As 2020 comes to a close, it's just seven weeks to Christmas

M.T. Cranium · 22-12-2014 7:53pm #1

To amplify on the widely discussed point of Christmas adopting the rituals of Saturnalia and other non-Christian winter solstice festivals, it is my belief that Jesus was born around the end of what is now February in the year 7 B.C. (or 6 B.C.E. if that includes a year zero A.D.) and here's my rationale for this.

As is fairly widely known, Jesus was not born in the year 1 B.C. or as some might style it, 0 A.D., that error was introduced by a sixth-century monk in calculating the dates for the new numbering system that was to replace the old Roman custom of numbering years from the founding of Rome, or the Jewish system which dates back almost four thousand years before Christ. We know this because Herod died in 4 B.C. and he was actively searching for the newborn infant Jesus for two years. This makes the most likely date around 6 or 7 B.C. -- further obscurity is introduced by the fact that most historians use a numbering system that goes directly from 1 B.C. to 1 A.D. whereas most astronomers use a system that includes a year never actually observed by anyone at the time, 0 (zero) A.D. -- if you look in a table of astronomical data you will find dates in that year but if you do, you need to realize that it is the same year that a historian would call 1 B.C. That means that an astronomical event in 6 B.C. would take place in 7 B.C. historical time.

Now, what happened in that year to attract my attention? I believe that the mystery of the guiding star and the three wise men may be an allegory for an event that only trained astrologers (the ancient astronomers) would have known about in those times. The two brightest planets, Venus and Jupiter, made a very close conjunction in the post-sunset sky in February of (astronomical) 6 B.C. or historical 7 B.C. Their closest approach was on February 13 during the daylight hours (Jerusalem time). Observers would not have seen this because the two planets were so close to the Sun, but trained astrologers would have known where they were. Somewhat further away from the Sun, the planets Uranus, Saturn and Mercury were all in the general vicinity.

My theory that the Biblical narrative is allegory can be explained as follows. Venus is clearly an allegory for Mary, the mother of Jesus. Jupiter could be seen as an allegory for Jesus and/or for God. However, the ancients did not necessarily know that Uranus existed (they may have done so as that planet can be seen in very clear dark skies by people with good vision, and it's possible that knowledge of it was lost in the Dark Ages). This comment is relevant because I theorize that the three wise men did not physically exist, but were allegories for the three planets following along behind this unseen event in the solar glare. Alternatively, Jupiter could be one of the three wise men and Saturn and Mercury, known and quite visible in the dark skies of antiquity, were the other two. Gold, frankincense and myrrh could be allegories for their appearances or significances. (Jupiter is clearly the best choice for gold).

Now, all of these planets were setting just after the Sun, hence the concept of westward procession. The idea that this mysterious light appeared in the time when shepherds were in their fields (tending to newborn lambs) would be a better fit for February than December also. Weather conditions in the Judean high country at that time of year can often be relatively bland, suitable for staying outdoors with a bit of protection from the chill. Is this a bit earlier than some might expect the event? Not by more than a year and there is already considerable uncertainty within a range of several years. How about the part of the story where the "star" comes to rest over Bethlehem? That part may be an embellishment of the narrative and not meant to signify anything.

There is even a hint of this narrative in the subsequent story that Jesus was recognized in the temple by two elders, one of whom was eighty-four years in age (a very advanced age in those times). The period of the planet Uranus is exactly that, 84 years. And the part where Jesus was twelve years old, more or less the period of Jupiter which is 11.86 years. Does this mean I think the entire story is allegorical? No, I believe Jesus was a real historical figure but that these birth and childhood narratives took on allegorical meanings for effect. This is not to say that three savants from a distant location did not undertake a journey to Bethlehem to salute the newborn child, but they would have known about the significance of Bethlehem (and more generally the Jerusalem area) from the Old Testament prophecies of where the Messiah would originate.

