An anonymous reader shares a Motherboard article: Humans have accidentally created a protective bubble around Earth by using very low frequency (VLF) radio transmissions to contact submarines in the ocean. It sounds nuts, but according to recent research published in Space Science Reviews, underwater communication through VLF channels has an outer space dimension. This video explainer, released by NASA on Wednesday, visualizes how radio waves wafting into space interact with the particles surrounding Earth, and influence their motion. Satellites in certain high-altitude orbits, such as NASA's particle-watching Van Allen Probes, have observed these VLF ripples creating an 'impenetrable boundary,' a phrase coined by study co-author Dan Baker, director of the University of Colorado's Laboratory for Atmospheric and Space Physics. This doesn't mean impenetrable to spacecraft or asteroids, per se, but rather to potentially harmful particle showers created by turbulent space weather.