Latest from Scientific American
Scientific American
8 hours ago
- General
- Scientific American
Math Puzzle: Burn the Ropes
A classic puzzle conundrum goes like this: You're in a room with two ropes and a box of matches. Each rope takes exactly an hour to burn all the way across, but it might burn faster through some sections and slower through others. Find a way to measure exactly 15 minutes.
Scientific American
15 hours ago
- Climate
- Scientific American
Hurricane Forecasters Lose Crucial Satellite Data, with Serious Implications
On television broadcasts and forecast maps, hurricanes appear as two-dimensional swirling vortices, belying their extremely complex three-dimensional structure. Being able to peer past the tops of clouds to see what's happening inside a storm is critical for forecasting—particularly for catching one that is about to rapidly intensify into something more dangerous. But a key source of data that provide an x-ray-like view of that structure will shut down by June 30, just before hurricane season tends to kick into high gear. 'It's certainly one of the more important data sources that we have because it provides a unique dataset,' says James Franklin, former chief of the National Hurricane Center's (NHC's) Hurricane Specialist Unit. 'It's the only way really to see through clouds and get a sense of the organizational structure of the core of a developing cyclone.' Having that information can alert forecasters to rapid intensification or other major changes hours before they become apparent in other data—providing crucial time to warn people in harm's way. This view into storm structure comes from sensors onboard Defense Meteorological Satellite Program (DMSP) satellites. Those data will no longer be taken up, processed and sent out to the National Hurricane Center or other non-Department of Defense users. The exact reasons for the shutoff are unclear but appear to be related to security concerns. On supporting science journalism If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today. 'The timing [of the shutdown] could not be worse as far as hurricane season is concerned,' and it comes along with other recent cuts and limitations to the National Oceanic and Atmospheric Administration, says Kim Wood, an atmospheric scientist at the University of Arizona. What do microwave data tell us about hurricanes? Satellites orbiting the Earth gather data in multiple wavelengths of light: visible, infrared, microwave, and so on. Each provides different kinds of information. Most people typically see images of hurricanes in the visible part of the electromagnetic spectrum, but the storms also emit microwaves. 'Everything is emitting microwaves,' Wood says. 'We're currently emitting microwaves sitting here. And it's because our temperatures are above absolute zero.' Microwaves are useful in monitoring hurricanes, Wood says, 'because the waves are so long they get through the tops of the clouds.' This lets forecasters see a storm's inner workings—particularly changes to its eye and eye wall (the circle of clouds that surround the eye and make up the strongest part of the storm). Such changes can indicate if a hurricane is strengthening or weakening. This is a particularly useful tool for monitoring storms at night, when visible satellite imagery is unavailable. Though infrared data are available at night, microwave data have 16 times their resolution, Wood says. Being able to watch a storm overnight can help avoid what Franklin calls a 'sunrise surprise'—when forecasters get the first visible imagery at daylight and find that the storm has become much stronger or better organized than they had expected. Microwave imagery is particularly useful for catching rapid intensification—defined as when a storm's winds jump by at least 35 miles per hour in 24 hours. Forecasters using microwave data can catch the process and warn people faster than they could otherwise. This was the case with Hurricane Otis in 2023, which was the first known Category 5 Pacific hurricane ever to make landfall and caused significant devastation. Microwave 'satellite imagery clued us in to the potential for this system to be really strong,' Wood says. Microwave data are also extremely useful in locating the center of weaker storms. These storms tend to lack a central eye and eye wall, and clouds higher in the atmosphere can obscure where those located lower down are circulating in visible imagery. Knowing where the center of the storm lies is important information to feed into hurricane models that forecast where the storm will go. Feeding microwave data into models can improve the accuracy with which they determine the position of the center of a storm by about 60 miles, Franklin says—noting that an incorrect position is 'going to cascade or leak into your track forecast.' This means that meteorologists who lack microwave imagery may not be able to forecast where a storm will make landfall as accurately as those who have it. Where do microwave data come from, and why were they cut? Because the microwaves emitted from Earth's surface and atmosphere are very weak, they can only be detected by satellites in very low-Earth orbit, Wood says. (The geostationary satellites that provide visible imagery orbit farther out. To have a sensor big enough to detect microwaves from their position, they would need to be the size of the Death Star, Wood says.) But because those microwave-detecting satellites orbit so close to Earth, they see less of it at any given time than geostationary satellites do—so more of them are needed to adequately monitor the planet. And there are longer time gaps between when a microwave-detecting satellite 'revisits' the same spot. That means microwave data are already limited. There are currently six satellites providing that information for U.S. weather forecasting purposes, and they are only useful for hurricanes if they serendipitously pass overhead at the right time. But now three of them are about to be turned off. 