| A small NASA spacecraft embarks on a two-year mission on Oct 18th to give scientists their first view of the happenings at the edge of the solar system. NASA hopes its new Ibex probe will help explain why the sun's protective heliosphere is shrinking. The Ibex probe, short for Interstellar Boundary Explorer, will study a chaotic region in space where the solar wind from the sun clashes with cold gases from interstellar space. The solar wind, a stream of charged particles spewing from the sun at 1 million miles (1.6 million kilometers) per hour, carves out a protective bubble around the solar system. This bubble known as the heliosphere shields against most dangerous cosmic radiation that would otherwise interfere with human spaceflight. |