The table below shows various periods, from one day up to the largest known, and period glyphs for some of them. Some periods do not have glyphs, because we’ve never seen them; the largest known date on the monuments is
13.13.13.13.13.13.13.13.13.13.13.13.13.13.13.13.13.13.13.13.0.0.0.0
at Coba^{}, and the Mayans only carved the numbers, not the associated period glyphs.
The table goes up to the largest cycle shown at Coba, but since we don’t have a clue what the names of any of these huge periods were, I’ve simply lettered them. The largest one, then, is the “N” cycle. Just to give some idea how large a number this is, the Earth weighs approximately 66 sextillion tons, which fits between the “H” and the “I” cycles. There are probably more days in the Coba date than atoms in the universe. .^{}
K’in (Kin) 1 Day LC[0] 



Winal (Uinal) 20 Days LC[1] 


Tun 360 Days The “computing year” LC[2] 


K’atun (Katun) 7,200 Days 20 computing years 20^{1} Tuns LC[3] 


Bak’tun (Baktun) 144,000 Days 400 computing years 20^{2} Tuns LC[4] 


Piktun (Pictun) 2,880,000 Days 8,000 computing years 20^{3} Tuns LC[5] 

Kalabtun (Calabtun) 57,600,000 Days 160,000 computing years 20^{4} Tuns LC[6] 

K’inchiltun (Kinchiltun) 1,152,000,000 Days 3,200,000 computing years 20^{5} Tuns LC[7] 

Alawtun (Alautun) 23,040,000,000 Days 64,000,000 computing years 20^{6} Tuns LC[8] 


“Hablatun”
^{}
460,800,000,000 Days 1,280,000,000 computing years 20^{7} Tuns LC[9] 
460 billion 800 million Days; 1 billion 280 million Tuns  
“A” 9,216,000,000,000 Days 25,600,000,000 computing years 20^{8} Tuns LC[10] 
9 trillion 216 billion Days; 25 billion 600 million Tuns  
“B” 184,320,000,000,000 Days 512,000,000,000 computing years 20^{9} Tuns LC[11] 
184 trillion 320 billion Days; 512 billion Tuns  
“C” 3,686,400,000,000,000 Days 10,240,000,000,000 computing years 20^{10} Tuns LC[12] 
3 quadrillion 686 trillion 400 billion Days; 10 trillion 240 billion Tuns  
“D” 73,728,000,000,000,000 Days 204,800,000,000,000 computing years 20^{11} Tuns LC[13] 
73 quadrillion 728 trillion Days; 284 trillion 800 billion Tuns 

“E” 1,474,560,000,000,000,000 Days 4,096,000,000,000,000 computing years 20^{12} Tuns LC[14] 
1 quintillion 474 quadrillion 560 trillion Days; 4 quadrillion 96 trillion Tuns 

“F” 29,491,200,000,000,000,000 Days 81,920,000,000,000,000 computing years 20^{13} Tuns LC[15] 
29 quintillion 491 quadrillion 200 trillion Days; 81 quadrillion 920 trillion Tuns 

“G” 589,824,000,000,000,000,000 Days 1,638,400,000,000,000,000 computing years 20^{14} Tuns LC[16] 
589 quintillion 824 quadrillion Days; 1 quintillion 638 quadrillion 400 trillion Tuns 

“H” 11,796,480,000,000,000,000,000 Days 32,768,000,000,000,000,000 computing years 20^{15} Tuns LC[17] 
11 sextillion 796 quintillion 480 quadrillion Days; 32 quintillion 768 quadrillion Tuns 

“I” 235,929,600,000,000,000,000,000 Days 655,360,000,000,000,000,000 computing years 20^{16} Tuns LC[18] 
235 sextillion 929 quintillion 600 quadrillion Days; 655 quintillion 360 quadrillion Tuns 

“J” 4,718,592,000,000,000,000,000,000 Days 13,107,200,000,000,000,000,000 computing years 20^{17} Tuns LC[19] 
4 septillion 718 sextillion 592 quintillion Days; 13 sextillion 107 quintillion 200 quadrillion Tuns 

“K” 94,371,840,000,000,000,000,000,000 Days 262,144,000,000,000,000,000,000 computing years 20^{18} Tuns LC[20] 
94 septillion 371 sextillion 840 quintillion Days; 262 sextillion 144 quintillion Tuns 

“L” 1,887,436,800,000,000,000,000,000,000 Days 5,242,880,000,000,000,000,000,000 computing years 20^{19} Tuns LC[21] 
1 octillion 887 septillion 436 sextillion 800 quintillion Days; 5 septillion 242 sextillion 880 quintillion Tuns 

“M” 37,748,736,000,000,000,000,000,000,000 Days 104,857,600,000,000,000,000,000,000 computing years 20^{20} Tuns LC[22] 
37 octillion 748 septillion 736 sextillion Days; 104 septillion 857 sextillion 600 quintillion Tuns 

“N” 754,974,720,000,000,000,000,000,000,000 Days 2,097,152,000,000,000,000,000,000,000 computing years 20^{21} Tuns LC[23] 
754 octillion 974 septillion 720 sextillion Days; 2 octillion 97 septillion 152 sextillion Tuns 

