The Restless universe
|Introduction to The restless Universe|
1 The lawful Universe2 The clockwork Universe
Other titles in the Physical World series
4 The intangible Universe
4.1 Electromagnetism and fieldsPart 1 of 4 | Part 2 | Part 3 | Part 4For a printable version of 'The intangible Universe' click here
When Newton wrote about 'The System of the World' in Part 3 of Principia, the only forces he could discuss in any detail were the contact forces that arose when one object touched another, and gravity, which acted at a distance. Even so, Newton thought that there were other forces at work in the world, and hoped they might eventually be brought within his overall scheme just as gravity had been. In fact, Newton wrote:'I wish we could derive the rest of the phenomena of Nature by the same kind of reasoning from mechanical principles, for I am induced by many reasons to suspect that they may all depend upon certain forces by which the particles of the bodies, by some causes hitherto unknown, are either mutually impelled towards one another, and cohere in regular figures, or are repelled and recede from one another.'
Isaac Newton (1686), Principia.
Amongst the phenomena familiar to Newton, but which he could not treat mathematically, were those of electricity and magnetism, both of which had been known since antiquity
Figure 1.16 Examples of electric and magnetic forces
Continue on to Electromagnetism and fields, part 2 of 4
Relevant LinksA note on powers of ten and significant figures
|S207 The Physical World|