Origin is the date-time for 1970-01-01 UTC in POSIXct format. This date-time
is the origin for the numbering system used by POSIXct, POSIXlt, chron, and
Date classes.
origin
An object of class POSIXct (inherits from POSIXt) of length 1.
Examples
origin
#> [1] "1970-01-01 UTC"