The term 'dark matter' may sound mysterious and sinister. However, it has a role to play in keeping galaxies like ours together, and also, other types of galaxies elsewhere in the universe. Astronomers now think that dark matter is a necessary component of large bodies containing lots of stars. https://www.evolving-science.com/space/atypical-new-galaxy-type-exhibits-virtually-no-dark-matter-00639