Earth's Orbit Inclination Precession, Last 10 Myr

[jayaminilosini]

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[Tweekerhead]

So whata' think the Ice Age comes almost one outta' every four 26,000 year precession cycle ?

Maybe the ancients were trying to tell us something when they named the constellation Aquarius, the water bringer. Every time the Earth enters the age of Aquarius the Earth warms and the seas rise. I think the ancient Egyptians call Aquarius "Hapy" with the same water theme...I believe.

Just a thought, interesting vid'.

[freethisone]

@Tweekerhead i have the answer to this ice age question, but you wont like the truth..

[Tweekerhead]

@freethisone Whata' you mean I won't like the truth? I'm only interested in the truth are you?

Milankovitch cycles ..that's the truth.

[Tweekerhead]

@freethisone Oh you're one of those Nibiru-Annuanki folks....LOL

Good luck with that, 2012 will be here real soon so we can all laugh people like you ..sorry.

BTW according to Marshal"Mastercard" Masters it should be a couple of AU's out, but still can't see it I'm afraid.

;-))

[freethisone]

@Tweekerhead marshal masters lol, he was the biggest anti nibiru guy out there, until his eyes were opened. now he speaks as if it is real.

you wanna know when the worst will hit? that is the next 4 months. so don't think it means the end of the world.

that's why you will be part of the cheerleader section, that said 2012 was nothing. but of course you can see the truth?

It is and will be epic in the short 3 years to follow. a great quake will be an eye opener to the world. Battle LA?

[Tweekerhead]

@freethisone Masters is a hustler trying to make a some buck$, that's all he knows nothing about science or astronomy.

Nibiru is a hoax, plain & simple. I's just not there, it should be as close Jupiter is now but it's not, because it doesn't exist.

Save your money.

[rowania]

conjecture

[AcePilot101]

Precession cycle is roughly 26,000 years. Both the Lake Vostok and Epica ice core studies indicate carbon dioxide levels rise for 21,000 years before the earth cools.

The last ice age was about 18,000 years ago so we are still in a warming phase.

[freethisone]

@AcePilot101 the ice age begun after the first great quake of 2010.

[AcePilot101]

Precession drives climate change, just as the tilt of the axis gives us winter and summer.

[TheLoggah]

another question: What is your opinion about JPL's scientists claiming that Global Warming may end up shifting the Earths tilt by as much as 1.5 cent./year? And that the recent earthquake in Chile may have shifted the earth's tilt as well as the tsunami in 2004?

[TheLoggah]

another question: what role does the Earth's magnetic field play in its precession? Does it have any different affect on it when it changes polarity as it is apperently in the middle of doing now?

[lpetrich]

@TheLoggah It's too weak to have much of an influence on the Earth's precession. The Earth's rotational kinetic energy is 2.19*10^(29) joules, while the Earth's magnetic-field energy is around 10^(18) joules (rough estimate). The interaction energy for the Earth and the interplanetary magnetic field is even less, about 10^(14) joules (another rough estimate).

[TheLoggah]

a question: does the changing "flexibility" of the Earth affect this precession? Is it what causes it? If we currently have huge amounts of water frozen at the poles ....and that water melts...wouldn't it be pulled more towards the moon? I'm wondering if this added bulge would be like a spinning skater extending one arm out and causing the skater to wobble and also to slow down?

[lpetrich]

@TheLoggah That flexibility has nothing to do with it. It's the pull of the Sun and the Moon on the Earth's equatorial bulge that cause its spin precession. Continental glaciers coming and going will affect the Earth's shape and spin rate a tiny bit,

The current "post-glacial rebound" from rocks springing back from glaciers being gone does make a tiny effect on the Earth's spin rate. A decrease of about 0.7 milliseconds per century -- teeny tiny.

[solvssod]

what the hell was that

[344thBrother]

Also, the moon is near perigee we had a Wolf moon in January I think it was. It's visibly bigger lately. How much affect does this have on precession and thus the tides? Those massive waves at the Mavericks surf contest in February were amazing! Related?

[lpetrich]

The Moon's orbit's eccentricity is about 0.055. That makes the Moon's tides vary all the way to 15% of their average value.

As to precession, the effect is much smaller, because the rate variation due to eccentricity approximately cancels out over the Moon's orbit. What remains gives an additional precession of 0.15%.

As to that surf, it seems like some function of the weather somewhere; I wouldn't have any idea.

[344thBrother]

Thank you for your answers above. Very clear.

Woohoo! More warming!

Next questions. How much distance is covered in a large "precessional" wobble... (give me a better term for this too please).

And. What is the time frame that these videos cover?

Nice site, very interesting and informative.

[lpetrich]

No linear distance. To get angular "distance", multiply those numbers by 115 (360/pi).

So the wobbles are at most about 2 degrees from their central point, the direction of the Solar System's angular momentum.

[lpetrich]

The time frame is the last 10 million years - the middle-late Miocene to the present.

[344thBrother]

2 questions please:

The tracing represents the exact axis of the earth wobbling off center, right? What is the time frame?

Where are we in the Milancovich Cycle at the moment. Should we expect cooling or heating? I'm guessing cooling.

peace freedom truth justice

d

[lpetrich]

That's the direction of a line perpendicular to the Earth's orbit plane. In effect, the Earth's orbit north pole.

