simple equation
time = f(distance, connection)
= C * sqrt(1-distance)/(1-connection)^4
C: pre-factor, roughly 1 (day)
notes:
- distance is normalized: 0-->1 (0 is you couple together; 1 you couple in different planets)
- connection is normalized: 0-->1 (0 no love at all; 1 is infinite love between you couple)