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Calendar: from 360 to 365

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When did human beings adopt a 365-day year? Why does a circle have 360 degrees in it? What does one question have to do with the other? The answer has to do with the Global Flood, and how that Flood forced a change in the calendar, long after it happened.

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Calendar history

The English word calendar derives from the Roman Kalends, for the first day of any month. Obviously the only conventional history of calendars is post-Flood history. (History of calendars. (2014, July 1). In Wikipedia, The Free Encyclopedia. Retrieved 18:07 UTC, July 7, 2014, from A casual glance at calendar history from this source shows some interesting trends.

The various civilized powers developed three kinds of calendar:

  1. Lunar calendars. Sumer, Greece (Hellas), and Rome had such calendars. A typical year had twelve months of 29 or 30 days each, for a total of 354 days. To stay current with the seasons, whoever kept the calendar threw in an extra month before the beginning of the next year. In the ancient world, priests or kings kept the calendar. (In Rome the College of Pontifices, or Bridge-builders to the gods, kept the calendar. Highest of these was the Pontifex Maximus, who usually made all the decisions.)
  2. Solar calendars. Ancient Egypt seems to have been first to adopt a proper solar calendar. The first Pharaoh to adopt a solar calendar was probably Amenamhāt I. (See Lockyer J.N., The Dawn of Astronomy, M.I.T. Press, 1894; reprinted 1970.) Then in 48 BC, Julius Caesar came to Egypt, chasing after Pompey the Great. What he did when King Ptolemy XIII's chamberlain handed him Pompey's head in a jar, others have written about. The relevant history here is: Caesar consulted with Sosigenes, court astronomer to Cleopatra VII, about the course of the Sun, the regular flooding of the Nile, and the latitude line called a Tropic that passed through Egypt (specifically through Syene, or modern Aswan). With this knowledge, Caesar invented his all-solar Julian calendar. On his authority as Pontifex Maximus, he inserted 67 days after December of one final consular year (46 BC) before the inauguration of the new consuls (Kalends of January, 45 BC) and ordered that his country keep the new calendar from then on. (He little knew, though he might have guessed, he would die less than fifteen months later.) Caesar proposed adding an extra day every four years without fail; Pope Gregory IX would later revise that when he observed the Julian calendar had fallen ten days behind the seasons. Most of the world uses this Gregorian Calendar today.
  3. Luni-solar calendars. Months in such calendars begin and end, without fail, on the new moon. To stay current with the seasons, these calendars throw in an extra month, or lengthen the last month. The ancient Israelites seem to have lengthened their last month (Adar) by another lunar cycle if the barley was not yet ripe in Jerusalem by the new moon. (Jones F.N., The Chronology of the Old Testament) In 350 AD, the great Rabbi Hillel II invented a nineteen-cycle calendar that would prescribe exactly when to throw in the extra month (Adar Veith or "VeAdar") and when to add a 30th day to the months Tishrei and Marcheshvan (the seventh and eighth months, counting from the Passover month). Remarkably, the Hillel calendar has stayed true to the seasons better than any other calendar now in use, including the Gregorian.

The Egyptian calendar, best of all

The Egyptian case is the most interesting. Lockyer (1894) gave the best treatment of it. The ancient Egyptians originally kept a 360-day calendar with 30-day months. (James Ussher, Archbishop of Armagh, made the same observation while preparing his Annals of the World.) But at some point in Egyptian history, the regular flooding of the Nile River obviously started happening later each year than last. The Egyptians solved this problem by adding extra days to the calendar between their months of Mesori (last) and Thoth (first). (Lockyer, op. cit., pp. 243-8)

But when did the Egyptians make this change? Lockyer quotes one of his authorities, named Krall, on this point:

The calendars of the Mastabas, complete as they are, do not mention the epagomenes, whereas inscriptions of the period of the Amenamhāts refer to them. [This means the extra days] were...introduced in the meantime, but probably nearer the upper than the lower limit.

(The word epagomenon or epagomene is a Greek-derived word, meaning "brought into," for an intercalary day or other interval.)

So maybe Pharaoh Amenamhāt I first started adding the extra day. But why did Egyptian society wait so long? Not more than five hundred years before Amenamhāt (12th Dynasty), the records failed to mention any intercalary days. Lockyer wonders about that, too:

In Egypt, above all countries in the world, owing to the regularity of the inundation, the true length [of the year] was...easily determin[able] [as] soon as that regularity was recognized.

Or in layman's terms: the Nile floods like clockwork at the same time every year, without fail. So of course the Egyptians would have known how long the solar year was, as soon as they realized how regular the Nile flood season was.

Lockyer had a problem. He assumed the solar day has never changed its length, except for intervals we measure in microseconds, and then only after a major earthquake. Everyone around him assumed the same thing. No one had reason to doubt that. So the authorities Lockyer consulted, all assumed the Egyptians adopted a lunar calendar and "brought the lunar month with them." But neither Lockyer nor any of his authorities could figure out why the Egyptians did not figure this out until within centuries of the Exodus of the children of Israel out of Egypt.

