Most shark fossils are just teeth—their cartilage skeletons usually decay long before they can fossilize. But in northwestern Arkansas, a series of geological sites known as the Fayetteville Shale has preserved dozens of rare, three-dimensional shark skeletons dating back more than 300 million years. In a new study published in Geobios, researchers reveal why: These fossils formed on a low-oxygen, highly acidic seafloor that preserved cartilage instead of destroying it.

Gas giants are large planets mostly composed of helium and/or hydrogen. Although these planets have dense cores, they don't have hard surfaces. Jupiter and Saturn are the gas giants in our solar system, but there are many other gas giant exoplanets in our galaxy and some are many times larger than Jupiter.

Using HARPS and HARPS-N spectrographs, astronomers have observed a nearby K-type star designated HD 176986, known to host two super-Earth exoplanets. The observations resulted in the discovery of another planet in the system at least several times more massive than Earth. The finding was detailed in a paper published January 28 in the Astronomy & Astrophysics journal.

Modern technologies increasingly rely on light sources that can be reconfigured on demand. Think of microlasers that can quickly switch between different operating states—much like a car shifting gears—so that an optical chip can route signals, perform computations, or adapt to changing conditions in real time. The microlaser switching is not a smooth, leisurely process, but can be sudden and fast. Generally, nearly identical "candidate" lasing states compete with each other in a microcavity, and the laser may abruptly jump from one state to another when external conditions are tuned.

Using an advanced machine-learning algorithm, researchers in the UK and Japan have identified several promising candidate locations for the long-lost landing site of the Soviet Luna 9 spacecraft. Publishing their results in npj Space Exploration, the team, led by Lewis Pinault at University College London, hope that their model's predictions could soon be tested using new observations from India's Chandrayaan-2 orbiter.

Pet owners want quick answers when their beloved cat or dog is sick. And if these furry friends are experiencing digestive distress, lethargy and fever, it's important to rapidly rule out serious illnesses like feline panleukopenia (also called feline parvovirus) and canine parvovirus. Now, researchers report improved lateral flow assays for at-home screening. In tests on veterinary clinic samples, the assays demonstrated 100% sensitivity and reproducibility for both parvoviruses.

Mathematics, like many other scientific endeavors, is increasingly using artificial intelligence. Of course, math is the backbone of AI, but mathematicians are also turning to these tools for tasks like literature searches and checking manuscripts for errors. But how well can AI perform when it comes to solving genuine, high-level research problems?

In order to build the computers and devices of tomorrow, we have to understand how they use energy today. That's harder than it sounds. Memory storage, information processing, and energy use in these technologies involve constant energy flow—systems never settle into thermodynamic balance. To complicate things further, one of the most precise ways to study these processes starts at the smallest scale: the quantum domain.

In nature, molecules often show a strong preference for partnering with other molecules that share the same chirality or handedness. A behavior that is quite evident in the phenomenon known as homochirality-driven entanglement, where molecules that are all left-handed or all right-handed preferentially recognize and wrap around one another, forming complex and interlocked structures.

A team of physicists from the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences, together with collaborators, has identified the dominant physical mechanism responsible for energy release in the nuclear isomer molybdenum-93m (Mo-93m). Using high-precision experiments, the researchers showed that inelastic nuclear scattering—rather than the long-hypothesized nuclear excitation by electron capture (NEEC)—is the primary driver of isomer depletion under their experimental conditions.