In an earlier posting we looked at the question of a ‘Dark Star’ or Nemesis companion:
Along the way that posting wandered past the local stellar group and who orbits whom. (One link in it is to a neat animation of the local stars. In that, Sirius is the larger bluer star a bit below and not too far from us.)
My conclusion was that most likely we orbited the local center of mass, but that things tend to move a lot and some stars are whizzing past at decent speed, so maybe ‘orbit’ isn’t the best description.
Yet I didn’t really address the root question that tickled the pondering. Might we be orbiting with a nearby star in some more stable way? And does the idea of precession “have issues” enough to make it a bit broken.
One of the major candidates for such a ‘binary companion’ is Sirius. The Dog Star. The star that makes folks ‘star struck’.
The wiki says it’s moving, but then again, that’s a wiki and subject to “consensus corruption” where new ideas go to die, murdered by the preponderance of small minds… and the excess zeal of the smallest of them.
Radial velocity (Rv) −7.6 km/s
Proper motion (μ) RA: −546.05 mas/yr
Dec.: −1223.14 mas/yr
So it’s moving toward us (or we toward it) at a little under 8 km / second. The right ascension is changing by about 1/2 arc seconds / year and the declination by about 1 1/5 arc seconds / year. Not a lot, but still not static. It also isn’t clear to me how well ‘proper motion’ is corrected for the motions of the earth ( the wiki says measured from the center of mass of the solar system) so something ‘invariant’ in our sky in terms of precession might well have a ‘proper motion’ number that looks like motion.
At the same time the stars can be observed to move slightly retrograde, at the rate of about 50 arc seconds per year, a phenomenon known as the “precession of the equinox”
As I understand it, the “proper motion” is what is left after correcting out the effects of earth movements, so that 50 arc seconds of “precession” is already removed. Which implies that viewed from earth, we ought to see that 50 arc seconds of precession in Sirius. (And, I think, some declination change as well due to things like Chandler Wobble and obliquity changes).
Which is all well and good. Except. There are other folks who say they don’t see that motion. So “Who to believe?” comes to mind.
Looking at the animation here:
It does look like a fairly uniform field of 32 ‘nearby stars’. But put your cursor over the redish ones, and you find a lot of them are fractions of a solar mass. Some down at 1/10 others at 3/10. The bulk of the mass is in Procyon and Sirius with some in Alpha Centauri (but it is cruising through pretty fast from below). So I can see a case of there being mostly offsetting masses in the dwarfs, and with a large mass for some excess attraction in the direction of the two blue ones, relatively near each other, in the Sirius group and the Procyon star. At good 3 solar masses in Sirius A/B and another 1.5 in Procyon. Total near 4.5 solar masses. Makes those ‘tenths’ sized dwarfs a bit less important.
Some folks have asserted that Sirius doesn’t precess, while other folks say it does, and that’s why the Nile Floods no longer happen just after Sirius has a Heliacal Rising. Looking into that, it is a bit harder to sort out. The old Egyptian calendar(s) are a bit complex anyway, then we have the Julian / Gregorian offsets to track…
A tablet from the reign of First Dynasty King Djer (c. 3000 BC) was conjectured by early Egyptologists to indicate that the Egyptians had already established a link between the heliacal rising of Sirius (Egyptian Sopdet, Greek Σείριος Seirios) and the beginning of the year. However, more recent analysis of the pictorial scene on this tablet has questioned whether it actually refers to Sothis at all. Current knowledge of this period remains a matter more of speculation than of established fact.
So right off the bat, we’ve got 4 names for the same star. “Sothis”? Yup…
The Egyptians may have used a luni-solar calendar at an earlier date, with the intercalation of an extra month regulated either by the heliacal rising of Sothis or by the inundation of the fields by the Nile. The first inundation according to the calendar was observed in Egypt’s first capital, Memphis, at the same time as the heliacal rising of Sirius. The Egyptian year was divided into the three seasons of akhet (Inundation), peret (Growth – Winter) and shemu (Harvest – Summer).
