Biografi tokoh-tokoh fisika terkenal sepanjang masa

Biografi Isaac Newton

• Lahir : 4 Jan 1643 di Woolsthorpe, Lincolnshire, Inggris
• Meninggal : 31 Maret 1727 di London, Inggris
• Orang tua :

• Ayah : Isaac Newton (meninggal pada  bulan Oktober 1642, tiga bulan        sebelum kelahiran Newton)
• Ibu     : Hannah Ayscough
• Ayah tiri: Barnabas Smith, seorang menteri di gereja ( di North Witham).                  Menikahi ibunya saat Newton berumur dua tahun.
• Nenek: Margery Ayscough
• Kakek: James Ayscough

Isaac Newton mungkin merupakan salah satu dari sedikit ilmuwan yang paling berpengaruh yang pernah hidup. Newton berasal dari sebuah keluarga petani, walaupun ayahnya meninggalkan harta yang cukup, tetapi dia tidak mengenyam pendidikan semasa kecilnya, menuliskan namanyapun tidak bisa.

Setelah ibunya menikah lagi, dia tinggal bersama nenek dan kakenya tetapi keduanya tidak memberikan kasih sayang sebagaimana mestinya, masa kecilnya sungguh tidak bahagia. Dia sangat kecewa terhadap ibu dan ayah tirinya, sampai-sampai dia mengungkapkan bahwa “Threatening my father and mother Smith to burn them and the house over them“.

Setelah ayah tirinya meninggal, Newton tinggal bersama ibunya lagi, dan juga nenek beserta adik tirinya,setelah itu newton dikirimkan ke sekolah bahasa di daerah Grantham dimana dia akhirnya menjadi anak terpandai di sekolahnya. Saat bersekolah di The Kings School di Grantham. Dia tinggal di-kost milik apoteker lokal yang bernama William Clarke. Tetapi keluarganya mengeluarkan Newton dari sekolah dengan alasan agar dia menjadi petani saja, bagaimanapun Newton terlihat tidak menyukai pekerjaan barunya. Tapi pada akhirnya setelah meyakinkan keluarga dan ibunya dengan bantuan paman, William Ayscough, dan gurunya, Newton dapat melanjutkan sekolahnya di The Kings School di Grantham. Saat itu dia tinggal bersama kepala sekolahnya, Stokes. Pada akhirnya dia menamatkan sekolah pada usia 18 tahun dengan nilai yang memuaskan. Setelah itu, Stokes berhasil membujuk ibunya agar Newton melanjutkan pendidikannya di universitas.

Pada tanggal 5 Juni 1661, Newton memasuki Trinity College Cambridge untuk melanjutkan pendidikannya. Di kampusnya Newton mempelajari filosofi dari Descartes, Gassendi, Hobbes, dan juga Boyle. Dia tertarik untuk mempelajari teori Copernicus dari Galileo, dan juga teori optiknya Kepler. Dia menulis sebuah buku yang berjudul Quaestiones Quaedam Philosophicae (Certain Philosophical Questions). Newton mulai tertarik untuk mempelajari matematik pada musim gugur tahun 1663, karena dia ingin mempelajari buku astronomi yang telah dibelinya. Karena dia merasa tidak memahami geometri sehingga memutuskan untuk mempelajari buku Euclid's Elements. Newton memperoleh beasiswa pada tanggal 28 April 1664 dan memperoleh gelar bachelor pada April 1665.

Newton was a law unto himself. He kept large amounts of his work to himself for years because he was worried about publishing it and being criticised - he couldn't stand criticism. He would attack anyone who didn't agree with him and hid many of his ideas away from other people. He had few friends - but gave a number of young mathematicians and scientists time and financial support. He suffered from depression at times, and yet could be delightful. He didn't believe in Christianity, yet for years was supposed to be training to be ordained as a priest. He lived for 85 years and died in agony from stones in his bladder. He refused the last sacrament on his deathbed, but is buried in state in Westminster Abbey.

2.2 Apa yang telah dilakukan Newton ?

            Sebelum Newton berumur 25 tahun, dia telah menguasai bidang matematika, optik, fisika, dan astronomi.

