The masters of heavenly geometry

Astronomy pioneers Isaac Newton and Edmund Halley made crucial contributions to our understanding of the heavens. Discover how two Fellows of the Royal Society set the stage for many subsequent discoveries.

Portrait of Isaac Newton (1727) by John Vanderbank (1694-1739)The Royal Society

Sir Isaac Newton, giant of science 

Isaac Newton (1642-1727) made substantial practical and theoretical contributions to astronomy. His laws of motion and gravity lay the foundations for a superior understanding of the physical universe. His 1660s experiments on light and colours went alongside his development of reflecting telescopes.

Reflecting telescope, designed and made by Isaac Newton (c. 1671) by Isaac Newton (1643-1727)The Royal Society

Newton created astronomical instruments himself. In 1673, he sent a model of his newly invented reflecting telescope to the Royal Society. The telescope used a speculum mirror to gather light.

This version, much restored, was also made by Newton. It was presented to the Royal Society in 1766.

Newton's Telescope and Hubble - Objectivity #16 (2015-04-20) by James Hennessy and Brady HaranThe Royal Society

Portrait of Edmond Halley (1736) by UnknownThe Royal Society

Sir Edmond Halley: Astronomer Royal and voyager 

Edmond Halley (1656-1742) was a key player in observational and theoretical astronomy. As well as computing the orbit of the comet now named after him - 1P/Halley - he set up an observatory in the southern hemisphere at St Helena, observed a transit of Mercury and deduced the transit of Venus. In 1720, Halley became the second Astronomer Royal, succeeding John Flamsteed (1646-1719).

Halley holds a drawing of his model of the interior of the Earth, deduced from Newton's value for lunar density.

Edmund Halley (1735) by George White after Sir Godfrey KnellerNational Gallery of Art, Washington DC

Halley called upon Newton’s expertise to tackle a puzzle of the night sky – the appearance and orbits of comets.

Halley was the first to calculate the orbit and trajectory of the comet that now bears his name. The comet is visible from Earth every 74-79 years.

On Newton's Principia (1687) by Edmond Halley (1656-1742)The Royal Society

Halley persuaded Newton to print and share his laws of the universe with other scientists, giving rise to Principia Mathematica (1687).

In this letter, Halley’s appreciation of Newton's Principia Mathematica begins: “This incomparable Author, having at length been prevailed upon to appear in publick…”

Philosophiae Naturalis Principia Mathematica, by Isaac Newton (1685) by Isaac Newton (1643-1727)The Royal Society

The Royal Society holds the original manuscript of Newton's Principia that was sent to the printer for publication.

In the volume, Newton proposes a universal law of gravitation and explains the nature of elliptical orbit. But the ground-breaking volume almost didn't get published...

Newton's Principia Manuscript - Objectivity #100 (2016-12-20) by James Hennessy and Brady HaranThe Royal Society

Beet SugarLIFE Photo Collection

William Blake (1757-1827) was critical of reductive scientific thought. In this picture, the straight lines and sharp angles of Newton’s profile suggest that he cannot see beyond the rules of his compass. Behind him, the textured rock may be seen to represent the creative world, to which he is blind.

Isaac Newton after William Blake's monotype by Eduardo Paolozzi (1924-2005)The Royal Society

Lasting legacy

Newton and Halley contributed greatly to astronomy by developing scientific methods for the observation, description and analysis of the heavens. Although both men recognised that they could not explain the cause of gravity and other phenomena they described, their influence on astronomy was crucial, in that they demonstrated scientifically what gravity did. Today gravity is understood and accepted, and Isaac Newton remains the master of heavenly geometry.

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