Why have I apparently been friends with someone for 46 years on Facebook?

Originally posted Dec 31, 2015

i see lots of people sharing images wherein facebook tells them they've been friends with someone for 46 years. DO YOU WANT TO KNOW WHY THIS IS HAPPENING? step into my.....


46 years seems really random! but it's not! 46 years ago is the start of "the unix epoch".

keeping track of time on computers is a real pain in the ass-- turns out there are like a billion ways to represent dates and times and time zones and oh god, if you want to make a programmer cry, just start talking about time zones. one method of dealing with the chaos is to represent a specific time as the number of seconds that elapsed between that time and some other reference time.

on posix operating systems (that'd include linux, which runs on many, many web servers, including facebook's, I'd wager), the reference time is the beginning of january 1, 1970 (GMT), also known as "the unix epoch". so, the unix epoch was... 46 years ago. OHO. NOT SO RANDOM AFTER ALL.

so why does facebook think you became friends with someone at the beginning of the unix epoch??? facebook has goofed in some way. it's likely that some chunk of facebook is saying that you became friends with someone at "0", which is to say 0 seconds after the unix epoch, jan 1, 1970. it could be that this chunk of facebook is really trying to say "i don't remember when you became friends with this person", but the "0" is being misinterpreted. alas, dates.