Maxwell's equations and relativity

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Discussion Overview

The discussion centers around the relationship between Maxwell's equations and the theory of relativity, exploring both special and general relativity. Participants examine how electromagnetism is integrated into relativistic frameworks and the implications for classical mechanics.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants propose that the electromagnetic field tensor unifies Maxwell's equations within the framework of special relativity.
  • Others argue that while classical electromagnetism is compatible with relativity, classical Newtonian mechanics is not, necessitating a reformulation of mechanics for relativistic contexts.
  • A viewpoint suggests that electromagnetism, as described by Maxwell's equations, served as a catalyst for the development of special relativity.
  • Some participants question the relationship between Maxwell's equations and Newton's law of gravity, noting that Maxwell's equations do not align with Newton's law.
  • One participant asserts that Newton's law remains a useful approximation in many scenarios despite the advancements of general relativity.
  • Another participant emphasizes that Maxwell's equations can be expressed in terms of special relativity without directly involving gravity.

Areas of Agreement / Disagreement

Participants express differing views on the connections between Maxwell's equations, Newton's law, and general relativity. There is no consensus on the nature of these relationships, and the discussion remains unresolved regarding the implications of these theories.

Contextual Notes

Participants highlight the need to differentiate between theories, particularly regarding the roles of electromagnetism and gravity in the context of relativity. There are references to the limitations of classical mechanics when applied to relativistic scenarios, but these remain open for further exploration.

Zac Einstein
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what is the connection between maxwell's equations and relativity?
 
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Zac Einstein said:
what is the connection between maxwell's equations and relativity?

Using the framework of special relativity, you can construct a tensorial quantity called the electromagnetic field tensor. It unifies the Maxwell equations in an elegant way, showing that they are essentially part of one simple object. You should read this article for an introduction:

http://en.wikipedia.org/wiki/Covariant_formulation_of_classical_electromagnetism" .
 
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Polyrhythmic said:
Using the framework of special relativity, you can construct a tensorial quantity called the electromagnetic field tensor. It unifies the Maxwell equations in an elegant way, showing that they are essentially part of one simple object. You should read this article for an introduction:

http://en.wikipedia.org/wiki/Covariant_formulation_of_classical_electromagnetism" .

Thank you, sir
 
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Classical Newtonian mechanics is incompatible with Einsteinian relativity, so we basically have to re-write the laws of mechanics to make them relativistically correct.

Classical electromagnetism, on the other hand, is already compatible with Einsteinian relativity, so we don't have to re-write the laws of electromagnetism except to gain a more elegant formulation as Poly described.
 
Let's call electromagnetism based on Maxwell equations the igniting factor for a new theory of dynamics, the one put forth by Einstein, Poincare and Lorentz and later generalized by Einstein under the name of <General Relativity>.

In one phrase, special relativity emerged because of electrodynamics and is encoded in the 4 equations for the E and B fields.
 
Let's call electromagnetism based on Maxwell equations the igniting factor for a new theory of dynamics, the one put forth by Einstein, Poincare and Lorentz and later generalized by Einstein under the name of <General Relativity>.

In one phrase, special relativity emerged because of electrodynamics and is encoded in the 4 equations for the E and B fields.

Classical Newtonian mechanics is incompatible with Einsteinian relativity, so we basically have to re-write the laws of mechanics to make them relativistically correct.



General Relativity is another gravity theory...but why do some people still use Newton's law of gravity, according to General Relativity Newton didn't know how gravity works so Newton's law is not true.
Maxwell's equations doesn't agree with Newton's law too.
Right?
 
Zac Einstein said:
General Relativity is another gravity theory...but why do some people still use Newton's law of gravity, according to General Relativity Newton didn't know how gravity works so Newton's law is not true.
Maxwell's equations doesn't agree with Newton's law too.
Right?

Because Newton's law is a good and simple approximation to general relativity that is applicable in numerous situations. Just because a new theory is better, it doesn't mean the old one is completely false.
Maxwell's equations have nothing to to with Newton's law.
 
Polyrhythmic said:
Because Newton's law is a good and simple approximation to general relativity that is applicable in numerous situations. Just because a new theory is better, it doesn't mean the old one is completely false.
Maxwell's equations have nothing to to with Newton's law.

Yes sir, I didn't mean that it's completely false and if it was completely true Einstein didn't have to develop a new theory, am I right, sir?

You said "Maxwell's equations have nothing to to with Newton's law" how come that there's a connection between general relativity and Maxwell's and no connection between Maxwell's and Newton's law of gravity sir?
 
Zac Einstein said:
Yes sir, I didn't mean that it's completely false and if it was completely true Einstein didn't have to develop a new theory, am I right, sir?

Yes.

You said "Maxwell's equations have nothing to to with Newton's law" how come that there's a connection between general relativity and Maxwell's and no connection between Maxwell's and Newton's law of gravity sir?

Let's not mix theories here. Maxwell's equation can be formulated nicely in terms of special relativity. You interpret classical fields in terms of relativistic tensorial quantities and take advantage of an elegant formalism. This alone has nothing to do with gravity, neither with Newton's nor Einstein's equations.
 
  • #10
Zac Einstein said:
General Relativity is another gravity theory.[...]

Not only that, it's much more, it's a theory of dynamics, which is a part of classical mechanics.
So it goes like:

Newtonian mechanics for inertial reference frames < Special Relativity < General Relativity

... < Electromagnetism in flat space-time < Electromagnetism in curved space-time ( = in the presence of gravity).
 
  • #11
Let's not mix theories here. Maxwell's equation can be formulated nicely in terms of special relativity. You interpret classical fields in terms of relativistic tensorial quantities and take advantage of an elegant formalism. This alone has nothing to do with gravity, neither with Newton's nor Einstein's equations

Ah, I guess I have to study Maxwell's again :confused:

Thank you for answering me sir :smile:
 

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