The Coba Number 10,331,233,010,526,315,789,473,682,240,000 Days 28,697,869,473,684,210,526,315,784,000 computing years 
10 nonillion, 331 octillion, 233 septillion, 10 sextillion, 526 quintillion,
315 quadrillion, 789 trillion, 473 billion, 682 million, 240 thousand Days 28 octillion, 697 septillion, 869 sextillion, 473 quintillion, 684 quadrillion, 210 trillion, 526 billion, 315 million, 784 thousand Tuns 
^{} Coba is a ruin in northeastern Yucatan, near Tulum, sixty miles or so from Chichén Itza; during Classic times, it was the largest city in the area (Hunter, 1986).
^{}
Well, not really. I did some checking on the number of atoms in the universe. Here’s what I found:
MessageId: <Pine.ULT.3.91.960404110732.18731V100000 at mmlds1.pha.unc.edu> Date: Thu, 4 Apr 1996 12:18:03 0500 From: Iosif Vaisman <> Subject: Re: Help# atoms universe To: Multiple recipients of list CHMINFL On Wed, 3 Apr 1996, R. Scott Jokerst wrote: > The calculation is not possible. Any credible astronomer will tell you > they have no idea what the mass of the universe is, at any level of > approximation. It’s size is also undetermined, and keeps getting “bigger” Not exactly. Some quite credible astronomers have some ideas. E.g.:  AUTHOR: Jungman, G.; Kamionkowski, M.; Kosowsky, A.; Spergel, D.N.  TITLE: Weighing the Universe with the cosmic microwave background  SOURCE: Physical Review Letters, vol.76, no.7, p. 100710 (1996)  AUTHOR: Carvalho, J.C.  TITLE: Derivation of the mass of the observable Universe  SOURCE: International Journal of Theoretical Physics, vol.34, no.12,  p. 25079 (1995)  AUTHOR: Tardif, J.  TITLE: A method for the estimation of the mass of the universe  SOURCE: Speculations in Science and Technology, vol.17, no.2,  p. 135136 (1994)  AUTHOR: Loh, E.D.; Spillar, E.J.  TITLE: A measurement of the mass density of the Universe  SOURCE: Astrophysical Journal. Letters to the Editor, vol.307, no.1,  pt.2, p. L14 (1986)  AUTHOR: Peebles, P.J.E.  TITLE: The mean mass density of the Universe  SOURCE: Nature, vol.321, no.6065, p. 2732 (1986)  AUTHOR: Peebles, P.J.E.  TITLE: The mass of the Universe  SOURCE: Ann. New York Acad. Sci. (USA), Annals of the New York  Academy of Sciences, vol.375, p. 15768 (1981) As to the number of atoms in the Universe Neil de Grasse Tyson in his “Universe down to Earth” (Columbia University Press, 1994) writes about 10^81. Other recent estimates range between 10^70 and 10^90. Of course, few atoms here and there may be not accounted for. Iosif Vaisman http://www.unc.edu/~ivaisman
So then I did some calculations, using Python, a fullfeatured programming language available for Unices, Linux, Mac and Windows OSs. ** is used for exponentiation, and _ means to substitute the previous answer in the formula.
Here are my results:
Python 2.4 (#60, Nov 30 2004, 11:49:19) [MSC v.1310 32 bit (Intel)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>> 20**21 2097152000000000000000000000L >>> _*360 754974720000000000000000000000L >>> 10**70 10000000000000000000000000000000000000000000000000000000000000000000000L >>> 10**81 1000000000000000000000000000000000000000000000000000000000000000000000000000000000L >>> 10**90 1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000L >>>
So I was a little off .
^{} The “Hablatun” name has only been reported by Spinden, so it is very unlikely to actually have been in use. In fact, all terms for periods larger than k’atun should be viewed with a skeptical eye. K’atun and smaller periods shown in the table are attested to and used by Mayans, but bak’tun seems to be an invention of Mayanists rather than Mayans. Recent advances in translation have shown that the glyph for the 144000day period should most probably be translated as pi or pih, a term meaning “bundle.” None of the terms for periods greater than 144000 days are attested. They should be recognized for what they are: terms invented for the convenience of Western anthropologists, archaeologists and epigraphers. See any of the recent Notebooks by Linda Schele (et al.) for a detailed discussion.
Gates, William E., An Outline Dictionary of Maya Glyphs, Johns Hopkins Press, 1931.  
Hunter, C. Bruce. A Guide to Ancient Maya Ruins: Second Edition, Revised and Enlarged. Norman: University of Oklahoma, 1986 (first edition 1974).  
Schele, Linda and Nikolai Grube, Notebook for the XXIst Maya Hieroglyphic Workshop, “The Dresden Codex,” Department of Art and Art History, The College of Fine Arts, and The Institute of Latin American Studies, University of Texas, Austin, 1997.  
Schele, Linda, Nikolai Grube and Simon Martin, Notebook for the XXIInd Maya Hieroglyphic Forum, “Deciphering Maya Politics,” Department of Art and Art History, The College of Fine Arts, and The Institute of Latin American Studies, University of Texas, Austin, 1998.  
Schele, Linda and Peter Matthews, “Numbers,” Unpublished Chapter III of Maya Writing Book, Maya File 212, n.d.  
Spinden, Herbert J., “The Reduction of Maya Dates,” in Papers of the Peabody Museum of American Archaeology and Ethnology, Harvard University, Vol. VI, no. 4, Peabody Museum, 1924, pp. 1286.  
Spinden, Herbert J., A Study of Maya Art: Its Subject Matter & Historical Development, Dover, New York, 1975. (Original publication 1913; With a New Introduction & Bibliography by J. Eric S. Thompson.) 



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