Magnetic heating and slowing of the earth's rotation (split from axial tilt and length of day)

[John Cuthber]

Why I don't accept heat driven convection as the most probable cause is that convection would have equal amounts of material going up as down (whatever opposite direction you decide. So if the up current tended to produce a south pole wouldn't the down part of the same convection loop negate that?

 

 

No.

That's like looking at a simple "coil of wire round a nail" electromagnet and saying "wouldn't the current going from the back of the coil to the front negate the field produced by the current flowing from the front of the coil to the back?"

[Robittybob1]

No, for the same reason they don't cancel in a solenoid. Current loops create magnetic fields. Further, talking about creating a single pole is nonsensical — an "up current" would create field that went around in a circle, according to the right-hand rule. Have you ever actually studied this?

 

 

Can I prove it? Nope. I'm not a geophysicist. Are there papers by scientists studying this, laying out why this is the best fit to the evidence? Absolutely.

 

 

 

How would they measure the rotation of anything other than the surface?

 

 

If you are going to advance it here you need to move in that direction.

 

 

Nope. Not my burden of proof, it's yours. YOU need to make a physics argument to support your assertion.

I still can't understand how you say I haven't presented physics to support my assertion.

 

Do you think the loops of current are in the Earth's OC? And these are loops of thermal flows of molten metal caused by convection? Have you really checked these out? If you can say you agree with the alternative model, I'll try and understand it better.

No.

That's like looking at a simple "coil of wire round a nail" electromagnet and saying "wouldn't the current going from the back of the coil to the front negate the field produced by the current flowing from the front of the coil to the back?"

So you think you can get all the flows to have the same direction of looping so it becomes like a coil?

[swansont]

I still can't understand how you say I haven't presented physics to support my assertion.

 

That's part of the problem.

 

Point me toward any math you've presented to support this. I see formulas you wrote down or quoted, but you didn't actually apply any of them. You quoted someone else who did (and agreed that their work, which excludes your conjecture, is correct).

 

You have no mechanism by which the earth's magnetic field affects the moon. You have not shown that any other slowing is going on (there are some effect, which are not magnetic in nature). You have a hand-wave, and link some pop-sci level concepts together. But you aren't doing any actual physics.

 

Do you think the loops of current are in the Earth's OC? And these are loops of thermal flows of molten metal caused by convection? Have you really checked these out? If you can say you agree with the alternative model, I'll try and understand it better.

The geodynamo in not the "alternative" model. These are not two ideas on equal footing.

 

So you think you can get all the flows to have the same direction of looping so it becomes like a coil?

 

Yes. The earth spins.

http://en.wikipedia.org/wiki/Dynamo_theory

[Robittybob1]

 

That's part of the problem.

 

Point me toward any math you've presented to support this. I see formulas you wrote down or quoted, but you didn't actually apply any of them. You quoted someone else who did (and agreed that their work, which excludes your conjecture, is correct).

 

You have no mechanism by which the earth's magnetic field affects the moon. You have not shown that any other slowing is going on (there are some effect, which are not magnetic in nature). You have a hand-wave, and link some pop-sci level concepts together. But you aren't doing any actual physics.

 

The geodynamo in not the "alternative" model. These are not two ideas on equal footing.

 

 

Yes. The earth spins.

http://en.wikipedia.org/wiki/Dynamo_theory

Figure 6 in the paper by Martin Wolf shows an exaggerated displaced IC. Even if it was drawn to scale and operated on the daily rotation there becomes so much mixing in the OC that I believe experimentation would show that thermally induced convection flows causing the dynamo effect are unlikely.

I am convinced at the level of basic understanding of flowing liquids you can't really accept both at the same time.

[Bignose]

show that thermally induced convection flows causing the dynamo effect are unlikely.

So, why don't you quantify this some? This is where actual scientists would do a "back of the envelope" calculation. That is, they aren't looking for an exact answer, but using best available estimates and seeing if the orders of magnitude play out.

 

That is, we know about convection flows (see fluid mechanics). We know about thermally induced flows (see both fluid mechanics and heat transfer). And we know about dynamos (see electromagnetic dynamics). Use some numbers and quantify it.