My source for all the astronomical data is the Skyglobe program. This is actually shown in historical rather than astronomical dates, there is no zero (0) A.D. in the program. Running it ahead a few days, Jupiter and Uranus converged as they both passed behind the Sun on February 21st, meanwhile Venus which was emerging from its own passage behind the Sun in that January was passing close to Saturn on February 23rd. It probably became visible as an evening star to keen observers by mid-March, Jupiter appeared in the morning skies by April of that year. Mercury was heading in front of the Sun (and considerably above it) during this same ten day period. The only other visible planet, Mars, was in the opposite portion of the sky in February of (historical) 7 B.C. and located close to Aldebaran in Taurus. The unknown Neptune was a little further east near the head of Orion. The Moon was at new phase on or about February 2nd and March 4th. I would have to do further research to confirm what dates the Roman authorities would have placed on the calendar on these dates -- the astronomy program simply assumes the Julian calendar extends back through all of B.C. time. Year designations and month designations of course were changing regularly as Julius and Augustus Caesar claimed months and I don't know exactly what years the Romans added leap year days to February. Their calendar proved to have too many of them and we had to remove ten or eleven days and alter the system to the Gregorian calendar in the 16th (Europe) and 18th (Britain and colonies) centuries. Some applications of the Russian calendar have yet to adopt the new dating system and so they are now 13 days behind.

Of course the Jewish people had their own calendar and from my calculation, with a new moon around Sept 8 of 9 B.C. marking the seventh month, the year 8 B.C. likely had the added second Adar (the Jewish calendar has to add a thirteenth month every so often (seven times each 19 years) so that Passover falls at the right time), and this second Adar probably started on March 4th of this particular year, as I have related this timetable. So the date February 13 in the Jewish calendar was about the 9th or 10th of First Adar. Passover was still two months away rather than one full moon removed if that is so (and I believe it is otherwise Passover would have fallen quite early in mid-March).

It is interesting that our celebration of Valentine's Day is actually very close to this apparent real date of the birth of Jesus, and Christmas as we know it is thus an adaptation of the pagan rites of Saturnalia combined with European observances of the winter solstice, and I would say, combined somewhat with the Jewish festival of Hannukah which always falls in the vicinity of Christmas.

This true birth date also means that the second millenium should have fallen in the year 1994 if you accept that astronomical dating systems are the better foundation for jumping ahead two thousand years. I am not much of a medieval historian and would leave it to somebody else to comment on what if anything is significant about the year 994.

So if we had known this in the sixth century and that monk had done his calculations correctly, it could well be that this expiring year would have been 2020 A.D. and perhaps the medieval practice of starting the year with March would have persisted, so that it's conceivable that Christmas would have fallen on February 13 (or some nearby date) of 2020, and then it would be New Years Eve leading into 2021 on February 29th which is going to be March 1st of 2015. Confused? Merry Christmas and Happy New Year.

What do you think, anything to this allegory or just a vast coincidence?

Rough diagram of what I see on my skyglobe program for Feb 13, 7 B.C. astronomical time, noon Jerusalem time:

o Merc

8 Jup/ven -- O (SUN)

o Sat

o Uranus

elecktras weather bomb · 22-12-2014 8:43pm

Have you been on the sherry MT? I wont even pretend I know what that's all about. interesting read though . well done. brain tease to ponder on. cheers

The One Doctor · 22-12-2014 8:57pm

elecktras weather bomb wrote: »

Have you been on the sherry MT? I wont even pretend I know what that's all about. interesting read though . well done. brain tease to ponder on. cheers

Don't be silly, MT's towering intellect is fuelled by good beer, not sherry.

hotwhiskey · 22-12-2014 9:27pm

My theory that the Biblical narrative is allegory can be explained as follows. Venus is clearly an allegory for Mary, the mother of Jesus. Jupiter could be seen as an allegory for Jesus and/or for God. However, the ancients did not necessarily know that Uranus existed (they may have done so as that planet can be seen in very clear dark skies by people with good vision, and it's possible that knowledge of it was lost in the Dark Ages). This comment is relevant because I theorize that the three wise men did not physically exist, but were allegories for the three planets following along behind this unseen event in the solar glare. Alternatively, Jupiter could be one of the three wise men and Saturn and Mercury, known and quite visible in the dark skies of antiquity, were the other two. Gold, frankincense and myrrh could be allegories for their appearances or significances. (Jupiter is clearly the best choice for gold).

