| Heliopause, boundary of the heliosphere, the spherical region around the Sun that is filled with solar magnetic fields and the outward-moving solar wind consisting of protons and electrons. |
| Voyager 1 made headlines around the world last year when mission scientists announced that the probe had apparently left the heliosphere. |
| The study of cosmic rays has taught us about the heliosphere, as well as the sun's affect on the earth's environment. |
| The International Heliophysical Year will continue the legacy of these previous events, extending global synoptic study to the heliosphere. |
| The two Voyagers are located in the outermost layer of the heliosphere, where the solar wind is slowed by the pressure of interstellar gas. |
| In such a perturbed Heliosphere both solar and galactic cosmic rays have quite different conditions of propagation than in the quiet heliosphere. |
