Any Changes in Earth's Orbit or Rotation?

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  • #1
baywax
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Main Question or Discussion Point

Has the rotation or the orbit of the earth gone through any significant or other changes in the past 100 years?

This astrobiology article talks about some of the possible effects of orbital changes in the distant past.

http://astrobiology.arc.nasa.gov/news/expandnews.cfm?id=771 [Broken]

Here's another,

Sudden climate transitions during the Quaternary

http://www.esd.ornl.gov/projects/qen/transit.html [Broken]

If this is a repetition of an earlier thread please link from here to it, thank you.
 
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  • #2
D H
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The Earth's orbit and rotation do change, but gradually and slowly. Nothing significant has happened in the last one hundred years.

One the other hand, the Earth's climate is a non-linear system. It can (per models) and has (per inference from observations) exhibit marked non-linear responses to smooth changes in the eccentricity, obliquity, and precession. That said, there have been no apparent climatic triggers from these factors over the last hundred years.
 
  • #3
baywax
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The Earth's orbit and rotation do change, but gradually and slowly. Nothing significant has happened in the last one hundred years.

One the other hand, the Earth's climate is a non-linear system. It can (per models) and has (per inference from observations) exhibit marked non-linear responses to smooth changes in the eccentricity, obliquity, and precession. That said, there have been no apparent climatic triggers from these factors over the last hundred years.
I would be interested to see a link or paper that supports your statement.
 
  • #4
D H
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Which statement? That Earth's climate is non-linear is well-known. You can find many papers on this.

Regarding the lack of cause: First, such a statement it is not worthy of a paper. Second, don't you think the anti-global warming crowd would be all over this if there was any hint that the warming could be attributed to the Earth's orbital eccentricity or the obliquity of the ecliptic?
 
  • #5
baywax
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don't you think the anti-global warming crowd would be all over this if there was any hint that the warming could be attributed to the Earth's orbital eccentricity or the obliquity of the ecliptic?
I don't know and I'm not going to assume anything. That's why I'm asking.
 
  • #6
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Then do some research on this yourself. No journal is going to publish a paper about the non-existance of an inconsequential result. You might find that some global warming studies have done due diligence and ruled out such effects. You will find papers that suggest we should be going back to an ice age. (Actually, we are still in an ice age. We just happen to be between in an interglacial whose time should be just about up.)
 
  • #7
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This thread may contain some useful information about the milankovitch cycles, the correlation witrh climate, but also the problems with that.
 
  • #8
baywax
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Then do some research on this yourself. No journal is going to publish a paper about the non-existance of an inconsequential result. You might find that some global warming studies have done due diligence and ruled out such effects. You will find papers that suggest we should be going back to an ice age. (Actually, we are still in an ice age. We just happen to be between in an interglacial whose time should be just about up.)
Part of the research I'm doing is asking questions.

Andre said:
This thread may contain some useful information about the milankovitch cycles, the correlation witrh climate, but also the problems with that.
There are so many discrepancies going on with the research into this that I have to weigh each paper and article against the next. Even when you find that a higher percent of them say the same thing there remains a lot of doubt ie: the repeatedly incorrect (as you pointed out) suggestion that the perihelion becomes as much as 30% more distant than the apohelion of the earth's orbit.
 
  • #9
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AS far as I am aware the length of an earth day is gradually increasing as the rotation slows down (although my lecture notes seem to say days are getting shorter for some strange reason!). The mechanisms responsible for the gradual slow down are tidal coupling, where the moon pulls the ocean back and viscous drag which is related to whole earth deformations. However the slow down is not as simple as it might first appear, there are short period fluctuations in the length of the day attributed to momentum transfer with the atmosphere, and there are longer period fluctuations attributed to momentum transfer within the core.
 
