The star-and-tentacle Medusa galaxy hangs like ink in the dark in this image taken by the Hubble Space Telescope. As Medusa galaxies move through intergalactic space, they slowly scatter galaxy-following gas in branches illuminated by clusters of star formation. These blue branches can be seen drifting under the core of this galaxy, giving it a jellyfish-like appearance. Known as JO201, this particular jellyfish galaxy is located in the constellation Cetus, named after a sea monster from ancient Greek mythology. This sea monster themed constellation adds a nautical theme to this image.

The branches of jellyfish galaxies extend beyond the bright disk of the galactic core. This particular observation comes from a study of the sizes, masses, and ages of star-forming clusters in the branches of jellyfish galaxies. Astronomers hope this will provide a breakthrough in understanding the link between pressure relief, the process that creates branches of jellyfish galaxies, and star formation.

This galactic seascape was captured using the Wide Field Camera 3 (WFC3), a versatile instrument that captures images in the ultraviolet and visible wavelengths. WFC3 is home to some of Hubble’s most spectacular images, from views of Jupiter and Europa to revisiting the Pillars of Creation.

jellyfish galaxies A type of galaxy that has long “tentacles” or “tails” of gas, dust, and stars, giving them a jellyfish-like appearance that appears to be moving away from the main body of the galaxy. These tentacles form when a galaxy moves rapidly through the hot gas of a galaxy cluster, causing the gas to separate from the galaxy and form a tail. This process is called pressure stripping and can have a significant impact on the evolution of the galaxy.