Voyager finds “froth” at the border of the solar system.

Like foam on a wave, I guess – or a kind of magnetic barrier. NASA says they’re surprised at what the space probes are turning up:

“The Voyager probes appear to have entered a strange realm of frothy magnetic bubbles,” says astronomer Merav Opher of Boston University. “This is very surprising.”

According to computer models, the bubbles are large, about 100 million miles wide, so it would take the speedy probes weeks to cross just one of them. Voyager 1 entered the “foam-zone” around 2007, and Voyager 2 followed about a year later. At first researchers didn’t understand what the Voyagers were sensing–but now they have a good idea.

“The sun’s magnetic field extends all the way to the edge of the solar system,” explains Opher. “Because the sun spins, its magnetic field becomes twisted and wrinkled, a bit like a ballerina’s skirt. Far, far away from the sun, where the Voyagers are now, the folds of the skirt bunch up.”

Astronomers think the magnetic bubbles might help protect us – that is, Earth, Neptune, all of us – from cosmic radiation.

Voyager 1 and 2, by the way, are the same ships with the Golden Records on them. It’s nice that they’re keeping in touch.

[via keepyourpebbles]