The Sun is the main exogenous influence in the Solar System. It has many effects on Earth. Radiation from the Sun is a main cause of the surface temperature of the Earth, and for the growth of plant life. We are partly shielded from the Sun's solar wind by the Earth's magnetic field. Storms of solar particles would otherwise strip away the ozone layer which protects us from ultraviolet radiation. Sometimes we see aurorae, which are lights that can be seen at night near the poles.