For 15 years, the Fermi Space Telescope has kept watch over our Galaxy. And it spotted something unexpected: a crack in the Galaxy's floor. This crack lies near the Westerlund-1 cluster — a vast group of young, bright stars. These giant stars live violently: a powerful wind blows from their surfaces, and at the end of their lives, they explode as supernova. Together, they blow out gas and dust, forming a bubble. The pressure is so immense that it rips open a gap in the Galaxy's gas disk. Through this gap, like water through a crack in concrete, ultra-fast electrons and other charged particles burst outward. They were accelerated by a shock wave where the stellar wind slams into the surrounding material. The particles bounce between magnetic fields, and this process, discovered by Enrico Fermi, pumps more and more energy into them.

The particles themselves are invisible. But when such an electron, moving at tremendous speed, collides with a particle of light, a photon, it transfers its energy to the photon. The faint light turns into a powerful gamma-ray burst, which the Fermi telescope detects. This phenomenon is named after Arthur Compton. It turned out that in this escaping stream, the particles' energy is tens of times higher than in the ordinary interstellar medium. And the stream itself stretches for 150 light-years.

This is the first direct evidence of how massive star clusters (a key stage in stellar evolution) punch holes in the galactic disk. Through such cracks, cosmic rays, particles that influence the birth of new stars and the entire life of galaxies, leak into the halo. The crack does not heal; it becomes part of a vast ventilation system. Future telescopes will see this process in detail. For now, the floor beneath the Galaxy's feet is cracking.