2026-08-18の世界

A tiny worm with no mouth and no gut just changed how scientists think about plastic in nature. Researchers at the Max Planck Institute for Marine Microbiology in Bremen, Germany, studied a strange marine worm called Olavius algarvensis. The worm is about two centimeters long. It cannot eat food directly, so it farms bacteria under its skin and slowly digests them instead. One of these bacteria stores large amounts of carbon as a natural bioplastic called PHA, short for polyhydroxyalkanoate. Scientists once believed only microorganisms could break PHA down. Led by Caroline Zeidler and Nicole Dubilier, the team found a special enzyme inside the worm that turns PHA into small molecules the worm can use as food. High-resolution images showed the enzyme appears exactly where the worm digests its bacteria. The researchers then found similar enzymes in more than 66 animal species across nine groups, including starfish, earthworms, sponges, and springtails. That surprising pattern suggests many animals may have quietly been eating nature's own original bioplastic for hundreds of millions of years, long before humans invented plastic at all.

Some swimmers wait years for one world record, but Kate Douglass got two in a single day. On August 15, at the Pan Pacific Championships in Irvine, California, the 24-year-old American swam the 50-meter freestyle in 23.49 seconds during the morning heats, breaking the world record. Nine hours later, in the evening final, she lowered her own new mark again, touching the wall in 23.19 seconds. Her training partner and teammate, Gretchen Walsh, finished second in that final with 23.74 seconds. The record had bounced between the two swimmers all summer. Douglass first set it at 23.59 seconds in June, only for Walsh to lower it to 23.55 seconds nine days later in Rome. After her stunning final swim, Douglass said she had to do a few double takes because the time seemed too fast to be real. She left the meet with six medals overall, four of them gold, including a world record in the mixed 4x100-meter medley relay. Her coaches and teammates said the rivalry between Douglass and Walsh keeps pushing both of them to swim faster than anyone thought possible.

Glaciers hide dangerous cracks that are almost impossible to see from the surface, but one long cable just made them visible. Researchers at ETH Zurich, led by assistant professor Thomas Hudson, laid a single fiber-optic cable across a crevasse field on the Gorner Glacier in Switzerland. A device called an interrogator sent pulses of light down the cable. Every time a hidden crack opened or shifted deep in the ice, tiny vibrations changed how the light reflected back, letting the team map cracks up to 25 meters below the surface. The results published in the journal Science Advances surprised even the researchers. About 8 percent of the ice they studied turned out to be fractured or hollow, far more than the team expected. Hudson said a single cable like this can replace more than 100 traditional seismometers, since it gives hundreds of measurement points at once. Because water flowing into these hidden cracks can speed up how fast a glacier slides and melts, understanding them matters for predicting sea level rise. The team hopes this cheap, easy-to-carry method can soon help monitor much larger ice sheets in Greenland and Antarctica, where melting ice already affects coastlines around the world.

Even without a single word, music can make your brain build a story, and scientists just watched it happen. Researchers at Princeton University, led by music professor Elizabeth Margulis and neuroscientist Uri Hasson, played 10 unfamiliar instrumental pieces and 10 spoken stories to volunteers while scanning their brains with fMRI. After each excerpt, listeners described whatever story or scene came to mind. Remarkably, 71 percent of participants imagined very similar stories when they heard the exact same piece of music, even though nobody had heard any of the pieces before. Brain scans showed that music and speech activated strikingly similar regions, including areas linked to imagination, memory, and meaning, known together as the default mode network. Margulis said listeners were not just reacting to abstract sound but were engaging in a very concrete meaning-making process. The findings suggest that music and language may tap into the same deep mental machinery for understanding the world, something humans have likely relied on for as long as they have told stories. The researchers hope the discovery could eventually support new approaches for treating conditions like depression and anxiety, since music may open some of the same emotional pathways as spoken language.

