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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Original description of point sources and point spread functions
I already asked this question in the Astronomy community, but there it was recommended to me to also try my luck here.
I would like to know the original description of point sources and point spread ...
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The etymology of "radio waves"
The word "radio" originates from "radius", which in turn came from "ray". That's why "radius" means any line from a central focal point to any directions.
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Were scientific discoveries ever inspired by art?
We can often see art that is influenced by science, be it in paintings, music, novels or movies. But has any idea from the arts ever influenced a scientist to come up with a new discovery or idea?
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How did Aristotle explain the motion of living things moving by themselves, and falling of objects, with his hypothesis of all motion needing a cause?
Aristotle (384 BC – 322 BC), a pioneering, iconoclastic, and brilliant ancient Greek philosopher, made the observation in his books that the long term stable state of objects is at rest, that motion ...
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Poisson's laws for adiabatic processes
I've been reading about Thermodynamics lately. The set of equations satisfied in an adiabatic process (and also more generally in polytropic ones) is:
$$p_1V_1^\gamma = p_2V_2^\gamma$$
$$T_1V_1^{\...
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Understanding how Stern-Gerlach tests Bohr-Sommerfield Hypothesis
I am trying to get to the bottom of a few things in the Stern-Gerlach experiment. First, on wikipedia, it says
The Sommerfeld model predicted that the magnetic moment of an atom measured along an ...
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On Bryce Seligman DeWitt's Name Change
Weinberg, in his memoir on Bryce Seligman DeWitt (available at https://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/dewitt-bryce.pdf) states that
In 1950 two major but totally ...
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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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Resource recommendation for experiments that led to major concepts in physics
Any resource recommendations for history of physics giving special attention to experiments that led to certain concepts and theorems in physics? For example what led to the motivation of definition ...
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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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How futuristic was the use of a laser in 1964's "Goldfinger"?
In the 1964 adaptation of the James Bond novel "Goldfinger", in a famous scene, Bond is bound to a table and threatened to be cut in half by a powerful laser that Goldfinger later uses to ...
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Why was Principia Proposition 43, Theorem 22 not published?
Why was Proposition 43, Theorem 22, of Newton's Principia not printed?
Weinberg, To Explain the World (2015) describes this proposition:
In an unpublished “Proposition 43” that did not make it into ...
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Weyl's gauge theory and railroad tracks
There is a claim I occasionally read that the origin of the word "gauge" refers to a track gauge used in railroad tracks (the distance between two rails). It's a claim I have seen here, here,...
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Density effect of energy loss of fast ions as a test of relativity
I am thinking about the relation between the Nobel physics committee and Einstein’s relativity theories. It was clear in 1922 based on the bizarre inscription on the committee’s handcrafted diploma ...
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Did Einstein believe the laws of physics would be replaced by mathematical identities?
I'm sure this wasn't his intention at the outset, but here's my understanding of the history of GR so you can see where I'm coming from:
The Einstein-Grossmann "Entwurf" version of the ...
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What did Nathan Rosen (from EPR) say about Bell's inequality and its violation?
Motivated by this year's Nobel prize in physics, I was wondering whether there are recorded statements by Nathan Rosen (the R in the EPR-paradox) about the Bell inequality and its violation by this ...
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Why was Alain Aspect discouraged from doing his now Nobel-winning work?
In an interview following Aspect's winning of the Nobel Prize in Physics, he claims that John Stuart Bell discouraged him from pursuing his now-famous 1982 experiment on quantum entanglement. The ...
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What did physics mean in 17th century?
In a latter to Huygens, Leibniz wrote Nam in applicatione Geometriae ad Physicam saepissime contingit, which is traslated by Blåsjö (p. 67) as For in the application of geometry to physics it happens ...
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How Galileo could both possibly say that Earth is revolving around the Sun and develop the Galilean relativity?
I always have been curious about this part of the History of Science. To claim that Earth is orbiting the Sun instead of the opposite is equivalent to change one absolute referential (Earth) to ...
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What are the favorite interpretations of quantum mechanics by the recent Nobel laureates in physics?
The new Nobel laureates in physics have been given the prize because of their contributions to quantum mechanics (QM).
Of course, the Nobel prize focusses more on groundbreaking work that has links to ...
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What's the early history of the "inner quantum number"?
Pais, in his "Inward Bound", describes the early history of spin. He tells us that Goudsmit and Uhlenbeck interpreted Pauli's "doubled valuedness" as spin, while in turn Pauli re-...
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What is the origin of the name "degeneracy" pressure and "degenerate" Fermi gas?
What is the origin of the name "degeneracy" pressure and "degenerate" Fermi gas?
I was trying to find the first paper that used the term "degenerate/degeneracy" to ...
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Were the Euler-Bernoulli beam bending equations used in the design of the Eiffel Tower?
On Wikipedia, I read that the Euler-Bernoulli equations on beam-bending were used in the design of the Eiffel Tower:
It was first enunciated circa 1750, but was not applied on a large scale until the ...
