Questions tagged [physics]

For questions about the scientific discipline that concerns itself with analyzing the laws of nature in full generality. It is one of the largest branches of natural science. Before applying this tag to a question, please consider using the "theoretical-physics" or "experimental-physics" tags instead, as they are more descriptive.

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5
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2answers
71 views

What is the history behind defining temperature as measure of hotness?

I know that when two bodies of different temperature are kept in contact "heat" flows from hotter body to colder. But how did anyone know that it is the "hotness" that flows, one could have said that ...
2
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1answer
48 views

When was spin of subatomic particles other than the electron discovered?

The idea of a spin angular momentum was first proposed in a 1925 publication by George Uhlenbeck and Samuel Goudsmit to explain hyperfine splitting in atomic spectra. At what time was it measured ...
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1answer
80 views

Einstein praising Sophus Lie

p. 153 of Raúl M. Falcón Ganfornina and Juan Núñez Valdés, “Mathematical Foundations of Santilli Isotopies,” trans. Alan Aversa, Algebras, Groups, and Geometries 32 (2015): 135–308. quotes (but does ...
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0answers
63 views

How does the concept of centre of mass came to existence?

I am wondering as how does the concept of centre of mass came into being. Considering the usefulness of the concept how were the physicist able to define such a quantity. I mean was it just trial and ...
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0answers
53 views

How did the terms stress and strain come to describe two different things?

In physics, stress essentially captures forces in a body, where as strain captures displacements. Two dimensionally very different concepts. If you look it up in a thesaurus, stress and strain are ...
3
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1answer
165 views

What is the origin of the concept of reduced mass?

I am looking for the origin of the concept of reduced mass as used in vibrational spectroscopy e.g. vibration of a diatomic molecule. Most of the texts simply define reduced mass as the sum of the ...
4
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3answers
170 views

Did anyone mention the possibility of antimatter before 1928?

In 1932 positron and annihilation were discovered, but in 1928 Dirac had provided a formula allowing for the positron Did anyone between that date and the discovery of electron ever imagine or ...
2
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1answer
50 views

What is Leroy Grumman Medal won by theoretical physicist Kenneth G. Wilson?

I happened to find that one of the most important inventors of the renormalization group, Kenneth G. Wilson, won the Leroy Randle Grumman Award Medal in 1986, 4 years after his Nobel prize. Details in ...
3
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1answer
123 views

How did $SU(2)$ came into physics?

It is natural for physicists to consider the group $SO(3)$. Presumably, $SU(2)$ came into physics because of quantum mechanics. How did people realize that when studying rotation of a physical system, ...
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1answer
101 views

What is the ancient cosmic canon of proportion and its role in the history of science?

Who had direct inside knowledge of the canon through the alleged secret oral tradition? Some possible examples that have been alluded to include Pythagoras, Plato, Euclid, Copernicus, Galileo, Kepler, ...
2
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1answer
76 views

How was (non-instantaneous) electric current first discovered?

How was (non-instantaneous) electric current first discovered and what were some of the main first thoughts on it?
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0answers
129 views

What happened to the undergrad students who attended the Feynman Lecture Series in 1961-63?

Note: This question was originally asked here, but I was wondering if I could get further clarification as this has truly intrigued me. In the academic years of 1962-2 and 1962-3, Richard Feynman ...
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1answer
1k views

Why do many names of technical and scientific subjects end with “ics”?

The names of many technical and scientific subjects, like mathematics, physics, statistics, etc., etc., end with letters "ics". What is meant by this, if anything? Was there any logic behind it or is ...
5
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1answer
81 views

When did the use of Sine and Cosine as functions become mainstream?

In the work of early physicists like Newton, everything is explained in terms of cumbersome (in today's standards) geometry. They don't talk about "cosines" of certain angle, but about proportions ...
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1answer
80 views

Are these Newton's quotes apocryphal?

