Comments on: Statistician debunks Gore’s climate linkage to the collapse of the Mayan civilisation

By: Carsten Arnholm, Norway

Carsten Arnholm, Norway — Sat, 13 Dec 2008 14:58:57 +0000

Thanks, Leif. I will give it a good study….

By: Leif Svalgaard

Leif Svalgaard — Sat, 13 Dec 2008 09:32:53 +0000

you can see the 1/2 year period of the diminished difference between center and shell… ===>
you can see the 1/2 year period of the difference between a circular and an eccentric orbit.

By: Leif Svalgaard

Leif Svalgaard — Sat, 13 Dec 2008 09:27:47 +0000

Carsten Arnholm, Norway (11:43:37) :
“This is much too large. Try again. I think the influence of Jupiter is 2251 km = 0.00586 lunar distances with a period of 398.9 days, or ~100 times smaller than what you have.”
Do you have a reference to support this value?

Do I need one? :-)
The standard reference is JPL’s ephemeris calculator that we have referred to earlier, but here is it again: http://ssd.jpl.nasa.gov/?horizons.

Here http://www.leif.org/research/Earth%20Orbit%201990-2008.pdf is plot of the distance between the Center of the Sun and the Center of the Earth. This distance is the one seen by a solar photon [emitted ~8 minutes before observed at Earth] that makes up TSI. The data is for 1990-present and the X-axis is in days. Distance is plotted in AU.
In the second plot I show the result of subtracting a perfect sine wave with a period of precisely one year. This makes any deviations caused by other bodies easier to see. In particular, you can see the 1/2 year period of the diminished difference between center and shell…
In the third plot I show the FFT power spectrum for the difference. Because the strictly one-year period has been removed, there is a sharp dip right at 1 year. [frequency 0.0027278]. And a 1/2 year period has been introduced. You can also see the synodic periods of other bodies as indicated by the arrows, in particularly the largest effect due to the Moon, and the second largest due to Jupiter [power = 0.00001505 AU = 2251 km].

By: Carsten Arnholm, Norway

Carsten Arnholm, Norway — Fri, 12 Dec 2008 19:43:37 +0000

Leif Svalgaard (07:40:27) :

This is much too large. Try again. I think the influence of Jupiter is 2251 km = 0.00586 lunar distances with a period of 398.9 days, or ~100 times smaller than what you have.

Do you have a reference to support this value? I agree on the period roughly, but 2251 km appears to be a very small value indeed. It sounds like the perturbations caused by the Moon?

I am playing with some close encounters of asteroids that seem to work reasonably well, so … a reference would be of interest.

By: lgl

lgl — Fri, 12 Dec 2008 18:57:27 +0000

Because when decelerating the friction will decrease the speed of the outer part.
When accelerating the friction will pull on the outer part so it will not drag behind as much as it otherwise would do. I’m of course talking about friction between the water and the bowl. I you mean it would not work without friction between the bowl and the plate you are of course right, but that’s not relevant, the setup is just a way to simulate the system.
So you still do not agree the water will start circulating? How can that be avoided when the tangential speed of the outer rim is much higher the that of the inner when you stop the rotation? Do the experiment and see for yourself.

By: Leif Svalgaard

Leif Svalgaard — Fri, 12 Dec 2008 17:24:07 +0000

lgl (05:49:17) :
And this is not caused by friction. Without friction the effect would be even bigger.
Without friction none of these spin tables would work. So describe why the lack of friction would make the effect bigger.

By: Leif Svalgaard

Leif Svalgaard — Fri, 12 Dec 2008 15:40:27 +0000

Carsten Arnholm, Norway (15:52:21) :
By my own revised estimates (to be taken with some skepticism) it amounts to about 2/3 Lunar distance (relative to a perfect ellipse) and with a period just over a year.
This is much too large. Try again. I think the influence of Jupiter is 2251 km = 0.00586 lunar distances with a period of 398.9 days, or ~100 times smaller than what you have.

