The Present
Since there are no days in space we wear watches that tell us not only the time but how old we are. That’s how we know when to celebrate our birthdays, not that we do, having used up the cake mix centuries ago. But while clearing space slugs from the hull I had an accident, losing one hand and with it the watch. They gave me a new hand and a new watch but checking the age I saw I was ten years younger than I should be. I told the repair-bot but she just smiled and said happy birthday.