We are now in the middle of an interglacial, a warm period between Ice Ages. It's not very certain how long it will last. One estimate says about 50,000 years.

Search for "Milankovitch cycles" in Wikipedia for a nice introduction; I can't post links here.

[yummyseed]

Looks more like the halley's comet orbit ,rather then our earth

[lpetrich]

It's not the Earth in its orbit, it's how its north pole precesses.

[Mike2008and2008]

this is awesome!

[poniesareawesome]

Does anyone know how the Portuguese used the Arab instruments of astronomic calculation to make the first tables of declination? I have been searching for the answer for about two or three hours and have found nothing at all. Any websites would be awesome, too. Thanks (:

And this video is pretty cool.

[Quast]

What was the closest spot of earth to the sun the last 10mil years? I would look it up myself but I don't even know what atn1/2..something...is meaning

[lpetrich]

Closest approach? The planets' major axes stay approximately constant over time, so the Earth gets closer to the Sun at closest approach when its orbit eccentricity goes up. It's now 0.0167, but its average is about 0.03 and its max is 0.06. So it goes from being a few percent closer to a few percent farther: (1 - ecc) to (1 + ecc).

[weisserabfall]

qeustion :wouldnt the gyroscopic effect be more of a pluassable cause for climate change????

[lpetrich]

That's indeed what happens. The Earth's spin precesses relative to its orbit, and its orbit-plane precession causes the Earth's axial tilt to change. This produces changes in the pattern of incoming sunlight called "Milankovitch cycles". These are closely correlated with the ice ages of the last 2 million years. When northern summers are not warm enough, ice accumulates, and when northern summers get warmer, that ice melts.

[weisserabfall]

thank you sir

[hadtohappen]

Wait a minute. If all the bodies in the solar system are mutually interacting this way. I am skeptical that we can simply "run the equation backwards". Small changes in initial conditions, and incomming and outgoing bodies, --even if small-- over a long time-- would change things quite a lot. No?

[lpetrich]

Yes, that is a potentially serious problem, but celestial mechanicians have addressed it.

They are helped out by the Sun's much greater mass than the planets, which makes the planets' orbits close to two-body ones (Sun/Jupiter: 1000, Sun/Earth: 333,000), and also by the extreme precision that one can get for the planets' positions -- better than one part in a million.

[lpetrich]

However, calculations like the ones I've used have revealed that the planets are in a state of weak dynamical chaos. Their overall behavior has remained the same over the history of the Solar System, with the orbits staying about the same in size and having roughly the same precession cycles. However, extrapolating precise positions is difficult past about 100 million years due to the chaos.

[lpetrich]

The effect of changing the planets' orbit parameters at some time will be exponentially magnified, getting multiplied by e (~2.718) each 5 to 10 million years, the 'Liapunov time".

There is dynamical chaos elsewhere in the Solar System, like in the rotation of Saturn's moon Hyperion, which is chaotic tumbling at about the period of Hyperion's orbit around Saturn.

[TheInternetMurderer]

When I read about Milankovitch cycles it seemed as though the cycle was constant. Does this theory postulate that the Milankovitch cycles are caused by this 'tug of war' with the gravitational pulls of other planets? If so this would make a lot of sense and explain the Milankovitch cycles. But I am curious as to why there does not seem to be an exact repetition of any one 'pattern'. Would the entire sequence repeat itself after 10Myr? Or is it 'thrown off' by its own changes (ie chaotic)?

[lpetrich]

The individual periods are not simple multiples or fractions of each other, like 2/1 or 3/2, which means that their combination won't repeat. So that's how a non-repeating curve arises from repeating individual cycles.

[bignewgame]

Would the precession be explained if this was a binary star system?

[lpetrich]

If the Sun was a star in a binary star system, the Sun's companion would make the Sun's planets' orbits precess. If the Sun was a binary much like Alpha Centauri, with a Sunlike companion at 20 AU, then the Earth's orbit precessions would have periods around 10,000 years.

[gerkins1]

Now I know where people get their ideas for those spiral games!

[wilburhubbard]

the moons proximity to earth affects the speed of the earths rotation; daily tidal deposits from austrailia from 365 million years ago show that a day was only 22 hours long. the moon is moving away from us at a speed of 4cm/yr so all those people that wish there were more hours in an day, you just have to wait a few hundered million years...

[Quast]

@wilburhubbard

Well, I wish for a 26hrs day!...darn so I still have to wait ~360mil yrs?

And I would like to try out the 26/9 week (9-days week)!

[lpetrich]

It's easy to show that that's too tiny to have much of an effect; for starters, the amount of mass shifting involved is MUCH less than the Earth's mass. So it's not worth losing sleep over.

[seenshoo]

Is there any chance that Earth's orbit is affected by massive landscape changes around the world? Like digging and constructing and ice melting etc?

[lpetrich]

The Earth's spin precesses because the Sun and the Moon pull on the Earth's equatorial bulge, trying to make it un-tilted. Likewise, the Earth's orbit precesses because the other planets try to pull the Earth toward the average of their orbit planes. But since there are several planets pulling on the Earth with similar-sized effects, the Earth's orbit precession is much more complicated, as you can see.

[buahpetai]

uhhh.... what's happening, bro?

[shih1]

I'm not sure whether i get this entirely...