The galactic jellyfish prominently featured in this image from the NASA/ESA Hubble Space Telescope is actually the JW100 galaxy (bottom right). Streams of star-forming gas dripping like streaks of fresh paint from the galaxy's disk are created by a process called ram pressure stripping. Their resemblance to the dangling tentacles has led astronomers to refer to JW100 as a "jellyfish" galaxy. JW100 is located 800 million light-years away in the constellation Pegasus.

Ram pressure stripping occurs when galaxies encounter diffuse gas that covers galaxy clusters. As galaxies pass through this weak gas, it acts like a counterwind, stripping away gas and dust from the galaxy, creating trailing streamers that prominently adorn the JW100. Bright elliptical patches in the image are other galaxies in the cluster hosting JW100.

Toward the top of this image are two bright spots surrounded by a rather bright field of diffused light. This is the core of IC 5338, the brightest galaxy in the galaxy cluster. IC 5338 is an elliptical galaxy with a large halo, a type of galaxy called the cD galaxy. These galaxies probably grow by consuming smaller galaxies, so it's not unusual for them to have more than one nucleus, as their nuclei can take a long time to absorb. The bright spots of light adorning the galaxy's outer fringes are a rich population of globular star clusters.

This observation took advantage of Hubble's Wide Field Camera 3 and its features. The data are part of a series of observations designed to investigate star formation in the branches of jellyfish galaxies. These branches represent star formation under extreme conditions and could help astronomers better understand the process of star formation elsewhere in the universe.