Neither "dark matter" nor "dark energy" can be made from atoms (i.e. from the periodic table), because atoms interact with photons. I think to say "it is someth

Neither "dark matter" nor "dark energy" can be made from atoms (i.e. from the periodic table), because atoms interact with photons. I think to say "it is something" is a strong claim, requiring strong evidence. Dark energy, in particular, can't be a kind of "stuff". We could "understand" something that doesn't interact with EM; but we'd have trouble observing it.