 

This is essentially what swansont is also asking.

[Robittybob1]

Figure 6 in the paper by Martin Wolf shows an exaggerated displaced IC. Even if it was drawn to scale and operated on the daily rotation there becomes so much mixing in the OC that I believe experimentation would show that thermally induced convection flows causing the dynamo effect are unlikely.

I am convinced at the level of basic understanding of flowing liquids you can't really accept both at the same time.

Upon driving to work thinking about the effects I would be willing to modify this by saying "even if it was drawn to scale and operated on the daily rotation there becomes so much mixing in the equatorial regions of the OC that I believe experimentation would show that thermally induced convection flows causing the dynamo effect are unlikely there and only likely in the polar portions (NW -N- NE and the SW -S- SE sectors).

I am convinced at the level of basic understanding of flowing liquids you can't really accept both at the same time in the middle region.

So, why don't you quantify this some? This is where actual scientists would do a "back of the envelope" calculation. That is, they aren't looking for an exact answer, but using best available estimates and seeing if the orders of magnitude play out.

 

That is, we know about convection flows (see fluid mechanics). We know about thermally induced flows (see both fluid mechanics and heat transfer). And we know about dynamos (see electromagnetic dynamics). Use some numbers and quantify it.

 

This is essentially what swansont is also asking.

I did do a kitchen bench experiment last year and the flow lines as per diagram 6 were certainly visible in the narrow portion but where the flows widden again there is a lot of turbulence where the fast flow enters the slow liquid. OK this, as Fig 6 does too, represents what happens at the equatorial region only.

That turbulent mixing would be far more vigorous than any thermally induced convection flows.

Edited March 8, 2015 by Robittybob1

[Bignose]

I did do a kitchen bench experiment last year ...

Ok, so you have a qualitative data point. That's a step. But what's being asked is for a quantitative data point.

[Robittybob1]

Ok, so you have a qualitative data point. That's a step. But what's being asked is for a quantitative data point.

We could estimate how much faster on average the fluid on the narrower side has to go compared to the wide side when the full 60 km displacement of the IC is in effect.

The full volume of the OC has to go through the narrowed part every day (every 24 hour period)

Volume of the OC 4/3 * Pi() * r(OC) ^ 3 - (volume of the IC = 4/3 * Pi() * r(IC) ^ 3). The difference in throat size = difference in cross sectional area +/- area of section of the IC full diameter times 60 km.

 

radius of the earth's inner core 1220 kilometers

radius of the earth's outer core is about 3480 kilometers with a thickness being that minus the 1220 km = 2260 kilometers.

Throat size on the narrowed side 3.78995E+13 m^2

Throat size on the widened side 3.81923E+13 m^2

Ratio of port sizes = 1.0077

So the flow rates will be in the inverse proportions to get the same amount of liquid going through the narrow as the wide.

The increased flow rate at an average shorter distance to the metallic Inner Core is equivalent to a higher current through the narrow side compared to the wide side.

[complete, errors corrected and pasting error corrected]

Edited March 9, 2015 by Robittybob1

[Robittybob1]

This sentence intrigues me: http://astrogeo.oxfordjournals.org/content/49/5/5.5.2.full

 

The solid inner core was deduced from phase relationships and the temperatures and pressures of the core, which show the core slowly crystallizing from the centre outwards.

Would that imply the displacement of the Earth's IC is going to get larger as time marches on? No I think it implies the hydrodynamic bearing effect will tend to keep it more centralized.

As it gets bigger the density is not always going to stay the same, in fact its average density will be declining. Will that mean buoyancy and gravity will equalise too?

What will these changes make to the equations used in that analysis by Martin Wolf? Does it still make sense?

Has anyone understood that paper? http://arxiv.org/ftp/arxiv/papers/1302/1302.3960.pdf

[Robittybob1]

In my effort to understand the geomagnetic production from the thermal loops in the OC I became aware of a major difference between the idea I developed over the last year and the Geo-dynamo.

