This document is part of the Martian Time Boneyard. It was originally located at http://www.marsengineering.com/Calendar/Birthsols.asp.
Author: Shaun Moss

Birthsols

Birthsols (Martian birthdays) for emigrants can be determined by converting the Earthly date-of-birth to a Martian date. For example, for someone born on 1971-October-29, this converts to 192-Bootes-07. Therefore, this person would be 15 mirs old at the time of writing (208-Virgo-07), and will turn 16 mirs old in 1 month.

It's possible, perhaps even likely, that emigrants to Mars will continue to celebrate birthdays in accordance with the yearly cycle of Earth, and think of their age in terms of Earth years. However, this probably won't be the practice of future generations born on Mars.

Leap babies

Having the leap sol at the end of year raises the question, when will Martian leap babies (those born on the leap sol, Ophiuchus 25) celebrate their birthsols? In the Gregorian calendar, most leap babies (people born on February 29) celebrate their birthday on February 28 in non-leap years. A few celebrate their birthdays on the following day, March 1 - however, if this were done on Mars, this would mean celebrating the birthsol on the first sol of the following mir, resulting in no birthsol in some mirs, and two birthsols in other mirs. The logical solution is for those born on Ophiuchus 25 to always celebrate their birthsol on New Mir's Eve.