There has been some interesting discussions taking place recently in the page comments area that is worthy of a separate forum topic. The main issue is which point do the planets orbit. Most but not all agree that the smaller planets orbit the Sun but when it comes to the Gas Giants there is some division. I think all the planets orbit the Sun but would be extremely happy if it can be proved that the Gas Giants orbit the SSB. Hopefully we can work through the details and come to some conclusions. The objective is to produce graphs, facts etc and not amble on with nothing more than rhetoric. It will be assumed that the JPL data is correct.
Howard and maybe Steve are thinking the Earth orbits the SSB. Lets take a look at a graph produced from JPL data that shows the Earth/Moon Barycentre (EMB) distance from the SUN and SSB. Click on the pic for a larger view.
Note: The referenced Wikipedia distance figures, Aphelion 152,098,232 km Perihelion 147,098,290 km
I can make the spreadsheet available if interested which shows a date range of 1800-2040. What can be seen is the EMB/Sun distance is very stable with fluctuations mainly due to the elliptical orbit. If you look closely there is a smaller fluctuation of about 15000 km's in the aphelion and perihelion distances caused by planet perturbations. The SSB distance is fluctuating over a much greater range, the SSB distance is influenced by the Gas giants and their influence on moving the Sun from the SSB. 1817 is a good point to look at the planet positions.
The position of N/U/J moving the Sun closer to the Earth assuming the Earth doesn't move (hypothetical), the position of the outer planets relative to the perihelion the controlling factor. The amount of variation on the SSB is far more extreme and if the Earth did orbit the SSB there would be many repercussions. The short term climate changes would be severe, the many indices that are recorded like isotopes, F10.7, flux, EUV, TSI, diameter size of the Sun etc etc would have to allow for this fluctuation along with the repositioning of satellites.
I think the solar diameter measurement might be good place to start and will see if I can find some papers on it, but the elephant in the room is that if the Earth has the SSB as an orbit axis point why is there so much fluctuation?
One of the downsides of running the Dupral system is the ability of contributors to delete their comments. Both Howard and steve's comments have disappeared, but I have restored them from the way back machine.
Thanks steve for the link to the Universe Sandbox, its a nice piece of software although I am not sure I have the hardware to run it properly. I have to reduce my screen size to stop it blanking out.
To clarify your graphs above... the planet-Sol distance is being subtracted from the planet-SSB distance, correct? So a positive value means that the SSB is between Sol and the planet.
No, I am subtracting the planet/SSB distance from the planet/Sun distance, but yes a positive value means the SSB is between Sol and the planet.
I was under the impression that the SSB is always either between Sol and Jupiter or equidistant, on account of Jupiter's mass contributing so much to the SSB calculation. But it looks like there are occasions on the 178 year interval where enough mass lines up on the other side that Sol comes ever so slightly between the SSB and Jupiter.
Yes, and this is what Landscheidt described as zero crossings which he used to predict grand minimia. Zero crossings happen near the time of grand minima as they require Uranus & Neptune to be together, but thanks to Carl's graph today we can see the AM perturbations are where the action is.
The swiss ephemeris looks interesting as it may allow AM graphs in the future to cover 10,800 yrs instead of the 6000 yrs covered by DE405/406. This would be useful for comparing AMP events further back in the Holocene. We just need it be be made public and accessible like JPL. JPL claim 25 metre accuracy for the outer planets which is backed up by observations so I am of the opinion the axis point is hidden in the data. In the background if my memory serves me correctly there is a planet perturbations program that is part of DE405/406 that is constantly being refined by observations. But Neptune is a long way away and I have noticed from reading old papers that ephemeris files created before DE405 lacked sufficient accuracy for the outer planets. I am at a loss why the original Neptune distance graph shows the 13 year 1.5 million km modulation while Uranus and Saturn do not.
I referenced this paper HERE to Howard that quantifies the JPL data but think it bears repeating here, this excerpt in particular gives me some confidence: