A well-timed smile can be the ultimate speed dating hack. Artificial intelligence-enhanced smiles during video chats led to greater romantic attraction, researchers report Oct. 28. Proceedings of the National Academy of Sciences.

Face filters, available to social media users around the world, can smooth out blemishes, whiten teeth and highlight hair. They can age you by decades or turn back time. They can even turn your face into a talking potato.

These digital manipulations are endlessly fun, but they can affect the way we see ourselves and others in ways we don’t fully understand. “The effect of these filters on human psychology remains largely unknown — even if billions of individuals use them,” says Pablo Arias-Sarah, an engineer and cognitive scientist at the University of Glasgow in Scotland.

Arias-Sarah and colleagues focused on a very subtle change in facial tuning—an increasingly easy change to smiling, expressions that can carry a great deal of social information. “Smiles are among the most emblematic and ubiquitous of human emotional expressions,” says Arias-Sarah, capable of communicating attraction, sincerity, competence, and confidence, perhaps even when forced (SN: 9/2/15).

In the four-minute video chats, the 31 participants either had their smiles slightly raised or lowered. For some of the conversations, both people’s smiles increased or decreased similarly. In others, the smiles were wrong, with one person’s smile facing up and the other facing down.

Timing was everything, it turns out. When two conversationalists increased their smiles, they reported higher levels of attractiveness than in other conditions, questionnaires after their conversation revealed. “Romantic attraction was affected by whether the participants were perceiving each other as smiling at the same time,” rather than just being attracted to the other person’s smile, says Arias-Sarah.

Showing that artificially enhanced smiles can affect romantic feelings raises broad questions about the ethical use of face-altering technology. After the speed dating experiment, the volunteers were told that their faces had been manipulated. But as this kind of technology permeates the digital world, these discoveries may not be so forthcoming.

Next, the researchers want to explore other digital transformations, changing gender, expressiveness, gaze or age, to study how they affect social interactions, such as job interviews.

The occasional sweet treat probably won’t ruin your health. But too much added sugar at a young age can increase the risk of health complications later in life.

Limiting added sugars during the first 1,000 days after conception — that is, during pregnancy and a baby’s first two years — reduces a child’s risk of developing diabetes and hypertension as adults, researchers report Oct. 31 in Science.

“In the first 1,000 days of life, the brain and body are preparing to complete development,” says Sue-Ellen Anderson-Haynes, a registered dietitian in Boston and a spokeswoman for the Academy of Nutrition and Dietetics. Nutrition during that time period is especially important, she says, because “everything the mother eats is converted into nutrients for the fetus.”

Current nutritional guidelines recommend that adults consume less than 40 grams of added sugars per day and that children under the age of 2 consume no added sugars. But by age 2, the average American child consumes about 29 grams of added sugars per day; an average adult consumes about 80 grams per day.

To study the effects of excess added sugars early in life, economist Tadeja Gracner of the University of Southern California in Los Angeles and colleagues took advantage of a natural experiment: the end of sugar rationing in the United Kingdom after World War II. While rationing was in effect, each person was allotted about 8 ounces (about 227 grams) of sugar per week. After sugar rationing ended in September 1953, daily sugar consumption for adults dropped to about 80 grams per day.

Although other foods were rationed during and after World War II, sugar intake increased more after rationing was lifted. Consumption of other rationed foods, such as cheese, milk and fresh fruit, remained relatively constant after rationing ended. Similarly, the end of butter rationing caused many families to switch from margarine, with its unsaturated fats, back to butter, so overall fat consumption did not increase significantly.

Gracner and her colleagues collected data from the UK Biobank on more than 60,000 participants born between October 1951 and March 1956. They divided the participants into two groups: Individuals born before July 1954 who experienced rationing of sugar in utero and early in life, and those born from July 1954 onwards who experienced no rationing.