While Newton remained at home he laid the foundations for differential and integral calculus, several years before its independent discovery by Leibniz. The 'method of fluxions', as he termed it, was based on his crucial insight that the integration of a function is merely the inverse procedure to differentiating it. Taking differentiation as the basic operation, Newton produced simple analytical methods that unified many separate techniques previously developed to solve apparently unrelated problems such as finding areas, tangents, the lengths of curves and the maxima and minima of functions. Newton's De Methodis Serierum et Fluxionum was written in 1671 but Newton failed to get it published and it did not appear in print until John Colson produced an English translation in 1736.
When the University of Cambridge reopened after the plague in 1667, Newton put himself forward as a candidate for a fellowship. In October he was elected to a minor fellowship at Trinity College but, after being awarded his Master's Degree, he was elected to a major fellowship in July 1668 which allowed him to dine at the Fellows' Table. In July 1669 Barrow tried to ensure that Newton's mathematical achievements became known to the world. He sent Newton's text De Analysi to Collins in London writing:-
[Newton] brought me the other day some papers, wherein he set down methods of calculating the dimensions of magnitudes like that of Mr Mercator concerning the hyperbola, but very general; as also of resolving equations; which I suppose will please you; and I shall send you them by the next.
Collins corresponded with all the leading mathematicians of the day so Barrow's action should have led to quick recognition. Collins showed Brouncker, the President of the Royal Society, Newton's results (with the author's permission) but after this Newton requested that his manuscript be returned. Collins could not give a detailed account but de Sluze and Gregory learnt something of Newton's work through Collins. Barrow resigned the Lucasian chair in 1669 to devote himself to divinity, recommending that Newton (still only 27 years old) be appointed in his place. Shortly after this Newton visited London and twice met with Collins but, as he wrote to Gregory:-
... having no more acquaintance with him I did not think it becoming to urge him to communicate anything.

Kita mengenal akrab nama ini dari teorinya tentang gravitasi. Namun demikian gravitasi bukanlah satu-satunya penemuan Newton yang monumental. Newton juga mewariskan kepada kita konsep tentang spektrum cahaya (dia yang pertama menemukan bahwa cahaya putih ternyata merupakan gabungan dari spektrum yang terdiri dari warna-warni pelangi). Ia juga tercatat sebagai penemu teleskop refleksi (nama "Refleksi" untuk weblog ini sebenarnya saya pilih atas karena mengingatkan saya atas teleskop tersebut). Begitu pula dengan hukum geraknya yang mampu menjelaskan banyak hal mengenai orbit benda-benda angkasa, termasuk bumi kita.

Soal lahirnya hukum gravitasi ini memang memiliki banyak versi. Ada yang percaya bahwa gagasan tentang gravitasi muncul setelah sebuah apel jatuh menimpa kepalanya. Versi lain menyatakan bahwa sumber gagasan justeru saat ia melihat bulan yang menggantung di angkasa. Dalam biografinya malahan dikisahkan bahwa gagasan soal teori gravitasi lahir setelah ia teringat akan sebuah permainan di masa kecilnya: Sebuah ember penuh berisi air diputar kuat-kuat dalam sumbu vertikal sehingga air dalam ember tidak tumpah walaupun dalam posisi ember yang terbalik.

Membaca biografi Isaac newton memang sangat mengasyikkan. Banyak hal yang memberikan inspirasi dari pribadi ilmuwan yang satu ini--walaupun sebagai manusia ia tidak luput dari berbagai kekurangan. Ketekunannya yang luar biasa, rasa ingin tahunya yang besar, ketelitiannya dalam melakukan riset adalah beberapa diantaranya.

Kini, lebih dari tiga ratus tahun setelah Newton merumuskan teori-teorinya, penemuannya masih tetap relevan. Semasa hidupnya, Newton mungkin tidak pernah membayangkan bahwa peluncuran roket dan perjalanan antar planet kini bisa dilakukan dengan berdasar kepada rumusan yang ia temukan. Minggu lalu, disini saya pernah cerita tentang penemuan planet ekstrasolar. Kalau mau jujur, sebenarnya orang yang paling berperan dalam penemuan ini adalan Newton. Bukankah konsep tentang spektrum cahaya yang digunakan untuk mengukur pergeseran Doppler (sehingga terlihat adanya 'goyangan' pada sebuah bintang) merupakan buah dari penemuan Newton? Hukum gravitasinya menjelaskan bagaimana sebuah planet yang mengorbit bisa mempengaruhi bintang induknya. Dan jangan lupa dengan hukum gerak yang menjelaskan tentang periode, massa, dan jarak objek yang mengelilingi sebuah bintang. Semua itu lahir dari otak ilmuwan jenius itu tiga setengah abad lampau!

