High-energy particles are subatomic particles that possess a significant amount of energy, often found in cosmic rays or produced in particle accelerators like the Large Hadron Collider. These particles can include protons, electrons, and heavier ions, and they play a crucial role in understanding fundamental physics and the universe's origins. When high-energy particles collide with matter, they can produce showers of secondary particles, leading to various phenomena observable in astrophysics. Studying these particles helps scientists explore extreme conditions in space, such as those near black holes or during supernova explosions, providing insights into the universe's most energetic events.