Sorry MT I have to disagree with your theory here. We know that the magi were wise men from "the East," most likely Persia, or modern-day Iran. This means the wise men traveled 800 to 900 miles to see the Jesus.
The Bible does not say that any kings or camels visited young Jesus. It does say wise men. The Bible simply mentions three costly gifts they presented—gold, frankincense and myrrh, but this does not necessarily indicate the number of men. It could of been 2 or 22. Also, the wise men clearly did not visit Jesus when he was still lying in the manger. The magi did not arrive until sometime after Christ’s presentation in the Temple in Jerusalem (Luke 2:22-39). At this time, Scripture calls Jesus a “child,” not a “baby.” It is possible that little Jesus was walking and talking by then. Jesus could been two years old.

I agree with you on time frame when Jesus was born. One problem with December is that it would be unusual for shepherds to be in fields this time of year when fields were unproductive. The normal practice was to keep the flocks in the fields from Spring to Autumn. So my own assumption thats time when Jesus was born.

Calibos · 22-12-2014 9:43pm

I'll leave it to others to state the obvious.

vistafinder · 22-12-2014 9:51pm

Its the snow!:D

Sorry MT

M.T. Cranium · 23-12-2014 8:34am

Of course people are quite free to believe what they want about the Christmas story, many or at least some might simply not believe any of it. My discussion is aimed at those who do believe but have either questions or doubts about the literal story of a guiding star.

I hope nobody was put off by my mention of astrologers, that was simply a factual statement as the science of astronomy and the practice of astrology were much closer to being the same thing then, as opposed to two entirely different practices in the post-Enlightenment era. All I meant there was that the savants who followed the movement of the planets against the fixed star background would have had the knowledge required to understand what was hidden in the solar glare.

Any rudimentary knowledge of astronomy will cast doubt on a literal explanation, that a star came to rest in the sky, although I don't mean to imply that God is incapable of miraculous powers. But a more apparent explanation that has been explored by the "ancient astronaut" crowd (of which I am not an adherent, by the way, at least not as I've heard it described), would be that intelligent beings (angels to us) arranged for this light to shine and also for the other manifestations.

My theory simply goes from any literal explanation to an allegory. The Bible is full of allegories and I personally don't consider it bad faith to look for allegorical meanings rather than literal ones when it comes to mysteries.

So this theory offers one possible interpretation of the allegory that gives a very plausible birth date for Jesus. It may not be right, some other allegory may be correct. There was another Venus-Jupiter conjunctions that people could see in the sky in the two years after the one I have mentioned. As to the timing of the visit of however many wise men, that would not conflict because they would have known in advance when the event would take place so they could have set out in whatever amount of time they needed. I am ambivalent about the literal or figurative nature of the three wise men. The real gift after all was not what they gave Jesus but what He gave all of us.

(group hug)

DOCARCH · 23-12-2014 8:51am

Fascinating stuff MT. Not a hint of heresy. Only joking! :P

It is well known that the early Christians (cleverly) 'turned' pagan festivals/rituals to Christian festivals/rituals. Christianity, in many ways, was designed to fit. I don't think even the most zealous theologian would/could argue that Jesus was born on December 25th.

Oneiric 3 · 23-12-2014 10:45am

Probably a bit away from the general theme M.T, but would there be a possible astronomical explanation for the three hours of darkness that is said to have occurred just before his death? I have sometimes wondered if this particular event was more of a metaphoric addition to the story rather than something that may have been rooted in fact.

_Brian · 23-12-2014 10:57am

M.T. Cranium wrote: »

To amplify on the widely discussed point of Christmas adopting the rituals of Saturnalia and other non-Christian winter solstice festivals, it is my belief that Jesus was born around the end of what is now February in the year 7 B.C. (or 6 B.C.E. if that includes a year zero A.D.) and here's my rationale for this.

