Microscopic lightning bolts in the air are sparked by invisible rays from deep space.
April 20, 2026
Original Paper
Discharge at the Microscale: Using Optical Tweezers to Observe Muon-Induced Discharges of a Levitated Microparticle in Air
arXiv · 2604.16040
The Takeaway
Small electrical discharges on tiny particles were long thought to be caused by standard gas breakdown rules. This experiment used optical tweezers to hold a single microparticle and watch it discharge in real-time. The results show that the sparks only happen when a high-energy muon from space passes through the air and leaves a trail of ions. These ions are then captured by the particle, triggering the tiny blast of electricity. This means the electronics in our smallest devices are constantly being affected by cosmic radiation in ways we did not realize. It changes how we think about protecting micro-technology from environmental interference.
From the abstract
Electrical discharge at the smallest possible length and charge scales is not well understood. Using optical tweezers, we investigate spontaneous discharges of a single micron-scale particle levitated in air. These ``microdischarges'' have a typical size of $\sim$40 $|e|$, but can be as small as a few $|e|$ and as large as several hundred. The absence of a well-defined trigger charge and the weak dependence on particle size suggest events are not classical gaseous breakdown. Instead, we show tha