Is the Electromagnetic Field Everywhere?

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In summary, the theory of relativity does not challenge the existence of an ether. It is a limitation of the mind, not the physical model, that we find it difficult to conceive a wave that propagates without a medium. However, nature is indifferent to whether we can understand it or not.
  • #1
phellen
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The theory of relativity makes an 'ether' superfluous, but does it challenge the existence of an 'Ether'. Could the ether be an electromagnetic field or some other unknowable? Or is space-time a kind of ether? Its hard to understand light or even probability waves without a medium in which they are propagated. And whilst sound can travel faster than sound when propagating through
a moving medium, perhaps the fact that light does not do so, tells us something about the light medium. I'm sure these things have been considered millions of times I just wondered what peoples thoughts were.

Thanks
P
 
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  • #2
The fact that people find hard to conceive a wave that propagates without a medium comes to show that the untrained mind is not fully prepared to understand how physics work. Does not mean that the physical models are incorrect though. It's a limitation of the mind, not the model.
 
  • #3
phellen said:
Its hard to understand light or even probability waves without a medium in which they are propagated.

Nature is indifferent to whether we can understand it or not.
 
  • #4
phellen said:
The theory of relativity makes an 'ether' superfluous, but does it challenge the existence of an 'Ether'.
Yes, quite strongly. There are many different kinds of ether models with varying experimental predictions. Most of those have been definitively excluded by experiment. The only remaining ether models which are not excluded are those which are, by ad hoc design, made completely unobservable. This puts it in a category even less scientifically relevant than the Easter Bunny and Santa Claus.
 
  • #5
Does a medium need to be a physical medium? I'm assuming the EM field isn't considered a medium because it isn't physical?
 
  • #6
Why isn't the EM field physical? Last time I used it to stick a baloon on a wall it sure seemed physical to me.
 
  • #7
phellen said:
It's hard to understand light or even probability waves without a medium in which they are propagated.
Hard to understand, perhaps, but not impossible if you think about the way that Maxwell's equations suggest that a falling electric field will produce a rising magnetic field, and a rising magnetic field will produce a rising electric field that can then fall again to keep the cycle going. And if you follow that line of thought, you reach a theory that explains experimental observations more cleanly and usefully than the the ether theories - which is why special relativity was received with general enthusiasm.

And whilst sound can travel faster than sound when propagating through a moving medium, perhaps the fact that light does not do so, tells us something about the light medium.
Indeed it does... it tells us that light behaves more as if it doesn't need a physical medium.
 
  • #8
phellen said:
The theory of relativity makes an 'ether' superfluous, but does it challenge the existence of an 'Ether'.

well, the question Michaelson and Morley must have asked themselves is how is it that we believe in the existence of a physical phenomenon when this phenomenon displays no measurable attributes. it could exist in some form in which it does nothing and makes no difference, but then what's the point? it's the Aether-of-the-Gaps theory.

this is the same question i ask in the Cosmology forum when people bring up the Multiverse as an explanation of some difficult question that is otherwise hard to answer.

Could the ether be an electromagnetic field or some other unknowable? Or is space-time a kind of ether? Its hard to understand light or even probability waves without a medium in which they are propagated.

so if I'm holding a charge and you're holding a charge of opposite polarity, does the fact that you can feel your charge pulled toward my charge indicate that there's a material medium in between? is it hard to understand that, even with a vacuum or total nothingness in between, that it's simply the nature of our two charged bodies to attract each other?

And whilst sound can travel faster than sound when propagating through a moving medium, perhaps the fact that light does not do so, tells us something about the light medium.

relative to the medium, the speed of sound is the same.

but if the experiment shows that no matter what direction the Earth is moving, we measure no difference in the speed of EM propagation, then what does that tell you? it could mean that, somehow, the aether is moving around the Sun along with the Earth in such a way that we aren't moving through it. it does that 12 months a year. and then for the folks who live on the planet Zog, the aether moves around their sun along with them. or maybe not, maybe the Zichaelson-Zorley experiment they performed turned out different than ours? but that would be hard for me to believe.
 
  • #9
Thanks everyone. Nugatory I must look into Maxwells equations :) Dalespam I think I was envisioning the unobservable type of mediums. Perhaps there is something none physical we can't comprehend. Is the em field everywhere? Sorry guys I think I just need to read more about the subject...
Many thanks
P
 
  • #10
phellen said:
Dalespam I think I was envisioning the unobservable type of mediums. Perhaps there is something none physical
Perhaps, but if so then it doesn't matter if we ignore it. Since it is unobservable we will never be wrong by acting as though it doesn't exist.
 
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  • #11
phellen said:
Is the em field everywhere?
P

Yes, all field are everywhere. That's kind of part of the definition of a field. Of course it might be (classically) equal to zero at places but that doesn't mean it's not there.
 
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1. What is Ether and why is it important in scientific research?

Ether is a colorless and highly flammable liquid that was historically used as an anesthetic in medical procedures. However, in modern scientific research, the term "ether" is often used to refer to the hypothetical medium that was once believed to fill all of space and act as a carrier for electromagnetic waves. While the existence of this medium, also known as "luminiferous ether," has been disproven, the concept remains important in understanding the development of scientific thought.

2. Is there any evidence for the existence of Ether?

No, there is currently no scientific evidence for the existence of Ether. In the late 19th and early 20th centuries, experiments such as the Michelson-Morley experiment were conducted in an attempt to detect the presence of ether, but they all yielded null results. This led to the development of Einstein's theory of relativity, which provided a new understanding of space and time without the need for an ether medium.

3. Why was the concept of Ether popular in the past?

The idea of a medium that filled all of space and was responsible for carrying electromagnetic waves was initially proposed by scientists to explain how light could travel through a vacuum. This was a popular idea during the 19th century, as it seemed to provide a logical explanation for the behavior of light. However, as more experiments were conducted and new theories were developed, the concept of ether fell out of favor.

4. Are there any theories that still involve the concept of Ether?

No, the concept of ether is not included in any current scientific theories. However, some fringe theories, such as the "electric universe theory," propose the existence of a different type of ether that is responsible for the behavior of electromagnetic forces. However, these ideas are not widely accepted by the scientific community and lack supporting evidence.

5. How does the rejection of Ether impact our understanding of the universe?

The rejection of Ether as a scientific concept has not significantly impacted our understanding of the universe. In fact, the development of new theories and concepts, such as quantum mechanics and the theory of relativity, have greatly advanced our understanding of the behavior of light and other electromagnetic waves. Additionally, the rejection of Ether has led to a shift in scientific thinking towards more evidence-based and experimental approaches, rather than relying on theoretical concepts that lack supporting evidence.

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