APOD 4.5

Pictured above is galaxy cluster ACT-CL J0102-4915 and is one of the largest objects known, spanning 7 million light years, dubbed El Gordo. The image is a composite image of dark matter (dark blue), visible light from an image from the Hubble telescope, and x-ray (pink) from the Chandra Observatory. Nearly all of the bright spots are different galaxies, which is in itself mind-blowing, let alone it's massive size. There are several interesting objects in the picture, such as two galaxies that are in the process of colliding.