"It should be noted that a full 90% of the non-dark-matter mass of the universe appears to be in the form of very thin X-ray-hot plasma clouds surrounding large galaxy clusters, unlikely to condense to the point of star formation via understood processes."

Wow. Non-dark matter is ~5%, so non-xray-hot-halo matter is 0.5% of the matter universe? That's all the rocks, all the stars, all the exotic objects we can count. Half a percent?