People who experienced sugar rationing early in life were less likely to develop type 2 diabetes or high blood pressure in adulthood than people who did not experience sugar rationing, the team found. The risk of developing diabetes in people who dieted early in life was about 62 percent of the risk experienced by those whose sugar intake was not rationed; the risk of developing hypertension in those who experienced rationing was about 79 percent of the risk of those who did not.

Children who experienced sugar rationing early on were not immune to developing these chronic conditions, but it did tend to happen later in life: four years later on average for diabetes than the unrationed group, and two years later on average for high blood pressure of blood. Participants were also less likely to develop diabetes and hypertension if they experienced sugar rationing in utero, even if the participant did not experience rationing after birth.

Avoiding added sugars can be challenging, Gracner says, especially when so many foods for adults and young children contain them. “I don’t want parents to feel guilty about giving their kids sugar ever,” she says. More nutrition education and regulations on the marketing and pricing of sugary foods could help parents choose less sugar-laden options for their children and themselves, she says (SN: 16.4.19).

“I think we all want to improve our health and give our children the best start in life,” says Gracner. “The bottom line is that reducing added sugar early is one powerful step in that direction.”

Historians working with an artificial intelligence assistant have begun to trace the spread of astronomical thinking across Europe in the early 1500s.

The analysis contributes to challenging the idea of ​​the “lone genius” of scientific revolutions. Instead, it shows that knowledge of star positions was widespread and used in a variety of disciplines, researchers report Oct. 23 in Advances in science.

“We can see here the first formation of a proto-international scientific community,” says computer historian Matteo Valleriani of the Max Planck Institute for the History of Science in Berlin.

Valleriani and colleagues used AI to examine a digitized collection of 359 astronomy texts published from 1472, less than 20 years after the Gutenberg Bible was first printed, to 1650. (SN: 5/31/05).

These texts were used to teach introductory classes on geocentric astronomy—the view of the cosmos that places the Earth at the center and moves outward in sequential spheres. Knowing the positions of the stars was thought to be important for studying everything from medicine to Greek and Latin poetry, so introductory astronomy classes were mandatory for all students. Among other things, students learned to use the sun’s position in the zodiac constellations to figure out the date of an event that occurred in antiquity, before standardized calendars were common.

Studying these past texts can give historians an idea of ​​the background knowledge that most educated people had about the universe and how that understanding changed over time.

The data included 76,000 pages of text, images and numerical tables, many with different fonts, formats and layouts. A historian may be able to analyze a handful of books in a single career. But Valleriani and colleagues wanted to study them all.

“What we wanted to know, in general, is what students were learning in astronomy over these 180 years and across Europe,” says Valleriani. “That was humanly impossible.”

The team used machine learning to identify 10,000 unique number tables in textbooks. Next, they trained an AI model to recognize the individual numbers on the tables. “This was extremely difficult because the tables are not formatted in the same way,” says physicist and machine learning expert Klaus-Robert Müller of the Technical University of Berlin. “Everything is quite a mess.”

After the AI ​​had extracted all the numbers, it compared the different tables one by one and highlighted the similarities and differences. For example, some textbooks were essentially reprints of an earlier edition and their tables were almost identical. Others introduced new ideas or new ways to use astronomical data.

The AI ​​couldn’t tell the researchers what those similarities and differences meant (SN: 8/2/24). But it can give them a place to look for trends or moments of change.

“It’s going from using AI as a tool, to help do something I had envisioned, to using AI as a team member, suggesting new solutions that I couldn’t see,” says Valleriani.

A common story about astronomy in this time period is that individual heroes of science, such as Copernicus, Galileo, and Kepler, shocked the world by showing that the Earth is not the center of the universe.

But historians of science have moved away from the idea that science is run by such lone geniuses who make great discoveries. (SN: 3/5/16). These discoveries had social, political and cultural contexts and they had to be disseminated in some way to the wider culture.

“When you deal with the scientific revolution, the triumph of the Copernican worldview, we know the big names,” says computer scientist Jürgen Renn of the Max Planck Institute for Geoanthropology in Jena, Germany, who was not involved in the new work. “But in Europe, it was a broad movement. There were many participants.”

