Any Changes in Earth's Orbit or Rotation?

baywax

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/new...ews.cfm?id=771

Here's another,

Sudden climate transitions during the Quaternary

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

If this is a repetition of an earlier thread please link from here to it, thank you.

D H

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.

baywax

I would be interested to see a link or paper that supports your statement.

D H

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?

baywax

I don't know and I'm not going to assume anything. That's why I'm asking.

D H

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.)

Andre

This thread may contain some useful information about the milankovitch cycles, the correlation witrh climate, but also the problems with that.

baywax

Part of the research I'm doing is asking questions.

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.

billiards

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.

baywax

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/s.../2003_4_c.html

It talks about how

...and seems to say exactly what you're saying in your post.

Very interesting Check it out.

One more quote

russ_watters

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.

baywax

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 with a rotation as eccentric as a baseball partly filled with mercury.

russ_watters

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.

William Astley

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/I...s/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/%7Eshaviv...torfDebate.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.)

baywax

OK Russ. Thanks!

baywax

That's very interesting, thank you.

baywax

This time I mean it. Really fascinating stuff William.

From Williams link, http://www.phys.huji.ac.il/~shaviv/I...s/GSAToday.pdf

Myopic views about climate change tend to sometimes miss the big picture and the "big" effects.