As is fairly widely known, Jesus was not born in the year 1 B.C. or as some might style it, 0 A.D., that error was introduced by a sixth-century monk in calculating the dates for the new numbering system that was to replace the old Roman custom of numbering years from the founding of Rome, or the Jewish system which dates back almost four thousand years before Christ. We know this because Herod died in 4 B.C. and he was actively searching for the newborn infant Jesus for two years. This makes the most likely date around 6 or 7 B.C. -- further obscurity is introduced by the fact that most historians use a numbering system that goes directly from 1 B.C. to 1 A.D. whereas most astronomers use a system that includes a year never actually observed by anyone at the time, 0 (zero) A.D. -- if you look in a table of astronomical data you will find dates in that year but if you do, you need to realize that it is the same year that a historian would call 1 B.C. That means that an astronomical event in 6 B.C. would take place in 7 B.C. historical time.

Now, what happened in that year to attract my attention? I believe that the mystery of the guiding star and the three wise men may be an allegory for an event that only trained astrologers (the ancient astronomers) would have known about in those times. The two brightest planets, Venus and Jupiter, made a very close conjunction in the post-sunset sky in February of (astronomical) 6 B.C. or historical 7 B.C. Their closest approach was on February 13 during the daylight hours (Jerusalem time). Observers would not have seen this because the two planets were so close to the Sun, but trained astrologers would have known where they were. Somewhat further away from the Sun, the planets Uranus, Saturn and Mercury were all in the general vicinity.

My theory that the Biblical narrative is allegory can be explained as follows. Venus is clearly an allegory for Mary, the mother of Jesus. Jupiter could be seen as an allegory for Jesus and/or for God. However, the ancients did not necessarily know that Uranus existed (they may have done so as that planet can be seen in very clear dark skies by people with good vision, and it's possible that knowledge of it was lost in the Dark Ages). This comment is relevant because I theorize that the three wise men did not physically exist, but were allegories for the three planets following along behind this unseen event in the solar glare. Alternatively, Jupiter could be one of the three wise men and Saturn and Mercury, known and quite visible in the dark skies of antiquity, were the other two. Gold, frankincense and myrrh could be allegories for their appearances or significances. (Jupiter is clearly the best choice for gold).

Now, all of these planets were setting just after the Sun, hence the concept of westward procession. The idea that this mysterious light appeared in the time when shepherds were in their fields (tending to newborn lambs) would be a better fit for February than December also. Weather conditions in the Judean high country at that time of year can often be relatively bland, suitable for staying outdoors with a bit of protection from the chill. Is this a bit earlier than some might expect the event? Not by more than a year and there is already considerable uncertainty within a range of several years. How about the part of the story where the "star" comes to rest over Bethlehem? That part may be an embellishment of the narrative and not meant to signify anything.

There is even a hint of this narrative in the subsequent story that Jesus was recognized in the temple by two elders, one of whom was eighty-four years in age (a very advanced age in those times). The period of the planet Uranus is exactly that, 84 years. And the part where Jesus was twelve years old, more or less the period of Jupiter which is 11.86 years. Does this mean I think the entire story is allegorical? No, I believe Jesus was a real historical figure but that these birth and childhood narratives took on allegorical meanings for effect. This is not to say that three savants from a distant location did not undertake a journey to Bethlehem to salute the newborn child, but they would have known about the significance of Bethlehem (and more generally the Jerusalem area) from the Old Testament prophecies of where the Messiah would originate.