  • #10
baywax
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AS far as I am aware the length of an earth day is gradually increasing as the rotation slows down (although my lecture notes seem to say days are getting shorter for some strange reason!). The mechanisms responsible for the gradual slow down are tidal coupling, where the moon pulls the ocean back and viscous drag which is related to whole earth deformations. However the slow down is not as simple as it might first appear, there are short period fluctuations in the length of the day attributed to momentum transfer with the atmosphere, and there are longer period fluctuations attributed to momentum transfer within the core.
I've found a few articles on tidal coupling. This one shows how dramatic changes can take place because of it, but this has to do with a Neutron Star's gravitational pull with a companion

Resonant tidal excitations of rotating neutron stars in coalescing binaries

http://adsabs.harvard.edu/abs/1998astro.ph.12116H

This link below is the "Lava-Lamp Model for Gravitational Core-Mantle Coupling" and is directly from the govt. itself.

http://denali.gsfc.nasa.gov/sci_hi/sci_hi_04_03/2003_4_c.html

It talks about how

...it has been known for a long time that the Earth’s rate of rotation is changing. Post- glacial rebound causes a small acceleration, but this is more than offset by lunar tidal friction which is slowing down the Earth’s rotation and making the day longer. There are historical records that suggest there is also some episodic or perhaps periodic disturbance of the secular or long-term slowdown
...and seems to say exactly what you're saying in your post.

Very interesting:bugeye: Check it out.

One more quote

There may be a 1000 year periodic change in the Earth’s Length of Day (LOD)

In a paper accepted for publication in the Journal of Geophysical Research – Solid Earth, David Rubincam looked at whether coupling between the liquid outer core and the mantle might be responsible for the suspected 1000 year timescale. He studied the effects that might result from the gravitational attraction between density anomalies or “blobs” in the outer core and mantle. The core anomalies, which would randomly come and go like the blobs in a lava lamp (see figure below), would cause time-variability in the gravitational attraction between the outer core and mantle, in turn producing torques which could affect and change the rotation rate between the two parts of the Earth.
:surprised
 
  • #11
russ_watters
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If you want evidence, we have good records of astronomical observations dating back 500 years. Predicting things like eclipses requires a pretty precise understanding of such things. They would have picked-up any changes. Also, the earth's rotation is very closely monitored for the purpose of time coordination.
 
  • #12
baywax
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Also, the earth's rotation is very closely monitored for the purpose of time coordination.
Thank you Russ. This is one reason I'm asking the question about orbit and rotation. Has the close monitoring of earth's rotation resulted in a daylight savings time earlier start date?

If the early start was soley initiated to save energy, why isn't it a whole month earlier? Why not 2 months? I'm just curious about the specificity of 3 weeks. I wondered if governments don't want to shake things up with the idea that we are gaining daylight because of the above mentioned 1000 year cycle or because the earth is actually one big Lava Lamp :smile: with a rotation as eccentric as a baseball partly filled with mercury.
 
  • #13
russ_watters
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Has the close monitoring of earth's rotation resulted in a daylight savings time earlier start date?
There is a thread on the DST shift in GD. It is purely a political choice. It was done so politicians could pretend to be environmentalists.
If the early start was soley initiated to save energy, why isn't it a whole month earlier? Why not 2 months?
Because then it would be dark in the morning and there'd be no benefit.
I'm just curious about the specificity of 3 weeks.
It is totally arbitrary. It even varies by state.
I wondered if governments don't want to shake things up with the idea that we are gaining daylight because of the above mentioned 1000 year cycle or because the earth is actually one big Lava Lamp with a rotation as eccentric as a baseball partly filled with mercury.
Now you're making up your own new conspiracy theory. Please stop being so rediculous - we don't allow it here.
 
  • #14
Changes in Galactic Cosmic Rays, Initiate Ice Ages?

In reply to Baywax's question, what started this ice age?

It should be noted that Antarctic has been polar centric for almost 100 million years and there has no Antarctic ice sheet for 75 million years. (Flora and fauna lived on the Antarctic continent while it was polar centric.) The ice sheets began to form on Antarctic roughly 25 MM years ago. The cause of the Antarctic ice sheet formation was not due to orbital changes and has not due to a drop in CO2 levels. (CO2 was high when the Antarctic ice sheet began to form. Orbital changes do not change the total amount of insolation only whether summer is relatively warmer and winter is relatively colder or visa versa. See thread what cause Ice Ages for details.)

