Analogy Definition and 150 Threads

I read a paper published in General Relativity and Gravitation: On gravity as a medium property in Maxwell equations The argument of this paper is as follows in a nutshell: There are currently many analog models and theories of gravity, including some based on medium analogy. Analog...

So, the formula for Gravitational force is F= Gm1m2/r^2 So a given mass such as the earth and a mass such as much self both contribute to an equal and opposite gravitational force on each other. But we can also think of it separately in terms of just the gravitional field generated. The Earth...

An "analogy question": Polynomials with one variable and coefficients in the field K are to finite dimensional K vector spaces as polynomials in several variables over the field K are to ....? As a teenager, I recall taking tests that had "analogy questions" on them. The format was: Thing A...

Is there a gravitational analog of electromagnetic force? [Apart from the obvious "static" forces, ie electrostatic between fixed charges and gravitational between fixed masses.] I am thinking of the classic situation of a moving charge (or current) creating a magnetic field which then...

So, is water for water waves, what is the vacuum for EM waves traveling in vacuum. I know the analogy can't be exactly perfect because water molecules oscillate in the presence of water waves, but in vacuum nothing seems to oscillate? Or the vacuum oscillates in some way? And no I am not trying...

I have read about several approcahes to bypass some classical restrictions to quantum facts such as the electron being in a torus-like shape to avoid ,the greater than speed of light, rotation paradox . Could you recommend websites , sources or books that give good classical analogy to quantum...

Recently I have seen a number of General Relativity visualisations that show spacetime flowing towards any mass, similar to water flowing into a sink hole. ScienceClic's video is an example. That model is also used in the "waterfall model" to explain the event horizon of a black hole, as the...

It is well known that one can solve incident an reflective wave in homogeneous linear media by matching PDE boundary conditions. In the electrical engineering community, one solves similar problem using smith chart and scattering parameters for 1-dimensional propapation of TEM modes in...

There is something unusual about water. Without atmosphere, water can't exist. It's as if water is part of atmosphere. In vacuum, liquid water can't exist. What other things like water where it needs other aspects like atmosphere to exist? And what is the analogy of water in particle physics...

In a zinc / copper danielle cell could we say that the Zinc electrode is like a glass of water (water molecules are electrons) The full glass of water reprenst the charge of the zinc electrode and when you try to fill it with more water it overflows (electrons leave the zinc electrode)

Thank you to the very helpful forum leaders for their aide in comprehending entangled particle detection last week. With regards to superposition, would an analogy be: (which involves a thought experiment): a ceiling fan, at rest, has four distinct blades with four known positions...

{Moderators note: thread split from https://www.physicsforums.com/threads/a-geometrical-view-of-time-dilation-and-the-twin-paradox-comments.842793 } I am a novice about relativity, but I found this convoluted and very difficult to follow. I think the lengths in the different coordinate systems...

How can it be easily shown that it's a bad idea to develop relativistic gravitational theory in full analogy with electromagnetism? I.e. why not to introduce 4-potential for gravitation in analogy with 4-potential in covariant form of Maxwell equations and get something fully analogous to...

Homework Statement Hi everyone, I'm a high school teacher and every time I teach the concept of polarization, students ask me the same question and I can't answer it. I show students this picture. The red lines show the electric field vibrations. After passing through polarizer 1, the...

When the eletctric field was defined I could totally relate to E is like g in mechanics. But for the electric potential I don't know. What would be equivalent analogy?

This has been a real famous analogy and I understand it, except the fact that the balloon surface is a 2D structure. How is it possible to depict a 3D universe on a 2D plane ? What happens when we work with stars at multiple planes ?

Does a circular function with complex variable represent a three-dimensional graph? For example cosiz

I'm working on semiconductor physics and cyclotrons. There's an article that I am trying to understand, but am having difficulties matching with experiment. I asked a question on an electronics site, but apparently the physics is too advanced. The relativity article which sparked my interest...

I have some experience with non-linear least squares curve fitting. For instance, if I want to fit a Gaussian curve to a set of data, I would use a non-linear least squares technique. A "model" matrix is implemented and combined with the observed data. The solution is found by applying well...

Hi. Inductance and capacitance have many analogies, both conceptually and formally. A capacitor connected to a voltage source carries the charge ##Q=C\cdot V##. The analogous equation for inductance is ##n\cdot \Phi=L\cdot I##. Charge is physical, it's proportional to the number of excess...

Hi everyone I would love to get some feedback on this silly idea I had when thinking of the balloon analogy. Another way to achieve the same effect - at least in 2 dimensions - is to move a projector further away from a screen - everything expands relatively. If the universe is a 2d hologram...

Hello everyone, From what i know electrical resistance for metals is a constant, but in fact it varies with temperature but not voltage. Explanation for metals and temperature is something like "heat, which is in fact average speed of electrons, does obstruct tranmission of other electrons...

Can anyone here settle(or contribute to ) a question that is ongoing at another forum? Who came up with the idea of the rubber sheet analogy in Relativity? Some there have wondered if it was the "rubber sheet geometry" as topology was described as ,apparently that may have ,perhaps...

In gauge theories, the counterterms in the equation to balance the gauge freedom (like the phase in electrodynamics) produce the forces of nature. In GR.. what is the equivalent of the counterterms and what is the equivalent of the phase or isospins freedom in electroweak)?

