Astronomers directly imaged two separate collisions between rocky objects in the Fomalhaut star system. Scientists previously thought the aftermath of one collision was a dust-covered exoplanet, reflecting starlight. Observable collisions provide unprecedented insights into the processes of planet formation.

In 2004, a bright point of light in the debris disk surrounding Fomalhaut was thought to be an exoplanet. But the spot disappeared. The 2023 appearance of a second bright spot in the disk led astronomers to reconsider. They now believe these are the first direct observations of collisions between planetesimals in a star system not our own. It cautions astronomers to not presume that faint points of light around a star are planets.

SAN ANTONIO — December 18, 2025 — The Southwest Research Institute-led Ultraviolet Spectrograph (UVS) aboard NASA’s Europa Clipper spacecraft has made valuable observations of the interstellar comet 3I/ATLAS, which in July became the third officially recognized interstellar object to cross into our solar system. UVS had a unique view of the object during a period when Mars- and Earth-based observations were impractical or impossible.

The paper “Resolved mass assembly and star formation in Milky Way Progenitors since z = 5 from JWST/CANUCS: From clumps and mergers to well-ordered disks” was published in the Astrophysical Journal. Led by Dr. Vivian Tan, who recently completed her Ph.D. at York University under the supervision of Prof. Adam Muzzin, provides the most detailed reconstruction yet of how the Milky Way may have evolved from its earliest phases to the structured spiral we see today. Tan and her colleagues examined 877 “Milky Way twins” — galaxies whose masses and properties closely match what astronomers expect the Milky Way would have looked like at different ages across cosmic time. By observing more distant, and therefore progressively younger examples of these galactic look-alikes, the team effectively charted a timeline of our galaxy’s life, with surprising results. Our Milky Way’s history started from a remarkably tumultuous youth before its more settled adulthood.

On 17 December, in the Atacama Desert in northern Chile, representatives from the Cherenkov Telescope Array Observatory (CTAO), the European Southern Observatory (ESO), and governmental authorities gathered to celebrate the official groundbreaking of the CTAO’s southern site, CTAO-South. After years of successful site preparations, the event marked the beginning of construction on the telescope foundations, paving the way for the first telescopes of the first and largest gamma-ray observatory in the southern hemisphere.

With the advancement of Internet applications, the global demand for broadband satellite communication services is incessantly escalating. Furthermore, there exists an exponential surge in the requisition for the capacity of satellite communication systems. In response to this evolving demand, the domain of satellite communication technology is progressively evolving toward the realm of high-throughput satellite (HTS) communication systems. The typical technical characteristics of HTS are: (a) the satellite adopts multibeam technology for beam overlapping coverage of the service area, which improves the quality of the wireless link while realizing the spatial dimension segmentation; (b) based on this, the system adopts multiple frequency multiplexing to improve the communication capacity of a single satellite; (c) the gateway station is tightly coupled with the user beam clusters are tightly coupled to complete 2-hop communication, which makes multiple gateway stations share the communication resources of the same satellite, forming a spatial isolation of the gateway stations, and once again realizing the frequency multiplexing of the gateway station links. A key requirement for future multibeam broadband satellite communication systems is the ability to flexibly adjust beam capacity according to changes in business distribution, in order to meet time-varying business requirements. Beam hopping technology provides an efficient solution to achieve the efficient use of frequency resources and power resources. At the same time, the use of beam hopping makes the beam hopping of satellite payload need to match the business signals of ground signal stations, bringing about the need for synchronization of beam hopping between satellite and ground.