I have a few questions about time dilation due to gravity. It seems to me there are some strange/interesting consequences of this that I've never seen discussed. I'm not sure what signifigance it has, but it seems like it should have some. Basically, since gravity is lower on the surface of Mars than on the surface of Earth, then time should procede faster on Mars than on Earth (relative to each other). I know this difference is too small for a human lifetime to be significant, but it seems like it should add up to something serious on a geological time scale. Even more so for smaller planets (or non-planets) like Pluto. Doesn't this mean that they are some large number of years ahead of us in geological development in some sense? That the surface of those planets is in some sense a lot older than the surface of Earth (relative to the start of the solar system and each other)? Like I said, I don't know if this has any meaning other than a possible science fiction story plot, but it seems interesting at least. It might have implications though if we find some old Martian rock on Earth (which has happened) and try and figure out "when" it left Mars and came to Earth. If that was long enough ago, that "when" could be radically different from an Earth and from a Mars perspective. Also, this just let me to another thought. Time speeds up as you get closer to the center of the Earth for the same reason. Doesn't this have some sort of weird implications for geological development of the planet, where the center of the Earth is going to be quite a bit older geologically than the surface of the planet? Over several billion years this difference has to be pretty serious. Do geologists ever consider this when thinking about planetary geology theories?