Neutron stars are the compressed cores of dead stars — city-sized objects with staggering density. Some of these stars become pulsars, cosmic lighthouses emitting strictly periodic radiation pulses. Their magnetic fields are billions of times stronger than Earth's; at the magnetic poles, they burst forth as turbulent fountains of plasma. It is in this extreme environment that, according to theoretical models, myriad axions are born — ghostly hypothetical particles that barely interact with ordinary matter and are considered one of the leading candidates for dark matter.

The axion field around the star can be imagined as an intangible fluid. When pulsar light punches through this "fluid," its electromagnetic oscillations experience a slight rotation — much like a boat subtly changes course in an underwater current. By measuring the angle of this rotation (an effect akin to birefringence), astrophysicists could uncover the properties of axions. However, near a neutron star, the familiar picture gets complicated: ultra-strong fields warp the fabric of spacetime itself, and standard calculations break down.

But the real surprise predicted by theorists is microscopic funnels. At the poles of a neutron star, turbulent plasma flows wash out axions, leaving behind tiny voids — regions of reduced field density. These voids collapse in billionths of a second, and this process generates a characteristic signal: a change in the pulsar's spin rate. Only ultra-precise atomic clocks, which track the slightest deviations in pulse period, can detect such minuscule fluctuations. So, to catch elusive dark matter, you don't necessarily need giant underground detectors, just observe the rhythm of voids at a neutron star, turning the cosmos itself into a natural laboratory.