Maxwell and the speed of light

In summary, Maxwell thought that electromagnetism was carried in some kind of luminiferous aether. He produced equations which fit the facts by postulating a mechanical analogue using rotating cells. He did not seem to propose an actual mechanism for EM phenomena. After the Michelson-Morley experiment was conducted, it was found that the speed of light was not constant in different directions. This led to the abandonment of the aether theory.
  • #1
genefalk
13
1
Einstein said that the speed of light is constant for all observers.

When Maxwell derived that the speed of light in the ether was 299,792,458 m/s could he or did he surmise that the speed of light is constant for all observers (regardless of the motion of the source)?
 
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  • #2
genefalk said:
Einstein said that the speed of light is constant for all observers.

When Maxwell derived that the speed of light in the ether was 299,792,458 m/s could he or did he surmise that the speed of light is constant for all observers (regardless of the motion of the source)?
No, it took Einstein to make that leap.
 
  • #3
phinds said:
No, it took Einstein to make that leap.

I'm not sure that's exactly true. It was well known by Einstein's time that Maxwell's equations predicted that speed of light is constant independent of the motion of the source. This was generally thought of as a flaw in the theory and that Maxwell's equations were approximate and would need to be modified. Einstein's contribution was to take this feature seriously.
 
  • #4
Maxwell thought electromagnetism was carried in some kind of luminiferous aether. I suppose it was understood that the speed of light would be relative to the aether. Lorentz eventually came up with a theory in which the speed of light was invariant, but still held on to the concept of aether.
 
  • #5
We are done with aether now, it does not fit with observation.
Dark matter is what though?, not aether but it is there (apparently)
 
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  • #6
Khashishi said:
Maxwell thought electromagnetism was carried in some kind of luminiferous aether. I suppose it was understood that the speed of light would be relative to the aether. Lorentz eventually came up with a theory in which the speed of light was invariant, but still held on to the concept of aether.
May be wrong but not certain that Maxwell did suppose the existence of an aether. He produced equations which fit the facts by postulating a mechanical analogue using rotating cells. He did not seem to propose an actual mechanism for EM phenomena.
 
  • #7
tech99 said:
May be wrong but not certain that Maxwell did suppose the existence of an aether. He produced equations which fit the facts by postulating a mechanical analogue using rotating cells. He did not seem to propose an actual mechanism for EM phenomena.

Maxwell worked a lot in the aether theory. In his 1873 paper "Treatise on Electricity and Magnetism" aether is mentioned as the medium in which EM waves and light propagate. But even at that time the properties of aether were considered sort of magical.

from Wikipedia: https://en.wikipedia.org/wiki/Luminiferous_aether

Wikipedia said:
the aether was hypothesized as the absolute and unique frame of reference in which Maxwell's equations hold. That is, the aether must be "still" universally, otherwise c would vary along with any variations that might occur in its supportive medium. Maxwell himself proposed several mechanical models of aether based on wheels and gears..
 
  • #8
Vanadium 50 said:
I'm not sure that's exactly true. It was well known by Einstein's time that Maxwell's equations predicted that speed of light is constant independent of the motion of the source. This was generally thought of as a flaw in the theory and that Maxwell's equations were approximate and would need to be modified. Einstein's contribution was to take this feature seriously.
Right. That's the "leap" that I was talking about. Maybe it's just me but I've always thought that THAT leap was the hard one and the one he didn't make (that the universe wasn't static) would have been an easier one. I mean, to me the speed of light thing is just weird and it astounds me that anyone could make that leap. 'Course I couldn't have made either one of them I'm sure.
 
  • #9
There have also been many similar discussions in the forum. Take a look at (search results):
https://www.physicsforums.com/search/2848416/?q=Maxwell+and+the+speed+of+light&t=post&o=relevance&c[title_only]=1

All (or many) similar, relevant and enlightening [PF discussions].

+ see bottom of this page.
 
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  • #10
rootone said:
We are done with aether now, it does not fit with observation.
Dark matter is what though?, not aether but it is there (apparently)
None of these fit the observation [yet] (even the LUX experiment for detecting dark matter is failing, even after reaching its maximum resolution). There are also Einstein-aether theories for dark energy, but they are also failing.
Aether was abandoned after the Michelson-Morley experiment ...
 
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Related to Maxwell and the speed of light

1. What is Maxwell's contribution to our understanding of the speed of light?

Maxwell's contribution was the development of the theory of electromagnetism, which explained the relationship between electricity and magnetism and showed that light is an electromagnetic wave with a constant speed of approximately 299,792,458 meters per second.

2. How did Maxwell's equations lead to the discovery of the speed of light?

Maxwell's equations showed that the speed of an electromagnetic wave is determined by the properties of the medium it travels through, such as the electric and magnetic fields. By solving these equations, Maxwell was able to calculate the speed of light in a vacuum, which was found to be the same as the value determined by previous experiments.

3. How did Maxwell's theory challenge previous beliefs about the speed of light?

Before Maxwell's theory, it was believed that light traveled through a substance called the "luminiferous ether", and its speed was thought to vary depending on the motion of the observer relative to this ether. However, Maxwell's equations showed that light has a constant speed regardless of the observer's motion, contradicting this previous belief.

4. How did Maxwell's theory pave the way for Einstein's theory of relativity?

Maxwell's equations were a crucial step towards Einstein's theory of relativity, as they showed that the speed of light is a fundamental constant that is independent of the observer's frame of reference. This idea of a constant speed of light was a key principle in Einstein's special theory of relativity.

5. What are some practical applications of Maxwell's theory and the speed of light?

Maxwell's theory and the constant speed of light have led to many practical applications, such as the development of telecommunication technologies like radio, television, and cell phones. They have also played a crucial role in the advancement of modern physics and our understanding of the universe, including the study of black holes, gravity, and the Big Bang theory.

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