The new "foam zone" theory is based on a computer model created using data from NASA's twin Voyager spacecraft, both launched in 1977 and currently about 10 billion miles (16 billion kilometers) from Earth.

In 2007 Voyager 1 recorded dramatic dips and rises in the amount of electrons it encountered as the craft traveled through the heliosphere—the "force field" that surrounds the entire solar system and is created by the sun's magnetic field. Voyager 2 made similar observations of these charged particles in 2008.

A NASA computer model suggests the electron readings make sense if it's assumed the spacecraft were entering and exiting magnetic bubbles lining the edges of the heliosphere.

These magnetobubbles should act as electron traps, so the spacecraft would