High-energy collisions occur when particles, such as protons or electrons, collide at extremely high speeds, often close to the speed of light. These collisions are typically studied in particle accelerators like the Large Hadron Collider (LHC), where scientists can create conditions similar to those just after the Big Bang. During these collisions, the energy involved can produce new particles and reveal fundamental forces and interactions in the universe. By analyzing the results, researchers gain insights into the basic building blocks of matter and the laws governing their behavior, contributing to our understanding of particle physics.