They look a little different using X-rays.
Scientists are able to pick up otherwise unseen details.
a team of astronomers has found that two galaxy groups are smashing into each other at a remarkable speed of about 4 million miles per hour. This could be the most violent collision yet seen between two galaxy groups.
The bigger picture with the two colliding groups:
Read more here:
https://www.nasa.gov/mission_pages/chandra/images/galaxy-gathering-brings-warmth.html