Saturn's Thunderstorms Reveal Invisible Particles express
A thundercloud stores electricity like a battery before a flash. It can discharge in two ways: by lightning or by producing particles with a tiny charge: these are called millicharged particles. Such particles are nearly invisible to detectors, but their trace can be caught by how often lightning strikes.
The authors compared thunderstorms on different planets in the Solar System. It turned out that thunderstorms in Saturn's atmosphere provide the best constraints on millicharged particles. If the clouds there are layered, then the charge of such particles must be greater than one ten-septillionth of the electron's charge. These are the strongest constraints for bosonic particles to date.
The idea is simple: if millicharged particles are produced in a thunderstorm, they carry away energy, and there are fewer lightning bolts. By comparing how many lightning bolts we see with how many we expect, we can figure out which particles might have stolen the energy. Thus, an ordinary thunderstorm becomes a laboratory for searching for new physics.
Original abstract
as written by the authors arXiv:2603.05338
We investigate the production of millicharged particles (mCPs) by the Schwinger mechanism in thunderstorms in the atmospheres of different planets in the Solar system. We consider a thundercloud as a giant capacitor that can be discharged in two ways: either by lightnings or by mCP production. Taking into account the observation of lightning strikes, we establish the constraints on the charge and mass of mCPs. We examine two types of cloud configurations: a simple arrangement of two clouds, and a more complex layered structure that gives rise to potential wells. In the latter case, we take into account the effects of Bose enhancement for scalar mCPs, and Pauli blocking for fermionic ones. We use the observational data of planetary atmospheres obtained by satellite missions to establish constraints on the charge and mass of mCP particles. The best constraints came from the observation of thunderstorms in Saturn's atmosphere under an assumption of layered cloud structure: $$q > 10^{-24}$$ for bosonic mCPs. These constraints for bosons are, to the best of our knowledge, the best in the literature.
A charge of $10^{-24}$ of the electron's charge is so small that at a distance of one meter, such a particle would be attracted to an ordinary electron with a force a billion times weaker than the attraction between two electrons.
In the series "Dark Matter," particles with fractional charge are the key to understanding the hidden sector of the Universe.