With the idea I am working on the electrical current is the flowing OC and that passes near the crystalline metallic IC so I envisioned the whole of the IC being induced as a magnetic core, whereas the Geo-dynamo has the electromagnet being developed within the OC only.

[swansont]

We could estimate how much faster on average the fluid on the narrower side has to go compared to the wide side when the full 60 km displacement of the IC is in effect.

The full volume of the OC has to go through the narrowed part every day (every 24 hour period)

Volume of the OC 4/3 * Pi() * r(OC) ^ 3 - (volume of the IC = 4/3 * Pi() * r(IC) ^ 3). The difference in throat size = difference in cross sectional area +/- area of section of the IC full diameter times 60 km.

 

radius of the earth's inner core 1220 kilometers

radius of the earth's outer core is about 3480 kilometers with a thickness being that minus the 1220 km = 2260 kilometers.

Throat size on the narrowed side 3.78995E+13 m^2

Throat size on the widened side 3.81923E+13 m^2

Ratio of port sizes = 1.0077

So the flow rates will be in the inverse proportions to get the same amount of liquid going through the narrow as the wide.

The increased flow rate at an average shorter distance to the metallic Inner Core is equivalent to a higher current through the narrow side compared to the wide side.

[complete, errors corrected and pasting error corrected]

 

So now go to the next step and show how a ±0.4% change in the width affects convection, using some fluid flow equations, in support of your hypothesis. Then go from there.

 

If you aren't doing that, you aren't doing physics.

Edited March 9, 2015 by swansont
fix typo

[Robittybob1]

 

So now go to the next step and show how a ±4% change in the width affects convection, using some fluid flow equations, in support of your hypothesis. Then go from there.

 

If you aren't doing that, you aren't doing physics.

Where did you get your "±4% change in the width" from?

A 60 km displacement of a body that has a radius of 1220 km is around the 5% mark but that isn't the degree of change in the throat width, for the small object (IC) is blocking the OC which is a much more voluminous body. So my calculation of the ratio of the wide side to the narrow side was a maximum of 0.76% different.

 

The thermal gradient will be as low as 1 degree per km across the OC ( if the IC is centralised and the OC depth is around 2260 km and the temperature difference between the IC and OC is seldom estimated at more than 2000 degrees difference, so one would have to say the gradient is quite minimal considering the distance. It won't take much stirring to disrupt the thermal flows which such minimal gradients.

 

I will be looking at doing further calculations to see if my prediction is correct.

[swansont]

Where did you get your "±4% change in the width" from?

A 60 km displacement of a body that has a radius of 1220 km is around the 5% mark but that isn't the degree of change in the throat width, for the small object (IC) is blocking the OC which is a much more voluminous body. So my calculation of the ratio of the wide side to the narrow side was a maximum of 0.76% different.

 

Sorry, that should have been ±0.4%. From the 1.0077 value you gave. Comparing it to the radius of the inner core is meaningless. Convection doesn't happen there, it happens in the liquid.

 

The thermal gradient will be as low as 1 degree per km across the OC ( if the IC is centralised and the OC depth is around 2260 km and the temperature difference between the IC and OC is seldom estimated at more than 2000 degrees difference, so one would have to say the gradient is quite minimal considering the distance. It won't take much stirring to disrupt the thermal flows which such minimal gradients.

 

I will be looking at doing further calculations to see if my prediction is correct.

 

Yes, a calculation would be a welcome addition.

[Robittybob1]

 

Sorry, that should have been ±0.4%. From the 1.0077 value you gave. Comparing it to the radius of the inner core is meaningless. Convection doesn't happen there, it happens in the liquid.

 

 

Yes, a calculation would be a welcome addition.

An interesting comparison would be the surface area of the IC compared to surface area of the OC.

IC radius 1220 km

OC radius 2260 km

Sphere

surface area, A = 4 * π * r ^ 2

 

That calculates out that the OC has 3.43 times the surface area of the IC. So there could well be blobs of "cold" hence denser molten material that falls down through the OC gravitated to the IC. That would be a type of "reverse convection".