Attached is a link to Shaviv and Vezier’s paper that shows there is correlation between the start and end of the glacial epoch with increases and decreases of Galactic Cosmic Rays (GCR). Shaviv examined meteoroids to find how intensity of GCR has varied over time. The increase and decrease of GCR correlates with the passage of the solar system through the spiral arms of the galaxy. GCR intensity is higher in the spiral arms as there is higher formation of stars in the arms.

http://www.phys.huji.ac.il/~shaviv/Ice-ages/GSAToday.pdf

Also attached is Shaviv and Vezier’s response to criticism. The issue is sensitive as if Shaviv and Vezier’s assertions are correct the current general climate models have over estimated the sensitivity of planetary temperature to CO2 level.

http://www.phys.huji.ac.il/~shaviv/ClimateDebate/RahmstorfDebate.pdf

See the thread in this forum "Clouds and Reflectivity" for how it is hypothesized that GCR changes affect low level cloud intensity. (Increase in clouds cause the planet to cool and visa versa.)
 
  • #15
baywax
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There is a thread on the DST shift in GD. It is purely a political choice. It was done so politicians could pretend to be environmentalists. Because then it would be dark in the morning and there'd be no benefit. It is totally arbitrary. It even varies by state. Now you're making up your own new conspiracy theory. Please stop being so rediculous - we don't allow it here.
OK Russ. Thanks!
 
  • #16
baywax
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In reply to Baywax's question, what started this ice age?

It should be noted that Antarctic has been polar centric for almost 100 million years and there has no Antarctic ice sheet for 75 million years. (Flora and fauna lived on the Antarctic continent while it was polar centric.) The ice sheets began to form on Antarctic roughly 25 MM years ago. The cause of the Antarctic ice sheet formation was not due to orbital changes and has not due to a drop in CO2 levels. (CO2 was high when the Antarctic ice sheet began to form. Orbital changes do not change the total amount of insolation only whether summer is relatively warmer and winter is relatively colder or visa versa. See thread what cause Ice Ages for details.)

Attached is a link to Shaviv and Vezier’s paper that shows there is correlation between the start and end of the glacial epoch with increases and decreases of Galactic Cosmic Rays (GCR). Shaviv examined meteoroids to find how intensity of GCR has varied over time. The increase and decrease of GCR correlates with the passage of the solar system through the spiral arms of the galaxy. GCR intensity is higher in the spiral arms as there is higher formation of stars in the arms.

http://www.phys.huji.ac.il/~shaviv/Ice-ages/GSAToday.pdf

Also attached is Shaviv and Vezier’s response to criticism. The issue is sensitive as if Shaviv and Vezier’s assertions are correct the current general climate models have over estimated the sensitivity of planetary temperature to CO2 level.

http://www.phys.huji.ac.il/~shaviv/ClimateDebate/RahmstorfDebate.pdf

See the thread in this forum "Clouds and Reflectivity" for how it is hypothesized that GCR changes affect low level cloud intensity. (Increase in clouds cause the planet to cool and visa versa.)
That's very interesting, thank you.
 
  • #17
baywax
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This time I mean it. Really fascinating stuff William.

ABSTRACT
Atmospheric levels of CO2 are commonly
assumed to be a main driver of
global climate. Independent empirical evidence
suggests that the galactic cosmic
ray flux (CRF) is linked to climate variability.
Both drivers are presently discussed
in the context of daily to millennial variations,
although they should also operate
over geological time scales. Here we analyze
the reconstructed seawater paleotemperature
record for the Phanerozoic (past
545 m.y.), and compare it with the variable
CRF reaching Earth and with the
reconstructed partial pressure of atmospheric
CO2 (pCO2). We find that at least
66% of the variance in the paleotemperature
trend could be attributed to CRF variations
likely due to solar system passages
through the spiral arms of the galaxy.
Assuming that the entire residual variance
in temperature is due solely to the CO2
greenhouse effect, we propose a tentative
upper limit to the long-term “equilibrium”
warming effect of CO2, one which is potentially
lower than that based on general
circulation models.
From Williams link, http://www.phys.huji.ac.il/~shaviv/I...s/GSAToday.pdf [Broken]

Myopic views about climate change tend to sometimes miss the big picture and the "big" effects.
 
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  • #18
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It's interesting for me to add that the changing in the speed of rotation might provide a possible mechanism for Andre's pulsating equator.

But do the patterns fit? Given that the rotation speed changes rhythmically, with a known period (that I don't happen to have right now), does the climate evidence fit? What would happen if we corrected for Milankovic effects?
 
  • #19
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I'm discussing some of the the same things now with somebody who calls one sort of the named Pleistocene events "my" events. There were six of those events, actually seven if you start counting at zero.

