After Epoch Astronauticum

The AEA (After Epoch Astronauticum) calendar (also known as the EA or Era Astronauticum calendar) is a simple, non-religious calendar based on a historic event. The event in question is the first (known :>) landing of an inhabitant of the Earth on the surface of another planetary body, namely the Apollo 11 moon landing.

Although you could tell time by the AEA calendar in years months, etc. it is convention to specify AEA dates in seconds, or more specifically Megaseconds (1 Megasecond (Msec) = 1 million seconds) (one of the reasons for this being that the calender was thought of with future space missions and colonies in mind where Earth based time units wouldn't be too usefull), thus if you see an AEA date without a unit on it you can assume it to be in Msec. They are also generally specified to three digits after the decimal point like so: 970.392 this gives you not only the date but the time of day as well. As odd as that may sound these dates are actually suprisingly conveniant to use. The trick being that each digit in the date represents a reasonabally useful period of time. (see approximations below.)

Note that times before the AEA epoch are denoted as negative numbers. (for example the start of the Christian (common Era) calender (1 A.D.) is -62168.500 AEA)

Another thing to note is that for various technical reasons (ease of converting to Common Era calendar, as well as inaccuracy of records concerning Apollo 11, and indecision regarding which event in the mission is "the" date (Eagle touchdown or Armstrong disembarking 6-3/4 hrs later)) the Epoch for the AEA calendar is actually defined as Midnight (00:00:00), Greenwich Mean Time on New Years day of the first Common Era year following the moon landing. thus 0.000 AEA is 00:00:00 GMT, Jan 1970 rather than some time between 12:15:00 and 19:00:00 GMT, Jul 20 1969

Approximations

AEA date/times are measured in megaseconds, and can be broken into conveniant parts fairly easily thusly:

970.398 Msec AEA
^^^ ^^^
||| |||_________ Time of "day"
||| |___________ Day of "week" 
|||_____________ Week of "year"
||______________  "Year"

here are the conversions (FYI: Megasecond (Msec) = 1 Million sec, Kilosecond (ksec) = 1000 sec = 0.001 Msec, and the symbol ~= is short for "Approximately equals")

• 0.001 Msec (1 Ksec) ~= 15 Minutes (Actually 16-2/3 min)
• 0.100 Msec (100 Ksec) ~= 1 day (actually 27-3/4 hrs)
• 1.000 Msec (1 "week") ~= 10 days (actually 11-1/2 days)
• 10.000 Msec ~= 1/3 year (actually 115 days)
• 1000.000 Msec ~= 1/3 Century (actually 32-1/2 years)

Timeline:

Who uses it?

• I use it :> I date my webpages w/ it.
• SF author Vernor Vinge is known touse it under varous names in his novels.
• In what I would assume to be shear coincidence, Unix operating systems internally represent dates in a format that exactly corrosponds to the AEA calendar (tho it's in seconds, not megaseconds) (the so-called "time_t" format)
• due to above coincidence many programming languages and databases use this format too
• Others...? email me.
• You can :>