Issac Newton saat berusia 46 tahun pada lukisan karya Godfrey Kneller tahun 1689

, Newton mengembangkan teori kalkulus. Newton merupakan orang pertama yang menjelaskan tentang teori gerak dan berperan penting dalam merumuskan gerakan melingkar dari hukum Kepler, dimana Newton memperluas hukum tersebut dengan beranggapan bahwa suatu orbit gerakan melingkar tidak harus selalu berbentuk lingkaran sempurna (seperti elipse, hiperbola dan parabola). Newton menemukan spektrum warna ketika melakukan percobaan dengan melewati sinar putih pada sebuah prisma, dia juga percaya bahwa sinar merupakan kumpulan dari partikel-partikel. Newton juga mengembangkan hukum tentang pendinginan yang di dapatkan dari teori binomial, dan menemukan sebuah prinsip momentum dan angular momentum.

Pendapat Kepala Akademi Ilmiah Berlin tentang Newton: "Newton ialah seorang jenius besar yang pernah ada dan paling beruntung, yang tak bisa kita temukan lebih dari suatu sistem dunia untuk didirikan." [See Shapley.]

2.3 Karya- karya Newton

• Optik

Penemuannya yang pertama adalah tentang cahaya. Dulu orang beranggapan warna putih merupakan warna tunggal atau warna murni. Tapi, lewat serangkaian percobaan, Newton menemukan sekaligus membuktikan, warna putih merupakan campuran dari tujuh warna berbeda yang sama dengan warna-warna pelangi, yaitu merah-jingga-kuning-hijau-biru-nila-ungu (Mejikuhibiniu). Teori ini kemudian dikenal dengan istilah Pembiasan Cahaya. Tak hanya puas dengan penemuan pembiasan cahaya, Newton membuat percobaan lain yang masih ada hubungannya dengan cahaya. Kali ini ia melakukan pemantulan cahaya, kemudian Newton berhasil membuat sebuah benda yang bernama teropong refleksi.

• Mekanika dan Gravitasi

Setelah penelitian di bidang cahaya, Newton kemudian mendalami bidang mekanika. Mekanika merupakan bidang kajian yang berhubungan dengan bergeraknya suatu benda. Seputar hal ini, Newton menemukan beberapa teori sekaligus. Pertama, teori suatu benda yang bergerak karena pengaruh kekuatan luar. Kedua, yang paling terkenal, teori yang menyatakan setiap benda melakukan aksi gerak pasti ada gerak tandingannya (reaksi) dengan besar yang sama tapi arahnya bertentangan. Ketiga, teori gaya berat atau gravitasi, teori ini muncul setelah peristiwa jatuhnya apel, dia menghitung gaya yang dibutuhkan untuk menjaga agar bulan tetap pada orbitnya yang dibandingkan dengaqn gaya yang menarik sebuah benda ke tanah.

·         Matematika
Newton memberikan kontribusi terhadap semua ilmu matematik, dia berhasil menemukan solusi mengenai geometri analitik yaitu diferensial dan integral..

·         produced the universal theory of gravity

• changed ideas about space
• developed the laws of motion
• developed whole areas of mathematics including calculus
• disagreed violently with the deeply held religious beliefs of the day - in particular he did not believe in the Holy Trinity
• was an enthusiastic alchemist who - amongst many other feats - tasted almost all of the known heavy metals (which we now know are poisonous!)
• reformed the Royal Mint

