Sir Isaac Newton PRS (/ˈnjuːtən/;[9] 25 December 1642 – 20 March 1726/7[1]) was

an English physicist and mathematician(described in his own day as a "natural philosopher") who is
widely recognised as one of the most influential scientists of all time and as a key figure in
the scientific revolution. His book Philosophiæ Naturalis Principia Mathematica ("Mathematical
Principles of Natural Philosophy"), first published in 1687, laid the foundations for classical
mechanics. Newton made seminal contributions to optics, and he shares credit with Gottfried
Leibniz for the development of calculus.

Newton's Principia formulated the laws of motion and universal gravitation, which dominated
scientists' view of the physical universe for the next three centuries. By deriving Kepler's laws of
planetary motion from his mathematical description of gravity, and then using the same principles to
account for the trajectories of comets, the tides, the precession of the equinoxes, and other
phenomena, Newton removed the last doubts about the validity of the heliocentric model of the Solar
System. This work also demonstrated that themotion of objects on Earth and of celestial bodies
could be described by the same principles. His prediction that Earth should be shaped as an oblate
spheroid was later vindicated by the measurements of Maupertuis, La Condamine, and others,
which helped convince most Continental European scientists of the superiority of Newtonian
mechanics over the earlier system of Descartes.

Newton built the first practical reflecting telescope and developed a theory of colour based on the
observation that a prismdecomposes white light into the many colours of the visible spectrum. He
formulated an empirical law of cooling, studied the speed of sound, and introduced the notion of
a Newtonian fluid. In addition to his work on calculus, as a mathematician Newton contributed to the
study of power series, generalised the binomial theorem to non-integer exponents, developed
a method for approximating theroots of a function, and classified most of the cubic plane curves.

Newton was a fellow of Trinity College and the second Lucasian Professor of Mathematics at
the University of Cambridge. He was a devout but unorthodox Christian and, unusually for a member
of the Cambridge faculty of the day, he refused to take holy orders in the Church of England,
perhaps because he privately rejected the doctrine of the Trinity. Beyond his work on the
mathematical sciences, Newton dedicated much of his time to the study of biblical
chronology and alchemy, but most of his work in those areas remained unpublished until long after
his death. In his later life, Newton became president of the Royal Society. Newton served the British
government as Warden and Master of the Royal Mint.
 Portrait of Isaac Newton in 1689 (age 46) byGodfrey Kneller

Born 25 December 1642

[NS: 4 January 1643][1]

Woolsthorpe, Lincolnshire,England

Died 20 March 1726/7 (aged 84)

[OS: 20 March 1726

NS: 31 March 1727][1]

Kensington, Middlesex, England

Resting place Westminster Abbey

Residence England

Nationality English


Fields
o Physics

o Natural philosophy


o Mathematics
 o Astronomy


o Alchemy

o Economics

Institutions  University of Cambridge

 Royal Society

 Royal Mint

Alma mater Trinity College, Cambridge

Academic advisors Isaac Barrow[2]

 Benjamin Pulleyn[3][4]

Notable students  Roger Cotes

 William Whiston

Known for  Newtonian mechanics

 Universal gravitation

 Calculus

 Newton's laws of motion


o Optics

o Binomial series


o Principia

o Newton's method

Influences  Johannes Kepler

 Galileo Galilei

 Aristotle

 Henry More[5]

 Polish Brethren[6]

 Robert Boyle[7]

Influenced  Nicolas Fatio de Duillier

 John Keill

 Voltaire

Notable awards FRS (1672)[8]

Early life
Main article: Early life of Isaac Newton

Isaac Newton was born according to the Julian calendar (in use in England at the time) on Christmas
Day, 25 December 1642 (NS 4 January 1643[1]), atWoolsthorpe Manor in Woolsthorpe-by-
Colsterworth, a hamlet in the county of Lincolnshire. He was born three months after the death of his
father, a prosperous farmer also named Isaac Newton. Born prematurely, he was a small child; his
mother Hannah Ayscough reportedly said that he could have fit inside a quart mug.[10] When Newton
was three, his mother remarried and went to live with her new husband, the Reverend Barnabas
Smith, leaving her son in the care of his maternal grandmother, Margery Ayscough. The young Isaac
disliked his stepfather and maintained some enmity towards his mother for marrying him, as
revealed by this entry in a list of sins committed up to the age of 19: "Threatening my father and
mother Smith to burn them and the house over them."[11] Newton's mother had three children from
her second marriage.[12] Although it was claimed that he was once engaged,[13] Newton never
married.

