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Adel Makram
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Why is c invariant for all FORs? Special R took it as a postulate but it did not explain it,,,
Adel Makram said:Why is c invariant for all FORs? Special R took it as a postulate but it did not explain it,,,
DrGreg said:Before Einstein, Lorentz and others took the view that length contraction and time dilation of objects moving through an aether explained the invariance of the speed of light.
Einstein took the opposite view that the invariance of the speed of light explained length contraction and time dilation. Under that view, there is no explanation for the invariance of the speed of light, that's just a fundamental symmetry of the universe we happen to live in.
Physicists quite like explanations in terms of symmetry.
If A logically implies B and B logically implies A, then you can choose to say "A causes B" or "B causes A".salvestrom said:And the invariance of c is only possible due to time dilation and length contraction.
Adel Makram said:Why is c invariant for all FORs? Special R took it as a postulate but it did not explain it,,,
salvestrom said:Eesh, anyone know a shorthand for that? How about "the phenomenon"?
jtbell said:Lorentz symmetry.
DrGreg said:If A logically implies B and B logically implies A, then you can choose to say "A causes B" or "B causes A".
So I could just as easily say "time dilation and length contraction are only possible due to the invariance of c."
Nugatory said:It's a postulate, so it would be easy (and unhelpful) to say that it doesn't have to be explained. You choose a postulate, you apply some logic, you get some results that are valid assuming the postulate is valid, and you're done.
Adel Makram said:Why is c invariant for all FORs? Special R took it as a postulate but it did not explain it,,,
Mark M said:SR took the invariance of the speed of light as a an assumption, though Einstein did not explain why he singled out light as a special case (Probably because electromagnetism was the only known field at the time).
See post #3 in this thread for a better explanation:
https://www.physicsforums.com/showthread.php?t=445032
Adel Makram said:Why is c invariant for all FORs? Special R took it as a postulate but it did not explain it,,,
The concept of C invariance is frequently asked about in the fields of physics and chemistry. Here are five commonly asked questions about why C is invariant, with explanations:
C invariance, or charge conjugation symmetry, is a fundamental principle in physics that states that the laws of physics remain unchanged under the transformation of particles into their antiparticles. This means that the properties and behaviors of particles and their antiparticles are symmetrical.
C invariance is important because it is a fundamental symmetry of the universe that helps us understand the behavior of particles and their interactions. It is a key concept in the Standard Model of particle physics and is used to explain many physical phenomena, such as the conservation of energy and the behavior of the strong and weak nuclear forces.
C invariance is closely related to other symmetries, such as time reversal symmetry and parity symmetry. Together, these three symmetries form the CPT symmetry, which states that the laws of physics remain unchanged when particles are transformed into their antiparticles, time is reversed, and space is inverted.
In most cases, C invariance is conserved, meaning that the laws of physics remain unchanged under particle-antiparticle transformations. However, there are a few exceptions, such as in certain types of weak interactions, where C invariance is violated. This violation is known as CP violation and is still an active area of research in particle physics.
C invariance has many practical applications, especially in medical imaging and technology. For example, positron emission tomography (PET) scans use the concept of C invariance to detect and visualize the distribution of positrons (the antiparticles of electrons) in the body. It is also used in the development of particle accelerators and other advanced technologies.