NASA's well-traveled Voyager 1 is headed out of the heliosphere, the fluctuating bubble in space inflated by plasma streaming outward from the sun. For years Voyager 1 has been closing in on the heliopause—the outer edge of the heliosphere—where the solar wind meets the interstellar medium. Yet despite intriguing hints, the probe remains within the heliosphere, mission scientists announced last December. It appears that Voyager 1 has discovered another wrinkle in the structure of our local space environment, a kind of magnetic highway linking the heliosphere to what lies beyond.

“We're still inside, apparently,” said Voyager project scientist Edward Stone of the California Institute of Technology in a teleconference with reporters on December 3. “But the magnetic field now is connected to the outside. So it's like a highway letting particles in and out.”

Voyager 1 crossed into the new region in August, when it registered a huge drop in the number of low-speed solar particles in its environment and a corresponding jump in the number of higher-energy cosmic-ray particles arriving from outside the solar system.

Despite the influx of cosmic-ray particles, the team concluded that Voyager 1 is still inside the heliosphere because the probe's magnetometer has not yet registered a change in magnetic field direction, as would be expected when crossing the boundary from the sun's plasma to the interstellar medium. “If we had only looked at particle data alone, we would have said, ‘Well, we are out. Good-bye to the solar system,’” says Stamatios M. “Tom” Krimigis of the Johns Hopkins University Applied Physics Laboratory. “But nature is very imaginative, and Lucy pulled up the football again.”

Launched in 1977, Voyager 1 is now more than 18 billion kilometers from the sun, farther out than any man-made object has ever traveled. It takes radio signals 34 hours to make the round-trip from Earth to Voyager and back again. Still, no one knows how much farther Voyager 1 may travel before it breaches the heliopause. “It may take several more months—it may take several more years,” Stone says.

Adapted from Observations at blogs.ScientificAmerican.com/observations

This article was originally published with the title Not Quite Gone.

3 Comments

1. 1. David Russell 01:28 PM 1/20/13

   Someone recently said that the voyager must have left the gravitational hold of the sun. Does the word poppycock come to mind. In 1950, Dutch astronomer Jan Oort proposed that certain comets come from a vast, extremely distant, spherical shell of icy bodies surrounding the solar system.
   
   This giant swarm of objects is now named the Oort Cloud, occupying space at a distance between 5,000 and 100,000 astronomical units. (One astronomical unit, or AU, is the mean distance of Earth from the sun: about 150 million km or 93 million miles.) The outer extent of the Oort Cloud is believed to be in the region of space where the sun's gravitational influence is weaker than the influence of nearby stars.
   
   The Oort Cloud is said to be about 5,000 to 100,000 AU from the sun which at 93,000,000 miles time 100,000 puts it at 456,000,000,000 to 93,000,000,000,000 miles in radius. This is a conundrum in that the closest star would be Proxima Centauri (4.22 light years) Alpha Centauri is a star *system* made up of three stars. Of those three stars, Proxima Centauri is currently closest to us.
   
   At 4.22 light years and a light year being 5,869,713,600,000 miles in length. So extrapolate that to 4.22 X light year we get a mean distance of 24,770,191,392,000 miles away. So if the Oort cloud is at the outside range, then it encompasses the next nearest system, or it is just a bit more than 10% of a light year in diameter at the lower range.
   
   So what gives, is it gravity or electrical/magnetic fields keeping it in place? What I get out of this is we really don't have a clue yet. Maybe my math is off, but something doesn't smell right if the Oort cloud is attached to Sol, if it is an interstellar area that we share with other systems then this is new and seems the implications of what influences it even weirder.
   

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2. 2. m allworth 12:48 PM 1/25/13

   On Oct 15th 2009, NASA discovered a ribbon of electrically neutral atoms [ENAs] at the edge of the solar system.
   
   These 'neutral places' might be where some particles and maybe , even atoms that the solar system n
   'needs' are allowed to pass in or out?
   
   [ It appears there is an Oxygen : Neon discrepancy [111:74] between the interstellar medium and the solar system]NASA Feb 10th 2010.
   
   I wonder if this discrepancy may be due in part to the Heliosphere /and or/ ENAs ,filtering out or allowing in, some more of some atoms and / or/ 'outside particles' from outside of the solar system.
   
   
   The magnetic 'bubbles' discovered at the edge of the solar system may also have a filtering or other type of effect - an interesting idea?
   
   
   Also, from time to time, the magnetic field of our sun sends out connections to link up with the Earth's own magnetic field [NASA]. Is this some kind of magnetic adjustment or a sustaining interplay?
   
   Just how much of the suns influence/ or 'cell like' protection of the whole system do we know off?
   
   
   Best wishes,
   
   Marg.
   

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3. 3. David Russell in reply to m allworth 03:58 PM 2/26/13

   Sounds like you have studied Dyson's concept of GAIA. I like it because it takes what we call self and makes it nothing more than a self contained unit of a bigger unit. A very fractal solution to a very fractal problem.
   
   But what makes it interesting is that if what we identify as self is only a cog that perceives individuality in order to perform, we could learn to build some pretty neat thinking machines.

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