Short gamma-ray bursts are colossal explosions that release, in a fraction of a second, energy comparable to what our Sun will emit over billions of years. Traditionally, their source is thought to be a black hole with an accretion disk of superheated plasma, formed when two neutron stars, the ultra-dense remnants of massive stars, merge. However, a more exotic hypothesis exists: an ergostar — an object whose spin is so rapid that it twists the very fabric of spacetime, creating something like a cosmic whirlpool. This vortex could unleash a blinding jet — a narrow beam of radiation that we detect as a gamma-ray burst.

Recent research revives the concept of the ergostar, but with a key twist: if the neutron star is made not of ordinary neutrons but of so-called 'strange matter'—a sort of quark 'jelly' where u, d, and s quarks are mixed into a single whole — then the ergostar becomes stable. Unlike a black hole, where matter collapses into a singularity, a point of infinite density, here the material is held back from compression by centrifugal forces. Imagine a funnel in a sink: the water doesn't vanish instantly down the drain but forms a stable, swirling structure thanks to its motion. Similarly, an ergostar maintains its shape through its enormous rotational momentum. The rotational energy stored within it can reach tenths of a solar mass: this giant reservoir is more than enough to power a gamma-ray burst.

Previously, ergostars were dismissed by theorists as unstable configurations: it was thought they would quickly lose energy and collapse. However, strange matter changes the game, making such objects viable. Notably, ergostars could be hiding among pulsars — rapidly spinning neutron stars that emit regular pulses of radiation. Pulsars were discovered in 1967 by Jocelyn Bell Burnell, and their catalog has been growing ever since. Some known pulsars might actually be ergostars. To tell them apart, scientists are pinning their hopes on future gravitational wave detectors — ripples in spacetime predicted by Einstein. These instruments could pick up a characteristic 'sound'—a gravitational-wave signal: that would differ between an ergostar and an ordinary neutron star, much like different musical instruments produce different tones.