Talk:Maya calendar/Archives/2012/October

Malmstrom an Ureliable Source

The article cites Malmstrom several times: Malmström (1997)

"[http://www.dartmouth.edu/~izapa/CS-MM-Chap.%206.htm Chapter 6: The Long Count: The Astronomical Precision

I read the cited article a long time ago. I used it as an example of terrible scholarship in one of these discussions but I didn't remove it. I reread it today and it's really awful. I'm not going write a detailed critique of it because would take too long to describe the very many errors but the problems are that it contains assertions that are thoroughly disproven, it contains very many careless errors that disagree with the mainstream scholarship, it has very few citations, it contains many original theories that are based on the authors conjectures and its very self-promoting. Rather that demonstrating Malmstrom's knowledge of the Maya calendar it demonstrates his ignorance. The references section also has a link to the whole book:

Malmström, Vincent H. (1997). Cycles of the Sun, Mysteries of the Moon: The Calendar in Mesoamerican Civilization. Austin: University of Texas Press. ISBN 0-292-75197-4. OCLC 34354774. Retrieved 2007-11-26. {{cite book}}: templatestyles stripmarker in |author= at position 1 (help)CS1 maint: numeric names: authors list (link)

I haven't read the whole thing but even my cursory look created very large reservations about using as it as a reference. I was also alarmed recently to read that Malmstrom is a proponent of theories connecting the origin of the Olmec with old world cultures. Removing pseudoscientific sources will improve the article. I propose to remove the references to Malmstrom from the article. Senor Cuete (talk) 16:56, 24 September 2012 (UTC)Senor Cuete

I don't think we can discount the source as unreliable, it is peer reviewed and published by a university press. However, Malmstrom's view is clearly not the predominant one when it comes to the origins of Mesoamerican calendars. I don't know enough about his work to have any opinion about how well it concords with Maya calendrics, but I would prefer to see some comments by professionals to that effect (e.g. Book reviews) before I discount it as being simply wrong and erroneous. Being a proponent of pseudoscientific or dubious claims in one area should not necessarily be taken as indicative of general quackery. Michael D Coe for example is also a believer in trans-pacific contact as an influence in Mesoamerican and Latin American indigenous cultures. ·ʍaunus·snunɐw· 15:12, 25 September 2012 (UTC)

I just read a mostly positive review in Ethnohistory. It is certainly not considered pseudoscience by peers in the field. I think we should describe his theory, but make it clear that it is not widely accepted.·ʍaunus·snunɐw· 15:21, 25 September 2012 (UTC)

From the Tzolkin article - "Vincent Malmström identifies a correlation between the 260-day cycle and the 260-day gap between zenith and transits of the sun. According to this hypothesis, the 260-day cycle originated in the narrow latitudinal band (14°42′N to 15°N) in which the sun is vertically overhead about 12–13 August and again 260 days later about 30 April-l May (Malmström identifies the proto-Classic Izapan culture as one suitable candidate at this latitude). This period may have been used for the planting schedule of maize. However, others object to this conception, noting that while the 260-day calendar runs continuously the interval between autumn-spring and spring-autumn positions alternates between 260 and 105 days, and that the earliest-known calendric inscriptions are from considerably further north of this zone. Consequently this theory is not widely supported." It appears that peer revue is negative in this case. Senor Cuete (talk) 15:26, 25 September 2012 (UTC)Senor Cuete

I DO know enough about Maya calendrics to revue it. Just a casual glance at the linked chapter shows ignorance of Maya calendrics, wild fringe theories about the Long Count, self promotion and lack of citations. For example he says "the coastal regions of Colima, Jalisco, and Nayarit continued to enjoy closer cultural bonds with South America". "...the 52-year cycle has been called the "Short Count," especially by researchers working with the Maya. However, the association of the Short Count with the Maya is only accurate of their final period of decadence and decline..." Actually the Short Count is an abridged version of the Long Count. It has nothing to do with the Calendar Round. "(All Mesoamerican cultures believed that the world had existed in four earlier epochs..." Actually the Popul Vuh says it was three. Only post-classic calendars used four. Then he goes on to say that this creation will end on a four movement, citing unreliable sources. He then proceeds to state his fringe theories that the origin of the Long Count was based on the Calendar Round, the Thompson correlation is correct, the Tzolk'in is correlated to the Long Count and there is a grand Cycle of 13 Bak'tuns. None of this is referenced. All of this is contrary to the content in the Maya calendar and Long Count articles. If this doesn't convince you maybe you should read the chapter in his book about the magnetic Olmec heads. Senor Cuete (talk) 16:02, 25 September 2012 (UTC)Senor Cuete

I maintain that we should base our decision of how to allocate due weight on how the work has been received, not on what we personally think of it. So if he is not cited then that is a sign it hasn't been received well. We should look more into whether his work is cited in the main works on Maya calendrics. If it isn't then neither should we.·ʍaunus·snunɐw· 16:38, 25 September 2012 (UTC)

Agreed per WP:NPOV if not referred to in the main works, not significant. Dougweller (talk) 05:12, 26 September 2012 (UTC)

