Voyager 1, the little spacecraft that could, is nearing the edge of the solar system and continuing to prove theorists wrong about solar wind — the massive outflow of particles produced by the sun.
The tiny spacecraft, launched 33 years ago, is now 10.8 billion miles from Earth and has reached the region of the solar system where the hot ionized gas, or plasma, emitted by the sun is ramming into the cold gas and dust of interstellar space and changing direction, curling around to envelope the solar system in a giant cloud called the heliosphere.
As a result, the solar wind is no longer going in the same direction as Voyager, but virtually perpendicular to it, and the spacecraft is actually measuring a small inward speed of the ionized gas, said Edward Stone of Caltech, the Voyager 1 project scientist.
Full story: Voyager 1: Cutting-edge science on solar wind from the brink of the solar system