It has been argued by scholars that previous work done by Johannes Kepler was instrumental in the later discoveries of gravity and planetary motion expounded by the British scientist, Isaac Newton. However, although Kepler's laws regarding traditional astronomy were unprecedented, "few astronomers adopted them. There was no Keplerian cosmology or world system as there was Ptolemaic, Copernican, and Tychonic world systems. In many ways, Kepler's work was a historical dead end." [2]
Newton's now infamous epiphany was said to have occurred in the apple orchard of his family home. There under a tree, Newton is said (indeed, he told the story himself in his elder years) to have witnessed an apple falling, and the force of gravity was theorised. As one scholar (comically) noted however, "I'm extremely skeptical about the role of fruit in Newton's life." [3] Fable or not though, Newton's observations and experiments with gravitational force led to the simplification of motions, like velocity and acceleration. More importantly, "it was possible to calculate quantities that are constantly changing.... With this technique, Newton invented an entirely new branch of math called calculus." [4]
Newton also constructed a new and more compact version of a telescope. His refracting telescope, as the instrument is known, is the model used for contemporary telescopes used to peer into the deepest reaches of the visible universe. For Newton, the development served as a launching pad for his scientific career: "It brought Newton on to the world stage of science, and Newton became an overnight sensation." [5]
The greatest work attributed to Newton stems from a visit with the astronomer Edmond Halley. Halley, an astronomer who had studied at Oxford University, analysed the heavens from his colonial workspace on the South Atlantic island of St. Helena, and the most famous comet is named after him. Halley was a prognosticator of planetary orbits and transits, and therefore, an accomplished astronomer to discuss similar work with Newton. [6] During their meeting, Newton surprised Halley by explaining that ellipses formed the line of planetary motion. Though he could not provide documentation of his theory to Halley at the time, Newton devised a rule known as the 'inverse square law' to define this relationship in the heavens. Years of Newton's observations, experiments, and discoveries were published in a book, the Principia, soon after. "It is the most magnificent work, it is the most all-encompassing work, it is the most daring book of any scientific treatise ever written." [7] Within its pages, Newton outlined his three laws of motion, and within these laws, it was evident that the same gravitational forces on Earth operated in space as well: "Newton's breakthrough was to see that the Moon's orbit around the Earth and a cannonball's motion on Earth were governed by the same law of gravity." [8]
"It's so important because it really tells us how nature operates in a fundamentally new way. Newton
is saying, 'the same thing that is going on in the heavens is going on on Earth, and vice versa.' It gives
us a guidebook to answer the age-old question of what causes the rise and fall of the tides. It gives
us answers to the orbits of the planets and their positions. It's a tremendous act of intellectual triumph,
one of the great keystone, cornerstone pieces of our intellectual heritage." [9]
Of course, Newton was not without his critics. His rivalry with fellow scientist (and Royal Society member) Robert Hooke may not as well publicised today, but it was a constant stress for Newton to be exposed to criticism. "As soon as the Principia was published, Newton's old rival, Robert Hooke, claimed he had come up with some of the key ideas first. And later, others attacked it because Newton did not explain what gravity is, just how to calculate its strength." [10] Throughout his life, Newton was never entirely comfortable with publicising his works for fear of shame, ostracising, and negative reaction. [11]
Newton's primary challenge was of the ideas of Rene Descartes, a French philosopher who thought of the universe as a giant machine. Descartes argued that all universal motion was simply "the physical interactions of parts of this machine." [12] For much of the eighteenth century, the theories on physics put forth by Descartes and Newton were the main doctrines for evaluation. The use of different methodologies to come to a respective conclusion may explain part of the divide between British and European science in the second half of the 1700s: "Newton's loyal followers in England made little progress compared to scientists on the continent less tightly tied to geometrical proofs and more ready to take up algebraic methods (developed by Descartes)." [13]
Newton was also fiercely engaged in a copyright battle with the German mathematician and philosopher Gottfried Leibniz, who had also claimed to have invented calculus. Leibniz was a staunch supporter of Descartes' theories on planetary motion, and pitted the two on a fundamental war of physics: vortices vs. elliptical orbits. Leibniz argued that gravity was the result of revolving vortices around the Earth. [14]
Contrary to modern opinion, Newton was not a fervent opponent to the idea of a universe operating under the guise of an omnipotent and omnipresent being. As a member of Trinity College, Newton was expected to pursue theology and work as a Church representative at the University of Cambridge. It was not until a century later that "gangs of interpreters (most of them French) will take the 'God' out of Newton's world." [15] Perhaps this was part of the schism between British science and Continental science in the years following Newton's discoveries. As Newton maintained the idea of a universe with God in it, French and German scientists (like Descartes and Leibniz) attempted to explain a 'godless' universe in the latter years of the Enlightenment.