From the Tzolk'in article: "However, others object to this conception, noting that while the 260-day calendar runs continuously the interval between autumn-spring and spring-autumn positions alternates between 260 and 105 days, and that the earliest-known calendric inscriptions are from considerably further north of this zone. Consequently this theory is not widely supported." Read the linked pdf. It seems that his theory about the origin of the Tzolk'in received a less-than-warm reception from others in the field. Senor Cuete (talk) 14:28, 26 September 2012 (UTC)Senor Cuete

Chapter 6 of Malmstrom contains a theory, that the creation date was selected to coincide with the zenith passage of the Sun at the latitude of Copan and Iztapa and that the Tzolk'in is 260 days long because a zenith passage of the Sun occurs with a 260 day interval at that latitude. He claims that this occurs on August 13, not 11, proving that the Thompson correlation (584285 days) is correct. He ignores the fact that neither the proleptic Julian astronomical (used by astronomers) nor the proleptic Gregorian (used by archaeologists) calendar uses a year equal to the tropical year and that August 13 today is not the same date in the tropical year as it was 5,125 years ago - although it is closer in the proleptic Gregorian calendar. In checking his theory one can ignore this by using the Julian day number of the relevant dates + .25 for time zone -6 and ignore Local Sun Time to Greenwich Standard Time conversion. Chapter 25 - Solar Coordinates in Astronomical Algorithms second edition by Jean Meeus has an easy to program method for calculating the Sun's right ascension and declination. This method calculates that at noon on Julian Day Number 584286 (August 14, 3114 BC Gregorian - September 9, -3113 Julian Astronomical) the Sun's apparent declination at noon was 14.8937 decimal degrees, close to the zenith at Copan - latitude 14.8395 degrees north and also Iztapa - latitude 14.9234. So the zenith passage date at these sites was close to but not coincident with creation of the current world using either the GMT or Thompson correlation. 261 days later, not 260, on julian day number 584547 the Sun was again close to the zenith at these sites. One must wonder how accurately this could have been be observed since the angular diameter of the Sun is +/- 32 arc minutes or 0.5 degrees, its declination was changing about .3 degrees per day and its position doesn't coincide with noon on any particular day. Also Malmstrom claims to have written computer programs to check his theories. Apparently he didn't do it with this one. This is an example of the futility of trying to prove or disprove a correlation using astronomy. If anyone has an astronomy program that you could use to check my calculations I encourage you to do so. Senor Cuete (talk) 15:22, 4 October 2012 (UTC)Senor Cuete

The year 3314 BC is so far away that all the calculations related to counting of days and calendars may be wrong by several days. There is no way of knowing which was the ΔT so far in the paste. Every calculation we can do is nothing more than useless.Japf (talk) 00:09, 5 October 2012 (UTC)

ΔT would make a difference if very high accuracy was required but not for this analysis. I have a book that has algorithms that consider the gravitation of the planets, etc. and contain many more terms. These can be used to calculate this with high accuracy back to 3,000 B.C. Maybe I'll code that as well. Senor Cuete (talk) 23:24, 5 October 2012 (UTC)Senor Cuete

The delta-T dependence on the interaction with the Moon is well known indeed, but there is other component which depends on the rising of continental masses after the end of ice age, and even now that component is important. You can have all the accuracy you want if you use the International Atomic Time, but you couldn't make sure if some phenomenon happened in the 584286 Julian day or one day before or after, because you can't know for sure how many leap seconds happened (surely in the magnitude of hundred thousands). Please read this, where it is said "but the uncertainties grow so rapidly that no meaningful results can be obtained earlier than about 2000 BCE". Anyway, I am only saying that the calculations of Malstrom are meaningless, but other calculations made by other people are meaningless also. I believe that the algorithms you use can handle with delta-T, but for 3114 BC they are surely outside of the range of validity for the determination of delta-T.Japf (talk) 00:05, 6 October 2012 (UTC)

From the previous paragraph we could conclude one thing: If we from the technological 21st century can't say exactly when an astronomical phenomenon happened 5000 years ago, neither did the stone-age mayas from the 5th century BC.Japf (talk) 00:11, 6 October 2012 (UTC)

Long Count illustration

The image of La Mojarra Stela 1 in the Long Count section is a bad example of a Long Count inscription. It's one of the earliest Long Counts known, in epi-Olmec script. It's not typical of Mayan Long Count inscriptions which are written in two columns preceded by a two column wide initial series introductory glyph. For this reason in the Long Count article it was moved to a section about the earliest Long Counts and the illustration was replaced with the illustration of Quirigua stela C. The Quirgua inscription is an excellent example of a Classic Maya Long Count inscription. I think the La Mojarra stela should be replaced with the Quirgua stela in this article as well. Also the articles don't explain the typical form of a classic inscription - ISIG, two columns, etc. Comments? Senor Cuete (talk) 16:55, 21 October 2012 (UTC)Senor Cuete

Nobody objected to this edit so I changed it. Senor Cuete (talk) 16:16, 26 October 2012 (UTC)Senor Cuete