How does time run on planet when I'm gone?

I have built a farm on - well, more like within - an asteroid field. When crops grew in my absence (when I was on another planet), I thought the game simply adds delta time to their growth when opening the map.

But I crafted some sprinklers and it works as well. When I come back, the soil is moist and the plants are grown by more than one stage. So apparently, time DOES pass when I'm gone, it's not some simple adding numbers to plant age. I also noticed food decays in my absence in chests.

Does it calculate/simulate all time passed when it loads the map? Or are the other maps running in background?

How does it work?

Time in Starbound does not continue on planets if you leave them. The game unloads planets and maps after ~10 minutes. This is detectable by a number of methods:

• Checking starbound.log or terminal output (it will list that Planet xxxxxxxxx has been unloaded)
• The on-planet day/night cycle resets after the planet has been unloaded.
• The time you have to get back in missions before they reset is the same time, as loading them is done by a similar method.

As for your specific question, the game does store data about it's planets in the games universe folder. I assume it simply does delta substraction for a crops total time. Crop growth is measured in real time, not on-planet time.