Friday 6 January 2017

Electromagnetism

Carlo Rovelli, Reality Is Not What It Seems (Allen Lane, 2016), pp. 41-47.

Faraday intuited that "...an entity diffused throughout space...is modified by electric and magnetic bodies and...acts upon..." them. (p. 41) This entity is a field consisting of many infinitely thin lines of force. Maxwell wrote equations that describe these lines of force.

The electromagnetic force:

holds electrons in atoms;
holds atoms in molecules;
makes chemistry, organisms and neurons work.

(I thought that the four forces of nature were gravity, electromagnetism and the strong and weak nuclear forces but here Rovelli describes just two.)

Maxwell's equations predict that lines of force undulate. The speed of their undulations, when calculated, was the same as for light because light is undulating electromagnetic radiation and color is different wavelengths. Maxwell also predicted invisible wavelengths which include radio. Thus, a technological revolution:

radio
television
telephones
computers
satellites
wi-fi
the internet

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