WASHINGTON -- NASA's Interstellar Boundary Explorer, or IBEX,spacecraft has made it possible for scientists to construct the firstcomprehensive sky map of our solar system and its location in theMilky Way galaxy. The new view will change the way researchers viewand study the interaction between our galaxy and sun.
The sky map was produced with data that two detectors on thespacecraft collected during six months of observations. The detectorsmeasured and counted particles scientists refer to as energeticneutral atoms.
The energetic neutral atoms are created in an area of our solar systemknown as the interstellar boundary region. This region is wherecharged particles from the sun, called the solar wind, flow outwardfar beyond the orbits of the planets and collide with materialbetween stars. The energetic neutral atoms travel inward toward thesun from interstellar space at velocities ranging from 100,000 mph tomore than 2.4 million mph. This interstellar boundary emits no lightthat can be collected by conventional telescopes.
The new map reveals the region that separates the nearest reaches ofour galaxy, called the local interstellar medium, from ourheliosphere -- a protective bubble that shields and protects oursolar system from most of the dangerous cosmic radiation travelingthrough space.
"For the first time, we're sticking our heads out of the sun'satmosphere and beginning to really understand our place in thegalaxy," said David J. McComas, IBEX principal investigator andassistant vice president of the Space Science and EngineeringDivision at Southwest Research Institute in San Antonio. "The IBEXresults are truly remarkable, with a narrow ribbon of bright detailsor emissions not resembling any of the current theoretical models ofthis region."
This graphic llustrates one of the possibilities for the bright ribbon of emission seen in the IBEX ENA maps. The galactic magnetic field shapes the heliosphere as it drapes over it. The ribbon appears to trace the area where the magnetic field is most parallel to the surface of the heliosphere (the heliopause).
(Photo Credit: SwRI)
NASA released the sky map image Oct. 15 in conjunction withpublication of the findings in the journal Science. The IBEX datawere complemented and extended by information collected using animaging instrument sensor on NASA's Cassini spacecraft. Cassini hasbeen observing Saturn, its moons and rings since the spacecraftentered the planet's orbit in 2004.
The IBEX sky maps also put observations from NASA's Voyager spacecraftinto context. The twin Voyager spacecraft, launched in 1977, traveledto the outer solar system to explore Jupiter, Saturn, Uranus andNeptune. In 2007, Voyager 2 followed Voyager 1 into the interstellarboundary. Both spacecraft are now in the midst of this region wherethe energetic neutral atoms originate. However, the IBEX results showa ribbon of bright emissions undetected by the two Voyagers.
"The Voyagers are providing ground truth, but they're missing the mostexciting region," said Eric Christian, the IBEX deputy missionscientist at NASA's Goddard Space Flight Center in Greenbelt, Md."It's like having two weather stations that miss the big storm thatruns between them."
The IBEX spacecraft was launched in October 2008. Its scienceobjective was to discover the nature of the interactions between thesolar wind and the interstellar medium at the edge of our solarsystem. The Southwest Research Institute developed and leads themission with a team of national and international partners. Thespacecraft is the latest in NASA's series of low-cost, rapidlydeveloped Small Explorers Program. NASA's Goddard Space Flight Centermanages the program for the agency's Science Mission Directorate atNASA Headquarters in Washington.
Source: NASA/Goddard Space Flight Center