Rolle Rant

Found the announcement I'd read:

Jon

Possibly true. Although it can only be wrong by certain fixed amounts since it is a calendar founded on the Sun-Earth-Moon eclipse configuration (integer multiples of Saros and Inex). The Hebrew and Arabic calendars were also more accurately aligned with reality than the Romans Julian calendar for similar reasons.

They were pretty good astronomers and had established some of the better known eclipse periodicities (as had the Babylonians and Chinese). I wouldn't demean the Mayan efforts - they almost certainly did a far better job of computing their calendars than the Romans!

The known eclipse periodicities and their physical interpretation along with a summary of which ones were thought to have been know to the ancients is online at:

Since they had an observational tie in to the rather precise alignment needed for a solar eclipse (less so for a lunar eclipse) there is every reason to suppose their calendar keeps good time even over a few thousand years. What is less clear is the mapping between their dates and our dates - historians could easily have got that wrong.

It is a bit easier in China as they also recorded novae and in 1670 the Jesuit priest Ferdinand Verbiest managed to defeat their by then rather lazy out of touch royal astronomers in an eclipse predicting competition. The loser was cut up into little bits whilst still alive.

It is an amazing story not least because the Chinese made wood block prints of all the European mediaeval technology that Verbiest used to re-equip Peking observatory and several of these still survive today. Chinese cannons with "Verbiest fecit" on them have been found too - he was quite a character and very knowledgeable.

Regards, Martin Brown

I was speaking to accuracy relative to the modern calendar and more specifically the 2012 date, only. Not precision nor quality of work.

Jon

It constantly amazes me how you can be so confident and yet so wrong.

I still remember reading about this stuff when I was about 13! One of Isaac Asimovs science fact columns I think (RIP).

You are, as it is obvious that you missed the .25 day figure which is there, included. Where is that in your claim of my knowledge of a calendar?

Oh... that's right... it was YOU that missed it.

You're an idiot, and you are expounding on crap you haven't even read.

That is amazing that a dumbfucktard like you goes around pulling such a blatantly stupid, Obama-esque move.

You are dumber than dog s*it.

If it is so far off, as you state, then why is it matching up, to the very day as to when or solar system crosses through the galactic equatorial plane?

It doesn't get much dumber than an easily manipulable twit like you.

From your first response in this thread and then from examining the link it is obvious that you have drawn the wrong conclusions about what the author is saying.

His recent work challenges the accuracy, for very specific reasons.

Jon

His recent work challenges the accuracy, for very specific reasons.

Jon

Your double posting challenges your credibility, not that you ever had any.

That's you making a mountain out of a mole hill -- looking for anything at all, in your apparent desperation for saying anything substantial in response.

But my credibility never was the issue. The links stand on their own and luckily do not depend upon me for anything.

Jon

The Julian year is defined as 365.25 days but it isn't used much now.

You are stupid, ignorant and arrogant in equal measure.

The civil year as presently defined by the Gregorian leap year rules is:

The divide by 400 rule for leap years caught out one major UK bank in the year 2000 and as a result some of their bank cards used on 29th February and 31st December were invalidated. Japan had more bother than most with quite a few systems crashing and going offline from Y2k2.

Had Pope Gregory chosen 365 + 1/4 - 1/128 = 365.241875 it would have been considerably more accurate with 0.45s residual annual error and a lot easier for hardware calendar chip makers and software.

This website explains the tropical solar year and calendars using short words that even you should be able to understand:

Regards, Martin Brown

I knew about it in 1969 at nine years of age, asshole.

Even you should have enough brains to understand the math on that.

On the contrary, it's used extensively in astronomical formulae. The Julian Day is a continuous count of days since January 1, 4713 BC Greenwich noon, with a "year" length defined to be 365.25 days; no leap seconds or other adjustments. As such, it represents a well- behaved time index for the formulae, which would otherwise have to be much more complex; All the 'glitches' are remanded to the calendar conversions.

And the proportion of astronomers using these these formulae to the general population would be..... "not much"?

What proportion of the population uses an oscilloscope?

The tools of any given trade are mostly only relevant to that trade. That doesn't make them any less useful or important to those who do need and use them.

I don't think that is a fair analogy, since only a tiny minority of the general population are electronic engineers. But a very high proportion of the general population *do* use calendars - just not that one! Given that most of the world has not used it for a few hundred years, it seems entirely reasonable to say it is "not used much now".

I think that you may be confusing Julian Day Numbers with the Julian Calendar. They are not the same thing. In fact, they are even named for two entirely different people named Julius!

I just had a wild thought... Rolle's Theorem proves that Laffer was right ;-) ...Jim Thompson

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