Newton in a 1702 portrait by Godfrey Kneller

From the age of about twelve until he was seventeen, Newton was educated at The King's School,
Grantham which taught him Latin but no mathematics. He was removed from school, and by
October 1659, he was to be found at Woolsthorpe-by-Colsterworth, where his mother, widowed for a
second time, attempted to make a farmer of him. Newton hated farming.[14] Henry Stokes, master at
the King's School, persuaded his mother to send him back to school so that he might complete his
education. Motivated partly by a desire for revenge against a schoolyard bully, he became the top-
ranked student,[15] distinguishing himself mainly by building sundials and models of windmills.[16]

In June 1661, he was admitted to Trinity College, Cambridge, on the recommendation of his uncle
Rev William Ayscough

Optics

In 1666, Newton observed that the spectrum of colours exiting a prism in the position of minimum
deviation is oblong, even when the light ray entering the prism is circular, which is to say, the prism
refracts different colours by different angles.[39][40] This led him to conclude that colour is a property
intrinsic to light—a point which had been debated in prior years.

Replica of Newton's secondReflecting telescope that he presented to the Royal Society in 1672[41]
From 1670 to 1672, Newton lectured on optics.[42] During this period he investigated the refraction of
light, demonstrating that the multicoloured spectrum produced by a prism could be recomposed into
white light by a lens and a second prism.[43] Modern scholarship has revealed that Newton's analysis
and resynthesis of white light owes a debt to corpuscular alchemy.[44]

He also showed that coloured light does not change its properties by separating out a coloured
beam and shining it on various objects. Newton noted that regardless of whether it was reflected,
scattered, or transmitted, it remained the same colour. Thus, he observed that colour is the result of
objects interacting with already-coloured light rather than objects generating the colour themselves.
This is known asNewton's theory of colour.[45]

Illustration of a dispersive prismdecomposing white light into the colours of the spectrum, as discovered by
Newton

From this work, he concluded that the lens of any refracting telescope would suffer from
thedispersion of light into colours (chromatic aberration). As a proof of the concept, he constructed a
telescope using a mirror as the objective to bypass that problem.[46][47] Building the design, the first
known functional reflecting telescope, today known as a Newtonian telescope,[47] involved solving the
problem of a suitable mirror material and shaping technique. Newton ground his own mirrors out of a
custom composition of highly reflective speculum metal, using Newton's rings to judge the quality of
the optics for his telescopes. In late 1668[48] he was able to produce this firstreflecting telescope. In
1671, the Royal Society asked for a demonstration of his reflecting telescope.[49] Their interest
encouraged him to publish his notes, Of Colours,[50] which he later expanded into the work Opticks.
When Robert Hooke criticised some of Newton's ideas, Newton was so offended that he withdrew
from public debate. Newton and Hooke had brief exchanges in 1679–80, when Hooke, appointed to
manage the Royal Society's correspondence, opened up a correspondence intended to elicit
contributions from Newton to Royal Society transactions,[51] which had the effect of stimulating
Newton to work out a proof that the elliptical form of planetary orbits would result from a centripetal
force inversely proportional to the square of the radius vector (see Newton's law of universal
gravitation – History and De motu corporum in gyrum). But the two men remained generally on poor
terms until Hooke's death.[52]

Facsimile of a 1682 letter from Isaac Newton to Dr William Briggs, commenting on Briggs' "A New Theory of
Vision"

Newton argued that light is composed of particles or corpuscles, which were refracted by
accelerating into a denser medium. He verged on soundlike waves to explain the repeated pattern of
reflection and transmission by thin films (Opticks Bk.II, Props. 12), but still retained his theory of 'fits'
that disposed corpuscles to be reflected or transmitted (Props.13). However, later physicists
favoured a purely wavelike explanation of light to account for the interference patterns and the
general phenomenon of diffraction. Today's quantum mechanics,photons, and the idea of wave–
particle duality bear only a minor resemblance to Newton's understanding of light.

