From: NASA HQ
Posted: Thursday, September 30, 2010
WASHINGTON -- New data from NASA's Interstellar Boundary Explorer, or IBEX, spacecraft, reveal that conditions at the edge of our solar system may be much more dynamic than previously thought. Future exploration missions will benefit in design and mission objectives from a better understanding of the changing conditions in this outer region of our solar system.
The IBEX has produced a new set of "all-sky" maps of our solar system's interaction with the galaxy, allowing researchers to continue viewing and studying the interaction between our galaxy and sun. The new maps reveal changing conditions in 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.
In October 2009, scientists announced that the first map data produced by IBEX revealed an unpredicted bright ribbon of energetic neutral atoms emanating toward the sun from the edge of the solar system. This discovery was unexpected to scientists, because the ribbon of bright emissions did not resemble any previous theoretical models of the region.
The IBEX spacecraft creates sky maps by measuring and counting particles referred to as energetic neutral atoms that are created in an area of our solar system known as the interstellar boundary region. This imaging technique is required since this region emits no light that can be collected by conventional telescopes. This interstellar boundary 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. These collisions cause energetic neutral atoms to travel inward toward the sun from interstellar space at velocities ranging from 100,000 mph to more than 2.4 million mph.
This second set of all-sky maps, created using data collected during six months of observations, show the evolution of the interstellar boundary region. The maps help delineate the interstellar boundary region, the area at the edge of our solar system that shields it from most of the dangerous galactic cosmic radiation that would otherwise enter from interstellar space. The new findings were published this week in the Journal of Geophysical Research - Space Physics, a publication of the American Geophysical Union.
"Our discovery of changes over six months in the IBEX ribbon and other neutral atoms propagating in from the edge of our solar system show that the interaction of our sun and the galaxy is amazingly dynamic," 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. "These variations are taking place on remarkably short timescales."
The IBEX spacecraft was launched in October 2008. Its science objective was to discover the nature of the interactions between the solar wind and the interstellar medium at the edge of our solar system.
"This situational awareness provided by IBEX shows our place in space is not constant," said Dick Fisher, director of the Heliophysics Division in NASA's Science Mission Directorate at the agency's Headquarters in Washington. "Better understanding of the dynamic environment of space is vital for successful planning for future exploration." The goal of the Heliophysics Division is to understand the sun and its interactions with Earth and the solar system.
The Southwest Research Institute developed and leads the IBEX mission with a team of national and international partners. The spacecraft is one of NASA's series of low-cost, rapidly developed missions in the Small Explorers Program. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the program for the agency's Science Mission Directorate.
For more information about IBEX, visit: http://www.nasa.gov/ibex
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