Rolle Rant

[Jon Kirwan]

<snip>
Haven't read the chapter, myself. But it certainly reflects
on any "accuracy" claim for the Mayan calendar.

Found the announcement I'd read:

http://www.ia.ucsb.edu/93106/2010/October/research.html

Jon

 

[Martin Brown]

Not more than a few weeks ago, I recall seeing some news item
appearing about a recently published paperback book, this
year:

http://www.amazon.com/Calendars-Years-II-Astronomy-Medieval/dp/184217987X

In a separate chapter on the Mayan calendar, I've read that
Dr. Gerardo Aldana (who is a professor at UCSB and
specializes in Maya hieroglyphic history) says that the
process of converting data between the modern and Mayan
calendars may be wrong by 50 years or even perhaps even a
century.

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.

Haven't read the chapter, myself. But it certainly reflects
on any "accuracy" claim for the Mayan calendar.

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:

http://www.phys.uu.nl/~vgent/eclipse/eclipsecycles.htm

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.

http://en.wikipedia.org/wiki/Ferdinand_Verbiest

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.

http://www.manresa-sj.org/stamps/1_Verbiest.htm

Regards,
Martin Brown

 

[Jon Kirwan]

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!
<snip>

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

Jon

 

[John Devereux]

The science community is perfectly aware that the day is only 86,400
seconds long.

It (the year) is 31,557,600 seconds. That's 365.25 times 86,400.

Averages?

Now I now you are smoking Jimson weed. It is right on the money.
Always has been. There are small arguments about crossing points on a
given rotation, but it is pretty easy to look at centuries of time
passage, and center right in on the figure. Just ask Newton.

The Mayan calendar is accurate to the day on a 13,000 year cycle.
Pretty impressive. They describe the passage of three previous cycles
already.

This is our last gig. Is your house in order? Does it even matter?

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

<http://en.wikipedia.org/wiki/Leap_year>

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

 

[TheGlimmerMan]

You could legitimately believe that to be true during the period when
the Julian calendar was still in regular use before the Gregorian
calendar reforms. The Julian year is still defined that way, but it is
only used for certain crude computations. You are clueless.

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.

 

[TheGlimmerMan]

Haven't read the chapter, myself. But it certainly reflects
on any "accuracy" claim for the Mayan calendar.

Jon

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 shit.

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.

 

[TheGlimmerMan]

Found the announcement I'd read:

http://www.ia.ucsb.edu/93106/2010/October/research.html

Jon

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.

 

[Jon Kirwan]

<snip>
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?
<snip>

http://www.laboratoryequipment.com/news-sow-aldana-101410.aspx
http://abcnews.go.com/Technology/ma...msday-prophecy-wrong/story?id=11926347&page=1

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

Jon

 

[Jon Kirwan]

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.

http://www.laboratoryequipment.com/news-sow-aldana-101410.aspx
http://abcnews.go.com/Technology/ma...msday-prophecy-wrong/story?id=11926347&page=1

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

Jon

 

[TheGlimmerMan]

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

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

 

[Jon Kirwan]

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

 

[Martin Brown]

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?

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

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

You are stupid, ignorant and arrogant in equal measure.

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

365 + 1/4 - 1/100 + 1/400 = 365.2425 days (11s residual annual error)

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:

http://www.timeanddate.com/date/leapyear.html

Regards,
Martin Brown

 

[TheGlimmerMan]

that even you should be able to understand:

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

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

 

[John Devereux]

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"?

 

[John Devereux]

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".