My source for all the astronomical data is the Skyglobe program. This is actually shown in historical rather than astronomical dates, there is no zero (0) A.D. in the program. Running it ahead a few days, Jupiter and Uranus converged as they both passed behind the Sun on February 21st, meanwhile Venus which was emerging from its own passage behind the Sun in that January was passing close to Saturn on February 23rd. It probably became visible as an evening star to keen observers by mid-March, Jupiter appeared in the morning skies by April of that year. Mercury was heading in front of the Sun (and considerably above it) during this same ten day period. The only other visible planet, Mars, was in the opposite portion of the sky in February of (historical) 7 B.C. and located close to Aldebaran in Taurus. The unknown Neptune was a little further east near the head of Orion. The Moon was at new phase on or about February 2nd and March 4th. I would have to do further research to confirm what dates the Roman authorities would have placed on the calendar on these dates -- the astronomy program simply assumes the Julian calendar extends back through all of B.C. time. Year designations and month designations of course were changing regularly as Julius and Augustus Caesar claimed months and I don't know exactly what years the Romans added leap year days to February. Their calendar proved to have too many of them and we had to remove ten or eleven days and alter the system to the Gregorian calendar in the 16th (Europe) and 18th (Britain and colonies) centuries. Some applications of the Russian calendar have yet to adopt the new dating system and so they are now 13 days behind.

Of course the Jewish people had their own calendar and from my calculation, with a new moon around Sept 8 of 9 B.C. marking the seventh month, the year 8 B.C. likely had the added second Adar (the Jewish calendar has to add a thirteenth month every so often (seven times each 19 years) so that Passover falls at the right time), and this second Adar probably started on March 4th of this particular year, as I have related this timetable. So the date February 13 in the Jewish calendar was about the 9th or 10th of First Adar. Passover was still two months away rather than one full moon removed if that is so (and I believe it is otherwise Passover would have fallen quite early in mid-March).

It is interesting that our celebration of Valentine's Day is actually very close to this apparent real date of the birth of Jesus, and Christmas as we know it is thus an adaptation of the pagan rites of Saturnalia combined with European observances of the winter solstice, and I would say, combined somewhat with the Jewish festival of Hannukah which always falls in the vicinity of Christmas.

This true birth date also means that the second millenium should have fallen in the year 1994 if you accept that astronomical dating systems are the better foundation for jumping ahead two thousand years. I am not much of a medieval historian and would leave it to somebody else to comment on what if anything is significant about the year 994.

So if we had known this in the sixth century and that monk had done his calculations correctly, it could well be that this expiring year would have been 2020 A.D. and perhaps the medieval practice of starting the year with March would have persisted, so that it's conceivable that Christmas would have fallen on February 13 (or some nearby date) of 2020, and then it would be New Years Eve leading into 2021 on February 29th which is going to be March 1st of 2015. Confused? Merry Christmas and Happy New Year.

What do you think, anything to this allegory or just a vast coincidence?

Rough diagram of what I see on my skyglobe program for Feb 13, 7 B.C. astronomical time, noon Jerusalem time:

o Merc
8 Jup/ven -- O (SUN)
o Sat
o Uranus

I can't claim to fully understand it but I like the explanation.

I think that as you eluded above that there are actual events that have been embellished over the years to bring us to where we are now with modern beliefs of the Christmas and other religious stories.
Thanks for the effort in putting this together.

Rikand · 23-12-2014 11:10am

Oneiric 3 wrote: »

Probably a bit away from the general theme M.T, but would there be a possible astronomical explanation for the three hours of darkness that is said to have occurred just before his death? I have sometimes wondered if this particular event was more of a metaphoric addition to the story rather than something that may have been rooted in fact.

Maybe change 3 hours to 3 minutes and pick from this list ?

http://en.wikipedia.org/wiki/List_of_solar_eclipses_in_the_1st_century
Assuming he was in his early-mid 30's when he died and assuming his date of birth was approximately 6 BC as declared by MT, here's 2 decent candidates for solar eclipses in the general area

http://tools.wmflabs.org/geohack/geohack.php?pagename=List_of_solar_eclipses_in_the_1st_century&params=25.5_N_50.8_E_

http://tools.wmflabs.org/geohack/geohack.php?pagename=List_of_solar_eclipses_in_the_1st_century&params=22.5_N_62.4_E_

M.T. Cranium · 24-12-2014 12:20am

But the crucifixion took place at Passover which falls on the full moon by the defined structure of the Jewish calendar. Hence no total eclipse of the Sun could have been a reason although three hours of course is far too long for that to be the explanation anyway.

