Ultra-diffuse galaxies are a relatively new class of galaxies that were first discovered in 2015. They are as large as our Milky Way but have between 100 to 1,000 times fewer stars than our own Galaxy, making them barely visible and difficult to study. All previously studied ultra-diffuse galaxies have been in galaxy clusters, which informed the basis for the theory that they were once ‘normal’ galaxies, but with time have been blasted into a...