One of the team’s key findings is that textbooks printed in Wittenberg, Germany, in the 1530s were widely imitated elsewhere in Europe. Similar books that were sold in cities with larger markets, such as Paris and Venice, created a new, homogeneous approach to astronomy.

Valerian finds this ironic. Wittenberg is best known for being the town where Martin Luther started the Protestant Reformation, which split a new branch of Christianity from the Catholic Church.

“It sounds paradoxical,” says Valleriani. “While Wittenberg and the Protestant Reformation were dividing Europe … and creating the background against which the wars were fought, at the same time, Wittenberg was able to develop a scientific approach to the level of education that was actually taken up everywhere.”

There are limitations to this type of research, the team points out. Historical records are always incomplete, and historians must select a subset of that record to focus on. AI can’t account for that kind of selection bias. Human historians should always be part of the process, the researchers point out.

This work “shows how historians in the future can engage with AI methods and use them intelligently without this utopian or dystopian illusion that they can do the work for you,” says Renn. “They’re just a fantastic new tool that helps us understand history as a broad stream of human action and human thinking, rather than just a series of isolated events.”

Synthetic food colors—and their links to neurobehavioral issues in children—are having a moment.

Last month, California Governor Gavin Newsom signed into law the California School Food Safety Act, banning the state’s public schools from serving or selling foods containing six synthetic food dyes starting in 2028. Earlier this month in Michigan, protests erupted outside the Battle Creek headquarters of WK Kellogg Co., after the company drew fresh criticism for its broken commitment to remove synthetic food colors in American products, including cereal.

Meanwhile, the same dyes banned in California are still approved by the US Food and Drug Administration. The agency does not appear to be changing course, saying there is not enough evidence to prove that synthetic dyes cause problems such as ADHD, hyperactivity or lack of focus.

The list of foods that contain synthetic food coloring is long. And fueling the noise is the inability to distinguish the danger that a child has during their consumption. When federal and state guidelines don’t match, it can be tricky to find out which foods contain the colors and whether they should be avoided altogether.

Despite limited evidence of a neurobehavioral link, experts believe that some children may be more susceptible than others. Many experts are convinced that California’s law provides safety for the state’s public school students, and they hope the law could inspire other states to follow suit, forcing food manufacturers to reconfigure their recipes.

“I think it’s a great place to start because school is an environment where children should be able to focus. They need to be able to feel like they’re in control of their bodies,” says Melanie Benesh, vice president of government affairs for the Environmental Working Group in Washington, DC, a nonprofit corporation that sponsored the California School Food Safety Act. “It creates a better learning environment for everyone.”

Amidst this national conversation, Scientific news looked at how we got to this point and what science has to say about consuming synthetic food dyes.

What are synthetic food colors and why are they in our food?

Synthetic colors add color to food. Each of them has a unique molecular structure that absorbs specific frequencies of light, allowing people to perceive a rainbow of colors in soft foods. Beyond adding a splash of color, synthetic dyes are essentially useless. They do not help preserve food or add any nutritional value; their job is to seduce.

“A lot of these foods are candy, cereal—things that are marketed to kids,” Benesh says. When manufacturers use synthetic dye, it “makes their food more brightly colored, more attractive to children, and I think it helps them sell their products.”

Which products have synthetic dyes?

Foods with synthetic colors are not packaged with a warning label in the United States, so analyzing individual product labels is usually the only way to decipher exactly which food items contain which colors. If present, synthetic colors will be listed in the fine print of an item’s ingredient list, usually as the name of a color followed by a number (such as “Yellow 5”). If you’re looking to avoid dyes, here are some grocery store staples to watch out for:

• Baked goods such as cake mix, sugar cookies and gingerbread
• Snacks like Pop-Tarts, Cheetos and even some dried fruit
• Candies such as M&M’s, Skittles and Nerds
• Cereals such as Froot Loops, Trix and Lucky Charms
• Beverages and specialty drinks such as Electrolit, Pedialyte and Powerade

It is not only food products that contain synthetic food colors. Some eyeshadows, hair products and medications contain some of the dyes now banned in California.

