Arsène Ferrière

Cosmic particles with energies millions of times greater than anything our accelerators can produce slam into the atmosphere and create a shower of secondary particles. This shower emits radio waves that antennas on the ground pick up. But the signal is weak: it's swamped by the radio noise of our galaxy and the receivers' own noise.

Cosmic rays are particles from deep space, accelerated to colossal energies. Smashing into the atmosphere, they trigger particle showers with radio waves. These waves are fingerprints, revealing the energy and direction of the intruder.