Time is that thing that goes on when you are too busy hunting aluminum . All joking aside, time is important to know in Xenominer as it tells you if it is safe to go out without being roasted by solar radiation . You do not need a fancy item that needs to be crafted, you can check the time with the digital clock in the bottom left corner of your HUD.
A day lasts 24 hours. You will get 12 hours of day and 12 hours of night. Day starts at 6:00 AM and ends at 6:00 PM.