David Kaiser writes:
The Austrian polymath Ernst Mach exhorted his fellow physicists in the early 1880s to recognise that all was not well with their discipline. Two hundred years earlier, Isaac Newton had bequeathed to them a remarkable system of laws which made it possible for them to describe – and predict – the motion of everything from an apple falling from a tree near Woolsthorpe to the orbit of the Moon around the Earth. When Mach was still a child, it had been concluded on the strength of Newton’s laws that there must be an as yet unseen planet in the solar system, its presence deduced from subtle wobbles in the orbit of Uranus. In 1846, the discovery of Neptune was celebrated across Europe as one more victory for Newtonian physics.