Deep space probes find our solar system is protected by 'magnetic bubble wrap'



Two Nasa probes gliding towards the stars nine billion miles from Earth, have made a surprising discovery - our solar system is surrounded by magnetic bubble wrap.

Voyager's 1 and 2, which were launched 34 years ago, a re the furthest man-made objects from our planet.

They are currently traveling at 38,000mph through the 'Heliosheath' - the border crossing between our system and interstellar space.



The heliosheath: Scientists thought our system was surrounded by graceful curving magnetic field lines, but probe data suggests it is more like a froth

Both probes are continuously beaming back data from the unexplored reaches of our solar neighbourhood.

Now they have sent back information that has taken Nasa scientists by surprise - it is bubbly out there.

According to computer models, the bubbles are about 100 million miles wide, so it would take the 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,' said Nasa guest investigator Merav 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.'



When a magnetic field gets severely folded like this, interesting things can happen. Lines of magnetic force criss-cross, and 'reconnect'.

The crowded folds of the skirt reorganize themselves, sometimes explosively, into foamy magnetic bubbles.

The 1,592lb Voyager 1 was launched in September 1977. It carries a gold-plated audio-visual disc about Earth in case it is ever found by aliens

'We never expected to find such a foam at the edge of the solar system, but there it is!' said Jim Drake from the University of Maryland.



Theories dating back to the 1950s had predicted a very different scenario: The distant magnetic field of the sun was supposed to curve around in relatively graceful arcs, eventually folding back to rejoin the sun.



The actual bubbles appear to be self-contained and substantially disconnected from the broader solar magnetic field.



Dr Opher said: 'The magnetic bubbles appear to be our first line of defense against cosmic rays.

'We haven't figured out yet if this is a good thing or not.'

Planet tour: Voyager 1 took this false colour snap of Saturn as it passed way back in 1980

On one hand, the bubbles would seem to be a very porous shield, allowing many cosmic rays through the gaps.



On the other hand, cosmic rays could get trapped inside the bubbles, which would make the froth a very good shield.



Scientists can't explain why energetic particle sensor readings suggest that the Voyagers are occasionally dipping in and out of the foam.



Dr Drake said: 'We are still trying to wrap our minds around the implications of these findings.'

Dr Opher added: 'We'll probably discover which is correct as the Voyagers proceed deeper into the froth and learn more about its organization.