Category Great Personalities

Newton was invited to join the Royal Society in early 1672. The Society had distinguished personalities such as Robert Boyle and Christopher Wren as its members at the time. Newton had seen the invitation to join as a great honour.

He found a rival of his rank at the Society. It was Robert Hooke, who had been a member of the Royal Society right from its start. Hooke was a brilliant and inventive man whose mind moved from discipline to discipline, making discovery after discovery.

Though Hooke was mainly interested in mechanics, he built amazing microscopes and researched the structure of the plant cell. He was also a gifted inventor who created dozens of devices ranging from an early form of the telegraph to a diving bell.

He had also ventured into the study of combustion, musical notes and the nature of light, the last of which became the bone of contention between Hooke and Newton. The conflict between the duo began with conflicting opinions about the nature of white light. Newton presented his first paper to the Royal Society in February 1672, in which he detailed his work on the nature of light and advanced his theory that white light was a composite of all the colours of the spectrum. Newton asserted that light was composed of particles.

Hooke had his own ideas about the nature of light. He believed that light travelled in waves, in contradiction to Newton’s belief. Hooke was critical of Newton’s paper.

He went on to attack Newton’s methodology and conclusions. Hooke was certainly not the only person to take a critical stand. Huygens, the great Danish scientist and a number of French Jesuits also raised objections. However, due to his work in the same field and prominence within the society, Hooke’s remarks were the most cutting.

Newton responded to the criticism by being angry and defensive. This came to be his characteristic response to any critique of his work.

The Royal Society was the leading national organization for the promotion of scientific research in Britain. It is also the oldest national scientific society in the world.

The origin of the society can be traced back to November 28, 1660, when twelve men met. They decided to set up a College for promoting ‘Physico-Mathematicall Experimentall Learning’. These men included scientist Robert Boyle, architect Christopher Wren, Bishop John Wilkins and the courtiers Sir Robert Moray and William, 2nd Viscount Brouncker.

Brouncker went on to become the first president of the Royal Society. King Charles II granted a royal charter for it as ‘The Royal Society’. Through the royal charter the society got an institutional structure- a president, treasurer, secretaries, and council. The society has always remained a voluntary organization, independent of the British state despite receiving royal patronage from the beginning.

The conduct and communication of science was revolutionized by the Society. In 1665 itself, Hooke’s Micrographia and the first issue of Philosophical Transactions were published. Philosophical Transactions is now the oldest continuously-published science journal in the world.

The Royal Society also published Isaac Newton’s Principia Mathematica, and Benjamin Franklin’s kite experiment demonstrating the electrical nature of lightning.

Newton was a mathematics professor at Trinity College, Cambridge. But he was not a successful teacher. Newton preferred to spend his time alone in the laboratory, which he built himself, or in the small garden outside his rooms.

Only a few students attended his classes and fewer still understood what he said. A secretary later commented that often, Newton ended up teaching his walls with no students in front of him!

Not even one student who studied mathematics under Newton in the thirty years of his teaching career dedicated himself to the study of mathematics.

Newton’s absent-mindedness was also well known. He would sometimes stay in bed an entire day pondering upon a particular problem. If he received visitors while he was immersed in a new idea, Newton would simply walk into another room to continue thinking; completely forgetting that somebody was awaiting him in the other room.

By the 1670s, Trinity College became a lonely place for him. He enjoyed the brotherhood of similar minds and hence, he eagerly accepted the offer to join the Royal Society.

The English version of Opticks: or A Treatise of the Reflexions, Refractions, Inflexions and Colours of Light was published in 1704. A Latin translation of the book appeared in 1706. This is Newton’s second major book on physical science. It analyses the fundamental nature of light.

The book covers discoveries and theories concerning light and colour made by Newton in 33 years. It deals with ideas ranging from the spectrum of sunlight to the invention of the reflecting telescope. It also includes the first workable theory of the rainbow and the first colour circle in the history of colour theory. Newton also discusses various other subjects such as metabolism, blood circulation and a study of the haunting experiences of the mentally ill.

One of the major impacts of Opticks was that it overthrew the idea that ‘pure’ light (such as sunlight) is white or colourless, and it becomes coloured by mixing with darkness caused by interactions with matter. Newton showed that this assumption from the time of Aristotle and Theophrastus was wrong.

Newton also illustrated that colour is a result of the physical property of light, as each hue is refracted at a characteristic angle by a prism or lens. He also added that colour is a sensation within the mind and not an inherent property of material objects or of light itself. Considering the impact of the book on science, it is astonishing to think that it was initially published anonymously with just the initials I.N. at the end of an advertisement at the front of the book.

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Astronomer Edmond Halley persuaded Newton to expand his studies. Halley was the driving force behind the publication. He acted as a critic as well as supporter for this work.

Edmond Halley even convinced Newton to allow him to edit the Principia. Halley covered the various expenses, corrected the proofs himself, and ultimately got Philosophiae Naturalis Principia Mathematica printed in 1687.

Newton was famously reluctant to publish his works. Without Edmond Halley’s compulsion to publish Principia, Newton may have never become an outstanding figure in the history of science.

Newton would probably be known only for his mathematics and optics, and remain a relatively obscure professor in Cambridge.

Philosophiae Naturalis Principia Mathematica (Latin for Mathematical Principles of Natural Philosophy) is often simply referred to as Principia. This work in three books, written by Isaac Newton in Latin was first published on 5 July 1687. In retrospect, its publication was a landmark event in the development of modern physics and astronomy.

