M. Böttcher

Radioactive tritium decays, emitting an electron. Its energy is almost always the same, but sometimes, just a little less. This shortfall could mean that alongside the ordinary neutrino, another, hidden particle was born. The Standard Model describes three types of neutrinos, but scientists suspect there is a fourth — the sterile one.

At the center of the Milky Way, where the supermassive black hole Sagittarius A* churns gas clouds like a millstone, astronomers have caught an irregular pulse. Gamma-ray emission, the most energetic light in the universe, arrives not as a smooth wave but with a break, as if the Galaxy's heart beats with arrhythmia.