Work by Gary Glatzmaier has come up again. The Geodynamo! http://www.es.ucsc.edu/~glatz/geodynamo.html

 

In addition, about 36,000 years into the simulation the magnetic field underwent a reversal of its dipole moment (Figure 3), over a period of a little more than a thousand years. The intensity of the magnetic dipole moment decreased by about a factor of ten during the reversal and recovered immediately after, similar to what is seen in the Earth's paleomagnetic reversal record. Our solution shows how convection in the fluid outer core is continually trying to reverse the field but that the solid inner core inhibits magnetic reversals because the field in the inner core can only change on the much longer time scale of diffusion [2]. Only once in many attempts is a reversal successful, which is probably the reason why the times between reversals of the Earth's field are long and randomly distributed.

Wow did I understand that correctly? The magnetic field produced by the thermal convections is trying to reverse the magnetic field in the Inner Core! And it is the balance between the two that determines the overall polarity.

Edited March 10, 2015 by Robittybob1

[swansont]

 

That calculates out that the OC has 3.43 times the surface area of the IC. So there could well be blobs of "cold" hence denser molten material that falls down through the OC gravitated to the IC. That would be a type of "reverse convection".

 

No, that would be just regular old convection. Hot fluid rises, cool fluid sinks.

 

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heatra.html#c3

[Robittybob1]

 

No, that would be just regular old convection. Hot fluid rises, cool fluid sinks.

 

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heatra.html#c3

But does that mean it falls straight down or is it going to be affected by the Coriolis effect? If it was a metal it would at the very least be a conductor moving in a magnetic field. http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/genwir2.html

 

When a conductor moves through a magnetic field, there will be a generated motional emf. This is one example of Faraday's Law and it arises from the magnetic force. The voltage generated in a length of wire, presuming that the entire length moves through a uniform field, is given below.

Generated voltage = emf = Velocity x B-field x Length

Which hand do I use for that? It is interesting that velocity comes into that.

[swansont]

But does that mean it falls straight down or is it going to be affected by the Coriolis effect? If it was a metal it would at the very least be a conductor moving in a magnetic field. http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/genwir2.html

 

It's all part of what's going on. It's complicated.

Which hand do I use for that? It is interesting that velocity comes into that.

 

Right hand.

 

 

How about this: since you seemingly did not know the Lorentz force rule, or what convection actually entails, how about you ask questions about the physics basics or otherwise learn it before you propose some alternative? Then you might actually be able to include some physics in those proposals.

[Robittybob1]

 

It's all part of what's going on. It's complicated.

 

Right hand.

 

 

How about this: since you seemingly did not know the Lorentz force rule, or what convection actually entails, how about you ask questions about the physics basics or otherwise learn it before you propose some alternative? Then you might actually be able to include some physics in those proposals.

My hypothesis was dependent on the idea of a tidally displaced Inner Core. Did you ever answer my question as to whether you agreed with Martin Wolf that the IC could be displaced by up to 60 km? Trying to understand the dynamics of the Geodynamo is another matter all together.

 

Could you please tell the forum whether you agree with a tidally displaced IC?

[swansont]

My hypothesis was dependent on the idea of a tidally displaced Inner Core. Did you ever answer my question as to whether you agreed with Martin Wolf that the IC could be displaced by up to 60 km? Trying to understand the dynamics of the Geodynamo is another matter all together.

 

Could you please tell the forum whether you agree with a tidally displaced IC?

 

I don't think I've commented on that at all. It's largely irrelevant whether I agree with it or not. I am perfectly happy to provisionally accept it in the context of a model that connects it with the claim of the OP, but thus far you haven't made that connection or posted any sort of model — just a cryptic claim that, in effect, the data excludes your claim and yet you continue to assert that your idea has merit. Just unsupported claims and a lot of tap-dancing around the issue.

 

Frankly, I'm more than ready to close the thread for failure to comply with the speculations mandate for evidence and /or model.

[Robittybob1]

 

I don't think I've commented on that at all. It's largely irrelevant whether I agree with it or not. I am perfectly happy to provisionally accept it in the context of a model that connects it with the claim of the OP, but thus far you haven't made that connection or posted any sort of model — just a cryptic claim that, in effect, the data excludes your claim and yet you continue to assert that your idea has merit. Just unsupported claims and a lot of tap-dancing around the issue.