According to the well-known story, it was on seeing an apple fall in his orchard at some time during 1665 or 1666 that Newton conceived that the same force governed the motion of the Moon and the apple. He calculated the force needed to hold the Moon in its orbit, as compared with the force pulling an object to the ground. He also calculated the centripetal force needed to hold a stone in a sling, and the relation between the length of a pendulum and the time of its swing. These early explorations were not soon exploited by Newton, though he studied astronomy and the problems of planetary motion.
Correspondence with Hooke (1679-1680) redirected Newton to the problem of the path of a body subjected to a centrally directed force that varies as the inverse square of the distance; he determined it to be an ellipse, so informing Edmond Halley in August 1684. Halley's interest led Newton to demonstrate the relationship afresh, to compose a brief tract on mechanics, and finally to write the Principia.
Book I of the Principia states the foundations of the science of mechanics, developing upon them the mathematics of orbital motion round centres of force. Newton identified gravitation as the fundamental force controlling the motions of the celestial bodies. He never found its cause. To contemporaries who found the idea of attractions across empty space unintelligible, he conceded that they might prove to be caused by the impacts of unseen particles.
Book II inaugurates the theory of fluids: Newton solves problems of fluids in movement and of motion through fluids. From the density of air he calculated the speed of sound waves.
Book III shows the law of gravitation at work in the universe: Newton demonstrates it from the revolutions of the six known planets, including the Earth, and their satellites. However, he could never quite perfect the difficult theory of the Moon's motion. Comets were shown to obey the same law; in later editions, Newton added conjectures on the possibility of their return. He calculated the relative masses of heavenly bodies from their gravitational forces, and the oblateness of Earth and Jupiter, already observed. He explained tidal ebb and flow and the precession of the equinoxes from the forces exerted by the Sun and Moon. All this was done by exact computation.
Newton's work in mechanics was accepted at once in Britain, and universally after half a century. Since then it has been ranked among humanity's greatest achievements in abstract thought. It was extended and perfected by others, notably Pierre Simon de Laplace, without changing its basis and it survived into the late 19th century before it began to show signs of failing. See Quantum Theory; Relativity.

In 1664, while still a student, Newton read recent work on optics and light by the English physicists Robert Boyle and Robert Hooke; he also studied both the mathematics and the physics of the French philosopher and scientist René Descartes. He investigated the refraction of light by a glass prism; developing over a few years a series of increasingly elaborate, refined, and exact experiments, Newton discovered measurable, mathematical patterns in the phenomenon of colour. He found white light to be a mixture of infinitely varied coloured rays (manifest in the rainbow and the spectrum), each ray definable by the angle through which it is refracted on entering or leaving a given transparent medium. He correlated this notion with his study of the interference colours of thin films (for example, of oil on water, or soap bubbles), using a simple technique of extreme acuity to measure the thickness of such films. He held that light consisted of streams of minute particles. From his experiments he could infer the magnitudes of the transparent "corpuscles" forming the surfaces of bodies, which, according to their dimensions, so interacted with white light as to reflect, selectively, the different observed colours of those surfaces.

