Physicists use high-energy accelerators to probe matter at the smallest scale.
More powerful than any microscope, a high-energy accelerator allows physicists to study the smallest things human beings have ever seen, for example the quarks inside a proton. At the same time, high-energy accelerators can recreate the conditions of the early universe though in a much smaller volume. Creating tiny fireballs of high density and high temperature, physicists produce the particles that were abundant in the early universe, a trillionth of a second after the Big Bang. Fermilab's Tevatron is the most powerful accelerator in the world. In 1995, the high-energy collisions of the Tevatron led to the discovery of the top quark, the heaviest elementary particle known to exist.