Image: NASA (public domain).
What do a ballerina’s skirt and the sun‘s magnetic field have in common? In this ScienceCast, NASA tells us about a strange phenomenon that their space probes, Voyagers 1 2, discovered at the edge of our solar system — a froth of gigantic magnetic bubbles that separates us from the rest of the galaxy.
“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, these newly-discovered magnetic bubbles at the edge of the solar system are about 100 million miles wide — similar to the distance between Earth and the sun. It takes the Voyager probes several weeks to cross just one of them.
When Voyager 1 entered the “foam-zone” in 2007, followed a year later by Voyager 2, researchers didn’t understand what they were sensing at first. But now they think they’ve solved the puzzle.
“The sun’s magnetic field extends all the way to the edge of the solar system,” explains Dr 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.”