 

Frankly, I'm more than ready to close the thread for failure to comply with the speculations mandate for evidence and /or model.

I believe I have tried to build that model, but all along you have tried to deflect me into studying the geodynamo. If you don't want to commit to the idea is there anyone else who is in agreement with Martin Wolf?

It seems rather difficult to build a model showing that this displacement is part of what transfers momentum to the Moon unless you can accept that the tidal displacement occurs in the first place.

Edited March 10, 2015 by Robittybob1

[swansont]

I believe I have tried to build that model, but all along you have tried to deflect me into studying the geodynamo. If you don't want to commit to the idea is there anyone else who is in agreement with Martin Wolf?

 

You're the one who keeps bringing it up. I've asked how the earth's magnetic field can cause the moon to recede and you have delved into something that you agree is tidal in nature. I'm still waiting for the connection.

[Robittybob1]

 

You're the one who keeps bringing it up. I've asked how the earth's magnetic field can cause the moon to recede and you have delved into something that you agree is tidal in nature. I'm still waiting for the connection.

And I'm sure I've said it is not the magnetic field that does this but the same mechanism that produces the magnetic field contributes to this.

The title to the thread was not made up by me so don't use that as some sort of guide.

 

It all depends on the idea of a tidal displacement of the Earth's inner core. Unless one can decide whether to accept that idea or not there is no way I can develop the concept of using that displacement to move a metal conductor faster on one side of the IC. That is why I found the Lorenz's force law so interesting, for I have always thought of the moving OC molten metal as a current but it might be better to think of it in terms of a moving conductor in a magnetic field.

I agree and have admitted the full concept is not developed yet, and I'm still working on it. The forum debate keeps you on track.

Edited March 10, 2015 by Robittybob1

[swansont]

And I'm sure I've said it is not the magnetic field that does this but the same mechanism that produces the magnetic field contributes to this.

 

 

Which remains unexplained. Doubly so, as you reject the mainstream explanation of the field.

 

So, now that we've recapped, do you have any physics to post in support of this mechanism, which has no evidence to support its existence?

[Robittybob1]

 

Which remains unexplained. Doubly so, as you reject the mainstream explanation of the field.

 

So, now that we've recapped, do you have any physics to post in support of this mechanism, which has no evidence to support its existence?

I have not rejected that either. The physics in support of the mechanism depends on the tidally displaced IC and the math of that was dealt with by Martin Wolf. Once you can accept that idea the physics of the increased flow rate through the narrow side is supporting the concept that it will produce increased motion of a conductor (or a current) through a magnetic field.

The torque required to hold the IC in the displaced position transfers momentum to the Moon (as part of the tidal acceleration of the Moon).

So have you rejected the idea of the tidally displaced Inner Core by the words ".... this mechanism, which has no evidence to support its existence"? You don't seem to be making yourself very clear.

Edited March 10, 2015 by Robittybob1

[swansont]

I have not rejected that either. The physics in support of the mechanism depends on the tidally displaced IC and the math of that was dealt with by Martin Wolf. Once you can accept that idea the physics of the increased flow rate through the narrow side is supporting the concept that it will produce increased motion of a conductor (or a current) through a magnetic field.

No actual physics here. You point to a few concepts, but have presented no calculations, nor demonstrated that any effect that might be present is not already accounted for already. What's the change in flow rate? How is the field affected by this?

 

The torque required to hold the IC in the displaced position transfers momentum to the Moon (as part of the tidal acceleration of the Moon).

Again, there's no actual physics being done here. What torque? How big is it? Why is a torque required to hold the core in place?

 

So have you rejected the idea of the tidally displaced Inner Core by the words ".... this mechanism, which has no evidence to support its existence"? You don't seem to be making yourself very clear.

No, remember the context of the thread. I reject the slowing of the earth and displacement of the moon from this effect, since the data show that the angular momentum transfer is already accounted for, something you've already conceded.