Kyoto, Japan -- The two largest planets in our Solar System, Jupiter and Saturn, also have the largest satellite systems, or the most moons. At present, Jupiter's reported moon count stands at more than 100 moons, and along with its many rings Saturn has more than 280 reported moons. Not all these moons are equal, however. Jupiter's moon family has four large members, including the largest moon in the solar system, Ganymede, while Saturn's family is dominated by one large moon, Titan, the Solar System's second largest.

Since both planets are gas giants, the reasons for the differences in these satellite systems have long puzzled astronomers. Satellite formation theories have proposed some possibilities, but recent studies on stellar magnetic fields have hinted at the need to rethink these theories. There is also a long-running debate surrounding magnetic accretion and satellite formation: specifically, whether an inner cavity can be formed in Jupiter’s circumplanetary disk, the accumulation of material orbiting a planet from which satellites may form.

A physically consistent model that can explain multiple systems, like the satellite systems of Jupiter and Saturn, may be applicable to other planetary and satellite systems beyond the Solar System. This motivated a collaborative team of researchers from institutions in Japan and China, including Kyoto University, to develop such a model.

Astronomers using data from the Hobby–Eberly Telescope Dark Energy Experiment (HETDEX) have discovered tens of thousands of gigantic hydrogen gas halos, called “Lyman-alpha nebulae,” surrounding galaxies 10 billion to 12 billion years ago. Known as Cosmic Noon, this is an epoch in the early universe when galaxies were growing their fastest. To spur this growth, they would have needed access to vast reservoirs of hydrogen gas, a key building block for stars. However, until recently, astronomers had only found a handful of these essential structures. A new study published in The Astrophysical Journal has now increased the known number of hydrogen gas halos by a factor of ten: from roughly 3,000 to over 33,000. 

A new study published in Big Earth Data introduces the Cloud-Aware Mixture-of-Experts Linear Transformer U-Net (CA-MTransU-Net) for precise forest burned area (FBA) detection. By integrating Sentinel-1 SAR and Sentinel-2 optical data, the model overcomes traditional challenges such as cloud contamination and the high computational complexity of standard segmentation models. Achieving the highest mean Intersection-over-Union (mIoU) of 87.00% and an inference speed of 6.26 ms, this architecture significantly outperforms conventional benchmark models, offering a robust and efficient solution for post-fire environmental monitoring.

A class of undergraduate students at University of Chicago has used data from the Sloan Digital Sky Survey (SDSS) to discover one of the oldest stars in the universe, a star that formed in a companion galaxy and migrated to the Milky Way.

A new study published in Big Earth Data applies the INFORM Climate Change model to project future risks of humanitarian crises and disasters by integrating climate hazards, population dynamics, conflict, and socioeconomic development pathways. Incorporating forward-looking projections of vulnerability and coping capacity under different Shared Socioeconomic Pathways, the analysis shows that global risk may decline under moderate and rapid development scenarios but could rise sharply in the high-emission, fragmented SSP3 pathway. The findings provide evidence for prioritizing vulnerable regions and guiding targeted risk reduction and climate adaptation strategies.

New observations of "forbidden" planet TOI5205-b reveal surprising details about it its atmospheric chemistry.