Newton published two more editions in 1713 and 1726 after annotating and correcting his personal copy of the first edition. Principia contains the laws of motion, law of universal gravitation and a derivation of Kepler’s laws of planetary motion (Kepler originally obtained these empirically). The work also forms the foundation of classical mechanics. Principia is considered as one of the most important works in the history of science.

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The significance of the Newtonian reflector does not lie in the discovery of new celestial bodies or celestial phenomena. Newton neither discovered the moons around Jupiter like Galileo nor did he plot the return of a comet – like Halley. However, the Newtonian reflector and Newton’s theory of universal gravitation made an invaluable contribution: they tied together Mathematics, Astronomy, and our understanding of the universe.

He mathematically established that gravitation was a two-way operation. While the Earth pulled on a falling apple, the apple too pulled on Earth. This was seen, calculated and confirmed in the motions of heavenly bodies. It was made possible by the science of the reflector telescopes which can be credited to Newton. The work of Copernicus and Galileo were carried through by Newton and his telescope.

While it is commonly assumed that Newton invented the first reflector telescope, claims to the contrary are also there. The Italian monk Niccolo Zucchi claimed to have experimented with the idea as far back as 1616. It is possible that Newton read James Gregory’s 1663 book Optica Promota which contained designs for a reflecting telescope using mirrors. Gregory had been trying to build such a telescope, but he did not succeed. Ultimately, Newton’s telescope was the one that worked well and brought reflectors to the scientific world.

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The first successful practical reflecting telescope was built by Newton. Until then telescopes were large unwieldy instruments. The design of the telescope was recast by Newton on the basis of his theory of optics. He used mirrors instead of lenses and the result was a new telescope 10 times smaller than the traditional ones.

Earlier also many efforts were made to make more powerful telescopes using larger lenses. They were unsuccessful as the lens kept producing coloured rainbows around bright objects like the Moon and the planets. The coloured fringes formed due to the unequal refraction of colours by the lens were unavoidable in simple telescopes.

Newton was under the assumption that no lens could rectify this issue. Though this was a mistaken assumption, it led him to use a mirror to form an image and thereby to build a reflecting telescope. This is now called the Newtonian reflector. A curved mirror brings rays of light to a focus and forms an image by reflection (whereas a lens does it by bending or refraction). Some of the largest telescopes used today are based on the telescope made by Newton in 1668.

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The laws of motion are applicable even in outer space. Newton’s Second Law states that force is needed to increase or decrease the speed of a body. This implies that astronauts must learn to push themselves through their spacecraft, or else they will float around helplessly. They also need to remember to stop themselves as they near their destination or else they’ll keep moving till they hit something.

During their first attempt, astronauts usually end up a little worse for the wear after stumbling around the spacecraft. Unlike humans, animals flown to space often fail to learn this. A set of new-born quails aboard Russia’s Mir space station couldn’t adapt to life in space and died in a few days. Newton’s Third Law too has application for astronauts. The law states that for every action, there is an equal and opposite reaction. While turning a screw, astronauts have to anchor themselves to a wall, or else they’ll be the ones twisting. Even the mildest action like typing at a computer keyboard will send an astronaut floating away. To remedy this problem, workstation on the international space station has restraining loops for the crew to anchor their feet.

Though it may seem like the laws of motion are different in space and on Earth that is not the case. The overwhelming force of Earth’s gravitational field simply masks its exact effects. Gravity plays an astonishing part in many phenomena we take for granted. For instance, hot air (which is lighter than cool air) rises, and a convection current is formed which enables natural air circulation in our houses. In space however, nothing is lighter than anything else and ordinary convection currents do not exist. Thus, to make sure that the astronauts don’t suffocate due to carbon dioxide accumulation, a ventilation fan is installed to facilitate air circulation.

The International Space Station is a perfect example of the laws of motion. Though intuition and common-sense points otherwise, Newton realized that a bullet shot from a gun should continue to move indefinitely. On Earth, atmospheric friction slows the projectile while gravitational force pulls it to the ground. But the faster the bullet is shot, the farther it will travel before falling. And if you can manage to shoot something at a speed of around 11.2 km/s, it will never finish its trajectory. It will instead orbit the Earth in a state of perpetual free fall. This particular velocity (11.2 km/s) cancels the pull of Earth’s gravity and is used to launch spacecraft.

Even fire is not exempt from the laws of motion in space. Behaviour of weightless flames is rather different from those on Earth. However, such a fire is best limited to the lab as fire aboard a spacecraft can have catastrophic effects.

The sizes of rockets range from small fireworks used by ordinary people to massive Saturn Vs that once carried payloads toward the Moon. Newton’s third law of motion explains the propulsion of all rockets, jet engines, deflating balloons, and even the movement of squids and octopuses.

The engines of rockets need to overcome both the pull of gravity and the inertia of the rocket as stated in the first law. According to Newton’s Third Law, “every action has an equal and opposite reaction”. A rocket is pushed forward by the push of the burning fuel at its front. This also creates an equal and opposite push on the exhaust gas backwards.

Once they’re in motion, they won’t stop until a force is applied. As per Newton’s second law, as mass of the object increases, the force needed to move it also increases. The larger a rocket, the stronger the force (for instance, more fuel) to make it accelerate. A space shuttle requires around three kilograms of fuel for every kilogram of payload it carries.

Astronauts in space must also keep the laws of motion in mind. During his pioneering orbit of the Earth in 1961, Russian cosmonaut Yuri Gagarin was the first to experience the practical effects. Gagarin put down his pencil while writing his log. In keeping with Newton;s first law, by which the planets move around the Sun, the pencil floated out of reach. He ended up completing the log using a tape recorder. Now astronauts keep their equipment tethered to a surface with Velcro or bungee straps.

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