The story of matter starts with atoms — tiny units once thought to be indivisible. Each atom has a dense nucleus in its center, made of protons and neutrons, surrounded by much lighter electrons that move in wide orbits. But protons and neutrons are not truly fundamental. They are made of even smaller particles called quarks, held together by a powerful interaction known as the strong force.

Alongside quarks are leptons, a family of particles that includes the electron and the nearly undetectable neutrino. These two families — quarks and leptons — make up everything we know. All matter, from stars to skin cells, is built from their combinations. The remaining pieces of the puzzle are the force-carrying particles, which act like messengers that transmit interactions between matter particles.

Physicists explore this subatomic world using particle accelerators, gigantic machines that speed up particles to almost the speed of light before smashing them together. When they collide, energy briefly transforms into new particles — a direct demonstration of Einstein’s E = mc^2. Studying these fragments allows scientists to trace what lies beneath everything, revealing that the universe is built from only a few basic ingredients, arranged in endlessly creative ways.