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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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What's the difference between Galileo's "impeto" and "momento"?
In Galileo's Two New Sciences, he describes an experiment demonstrating pendulum motion and how the pendulum will rise to the same height from where it started its fall. This discussion can be found ...
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Why was the concept of momentum invented in the first place, and what is its history?
Why was the concept of momentum invented in the first place, and is it useful in the different discoveries and equations that came after?
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Why was the idea of "field" introduced?
I read in my Physics textbook that the notion of Electric fields are useful "when we have to deal with time dependent Electromagnetic phenomenon since no information can travel faster than light&...
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What is the difference between Newton's definitions and axioms?
What is the difference between definition and axiom? For instance, Newton's Definition 1 reads: (Cohen p. 403)
Quantity of matter is a measure of matter that arises from its density and volume ...
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Did most or just few physicists think in 1900 that there was nothing important left to discover?
For example, the whole microscopic world was unknown - isn't that a fundamental problem even bigger than the "two clouds" to solve? They could regard atoms, electrons and other discovered ...
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Why and when was the kinetic theory of gases generalized to fluids?
I've been reading about kinetic theory of gases, which only deals with gases. I know that the lattice Boltzmann method, which is commonly used to simulate fluid flows, finds its origin in the kinetic ...
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Did Halley, Wren and Hooke use $a=v^2/r$ to infer the inverse square law?
I'm reading Richard Conn Henry's article called "Circular Motion." In it he states that in his De vi Centrifuga Huygens discovered the formula $a=v^2/r$ and that
Edmund Halley, Christopher ...
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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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Parisian scholastics' work on mechanics
I was reading the Compendium of the foundations of classical statistical physics by Jos Uffink where, on p. 4, the following statement is made:
In a discussion of the foundations of classical ...
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Interviews / Conversations with Einstein
I'm searching interviews and/or conversations (in English) with Einstein as text. Is there something available? In particular physics (e.g. theory of relativity) would be interesting but also other (e....
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Component form of the fourth Maxwell's equation
I am doing an introduction to Maxwell's equations, and it is said that originally the equations were in component form. Can anyone help with the derivation of the fourth equation? I have checked many ...
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Did quantum mechanics solve any open problems related to the optical properties of solids?
It is clear that the understanding that matter is made of atoms allows us to refine our calculations and go beyond the usual optics. Quantum mechanics solved many issues like the black body radiation, ...
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Hilbert's criticism on the first version of Einstein's field equations
Crossposted at Physics Stack Exchange
I have read once that Hilbert had some reservations regarding the first form of the field equations
$$ R_{\mu\nu} = k T_{\mu\nu} $$
because it was not possible ...
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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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History of determining the specific charge of the electron by balacing electric and magnetic forces
Nowadays is a well known high school or undergrad lab experiment to determine the specific electron charge by using a Wien-filter setup as described for example here.
Up to now I thought that this ...
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Did John von Neumann make any comments about the Many Worlds Interpretation of Hugh Everett?
I was having a discussion with a physicist about Many Worlds Interpretation and he told me that von Neumann like the idea of having multiple worlds in quantum mechanics. When I asked him about more ...
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Why is $T_{\mu\nu}$ the Standard Notation for the Stress-Energy-Momentum Tensor
My question is simple: why do we use $T_{\mu\nu}$ to denote the stress energy momentum tensor, and when was the concept of the stress energy tensor first (or roughly the first) introduced (and by whom)...
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References for Laplace's question regarding Newtonian Gravity
In this lecture by Prof. Frederic Schuller @ 17:49 , it is said that Laplace asked a question if force could be seen equally as curvature of the underlying space which the particle moves in. However, ...
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How did they explain the radiation from hot objects at different wavelengths before the concept of atom was widely accepted?
I was reading about blackbody radiation and came across the following quote.
Planck did not believe in atoms, nor did he think the second law of
thermodynamics should be statistical because ...
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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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When was the geometric structure of a water molecule discovered?
How and when was water the structure of a water molecule (specifically the angles) discovered?
Was it discovered by using a specific type of spectroscopy?
I know you can derive these angles ...
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Why is thermodynamics called thermodynamics?
Thermodynamics is derived from two Greek words
Therme, which means heat
Dynamis, which means power
We know that 'thermodynamics' encapsulates many concepts like energy, temperature, entropy, exergy, ...
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Help in Understanding Emission theory of Empedocles
Empedocles state that the Eyes have fire in them surrounded by water, by this fire ray of the beam goes from eyes to object, then we see that thing, But Question arises to me, Than why not people able ...
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Did Maxwell discuss charge quantization?
I once read in Wikipedia that James Clerk Maxwell included the possibility that charge could be both quantified and continuous. Since the electron hadn't been discovered in 1873, does Maxwell discuss ...
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In which work was Boltzmann's entropy originally introduced?
I get an impression from this enyclopedia entry
that the primary source of the Boltzmann entropy equation $S = k \log W$ might be
1866, Über die Mechanische Bedeutung des Zweiten Hauptsatzes der ...
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