There is a disagreement between astronomers and historians about how to count the years preceding year one; astronomers count the BC years astronomically. Thus, the year before the year 1 is the year 0, and the year preceding the latter is the year -1 (2 BC, 1 BC, and one are, astronomically, -1, 0, and 1, respectively). The year which the historians call 585 BC is actually the year -584. The astronomical counting of the negative years is the only one suitable for arithmetical purpose. For example, in the historical practice of counting, the rule of divisibility by 4 revealing the Julian leap-years is no longer valid; these years are, 1 BC, 5 BC, 9 BC, 13 BC... In the astronomical sequence, however, these leap-years are called 0, -4, -8, -12..., and the rule of divisibility by four subsists. In this system we can speak, for instance, of the solar eclipse of -1203-08-28 (twenty-eighth day of August in the year 1204 BC), although at that remote time the Roman Empire was not yet founded and the month of August was still to be conceived!
Also, the (politically?) correct way to specify BC is "Before Common Era", while AD (Anno Domini) is now CE (Common Era). A good reference is Astronomical Algorithms by J. Meeus and published by Willmann-Bell, Incorporated Post Office Box 35025, Richmond, VA 23235. Heck, according to the Mayan calendar, everything's kaput in five years anyway! (at least, I THINK we have five years) ________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Krištof Želechovski Sent: Tuesday, 2007 August 28 10:48 To: 'Rikkert Koppes'; [email protected] Subject: Re: [whatwg] (no subject) I think arithmetic notation for dates B.C. is unintuitive and hard to understand (also because in terms of dates -1+1=1). It would be better to present a B.C. check box, or just say it aloud if dates A.D. are not expected. Chris -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Rikkert Koppes Sent: Tuesday, August 28, 2007 10:39 AM To: [email protected] Subject: [whatwg] (no subject) - are negative years allowed (B.C.)? the datetime description tells me "four or more digits (0 to 9) representing the year" which implies "no". use case: hystory questionary Regards, Rikkert Koppes
