> Thinking about the future, if humans as a species become interplanetary, keeping up with lunar time, asteroid belt time, martian time,etc.. is going to be a m

> Thinking about the future, if humans as a species become interplanetary, keeping up with lunar time, asteroid belt time, martian time,etc.. is going to be a mess. UTC is the only way to go. You can approximate UTC elsewhere in the universe, but it's going to be weird. You'll have the vary the length of your seconds as your velocity relative to Earth changes. If we regularly have groups of people away from the earth, we'll probably want to follow a time standard that approximates a clock at the center of mass of the solar system.