A bomb explodes when I leave the house. The events 'I leave the house' and 'bomb explodes' happen at the same time. These two events happen simultaneously.
When I arive at the bakery a lightning hits my house. The events 'I arrive at the bakery' and 'lightning hits the house' happen at the same time. These two events happen simultaneously.
'Bomb explodes' and 'lightning' do not not happen simultaneously. They are part of two different worlds. One world in the future relative to the other (or one world in the past relative to the other).
Everything happening in a world at a specific moment in time happens simultaneously.
What about a world in which events do not happen simultaneously? That's a 'contradiction in terms'. A world is always made of, and only made of events that happen simultaneously. Events not happening simultaneously are part of different worlds.
=> Go to ....
- Relativity for Dummies
- 4D Spacetime Block Universe
- Reciprocal time dilation
- Reciprocal length contraction
- Lengths do not 'appear' contracted!
- Measuring the contracted train
- Constant light speed
- Where is the bullet?
- Train experiment
- Slower and shorter - case study
- Minkowski vs Loedel
- Spacetime video
- Further reading