Voyager 1 Returns Surprising Data about an Unexplored Region of Deep Space

[Buster's Uncle]

Voyager 1 Returns Surprising Data about an Unexplored Region of Deep Space
Scientific American
John Matson 2 hours ago 

About the Voyager 1 spacecraft, this much is clear: the NASA probe has traveled farther than any other. Voyager 1 is now more than 18.5 billion kilometers from the sun--almost 125 times the distance between Earth and the sun. The spacecraft, one of two Voyagers launched by NASA in 1977, is truly in unexplored territory--so much so that defining its current whereabouts poses a bit of a challenge.

Someday soon, it is expected, Voyager 1 will become the first spacecraft to exit the heliosphere--the bubble of solar plasma encasing the sun and planets--and enter the interstellar medium. Right now, however, Voyager appears to be crossing through one of  several puzzling new regions of the heliosphere that mission planners had not anticipated.

In a trio of studies published online June 27 in Science, Voyager scientists describe the latest heliospheric wrinkle discovered by the probe en route to interstellar space. Voyager 1, they report, appears to have crossed last August into what is now being called the "heliosheath depletion region."  The researchers described some characteristics of the new region in a December 2012 teleconference with reporters, but the new studies go into far more detail about Voyager 1's environs.

One major change signaling that Voyager had entered new territory was a sudden decrease in the number of particles from the sun hitting the spacecraft's Low Energy Charged Particle (LECP) instrument. On August 25, those solar particles dropped to less than one-thousandth their prior levels. Simultaneously, cosmic rays emanating from sources elsewhere in the galaxy began striking the LECP at a rate nearly 10 percent above the previous clip.

A second particle detector known as the Voyager Cosmic Ray Subsystem noted a similar change: charged atomic nuclei from the sun disappeared as nuclei from outside the solar system surged.

Such changes might seem a clear marker that Voyager 1 has completed its ultimate mission by breaking free of the sun's plasma cocoon and reporting back from the unexplored realm of interstellar space. But crucial measurements from a third Voyager instrument contradict that conclusion.

 The heliopause--the boundary between the local heliosphere and the interstellar medium beyond--is a boundary not only of particles but of magnetic fields as well. And although the magnetometer on Voyager 1 did register an increase in magnetic field strength as the spacecraft crossed over into the new realm, the direction of the magnetic field did not change. So either Voyager 1 has measured the interstellar magnetic field and found that it somehow perfectly aligns with the solar system (a possibility that the Voyager researchers consider "highly improbable") or, more likely, the spacecraft remains within the sun's magnetic domain.

Taken together, the evidence suggests that the heliosheath depletion region now being explored by Voyager is a new kind of solar system environment, one where the sun's influence wanes and interstellar particles can enter more easily. And although the new region appears not to qualify as interstellar, the researchers report, it "may form part of the interface between solar plasma and the galaxy."

So godspeed, Voyager. May you soon reach interstellar space--a place humankind has never before accessed. And may we know it when you see it.

http://news.yahoo.com/voyager-1-returns-surprising-data-unexplored-region-deep-181500828.html

---How many times does this make it that it's left the solar system in the last five years?   Don't bother to mention that, or ask the JPL guys about it or anything - it's not like you're posing as a science writer.

[Buster's Uncle]

NASA: Voyager 1 Is in a 'New Region' of Space
By Rebecca J. Rosen | The Atlantic – 1 hour 52 minutes ago...

For months, space enthusiasts have been sitting on the edges of their seats, ready for the Voyager 1 spacecraft to become the first emissary of human civilization to cross from the bubble around our sun* into interstellar space. Last August, two of the three instruments on Voyager 1 started sending back signals that something was -- suddenly, dramatically -- different. Particles from our sun fell way off, and cosmic rays from outside our system shot up. Was this the moment we'd all been waiting for?

Well, not quite yet. That third indicator -- the magnetic field data -- has turned out to be a bit, well, stubborn, showing month after month that Voyager is still in our sun's magnetic field. Two out of three ain't bad, as they say, but scientists need all three boxes checked before they will officially say that Voyager has crossed over, NASA explained in a release today.

Now scientists are giving Voyager's current home a new name -- the heliosheath depletion region. As Kelly Oakes writes in a terrific explanation in Scientific American:

Yep, what Voyager's instruments are now showing us is so odd we need a new name for it. Voyager is, almost literally, pushing the boundaries of our knowledge about the solar system.

Which, if you think about it, is hardly surprising. As Stamatios Krimigis of John Hopkins University, Maryland, and his colleagues write in one of the three papers out today, our ideas about the size and shape of the bubble of plasma we call the heliosphere, created by the solar wind that continuously flows from the sun, are older than the space age.

A trio of papers published in Science today details what scientists know about this new region, including two temporary shifts in the magnetic field data that occurred on May 29 and September 26 of last year, both times reverting to the data associated with our heliosphere (the bubble of solar winds emanating from our sun).

Voyager 1 launched in 1977 and has been traveling at astounding speeds for nearly 36 years (around 38,000 miles per hour currently). It is now more than 11 billion miles away from the sun. As we wait for it to reach its next and perhaps final frontier, scientists don't have a clear idea of what to expect. "I mean this is the first time any spacecraft has been there," Voyager project scientist Ed Stone of Caltech said to me last year.

We didn't know that the "heliosheath depletion region" was going to be there, or that it was going to be this big, but now that Voyager's been there for a while, we may as well give it a name. And while Voyager's departure from our heliosphere might not be the sort of clean, sudden that many of us would find satisfying, the new region is, well, a new region -- a piece of our little home in the universe that we didn't know about before, and now, thanks to Voyager, we do.



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*Clarification and correction: Technically, Voyager 1 is on the boundary between interstellar space and the heliosphere, not the solar system, because the solar system extends far beyond the heliosphere (the bubble of the solar winds) to include all objects influenced by the sun's gravity, which includes the Oort cloud, approximately a light year away -- much, much farther than Voyager 1 is now. An earlier version said "solar system" in spots where I was technically referring to the heliosphere. Thanks to Tom Standage for bringing this up on Twitter.

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