A giant wave of hot gas, spanning some 200,000 light-years, has been found in the nearby Perseus galaxy cluster by our Chandra X-ray Observatory.
May 07 | 2017
The wave is about twice the size of our own Milky Way galaxy and thought to have formed billions of years ago. Observations from Chandra, coupled with a computer simulation, shows the gravitational disturbance resulting from the distant flyby of a galaxy cluster about a tenth the mass of the Perseus cluster. The event causes cooler gas at the heart of the Perseus cluster to form a vast expanding spiral, which ultimately forms giant waves lasting hundreds of millions of years at its periphery. Merger events like this are thought to occur as often as every three to four billion years in clusters like Perseus. Credit: NASA's Goddard Space Flight Center Music: "The Undiscovered" from Killer Tracks
February 05 | 2018
Rhea is a heavily-cratered, airless world, while Titan’s nitrogen-rich atmosphere is even thicker than Earth’s. This natural color image was taken in visible light by the Cassini spacecraft on Nov. 19, 2009, at a distance of approximately 713,300 miles (1,148,000 kilometers) from Rhea. After a nearly 20-year mission that overflowed with discoveries, the Cassini spacecraft ended its mission on Sept. 15, 2017. Credit: NASA/JPL-Caltech/Space Science Institute