If it is not metaphorical in terms of the mood of the shattered believers in attendance, then some entirely non-astronomical reason must be found. It's not something that I feel requires much explanation in any case, but unusual daytime darkness can be caused by smoke or dust in the air. If it was not just a metaphorical recollection (these accounts were penned months or years later) then it might just be a reference to the sort of weather on the day and not meant literally.

By the way, the two most widely accepted dates in Biblical scholarship for this event were in early April of 30 or 33 B.C., the second one is preferred, but this is based on very little more than a set of assumptions about age, length of ministry and what little is known of the career of Pontius Pilate. If we do believe this was a real occurrence, all we could really say with much certainty is that it apparently happened at the Passover in a year between 26 and 40 A.D. and even that much is not certain.

The fact that Jesus could have been born six or seven years before the A.D. calendar began simply means that whatever assumption you make about his age produces that much of a shift in the date you might expect for the crucifixion.

tomcosgrave · 24-12-2014 1:08am

MT, think the only thing that matters in relation to your theory is the following question -
- But was there any snow?!

M.T. Cranium · 24-12-2014 4:10am

No but the GFS was a bit wonky. This is why only three wise men arrived, about ten set out.

was going to post this, somewhat off topic but as people seem interested in the skies of antiquity ...

It occurred to me that some readers might acquire a downloaded version of this Skyglobe program so they can recreate the night sky for any date (or location on earth from an extensive menu) between 30,000 B.C. and 30,000 A.D.

If you use the skyglobe program, you'll find that its artificial system of calendar time starts to make no sense at all back before 4,000 B.C. or thereabouts.

They have it set up to show the sky all the way back to 30,000 B.C. but on the Julian calendar. This means that each two thousand years you go back, there are about 15 extra days. The position of the Sun on 21 December or 21 June should be roughly at its lowest then highest positions (give or take a day or two) but in fact, the winter solstice as shown on the program is 6 Jan of 2000 B.C., then 21 Jan of 4000 B.C., and so on until it gets to 21 June of 24,000 B.C.

The point is that nobody was trying to use a Roman (Julian or Gregorian) calendar much earlier than a few hundred years back into this period, so the entire thing is theoretical and somewhat misleading if you use the program to see what the sky looked like in the "spring" or "autumn" etc of some very distant year in the past. To do that you would need to assess how the Sun's progress through the sky was going in the time you had selected and work out when winter, spring, summer and autumn (n.h. or s.h.) would have been more or less ignoring the calendar dates provided. As to how historians or astronomers work when they cite very early dates in human history, I assume they use this Julian calendar and are either oblivious to its problems (which are not large enough to worry them too much if we're talking about recorded history), or else they adjust to the calendar that would have existed had there been a Gregorian calendar in place.

For example, if I read about a solar eclipse in January of 3071 B.C. (a fictitious example, by the way), was it in the January that exists in the Julian calendar, or in the projected Gregorian calendar. Back that far, let's say you read that it was on 2 January 3071 B.C. then look on this program, you might find it exactly there, or you might find it somewhere around 12 December 3072 B.C. because that's what the date would have been in our frame of reference.

Another thing you would notice, and this is not an artificial construct but the reality of the precession of our planetary axis of rotation, the high and low points of the orbits of the Sun, Moon and moving planets (a relative concept to be sure) move around in a leisurely circle against the fixed star background. In our own times, these high and low points just happen to occur when the ecliptic plane crosses the galactic equator. Back in Roman times, they happened to the left (east) of those locations by about 1/12 of the orbital period, so 2-3 days for the Moon, and a month for the Sun. In other words, nowadays, at the winter solstice, you are looking at the galactic centre when you look in the direction of the mid-day Sun. In Roman times, you would do that in November and the Sun would be lowest above the horizon further along its path. If you went back to about 11,600 B.C. the low winter Sun would be sitting where we now see the high June sun. So all that part of the sky containing Orion and nearby constellations would not rise nearly as high as we see them in the winter, and our early ancestors would be seeing them on summer nights. They would never have seen Sirius rise above their horizon anywhere much north of 30 deg N. Orion would have barely made it above by midnight of a "June" night (the skyglobe program calls it March 10th around that time, remember that it pushes winter forward about 7 days a millennium as you go back in time due to those extra leap year days).

