The Path to Immortality

by Nicholas Mee on October 11, 2017

It is 1697, we enter a dimly lit tavern in one of the less inviting districts of London. Huddled in the shadows we see a man in a loose cloak sitting expectantly with his accomplice at a small table. He has long grey hair, a sharp nose and a determined look in his piercing eyes. This is the Warden of the Royal Mint and he is hoping to interrogate some of the coiners and counterfeiters who, along with many other assorted cutthroats and villains, haunt this alehouse and its environs.

The Tower of London. Credit: Wikimedia – Bob Collowan/Commons/CC-BY-SA-4.0.

Isaac Newton had been appointed Warden—a position worth £300 annually—just the previous year. Modernisation of the coinage was underway. Hand-stamped coins remained in circulation, but the Mint had recently been mechanised and silver and gold coins were now being smelted and stamped in the Tower of London on an industrial scale. The Royal Mint assigned £700 each year simply to remove the dung generated by its horse-powered machinery. Newton declined the accommodation adjacent to the smoke, stench and noise of the factory and army barracks within the walls of the royal fortress, and made his own arrangements in the heart of swinging London. Nevertheless he engaged in little of the high life the capital had to offer. Newton was no enthusiast for the arts, alluding to classical sculptures as ‘stone dolls’ and describing poetry as ‘a kind of ingenious nonsense’. He did visit the opera once in what was the golden age of English opera, the era of Henry Purcell. He recalled: ‘I heard the first act with pleasure, the second act stretched my patience and in the third act I ran away.’

Newton’s alchemical pursuits probably attracted him to the position at the Mint, but he may not have realised his duties extended to the prosecution of coiners, clippers and counterfeiters. Soon after taking on the role, he wrote to the Treasury requesting that a duty ‘so vexatious & dangerous’ not be required of him any longer. Their response was to insist that Newton meet his obligations. With little option but to comply, Newton took to the task with the single-minded determination that he approached all his endeavours.

The Path to Immortality

We find it hard to imagine the father of modern science descending into the underworld vice dens, alehouses and taverns of London and the notorious Newgate prison gathering evidence leading to the prosecution and execution of London’s coiners. It invokes an image common to the world’s mythologies of the hero descending into an underworld realm of horror and depravity where, after overcoming the most arduous ordeals and ultimately death itself, the hero returns with heightened knowledge and self-awareness. The heroes Gilgamesh, Orpheus, Theseus, Heracles, Odysseus and Aeneas all undertook such a journey and their mythical success was proof of their extraordinary powers and the key to their immortality. Newton’s immortality had been established in the much quieter and more genteel surroundings of Trinity College, Cambridge, where a decade earlier in 1687 he published the book that more than any other would forge the modern scientific world. This book, Philosophiæ Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy) is usually known as The Principia (pronounced with a hard ‘c’).

Great Court, Trinity College, Cambridge. Credit: Wikimedia – Cmglee.

Isaac Newton entered Trinity College in 1661 as an 18 year old student. In August 1665 the university closed due to an outbreak of plague and Newton returned home to Woolsthorpe Manor in Lincolnshire. Newton remained at home for the next two years and it was during this period that he developed his early ideas that would lead to a complete transformation of science and the wider world. There is a famous and memorable image of the young Newton musing on the force of gravity after seeing an apple fall in the garden of the manor house. Although this sounds an unlikely story, it was told by Newton himself. Newton lived his last seven years with his niece Catherine Barton and her husband John Conduitt, who also assisted Newton at the Royal Mint. Conduitt recorded the following account of Newton’s story:

‘In the year 1666 he retired again from Cambridge to his mother in Lincolnshire. Whilst he was pensively meandering in a garden it came into his thought that the power of gravity (which brought an apple from a tree to the ground) was not limited to a certain distance from earth, but that this power must extend much further than was usually thought. Why not as high as the Moon said he to himself & if so, that must influence her motion & perhaps retain her in her orbit, whereupon he fell a calculating what would be the effect of that supposition.’

Newton realised that if we throw an apple it will follow an arc as it is drawn towards the ground by gravity. We can imagine firing an apple or a cannonball from a mountain top. The faster we propel the cannonball the further it will travel before it hits the ground. Newton reasoned that if it were propelled with sufficient velocity it would circle the Earth completely, like the Moon, without ever touching the ground—it would be in orbit. Newton illustrated this idea with the figure on the left which is taken from the Principia. We are so familiar with the notion that the force that pulls an apple to the ground is the same as the force that holds the planets in orbit that it is hard to conceive of a time when this was not common knowledge. But prior to the Newtonian revolution, less than 350 years ago, the connection between the fall of an apple and the celestial dance of the planets was completely unknown.

The Scientific Revolution

Newton offered far more than an analogy and a convincing argument. He produced a complete system of mechanics and gravity that could be used to calculate how the material world operates. Newton’s ideas were applied far and wide by subsequent generations and became the foundation for the entire scientific enterprise of understanding the universe. Newton’s theories reigned supreme for over 200 years.

Saturn’s beautiful rings held within the planet’s orbital embrace. Credit: ESA.

It was not until the early years of the 20th century, that modifications to Newton’s theories would be found necessary. We now know that quantum theory is required when analysing the very small, special relativity when objects are moving close to the speed of light, and general relativity when considering the gravitational effect of extremely massive bodies.

Warping Space and Time

In 1915, Einstein devised a theory of gravity—general relativity—that works even better than Newton’s. Einstein did away with Newton’s force of attraction between massive bodies. He proposed, instead, that each massive body warps space and time in its vicinity and this affects the path of any other objects that move close by, including light. Although these descriptions sound completely different, the predictions of the two theories are very similar unless the bodies are extremely massive.

Rather remarkable conclusions follow from general relativity when applied to intense gravitational environments. General relativity implies that massive objects bend the path of light and objects such as giant elliptical galaxies and galaxy clusters warp space so much they act like enormous gravitational lenses. The illustration below shows an example where the light from a distant galaxy is warped into a circle by the intervening giant elliptical galaxy seen within the ring. Another consequence is the existence of black holes—objects whose gravitational attraction is so severe that even light cannot escape. General relativity also predicts that incredibly violent events, such as black hole collisions and mergers, generate ripples in the fabric of space known as gravitational waves. All these outlandish predictions are now known to be correct.

Gravitational lens – LRG 3-757 discovered in data from the Sloan Digital Sky Survey (SDSS). Credit: ESA/NASA/HST.

Newtonian gravity works incredibly well. It is perfectly adequate in almost all circumstances. In the vicinity of the Earth, the differences between Newtonian gravity and general relativity are tiny, so we might expect them to be irrelevant in every day life. It is quite surprising, therefore, that we now daily use a technology that relies on general relativity for its accuracy. Gravitational time distortion is built into the GPS (Global Positioning System) used for satellite navigation. GPS could not function for more than a few minutes, if the predictions of general relativity were not incorporated into the system.

Sir Isaac Newton

Newton succeeded in his crackdown on abuse of the British coinage and was personally responsible for 28 convictions. He was appointed Master of the Royal Mint in 1699, and six years later when knighted by Queen Anne it was for his work at the Royal Mint rather than his scientific achievements. In 2017, the Royal Mint issued a 50p coin to mark the 375th anniversary of Newton’s birth.


Further Information

There is a lot more about Newton and the development of his ideas about gravity in my book: Gravity: Cracking the Cosmic Code.

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