When did scientists realize that synthetic dyes could be harmful?

Synthetic dyes have a long and troubled history. Lead chromate, arsenic, and additives made from coal tar were some of the first iterations, dealing a poisonous blow to consumers in the 19th and 20th centuries. In 1950, dozens of children became ill after consuming tainted Halloween candy with a dangerous color, Orange 1 (SN: 8/12/11).

Many modern synthetic dyes were invented at the same time; five of the six dyes banned in California were approved by the FDA in 1931. But their potential for harm was not widely discussed until the mid-1970s, when the idea of ​​a possible link between food coloring and childhood hyperactivity was discovered in public. says Mari Golub, a developmental neurotoxicologist at the University of California, Davis. A flurry of research ensued, but the FDA stuck to their guidelines.

However, some scientists say the connections are obvious. Over the past 50 years or so, a growing body of scientific research and anecdotal evidence has pointed to a link between certain synthetic food colors and neurobehavioral issues in children, which can manifest as mood swings, hyperactivity, and lack of attention. the focus.

So why did California ban the six synthetic dyes?

In 2021, California’s Office of Environmental Health Risk Assessment released a report that would help push the state to ban Blue 1, Blue 2, Green 3, Red 40, Yellow 5 and Yellow 6 in public schools .

The report’s authors looked at available research that investigated how synthetic food dyes affect children. They analyzed 25 clinical trial studies that compared periods of time when groups of children consumed foods colored with synthetic dyes to periods when they ate a placebo. In many of the trials, parents and teachers noted any behavior problems when they appeared. The report’s authors ultimately wrote that 16 of the studies showed a reliable link between behavioral outcomes and a child’s consumption of synthetic dyes.

But discovering a link doesn’t mean scientists can confirm that synthetic dyes are the direct cause of neurobehavioral issues. This is where animal studies come in.

Randomized studies with mice, rats, and rabbits have shown a clearer link between individual synthetic food dyes and neurobehavioral effects. Some animals exposed to synthetic dyes, such as those banned, may become hyperactive or show signs of memory loss.

While animal studies can be important tools for comparison, the amount of food coloring given to lab rats is difficult to compare with, say, how many Red 40 sprinkles are on a cupcake. It is difficult to count the individual sprinkles, chips and cookies in a child’s diet.

But animal studies have shown that colors affect animals neurologically, and they can help scientists determine which colors and individual doses start to create adverse effects, says Mark Miller, a pediatric environmental health physician at the California Office of Assessment of Environmental Health Hazards in Oakland, who worked. on assessment.

Why was the California decision controversial?

Not everyone supports California’s ban.

“Consistency in food regulations across states and federal agencies is critical to ensuring public confidence,” says Sean Taylor, an organic and biological chemist with the International Color Manufacturers Association in Washington, DC. He notes that the FDA reviewed scientific literature like Golub’s. the team did and concluded that there was no causal relationship between children consuming synthetic dyes and unwanted behaviors.

It’s hard to be specific when talking about the danger of food dyes because there isn’t much research out there to begin with. And technically, the FDA and the 2021 California Health Assessment don’t contradict each other: It finds no causal link; the latter finds an associative connection.

Because there has not been a study comparing one group of children on a diet without food dyes to another group of children consuming food concentrated with individual doses of synthetic dyes, it is difficult to identify a causal relationship.

“We don’t have the kind of data that would be the gold standard causal data,” says Amy Gilson, Deputy Director of External and Legislative Affairs at the California Office of Environmental Health Risk Assessment in Sacramento. It is unlikely that a black and white study will ever be published. But, says Gilson, “you don’t need to have all the causal data that someone would want to say, ‘Hey, you know there’s good evidence here. There is good science that tells us we need to take some action.’

