Physicists are getting a handle on the structure of the Universe, how everything is made of something else. Molecules are made of atoms, atoms are made of protons, neutrons and electrons, etc. Even smaller than that are the quarks and the leptons, which seem to be the basic building blocks of all matter.
We know dark matter exists. We know this because without it and dark energy, our Universe would be missing 95.4% of its mass. What’s more, scientists would be hard pressed to explain what accounts for the gravitational effects they routinely see at work in the cosmos. For decades, scientists have sought to prove its existence […]