In his Hypothesis of Light of 1675, Newton posited the existence of the ether to transmit forces
between particles. The contact with thetheosophist Henry More, revived his interest in alchemy. He
replaced the ether with occult forces based on Hermetic ideas of attraction and repulsion between
particles. John Maynard Keynes, who acquired many of Newton's writings on alchemy, stated that
"Newton was not the first of the age of reason: He was the last of the magicians."[53] Newton's
interest in alchemy cannot be isolated from his contributions to science.[5] This was at a time when
there was no clear distinction between alchemy and science. Had he not relied on the occult idea
ofaction at a distance, across a vacuum, he might not have developed his theory of gravity. (See
also Isaac Newton's occult studies.)

In 1704, Newton published Opticks, in which he expounded his corpuscular theory of light. He
considered light to be made up of extremely subtle corpuscles, that ordinary matter was made of
grosser corpuscles and speculated that through a kind of alchemical transmutation "Are not gross
Bodies and Light convertible into one another, ... and may not Bodies receive much of their Activity
from the Particles of Light which enter their Composition?"[54] Newton also constructed a primitive
form of a frictional electrostatic generator, using a glass globe.[55]

In an article entitled "Newton, prisms, and the 'opticks' of tunable lasers"[56] it is indicated that Newton
in his book Opticks was the first to show a diagram using a prism as a beam expander. In the same
book he describes, via diagrams, the use of multiple-prism arrays. Some 278 years after Newton's
discussion, multiple-prism beam expanders became central to the development of narrow-
linewidth tunable lasers. Also, the use of these prismatic beam expanders led to the multiple-prism
dispersion theory.[56]

Mechanics and gravitation

Newton's own copy of his Principia, with hand-written corrections for the second edition

Further information: Writing of Principia Mathematica

In 1679, Newton returned to his work on (celestial) mechanics by considering gravitation and its
effect on the orbits of planets with reference to Kepler's laws of planetary motion. This followed
stimulation by a brief exchange of letters in 1679–80 with Hooke, who had been appointed to
manage the Royal Society's correspondence, and who opened a correspondence intended to elicit
contributions from Newton to Royal Society transactions.[51] Newton's reawakening interest in
astronomical matters received further stimulus by the appearance of a comet in the winter of 1680–
1681, on which he corresponded with John Flamsteed.[58] After the exchanges with Hooke, Newton
worked out proof that the elliptical form of planetary orbits would result from a centripetal force
inversely proportional to the square of the radius vector (see Newton's law of universal gravitation –
History and De motu corporum in gyrum). Newton communicated his results to Edmond Halley and
to the Royal Society in De motu corporum in gyrum, a tract written on about nine sheets which was
copied into the Royal Society's Register Book in December 1684.[59] This tract contained the nucleus
that Newton developed and expanded to form thePrincipia.

The Principia was published on 5 July 1687 with encouragement andFINANCIAL help
from Edmond Halley. In this work, Newton stated the three universal laws of motion. Together, these
laws describe the relationship between any object, the forces acting upon it and the resulting motion,
laying the foundation for classical mechanics. They contributed to many advances during
the Industrial Revolution which soon followed and were not improved upon for more than 200 years.
Many of these advancements continue to be the underpinnings of non-relativistic technologies in the
modern world. He used the Latin word gravitas (weight) for the effect that would become known
as gravity, and defined the law of universal gravitation.