I have stumbled upon the following alleged Newton's quotes, but I could not find them in any of their works. No great discovery was ever made without a bold guess. No sciences are better ...
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2answers
2k views

Who discovered the covering homomorphism between SU(2) and SO(3)?

Who discovered this? It is quite nontrivial and very important in quantum mechanics.
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140 views

Identification of scientists in de Gennes book

Petit Point: A Candid Portrait on the Aberrations of Science is a charming book written by the French physicist Pierre-Gilles de Gennes containing short essays on some of the prominent scientists that ...
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67 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 ...
5
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3answers
418 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 ...
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71 views

Does Einstein's original derivation of E=MC^2 exist and what is it?

I read an article published by Scientific American stating Einstein did not prove the equation within the context of Special Relativity but I am skeptical. I was hoping someone could point me in the ...
5
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1answer
294 views

Why are 'speed' and 'velocity' not given the same name?

Position is a vector. Distance/length is a name of its magnitude. Velocity is a vector. Speed is a name of its magnitude. Acceleration is a name of a vector and its magnitude. Force is a name of a ...
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0answers
98 views

Did Paul Dirac believe in multiple universes?

Prominent physicist Paul Dirac proposed a hypothesis that said that constants and laws of physics would evolve with time into different constants and laws of nature. This hypothesis was used by ...
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0answers
94 views

Feynman's statement about the importance of basic science

I remember reading in the line that Feynman saying if the best technicians were tasked to build a radio they would make longer and thicker cables and transfer message but it took a physicist to ...
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0answers
34 views

Did Werner Heisenberg ever agree or propose the existence of some kind of multiverse?

I was watching a video (https://www.youtube.com/watch?v=muJYTeQlvC4) where the director of a videogame company speaks about one of its most successful games. This game is set in a floating city which ...
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4answers
307 views

Where did the false “equal transit-time” explanation of lift originate from?

It's supposedly a "widely circulated" false claim that wings generate lift because of their asymmetric shape, forcing air above to travel faster so that they meet up on the trailing edge at the same ...
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1answer
75 views

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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0answers
85 views

What did people mean by the term Force in earlier times?

Initially I used to believe that before Newton gave his Laws of Motion, people thought that Force was something that caused motion. It was Newton who first said that Force is something that causes ...
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0answers
57 views

Did Wheeler ever propose the existence of a multiverse containing parallel simultaneous universes?

It is known that the physicist John Archibald Wheeler proposed the existence of a multiverse in the form of a set of cycles of Big Bangs and Big Crunches (Cyclic/Oscillatory Multiverse Model). But I ...
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1answer
104 views

Did physicist David Bohm ever propose the existence of a multiverse?

Did physicist David Bohm ever propose the existence of any kind of multiverse?
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3answers
90 views

Does Heliocentrism predate Copernicus?

I have seen this mentioned on the interwebs a few times. people have mentioned that some Greek thinkers and Islamic astronomers came up with heliocentrism before Copernicus and that Copernicus copied ...
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0answers
49 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 ...
2
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1answer
103 views

What was this experiment tainted by the observer effect?

I once heard a cautionary tale about the dangers of the observer-expectancy effect. It was at least presented as a true example from the history of science, but I'm having trouble identifying the ...
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0answers
116 views

Who discovered Maxwell-Faraday equation, $\nabla\times E=-\frac{\partial B}{\partial t}$? Was it Maxwell or Neumann?

I have been trying to find out who discovered Maxwell-Faraday equation, $\nabla\times E=-\frac{\partial B}{\partial t}$. Was it Maxwell himself, or was it Franz Ernst Neumann who derived it? The ...
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42 views

Did Ludwig Boltzmann ever go to Copenhagen or any other part of Denmark?

Did Ludwig Boltzmann ever go to Copenhagen or any other part of Denmark? I also read that he was appointed "Honorary Doctor" by the university of Oslo. Does this mean that he went to Norway? https://...
2
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1answer
91 views

Are Wheeler's It from Bit/Participatory Universe and the Multiverse related?