So, to summarize, if you set out to look at the mid-winter night sky all the way back to 30,000 B.C., you would be seeing the fixed star backgrounds of months that are one month ahead per 2,300 years approximately. And the Skyglobe program would be calling these dates about 18 days later for each of these intervals. Thus the appearance of the Skyglobe background sky changes by about 12 days every 2,300 years (30-12). This error self-corrects with the calendar change (Gregorian to Julian going backward) so it only applies to B.C. dates relative to our time.

The program is of course fine to use going forward as the Gregorian calendar will only require very minor tweaking of Leap Year days to continue its desired correspondence of seasons to calendar dates. If they had programmed it to show Gregorian calendar dates before 1 B.C. some of the above problems or situations would not occur. From my understanding, the Gregorian calendar would work perfectly if they took out one leap year every three thousand years, that's how close it came to solving the Julian calendar problems (which arise because our solar year is 365.2422 days and the Julian calendar assumed it was 365.25 days, the Gregorian approximation is 365.2425 so 3/78 or 1/26 of the error remains and in the same direction, namely, too many leap years).

Will post some more details about what changes over these long periods. This may be ultra confusing but the main point is, sky changes slowly over time at both (a) same times of the real solar year given an accurate calendar like the Gregorian, and also (b) at similar dates in a less accurate calendar that is not absolutely fixed to the solar year. The differences could partly offset as they do in this instance.

RobertKK · 24-12-2014 11:57am

Great detail in your analysis MT, thanks for sharing it, I have to read your other posts in this topic later due to length and its detail.
Happy Christmas.

Bejubby · 24-12-2014 12:44pm

You need to write a book and buy a huge telescope from the profit you make.

Very good read.

M.T. Cranium · 24-12-2014 5:05pm

I posted this same material on another forum and received a very interesting response in the form of a lengthy history of the fixing of dates for Christmas. On first reading the general theme seems to be that it gradually fixed upon the 25th of December as much for cultural as any genuine religious reasons, but that might be an unfair assessment. There were some authorities in the early Catholic church who argued for various other dates but by the 5th century the current date was pretty much universally accepted among believers.

Perhaps unsurprisingly, these early observers gave little weight to any argument about the heart of the winter season being a poor time to be camped out in fields with flocks of sheep.

So meanwhile, I was mentioning that the Skyglobe program can show some of the slow changes in the sky over long periods of time. I was interested to see whether it had incorporated the factor of changing axial tilt. Our current axial tilt is 23.4 deg but back around the Neolithic it was more like 24 deg, a fact which had some bearing on studies of significance of old monuments since the axial tilt would determine the exact point of sunrise and sunset at the solstices.

Now I already explained that if you keep going back to 21 Dec in the program, while that should be very close to winter solstice both in our modern calendar and in the Roman calendar (remember, the Julian calendar was accurate for the Roman empire period, it just drifted out of sync gradually until the medieval era when its errors became noticeable), the Julian calendar extended backwards would place the winter solstice gradually later in the year at a rate of about 7 days per millennium.

So I took the more empirical approach of going back a thousand years at a time from 1 A.D. in my study, and then forward however many days would be required to place the rising sun on the horizon at its southernmost position for the chosen location (which was Dublin but this argument would apply anywhere in the northern hemisphere with adjustments in time of day).

Just so you could replicate my findings, I would mention that I chose the minute when the depicted sphere of the Sun on a high zoom setting was bisected by the flat horizon line, and for 2014 on 21 Dec this was shown to be 0843h and located about 41 deg south of due east, or almost southeast. I set this position to the centre of my screen and at maximum zoom this shows the designation "SE" about one-third of the distance from the rising Sun to the right side of the screen.