By: lgl

lgl — Fri, 12 Dec 2008 13:49:17 +0000

Leif,
Yes, unlike you I didn’t conclude how everything works decades ago.
“So if I slow the rotation a bit, the outer parts will speed up”
Relative to the inner parts, yes.
http://einstein.atmos.colostate.edu/~mcnoldy/spintank/
There’s even a video:
http://einstein.atmos.colostate.edu/~mcnoldy/spintank/btrop_instab.mpg
(see I even have Einstein on my team :)
And this is not caused by friction. Without friction the effect would be even bigger.
I must say I’m not sure about this when the bowl is at the center of rotation but taking one step back to the rotating plate, I’m sure you are wrong when you say “but not start the water rotating around the center of the bowl” It will.

By: Leif Svalgaard

Leif Svalgaard — Fri, 12 Dec 2008 09:57:57 +0000

lgl (14:09:30) :
since I have said radius probably is not as important as I first stated.
You surely change your mind a lot. good thing that Mother Nature doesn’t.

We can simplify even more. You have a slowly rotating bowl of water. Then you stop the rotation, and the outer parts will get a higher angular velocity than the inner parts because of its higher momentum.
So if I slow the rotation a bit, the outer parts will speed up…
Again, good that Mother Nature doesn’t know about this…

By: Carsten Arnholm, Norway

Carsten Arnholm, Norway — Thu, 11 Dec 2008 23:52:21 +0000

I can see I have missed a long thread ….

Old Coach (18:03:57) :
A fair question – one that has probably been asked before on this blog – is the following:
How much does Earth respond to the orbit of Jupiter.

I have been playing with that question. Jupiter does not generate significant tides on Earth, but it (together with Saturn++) does perturb the Earth’s orbit around the Sun. By my own revised estimates (to be taken with some skepticism) it amounts to about 2/3 Lunar distance (relative to a perfect ellipse) and with a period just over a year. But the Earth is still in free fall as i has been emphasized.

By: lgl

lgl — Thu, 11 Dec 2008 22:09:30 +0000

Leif,
In my example with the layers I didn’t say they would move in opposite directions. You, the observer, is rotating along with the inner layer (or actually revolving this time:), but one time the outer layer is moving faster than you, next time it is moving slower than you, so from your point of reference the outer layer is moving first in one then the other direction.
Your questions is not relevant anymore, since I have said radius probably is not as important as I first stated. (and your far away little star can not change the acceleration of the large star much)
We can simplify even more. You have a slowly rotating bowl of water. Then you stop the rotation, and the outer parts will get a higher angular velocity than the inner parts because of its higher momentum.

By: Leif Svalgaard

Leif Svalgaard — Thu, 11 Dec 2008 20:13:09 +0000

Leif Svalgaard (11:00:18) :
The water never begins to move back towards the center.
Disregarding gravity, of course.

By: Leif Svalgaard

Leif Svalgaard — Thu, 11 Dec 2008 20:09:14 +0000

Leif Svalgaard (22:44:33) :
I was being specific. Please respond to each point.

lgl (13:36:57) :
“Shrink the mass a bit more, stronger circulation would follow
No, acceleration would decrease. And if you removed Jupiter, Sun’s acceleration would decrease.

“Shrink the mass of one star [e.g. with a stronger stellar wind]. That would move the barycenter closer to the other star”
Agree?

“thus making the bend sharper”
Agree?

“One side of the sun is moving in a sharper bend than the other.”
Agree? [actually your own words]

“and the circulation stronger.”
Sharper bend = stronger acceleration
Agree?

“Shrink the mass a bit more”
This move the barycenter closer, hence making the bend sharper.
Agree?

“sharper bend = stronger acceleration”
Agree?

“stronger acceleration = stronger circulation”
Agree?

By: Leif Svalgaard

Leif Svalgaard — Thu, 11 Dec 2008 19:00:18 +0000

lgl (10:17:40) :
Your example with the house could have been better. You know there need to be some distance between the points. My example was, as you know, a simplification.
It does not need to be better, because our measuring accuracy today is so high that such an effect could easily be found [and would earn its discoverer a Nobel Prize]. But let the outer layer be the satellites in geostationary orbit [38,000 km high]. These do not move one way and the surface the other way as the Earth moves in its orbit. [or just take the Moon, it doesn't do it either]

Then spin the plate slowly, increase and decrease the speed and you will see what I’m telling You will see the water at the inner rim move radially outwards towards to outer rim, but not start the water rotating around the center of the bowl. Instead of a bowl use a long skinny tray reaching from the center of the plate to the outer rim to see what I’m telling. In any event the movement is always away from the axis of the plate regardless of increasing or decreasing speed. The water never begins to move back towards the center. And you are introducing the friction between the bottom of the bowl and the plate to make the water move. Image [as in space] that there were no such friction, then the bowl would just stay put and you can rotate the plate to your heart’s content and the bowl and the water would never move.