Could I ask you for the relation between Wheeler's ideas and the multiverse? Do you know if these are related? I ask you this because I found this very interesting article written by Kip Thorne with ...
6
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1answer
212 views

When and how did the notion/idea of physical constant emerge?

Physical constants (e.g. c, h, G, alpha and so on) play a central role in our scientific theories and they have yet drawn much of controversial flavor into questions concerning the foundational status ...
5
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1answer
233 views

How were negative numbers first used in physics?

The use of negative numbers in most of today's calculations is natural. But how did the use of negative numbers began in physics? What physical quantity required the introduction of negative numbers ...
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1answer
90 views

Did John von Neumann ever go to any Nordic Country? Did Eugene Paul Wigner ever go to any other Nordic Country apart from Sweden?

I'm researching about the presence of important scientists in Nordic Countries (Iceland, Norway, Denmark, Sweden and Finland). I was hoping that someone could help me since I've not been able to find ...
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2answers
2k views

Which physicist is this quote attributed to?

There is a quote from a 19-20th century scientist that goes (and I am paraphrasing): New scientific theories are never accepted until old scientist die. Who is this cynical quote attributed to, ...
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2answers
126 views

What are the great works of Richard Phillips Feynman? [closed]

What are the prerequisites to read his book? Why Richard Phillips Feynman is so famous? What are great works of Richard Phillips Feynman?
5
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2answers
155 views

How did Henry Cavendish deduce the inverse square law in electrostatics from his experiment in 1772?

An elegant experiment in 1772 by Henry Cavendish. Cavendish charged a spherical conducting shell that contained within it, and temporarily connected to it, a smaller sphere. The outer shell was then ...
3
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2answers
166 views

What animals or plants were used to illustrate ideas of physics?

This crossed my mind today... There is Schrödinger's cat and Newton's apple. Are there any other famous animals/plants featured in physics in a similar way?
2
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1answer
71 views

What was Isaac Newton's contribution to optics?

What was Isaac Newton's contribution to optics? I know that he believed in the corpuscular theory of light. Did he know about the laws of reflection ad refraction?
5
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1answer
121 views

Refraction in Newton's Corpuscular Theory of Light [duplicate]

Newton's theory of light stated that a light travelled in a straight line as small particles. When these particles travelled in a medium, they experienced an attractive force with the particles of the ...
2
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0answers
87 views

Were notable physicists great at math or computing? [closed]

Were famous or popular physicists like Galileo, Newton, Einstein, Feynman predominantly mathematicians or scientists (computing, experimenting, engineering, etc.)? I am curious if people like the ...
3
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1answer
142 views

How did philosophers and scientists in the 18th century view mathematical explanation?

The 18th century saw a rise in the use of mathematical formalisms to account for natural phenomena. Works of Lagrange, Euler, d'Alembert, etc., were groundbreaking in the history of mechanics and ...
5
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1answer
108 views

Equivalence principle before Einstein [duplicate]

In a German interview some physicists were asked, what they would ask Einstein, if he were alive today. One of them wanted to know how Einstein came up with the idea of the equivalence principle, that ...
7
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2answers
222 views

Was there early opposition to Newton's mechanics?

Scientific theories are rarely accepted immediately. Even if the evidence for a theory is impeccable, there will be some stragglers who resist it for lack of understanding. More interesting is when a ...
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0answers
41 views

Does anyone know articles or books about what the notion of difficulty in science, especially physics?

In physics, many problems were known at their time to be very challenging, for example the notion of heat, or how to understand the ideal gaz law, or the phase transition criticial behaviors, etc. And ...
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1answer
132 views

Is Newton going to be the new Aristotle? [closed]

As general relativity and quantum mechanics become more accessible, is Newton going to become the new Aristotle, as the example of being wrong and misleading humanity for centuries? (as opposed to the ...