There is a simple inference to formula for time dilation on Wikipedia. On this simple inference they take two scenarios:
- Observer on the moving frame where the height is represented by letter "H"
- Observer on a "stationary" frame where the height is also represented by "H"
My question is: how is possible to assume that on the two scenarios the height is a constant "H" and don't get any king of space transformation?
I have been calculate the same but without assume the "H" constant and get: $$ \Delta T' = \frac{\frac{H'}{c}}{\sqrt{1 - \frac{v^2}{c^2}}}$$
where H' is the height of object viewd from a "stationary" frame.
If H'=H than the formula become the traditional: $$ \Delta T' = \frac{ \Delta T}{\sqrt{1 - \frac{v^2}{c^2}}}$$
So my question is: "How can I assume that the height doesn't change with velocity?
in other words... how is H'=H ?"
Remember: The theory of relativity says about lengh contraction, so is totaly valid think about height contration (or dilatation).
Why is the height constant with velocity and length not?