NASA IBEX spacecraft shows where we sit in the galaxy
By Jeff Salton
October 16, 2009
Move over Google Maps, NASA's Interstellar Boundary Explorer (IBEX) spacecraft has given scientists the tools to construct the first comprehensive sky map of our solar system and where it resides in the Milky Way galaxy. NASA says the new view will change the way researchers study the interaction between our galaxy and sun.
Six months in the making, the sky map was produced with data collected by two detectors on the IBEX. The detectors measured and counted particles that scientists call energetic neutral atoms. These atoms are created in the interstellar boundary region of the solar system. This region is where charged particles from the sun, called the solar wind, flow outward far beyond the orbits of the planets and collide with material between stars. The energetic neutral atoms travel in the opposite direction toward the sun from interstellar space at velocities ranging from an impressive 100,000mph to an amazing 2.4 million miles per hour. But this interstellar boundary emits no light that can be collected by conventional telescopes. Hence the mission to "see" what's there.
The new map shows the region that separates the nearest reaches of our galaxy, called the local interstellar medium, from our heliosphere - a protective bubble that shields and protects our solar system from most of the dangerous cosmic radiation traveling through space.
"For the first time, we're sticking our heads out of the sun's atmosphere and beginning to really understand our place in the galaxy," said David J. McComas, IBEX principal investigator and assistant vice president of the Space Science and Engineering Division at Southwest Research Institute in San Antonio. "The IBEX results are truly remarkable, with a narrow ribbon of bright details or emissions not resembling any of the current theoretical models of this region."
IBEX's information was complemented and extended by data collected using an imaging instrument sensor on NASA's Cassini spacecraft. Cassini has been observing Saturn, its moons and rings since the spacecraft entered the planet's orbit in 2004.
Jigsaw puzzle pieces coming together
NASA says the IBEX sky maps have also helped put observations from its Voyager spacecraft into context, and picked up a lot of information the Voyagers have missed. Launched in 1977, the twin Voyager spacecraft traveled to the outer solar system to explore Jupiter, Saturn, Uranus and Neptune. In 2007, Voyager 2 followed Voyager 1 into the interstellar boundary. The spacecraft are now in the midst of this region where the energetic neutral atoms originate. However, the IBEX results show a ribbon of bright emissions undetected by the two Voyagers.
"The Voyagers are ... missing the most exciting region," said Eric Christian, the IBEX deputy mission scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "It's like having two weather stations that miss the big storm that runs between them."
Mission accomplished, so far ...
The IBEX spacecraft was launched in October 2008 on a mission to discover the nature of the interactions between the solar wind and the interstellar medium at the edge of our solar system. The spacecraft is the latest in NASA's series of low-cost, rapidly-developed Small Explorers Program.