The Earth is a huge magnet, and its magnetic influence extends far into space. In our everyday environment, magnetic forces are of no importance and a sensitive instrument, the compass needle, is needed to detect them. That is because we, the materials we encounter in everyday life, even the oxygen and nitrogen which we breathe, are all electrically neutral. The atoms of oxygen, for instance, contain electrons with negative electric charges and protons which are positive, but the two charges balance each other andthe electric and magnetic forces cancel. Magnetic forces have almost no effect on neutral atoms. However, 60 miles (100 km) or more above the surface of the Earth, the natural environment is quite different. The fringes of the atmosphere at these heights are strongly heated by the Sun's x-rays and ultra-violet light (and by other causes as well), causing negative electrons to be torn off atoms and leaving the remainder of the atoms as positively charged "ions". These electrified fragments react strongly to the magnetic forces and can be steered and trapped by them.
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In our everyday environment, magnetic forces are of no importance and a sensitive instrument, the compass needle, is needed to detect them. That is because we, the materials we encounter in everyday life, even the oxygen and nitrogen which we breathe, are all electrically neutral. The atoms of oxygen, for instance, contain electrons with negative electric charges and protons which are positive, but the two charges balance each other andthe electric and magnetic forces cancel. Magnetic forces have almost no effect on neutral atoms. However, 60 miles (100 km) or more above the surface of the Earth, the natural environment is quite different. The fringes of the atmosphere at these heights are strongly heated by the Sun's x-rays and ultra-violet light (and by other causes as well), causing negative electrons to be torn off atoms and leaving the remainder of the atoms as positively charged "ions". These electrified fragments react strongly to the magnetic forces and can be steered and trapped by them.