Jc3s5h added a comment. The phrase "Gregorian ISO value" requires further consideration. For example, does it mean an ISO 8601 compliant value, or the strings currently in use which resemble ISO 8601 but permit a number of violations, such as "2015-**00**-**00**T00:00:00Z"?
Also ISO 8601 requires the Gregorian calendar, which is a solar calendar based on counting actual sunrises and sunsets. For events in the distant past, most astronomy and other science is based on constant-length seconds such as produced by an atomic clock (see the Wikipedia article "Delta T". The difference between these two approaches grows to a full day about the year 3400 BC. Thus ISO 8601 is not fit for use in prehistoric times. TASK DETAIL https://phabricator.wikimedia.org/T117031 EMAIL PREFERENCES https://phabricator.wikimedia.org/settings/panel/emailpreferences/ To: Jc3s5h Cc: Jc3s5h, aude, daniel, Aklapper, Smalyshev, jkroll, Wikidata-bugs, Jdouglas, Deskana, Manybubbles _______________________________________________ Wikidata-bugs mailing list Wikidata-bugs@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikidata-bugs