# Can different observers observe different realities?

The question is extention of thought experiment proposed by Einstein of light pulses in a train cart called Einstein's train. Assume that light pulses are emitted from the end of cart, instead from the center, such that stationary observer, sees the light pulses at the center crossing each other at the same time. image of this case from real experiment is given here And now let there a new observer which has a relative motion between cart and himself. So similarly to this case, the new observer will see that two pulses, coming at the center, in two different instants of time. Now there are two things

1. I can consider two pulses crossing each other at the center as a single event because they have same spacetime coordinates. So events don't change in relativity but here they are apparently. Because now the event is non-existential here in any other frame than the stationary one. (Light pulses don't reach at the center at the same time) So where is that, I am getting wrong?
2. It's consequences can change reality. For example if I place a detector at the center and what it does is, it (making it dramatic) kills the schrodinger's cat (I know the name looks familiar) in the glass box placed at the center, if it records that two pulses have reached at it simultaneously. (Since it is placed in the cart at the same spatial point with the center, we can approximately say that detection and killing is simultaneous). But for everyother observer the cat would be alive. Why?
• Your question says light pulses are emitted from ends but your image shows that it's emitted from the center. Jul 30 '20 at 20:13