The spiral galaxy in this NASA/ESA Hubble Space Telescope image is IC 3225. It looks strikingly like it was fired from a cannon, hurtling through space like a comet with a tail of gas pouring out of a disk behind it. The scene where the galaxy appears from Earth’s perspective is fascinating. Many appear to be hanging silently in empty space, as if suspended from a string, while others star in more dynamic situations.
Objects far from Earth can deceive appearances, as IC 3225 is one of more than 1,300 members of the Virgo cluster of galaxies, although it itself is about 100 million light-years away. The location of the galaxy suggests some of the causes of this active scene. The density of galaxies within the Virgo Cluster creates a rich field of hot gas called the “intracluster medium” between the clusters, while the extreme mass of this cluster allows for some very fast There are galaxies that revolve around the center in orbits. Penetrating through the thick intracluster material, especially near the center of a galaxy cluster, places enormous “collision pressure” on the moving galaxy, stripping the galaxy of gas as it moves.
As galaxies move through space, the gas and dust that make up the intracluster medium creates resistance to the galaxy’s movement and puts pressure on the galaxy. This pressure, called ram pressure, removes star-forming gas and dust from galaxies, potentially reducing or stopping the formation of new stars. Conversely, the ram’s pressure could also compress other parts of the galaxy, which could promote star formation. Although IC 3225 is currently not very close to the cluster’s center, astronomers suspect it has undergone ram pressure stripping in the past. The galaxy appears to be compressed on one side, with significantly more star formation at its leading edge (lower left), while the opposite edge is misshapen and elongated (upper right). Being in such a crowded region, a close call with another galaxy may have pulled IC 3225 into its shape. The sight of this distorted galaxy is a reminder of the incredible forces at work on an astronomical scale that can move and reshape entire galaxies.
