2026-09-21の世界

Did you know a brand-new crater suddenly appeared on the Moon, and almost nobody noticed for nearly two years? Scientists named it McGetchin, after an early lunar scientist. It formed sometime between April 11 and May 22, 2024, when a comet or asteroid about the size of a three- to six-story building struck the Moon's surface. Robert Wagner, an image specialist working with NASA's Lunar Reconnaissance Orbiter, spotted the crater on October 24, 2025. He was doing a routine check, comparing hundreds of before-and-after pictures with special software. The software turns unchanged ground gray and highlights any bright or dark changes. McGetchin measures about 728 feet wide, roughly as long as two football fields, and 141 feet deep, deep enough to fit three school buses stacked on top of each other. Scientists say an impact this big happens on the Moon only about once every 100 years or more. Later, another instrument called Diviner found something else strange. The ground for four miles around the crater stays about 16 degrees Fahrenheit cooler at night than the surrounding surface. Researchers think loose, fluffy rock thrown up by the crash holds less heat than solid ground. This tiny, hidden crater is now teaching scientists new lessons about how the Moon keeps changing.

Could a real medieval castle be hiding inside a modern university building, without anyone noticing for 150 years? That is exactly what happened at University College Dublin, or UCD, in Ireland. Professor Tadhg O'Keeffe, a specialist in medieval architecture at UCD, studied a Victorian-era building on campus called Roebuck Castle. He discovered that the walls of a real Norman castle from the early 13th century are still preserved inside it, hidden just beneath the plaster. The original castle stood on an important road leading into medieval Dublin. People long believed it had been completely destroyed when the current building was built about 150 years ago. Instead, the Victorian builders simply built around the old stone walls, and even the courtyard behind the building still follows the shape of the medieval one. To prove his theory, O'Keeffe used watercolor paintings made by the artist Gabriel Beranger around 1765, which showed the castle's ruins in detail. Comparing those old paintings with the building's current walls confirmed the connection. Historical records even suggest King James II once stayed there, back in 1689. Thanks to this discovery, Roebuck Castle can now claim to be the oldest standing building on any university campus in Ireland. O'Keeffe published his findings in the magazine Archaeology Ireland in September 2026.

Have you ever seen a father and his son light an Olympic-style flame together? That is exactly what happened at the opening ceremony of the 20th Asian Games in Aichi-Nagoya, Japan, on September 19, 2026. Former Asian hammer throw champion Shigenobu Murofushi and his son Koji Murofushi, a former Olympic gold medalist in the same event, lit the cauldron together at Mizuho Athletic Stadium in Nagoya. The cauldron itself was shaped like a kinshachi, the golden tiger-fish ornament that famously decorates the roof of Nagoya Castle. The ceremony's theme was called 'Harmonic Heart Beat,' and it opened with the sound of a heartbeat. Violinist Taro Hakase performed an original song while 240 local citizen dancers moved together on the field. Heart-shaped drones filled the night sky above the stadium, glowing with lights and lasers. This is Japan's third time hosting the Asian Games, after Tokyo in 1958 and Hiroshima in 1994. About 17,000 athletes and officials from across Asia gathered for the event, competing in dozens of sports over sixteen days. For the first time, the Games did not use one traditional athletes' village, and instead housed competitors in hotels, a cruise ship, and container-style rooms. The Games will continue until early October, filling Aichi and Nagoya with sport and celebration.

Could a brand-new animal species look almost exactly like ones scientists already know? Yes, and researchers just proved it with a small frog from the Amazon rainforest. An international team led by biologist Celio Haddad of Sao Paulo State University in Brazil studied frogs in the flooded forests of western Acre, near the Moa and Croa rivers. At first glance, the frogs looked almost identical to other frogs in the genus Adenomera, which normally lives in dry forests, not flooded ones. To check if it was truly new, the team compared its DNA, body shape, and call with related frogs. They found something interesting: this frog lacks a dark spot on the underside of its forearm, unlike its close relatives. Its mating call is also different, a short sound with a slow, distinctive rhythm. The team named the new species Adenomera varcena, after varzea, the Portuguese word for Amazonian floodplain forest, its habitat. This is the first time any frog in this genus has been recorded living in a flooded forest instead of dry ground. The discovery shows that even well-studied animal groups can still hide new species in rich, remote habitats like the Amazon. Researchers say more expeditions to similar forests could reveal even more hidden species.