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.
An ultracold atomic gas can sync into a single quantum state. Researchers uncovered a speed limit for the process that has implications for quantum computing and the evolution of the early universe.