The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). The difference between a seasonal year and a civil year was therefore 365 days in 1,460 years, or one day in four years. Similarly, the Egyptians were aware that 309 lunations nearly equaled 9,125 days, or 25 Egyptian years, which was later used in the construction of a secondary lunar calendar that did not depend on observations
And we’ve got some lousy leap year handling and we’ve got at least 3 different calendars. (Lunar, Agricultural, and Heliacal) The Agricultural being based on the inundation.
It goes downhill from there, as we’ve got the Romans coming in and mucking about. Making changes. Adding a leap year, then Augustus introduces the Alexandrian calendar…
Ptolemaic and Roman
According to Roman writer Censorinus, the Egyptian New Year’s Day fell on July 20 in the Julian Calendar in 139 CE, which was a heliacal rising of Sirius in Egypt. From this it is possible to calculate that the previous occasion on which this occurred was 1322 BC, and the one before that was 2782 BCE. This latter date has been postulated as the time when the calendar was invented, but Djer’s reign preceded that date.
In 238 BCE, the Ptolemaic rulers decreed that every 4th year should be 366 days long rather than 365. The Egyptians, most of whom were farmers, did not accept the reform, as it was the agricultural seasons that made up their year. The reform eventually went into effect with the introduction of the “Alexandrian calendar” by Augustus in 26/25 BCE, which included a 6th epagomenal day for the first time in 22 BCE. This almost stopped the movement of the first day of the year, 1 Thoth, relative to the seasons, leaving it on 29 August in the Julian calendar except in the year before a Julian leap year, when a 6th epagomenal day occurred on 29 August, shifting 1 Thoth to 30 August.
It continues on from there with even more updates and changes. The “reformed” calendar… But we do get one useful bit here. That in 139 AD we had a Sirius rising on July 20th. Julian Calendar. So how to align that with today and compare it to the expected precession? Now Sirius rises on about August 1st to 3rd (it depends on where you are at):
Latitude HR Date 38 8/9/2010 37 8/8/2010 36 8/7/2010 35 8/6/2010 34 8/5/2010 33 8/4/2010 32 8/3/2010 31 8/2/2010 30 8/2/2010 29 8/1/2010
So what latitude is Egypt? Well, we need to pick one… The wiki for Cairo says it is at 30 degrees N, so August 2nd. But that’s in Gregorian time… Which has some offset from Julian.
Realignment of the year
The first step of the reform was to realign the start of the calendar year (1 January) to the tropical year by making 46 BC (708 AUC) 445 days long, compensating for the intercalations which had been missed during Caesar’s pontificate. This year had already been extended from 355 to 378 days by the insertion of a regular intercalary month in February. When Caesar decreed the reform, probably shortly after his return from the African campaign in late Quintilis (July), he added 67 more days by inserting two extraordinary intercalary months between November and December.
These months are called Intercalaris Prior and Intercalaris Posterior in letters of Cicero written at the time; there is no basis for the statement sometimes seen that they were called “Undecimber” and “Duodecimber”. Their individual lengths are unknown, as is the position of the Nones and Ides within them.
Because 46 BC was the last of a series of irregular years, this extra-long year was, and is, referred to as the “last year of confusion”. The new calendar began operation after the realignment had been completed, in 45 BC.
So a lot of this comes down to just how good you think that Julian “fix” was… But by a bit short of 200 years later, it ought to have been off by a fractional day. The wiki goes on at some length from there, as the months got the numbers of days shifted a bit, and the exact timing of the ‘leap day’ wandered, and some more.
Yet we’ve got ‘on the order of’ 12 days of drift from about July 20 to August 2 or 3.
Precession is a little bit variable, but runs about 26,000 years, so would give about 26 degrees of precession by now. At 365 days / 360 degrees in a one year rotation, that ends up about 26 days ( IFF I’ve not screwed something up somewhere).
Gee, 26 days is different from 12 days. Not enough to say flat out “we orbit it”, but enough to say that there’s an issue with simple precession and there’s at least a partial orbital motion going on. As a first ‘sanity check’ measure, it says there’s something happening.
