Your forward land and backward land illustration was great! I completely understand! With the state of things in the US now, it is so comforting to completely understand something. Thank you!

...

Fascinating and flawlessly explained! Every measurement we make has us as suspect and ground zero. Being the observer and creators of any experiment make it to easy to create the desired results. Ironic, how quantifiable and measured theories have to be generally presented and accepted by a group of peers. How many times have theories been laughable at one time and genius at another time. Thoughts, theories and philosophies are immortal that way; we should learn how to look at any and every theory more seriously before history looks back at us and laughs at our self destructive ignorance.

Would the same thing occur if two balls were thrown at the 'same speed'? The observers on the platform would obviously say the time taken to reach two equidistant destinations was different because the train is moving, but what about the people on the train? Would the ball be moving at the same speed from their perspective?

Perspectives and coordinates