NASA's Cassini spacecraft is helping to rewrite our understanding of the shape of our solar system as it moves through the local Milky Way galaxy.


In this illustration, the multicolored (blue and green) bubble represents the new measurements of the emission of particles known as energetic neutral atoms. Image credit: NASA/JPL/JHUAPL

Previous models pictured our solar system as having a comet-like appearance. The new results suggest a picture more like a bubble.
Cassini scientists created an image from this exotic region of space by detecting particles known as energetic neutral atoms.
It complements data collected by NASA's Interstellar Boundary Explorer.
When NASA's Cassini spacecraft began orbiting Saturn five years ago, a dozen highly-tuned science instruments set to work surveying, sniffing, analyzing and scrutinizing the Saturnian system.




"At first I was incredulous," said Tom Krimigis, principal investigator of the Magnetospheric Imaging Instrument (MIMI) at Johns Hopkins University's Applied Physics Laboratory in Laurel, Md. "The first thing I thought was, 'What's wrong with our data?'"

Krimigis and his colleagues on the instrument team published the Cassini findings in the Nov. 13 issue of the journal Science, which featured complementary results from NASA's Interstellar Boundary Explorer (IBEX). Together, the results create the first map of the heliosphere and its thick outer layer known as the heliosheath, where solar wind streaming out from the sun gets heated and slowed as it interacts with the interstellar medium.

The Cassini data also provide a much more direct indication of the thickness of the heliosheath, whereas scientists previously had to rely on calculations from models. The new results from Cassini show that the heliosheath is about 40 to 50 astronomical units (3.7 billion to 4.7 billion miles) thick and that NASA's twin Voyager spacecraft, which are traveling through the heliosheath now, will cross into true interstellar space well before the year 2020. Estimates as far out as 2030 had been suggested.

"These new data from Cassini really redefine our sense of our home in the galaxy, and we can now do better studies of whether our solar system resembles those elsewhere," Krimigis said.

http://www.jpl.nasa.gov/news/features.cfm?feature=2370

As soon Cassini crosses into true interstellar space, it will be destroyed and otherwise the data it will bring up than will be far more interesting than we gathered until now.

But the two Voyager are sure worth their money.

Interesting post , thanks for putting up this info nickelson which is now more than just conjecture, backed up by lots of expensive instrument data.

Cheers Nick appreciate your input as usual some interesting things to consider.