Author Andy Weir told his Facebook followers —
According to the crew stats that were in the Ares 3 Live video “The Right Stuff” Mark Watney’s birthday is October 12, 1994.
That means today is Mark’s 21st birthday! So right now he’s an undergrad at University of Chicago working toward a biology degree. Also he’s probably very drunk.
(If you squint, you can see Watney’s birthday in an infographic at :37.)
Although Weir posted a photo of a birthday cake, some commenters said they’d be eating a potato in Mark’s honor today.
[Thanks to Joseph T. Major for the story.]