"RFC 9557: Date and Time on the Internet: Timestamps with Additional Information" https://www.rfc-editor.org/rfc/rfc9557.html https://www.rfc-editor.org/rfc/rfc

"RFC 9557: Date and Time on the Internet: Timestamps with Additional Information" https://www.rfc-editor.org/rfc/rfc9557.html https://www.rfc-editor.org/rfc/rfc9557.html 1996-12-19T16:39:57-08:00[America/Los_Angeles] > The offset -00:00 is provided as a way to express that "the time in UTC is known, but the offset to local time is unknown" 1996-12-19T16:39:57-00:00 1996-12-19T16:39:57Z > Furthermore, applications might want to attach even more information to the timestamp, including but not limited to the calendar system in which it should be represented. 1996-12-19T16:39:57-08:00[America/Los_Angeles][u-ca=hebrew] 1996-12-19T16:39:57-08:00[_foo=bar][_baz=bat] Astropy supports the Julian calendar – circa Julius Caesar (~25BC), born by Caesarean section (an Eastern procedure)), and also astronomical numbering which has a Year Zero. [1] There is still not a zero in Roman numerals; there's "nulla" but no zero. Modern zero is notated with the Arabic numeral 0. [1] Year Zero, calendaring systems: https://wrdrd.github.io/docs/consulting/knowledge-engineering#common-era-ce https://wrdrd.github.io/docs/consulting/knowledge-engineerin... astropy.time > Time Formats: https://docs.astropy.org/en/latest/time/#time-format https://docs.astropy.org/en/latest/time/#time-format Which calendar is the oldest? List of calendars: https://en.wikipedia.org/wiki/List_of_calendars https://en.wikipedia.org/wiki/List_of_calendars Epoch > Calendar eras: https://en.wikipedia.org/wiki/Epoch#Calendar_eras https://en.wikipedia.org/wiki/Epoch#Calendar_eras -- Are string tags at the end of the datetime that indexable? Shouldn't there be #LinkedData URLs or URIs in an RDFS vocabulary for IANA/olsen and also for calendaring systems? E.g. Schema.org/dateCreated has a range of schema.org/DateTime, which supports ISO8601, which also specifies timezone Z (but not -00:00, as the RFC mentions). Astounding that there's been no solution for calendar year date offsets on computers. Are there notations for indicating which system, or has everyone on earth also always assumed that bare integer years are relative to their preferred system? Somewhere there's a chart of how recorded human history is only like 10K out of 900K (?) years of hominids of earth, through ice ages and interglacials like the Holocene.