The universe is confusing me, and I am no expert on dark matter and dark
energy. I thought dark matter was "discovered" to explain the rotation of
galaxies. So isn't it just matter that is not warm enough (like humans) to
be seen with an optical telescope? But it still has gravitational effects
like ordinary matter. I'm reading online that dark matter is a different
kind of matter altogether, or is it just fundamental particles that can't
be touched like ordinary matter? Does anybody really understand this?