system
Given the following post, respond as if you're commenting on Reddit:
human
How hot is the interstellar and intragalactic space in dense galaxy clusters?

It seems to me that the space within these galaxy clusters would be that much higher because of the energies involved. Could life as we know it exist there?
gpt
You're asking, broadly, about all the baryonic matter (ie nuclei (mostly H and He) and electrons) in the universe which aren't in compact bodies like stars and planets and black holes.

The interstellar and intergalactic media have many components, depending on their origin. 

For example, between galaxy clusters is the warm-hot intergalactic medium (IGM). Here, the density is as low as one particle per cubic meter, but because there's just so much damn *space* out in space, it may contain half of the baryonic matter in the universe. This matter is at temperatures of about a million Kelvin, and is ionized, due to a number of processes such as shock heating and AGN feedback. 

Within galaxy clusters, there is the intra-cluster medium (ICM). It's basically the part of the IGM that's within clusters. It's not a trivial detail either, there's about 10x as much baryonic matter in this gas as there is in stars. The ICM is similarly hot, like a million Kelvin, and glows in the X-ray part of the spectrum, making galaxy clusters have a sort of diffuse glow when viewed at these wavelengths. It's heated due to shocks, relativistic plasma outflows from galactic nuclei and other transients. Even plasma outflows generated by supernova remnants which is ejected from galaxies are retained at this scale.

These media are active areas of research interest because they couple the observational structure and evolution of galaxies to the structure of the clusters they live in. It's something we can study with simulations and with observations, allowing cosmologists to construct detailed models for how the contents of the universe evolve (and why things are they way that they are).