Nature: In 2012, Stefan Gillessen of the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, and his colleagues spotted a gas cloud approaching Sagittarius A*, the black hole at the center of the Milky Way. It appeared that part of the cloud would get pulled off and hit the accretion disk that swirls around the black hole. The resulting collision would have created a large explosion of radiation. But that didn’t happen. As Gillessen’s team continued observing, they also looked at older data and found a second cloud of gas following the same path. They believe that means that the two clouds are actually part of a larger stream of gas, possibly pulled from a star that passed near Sagittarius A* within the last 100 to 200 years. Another group of researchers suggests that a star is hidden within the gas cloud and that the star’s gravitation is what kept the cloud from fragmenting and falling into the black hole.
The finding that the Saturnian moon may host layers of icy slush instead of a global ocean could change how planetary scientists think about other icy moons as well.
Modeling the shapes of tree branches, neurons, and blood vessels is a thorny problem, but researchers have just discovered that much of the math has already been done.
January 29, 2026 12:52 PM
Get PT in your inbox
PT The Week in Physics
A collection of PT's content from the previous week delivered every Monday.
One email per week
PT New Issue Alert
Be notified about the new issue with links to highlights and the full TOC.
One email per month
PT Webinars & White Papers
The latest webinars, white papers and other informational resources.