Iv been trying to get my head around the special theory of relativity and i think i may have found the particular part of the theory i do not understand; that being relativity of simultaneity.(adsbygoogle = window.adsbygoogle || []).push({});

I was on a train recently, sitting about half way in the carriage, and i noticed two led clocks at either end. I related these two clocks to the two lightning strikes of Einstein's thought experiment, concerning relativity of simultaneity. I considered if exactly half way in the carriage and that the train was at rest than, the passing of the minutes would be considered to be simultaneous, but if the train where moving, this would not be the case. The clock closer to the driver, when the train has velocity would appear to change its digits before the other clock.

This then caused a headache, as i realised this conclusion was inconsistent with the theory. If i was on a train that traveled at 1/2C and the carriage i am in is 3 light seconds long (according to an outside observer), being half way the clock closest to the driver, would be one light second behind a clock in my position and the clock at the other end, would be 3 seconds behind a clock in my position. As i am able to tell that these two clocks are equidistant from my position, I could determine an absolute velocity. This outcome defies the assumption that one can not determine absolute speed and that each inertial frame of reference has equal right in considering itself at rest.

Where have I gone wrong with my understanding relativity of simultaneity?

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Relativity of simultaneity: the source of the headache

**Physics Forums | Science Articles, Homework Help, Discussion**