This is my first post in LexLine.  Hello all.

Because I have given a considerable amount of thought to this subject, I would like to offer some  different lines of reasoning regarding a change  the earth related to that 300 day "year".

The first explanation is simply through misinterpretation of ancient script and language.

The second is through the misguided belief that all calendars of the ancients truly represented a full solar year as opposed to a lunar, Venus, or some other means of keeping time with the Heavens.

The third is the one that comes from multiple areas of research, both mine and others', but makes a good, logical case for further inquiry.  No "esoteric knowledge" is required.

While they seem basic and immutable, the factors that determine the length of our solar year, the rotation rate of the planet, the orbital distance from the sun, and the speed of travel around the sun, can be influenced by a small number of factors that could or possibly did exist in our earlier solar system as well as today. The change of 300 days to 365 days, if the result of a change in any or all of the listed factors affecting our year, would have required a period of change that was quite long or else major changes to the ecosystem would have resulted in major extinction events and subsequent rejuvenations -- such as happened 250 million years ago, according to currently accepted paleontology.

Thus, a "sudden" change from 260 days, or 560 days, or 300 days per solar year to 365.25 days is truly an incredible rate of change or jump in any period of less than several eons. Again, we're drawn to notable changes in the way ancient people counted days. Or, perhaps, it's  just how we think they counted or what we think their words meant.

The more enigmatic factor in this discussion is the perceived relationship between the circle and the year. Any people who were capable of devising a mathematical system that describes a number of degrees in a circle were also capable of setting stakes to mark the passage of a solar year and counting the number of sunsets from one event to the next one. Although we certainly have no written records of these efforts, the megalithic, visible monuments to these efforts are widespread.

So how did the ancient mathematicians consistently miscount the number of sunsets by five? Was it simply an accounting error that occurred across all the several cultures and far flung locations that are believed to have had both astronomical or solar observatories and the concept of dividing circles? That seems as implausible as a change in the length of the solar year. Or, was the number of sunsets they counted accurate for the point in history that they were counting them? If the latter, something changed one or more of our orbital or rotation factors resulting in the number of days in a solar year changing by a little more than 1.4%.

In my lifetime, the US Naval Observatory, in cooperation with other astronomical observatories and scientists, have "added" time to the solar year on multiple occasions, terming the addition "leap seconds". Thus, the year, or at least the way we mark it, is lengthening measurably within one lifetime.

Going back to the idea that a major change in any of factors that affect the perceived length of our solar year would have drastic affects on the global ecosystem, let's examine the end of the ice age, or, more correctly, the beginning of the current interglacial period. During an glacial accumulation, the ice forms in the, polar sub-polar, and in the temperate zones closest to the poles. Much like a figure skater, when the mass is drawn closer to the axis of rotation, the rotational rate increase and when the skater extends the arms further from the axis, the rotational rate decreases. So when we're discussing a significant portion of the planet's water being held in glaciers  at or near the polar regions, we might expect an increase in the rotational rate of the planet and when that ice melts and shift back towards equatorial latitudes, we might expect a decrease in the rate.

There would almost certainly be a latency or "lag" between those related events and, in effect, they become self- regulating and self-balancing, even though this interplay probably requires many thousands of years to play out.

One last thing that could, theoretically, affect the length of our year is an extraterrestrial impactor. If such an impactor struck a glancing blow while traveling (from the Earth perspective) from West to East, it could impart extra rotational torque and thus increase the rotation rate of the planet and more sunsets in the "year". Travel in the opposite direction would result in a decrease in rate and fewer sunsets in the same solar orbit.

Enter the work of Alan West and his colleagues. They postulate and have gathered ample evidence that such an impact occurred in the Great Lakes region of North America approximately 10,900 bce. Again, any abrupt change to any of the factors that determine the length of our solar year would result in major changes to the ecosphere and extensive extinctions.  The one that occurred 10,900 bce is generally termed the "Pleistocene-Holocene extinction event".

Firestone, R. B., et al. "Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and Younger Dryas cooling." Proceedings of the National Academy of Sciences 104, October 9, 2007c, 16016 -16,021. [http://www.pnas.org/cgi/doi/10.1073/pnas0706977104].

Am I completely convinced? Hardly. But I am convinced we should not close our minds to the possibility that there were factors in our early pre-histroy that drove humans to perceive a solar year that was then different than it is today.