Astronomers have been wrestling for years with the mystery of fast radio bursts — ultra-short yet incredibly powerful radio signals from distant galaxies. Some flash repeatedly, like beacons with an irregular rhythm, while others are detected only once, leaving behind nothing but questions. A recent hypothesis could unify both types: all these bursts are born on magnetars — the ultra-dense remnants of dead stars with colossal magnetic fields. But the key lies in their shape and motion. These magnetars are thought to be not perfect spheres but squashed, and they spin like a kicked top whose axis wobbles noticeably — a motion physicists call precession.

This precession makes the radio beam, which shoots out along magnetic field lines, sweep across space. When the beam points toward Earth, we see a bright flash; when it turns away, silence. So repeating bursts are naturally explained by the beam sweeping across the line of sight of terrestrial telescopes, while one-off bursts are chance hits when the wandering beam briefly crosses our planet. In other words, the source is the same, but its visibility to us depends on the complex geometry of its rotation.

The same non-sphericity has an interesting consequence for gravitational-wave astronomy. A spinning squashed magnetar should emit gravitational waves — ripples in the fabric of spacetime predicted by Einstein. However, precession smears the gravitational wave signal, robbing it of clarity, and current detectors, like those Rainer Weiss helped build, cannot yet pick it out from the noise. The irony is that the wobbly top masks the subtle gravitational ripple that might otherwise be "heard"—much like a shaking flashlight blurs its beam.

Incidentally, the magnetar's close cousin (the pulsar, a neutron star emitting strictly periodic radio pulses) was first discovered in 1967 by Jocelyn Bell Burnell. Back then, the rhythmic signals were so unusual that they were seriously taken for a message from an alien civilization. Today we know they are natural cosmic lighthouses, but their "erratic" magnetar siblings keep surprising us, hiding their secrets behind the dance of precessing beams.