'That's a big drop in the availability of this tool,' Franklin says. The data that are about to be lost come from what are called Special Sensor Microwave Imager Sounder (SSMIS) sensors onboard three DMSP satellites. The exact reason for the shutoff is unclear, though some reports have cited security concerns. It does not appear that the concerns are with sharing the data themselves or with funding the collection and dissemination of that information. In an e-mail to Scientific American, a spokesperson for the U.S. Space Force wrote that 'DMSP satellites and instruments are still functional' and that DOD users will continue to receive the data. They referred further questions about the decision to the U.S. Navy, which had not replied to requests for comment by press time. In an e-mail to Scientific American, Maria Torres, a spokesperson for the NHC, wrote that "the DMSP is a single dataset in a robust suite of hurricane forecasting and modeling tools in the NWS portfolio.' She cited other satellites, ocean buoys and the Hurricane Hunter flights, among other tools. 'NOAA's data sources are fully capable of providing a complete suite of cutting-edge data and models that ensure the gold-standard weather forecasting the American people deserve,' Torres wrote. There are other satellites that could theoretically provide microwave data—including a recently launched DOD satellite—but there has been no discussion of making those data broadly accessible, Wood says. And because forecasting models and other systems are geared toward the existing data, it is not simple to use a new data source as a substitute. 'It's one thing for a satellite to exist,' Woods say. 'It's another thing for us to be able to access it.' What we can expect this hurricane season The loss of these data is most concerning when it comes to storms that are relatively far out in the ocean (beyond the range of Hurricane Hunter aircraft) and to storms in the Pacific Ocean, where fewer such missions are flown. There are typically more monitoring flights for storms that are a threat to the U.S., particularly as they get close to land. But two thirds of all hurricane advisories are issued based solely on satellite data, Franklin says. The loss of these data alone would be extremely concerning for forecast accuracy this hurricane season—but it comes on top of the broader cuts that have already been made to the National Weather Service and NOAA. For example, there may be fewer launches of the weather balloons that help illuminate how the larger atmospheric environment will steer a storm. And it is unclear if Hurricane Hunter flights might be affected. 'Losing this data is worse than it might have been a year ago,' Wood says. 'It's pretty much guaranteed that there will be some forecast this year where significant intensification, most likely of a tropical storm [to a hurricane], is missed by six to 12 hours because these data weren't available,' Franklin says. If it is a Pacific Coast storm, this could be devastating for communities in the way. And even if it is out at sea, it is a big concern for mariners. 'Ships go down in hurricanes,' Franklin says. All in all, 'there are a lot of things that are working against forecasting' this year, he says.
Scientific American
20 hours ago
- Science
- Scientific American
This Solar-Powered Slug Steals Photosynthetic Machinery for Emergency Food
' Solar-powered' sea slugs have specialized depots in their cells that store photosynthetic equipment looted from algae, a study reports. These depots provide just the right chemical environment to keep the stolen apparatus, called chloroplasts, alive and working to turn sunlight into nutrients. 'It was the wildest thing that we had seen,' says study co-author Nicholas Bellono, a biologist at Harvard University in Cambridge, Massachusetts. The authors also found that, in lean times, the slugs can raid these compartments to consume chloroplasts. The compartment 'is basically like a moving refrigerator of chloroplasts where, after a period of starvation, the slugs can switch from storage to consumption to survive', Bellono says. On supporting science journalism If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today. The findings were published in Cell. Green grazer Scientists discovered decades ago that certain species of sea slug store chloroplasts from the algae they eat, a diet that can turn the slugs bright green. But no one understood how the slugs keep these foreign organelles alive without the support of the rest of the algal cell. Bellono and his team added chemical tags to proteins newly made by the slugs' own cells. They found that most of the proteins in a slug's chloroplasts were made by the slug — not by the original algae. That meant the slug was helping to maintain the chloroplasts. When the scientists looked at the chloroplasts under a microscope, they found that the organelles were housed in special compartments in the slugs' guts. Each compartment was surrounded by a membrane that tested positive for markers typically found in cellular structures called phagosomes, which fuse with other structures called lysomes to digest unneeded organelles. The researchers named this structure the kleptosome, after a Greek word that means to steal. Life of crime The team also found that these organelles contained ion channels — receptors that convert chemical messages into electrical signals. Among them is one called P2X4, which opens in response to the presence of ATP, an energy-carrying molecule produced during photosynthesis. When Bellono and his team blocked this channel in slugs' kleptosomes, oxygen production from photosynthesis dropped, showing that the kleptosome is actively involved in keeping the chloroplasts functioning. Having discovered the existence of the kleptosome, the researchers wondered whether it helps the slugs to resist starvation. They compared the solar-powered slug Elysia crispata with Aplysia californica, a non-photosynthetic slug that lacks kleptosomes. Aplysia died after three to four weeks without food, whereas Elysia could survive for up to four months. Yet, after four weeks, the Elysia slugs lost their green colour, turned orange — just as leaves do in autumn — and stopped photosynthesizing. Microscopy revealed that the Elysia 's kleptosomes had begun fusing with lysosomes and that the colour change was caused by the degradation of the chloroplast. The study is 'remarkable,' says cell biologist Elena Oancea at Brown University in Providence, Rhode Island. Studying the molecular and cellular processes of creatures as small as sea slugs is extremely challenging, she says. 'It takes a lot of courage to do that.' The discovery of the kleptosome could help to answer broader questions about organelle evolution and other cellular processes that we don't understand yet, Oancea says. All life is built on cells, she adds: 'It's the basic principle of nature.'
Scientific American
a day ago
- Health
- Scientific American
Meditation's Benefits Stretch Beyond the Person Who Meditates
Listening to the daily news, with stories of war and conflict, can be disheartening. Unsurprisingly, data suggest that a majority of Americans feel exhausted and hopeless when they think about politics. Some psychologists have argued that Americans suffer from a sort of learned helplessness —the sense that nothing we do will make a difference—from hearing about violence such as mass shootings. We feel the pain of events in the news cycle but see ourselves as powerless to stop them. In terms of coping with these events, meditation could help in more ways than one. The power of meditation for cultivating personal well-being is hardly a secret. For more than 20 years, neuroscientists have been documenting how mindfulness meditation can help people cultivate calm and improve their mood, among other benefits. Some recent research suggests it can also help people experience deeper psychological transformation, allowing regular practitioners to reach important insights about themselves and their world. But there's another consequence of meditation that people do not always anticipate. Despite the ways in which wellness movements have emphasized a highly individualistic way of thinking about meditation and self-care, meditation can also help care for and support others. On supporting science journalism If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today. When one person takes the time to regularly be still and attend to a specific cue, such as their breath or a mantra, their practice can have spillover benefits for the people around them. It's an idea that several studies have explored to date and one that dovetails with recent investigations into what scientists call the social ripple effect, or the idea that one person's behavior, mood or attitudes can spread throughout a community. It is also a potent reminder of how bringing a spirit of calm and compassion towards oneself may translate into something beneficial to those around us. Some meditators propose that if enough people had a regular practice, the result would be a world enriched with calm and compassionate people. And there's science to support that idea. Research demonstrates that people who meditate show increased positivity toward others. For instance, training in meditation is linked to increased sensitivity to and engagement with human suffering and an increased tendency toward altruism. Similarly, meditation interventions aimed at increasing kindness are associated with reduced bias toward numerous 'others,' including ethnic out-groups, people experiencing homelessness and people who face stigma because of their weight. In one classic study, 20 people received eight weeks of meditation training, and another 19 were put on a wait list for training. Afterward each participant came to an appointment and had to wait in a crowded room with just one available seat. When a researcher came in, pretending to be another person with an appointment who had a seemingly painful broken foot, the people who had received meditation training were significantly more likely to give up their seat than study participants who had not received this training. So why might one person's meditation practice benefit the people around them? There are many plausible mechanisms. For one, as meditation trains participants to be aware in the present moment, it may promote sensitivity to others' perspectives and emotions. Another possibility is that we sometimes dismiss others' pain because it will cause us discomfort—but meditation can help practitioners better cope with negative emotions, making it less painful to engage with and respond to others' suffering. In line with these ideas, researchers published findings in 2023 that showed that meditation increased people's concern for the suffering of others—and that, by comparison, people without this practice were more oriented to their own distress. Meditation may also help people develop strong interpersonal relationships. The