Two fun asides: 1) Latitude on another planet is straightforward: take the rotational equator, divide into 90 degrees north and south, done. But what about Lon

Two fun asides: 1) Latitude on another planet is straightforward: take the rotational equator, divide into 90 degrees north and south, done. But what about Longitude? Here on Earth, the prime meridian is Greenwich, because reasons. On Mars, it's indexed to a certain crater. But on the gas giants? Yeah, we still don't have a good plan about that. 2) Paul Krugman's thesis (yes, that Paul Krugman) is on relativistic economies. As in, my planet is in a deep gravity well, your's isn't. My clocks pas a lot slower. Now, how do I calculate interest? What about letters of credit for ships traveling between places to ship goods? His conclusion: let's hope there isn't money by then, because interest can't work between relativistic time frames.