Stars and galaxies move as if held by an invisible scaffold. This hidden mass, dark matter, might consist of axions, predicted in 1977 by Helen Quinn and Frank Wilczek. Axions are almost imperceptible: they pierce through Earth without noticing atoms.

Physicists twisted a laser beam into a vortex — a bright ring with a dark center. At the heart of this whirlpool, they measured the amount of light particles (photons) using light tracking and ultra-precise wave measurements. Nearly 5% of the light disappeared, as if someone flipped a switch, only to return an instant later. The only explanation: photons temporarily turned into axions, as allowed by the standard theory of particles.

The experiment doesn't require giant magnets — a tabletop laser was enough. It points to a solution for the dark matter puzzle and hints at where asymmetry in nuclear forces comes from. The biggest surprise: axions are trillions of times lighter than an electron, yet they carried away 5% of the beam's energy, like a weightless pinch of salt siphoning a fifth of a cup of tea.