Are there any other lines of evidence for Sirius not being on a nice regular precession?
The Sothic cycle or Canicular period is a period of 1,461 ancient Egyptian years (of 365 days each) or 1,460 Julian years (averaging 365.25 days each). During a Sothic cycle, the 365-day year loses enough time that the start of the year once again coincides with the heliacal rising of the star Sirius (the Latinized name for Greek Σείριος, a star called Sopdet by the Egyptians, in Greek transcribed as Sothis; a single year between heliacal risings of Sothis is a Sothic year). This rising occurred within a month or so of the beginning of the Nile flood, and was a matter of primary importance to this agricultural society. It is believed that Ancient Egyptians followed both a 365-day civil calendar and a lunar religious calendar.
So they had ‘calendar drift’ relative to the Agricultural calendar, which was set via Sirius rising and the floods. We are looking for just what date, more or less, inundation came then, and comes now (and has it changed?)
The ancient Egyptian civil year was 365 days long, and apparently did not have any intercalary days added to keep it in alignment with the Sothic year, a kind of sidereal year. Normally, a sidereal year is considered to be 365.25636 days long, but that only applies to stars on the ecliptic, or the apparent path of the Sun. Because Sirius lies ~40˚ below the ecliptic, the wobbling of the celestial equator and hence of the horizon at the latitude of Egypt, as well as the proper motion of the star, causes the Sothic year to be slightly smaller. Indeed, it is almost exactly 365.25 days long, the average number of days in a Julian year.
OK… so we have a stellar year that’s just about perfectly matched to the solar year. I’m not quite seeing how the wobble of the axis can make an orbit shorter or longer by any but a trivial amount, and certainly not over 2000 years or so…
This cycle was first noticed by Eduard Meyer in 1904, who then carefully combed known Egyptian inscriptions and written materials to find any mention of the calendar dates when Sirius rose. He found six of them, on which the dates of much of the conventional Egyptian chronology are based. A heliacal rise of Sirius was recorded by Censorinus as having happened on the Egyptian New Year’s Day, between AD 139 and 142. The record actually refers to July 21 of 140 AD but is astronomically calculated as a definite July 20 of 139 AD. This correlates the Egyptian calendar to the Julian calendar. Leap day occurs in 140 AD, and so the new year, Thoth 1, is July 20 in 139 AD but it is July 19 in 140-142 AD. Thus he was able to compare the day on which Sothis rose in the Egyptian calendar to the day on which Sothis ought to have risen in the Julian calendar, count the number of intercalary days needed, and determine how many years were between the beginning of a cycle and the observation. One also needs to know the place of observation, since the latitude of the observation changes the day when the heliacal rising of Sirius occurs, and mislocating an observation can potentially change the resulting chronology by several decades. Meyer concluded from an ivory tablet from the reign of Djer that the Egyptian civil calendar was created in 4241 BC, a date that appears in a number of old books. But research and discoveries have since shown that the first dynasty of Egypt did not begin before c.3100 BC, and the claim that 4241 BC (July 19) is the “earliest fixed date” has since been discredited. Most scholars either move the observation upon which he based this forward by one cycle of Sothis to 2781 (July 19), or reject the assumption that the document in question indicates a rise of Sothis at all
Okay… starting to sound like a bit of a mess to me. We’ve got what looks like a lack of precession, some handwaving, and then a lot of jiggling the Egyptian dates to place history…
But there is this gem:
It has been noticed, and the Sothic cycle confirms, that Sirius does not move retrograde across the sky like other stars, a phenomenon widely known as the precession of the equinox. As prof. Jed Buchwald has pointed “Sirius remains about the same distance from the equinoxes — and so from the solstices — throughout these many centuries, despite precession.” For the same reason, the helical rising (or zenith) of Sirius does not slip through the calendar (at the precession rate of about one day per 71.6 years), as other stars do. This remarkable stability within the solar year may be one reason that the Egyptians used it as a basis for their calendar whereas no other star would have sufficed.