So it would be this appearance on screen that I searched out going back in thousand year intervals (and 13 years for the jog from 14 A.D. to 1 A.D., bearing in mind this program has no year zero A.D. and this will set to intervals of 1,000 B.C. etc going back.

If you were to do this yearly back to Roman times you would notice the jog in 1752 when the calendar changed (in America since this program originates from there) and the solstice was around 10 December, and then a gradual reset to our expectation of 21 December in the first century. You would also notice that even at maximum zoom it is difficult to distinguish from visual inspection which day in the two week period 14-28 Dec is the point of greatest southward shift of the sunrise. That being said, your precision in choosing the date is irrelevant to the premise that the location is tied to axial tilt.

So actually I am doing this for the first time as I type this up, here we go (isn't live science interesting?) ... don't answer that (yet).

Shifting the controls back from 2014 to 1 A.D. we find that the Sun is at that same position at 0847h, and shifting dates back and forth fails to depict any southward shift in the sunrise point. Going out of zoom mode you can see that the Milky Way has already risen, indicating that gradual rotation of the axis in three dimensional space. Nowadays the Sun is crossing that galactic equator at its winter solstice rising.

At 1,000 B.C. the most apparent southward displacement of sunrise is on 29 December and it appears very slightly closer to the "SE" designator. The time is given as 0859h. Now this shift is not significant unless sunset times are shifting at a different rate, so at the end of this description I will check that out, to assess whether this program has any slight issues with time of day (a construct which would only make sense if some authority fixed time of day to the rising and setting of the Sun on a fixed date such as the one I am investigating, winter solstice).

Set to Dec 2,000 B.C. the southern extreme of the sunrise is on 7 January (of 1999 B.C.) at 0854h. Once again, there is a very slight shift towards the SE.

Now I won't report on every thousand years, let's make the interval four thousand. At 5,999 B.C. the winter solstice sunrise is on 5 Feb at 0859h. The position is now quite clearly closer to the SE than in modern times. So it appears that the program has captured the change in axial tilt.

At 9,999 B.C. the relevant date and time is 9 March at 0856h. The drift towards the south is no longer obvious.

At 13,999 B.C. the relevant date and time is 4 April at 0904h. The position is unchanged from the previous noted case.

At 17,999 B.C. the depiction is 3 May at 0937h. As I go forward I start to realize why the time of day is changing. The earth's perihelion point changes slower than the shift in the polar rotation. Hence the earth is reaching these positions faster in modern times and the sunrise time given a fixed day is shifting forward as we go back in time. This will probably shift all times of day about the same amount at this time of the tilt-based year. (remember, the fixed position based year is shorter, the earth passed the same point relative to fixed space a bit earlier each year we go back, and by this point about six months earlier). Also the drift of sunrise position towards the SE has once more become apparent, it had checked up for a while now it's visibly at least one degree closer than in the current depiction.

The story remains similar back to 21,999 B.C. when the sunrise is at 10:09 on 30 May, and on 25,999 B.C. when it takes place at 10:11 on 21 June. There has been a slight shift towards the SE through this period. So now, time to check the length of day to see if this shift in sunrise time of 77 minutes is anything other than a program hiccup. The 21 Dec 2014 sunset is depicted at 3:59 p.m., and for the analogue date in 25,999 B.C. it is 5:25 p.m. That has shifted by 86 minutes. So the day was 9 minutes longer but the time frame has shifted by an average of 83 minutes. This may be just due to a projection of current length of day back into a distant time when the earth was spinning at different rates on its axis, or it might have some connection to the change in orbital distances. I checked the data for the summer solstice rising and setting times in 25,999 B.C. and they were also shifted later but by only forty mintues from today's time frame. (note the program introduces daylight savings time in the 20th century, does not show historical dates as if that existed, and I factored that in here).

So my conclusion is that the program has an accurate depiction of axial tilt changes and a built-in relatively minor time of day error that must originate from some assumptions about the standard length of a day.

As 2020 comes to a close, it's just seven weeks to Christmas

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