This composite image from the Hubble Space Telescope’s Advanced Camera for Surveys and its Wide Field Camera 3 shows a huge cluster of galaxies some six billion light years away known as PSZ23 G138.61-10.84. The image is from an observing programme called the Reionization Lensing Cluster Survey, or RELICS. The RELICS project has studied 41 galaxy clusters to help locate the brightest distant galaxies for follow-on observations by the James Webb Space Telescope, scheduled for launch in 2020.
As seen from Earth, galaxies can appear in any number of orientations, from face on, with spiral arms on glorious display, to edge on, with the arms hidden from view behind a flattened plane of stars and dust. While not as spectacular, perhaps, edge-on views provide key insights into galactic structure.