# Questions tagged [physics]

For questions about the scientific discipline that concerns itself with analysing the laws of nature in full generality

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### What did the Italian Nobel laureate Riccardo Giacconi think about the Multiverse hypothesis?

Riccardo Giacconi (1931-2018) was an Italian astrophysicist who was awarded with the Nobel prize in physics back in 2002 for his important contributions to astrophysics. Since he was an astrophysicist,...
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### Reference for history of physics with description of mathematical models

I am interested in some reference text, for example, textbook that would describe going from old times (say, Greece) till modern times: 1) definitions of units and measurements 2) describing ...
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### What was Newton's view of theory of matter?

Did Newton believe in infinitely small particle theory of matter? Because when he talks about axis of rotation, which is locus of the centers of the circles of the rotating body and particle on the ...
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### Metre definition using a seconds pendulum

I have always heard that the first and most prominent definition of the metre was to use the length of the seconds pendulum - pendulum with the period of exactly 2 seconds. However, in the end it was ...
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### Capacitance or capacity?

In physics, the capacitance of a conductor is (roughly) the net charge accumulated when it is grounded relative to a unit voltage at infinity. The same quantity comes up in mathematics, but we call ...
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### Why isn't the ${\gamma}^5$ matrix called ${\gamma}^4$?

This is not really a physical question, but it relates to notation in QED. The ${\gamma}^5$ matrix is defined as $${\gamma}^5=i{\gamma}^0 {\gamma}^1{\gamma}^2{\gamma}^3$$ Wouldn't it be more ...
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### Why was the question of the nature of light limited to the wave theory or the particle one ?

The question is in the title. I'm obviously refering to the 17/18 th century somewhere around this era.
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### Looking for specific book about renaissance physics

I read a book a while ago about the history of physics in the renaissance, which treated it as an alternation between physical-causal descriptions (eg. inertia obtains because air molecules are pushed ...
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### When was brehmsstrahlung discovered?

I remember that not long ago wikipedia had somewhere info regarding the discovery of that phenomenon, but apparently all reference hasbeen removed. Searching the web I found a serbian site claiming ...
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### Need a reference for Euler's velocity initial condition for the wave equation

In DOI: 10.4236/ahs.2020.94019 235 Advances in Historical Studies, p.234 D’Alembert and the Wave Equation: Its Disputes and Controversies, or https://www.scirp.org/pdf/ahs_2020112716312281.pdf p.6 of ...
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### Did J. W. Gibbs “invent” Hilbert spaces before Hilbert formulated the notion of such spaces?

I was surprised to see a reply to a comment on his answer to a Quora question by a research mathematician claiming that Hilbert spaces were actually due to J. W. Gibbs rather than to D. Hilbert. The ...
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### Early sources for surface and bound charges in polarization

I am looking for early sources (references) to the analysis in electrostatics where the polarization vector is rewritten in terms of bound charges and a surface polarization charge. In terms of what I ...
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### Early triboelectricity

I am looking for good sources to quote for early work on triboelectricity. I already have the standard ones, e.g. Benjamin Park (1898) "A history of electricity..", Roller & Roller (1953)...
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### Did Heisenberg say free will could arise from quantum probabilistic mechanics?

I see this view attributed to him a lot during Twitter debates but I never found the source for it does anyone know if Heisenberg actually held this view/suggested it?
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### Origins of a "Theory of Everything" in physics

In physics, is it possible to trace the history of the idea that the known forces (electromagnetic, weak, strong and gravity) should be unified in a "Theory of Everything"? Would it go back ...
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### Did Einstein attribute a physical meaning to the affine connection in his unification models?

As seen in Einstein's 1920 address from the University of Leiden, for example, he did consider it meaningful to distinguish between the presence and absence of the aether, and certainly he seemed to ...
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### Was there a French nuclear weapons project during WWII?

France research pioneered the discovery of radioactivity and nuclear research. However looking at the names of non-US Americans in the Manhattan project there are very few French names (maybe just ...
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### Reference Request: History of Chern-Simons Theory

Chern-Simons theory is a topological gauge field theory and play a prominent role in many brnaches of phyiscs and mathematics. On the physical side, it appears for example in three-dimensional ...
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### When Was The Leidenfrost Effect First Demonstrated By Touching Molten Metal?

The Leidenfrost Effect is a described as follows on Wikipedia: The Leidenfrost effect is a physical phenomenon in which a liquid, close to a surface that is significantly hotter than the liquid's ...
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### Why is there no special unit there for velocity/speed?

Heat, time, and electrical current have separate units, namely, calorie, second and ampere, respectively. However, there is no special unit for velocity. We still use $\frac{\rm m}{\rm s}$. Why? ...
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### According to Heisenberg, is quantum theory merely a calculation procedure for predictions?

Is quantum theory just a mathematical tool for correct predictions, according to Heisenberg's views? What are his personal ontological commitments in relation to quantum theory (if he had any ...
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### Quote about the history of particle physics

I have a (very) vague remembrance of a quote about the history of particle physics, particularly (I think?) the development of the standard model. As I recall, it was about how it was a very exciting ...
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### What concept did pre-modern people have about thermodynamic phenomena?

How did people before the advent of modern science in the 17th century conceive thermodynamic phenomena? I want to know how people in Ancient Mesopotamia, Egypt, Greece, Rome, China and in the Middle ...
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### On implications of Schrodingers Cat regarding macroscopic quantum states and decoherence

How exactly did Schrodingers Cat lead to development regarding macroscopic quantum states and decoherence? One often hears that the thought experiment was the initiator to the question, whether ...
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### How did the US get enough U235 for "Little Boy"

The answer to a different question (Where did Fermi get the U235 for the first nuclear pile) about U235, was that Fermi used natural uranium for his reactor. This explains, in particular, the origin ...
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### How was it determined that charge and current were made of the same stuff?

