Besides galaxies and dark matter, what is a defining hot component filling Galaxy Clusters?
Answer
Superheated gas reaching millions of degrees
Galaxy clusters are massive structures that contain not only galaxies and dark matter but also superheated gas often reaching temperatures of tens of millions of degrees.

#Videos
Astronomers Spotted the Biggest Thing Ever Discovered in Space
Related Questions
What is the typical upper limit on the number of galaxies found in a Galaxy Group?Besides galaxies and dark matter, what is a defining hot component filling Galaxy Clusters?How is the Local Group situated relative to the Laniakea Supercluster?What is the approximate density of matter in the Intergalactic Medium?In the Cosmic Web analogy, what feature represents the immense regions nearly empty of galaxies?What major cosmological concept does the Sloan Great Wall's size challenge?How was the most recently identified contender, Quipu, primarily traced?What is the estimated scale of the Hercules–Corona Borealis Great Wall (H-CB GW)?Which structure is described as stretching 1.3 billion light-years and resembles knotted strings?If structure is strictly defined as a single, continuous object without significant empty space, what would be the largest candidates?