Current Affairs

Among the first to get to grips with electricity and magnetism was a handsome young self-taught fellow, with great lips. Featured on the new £20 notes, Michael Faraday (1791-1867) learned his trade on the hoof, beginning as an assistant at the Royal Institution. Faraday's investigations proved that electricity and magnetism are but two aspects of one force. He experimented by thrusting a magnet into a coil of wire discovering that an electric current is produced.

Faraday's work laid the foundation for a major unification of the fundamental forces in physics. He also tried hard to prove a link between gravity and electricity. Although unsuccessful, he never relinquished the thought that it could be done. Why did he even want to? In this, Faraday can be seen as part of an entire history of scientific endeavour to understand the basic building blocks of matter, and the principles which govern them, as an ultimately simple whole.

The elegant formulation of the unification of electricity and magnetism (electromagnetism) was achieved by James Clerk Maxwell (1831-79). Another figure in the pantheon of Greats, Maxwell held the first professorship of experimental physics at Cambridge in 1871 and made valuable contributions to many areas of physics.

Maxwell explained light in terms of electric and magnetic fields. He demonstrated that a moving magnet induces electric current. When electric current flows, it induces magnetism. His equations showed that the interaction of electricity and magnetism produces waves that propagate through space. He recognised that these waves are light waves. Visible light is just one kind of electromagnetic wave.

On one side of the visible wave band (or spectrum) there are shorter wavelengths such as X-rays and ultraviolet. On the other side, longer wavelengths than visible light produce radio waves bringing us those wonderful interval talks that Old Spider never got to hear. Thinking about the true nature of light produced a controversy that has settled down in the last 100 years into an amiable imponderable.

Paradoxical situations with light bothered a 16 year old German, Albert Einstein (1897-1955). The wedding between the equations of Newton and the equations of Maxwell produced mathematical tears before bed-time. It was obvious to most people that if the formulae needed to be modified, Newton's laws must remain intact; his unimpeachable stature would admit no challenge. Again, the Ockham's razor's glint lay in relinquishing cherished assumptions. Einstein recognised that even sacred cows cannot be milked for ever. Newton's laws would have to bend.