L. Sveshnikova

High above Earth, a satellite flies, and inside it is an instrument the size of a small wardrobe. It catches particles that have been racing through the galaxy for billions of years and finally slam into the detector. Such particles are called cosmic rays, and they bring news of distant stellar explosions.

At night over the Siberian taiga, a faint blue light sometimes flickers. It's not the aurora borealis but a cosmic-ray shower: a single particle from deep space slams into the atmosphere and shatters into millions of secondary particles. They race toward the ground in a broad front, like a ripple from a stone dropped into water, and make the air glow.