 #1
Ad VanderVen
 156
 10
 TL;DR Summary

Suppose we have an expanding sphere. That means that the surface ##4 \Pi r^{2}## is getting bigger and bigger. For example, suppose the area expansion rate is ##b r##. Does this limit the speed at which a point can move on the surface?
Reference: https://www.physicsforums.com/forums/specialandgeneralrelativity.70/postthread
Suppose we have an expanding sphere. That means that the surface ##4 \pi r^{2}## is getting bigger and bigger. For example, suppose the area expansion rate is ##b \, r##. Does this limit the speed at which a point can move on the surface?