You might think you learned in high school that the universe is made of atoms and molecules, protons and electrons, stars and galaxies, but over the last few decades astronomers have concluded — not happily — that all this is just a scrim overlying a much vaster shadowy realm of invisible “dark matter” whose gravity determines the architecture of the cosmos.

In related news, there is a new Nature article about "The moment of truth for WIMP Dark Matter"