As time is considered the 4th dimension can we say the 3-d world to be floating(advancing forward in time) in the 4D. If so is every inertial frame has is own velocity rate(moving in the time dimension) in the 4-D. When you have 3-D world if you want to bring 2 objects in contact you can bring them to the same point. But when dealing with 4-d consider this let A and B be start at the same point at t=0 now let B go for a trip and come back. As you can see A and B have their own 3-d layers advancing in time. Because of time dilation after B's return its 3-d layer would be below that of A's isn't it?how can they ever interact again?as they will continue to maintain a distance in the 4-d spacetime(as time rate is the same)?(adsbygoogle = window.adsbygoogle || []).push({});

i m just trying to imagine 4-d spacetime. apologize if the question is non-sensical.hopefully someone can clarify me?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Interaction in 4-D spacetime

**Physics Forums | Science Articles, Homework Help, Discussion**