Grigory I. Rubtsov

Gamma-ray burst GRB 221009A flared so brightly that it was dubbed the 'brightest of all time.' The LHAASO observatory detected gamma rays from it with energies up to 13 TeV — thousands of times more energetic than particles in an X-ray machine.

A proton or an atomic nucleus slams into Earth's atmosphere at tremendous speed, and a cascade of billions of particles is born. This extensive air shower races toward the surface, while sensitive telescopes catch its faint glow. From the shape of the glow, physicists determine how deep the shower penetrated the atmosphere and what it was made of.