Stray radio waves may push part of the Van Allen radiation belts away from Earth, which is good news for our satellites; the high-energy particles trapped in the belts can destroy a spacecraft's electrical equipment.

JHUAPL/LASP

When the Navy wants to send a message to an underwater submarine, it sometimes uses very low frequency (VLF) radio waves. These long wavelengths, beamed from large towers on the ground, are unique in their ability to travel through salty water. But some end up in space instead. There, according to a new report, they may be forming a protective bubble around Earth's atmosphere.

The discovery comes from the Van Allen Probes-two spacecraft, launched in 2012, that patrol the radiation belts surrounding Earth. The Van Allen radiation belts are zones where charged particles streaming from the sun get stuck in Earth's magnetic field. These high energy protons and electrons can destroy a satellite's electronics, which is a constant concern because the belts don't always stay in one place.

"The conventional wisdom is that the inner edge of the outer belt kind of moves in and out as the atmosphere-especially ionosphere and plasmasphere-grows and shrinks," says Phil Erickson, a space plasma physicist at MIT. But observations from the Van Allen Probes showed that radio waves may also play a role in determining the location of the radiation belts.