The edge of the solar system is tied up with a ribbon, astronomers have discovered. The first global map of the solar system reveals that its edge is nothing like what had been predicted. Neutral atoms, which are the only way to image the fringes of the solar system, are densely packed into a narrow ribbon rather than evenly distributed.

"Our maps show structure and energy spectra that are completely different from what any model has predicted," says study coauthor Herbert Funsten of the Los Alamos National Laboratory in New Mexico.

NASA's Interstellar Boundary Explorer satellite, or IBEX, discovered the narrow ribbon, which completes nearly a full circle across the sky. The density of neutral atoms in the band is two to three times that in adjacent regions.

These and related findings, reported in six papers posted online October 15 in Science, will not only send theorists back to the drawing board, researchers say, but may ultimately provide new insight on the interaction between the heliosphere — the vast bubble in which the solar system resides — and surrounding space.

The bubble is inflated by solar wind, the high-speed stream of charged particles blowing out from the sun to the solar system's very edge. For 48 years, researchers have assumed that the solar wind sculpted the structure at the heliosphere's boundary with interstellar space, says Tom Krimigis of Johns Hopkins University's Applied Physics Laboratory in Laurel, Md.. But the newly found ribbon's orientation suggests that the galaxy's magnetic field, just outside the heliosphere, seems to be the chief organizer of structure in this region, says theorist Nathan Schwadron of Boston University, a lead author of one of the studies.

It's not known whether the ribbon lasts for just a few years or is a permanent feature.

http://www.sciencenews.org/view/generic/id/48456/title/Solar_systems_edge_surprises_astronomers