A lucky alignment of two sun-studying spacecraft may have finally solved a decades-old solar mystery.

Data from NASA’s Parker Solar Probe and the European Space Agency’s Solar Orbiter suggest that plasma waves known as Alfvén waves inject energy into the solar wind as it leaves the sun’s outer atmosphere, potentially explaining why the solar wind is much hotter and faster than heliophysicists expect. , researchers report Aug. 29 at Science.

The findings provide “a very strong indication that Alfvén waves can heat and accelerate the solar wind,” says Jean Perez, a plasma physicist at the Florida Institute of Technology in Melbourne, who was not involved in the study.

Since the dawn of the Space Age, when robotic probes first left the atmosphere, scientists have known that the solar wind—a stream of charged particles released from the sun’s atmosphere—accelerates as it blows through the solar system.SN: 18.8.17). Theoretical calculations also show that the temperature of the solar wind should drop as it expands into space. This decline occurs, but measurements reveal that it occurs more slowly than predicted.

Observations from Earth have previously seen Alfvén waves oscillating near the sun. Such waves are oscillations in the magnetic fields of the plasma emanating from the sun. They are sometimes so large that they turn back on themselves in what are called “switchbacks” (SN 1/15/21). The observed Alfvén waves had just the right amount of energy to explain the two old head-scratchers about the speed and temperature of the solar wind, but direct evidence was still lacking.

Enter Parker Solar Probe and Solar Orbiter. In late February 2022, Parker was passing through a region about one-fifth the distance between the sun and Mercury, exactly where these keyed Alfvén waves ripple. Coincidentally, the Solar Orbiter flew through the same plasma stream just under two days later in roughly the orbit of Venus.

“You have these two spacecraft intercepting the same solar wind, allowing us to quantify the energy of these waves,” says Yeimy Rivera, a heliophysicist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.

Parker measured the plasma stream at about 1.4 million kilometers per hour, while Solar Orbiter found it was breaking away at 1.8 million km/h. The plasma in the Solar Orbiter was also 200,000 degrees Celsius, three times hotter than it should have been based on theoretical approximations. The Alfvén waves were temporally dispersed. That distribution would have injected exactly the right amount of energy into the solar wind to account for the increased speed and temperature measured by Solar Orbiter, Rivera and her colleagues calculate.

The effect is similar to clapping your hand in a wind tunnel, producing waves whose energy then mixes with the surrounding air, says heliophysicist Sam Badman, also of the Center for Astrophysics.

But not everyone is completely convinced that this mystery has been solved. It’s possible the team didn’t take into account the complexity of the solar wind, which means the two probes may not have captured the same plasma stream, some scientists say.

Rivera and Badman agree that such measurements are difficult, but think they have done multiple checks, such as finding the same amount of helium in the streams the spacecraft flew through, to verify their observations. In the future, the researchers say they hope to further validate their findings by exploring the detailed physics behind the transfer of energy between Alfvén waves and the solar wind.

The texture of mayonnaise inspires love and hate. Either way, it’s perfect for physics experiments.

The classic seasoning is useful for understanding how materials behave, not only when spread on sandwiches or spread on potato salads, but also when used in nuclear fusion experiments. Mechanical engineer Arindam Banerjee of Lehigh University in Bethlehem, Pa., and colleagues are studying phenomena that occur in both mayonnaise and melting experiments.

Mayonnaise’s behavior lies on the borderline between elastic and plastic. If moved gently, it returns to its original shape. This is elastic behavior. But throw it hard and it becomes plastic, meaning it permanently changes shape or breaks apart.

This elastic-to-plastic transition can also occur in experiments that use lasers to initiate nuclear fusion. In such experiments, lasers explode a metal capsule containing the fuel, raising pressures and temperatures so high that atomic nuclei in the fuel fuse together, releasing energy (SN: 16.2.24). Scientists hope to eventually use nuclear fusion as an energy source.

