Having already revolutionized our understanding of the dwarf planet Pluto, NASA's New Horizons spacecraft is providing a rare look at the vast, seldom-visited region of space that is the outer solar system. New Horizons is currently cruising through deep space roughly 35 astronomical units out from the Sun. Prior to the spacecraft's July 14, 2015 encounter with Pluto, the spacecraft captured roughly three years worth of observational data detailing the characteristics of the all pervading solar winds known to emanate from our Sun.
The data was recordedby New Horizons' Solar Wind Around Pluto (SWAP) instrument, whichremained active as the rest of the probe's instruments hibernated inpreparation for the spacecraft's primary mission.
In 2012, as NewHorizons passed beyond the orbit of Uranus, the instrument began itsvigil, observing the behavior of the solar particles that make upthe solar wind as they made a 3 billion-mile pilgrimage to the orbitof Pluto.
The solar windsobserved in the inner solar system exhibit relatively clear patterns.Larger well-defined formations in the winds are often created bycoronal mass ejections, and the merging of faster and slowerwinds into larger "shocks." Subtler patterns arealso evident, created by the spin of our Sun, and the varyingstrengths of solar winds emanating from different regions of thestar's surface.
The data collected by the SWAP instrument is proving to be instrumental for filling in a blind spot in the observation of solar winds, and is pointing towards abreakdown in these intricate patterns as the solar winds travel intothe outer solar system.
Whilst stilldetectable, the subtle patterns created by the spin of our Sun wererelatively feeble, with the more imposing shocks in the solar windobserved in the inner solar system were noted to unpredictably mergeinto even larger features, or flatten out completely.
Beyond providing a rareinflux of data regarding the unpredictable weakening of the Sun'sinfluence in the outer reaches of our solar system, New Horizonsdetailed observations are also shedding light on a class of ionparticles known as anomalous cosmic rays. It is believed thatthese energetic particles are created when interstellar particlesbecome ionized by the solar winds. They have been known to travelfour times the speed of the surrounding winds, and are thought to bean influential force in determining the boundary of the solar windsand interstellar space.
The weaker, finalstages of anomalous cosmic rays have been observed by the Voyagerspacecraft at the interstellar boundary, but closer to Earth the moreyouthful and energetic particles are believed to pose a radiationthreat to astronauts operating outside of our planet's protectiveatmosphere.
A better understandingof the movement and evolution of the particles could allow scientiststo develop protective measures to shield future spacecraft and evenastronauts on long-duration missions to destinations such as Mars.
Source: NASA