Zooming in on Ram Pressure Stripping in Galaxy NGC4921

This side-by-side composite shows ALMA (red/orange) data laid over Hubble Space Telescope (optical) images of NGC4921. A new study of the spiral bar galaxy revealed filament structures similar to the Pillars of Creation but significantly larger. These structures are caused by a process known as ram pressure stripping, which pushes gas out of galaxies, leaving them without the material needed to form new stars.