A total solar eclipse can look different depending on where you stand to watch it, and a photo taken in Spain proves it beautifully. On August 12, the moon's shadow swept across Greenland, Iceland, and northern Spain, blocking the sun completely for a few minutes. From the town of Benavente in Spain, the sun was already low, setting near the horizon, when totality began. NASA featured a striking image of that moment as its Astronomy Picture of the Day on August 17. Instead of the usual white ring, the sun's outer atmosphere, called the corona, glowed a warm gold. Two things caused the unusual color. First, because the sun sat so low in the sky, its light traveled through a much thicker layer of air, and that extra air scattered away more blue light, the same reason sunsets often turn orange. Second, smoke drifting from nearby wildfires added another layer that scattered even more blue light. Interestingly, a bright loop of glowing hydrogen gas at the sun's edge, called a prominence, kept its usual pink color even as the corona around it turned gold, showing the golden effect was specific to the scattered corona light.

More than ten million years ago, a lake bigger than any today covered much of northern South America, and its deadliest hunter was not a mammal at all. A new study led by Oscar Wilson, a postdoctoral researcher at the University of Helsinki, examined fossil bones from three species of large hoofed mammals found in the La Venta region of Colombia's Huila department. The bones, dated to between 10.5 and 16 million years old, carried bite and tooth marks, the clearest direct evidence scientists have of predator-prey interactions from that time. Working with colleagues from Colombia, France, Argentina, Canada, and the United States, Wilson concluded that crocodylians, not mammalian predators, dominated the hunting of large prey. The biggest of them all was Purussaurus neivensis, a relative of today's caimans that grew up to seven meters long and weighed around 1,800 kilograms. Wilson said there was so much prey available that mammal predators alone could not have eaten it all, and that the frequency of marks likely made by Purussaurus suggests it was a major predator in these tropical wetland ecosystems. The findings, published in the Journal of Vertebrate Paleontology, suggest this giant crocodylian may have shaped how large the local herbivores could grow.

Finding your way in space usually means relying on GPS or a check-in with mission control, but NASA just proved spacecraft can do it alone. On August 17, NASA announced results from FALCON, short for Fast Autonomous Lost-in-space Catalog-based Optical Navigation, tested aboard the four-satellite Starling swarm in low Earth orbit. FALCON, built with Stanford spinoff EraDrive, uses each small satellite's existing star-tracking cameras to photograph nearby objects in space. The onboard computer then matches what it sees against a public catalog of roughly 20,000 tracked space objects, letting the satellite calculate its own exact position without any help from the ground. During a three-day test, FALCON's calculations for more than 200 space objects turned out to be more accurate than the predictions based on ground-based tracking data. NASA program manager Roger Hunter called it another success for the Starling mission, adding that it has far-reaching implications for tracking traffic in orbit, avoiding collisions, and navigating without GPS. Because GPS signals do not reach the moon or deep space, engineers say this kind of self-navigation could become essential for future lunar satellite swarms and human missions beyond Earth's orbit. Later this year, Starling will test whether its four satellites can refine their positions together as a team.

A slice of cheese might be doing more for your gut than you realize. Researchers in the Food Microbial Sciences Unit at the University of Reading tracked how three artisan cheeses made by Nettlebed Creamery in Oxfordshire changed as they aged. The team, led by PhD researcher Sabrina Longley along with Glenn Gibson and Anisha Wijeyesekera, studied a soft white-rind cheese aged about a week, a washed-rind semi-soft cheese aged several weeks, and a semi-hard cheese matured in hay for around nine months. As the cheeses aged, colonies of helpful bacteria transformed their flavor and texture while producing compounds that may benefit health. The washed-rind and hay-aged cheeses contained Propionibacterium freudenreichii, which produces propionic acid, a substance linked to reduced inflammation, appetite regulation, and lower cholesterol production. The white mould on the soft cheese, Penicillium candidum, produced chitin, a dietary fiber that can act as a prebiotic for gut bacteria. Longley said the ageing process creates complex aromas and textures through the work of an army of helpful bacteria. The researchers cautioned that more dietary trials in people are still needed before anyone can say for certain how eating these bacteria actually affects the gut and overall health.

