Solar Wind

The solar wind is a stream of particles that are emitted from the Sun into interplanetary space.

The effects of the solar wind can be seen when a comet that is passes near the Sun. The tail of the comet always points away from the Sun. This is because the material in the tail is driven out of the head of the comet by the solar wind.

The particles in the solar wind are positive ions and electrons. It is thought that the solar wind originates in lower density areas of the corona, called coronal holes.

The solar wind can have an effect on the Earth. Most of the solar wind particles directed at Earth never reach the surface of the Earth. The Earth’s magnetic field serves as an effective shield, since the charged particles cannot travel across the field lines. Some of the particles, however, travel along the field lines and come closest to the Earth near the magnetic poles. These charged particles are responsible for the aurora displays. This explains why aurorae are seen primarily near the magnetic poles. When solar activity is increased, the aurorae become more widespread. The increased abundance of charged particles in the earth’s atmosphere also creates radio interference.