The solar wind is wind from the sun. It is a stream of charged protons, electrons and plasma shot out of the Sun. The wind is shot out at hypersonic speed, so fast that it can travel the whole length of the Solar System, nearly 1 light year and create the heliosphere. The particles are dangerous to astronauts and spacecraft. The Earth's magnetic field absorbs or soaks up a lot of the solar wind causing the aurora, the Northern lights and Southern lights.