Aether (or ether) relates to the material which supposedly fills the entire universe. It is a concept used to understand action at a distance. Aether was described by Huygens as an "omnipresent, perfectly elastic medium having zero density", to support his wave theory of light.
Questions tagged [aether]
179 questions
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What does a Galilean transformation of Maxwell's equations look like?
In the 1860's Maxwell formulated what are now called Maxwell's equation, and he found that they lead to a remarkable conclusion: the existence of electromagnetic waves that propagate at a speed $c$, which turns out to be the speed of light, implying…
Keshav Srinivasan
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Isn't D'Alembert's wave equation enough to see that Galilean transformations are wrong?
The D'Alembert equation for mechanical waves was written in 1750:
$$\frac{\partial^2u}{\partial x^2}=\dfrac{1}{v^2}\dfrac{\partial^2u}{\partial t^2}$$
(in 1D, $v$ being the propagation speed of the wave)
It is not invariant under a Galilean…
Tropilio
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Were the Michelson-Morley results a surprise?
How unexpected were the Michelson-Morley experiment results?
Did physicists have theoretical reasons to predict that the speed of light would result to be invariant?
Marco Disce
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Ether vs. Quantum Field Theory
We were asked a question to differentiate the difference between the idea of an Ether and the idea of Quantum Fields. When I really began to think about it I concluded that the ideas are the same. The two are essentially the same idea. They both…
CtrlAltDelete
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Why don't electromagnetic waves require a medium?
As I understand it, electromagnetic waves have two components which are the result of each other, i.e., when a moving electric charge creates a changing magnetic field at point X then a changing electric field is created at point Y and this…
Ryan
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How do electromagnetic waves travel in a vacuum?
This is perhaps a total newbie question, and I will try to formulate it the best I can, so here it goes. How does an electromagnetic wave travel through for example, the vacuum of space?
I usually see that waves are explained using analogies with…
jotadepicas
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Did Einstein know about the Michelson-Morley experiment?
The second postulate of special relativity deals with constancy of light in inertial reference frames. But, how did Einstein come to this conclusion? Did he know about the Michelson-Morley experiment?
Rajath Radhakrishnan
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What is Space in Physics?
Is space a physical thing like matter? Is it a concrete thing or just an abstract concept?
Ajad Ali Mondal
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What is light, and how can it travel in a vacuum forever in all directions at once without a medium?
I know there are many questions that are similar (maybe identical?). I am not a physicist nor a student - I am just interested in physics and have been watching many physics channels on youtube recently in my spare time.
Here is a (nearly) identical…
codefactor
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Isn't LIGO basically measuring the luminiferous aether?
I am bit confused about this one. I am not very acknowledgeable about gravitational waves and LIGO. But if it is basically a Michelson interferometer and can detect shifts in vacuum, doesn't this means that we detected the luminiferous aether and if…
user102977
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Why is it said that light can travel through empty space?
Here are a few commonly heard sentences that will make my question clear:
Statements #1
“The Michelson Morley experiment once and for all did away with the ether or the idea that light needs a medium in which to travel”
“Light can travel through…
Lambda
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Validity of Maxwell's equations with no aether or relativity?
In From Paradox to Reality: Our Basic Concepts of the Physical World by Fritz Rohrlich page 55 it states that
[...] just doing away with the ether would not have resolved all problems. The problems of the validity of Maxwell's theory would have…
user68570
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Why are the Michelson-Morley experimental results interpreted more broadly than the scope of the tested medium?
My understanding of the experimental design is that they tested for a stationary, luminiferous, light propagating, non-interacting with mass, uniform, ubiquitous medium.
This is but one possible definition of a medium. The medium could also be…
GravityTim
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Are Lorentz aether theory and special relativity fully equivalent?
Following up on this question on whether it's possible to construct a physical theory with invariant space-time and variable speed of light.
I am looking for a authoritative and more definitive answer to the hopefully more precise question:
Are…
Three Diag
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Einstein's return to aether
So it seems like that Einstein returned to the concept of aether, but from the point of view of a general relativistic framework.
https://mathshistory.st-andrews.ac.uk/Extras/Einstein_ether/
This is often overlooked by modern theoretical physicists.…