The roots of these unconventional ideas were with Newton by about 1668; when first expressed (tersely and partially) in public in 1672 and 1675, they provoked hostile criticism, mainly because colours were thought to be modified forms of homogeneous white light. Doubts, and Newton's rejoinders, were printed in the learned journals. Notably, the scepticism of Christiaan Huygens and the failure of the French physicist Edmé Mariotte to duplicate Newton's refraction experiments in 1681 set scientists on the Continent against him for a generation. The publication of Opticks, largely written by 1692, was delayed by Newton until the critics were dead. The book was still imperfect: the colours of diffraction defeated Newton. Nevertheless, Opticks established itself, from about 1715, as a model of the interweaving of theory with quantitative experimentation.
III  MATHEMATICS
In mathematics too, early brilliance appeared in Newton's student notes. He may have learnt geometry at school, though he always spoke of himself as self-taught; certainly he advanced through studying the writings of his compatriots William Oughtred and John Wallis, and of Descartes and the Dutch school. Newton made contributions to all branches of mathematics then studied, but is especially famous for his solutions to the contemporary problems in analytical geometry of drawing tangents to curves (differentiation) and defining areas bounded by curves (integration). Not only did Newton discover that these problems were inverse to each other, but he discovered general methods of resolving problems of curvature, embraced in his "method of fluxions" and "inverse method of fluxions", respectively equivalent to Leibniz's later differential and integral calculus. Newton used the term "fluxion" (from Latin meaning "flow") because he imagined a quantity "flowing" from one magnitude to another. Fluxions were expressed algebraically, as Leibniz's differentials were, but Newton made extensive use also (especially in the Principia) of analogous geometrical arguments. Late in life, Newton expressed regret for the algebraic style of recent mathematical progress, preferring the geometrical method of the Classical Greeks, which he regarded as clearer and more rigorous.
Newton's work on pure mathematics was virtually hidden from all but his correspondents until 1704, when he published, with Opticks, a tract on the quadrature of curves (integration) and another on the classification of the cubic curves. His Cambridge lectures, delivered from about 1673 to 1683, were published in 1707.
The Calculus Priority Dispute
Newton had the essence of the methods of fluxions by 1666. The first to become known, privately, to other mathematicians, in 1668, was his method of integration by infinite series. In Paris in 1675 Gottfried Wilhelm Leibniz independently evolved the first ideas of his differential calculus, outlined to Newton in 1677. Newton had already described some of his mathematical discoveries to Leibniz, not including his method of fluxions. In 1684 Leibniz published his first paper on calculus; a small group of mathematicians took up his ideas.
In the 1690s Newton's friends proclaimed the priority of Newton's methods of fluxions. Supporters of Leibniz asserted that he had communicated the differential method to Newton, although Leibniz had claimed no such thing. Newtonians then asserted, rightly, that Leibniz had seen papers of Newton's during a London visit in 1676; in reality, Leibniz had taken no notice of material on fluxions. A violent dispute sprang up, part public, part private, extended by Leibniz to attacks on Newton's theory of gravitation and his ideas about God and creation; it was not ended even by Leibniz's death in 1716. The dispute delayed the reception of Newtonian science on the Continent, and dissuaded British mathematicians from sharing the researches of Continental colleagues for a century.
V  ALCHEMY AND CHEMISTRY
Newton left a mass of manuscripts on the subjects of alchemy and chemistry, then closely related topics. Most of these were extracts from books, bibliographies, dictionaries, and so on, but a few are original. He began intensive experimentation in 1669, continuing till he left Cambridge, seeking to unravel the meaning that he hoped was hidden in alchemical obscurity and mysticism. He sought understanding of the nature and structure of all matter, formed from the "solid, massy, hard, impenetrable, movable particles" that he believed God had created. Most importantly in the "Queries" appended to "Opticks" and in the essay "On the Nature of Acids" (1710), Newton published an incomplete theory of chemical force, concealing his exploration of the alchemists, which became known a century after his death.
VI  HISTORICAL AND CHRONOLOGICAL STUDIES
Newton owned more books on humanistic learning than on mathematics and science; all his life he studied them deeply. His unpublished "classical scholia"—explanatory notes intended for use in a future edition of the Principia—reveal his knowledge of pre-Socratic philosophy; he read the Fathers of the Church even more deeply. Newton sought to reconcile Greek mythology and record with the Bible, considered the prime authority on the early history of mankind. In his work on chronology he undertook to make Jewish and pagan dates compatible, and to fix them absolutely from an astronomical argument about the earliest constellation figures devised by the Greeks. He put the fall of Troy at 904 BC, about 500 years later than other scholars; this was not well received.
VII  RELIGIOUS CONVICTIONS AND PERSONALITY
Newton also wrote on Judaeo-Christian prophecy, whose decipherment was essential, he thought, to the understanding of God. His book on the subject, which was reprinted well into the Victorian Age, represented lifelong study. Its message was that Christianity went astray in the 4th century AD, when the first Council of Nicaea propounded erroneous doctrines of the nature of Christ. The full extent of Newton's unorthodoxy was recognized only in the present century: but although a critic of accepted Trinitarian dogmas and the Council of Nicaea, he possessed a deep religious sense, venerated the Bible and accepted its account of creation. In late editions of his scientific works he expressed a strong sense of God's providential role in nature.
VIII  PUBLICATIONS
Newton published an edition of Geographia generalis by the German geographer Varenius in 1672. His own letters on optics appeared in print from 1672 to 1676. Then he published nothing until the Principia (published in Latin in 1687; revised in 1713 and 1726; and translated into English in 1729). This was followed by Opticks in 1704; a revised edition in Latin appeared in 1706. Posthumously published writings include The Chronology of Ancient Kingdoms Amended (1728), The System of the World (1728), the first draft of Book III of the Principia, and Observations upon the Prophecies of Daniel and the Apocalypse of St John (1733).