1). the product of the two masses being gravitationally attracted to each other
2). the distance between their centers of mass
And that's IT. The gravitational force between them depends on
only those two things, nothing else.
The Gulf Stream, for example, has an average speed of 4 mph, or 100 miles/day, or 3600 miles/year, in round numbers. A complete circuit around the Atlantic is 8 or 10 thousand miles, which would take around 3 years on a raft.
You can try to explain it by using a parallel between their and your societies .