Even in my earliest physics course we took for granted that charges are made of electrons (or their absence) and currents are due to the motion of electrons. But the electron is a very modern concept ...
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In magnetism, there are two different magnetic fields, that I will simply call $\mathbf B$ and $\mathbf H$. The distinction is not always clear. In experiments $\mathbf H$ is the applied field while $\... • 2,698 0 votes 0 answers 49 views ### Which scientist(s) first measured the elementary charge and how did they do it? [duplicate] I would be grateful if anyone could shed some light on these questions. Which scientist(s) first measured the elementary charge? If it wasn't measured in a straightforward experimental setting, and ... 0 votes 1 answer 165 views ### What is the difference between caloric and heat? What is the difference between caloric and heat? Is there a difference? 0 votes 0 answers 49 views ### Did proponents of classical and statistical thermodynamics get along well with each other? Proponents of classical thermodynamics believed the subject matter to be continuous, while the statistical thermodynamics proponents' subject matter was made up of atoms and variations of collectives ... 0 votes 0 answers 191 views ### Galileo's discovery of the independence of motion It is well-known that Galileo was the first one to state that motions in different dimensions (or components) are independent of one another. Where is this in Galileo's writings? • 1 0 votes 0 answers 120 views ### Soviet atomic bomb development — advantage of knowing it could be done, was this ever said by any Soviet scientist? I have heard it said that even if Fuchs had not provided details which must have been invaluable — just knowing, for example, that implosion and explosive lenses were employed without any further ... • 1,111 0 votes 0 answers 134 views ### How did Gauss, Ampere and Biot-Savart derive their laws? Gauss' law for electricity and magnetism, Ampere's law and Biot-Savart's law — all of these laws are crucial for understanding electromagnetism and Maxwell's equations. But I want to know how each of ... 0 votes 0 answers 233 views ### How is it possible that Pierre and Marie Curie's daughter Ève was so healthy? I know that problems caused by radiation are pretty much random and unexpected at low levels of exposition but this randomness begins to be more probable when the exposition grows and this makes me ... • 109 0 votes 0 answers 32 views ### In which year the notion of star death started? In which year, does the fact: every star will ultimately die came in to existence? • 353 0 votes 0 answers 126 views ### Gravity's Rainbow: An accidental nominal similarity in science and literature? There is an interesting extension of Einstein's Special Relativity, known as Doubly Special Relativity (presented after 2002) in which there is not only an observer-independent maximum velocity (i.e., ... 0 votes 0 answers 399 views ### Famous gypsy/romani physicists? Are there any famous/notorious Romani physicist? Thanks! 0 votes 0 answers 190 views ### Was Landau interested in the interpretations of quantum mechanics? I am interested in Lev Landau. I was trying to find what was his approach to the interpretation of quantum mechanics, I am unable to find any particular source were this is discussed. Was he an ... • 2,698 0 votes 0 answers 75 views ### Do we know how Feynmans religious views changed throughout his life? According to Feynman, there was a quota for Jews at American Universities and when he was accepted on a graduate programme - I think at Princeton - they were told "he's Jewish but he doesn't act ... • 3,613 0 votes 0 answers 452 views ### When were the SUVAT equations derived for the first time? It's one of the first things learned in Physics. However, what's the history behind deriving the SUVAT equations? And, there were other equivalent equations used before SUVAT came into the curriculum? • 291 0 votes 0 answers 717 views ### kinetic energy formula written as mv^2 I stumbled across the following quote and couldn't understand how one wouldn't use the factor of 1/2 without completely disrupting the work-energy principle. Though, informal, energy is defined as the ... • 377 0 votes 0 answers 75 views ### Some questions about radioactivity around 1900 All the questions are closely related to each other therefore, in my opinion, it wouldn't make much sense to ask them separately. I'm trying to find the answers in historical context. I appreciate ... • 377 0 votes 0 answers 84 views ### Was Lagrange the first to have used generalized coordinates? I was wondering if Lagrange was the first to use generalized coordinates as defined by their wikipedia article. • 1,516 0 votes 0 answers 62 views ### Did the mathematician Garrett Birkhoff ever work with or mention Feynman's path integrals? Did Garrett Birkhoff ever work with Feynman's path integral? Did he ever work in his Many-Histories interpretation? Or at least, did he mention it in any of his articles? • 297 0 votes 0 answers 41 views ### Did pre-Galilean astronomy inspire Mach's principle? Was Mach, in his formulation of "Mach's principle," influenced by pre-Galilean astronomy, such as that of Aristotle in On the Heavens, where heavenly bodies influence terrestrial ones? • 5,239 0 votes 0 answers 111 views ### Dirac and proton-electron annihilation Wikipedia says: Robert Oppenheimer argued strongly against the proton being the negative-energy electron solution to Dirac's equation. He asserted that if it were, the hydrogen atom would rapidly ... 0 votes 0 answers 279 views ### What did Hans Bethe think of von Neumann's quantum logic? Nobel laureate Hans Bethe was a friend of mathematician-physicist John von Neumann, and he once said: "I have sometimes wondered whether a brain like von Neumann's does not indicate a species ... 0 votes 0 answers 81 views ### Theory criteria from Misner-Thorne-Wheeler In chapter 39.1 of Gravitation, by Misner, Thorne and Wheeler, it is asserted, quite reasonably, that a theory of gravitation (and, I assume, quite generally) must satisfy the three following criteria ... • 773 0 votes 0 answers 163 views ### Does Einstein's original derivation of$E=mc^2\$ exist and what is it?

I read an article published by Scientific American stating that Einstein did not prove the equation within the context of Special Relativity but I am skeptical. I was hoping someone could point me in ...
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