The lunisolar theory of precession requires that the earth wobble enough to lose one complete rotation on its axis and one revolution around the sun (relative to the fixed stars) per precession cycle. Modern astronomers now measure the rate of precession via radio telescopes fixed on distant quasars and a process known as Very Long Baseline Interferometry (VLBI) confirms the earth changes orientation to the stars at about 50.3 arc seconds p/y, equating to one complete precession of the equinox in about 25,700 years. Nonetheless, Sirius, due to its proper motion, remains practically stationary making it the ideal marker for ancient Egyptian planning purposes.
Now how in the heck do you get a star moving at just exactly the same rate as precession, but relative to all the other stars, and not relative to the earth, where precession is supposedly centered? I’m just not seeing how that can happen. For a star, several light years away, to hold still while we shift, it must be moving tangentially rather fast, and, somehow, the N/S motion must cancel the change in relative ’tilt’ of the earth on both the ‘departure’ and ‘return’ parts of the precession. ( i.e. it’s not just the equatorial E/W shift that must cancel, but also the N/S polar shift as the tilted pole wanders). Something seems fishy…
Finds more suspicious things. Like orbital resonances in the outer planets. (Hey, even if they are now called dwarf planets, that’s still a planet…)
Celestial bodies in our Solar System show harmonic resonance with the Sirius system. Pluto and Sedna are at an incline to the plane of the solar system of roughly 17°, the same as Sirius. Both have orbital periods of 250 years and 12,000 years, which are at 1:5 and 1:2 resonances with Sirius, respectively (12,000 years is roughly one half of the orbit of the Sun around Sirius, hence a 1:2 resonance).
Resonance is a criterion stipulated for any system of orbiting bodies, which is why planets and moons are often times tidally locked with their parent body, and is another reason why the hypothesis of a putative wobble is very unappealing. A wobble is indicative of dynamic instability, not harmonic resonance (think of a spinning top before it falls, it begins to wobble).
Sirius is a binary system. Sirius A is the highly visible star, but there is a companion known as Sirius B, first described in modern times by the Dogon tribe of Mali (Africa) and subsequently verified by the observational science of astronomers. The Dogon also described a third celestial body with characteristics of a neutron star. While a neutron wouldn’t be visible in the same manner as Sirius B, the combined gravitational attraction of a neutron star, a white giant star and a white dwarf would certainly provide the gravitational force needed to keep the Sun bound at a distance of 8.6 light years. In fact, the presence of a neutron star is by no means necessary for the gravitational interaction of the Sun with Sirius.
It goes on to assert that a shaft in the Great Pyramid is aimed right at Sirius and so it must have been stable for thousands of years. And more…
This information by itself raises serious questions about the validity of the “Wobble Hypothesis”. However the major flaw of this hypothesis comes from an examination of the static position of the star Sirius in relation to precession and its historical utilization as a marker for time in the Sothic Calendar of the Egyptians.
From Africa, where the Dogons live, the star Sirius disappears below the horizon and is out of sight for a couple of months; then it appears again on the morning of July 23, when it rises about one minute before the Sun. It appears bright ruby-red, just above the horizon, almost exactly due east. Sixty seconds later the Sun emerges. So you can see Sirius for just a moment, then it’s gone. This is called the helical rising of Sirius, which was a very important moment for most of the ancient world, not just for the Dogons and Egypt.
This is the moment when Sirius and the Sun and the Earth are in a straight line across space. In Egypt, almost all the temples were aligned with this line, including the gaze of the Sphinx. Many of the temples had a tiny hole in the wall somewhere; then there would be another wall and another, going into some dim inner chamber. In that chamber there would be something like a cube or Golden Mean rectangle of granite sitting in the middle of the room with a little mark on it. At the moment of the heliacal rising of Sirius, a ruby-red light would strike the altar for a few seconds, which would begin their new year and the first day of the ancient Sothic calendar of Egypt.
The periodicity of the helical rising of Sirius was such that the Egyptians based their calendar on it [right]. Every year for millennia the appearance of Sirius coincided with the flooding of the Nile, an event that remarkably still happens to this day.