By: lgl

lgl — Thu, 11 Dec 2008 18:17:40 +0000

Leif,
Yes you are doing a fine job, I really appreciate it.
Just to clarify the ’sharp bend’ or radius. The radius only matters because it changes through the orbit. That difference makes, or at least reflects, the acceleration. Once the acceleration is determined the radius probably doesn’t matter. Earlier I didn’t realize that if you increase the radius the travelling distance difference between the ‘inner side’ and the ‘outer side’ remains 2*pi*r, (inner side beeing the side of the sun closest to the barycenter and r=solar radius) but, as you know, I have a problem with numbers so not sure my calculations are correct.
Your example with the house could have been better. You know there need to be some distance between the points. My example was, as you know, a simplification.
It’s an easy experiment to do. Just place a bowl of water on a rotating (note, rotating :) plate and place it to one side of the plate so that the rotation center is not at the center of the bowl (sun around the barycenter). Then spin the plate slowly, increase and decrease the speed and you will see what I’m telling. (also put some grains of coffee or something in the water and some color (milk) to get good contrast.)
And of course report your result here :-)
Damn, maybe I have to buy that video camera just to show you.

By: lgl

lgl — Thu, 11 Dec 2008 17:46:49 +0000

Phil,
I like this one better: http://virakkraft.com/PDO-mag-dec.ppt
I agree you can’t really tell whether it’s a 20 yr or 18 yr cycle from this but I took the liberty of using the peaks in the declination curve at 1925 and right before 1980, that’s very close to 18×3 yrs. (and there are of course other cycles making phase shifts)

By: Leif Svalgaard

Leif Svalgaard — Thu, 11 Dec 2008 17:21:18 +0000

Phil. (07:36:51) : lgl (13:06:53) : Here’s the PDO Index [...] Not much indication of an 18 year cycle there. and one would expect a daily effect from the 'mechanism' as the far-side goes in an arc that is 4 times wider than the front-side [towards the Moon]. In any event, there are no such effects and none would be expected because the 'mechanism' does not operate. Nonsense at its finest. But that never deters people, in fact, often is an encouragement ["see, I have an open mind", "I'm able to think outside of the box" - of reason, "I'm on the forefront of the fight against scientific dogma", etc, etc].

By: Phil.

Phil. — Thu, 11 Dec 2008 15:36:51 +0000

lgl (13:06:53) :
Leif,
Yet nobody has ever seen any of the huge effects that must have
Oh yes we have, volcanoes can be hugh. (and there’s a 18-yr cycle in the PDO)

Here’s the PDO Index
http://jisao.washington.edu/pdo/
Not much indication of an 18 year cycle there.

By: Leif Svalgaard

Leif Svalgaard — Thu, 11 Dec 2008 12:04:26 +0000

lgl (00:31:31) :
Imagine there is one inner layer and one outer layer. If you are an observer at the rim of the inner where you can ’see’ the outer layer, when the sun speeds up the outer layer will appear to be moving in one direction, when the sun slows down it will appear to be moving in the other direction.
Since both the inner layer and the outer layer make 292 ‘revolutions’ in 20 years and since both the inner layer and the outer layer go around the barycenter once in 20 years, they both move together and there will be no relative motion as they make the same number of ‘revolutions’ in 20 years.
The Earth turns 366 times in a year. Add 1 revolution going around the Sun [your argument, now]. Imagine there is one inner layer and one outer layer. If you are an observer at the rim of the inner where you can ’see’ the outer layer, when the Earth speeds up the outer layer will appear to be moving in one direction, when the Earth slows down it will appear to be moving in the other direction. Let the floor of my house be in the inner layer and the roof in the outer layer, then as the Earth goes around in its orbit, the floor moves one way and the roof moves the other way. No wonder there is a crack in the wall.

By: lgl

lgl — Thu, 11 Dec 2008 09:16:47 +0000

Sorry I mixed revolution and rotation