dates Before Present, but "m.y." for the duration of epochs. This ad hoc distinction between "absolute" time and time intervals is somewhat controversial amongst members of the Geological Society of America. See also : current year Astronomical year numbering Century Decade Epoch (reference date) ISO 8601: standard for representation of dates and times List of calendars List of years Millennium Orders of magnitude (time) Unit of time Annual References Notes Further reading External links Images of years