But it is difficult to study how materials behave in the extreme conditions required for melting. So, in their latest experiment, the scientists watched as the mayonnaise mixed with a gas—air—as they spun a wheel into which they had dropped the mayonnaise. The centrifugal force of the spinning wheel accelerated the mayonnaise into gas.

After the wheel stopped spinning, the scientists observed whether the orb returned to its original shape, changed shape, or split. This defined the boundary between elastic and plastic behavior, they reported in May Physical review E.

Mayonnaise and air are similar to the molten metal of a molten fuel capsule and the gas it contains. The molten capsule has some properties of a solid—like gooey mayonnaise, it doesn’t flow on its own—but it can shatter with enough force. If the metal becomes plastic before fusion occurs, the gas can escape, ruining the fusion effort.

Working with mayonnaise has one drawback. When you show up at the supermarket checkout line with 48 containers of mayonnaise, you’re going to attract attention. “Sometimes we get a lot of questions from grocery stores,” says Banerjee, “why are we buying so much mayonnaise.”

McCall: Argivoltaics is a term for the co-location of solar and agricultural activities, such as grazing, crop production and also ecological restoration.

Ravi: Argivoltaics has numerous benefits, both for farmers and solar developers.

McCall: If solar developers can show that they are using the land to the highest benefit, then they can use more land to develop more solar power. And then the next big one is the farmer and the land owner himself.

Ravi: Even if you lease your land for solar development, you may still have an income-generating activity such as growing crops or grazing sheep.

McCall: There are also local communities that can benefit from this. It could potentially create pollinator habitat or prairie restoration.

Choi: It used to be common practice for people to leave the ground bare for building solar, but that’s no longer the case.

Ravi: By covering the soil with vegetation, they can avoid erosion and use it as an opportunity to restore soil carbon.

McCall: Currently in the United States, there are approximately 530 (as of July 2024) argiovoltaic sites. It’s a roughly fifty-fifty split between pollinator habitats and solar grazing.

Choi: Right now, there’s a lot of focus on letting sheep graze under the solar panels because they don’t jump on the panels, they don’t like to chew the wires or anything.

Ravi: Integrating sheep grazing can also improve soil nutrients. So we just completed a five-year study in the middle US. Many of these areas have high carbon depletion due to intensive agriculture. And we actually found that managed sheep grazing can actually improve old soil carbon and nutrients.

McCall: And so, if it’s still the same cost as mowing the grass and we can provide a benefit to both the local grazers and potentially the environment, why not make it part of their standard practice somehow.

Ravi: So overall, there’s sort of an emerging consensus that solar grazing has some value in many of these landscapes. However, there are many unknowns when it comes to plant production.

McCall: Of those 570 argiovoltaic countries, only 40 are really focused on crop production. And a lot of those places are these small-scale research places.

Ravi: So the first thing to consider is which crops are best in which climates or geographical locations? This is a critical question because some crops can do well in shade, while some crops have significant yield losses in shade.

McCall: So even two varieties of the same tomato can respond very differently to the type of microclimate actually created by the solar panels. And then the weather patterns are not constant every year. So it’s very difficult to make some generalizations about when and where the crops would be available.

Choi: But in addition, crop production requires many modifications in engineering and design.

McCall: We actually have to raise the panels high enough so they don’t get shaded or we have to spread the panels much farther apart to actually get traditional farming equipment. Basically, all the changes that need to happen come with a cost trade-off or you’re getting less power. That’s why we’re seeing a little more hesitation in the US market.

McCall: We’re not going to do every system design everywhere, but where and when does it actually make sense and why would different stakeholders want to do it? As we see climate change such as reduced access to water and rising temperatures, there will be a need for solar integration. A prime example of this is wine grape production in California, where temperatures are currently too hot to actually produce certain grape varieties. And so they have to implement shadow structures. And so why not also produce solar power and make some money from that shade structure.

