The solar wind consists of protons, electrons and other heavier irons and they have velocities of several hundred km per second. Moving charged particles experience a force when in an external magnetic field. The Earth's magnetic field at the equator has a value of approximately 3 x 10-5 T and is directed to the north. This field strength extends into the space above the earth.

Consider a solar wind proton moving at 5 x 105 m/s that approaches the earth from outer space along a line toward the center of the earth that lies on the plane of the equator. In what direction will the proton be deflected? Will it reach the earth's surface? What if the particle were an electron? Why is the Earth's Magnetic field important to life on the Earth?