I want to ask this in the Relativity forum but thought there are more quantum experts here. So most of you Bhobba, Neumeier, etc believe the world is really classical and all the quantum things are just for calculation purposes or aids. Can you take the analogy to General Relativity? Can we say...

http://arxiv.org/abs/1202.2115 I know Arxiv isn't a real journal, but this caught my eye. Is this a meaningful physical interpretation of the Riemann hypothesis? From what I understand, the zeta function can be modeled as a wave, but attempting to solve for the real part requires infinite...

I'm referring to the stuff in here: https://en.wikipedia.org/wiki/Gravitoelectromagnetism Is it a good analogy to conceptualize for beginners who have just started GR?

If one can't ever know all the three components of (QM) angular momentum, then can it even be considered as a "vector"? Is it only cause it transforms as a vector in a coordinate transformation?

On his book of the elegant universe when he was explaining the warping of spacetime he use an analogy of a toy called tornado. Basically a spinning machine like a merry go round. Anyway he said, let's give one ruler to the slim who is at the wall of the tornado,to measure the circumference...

This is a kind of cooperative problem solving post. But don't be too terribly 'focused' because likely I have missed important issues. I had not seen a dynamic illustration like this before: maybe I am over impressed, weak-kneed, like seeing Kate Hudson the first time?? In Wikipedia at...

I've been thinking about the balloon surface analogy and I want to ask some questions. Perhaps I am pushing it too far. But in that case it seems important to find its limits. My understanding is that the this analogy is used to illustrate the expansion of the universe and in particular how it...

I don't really feel that I understand what it means for two matrices to be similar. Of course, I understand the need to understand ideas on their own terms, and that in math analogies are very much frowned upon. In asking if you know of any "reasonable" analogies for what it means for two...

phinds submitted a new PF Insights post The Balloon Analogy ... the Good, the Bad, and the Ugly Continue reading the Original PF Insights Post.

Problem: In analogy to the Bohr Theory of the hydrogen atom, develop a quantum theory of Earth satellites, obtaining expressions for the orbit radius (r) and the energy (E) in terms of the quantum number (n) and the other relevant parameters. A satellite of mass 1000 kg is in a circular orbit of...

i was thinking about the Higgs Boson analogy that was put forward to help describe how it works/interacts to produce mass, of a very famous person walking into a party, everyone gathers round impedes progress, high interaction with Higgs field and particles therefore high mass, and then a less...

Homework Statement "Sometimes the idea of the quantum is compared to the units we use for money. A dollar can be divided into smaller units, where the cent is the smallest possible unit. How is this analogy incorrect? Homework Equations E=nhf The Attempt at a Solution My thought is that...

Can anyone give other examples where the geometry is the classical limit of another theory? I can give one. For example. The body curves of a woman is geometric.. so the geometry is the result of the bones and internal structure of the physical body. Likewise, in General Relativity, could the...

I have heard many physicists in the media attempt to describe the Higgs boson in terms of analogies. Many seem to my amateur physicist mind to fall down immediately. One such analogy is that particles with mass interact with the Higgs field as if swimming through treacle. This is particularly...

Thought of this while driving home from the lofters. As if we need one more analogy for relativistic speed limits, but here goes... Q: How is c a speed limit? Why can't we just go a little faster and exceed it? A: Behold an analogy as to how geometry can limit movement, no matter how fast you...

Sorry to bother you all with another-of-its-kind (most probably unsatisfactory) analogy that I came up with myself (error detection sirens should be blaring now) to better understand "energy" in cosmological expansion, but I just can't rest until I find out how (in)accurate it is from you all. I...

For a lay person such as myself, it's very easy to get confused and stumble around a bit, trying to understand how galaxies can be receding greater than the speed of light when the speed of light is the cosmological speed limit. It's easy to make the mistake of saying 'Ha! There are whole...

I have a question on GR. To what extent is the rubber sheet analogy correct? To be more specific, in that analogy, an object with mass M bends the 2-D space (the sheet) into a third dimension (the sheet goes downward). Does this imply that in out universe, an object with mass bends the spacetime...

The trampoline analogy tries to explain gravity in terms of space time curvature the orbit of objects around a massive object can be understood, but what about centre of gravity of the massive object, the images of trampoline is generally shown as seen from top where the massive object is making...

People often use the expanding balloon with galaxies on the surface to represent the expansion of space. But this view doesn't show how this expansion works in 3d and it doesn't show how gravity comes into play. Instead of putting the galaxies on the surface of the balloon all we have to do is...

Hello, I was learning about Avogadro's Law and trying to find some real-life example of it. It mainly states that: For a given mass of an ideal gas, the volume and amount (moles) of the gas are directly proportional if the temperature and pressure are constant. So let's say I have a balloon...

While browsing this festive morning I came across Peter Woit's "(his Oct. 3rd 2011 'Not Even Wrong') statements that: "the fundamental problem of the interpretation of quantum mechanics (is): why don't we see superpositions " and that: "the confusing question is ...how classical behaviour...

There it is. I'll congratulate the solver upon discovering the solution. Hint: the answer is not a one-, two-, three-, or four-letter solution. Good luck.

Hello, I just began learning mass transfer, and I am trying to use analogies from heat transfer to help me solve problems. For example, if you have one dimensional heat transfer through a plane wall, I would start with a general energy balance. $$\frac {dE}{dt} = \dot Q_{x} - \dot Q_{x + \Delta...

What is Raynolds Analogy and its use/application in convection heat transfer coefficient?

Has anyone here ever asked these questions about the balloon analogy? 1. If the universe actually was the 3D surface volume of an expanding 4D hypersphere, how big would the radius be? (let the radius of the observable universe be 46.25 billion light years) 2. How fast is it expanding...