Another important figure during this time was Christopher Wren, a famous architect from the UK who also had a keen mind for astronomy. Educated at Oxford University, Wren discussed space and the planetary motions with Newton as early as 1677. Wren however, like Hooke, did not possess the mathematical acumen "or geometrical ability to show what orbit would result from an inverse square force of attraction: in effect, to derive Kepler's laws of planetary motion from principles of dynamics." [16]
In my opinion, scientific theories must be documented, tested, and verified multiple times by many reputable contemporaries before they can be recognised as 'discoveries'. This is why we have the 'scientific method' as a process of analysis. It legitimises the work of scientists and allows for the transparent circulation of their ideas amongst the intellectual community and the public at large. Of course, all sorts of problems can and will likely persist - from the destruction of evidence, to accusations of plagiarism, to conflicting research and ethical concerns. All of these possibilities are likely to occur as the work of scientists continues (and some could say, intensifies) in the social, economic, and political arenas of our global world. In Newton's time, these difficulties were even more problematic, as information was not as readily communicable and scientists could be threatened with heresy and put to the death (of course, this can still happen!) As a historian however, it is important to have documented proof of claims so that discoveries can be analysed fairly and attributed to their rightful 'owners'. Therefore, I believe in the scientific method as a necessary process.
End Notes:
[1] Chris Oxley (Director). Smith, George (Dibner Institute) (Contributor). (2005). Newton's Dark
Secrets [YouTube video]. USA: PBS/Nova.
[2] Norriss S. Hetherington. (2006). Planetary Motions. Westport, CT: Greenwood Press, 148.
[3] Oxley (Dir.). Schaffer, Simon (University of Cambridge) (Contr.). Newton's Dark Secrets.
[4] Oxley (Dir.). Abraham, Murray F. (Narrator). Newton's Dark Secrets.
[5] Oxley (Dir.). Speaker unknown. Newton's Dark Secrets.
[6] Hetherington, Planetary Motions, 155: "Halley died before the predicted return of his comet in 1758. He also died before the predicted transits of Venus in 1761 and 1769, abut he left detailed instructions for calculating the size of the solar system from their observation."
[7] Oxley (Dir.). Christianson, Gale (Newton biographer) (Contr.). Newton's Dark Secrets.
[8] Oxley (Dir.). Abraham (Narr.). Newton's Dark Secrets.
[9] Oxley (Dir.). Christianson (Contr.). Newton's Dark Secrets.
[10] Oxley (Dir.). Abraham (Narr.). Newton's Dark Secrets.
[11] Oxley (Dir.). Newton's Dark Secrets.
[12] Oxley (Dir.). Abraham (Narr.) Newton's Dark Secrets.
[13] Hetherington, Planetary Motions, 165-66.
[14] Hetherington, Planetary Motions, 165.
[15] Oxley (Dir.) Schaffer (Contr.) Newton's Dark Secrets.
[16] Hetherington, Planetary Motions, 152.
References:
Hetherington, Norriss S. (2006). Planetary Motions. Westport, CT: Greenwood Press.
Oxley, Chris (Director). (2005). Newton's Dark Secrets [YouTube video]. USA: PBS/Nova. Narrated by Murray F.
Abraham. https://www.youtube.com/watch?v=7n3RWAIlzAI.
-A lot of good information
ReplyDelete- try to put things in your own words and use only 1-2 important quotations since this is a blog
- you can make use of figures (with proper citation) if they help you explain things better