The next time someone says you’re living in a bubble, remind them that we all are.

A pair of NASA space probes have detected an artificial bubble around Earth that forms when radio communications from the ground interact with high-energy radiation particles in space, the agency announced this week. The bubble forms a protective barrier around Earth, shielding the planet from potentially dangerous space weather, like solar flares and other ejections from the sun.

Earth already has its own protective bubble, a magnetosphere stretched by powerful solar winds. The artificial bubble that NASA found is an accident, an unintended result of the interplay between human technology and nature. When humans want to communicate with submarines near the surface of the ocean, they use a type of radio communication known as very low frequency waves, or VLF, transmitted from stations on the ground. Some of the waves can stretch all the way out into Earth’s atmosphere and beyond, where they affect the movement of the radiation particles bouncing around in the region. Sometimes, the interaction between VLF and these particles creates a barrier that can be seen by spacecraft orbiting the planet.

The bubble discovery comes from a robotic mission launched in 2012 to study the Van Allen radiation belts, two donut-shaped rings of charged particles that surround the Earth, held in place by the planet’s magnetic field. The results are described in a recent study in the journal Space Science Reviews.