Solar Wind

The solar wind is a continuous stream of particles that flows outward from the Sun through the solar system. The particles escape from the Sun because its outer atmosphere is very hot, and the atoms there move too rapidly for the Sun's gravity to hold onto them. The solar wind, which is made mainly of ionized hydrogen (free protons and electrons), flows away from the Sun at a velocity of several hundred kilometers per second. The solar wind continues past the outermost planet, Pluto, to the point where it becomes indistinguishable from the interstellar gases; this marks the end of the Sun's domain and is called the heliopause. Little of the solar wind reaches Earth's atmosphere, because the charged particles are deflected by our planet's magnetic field.