Questions tagged [physics]
For questions about the scientific discipline that concerns itself with analysing the laws of nature in full generality
736
questions
3
votes
1
answer
58
views
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 ...
- 2,006
5
votes
6
answers
2k
views
What are some concepts/discoveries in mathematics and science that found practical application years after they had been formulated/discovered?
I'm looking for examples of ideas/discoveries/concepts in Maths or Science that had no practical application at first and were maybe considered as nothing but a theoretical concept but they turned out ...
- 1,799
9
votes
3
answers
3k
views
What is the origin of the $\hbar$ symbol?
Equations involving Planck's constant, $h ,$ are often simplified by instead writing them in terms of the reduced Planck's constant, $\hbar \equiv \frac{h}{2 \pi}.$ But where did the symbol for the ...
- 3,637
2
votes
1
answer
114
views
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.
...
- 141
2
votes
1
answer
115
views
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 ...
- 123
3
votes
1
answer
150
views
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?
- 527
1
vote
0
answers
39
views
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^{\...
- 11
6
votes
2
answers
485
views
Was the sun assumed to be at rest aether frame?
Back in the past, was the sun assumed to be at rest in the luminous aether frame?
- 1,173
18
votes
2
answers
7k
views
What was different about Planck's quantization of light compared to Einstein's?
In describing black body radiation Planck assumed that the energy that can be absorbed or emitted by charges is quantized, i.e., they can only absorb or emit certain quantities of energy. But it was ...
1
vote
0
answers
30
views
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 ...
21
votes
12
answers
5k
views
What are examples of serendipity in the history of the sciences and math?
Cosmic microwave background radiation was discovered after Penzias & Wilson couldn't get rid of the noise generated by their horn. In fact, the noise was their discovery.
The strings in string ...
- 327
4
votes
0
answers
79
views
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 ...
- 275
7
votes
1
answer
260
views
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 ...
- 1,799
0
votes
0
answers
45
views
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 ...
- 135
4
votes
0
answers
116
views
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, ...
- 1,799
2
votes
1
answer
441
views
What is the history of the use of the word daughter for a decay product in nuclear physics?
I was browsing the book Isotopes: Principles and Applications by Faure and Mensing and I would like to know what is the history of the use of the word daughter for a decay product. It seems to me that ...
- 117
3
votes
0
answers
155
views
Upon which incorrect equation of Euler did Sophie Germain rely in her work that won a prix extraordinaire from the Paris Academy of Sciences?
Wikipedia's Sophie Germain; Work in elasticity; Subsequent attempts for the Prize says:
Germain had derived the correct differential equation (a special case of the Kirchhoff–Love equation),31 but ...
2
votes
0
answers
196
views
Where can I find Lagrange’s original equilateral triangular solution for arbitrary masses?
This answer to What kind of triangle is formed by three unequal masses in a circular restricted three body orbit? explains that
In the Newtonian limit, an equilateral 3-body solution exists for any ...
- 2,006
3
votes
2
answers
202
views
Where are the mirrors of historic telescopes today?
Are the great mirrors and lenses of historic telescopes, especially those of Herschel, Rosse and many others back from the 18th and 17th centuries, preserved? The wooden structures of those telescopes,...
0
votes
0
answers
89
views
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 ...
- 1,799
1
vote
0
answers
77
views
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 ...
- 327
0
votes
0
answers
61
views
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 ...
- 101
2
votes
0
answers
123
views
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 ...
- 121
14
votes
6
answers
671
views
Has science fiction ever caused scientists to do real research?
Has science fiction ever caused scientists to do real research?
Science fiction here means fiction that tries to explain things in the world rather than speculate about the future or unexplorable ...
- 1,173
2
votes
1
answer
186
views
How did Gibbs discover Gibbs entropy?
I have read and I think that I agree with the idea that if we have to choose probability distribution for an unknown system then it is a good idea to choose a distribution that has the least bias.
I ...
- 111
3
votes
1
answer
122
views
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 ...
- 45.1k
5
votes
1
answer
288
views
Did old Crookes Radiometers ever have a pair of terminals?
This is a question about old physics lab equipment.
This and this question led to the question in SciFi SE Crookes Radiometer at the end of a telescope in old movie scene, something about a comet? ...
CommunityBot
- 1
1
vote
0
answers
76
views
Historical proofs of the series expression for the Bessel function of the first kind
Introduction
The Bessel function of the first kind $J_n(x)$ ($n \in \mathbb{Z},\ x \in \mathbb{R}$) appeared early among other topics, in Celestial Mechanics, in the series expression of the true ...
- 11
27
votes
2
answers
2k
views
What attracted Einstein to the anomalous precession of Mercury?
The story is usually told starting with Einstein's 1915 paper Explanation of the Perihelion Motion of Mercury from General Relativity Theory, or at least its drafts from 1913-14. It was the first ...
- 256
2
votes
1
answer
108
views
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,...
- 206
3
votes
1
answer
158
views
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 ...
- 525
0
votes
0
answers
38
views
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 ...
- 327
2
votes
1
answer
203
views
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 ...
- 283
1
vote
1
answer
133
views
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 ...
- 283
4
votes
1
answer
98
views
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 ...
- 2,347
12
votes
1
answer
2k
views
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 ...
- 2,006
3
votes
0
answers
100
views
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-...
0
votes
1
answer
86
views
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 ...
- 1,009
9
votes
3
answers
13k
views
Old square bracket notation for units
As discussed in this answer https://physics.stackexchange.com/a/77691/667 there are several common conventions for the notation $[q]$ of a physical quantity $q$.
However, I often see people to put ...
- 161
2
votes
0
answers
79
views
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 ...
- 121
1
vote
1
answer
252
views
The unit Ångström
The website http://ucum.org/ucum.html tells us whether every unit is metric or not. Metric units can be multiplied by a power of 10 and can be combined with a prefix. One ångström is defined as 0.1 ...
1
vote
1
answer
132
views
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 ...
- 1,652
4
votes
1
answer
496
views
Names of the electromagnetic units in SI
The unit of electric charge is the coulomb, named after Charles Augustin de Coulomb. This makes sense because Coulomb's law talks about the force between two charges. Likewise, it also makes sense to ...
3
votes
2
answers
350
views
How did Kirchhoff express his voltage law (KVL)
It is sometimes claimed that Kirchhoff's Voltage Law (KVL) is equivalent to the statement that a given electric field is conservative. Or, put another way, is is sometimes claimed that KVL is ...
0
votes
0
answers
107
views
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 ...
- 1,049
9
votes
3
answers
617
views
In which units did Sir Isaac Newton define force at that time as SI system didn't exist then?
Sir Isaac Newton led the foundation of his famous laws of motion during the 17th Century but at that time SI system hadn't existed. So in which units did he define force? Did he define it in some ...
- 3,510
0
votes
0
answers
43
views
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
...
- 101
8
votes
2
answers
4k
views
Did Maxwell originally write his equations using quaternions?
I read somewhere, some time ago that Maxwell originally wrote his eponymous equations using the formalism of quaternions and it was only the later intervention of Gibbs and Heaviside that put them ...
- 1,049
6
votes
5
answers
734
views
Whatever happened to quaternions?
Quaternions were made up by Hamilton. They are an extension of complex numbers. It is said that he first introduced "3d tertions". He was thinking what the relation between $\bf i$ and $\bf ...
- 1,049
1
vote
1
answer
141
views
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?
- 327