Kelvin-Helmholtz instability

An image of the Perseus cluster obtained by Chandra, with X-ray information enhanced. The frame's breadth can fit ten Milky Way galaxies. The cold front is visible at the 7 o'clock position relative to the centre. Credit: NASA, CXC, GSFC, Stephen Walker, et al.

How the Forces That Create Beautiful Clouds on Earth Also Sculpt Galaxy-Wide Bays