Change in Earth Precession Axis May Add to Global Warming?

Naomasa298

Forum Staff
Apr 2010
35,031
T'Republic of Yorkshire
#31
The slow rotation is due to tidal locking with Sun. Same effect that has tidally locked Moon to Earth so that we always see the same side. Venus is not quite in full resonance, the Venusian solar year being 1.92 Venusian days.

As for the axis, different mechanisms might be at work. Like MG1962a says, might be a big protoplanetary hit near the beginning. Might be orbital resonances.
The wiki article suggests atmospheric tides may be a factor.

I understand tide locking, but I thought Venus wasn't close enough to the Sun to be tidelocked (given that Mercury isn't).
 
Jan 2009
1,264
#32
I understand tide locking, but I thought Venus wasn't close enough to the Sun to be tidelocked (given that Mercury isn't).
Like said, Venus isn't tidally locked yet, but it is the same effect, gravitational tides, slowing Venus down. Atmospheric tides, as you said. I was a bit inexact in what I said, I should have said tidal interaction rather than tidal locking.

Mercury isn't fully tidally locked either, but it is in a 2/3 resonance (Mercurian year being 1.5 siderial days), resulting in a Mercurian solar day being 2 Mercurian years.

Moon is fully tidally locked. But at the same time, the tides on Earth caused by Moon's gravity are slightly slowing Earth down... and since the angular momentum needs to be conserved, this is making Moon drift a bit farther away in its orbit around Earth. Same effect. Earth is not tidally locked with Moon, but Moon's gravity is still having a slowing effect via tides.
 

specul8

Ad Honorem
Oct 2016
3,351
Australia
#33
That would be correct sir. Uranus is an even more extreme. Whatever hit it, managed to lay the planet over on a 90 degree angle
Just after that (geological time ) the Earth's crust started to form . And around that time , we have the oldest zircon ( yet found ) in one of Australia's cratons .

I mention that as, at the moment , I am traveling through Western Australia (by campervan) through an ancient eroded landscape . - Freaky !


It appears that in the past , 'someone' was playing ' billiards' with our planets .
 
Mar 2019
1,613
Kansas
#34
Just after that (geological time ) the Earth's crust started to form . And around that time , we have the oldest zircon ( yet found ) in one of Australia's cratons .

I mention that as, at the moment , I am traveling through Western Australia (by campervan) through an ancient eroded landscape . - Freaky !


It appears that in the past , 'someone' was playing ' billiards' with our planets .
The last theories I saw on this suggested that as the system formed there were two basic planetary formations, those in reasonable circular orbits and those that developed elliptical orbits. Over a period of time the elliptical planets were ejected from the system but not before some of them made targets of the more stable orbit planets.

So the billiards analogy is surprisingly accurate

And yes 'Jack Hills' possibly oldest evidence of life on Earth as well, though some interesting finds in South Africa might trump the discovery.
 
Likes: specul8

specul8

Ad Honorem
Oct 2016
3,351
Australia
#35
The last theories I saw on this suggested that as the system formed there were two basic planetary formations, those in reasonable circular orbits and those that developed elliptical orbits. Over a period of time the elliptical planets were ejected from the system but not before some of them made targets of the more stable orbit planets.

So the billiards analogy is surprisingly accurate

And yes 'Jack Hills' possibly oldest evidence of life on Earth as well, though some interesting finds in South Africa might trump the discovery.
Yes, the ' Yilgarn Craton' .

I am camped directly west of there on the coast at Shark Bay . Why is Jack Hills mine blue ???? A type of granite ? Its the same color as the zircon .


Google Maps
 
Apr 2017
711
Lemuria
#36
Changes in the axial precession would not cause changes as rapid as what we are seeing today. The changes would be on a geological timescale.
In the past it would maybe cause some droughts and a moderate change of temperature for a period of time, but nowadays the concern is real as it could be a trigger that breaks a system that is heading toward instability.
 

Naomasa298

Forum Staff
Apr 2010
35,031
T'Republic of Yorkshire
#37
In the past it would maybe cause some droughts and a moderate change of temperature for a period of time, but nowadays the concern is real as it could be a trigger that breaks a system that is heading toward instability.
Nonsense. As Whyte pointed out, a complete cycle takes 23000 years. It would not make any difference in a lifetime.
 

sparky

Ad Honorem
Jan 2017
4,786
Sydney
#38
since the young Earth was hit by a smaller planet , we have a moon made of debris and the Earth rotating pretty fast with a wobble
by the time of life explosion the day was 17 of today hours long ,the Earth was warm
as the ages passed the global temperature has decreased , poles started to appear
an unprecedented serie of Ice ages set the Earth climate into a saw tooth cycle demonstrating the instability of the thermal system
the Milankovich cycles provide a good hypothesis but do not explain why it is happening only since 2 millions years ago but not before

the impact of humans can confidently be considered as nefarious but it would seems that the slowing Earth might get to a new state of thermal equilibrium