Some new species take years of searching to find, but this one turned up on a single mountain slope in Thailand. A research team led by Poramad Trivalairat, from Chulabhorn Royal Academy and Kasetsart University, has described a new lizard species named Acanthosaura syrax. They found it in the evergreen forests of Mae Wong National Park, in western Thailand's Tak and Kamphaeng Phet provinces, at elevations above 1,300 meters, where it appears to live nowhere else. The lizard has yellowish-green coloring, a small body, and the smallest neck and back crest scales ever recorded in its genus. Unlike several close relatives, it has no black patch around its eye, but it does have a distinctive dark collar marking. Scientists chose the species name to match Syrax, the golden dragon ridden by Queen Rhaenyra Targaryen in the television series House of the Dragon, because both are small, yellow, and remarkably prolific. The discovery brings the number of known species in the genus Acanthosaura to 23. The study, which describes the lizard in full scientific detail, appears in the open-access journal ZooKeys.

A long Finnish study is challenging the common idea that screen time is simply bad for children's brains. Researchers at the University of Jyväskylä and the University of Eastern Finland followed 260 children, 124 girls and 136 boys, for eight years as part of the ongoing PANIC study. The team tracked each child's physical activity, sedentary behavior, and screen time from childhood, then tested their thinking skills at an average age of 15.8 using a computerized battery called CogState, which measures learning, attention, and working memory. Surprisingly, the children who had spent more time on screens over the years tended to show better cognitive processing as teenagers. The pattern differed slightly by sex: light daily activity was linked to stronger working memory in girls, while structured, guided activity mattered more for boys. Doctoral researcher Petri Jalanko cautioned that the results do not mean screen time is automatically good for young brains. He said the real goal is finding a balance between physical activity and screen time that encourages active thinking, since the study could not tell what the children were actually doing on their screens. Because the research only shows a correlation, the team said further studies are still needed before anyone gives firm advice about screen time.

Every proton in your body has stayed intact since almost the beginning of the universe, and scientists at Brookhaven National Laboratory think they now know part of the reason. Using the Relativistic Heavy Ion Collider, or RHIC, the STAR team smashed atomic nuclei together at nearly the speed of light and studied the particles that shot out. They found more three-quark particles, called baryons, flying out sideways than older models, which assume a proton's three quarks share its baryon number equally, could explain. By comparing baryon counts with electric-charge measurements from the same collisions, the researchers concluded that the missing baryon number was not carried by the quarks alone. Instead, it appeared to travel through a Y-shaped junction of gluons, the particles that bind quarks together, first predicted in the 1970s and proposed as a baryon-number carrier in 1996. Physicist Nicole Lewis of Rice University said a proton's lifetime is thought to be longer than the age of the universe itself, which lets atomic nuclei stay stable. Brookhaven's Rongrong Ma said the discovery reshapes how physicists think about the structure of matter. Because baryon number conservation is also tied to the mystery of why the universe has far more matter than antimatter, the finding, published in the journal Science, could offer new clues to one of physics' oldest puzzles.

On the evening of August 16, five giant bonfires blazed to life on the mountains surrounding Kyoto, marking one of Japan's most striking summer traditions. The event, called Gozan no Okuribi, is held every year to send the spirits of ancestors back to the afterlife at the close of the Obon holiday. Starting at 8 p.m., the giant character "Dai," meaning "great," was lit on Nyoigatake mountain in eastern Kyoto, followed five minutes apart by the characters "Myo" and "Ho," then the shapes of a boat, a smaller "Dai," and finally a Shinto gate called a torii. Each bonfire burned for about 30 minutes, its flames visible from riverbanks, parks, and rooftops across the city. No one knows for certain when the custom began, with some historians pointing to the Heian period roughly a thousand years ago and others to the Edo period a few centuries later. The tradition was suspended during the Second World War but was revived in 1946 and has continued every year since. Today, tens of thousands of residents and visitors gather along the Kamo River and other viewing spots to watch the fires in near silence.