practice may leave people in a better mood overall and build up their emotional control, both of which could improve their interactions with others. Last spring a study that compared 47 physicians who were trained in meditation with 47 who did not have this training found that doctors in the meditation group were less anxious about communicating with their patients and reported having more trust in others. Critically, the meditating participants were also less likely to practice defensive medicine, in which doctors make health care choices based on fear of litigation instead of best practice. The higher-quality social interactions that emerged with meditation training seemed to improve doctor-patient interactions and ultimately the care that doctors provided to their patients. It's possible that the meditators' improved relationships and interactions have even broader benefits. Research on a phenomenon called the social ripple effect suggests a person's attributes can spread through and beyond their social network. For example, in a study published in 2024, when researchers wanted to find the best way to deliver an intervention aimed at reducing newborn infant mortality to people living in 176 isolated villages in the Honduran highlands, they provided information on prenatal health, safe delivery and newborn care to a subset of people in these communities who had strong social connections. Teaching those socially influential individuals triggered a knowledge spillover by two degrees of separation, such that friends of friends of these villagers knew at least some of the health information two years after the researchers' initial efforts. The researchers thus found a way to target a subset of the population while reaching far more. Although social ripple studies have yet to explore meditation, it's possible a similar phenomenon occurs. Some experienced meditators have argued that cultivating a state of compassion in oneself helps us bring that attitude toward others. Perhaps, in turn, they pass some calm and compassion along too. Whatever may be at play, the science of meditation's social consequences are heartening. Often, the challenges of the world can feel overwhelming, and one person's actions may seem to make very little difference. But this research is a reminder that when we improve our own well-being, we can also improve the lives of others. The benefits of just one person cultivating peace and compassion may have a cascading impact.
Scientific American
a day ago
- Science
- Scientific American
New Proof Dramatically Compresses Space Needed for Computation
Once upon a time computers filled entire rooms, reading numbers from spinning tapes and churning them through wires to do chains of basic arithmetic. Today they slip into our pockets, performing in a tiny fraction of a second what used to take hours. But even as chips shrink and gain speed, theorists are flipping the question from how much computation space we can pack into a machine to how little is enough to get the job done. This inquiry lies at the heart of computational complexity, a measure of the limits of what problems can be solved and at what cost in time and space. For nearly 50 years theorists believed that if solving a problem takes t steps, it should also need roughly t bits of memory—the 0s and 1s that a machine uses to record information. (Technically, that equation was t/ log(t), but for the numbers involved log(t) is typically negligibly small.) If a task involves 100 steps, for instance, you'd expect to need at least 100 bits, enough to diligently log each step. Using fewer bits was thought to require more steps—like alphabetizing your books by swapping them one by one on the shelf instead of pulling them all out and reshelving them. But in a surprising finding described this week at the ACM Symposium on Theory of Computing in Prague, Massachusetts Institute of Technology computer scientist Ryan Williams found that any problem solvable in time t needs only about √ t bits of memory: a 100-step computation could be compressed and solved with something on the order of 10 bits. 'This result shows the prior intuition is completely false,' Williams says. 'I thought there must be something wrong [with the proof] because this is extremely unexpected.' The breakthrough relies on a 'reduction,' a means of transforming one problem into another that may seem unrelated but is mathematically equivalent. With reductions, packing a suitcase maps onto determining a monthly budget: the size of your suitcase represents your total budget, pieces of clothing correspond to potential expenses, and carefully deciding which clothes can fit is like allocating your budget. Solving one problem would then directly solve the other. This idea is at the core of Williams's result: any problem can be transformed into one you can solve by cleverly reusing space, deftly cramming the necessary information into just a square-root number of bits. Thus, the original problem must be solvable with this compact container. On supporting science journalism If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today. 'This progress is unbelievable,' says Mahdi Cheraghchi, a computer scientist at the University of Michigan. 'Before this result, there were problems you could solve in a certain amount of time, but many thought you couldn't do so with such little space.' Williams's finding, he adds, is 'a step in the right direction that we didn't know how to take.' While computers have continued to shrink, our theoretical understanding of their efficiency has exploded, suggesting that the real constraint is not how much memory we have but how wisely we use it.
