TheNASA Voyager probesThey have really managed to go where no one has been before. On a silent glide to the stars, nearly 15 billion kilometers from Earth, they are sending news from the unexplored reaches of the solar system.
Using a computer model based on data from theTravel, mission investigators have shown thatthe outer limits of the solar system (heliopause) are full of giant magnetic bubbles, about 160 million kilometers wide, so it would take weeks for the probes to cross one of them.
“The Sun’s magnetic field extends all the way to the edge of the solar system,” explains Opher. “As the sun rotates, its magnetic field twists and wrinkles, like a ballerina’s skirt. Far, far from the sun, where the Voyagers are now, the pleats in the skirt pile up,” she adds. When a magnetic field is severely bent as in this case, interesting things can happen. Thelines of magnetic force intersect, and “connect” -magnetic reconnection, the same energy process underlying solar flares-, and the “folds of the skirt” tend toreorganize, sometimes explosively, into foam of magnetic bubbles. “We weren’t expecting to find something like this on the edge of the solar system, but there it is,” says Jim Drake, co-author of the work published by the magazineAstrophysics. “Magnetic bubbles appear to be our first line of defense against cosmic rays,” adds Opher.
The heliosheath
Theories of the 1950s had envisioned a very different scenario, in which the distant magnetic field was supposed to curve around arcs and eventually retract to meet the sun. In reality, these bubbles appear to be autonomous and substantially disconnected from the vast solar magnetic field.
Thedistant solar magnetic field structure-with or without foam- is of acute scientific importance, sincedefines the way it interacts with the rest of the galaxy. The researchers call the region where theTravelare now, which acts as the border between the Solar System and the rest of the Milky Way, “theheliofunda“.
ProbesVoyager 1 and 2They were launched into space in 1977 and are now more than 14 billion kilometers from Earth, making them the most distant artificial instruments ever sent by man.Traveling 1entered the so-called “foam zone” around 2007, andTraveling 2it followed a year later.
