however, consensus that this isn’t especially meaningful on its own. There’s a good chance that temperatures will drop below the 1.5° mark on all the data sets within the next few years. We’ll want to see temperatures consistently exceed that mark for over a decade before we consider that we’ve passed the milestone.

That said, given that carbon emissions have barely budged in recent years, there’s little doubt that we will eventually end up clearly passing that limit (Berkeley Earth is essentially treating it as exceeded already). But there’s widespread agreement that each increment between 1.5° and 2.0° will likely increase the consequences of climate change, and any continuing emissions will make it harder to bring things back under that target in the future through methods like carbon capture and storage.

So, while we may have committed ourselves to exceed one of our major climate targets, that shouldn’t be viewed as a reason to stop trying to limit greenhouse gas emissions.

Photo of John Timmer

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.

Everyone agrees: 2024 the hottest year since the thermometer was invented Read More »