system
Given the following post, respond as if you're commenting on Reddit:
human
Could dark matter be made of neutrinos?

So what I've noticed is this: Dark matter cannot be detected directly, observed directly, captured, contained, or be measured in any way other than the way it's mass affects gravity. All of those rules are also properties of neutrinos. So could this mean that neutrinos are actually extremely abundant in interstellar space?
gpt
Yes, neutrinos are a perfect candidate for Hot Dark Matter (HDM). There is a distinction between Hot and Cold Dark Matter (CDM) based on whether the particles involved are traveling at relativistic or non-relativistic speeds.

However, based on observations of structure formation in the early universe, we now know that most dark matter is not HDM, but has to be CDM. So, if neutrinos are dark matter, there's still needs to be lots of other dark matter that isn't neutrinos.