In Tom's world your car is made of events of cars from different car worlds. In the sketch I have made the car a long green car to better visualize what's happening in Tom's world (blue space). Of course the principle also works for a small green car, but then I had to zoom in on the car....
The sketches make relativity of simultaneity visible, but in reality a lot more happens. Relativity of simultaneity also leads to time dilation and length contraction. For example: in Tom's world (blue space) the green car is shorter than the train in your world (white space).
I prefer not to write that the car 'contracts' because that sounds a bit as if the car of a world contracts -shrinks- in that world. That's not the case. The 'contraction' is due to relativity of simultaneity of events! That's very imortant te keep in mind.
Relativity of simultaneity is reciprocal. Length contraction is reciprocal. So is time dilation. For you, in your worlds, Tom's time runs slower. But in Tom's worlds your car time runs slower. Not only the relativity of simultaneity, but also the length contraction and time dilation keep the speed of light constant. Unfortunately it is too complicated to show this in my Spacetime maps. My Spacetime maps are 'Minkowski diagrams' and suffice to explain relativity of simultaneity (and the shortening of the green car on this page) but are very clumsy to show space or time dimensions. If you really want to dig into Special Relativity, such as time dilation and length contraction, and especially the reciprocity of length contraction and time dilation, I recommend you to use the geometry of a 'Loedel diagram'. (Search on Google for more info on the Loedel diagram. You will also find a link in my Further Reading section).
Time to get back to our main topic.
=> 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