Posted on 06/14/2006 8:03:32 AM PDT by Jack Bull
If you read that website and others that discuss Orbital Variance, they have measured changes in the earth's orbital length with atomic clocks. The year is getting longer right now as we also experience warming.
As for why the earth does not follow a perfectly elliptical orbit (or circular) here is a practical reason... when a body is travelling in free space and encounters the gravitational pull of another body, it will (if captured) begin to orbit that body with either an elliptical or circular (both are equivalent with the circle being an ellipse with a single locus) orbit.
Now, over time, the orbiting body will assume a constant orbit if there are no other elements in the equation. However, if there are other bodies with gravitational effects on that body, depending on their orbits and positions at any particular time, they can create shifting effects on that body.
I would speculate that the "alignment of the planets" occurs due to the mixing of their orbital frequencies creating nodes where they combine and cancel their impacts on earth's orbit, thus changing it slightly.
Note, the page I linked shows relationship between the shape of the orbit and global temperatures. Long before human CO2 production began.
If there are other bodies with such a large effect it would be easy to run numerical simulations. The main body, aside from the sun, that has an effect on earth's motion is the moon. As the moon leaves earth, earth's orbit would be affected, but this is not a repeating event. The main motion that has not been satisfactorily explained is the precession of the equinoxes and calling it 'wobble' is probably overlooking an obvious cause.
Wobble does not cover the difference in temperatures. It might effect seismic and therefore geothermal variations, but to dismiss the effect of the planetary gravitational alignments suggests to me that you have not been reading the links I provided.
Right Whale, just one example- the axis of Earth's rotation is indeed precessing and is easily measured by observing Polaris. The circle Polaris makes in the sky is changing.
Back 4000 years ago the pole star was Thuban in Draco, not Polaris.
These orbital wobbles and wiggles are not theory or a model, they are observations.
The theory is that the orbital wiggles can change the Earth's climate- the Milankovich Cycles.
Reading with scepticism.
The wobbles cannot be dismissed as wobbles. They must be explained. Takes more than a wave of the hand.
Ping Big Time
These cycles remain unexplained, and they are inadequate to explain ice ages.
The cycles are, however, observed. They do fall out from the Kepler and Newton equations for orbital motion- they are not mysteries.
The periodicity of the cycles does correlate rather well with glaciation cycles over the last 700 ky, but not perfectly. It seems odd that insolation changes brought about by observed orbital elements would NOT influence climate.
There's lots of stuff written on the topic, much of it online now.
http://en.wikipedia.org/wiki/Milankovitch_cycles
They are mysterious. If there were some theory that explained causes this might be related to science. The original comment was that earth's orbit expands and contracts and that causes an ice age in my attitude. Precession of the nodes is not at all what is being discussed here.
http://en.wikipedia.org/wiki/Precession_of_the_equinoxes
Here is an article explaining the observed precession of the equinoxes. There are other similar articles explaining the other elements of the Milankovich cycles, and I'll leave that to you.
Some of them in 1900 predicted a world wide epidemic of excessive..horse manure. From all of the people using those poor horses...
Ping for future reference. Great article.
How do you know? It isn't 2020 yet. And you are looking awful tasty this morning.
So sorry to hear of your loss. Fortunately for me I survived but eventually starved to death back in 1995 during the "Great Famine"........
This is one of those articles I wish could be sent to every school kid in America. A very important and easily understood article.
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