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DonB
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Hello. I am an occasional poster here with little background but a big interest in the mental experiments (ME) of Einstein and others. Of particular interest to me are factors related to what I call the Classic Spaceship Mental Experiment. [mentor's note: a link to an unacceptable reference under the Physics Forums rules has been removed]
From previous discussions (some here) I understand that it is generally accepted (and correct me if I'm wrong) that:
1) Nothing can exceed the speed of light relative to any given "rigid point" (Einstein's term);
2) In a vacuum electricity travels through a wire at the speed of light.
That being the case, for a spaceship traveling at/near the speed of light relative to the earth, if an observer (O1) inside the spaceship turns on an electrical switch allowing electricity to flow from a battery located in the rear of the spaceship to a light bulb in his compartment, he will see the light come on since the electricity is traveling within the ship at c relative to him. However, an observer (O2) on the Earth arguably will not be able to see the light come on since it would require electricity to travel at 2c relative to him.
Now let's take this ME to a more down to Earth scenario. For a jet traveling at mach one, the electricity that runs the length of the fuselage is c relative to the pilot (O1). But according to our two givens above, since electricity can't travel at >c relative to O2, it must travel at <c relative to the fuselage as observed by O2 (i.e., no faster than c - mach-one)? So O2 would here see variations in lights and/or instrument readouts due to the abnormal speed of electricity relative to the jet? And would only the speed of electricity flow in the direction of flight be 'warped,' but the flow from the light back to the battery be normal?
The ramifications of the two givens seem to demand unworkable scenarios. So where is my thinking wrong on the ME above?
From previous discussions (some here) I understand that it is generally accepted (and correct me if I'm wrong) that:
1) Nothing can exceed the speed of light relative to any given "rigid point" (Einstein's term);
2) In a vacuum electricity travels through a wire at the speed of light.
That being the case, for a spaceship traveling at/near the speed of light relative to the earth, if an observer (O1) inside the spaceship turns on an electrical switch allowing electricity to flow from a battery located in the rear of the spaceship to a light bulb in his compartment, he will see the light come on since the electricity is traveling within the ship at c relative to him. However, an observer (O2) on the Earth arguably will not be able to see the light come on since it would require electricity to travel at 2c relative to him.
Now let's take this ME to a more down to Earth scenario. For a jet traveling at mach one, the electricity that runs the length of the fuselage is c relative to the pilot (O1). But according to our two givens above, since electricity can't travel at >c relative to O2, it must travel at <c relative to the fuselage as observed by O2 (i.e., no faster than c - mach-one)? So O2 would here see variations in lights and/or instrument readouts due to the abnormal speed of electricity relative to the jet? And would only the speed of electricity flow in the direction of flight be 'warped,' but the flow from the light back to the battery be normal?
The ramifications of the two givens seem to demand unworkable scenarios. So where is my thinking wrong on the ME above?
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