McCall: Eh, there’s also this broader need to grow food much closer to population centers.

Ravi: So, currently we are trying to understand which configurations of argivoltaic systems are suitable for our urban areas. We’ve set up an experimental system at Temple University’s Ambler Campus, which could fit into an abandoned parking lot or something else in a city. So the idea is to compare, like the solar groups that are affecting these cultures in different ways. It can actually improve yields of leafy greens. So we might be able to produce one more cycle of lettuce. But we still need to expand the study to other areas to see how the impacts are different. The next 10 years will provide a lot of information on different types of integration. This can be applied in different parts of the world.

Choi: And this is my dream. Where we can show a map and say, if we put panels here, the climate would be changed in such a way that we could grow this crop.

McCall: So this is not a one panacea solution that fits all. It really requires some thought. It really takes a lot of different stakeholders to get their perspective out there. But more solar production can also help meet climate change goals, and so it’s a matter of urgency to make sure we use this land to its highest benefit.

For the first time, scientists have measured a long-sought global electric field in Earth’s atmosphere. This field, called the ambipolar electric field, was predicted to exist decades ago but was never discovered until now.

“That’s the big noise,” says atmospheric scientist Glyn Collinson of NASA’s Goddard Space Flight Center in Greenbelt, Md.

The field is weak, just 0.55 volts – about as strong as a watch battery, Collinson says. But it is strong enough to control the shape and evolution of the upper atmosphere, features that may have implications for our planet’s suitability for life.

“It’s essential to the DNA of our planet,” says Collinson, who reported the new measurement in Nature August 28.

The existence of the ambipolar electric field was first predicted in the 1960s, at the dawn of the space age. Early spacecraft flying over Earth’s poles detected a supersonic outflow of charged particles from the atmosphere, called the polar wind.

The most reasonable thing to explain the fast wind would be an electric field in the atmosphere. The idea is that sunlight can strip electrons from atoms in the upper atmosphere. Those negatively charged electrons are light and energetic enough that they want to float around in space. The positively charged oxygen ions left behind are heavier and tend to sink under Earth’s gravity.

But the atmosphere wants to remain electrically neutral, maintaining an even balance between electrons and ions. The electric field is formed to keep the electrons attached to the ions and prevent them from escaping.

Once established, the field can act as a booster for lighter ions such as hydrogen, giving them enough energy to break free from Earth’s gravity and drift away as the polar wind. It can also pull heavier ions up into the atmosphere than they would otherwise reach, where other forces can also remove them into space.

That was the hypothesis. But until recently, the technology to detect the field did not exist.

“It really was thought impossible to do,” says Collinson. “[The field] so weak, it was just assumed you would never measure up.”

Collinson realized that this measurement had not been obtained after he and his colleagues tried to measure a similar field on Venus. A search for a paper reporting Earth’s field strength for comparison came up empty.

“It turned out, funny story, it’s never been done,” he says. “We were like, ‘Game on!'”

Collinson and colleagues developed a new instrument called a photoelectron spectrometer specifically to detect the electric field. The team mounted the spectrometer on a rocket called the Endurance, after the ship that carried Ernest Shackleton to explore Antarctica in 1914.

Reaching the launch site in Svalbard, Norway was a journey worthy of the rocket’s name. The team traveled by boat for 17 hours to reach the Svalbard archipelago, located just a few hundred kilometers from the North Pole. Several members of the team contracted COVID-19 along the way. And the war between Russia and Ukraine had started only a few months earlier.

“At the time, there was some nervousness about launching missiles,” says Collinson. “Polar bears were the fewest. We had war and pestilence.”

Two more days of storms kept the Endurance grounded. When the rocket finally launched on May 11, 2022, it went straight into the atmosphere at about 770 kilometers, measuring the energies of the electrons every 10 seconds. The entire flight lasted 19 minutes. In the end, the rocket was thrown into the Greenland Sea.

