Planet Nine is a proposed, yet unobserved, distant planet invoked to explain the clustered orbits and similar tilts of a set of extreme trans-Neptunian objects (ETNOs) whose perihelia lie beyond 250 AU. Originating from work by Batygin and Brown in 2016 (building on earlier studies of objects like Sedna and 2012 VP113), the hypothesis models a super-Earth to mini-Neptune - originally estimated at 5-10 Earth masses - on a distant, eccentric orbit that shepherds ETNOs through long-term gravitational perturbations. Orbital estimates have evolved: initial semi-major axes of 400-800 AU have been revised in multiple studies (2021-2025) to values near a few hundred AU, with recent reported parameters around 290±30 AU, eccentricity ~0.29, an orbital period of several thousand years and an apparent magnitude near 21.
Evidence combines observed clustering, dynamical simulations, and explanations for high-inclination and perpendicular ETNO orbits, but alternative explanations and counterevidence remain. Critics attribute the clustering to observational bias and note newly discovered distant objects (e.g., 2017 OF201 and 2023 KQ14) whose orbits conflict with a simple Planet Nine model. Infrared and optical surveys (WISE, Pan-STARRS, NEOWISE) have not detected the object but also have not excluded a Neptune-sized body depending on its sky position; deep ongoing searches (including Subaru) continue. Proposed origins include an ejected giant-planet core, capture from another star, or primordial formation on a distant orbit; without a direct detection, the hypothesis remains conjectural.
Summary generated by AI from the linked article. hn.today is not affiliated with Hacker News or Y Combinator.
Asaf Karagila criticizes OpenAI's preprint on the Partition Principle, calling it muddled, poorly structured, and inadequately referenced. He emphasizes the need for careful evaluation of AI's role in mathematical research and the importance of rigorous standards. (karagila.org)
OpenAI reportedly discovered a proof for the famous unique games conjecture, a major problem in computational complexity. Researchers raced to publish their own results to stay ahead of the machines' advancements. (quantamagazine.org)
A $1.8 billion global initiative is expanding efforts to create AI-ready biological data for disease research. Major partners like Biohub, NIH, DOE, Google DeepMind, and Meta aim to develop predictive models to accelerate understanding and treatment of diseases. (biohub.org)
Research suggests that ADHD may be linked to disruptions in circadian rhythms, indicating a potential role for chronotherapy in treatment. This approach could improve symptom management by aligning therapy with the body's biological clock. (frontiersin.org)
Model collapse, where AI models lose rare and unconventional data, is not new and affects many areas beyond AI. It results in homogenized outputs that lack the diversity and mistakes crucial for progress and discovery. (rulr.dev)
Scientists using ESA's Mars Express have discovered that Mars's Arsia Mons Elongated Cloud forms through a rare process called homogeneous nucleation, which does not require dust or particles. This exotic physics challenges previous understanding of Martian cloud formation and has only now been modeled successfully with advanced simulations. (esa.int)
Today's best Hacker News stories, summarized and screenshotted, one email a day.