@isaac_newton

Isaac Newton

I work across mathematics, physics, astronomy and optics. My Principia states the laws of motion and universal gravitation, I built calculus, and I showed that white light is a spectrum of colours.

Proof · case studies

Cases

The situation, the work, the outcome. Ranked by how much the work proves.

I cleaned up England's coinage at the Royal Mint

1696 — 1727

Situation

About 20 per cent of coins taken in during the Great Recoinage of 1696 were counterfeit, and convicting coiners was notoriously hard.

Action

Appointed Warden of the Mint in 1696 and Master from 1699, I ran the Great Recoinage, prosecuted 28 counterfeiters and re-engineered minting: weekly output rose from 15,000 to 100,000 pounds and coin weights became far more precise.

Outcome

I brought a scientist's measurement discipline to a government post meant as a sinecure, and the improvements lasted until the 1770s.

public administrationmeasurementcurrency

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I wrote the Principia and unified heaven and Earth

1679 — 1687

Situation

Kepler had described planetary orbits but not why they were ellipses. Exchanges with Robert Hooke and a comet in 1680–81 pushed me back into celestial mechanics; Edmond Halley encouraged and financed publication.

Action

From 1679 I proved that an inverse-square force produces elliptical orbits, then expanded that proof into the Principia (5 July 1687): three laws of motion and universal gravitation, the foundation of classical mechanics and modern physical science.

Outcome

One mathematical law of gravitation explains planets, the Moon, comets, the precession of the equinoxes and Earth's shape — the first great unification in physics and science.

physicsgravitationcelestial mechanics

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I built the first working reflecting telescope

1668 — 1668

Situation

My colour experiments convinced me that any refracting telescope lens disperses light into colours. The Newtonian telescope was the engineering proof of that conclusion.

Action

In late 1668 I built the first known functional reflecting telescope, about eight inches long, grinding my own speculum-metal mirrors to escape the chromatic aberration of lenses. It showed Jupiter's four Galilean moons and the crescent of Venus.

Outcome

When my own research said lenses could not be fixed, I engineered around the problem — new material, new mirror-making technique, working instrument.

opticsinstrument makingengineering

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I built calculus in two years, before anyone else

1664 — 1666

Situation

Cambridge closed for the Great Plague after my BA in August 1665. Working at Woolsthorpe, I developed calculus, optics and gravitation in the same two years.

Action

I began my method of fluxions in 1664; by 20 May 1665 I could compute the tangent and curvature at any point of a continuous curve, and by year's end I had a systematic calculus unifying differentiation and integration.

Outcome

I built the mathematics my physics research needed first — the same calculus later drove the theory of central-force orbits in the Principia.

mathematicscalculusfluxions

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How I prove that colour lives in the light

1666 — 1672

My prism experiments of 1666–1672 showed that white light is a mixture of colours, that a prism refracts each colour by a different angle, and that colour belongs to the light, not to the object. My 1672 paper underpins all later research on colour.

opticsexperimentcolour

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How I averaged away measurement error

1671 — 1700

Measuring Newton's rings in 1671, I averaged all the differences and compared the average with the first ring — a noise-reduction method no one else used then. By 1700 I extended it to equinox timings and wrote the first normal equation of least squares.

statisticsmeasurementexperiment

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Proof · case studies

Cases

The situation, the work, the outcome. Ranked by how much the work proves.

I cleaned up England's coinage at the Royal Mint

1696 — 1727

Situation

About 20 per cent of coins taken in during the Great Recoinage of 1696 were counterfeit, and convicting coiners was notoriously hard.

Action

Outcome

I brought a scientist's measurement discipline to a government post meant as a sinecure, and the improvements lasted until the 1770s.

public administrationmeasurementcurrency

Open card

I wrote the Principia and unified heaven and Earth

1679 — 1687

Situation

Action

Outcome

One mathematical law of gravitation explains planets, the Moon, comets, the precession of the equinoxes and Earth's shape — the first great unification in physics and science.

physicsgravitationcelestial mechanics

Open card

I built the first working reflecting telescope

1668 — 1668

Situation

My colour experiments convinced me that any refracting telescope lens disperses light into colours. The Newtonian telescope was the engineering proof of that conclusion.

Action

Outcome

When my own research said lenses could not be fixed, I engineered around the problem — new material, new mirror-making technique, working instrument.

opticsinstrument makingengineering

Open card

I built calculus in two years, before anyone else

1664 — 1666

Situation

Cambridge closed for the Great Plague after my BA in August 1665. Working at Woolsthorpe, I developed calculus, optics and gravitation in the same two years.

Action

Outcome

I built the mathematics my physics research needed first — the same calculus later drove the theory of central-force orbits in the Principia.

mathematicscalculusfluxions

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How I prove that colour lives in the light

1666 — 1672

opticsexperimentcolour

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How I averaged away measurement error

1671 — 1700

statisticsmeasurementexperiment

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