The Heliosphere is the vast, bubble-like region of space influenced by the Sun, created by the solar wind—a stream of charged particles emitted by the Sun. This region protects the solar system from galactic cosmic rays.
The name "Heliosphere" comes from "Helios," the Greek word for Sun, and "sphere," indicating its roughly spherical shape. It covers from the Sun out to the heliopause, about 123 AU away.
Significant events include the crossing of the termination shock by Voyager 1 in 2004 and Voyager 2 in 2007. Voyager 1 crossed the heliopause in 2012, entering interstellar space.
Ongoing studies by IBEX and other missions map the heliosphere's structure.
