Near the Edge of the Solar System, Voyager 2 Finds Magnetic Fluff
After three-plus decades of exploring the gas giants, passing the orbit of Pluto, and reaching points beyond, Voyager 2 has found something interesting near the edge of the solar system: surprisingly magnetic fluff. Researchers document their findings in this week’s Nature.
Of course, this fluff isn’t made from the dust bunnies you find under your bed, the ‘Local Fluff’ (a nickname for the Local Interstellar Cloud) is a vast, wispy cloud of hot hydrogen and helium stretching 30 light-years across [Discovery News]. Astronomers already knew this fluff was out there near the boundary area between our solar system and interstellar space. What surprised them is that the fluff is much more magnetized than they’d expected.
Voyager 2 isn’t actually in the fluff yet, but it can measure the area’s magnetism by observing how its magnetic field deforms the shape of the heliosphere, that balloon of space created by the solar wind pushing outward from our sun. The magnetic field is not only stronger than anticipated—3.7 to 5.5 microgauss—it’s also tilted off the galactic plane of the Milky Way by about 30 degrees, NASA investigator Merav Opher says. “The tilted field probably is a result from turbulence in the interstellar medium outside our solar system or results from collisions of clouds in the solar system neighborhood,” Opher says [USA Today].
Magnetism could answer the question of why the “Local Fluff” continues to exist at all. Though it formed from supernova remnants 10 million years ago, exhaust from other supernovae should have destroyed it by now. It would be like expecting a wisp of cigarette smoke to retain its structure in the middle of a tornado; some kind of force would need to be surrounding (or intertwined through) the smoke helping it resist being dispersed. In the case of the wispy Local Fluff, a magnetic field may be helping [Discovery News].
Next stop for Voyager 2: interstellar space, beyond the influence of the solar wind. By NASA’s calculations, the two voyagers have until about 2025 to keep exploring before their instruments operate no longer.