This is part of what I replied to him:

First of all a possible cause for a "wobbling" Earth. I already refered to the Earth as a complex set of different gyroscopes subject to orbital and spinning perturations, causing precession and obliquity cycles. Newton already explained the cause of the precession cycle to be gravity difference on the far side and close side of the equatorial bulge and the moon and the sun, causing a torque force, attempting to erect the earth spinning axis perpendicular to the plane of the sun / moon orbits. However the spinning causes a precession reaction. This means that the spin axis of the crust-mantle part of the Earth moves around in a cone. But how about the spin axis of the core?

We wonder about the small solid inner core, which shape depends on the pressures and temperature, much more than the centrifugal force. Therefore the solid inner core may not have a equatorial bulge comparable to Earth and even if so, it will still react differently to the Solar and Moon gravitation because the parameters are different. Hence, the solid inner core has a different precession logic independent of the mantle.

The fluid outer core is supposed to stabilize the spin axis of the inner core and acts as a torque converter just like in cars with automatic transmissions. We assume that it's stabilizing capacity is limited and when the size of the solid inner core increases due to cooling, it takes over a tremendous amount of annular momentum, while decreasing the stability capacity of the outer core. As a result, at a certain moment, like, for instance, perhaps 17,5 Ka ago, the spin axis of the solid inner core may break lock with the spin axis of the mantle. This will cause tremendous unstable flows in the outer core, resulting in pressure differences on the core mantle boundary, which ultimately will have dynamic effects on the shape of the Earth.

Next the turbulence will generate additional friction heat, with will cause melting and reduction of the size of the solid inner core again, which may eventually stabilize the complete core again, especially when the inner core has completed it's own independent precession cycle. Then the core would cool again, causing the inner core to grow until again it's spin axis breaks lock and the next cycle starts, say maybe 100 ka years later. Perhaps this whole process started say about one Ma ago, when the solid inner core exceeded stabilitity limits for the first time. Also, the strongly reacting oceans may have caused the Mid Pleistocene Stilostomella extinction event at that time.
 
  • #20
baywax
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I'm discussing some of the the same things now with somebody who calls one sort of the named Pleistocene events "my" events. There were six of those events, actually seven if you start counting at zero.

This is part of what I replied to him:
Do you think the bolide incident of 65 mya could have introduced some change/effect on the gyroscopic actions of the cores and mantle? This mass extinction and its cause could also represent some kind of strong influence on the earth's weather today.
 
  • #21
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Do you think the bolide incident of 65 mya could have introduced some change/effect on the gyroscopic actions of the cores and mantle? This mass extinction and its cause could also represent some kind of strong influence on the earth's weather today.
Richard Muller has an interesting thesis about bolide impact and the Earth magnetic field.

http://muller.lbl.gov/

No down links, I'm afraid, so hit "core-mantle boundary" at the left overview and then hit "Avalanches at the Core-Mantle Boundary":

Anyway, he could be right or not. a bolide may do damage (restructuring) to the interior and cause the flood basalt volcanisms and super chrons. The conservation of momentum may cause a infinitesimal small change in Earths spinning rate and orbit parameters. Our mechanism is not related to that.

Incidentely, note that Richard Muller is about the only scientist who thinks deductively, from big to small. Mechanisms first, then fill in the details. If they fit, fine, if not, next big idea.
 
  • #22
baywax
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Richard Muller has an interesting thesis about bolide impact and the Earth magnetic field.

http://muller.lbl.gov/

No down links, I'm afraid, so hit "core-mantle boundary" at the left overview and then hit "Avalanches at the Core-Mantle Boundary":

Anyway, he could be right or not. a bolide may do damage (restructuring) to the interior and cause the flood basalt volcanisms and super chrons. The conservation of momentum may cause a infinitesimal small change in Earths spinning rate and orbit parameters. Our mechanism is not related to that.

Incidentely, note that Richard Muller is about the only scientist who thinks deductively, from big to small. Mechanisms first, then fill in the details. If they fit, fine, if not, next big idea.
This is the guy we need to talk to about a lot of this stuff. He does very diverse yet focused work . Thanks Andre. Nemisis might be a red dwarf! And I thought it was an astro-conspiracy theory.:uhh:
 

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