B Einstein's Epiphany of Constant Light Speed

thetexan
Messages
269
Reaction score
13
How did Einstein first contemplate the idea that the speed of light was constant in all frames or reference?
Did he say "I wonder what would happen if we considered light speed to be constant" in some kind of thought experiment. Did the concept fall serendipitously from the results of calculations?

I'm just wondering how it would occur to someone to think of that when additive velocities were just generally assumed. The very idea of a constant light speed was so bizarre in that realm of thought that I'm curious, especially when time being a linear constant was so accepted. I'm sure the story is out there but I can't find it.

tex
 
Physics news on Phys.org
The idea that the speed of light was constant actually predates Einstein I believe. If I remember correctly, it dates back to the mid-1800's when classical electrodynamics was developed fully and certain problems were noticed. See here: https://en.wikipedia.org/wiki/History_of_special_relativity
 
thetexan said:
How did Einstein first contemplate the idea that the speed of light was constant in all frames or reference?
Did he say "I wonder what would happen if we considered light speed to be constant" in some kind of thought experiment. Did the concept fall serendipitously from the results of calculations?

I'm just wondering how it would occur to someone to think of that when additive velocities were just generally assumed. The very idea of a constant light speed was so bizarre in that realm of thought that I'm curious, especially when time being a linear constant was so accepted. I'm sure the story is out there but I can't find it.

tex
It was an observation. Experiments showed the speed of light is invariant.

Relativity was an explanation

Sent from my SM-G550T2 using Physics Forums mobile app
 
thetexan said:
How did Einstein first contemplate the idea that the speed of light was constant in all frames or reference?

I think he claimed it came from his study of electromagnetism. If a loop of wire is moved relative to a stationary magnet a current arises in the wire. And if a magnet is moved relative to a stationary loop of wire a current arises in the wire. Einstein was able to show that these two interactions are the same, a symmetry that was lacking in the laws of electrodynamics.
 
  • Like
Likes vanhees71
Mister T said:
I think he claimed it came from his study of electromagnetism. If a loop of wire is moved relative to a stationary magnet a current arises in the wire. And if a magnet is moved relative to a stationary loop of wire a current arises in the wire. Einstein was able to show that these two interactions are the same, a symmetry that was lacking in the laws of electrodynamics.
This is what I gathered from reading On the Electrodynamics of Moving Bodies.

Edit- might as well post it to save someone a google search.

https://www.fourmilab.ch/etexts/einstein/specrel/www/
 
  • Like
Likes vanhees71
I asked a question here, probably over 15 years ago on entanglement and I appreciated the thoughtful answers I received back then. The intervening years haven't made me any more knowledgeable in physics, so forgive my naïveté ! If a have a piece of paper in an area of high gravity, lets say near a black hole, and I draw a triangle on this paper and 'measure' the angles of the triangle, will they add to 180 degrees? How about if I'm looking at this paper outside of the (reasonable)...
The Poynting vector is a definition, that is supposed to represent the energy flow at each point. Unfortunately, the only observable effect caused by the Poynting vector is through the energy variation in a volume subject to an energy flux through its surface, that is, the Poynting theorem. As a curl could be added to the Poynting vector without changing the Poynting theorem, it can not be decided by EM only that this should be the actual flow of energy at each point. Feynman, commenting...
Back
Top