#physics

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English polymath Isaac Newton was born in 1642.

Newton's book Philosophiæ Naturalis Principia Mathematica, first published in 1687, achieved the first great unification in physics and established classical mechanics. Newton also made seminal contributions to optics, and shares credit with German mathematician Gottfried Wilhelm Leibniz for formulating infinitesimal calculus, though he developed calculus years before Leibniz.

https://www.gutenberg.org/ebooks/author/6288

Portrait of Isaac Newton (1642-1727). Newton is shown in a formal seated or standing pose, befitting his status as a scientist, mathematician, and member of the gentry. He is dressed in the fashion of a gentleman of his time, often wearing a long, dark robe or coat, sometimes over a waistcoat and cravat. Newton’s features are typically portrayed with precision: A high forehead and prominent nose, symbolizing intelligence and authority. Deep-set, thoughtful eyes, suggesting a reflective and intellectual demeanor. His white or gray wig, a common accessory for men of his era, frames his face, adding a sense of dignity.

replied to Project Gutenberg's status

"As I have pointed out already in my general exposition of the constitution of line spectra, and have afterwards tried further to confirm, there can be no doubt that these series are really parts of a single group of lines with two variable integral parameters, the general formula of which can be written approximately."

Lines in the Hydrogen Spectrum (1897)

~Johannes Rydberg (8 November 1854 – 28 December 1919)

What Is Entropy? A Measure of Just How Little We Really Know.

Exactly 200 years ago, a French engineer introduced an idea that would quantify the universe’s inexorable slide into decay. But entropy, as it’s currently understood, is less a fact about the world than a reflection of our growing ignorance. Embracing that truth is leading to a rethink of everything from rational decision-making to the limits of machines.

By Zack Savistky

https://www.quantamagazine.org/what-is-entropy-a-measure-of-just-how-little-we-really-know-20241213/

Carnot aged 17 in the uniform of a cadet of the École polytechnique. Portrait by Louis-Léopold Boilly (1813).

replied to Project Gutenberg's status

"The difficulties which would have to be overcome to make several of the preceding experiments conclusive are so great as to be almost insurmountable."

Warning about the non-conclusiveness for the experimental foundation of electrostatic theory, in a footnote of the third edition of: James Clerk Maxwell (1891). A Treatise on Electricity and Magnetism, Vol.1, 3rd Edition.

~J. J. Thomson (18 December 1856 – 30 August 1940)

J. J. Thomson, who was born in 1856, received the Nobel Prize in Physics in 1906 for his discovery of the electron, the first subatomic particle to be found.

Thomson was also a teacher, and seven of his students went on to win Nobel Prizes: Ernest Rutherford, Lawrence Bragg, Charles Barkla, Francis Aston, Charles Thomson Rees Wilson, Owen Richardson and Edward Victor Appleton.

https://en.wikipedia.org/wiki/J._J._Thomson

Books by J.J. Thomson at PG:
https://www.gutenberg.org/ebooks/author/38322

J.J. Thomson, Nobel Prize photograph (1906). Nobel foundation - http://nobelprize.org/nobel_prizes/physics/laureates/1906/thomson-bio.html Joseph John Thomson (1856–1940), often referred to as J.J. Thomson, is shown in a candid pose, engrossed in writing or drawing, likely related to his scientific work. He is depicted as a middle-aged man with receding hair, a neatly groomed mustache, and a composed, intellectual demeanor. Thomson is wearing formal attire typical of the early 20th century: A dark tweed suit jacket with a subtle texture. A high-collared white shirt and a decorative tie or cravat. A pocket square neatly tucked into his breast pocket, adding to the formal appearance. He is wearing round spectacles, which were characteristic of the period and contributed to his scholarly appearance.

"Science cannot solve the ultimate mystery of nature. And that is because, in the last analysis, we ourselves are part of nature and therefore part of the mystery that we are trying to solve."
Where is Science Going? The Universe in the light of modern physics.

in 1900.

Max Planck presents a theoretical derivation of his black-body radiation law (quantum theory) at the Physic Society in Berlin.

https://en.wikipedia.org/wiki/Planck%27s_law

Max Planck at PG:
https://www.gutenberg.org/ebooks/author/35343

Black body spectral radiance curves for various temperatures after Planck, and comparison with the classical theory of Rayleigh-Jeans (in cgs units). Planck's law accurately describes black-body radiation. Shown here are a family of curves for different temperatures. The classical (black) curve diverges from observed intensity at high frequencies (short wavelengths).

in 1822.

French physicist Augustin-Jean Fresnel, in a memoir read to the Academy of Sciences, coins the terms linear polarization, circular polarization, and elliptical polarization, and reports a direct refraction experiment verifying his theory that optical rotation is a form of birefringence.

https://en.wikipedia.org/wiki/Augustin-Jean_Fresnel

https://en.wikipedia.org/wiki/Polarization_(waves)

The wave theory of light is available at @internetarchive
https://archive.org/details/wavetheoryofligh00crewrich

The wave theory of light; memoirs of Huygens, Young and Fresnel by Crew, Henry, 1859-; Huygens, Christiaan, 1629-1695; Young, Thomas, 1773-1829; Fresnel, Augustin Jean, 1788-1827; Arago, F. (François), 1786-1853 https://archive.org/details/wavetheoryofligh00crewrich