Simulated Ultra-Diffuse Galaxies (IMAGE) University of Copenhagen - Niels Bohr Institute Caption This is a visualization of the stellar distribution in simulated ultra-diffuse galaxies. The galaxies are just as faint as dwarf galaxies, but are distributed over an area just as large as the Milky Way. New research shows that if there are a lot of supernovae during the star formation process, it can result in the stars and the dark matter in the galaxy to be pushed outwards, causing the extent of the galaxy to expand. The fact that the galaxy is spread over a larger area means that it becomes more diffuse and hard to observe with telescopes. The picture shows two simulated Ultra-Diffuse galaxies, over imposed on a Hubble Space Telescope image of background galaxies. Credit (Credit: Arianna Di Cintio, Chris Brook, NIHAO simulations and HST) Usage Restrictions (Credit: Arianna Di Cintio, Chris Brook, NIHAO simulations and HST) License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.