So how can we have very old buildings with a stellar pinhole projector that still works if their is precession?
Then there are some folks who have taken modern measurements:
Sirius Transit Data
[This page was updated June 19, 2012.]
Why Does Sirius Move in the Opposite Direction to Precession?
Why Does the Rate of Sirius Motion Almost Exactly Cancel Precession?
The following graph displays actual measured daily transit readings of Sirius (blue line) and compares these readings to the precession rate (red line) of the rest of the stars in the sky.
This clearly demonstrates that Sirius does not precess. The question is—why does this happen?
Mr. Homann concludes below that:
“These observations clearly indicate that the so-called ‘precession of the earth’ is NOT a scientific fact, and that the Sirius system has a noticeable gravitational influence on our solar system.”
The continuous measurement of 6 April 1994 to 5 April 2000 confirmed this fact conclusively. In that period the total negative deviation of ‘Sirius time’ from the total mean sidereal time accumulated to 4.1 seconds. This means about negative 0.68 s per year (!). Again, according to ‘precession’ a negative time difference of 6 × 3.34 s or about 20 seconds should have occurred, but did NOT occur with respect to Sirius!
We also have more orbital resonance notes:
The meridian transit measurements of Sirius have shown that neither a time difference of 6 × 1223 s, nor a difference of 6 × 3.34 s has occurred over the 6-year observation period from April 1994 to April 2000.
These observations clearly indicate that the so-called ‘precession of the earth’ is NOT a scientific fact, and that the Sirius system has a noticeable gravitational influence on our solar system. Obviously, Newton’s laws of gravitation cannot explain Einstein’s universe. In that respect, it requires further study to see if the 49 year cycle of the Sirius system can provide us with an explanation of the large fluctuations and annual irregularities in earth’s rate of rotation that have also been observed around 1941 by experts at the US Naval Observatory.
Two other phenomena should be mentioned that took place during the conjunction of Sirius A, Sirius B and the sun around the beginning of February to the end of March 1989, as the function of the time deviation entered from the negative into the positive range (see Graph 1). During this time our outermost planet Pluto, whose revolution period of 248.421 years is exactly 5.0004 to 1 in relation to the Sirius B – Sirius A’s orbit period of 49.68 years, went through the perihelion of its very eccentric orbit. On 23 March 1989 an 800 m long ‘rock’ came in strikingly close proximity to our earth at a speed of about 70.000 km/h. Missing our earth by only a few hours – thereby sparing us a gigantic catastrophe – it also went through its perihelion between sun and Sirius. Thanks to astronomers, who discovered it as it already disappeared again into the vastness of space, a major widespread panic was avoided. These celestial phenomena are not subject to plain coincidence, but are lawful celestial mechanical events. In fact, the Sirius system determines the second (empty) focus point, which is essential for the elliptic orbits of these and other celestial bodies in our solar system. Keep in mind that even our earth has its perihelion around January 2, as it passes through the conjunction of sun and Sirius each year.
There are other pages, with similar ideas, but I think these give enough evidence.
There’s something odd about Sirius. It looks like we are at minimum gravitationally bound, and at most orbiting each other in an extended system.
Yet the last flood of the Nile was in June in 1964 as the damns were being built. June is a ways off from August, some something still isn’t quite right here. Then again, the flood depends on when it rains in Ethiopia, and perhaps that isn’t as regular as the stars and sky.
I’m still not satisfied that things are resolved enough. To many loose ends. But it’s very late, and I need to wrap this up for now. Yet it really wants a chart of just when the floods came, and when Sirius rises through the last millennium or so.
What I think is most likely is that we do co-orbit with Sirius, but a little less strictly than for a strict binary system. (Yet enough for holes in pyramids to stay aligned).
But the ancient calendars are ‘messed up’ and the modern floods have ended decades past.
Is it just a profound coincidence of the proper motion of Sirius? Perhaps, but I can’t see how…
It looks more likely that our proper motion includes a very slow orbital component, for the entire solar system, about some large mass near Sirius A / B.
Perhaps after a bit of a rest I can find more…