Merav Opher And The Edge Of Space



The new view: Because of interactions with the interstellar magnetic field, the heliosphere is pushed in along its southern hemisphere and bulges out along its northern one. Distortions in the solar magnetic field become so extreme at the edge of the heliosphere that it breaks down into magnetic bubbles of plasma 100 million miles wide. Courtesy NASA

Txchnologist (h/t Ritholtz):

Opher’s more recent work has revealed what may be an even more complex level of structure in the outer heliosphere. The leading edge is called the heliosheath. It has usually been pictured as a relatively thin, smoothly flowing layer of energized plasma.
But an analysis of Voyager data by Opher and Maryland’s Drake in 2011 suggests that the heliosheath is actually a thick cluster of plasma “bubbles” 100 million miles across. The sun’s magnetic field becomes increasingly pleated and folded in the plasma of the outer heliosphere, Opher explains; in the heliosheath, pieces of the magnetic field may detach themselves and reconnect into the self-organized structures of the bubbles.
If Opher’s suggestion holds up to further observations, it could force astronomers to rethink some of their ideas about cosmic rays. “The heliosheath is a shield,” she explains: its plasma stops some highly energetic particles called cosmic rays from entering the solar system. If the heliosheath’s structure is inconsistent, then the shield has holes in it. It might be stopping fewer cosmic rays than has been assumed—or it might be stopping more, if the bubbles absorb the particles more efficiently. A change in either direction could affect astrophysical models about phenomena that produce cosmic rays and the levels of radiation bathing planets around other stars, for example.
Frustratingly, the magnetic signatures for the bubbles are so weak that they hover near the detection threshold of the Voyager magnetometers. The best way to verify the bubbles’ existence would be to launch a new probe to the outer heliosphere—one that might have the benefit of a faster propulsion system and instrumentation that isn’t 35 years out of date.
For that reason, Opher has tried as much as possible to rally support for just such a mission. To her, she says, it’s like the Voyagers are “screaming urgently, ‘Send a better instrument! There’s so much to learn!’”

Way beyond my pay grade, but pretty cool.