But of course Lockyer never considered that a violent event, the only event worthy of the name cataclysm, shorted the day by more than twenty minutes.

The Global Flood and the Calendar

God is a God of order. In Genesis chapter 1 He proclaims His creation of the world "very good." Actually, the Hebrew "mo'ed tov" means more than "very good." It means absolutely excellent!

God is also a Stickler for detail. Everything in God's creation is rich in detail. And any man building something by Divine commission, must pay almost Divine attention to detail.

So why shouldn't we believe God, in making the sun and the moon, gave these two bodies an exacting, regular, and almost resonating cycle? Why shouldn't we believe, in short, that before the Global Flood:

  1. The length of the year was exactly 360 days.
  2. The length of the synodic month, or lunar cycle, was exactly 30 days.
  3. The new year began on the fall equinox (in the northern hemisphere), and with a new moon, without fail.

So what happened? The year never changed its length. (Danny Faulkner was wrong to suggest anyone thought that.) Instead, as Walt Brown (In the Beginning: Compelling Evidence for Creation and the Flood) points out, a subcrustal ocean, thirty miles down, broke containment at what became the Mid-Oceanic Ridge system. This happened within a 200-year interval centered on 3290 BC. After it happened, the continents first drifted, then crashed to the subcrustal chamber floor, then sank. As they sank, the earth spun faster, to conserve angular momentum. So one day went from 1/360 year to 1/365.24 year.

At the same time as the breakout, as much as four percent of the earth's mass, as water, rock and mud, escaped into space. This material went into orbit around the sun. But within weeks, months, years, or even centuries, some of this material fell onto the Moon. In particular, seven large and heavy objects fell to the Moon and caused rock to melt and flow like lava. This formed the Ocean of Storms and the Seas of Rains, Cold, Tranqillity, and Crises, and Humboldt's Sea and the Moscow Sea, among other such smooth land areas.

These impactors struck mostly on one side. That side now faces the earth, from tidal lock. But the impacts also slowed the Moon down. This made it drop into a lower orbit, and one with a shorter period. That's why the synodic month is now aboug 29.5 days. And these days are themselves shorter, by twenty minutes each, than a day before the Flood.

When did this happen? Insight from Project Apollo

This did not happen immediately. The two changes did not even happen concurrently. At least one creation scientist knew this thirty years ago. D. Russell Humphreys (Humphreys DL, "The Creation of Planetary Magnetic Fields," CRSQ, 21(3), December 1984, retrieved from had available the strengths of the remanent magnetic fields from samples of basalt (Apollo 16, Descartes highlands) and brecchia (Apollo 15, crater Dune, Lunar Appenine chain). The magnetic dipole moments of the two samples were remarkably different: 6.3 x 10^21 J/T for the basalt and 1.1 x 10^20 J/T for the brecchia. In contrast, the magnetic dipole moment of the Moon is less than 1.3 x 10^15 J/T. The Magnetic dipole moment of the earth as of 1980 was (7.94 + 0.05) x 10^22 J/T. The magnetic field of the earth was likely much stronger after events associated with the Flood strengthened it. (See below.)

What can these numbers tell us? According to Brown, the earth's magnetic field strengthened tremendously from the melting of the earth's outer core, and the line-up of millions of magnetic dipoles as a result. Something similar might have happened within the objects that formed out of the ejecta from the Flood. The heavier the object, the more magnetic ore it might hold. Basalt had to form from one of the Seven Impactors, or an object not much more lightweight than these. Brecchia would form from a far more lightweight impactor.

These objects took time to form. Seven big rocks did not break off, fully formed, from the edges of the cracked earth's crust, to fall onto the moon the same day they flew out into space. Instead, they formed by accretion, from material that first got far beyond the gravity of the earth or the moon. When they struck, they slowed and dropped the moon to its present orbit. Before they struck, the moon kept the same orbit as before.

In addition, several smaller rocks, no larger than 200 meters in diameter (the length of two World Cup soccer fields), broke off intact. Any one of these could have formed the Dune crater. Its magnetic field strength would have been much smaller; hence the lower remanent magnetism that still exceeds that of the moon.

How much time did the Seven Impactors take to form, coast, and strike? No one can know. But the material that made them must have come from earth. They would not have remanent magnetism so much stronger than the magnetic dipole moment of the Moon itself. Even the free boulders had magnetism stronger than that.


The day, and the synodic month, were both longer than they are today, before, during and after the Global Flood. But the Flood started a process that would shorten the day, and shorten the synodic month even further, over centuries after the Flood. The Egyptians were the best astronomers of their day. They wouldn't make a mistake like that. They were slow to correct that mistake, but not that slow.

Amenamhāt I is a good candidate for the "Pharaoh who knew not Joseph" (Exodus 1:8). Which suggests the calendar was slowly changing itself from shortly after the Flood, through the viziership of Joseph (Imhotep) and to a century or so before the birth of Moses. The Israelites probably kept up with the calendar in the easiest way possible: by observing the phases of the moon and adjusting them by when the barley ripened. So they might have had a good calendar by the time Jacob entered Egypt.