Dark matter is an invisible ocean that, as shown by observations by Vera Rubin, keeps stars in galaxies from flying apart. Physicists suspect that if dark matter consists of ultralight particles, in the cosmic cold it turns into a frictionless fluid — a so-called condensate. The galaxy's rotation whirls this condensate into giant whirlpools: invisible vortices stretched across thousands of light-years. Unlike whirlpools in a teacup, these structures live for billions of years, outlasting the stars themselves. Computer modeling showed that in galaxies like the Milky Way, vortices do not arrange haphazardly but form a strict hexagonal lattice, reminiscent of a honeycomb. This order is a direct consequence of quantum nature: only a unified wave can organize into a perfect pattern.
This lattice can be detected through its gravitational effect on light. Passing through a vortex, a light ray bends slightly — the effect of gravitational lensing, predicted by Albert Einstein. If a galaxy's axis points toward Earth, the bent light from distant stars creates a regular pattern of bright spots in the sky. Seeing such a pattern would give astronomers direct evidence that dark matter is indeed in a quantum condensate state.
Vortices in superfluid helium can exist indefinitely; analogous dark matter vortices can persist for billions of years.