Dark matter is the invisible scaffolding that keeps galaxies from falling apart. Back in the 1970s, Vera Rubin showed that without it, stars on the outskirts would fly away like a carousel without its bolts. Ever since, scientists have been hunting for the particles that make up dark matter.

A new study has re-examined the candidates — triplets of particles predicted by extensions of the Standard Model. Physicists put them through a rigorous selection: they checked whether these triplets push ordinary matter too hard and whether enough of them survived from the Big Bang era. Almost all failed the test.

Only one type survived — electrically neutral triplets. But even they are questionable. The biggest surprise: this sole candidate might reveal itself not through a direct collision, but by annihilating at the center of our Galaxy, producing an excess of gamma rays. Future telescopes will test this hypothesis by peering into the heart of the Milky Way.