Endurance measured a difference in electrical potential of 0.55 volts between altitudes of 248 kilometers and 768 kilometers—just enough to explain the polar wind on its own, without any other atmospheric effects.

The measurement is solid and exciting, says planetary scientist David Brain of the University of Colorado Boulder, who was not involved in the new work. But it’s just one data point from a rocket. “I think this result is a really big result that argues that there should be more measurements like this,” he says.

Collinson agrees. He and his colleagues recently won NASA approval for a follow-up rocket—this time called Resolute, for an Arctic exploration ship that launched in 1850.

Because the ambipolar electric field helps control how quickly a planet’s atmosphere escapes into space, it probably plays a role in making a planet hospitable to life, Collinson says. Scientists think Mars was once more like Earth, but lost much of its atmosphere to space over time (SN: 11/27/15). Venus may once have been much wetter than it is today (SN: 8/1/17).

Both of these planets also have ambipolar electric fields, but they may have been better off without them.

“If this process didn’t exist on Venus and Mars, then I think it’s possible that Venus and Mars would have lost less oxygen, and therefore less water,” says Brain.

Earth’s ambipolar electric field helps push its oxygen into space, too. But Earth has one major advantage over Mars and Venus: a global magnetic field to direct charged particles around the planet. “The electric field is the engine that makes the particles move,” says Brain. “The magnetic field is a kind of path along which particles move.” The Earth’s magnetic field means that oxygen can only escape near the poles, and not from every part of the atmosphere. This may help explain why Earth has retained its habitable atmosphere for much longer than Venus or Mars.

“Basically, what makes a planet habitable is going to be a lot of things,” Collinson says. “But I think comparing these different energy fields across different planets is one way to answer the question, why is Earth habitable? Why are we here?”

Scientific watchmakers have created a prototype of a nuclear clock, hinting at future possibilities for using atomic nuclei to make precise time measurements and make new tests of fundamental theories of physics.

While the definition of “watch” is scientifically nebulous, the prototype has yet to be used to measure time. So it should technically be called the “frequency standard,” says physicist Jun Ye. But the work brings scientists closer to a nuclear clock than ever before. “For the first time, all the essential ingredients for a working nuclear clock are contained in this work,” says Ye, of JILA in Boulder, Colo.

While atomic clocks measure time based on electrons bouncing between energy levels in atoms, nuclear clocks measure time based on the energy levels of atomic nuclei. A certain frequency of laser light is needed for an atom or an atomic nucleus to make such a jump. The electromagnetic wave motion of that light can be used to tell time.

Nuclear clocks would keep time using a variety of the element thorium, called thorium-229. Most atomic nuclei make energy jumps that are too large to be triggered by a tabletop laser. But thorium-229 has two energy levels that are close enough to each other that the transition between these two levels can serve as a clock.

Now, researchers have pinpointed the frequency of light needed to initiate that jump. It’s 2,020,407,384,335 kilohertz, Ye and colleagues report on Sept. 5. Nature.

Most importantly, measurement has an uncertainty of 2 kilohertz. This is more than a million times the accuracy of the previous best measurement. And it’s more than a billion times the accuracy with which this frequency was known just over a year ago, highlighting multiple successive developments.

The enhancement depends on a component called a frequency comb (SN: 10/5/18). An essential component of many atomic clocks, a frequency comb creates a series of discrete frequencies of light. The use of a thorium-229 frequency comb has been a major research goal for some scientists (SN: 6/4/21). In the new work, Ye and colleagues compared the ticking of the nuclear clock with that of an atomic clock of a known frequency.

“This is something that will be important as a scientific application for tests of fundamental physics,” says physicist Ekkehard Peik of the National Institute of Metrology in Braunschweig, Germany, who was not involved in the new research.

In the future, such comparisons can be used to search for strange physical effects, such as shifting values ​​of fundamental constants (SN: 11/2/16). These are numbers that – as the name implies – are believed to be eternally fixed.