Glossary · Thiên văn học
Solar wind
A continuous outflow of charged particles from the Sun, mainly protons and electrons in the plasma state, carrying the Sun's magnetic field with it.
Different regions of the Sun produce solar wind of different speeds and densities. Coronal holes produce fast wind, ranging from 500 to 800 km/s; the Sun's poles have large, persistent coronal holes, so high latitudes are filled with fast wind. In the equatorial plane, where Earth and the other planets orbit, the most common state is slow wind of about 400 km/s. Because the Sun rotates every 27 days, the solar wind winds into a complex spiral of fast and slow, dense and sparse streams.
At Earth, the solar wind distorts the planet's magnetic field into a teardrop shape in space. When charged particles from the wind become trapped in the field, they collide with air molecules above the magnetic poles and make them glow — the aurorae.