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Q & A: relativity and light

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Most recent answer: 07/27/2008
Q:
I am a sceptic of relativity theory and am trying to become a believer. As far as I know (about this theory), time slows down when some one travels at the speed of light. What about blind people ? Will this effect happen for them as well ?.. I am curious because blind people have nothing to do with light.
- Vijay (age 38)
Bombay, India
A:
The special theory of relativity really concerns how the physical variables (distance, velocity, mass, etc.)  measured by one observer are related to similar variables measured by an observer in uniform motion with respect to the first one. It turns out that a special speed, "c", enters into the rules for transforming variables between these different observers. It happens that one thing with which we are familiar, light, travels at that speed. That made it easy for Einstein to make up simple explanations for the rules, using descriptions of what different observers would see. If nothing travelled at the speed c, the rules would be unchanged. We would just need different stories to explain them. The ability of any person to see light does not change these basic rules.

Mike W.

(published on 07/27/2008)

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