**Who was he and what is he most famous for?**

Born in 1643, Sir Isaac Newton was a highly influential English mathematician, astronomer, physicist, alchemist, and theologian. He is widely recognised as one of the most important scientists of all time having devised numerous theories and philosophies, the most celebrated of these being the discovery of the law of gravity and the Laws of Motion.

His work *Principia Mathematica* laid the framework for the Scientific Revolution of the Seventeenth Century. This is quite an unforeseen achievement when you learn that he was born into the world over 11 weeks early and wasn’t expected to survive.

The legend is that he discovered the law of gravity while sitting in his garden one day when an apple fell on his head inspiring him to come up with the theory. We don’t know if this is actually true, but we do know that being an astronomer, he was already fascinated by the orbit of the Moon around the Earth (Laws of Motion). After seeing how apples always fall straight to the ground instead of sideways or upwards, he spent several years working on the mathematics showing that the force of gravity decreased as the inverse square of the distance. In short, the apple draws the Earth, as well as the Earth, draws the apple.

Newton’s three laws of motion relate the forces acting on a body to its motion. The first is the law of inertia, it states that ‘every object in motion will stay in motion until acted upon by an outside force’. The second is commonly stated as ‘force equals mass times acceleration’, or F = ma. The third and final law is commonly known as ‘to every action there is an equal and opposite reaction’.

You’re probably familiar with the term newton (N) in physics. Named after Sir Isaac Newton, this is the metric unit of force.

**Did you also know?**

Newton built the first practical reflecting telescope and developed a sophisticated theory of colour based on the observation that a prism decomposes white light into the colours of the visible spectrum.

He was a fellow of Trinity College in Cambridge and the second Lucasian Professor of Mathematics at the University of Cambridge. Beyond his work on the mathematical sciences, Newton dedicated much of his time to the study of alchemy and biblical chronology, but most of his work in those areas remained unpublished until long after his death. He was knighted by Queen Anne in 1705 and he spent the last three decades of his life in London, serving as Warden (1696–1700) and Master (1700–1727) of the Royal Mint (where he oversaw the production of the Pound Sterling) as well as president of the Royal Society (1703–1727). He died on 31^{st} March 1727 at the aged of 85.

**Other mathematical achievements of Newton include:**

- Generalised binomial theorem
- Newton’s identities
- Newton’s method
- Classified cubic plane curves (polynomials of degree three in two variables)
- Substantial contributions to the theory of finite differences
- Use of fractional indices
- Used geometry to derive solutions to Diophantine equations
- Used power series with confidence and to revert power series
- Discovered a new formula for pi

**Newton is well-known for these sayings:**

- ‘Plato is my friend – Aristotle is my friend – but my greatest friend is truth’.

- ‘Truth is ever to be found in simplicity, and not in the multiplicity and confusion of things’.

- ‘If I have seen further it is only by standing on the shoulders of Giants’.