In page 138 of the rulebook, it says:
CALCULATING TRAVEL TIMES
Interplanetary distances are measured in Astronomical
Units (AU). The distance between two planets is calculated
◆◆ SHORTEST DISTANCE: The difference between the planets’
individual distances from the sun.
◆◆ FARTHEST DISTANCE: The sum of the planets’ individual
distances from the sun.
◆◆ Divide the distance in AU by the spaceship’s speed to get
the travel time (in number of days).
How do we tell the distance in AU between planets? It feels like this calculation is missing a step.