Earth's sun does more than generate heat and light. The solar wind is a stream of electrically charged gas particles rushing out from the sun into space. The source is the sun's corona, an envelope of plasma so intensely hot that the sun's gravity can't hold onto it. A fast gust of solar wind can take two to four days to reach Earth.
The solar wind typically travels at 400 kilometers per second (250 miles a second), constantly bombarding Earth. Occasionally, a hole in the corona will shoot out a gust that moves closer to 800 kilometers per second (500 miles a second), possibly reaching Earth in as little as two days. The speed varies because gusts of high- and low-speed particles often interact. The speed of any given jet of solar wind depends on the composition and the interaction of the particles.