How deep is the deepest ocean—and how precisely can we actually measure it? A Japanese research team has mapped the Challenger Deep in the Mariana Trench using the EM124 multibeam echosounder aboard the research vessel Hakuho-maru.

Scientists were stunned when they discovered a fossilized tooth from a capybara that lived in the Atacama Desert in northern Chile almost 9 million years ago.

Frequently located on hillsides and in canyons surrounded by wildlands, one of the most comprehensive studies to date shows rich neighborhoods are more likely to catch fire. However, they are also likely to recover faster than lower-income areas.

By evaluating the health of waterways across the US, researchers have identified about one-third of rivers and streams that, if conserved and restored, could sustain the nation’s freshwater biodiversity in the face of habitat degradation and climate change. Mark Anderson of the Nature Conservancy, US, led the new study, published September 16, 2026, in the open access journal PLOS One.

It’s no secret that plastic and other human trash are a problem for marine life, but our understanding has long focused on the ocean’s surface. Now, a more complete picture is coming into focus, revealing that even some of our planet’s greatest depths have become home to our debris. As described in a study published on September 16, 2026 in the open access journal PLOS One, an international team led by Dr. Daniel Lauretta of Argentina’s natural science museum surveyed the Mar Del Plata Submarine Canyon in the southwestern Atlantic, finding that our trash has accumulated in a part of the planet we typically consider pristine.

New evidence from fossils representing two groups of human ancestors—Australopithecus and early Homo—adds an important piece to the puzzle about when our ancestors transitioned from a life often spent in trees to a life spent almost exclusively on the ground. An international research team led by the Keck School of Medicine of USC analyzed fossil data from seven human ancestors ranging from about 1.5 million to 3.7 million years old. The researchers measured the strength of arm and thigh bones, which adapt to the forces placed on them during life, to learn about how human ancestors used their bodies and moved through their environments. Animals that spend more time moving in trees tend to have relatively strong arm bones, while humans who walk upright on the ground tend to have stronger thigh bones. The team found that Australopithecus, an early ancestor that lived roughly two to four million years ago, had a distinct approach that resembles both modern apes and humans. These individuals had strong arms, suggesting they spent substantial time in trees, while the strength of their leg bones showed a more human-like pattern, suggesting they walked like humans on the ground. The early Homo individuals, descendants of Australopithecus that lived about 1.8 to 2.3 million years ago, had relatively strong leg bones and weaker arm bones—a pattern more similar to modern humans. The findings suggest that the transition from Australopithecus to Homo included a major shift in how human ancestors moved and lived. The team proposes that that relative limb strength is a ‘threshold trait,” a difference that marks an important and fundamental shift in behavior between Australopithecus and Homo.

Scientists have discovered several 518-million-year-old fossils that reshape the origins of the group of animals that contains starfish, and found that they ate their food using tentacles, and not passively using their gills as previously thought.