toldailytopic: How old is the earth?

[NotSamHarris]

To young earth creationists: What sort of things would make you question your belief of the age of the earth? What kind of things would you expect to see on a very old earth?

 

[voltaire]

BArbarian. You say that the tidal frequency was less when the moons gratitational pull was greater due to keplers laws and the resulting period of the moons orbit. You are inplying that greater tidal frequency equals greater recessional speed. you do realize that recessional speed is a function of tidal force?

 

[voltaire]

Im going to ask you a series of leading questions barbarian. The tidal bulge leads the moon correct? Does this lead increase whth greater rotational speed of the earth?

 

[Stripe]

Models are not evidence.

...unless they are built out of accepted assumptions. If you build a model for a proposed physical system using accepted physical limits and conditions then the model does become evidence. So you could tell us which part of Dr. Brown's model is in error then you would actually be contributing to the discussion. Instead you seem to be relying solely upon your ability to divide and your make believe debate with an unheard of creationist.

Anytime you have anything of actual relevance... :up:

And when we do the math, we get billions of years.

1.2 billion. To be exact.

But you need a lot more than that. So please show us the mathematical model to describe what you're talking about. :up:

Barbarian chuckles: Let's leave it at 4.0 cm/year, just to give you the benefit of a doubt and to ease calculation. The Roche Limit (distance from the Earth at which the moon would break up from gravitational forces) is about 9,500 km. The moon is presently about 384,000 km away. So, the present rate of recession (which as I said, changes over geologic time) would suggest 9.6 billion years to reach it's present place from the Roche limit. Pick a different distance, and I'll calculate the time for you as well. And then we can see what the tides were at that time. Not bad for doing it in my head. The actual calculated value is...9,362,500,000 years. Well, you could do the math yourself. But if you don't know how, I'll do it for you: 384,000 km - 9,500km = 374,500 km. Or about 37,450,000,000 cm. Divide by 4 cm/year, you get 9,362,500,000 years since the moon would have been at the Roche limit.

1.2 billion years. You should quit pretending you can do this stuff in your head.

Well, at least you aren't calling me an atheist this time.

When have I ever called you an atheist?

http://www.talkorigins.org/faqs/moonrec/tide-friction.jpg

Talk Origins is junk on this issue. Here's why:

The ocean bulge is pulled in front of the moon by Earth's spin; since the ocean is gravitationally stuck to the Earth, it has to go where the Earth goes. But it can't go too far, because it is pulled back by the moon. The result, illustrated in figure 3, is that the ocean bulge is in equilibrium, remaining essentially fixed with respect to the Earth and moon, while the solid Earth spins under the ocean. The ocean is gravitationally bound to the Earth, but it is still fluid, and not stuck to the Earth the way a rock or a mountain is. There is an interface, namely the ocean bottom, where the water and the Earth are free to move with respect to each other. That interface, like any other real physical interface, is not totally frictionless, and that too is illustrated in figure 3 by the small caption that reads "Friction force". But in this case, "friction" includes all of the ways that the ocean and the Earth impede each other. The ocean runs into the continents and has to wash around them (so how they are distributed around the Earth makes a difference).

This is all utter fluff. The Earth cannot slow down because of friction on the floor of the ocean any more than it slows down because of friction at any other given surface layer.

There is nothing special about the Earth's oceans that will affect the model I provided.

When TO says, "The ocean is gravitationally bound to the Earth, but it is still fluid, and not stuck to the Earth the way a rock or a mountain is" they are raising an unnecessary complication. A rock or a mountain is affected in the same way as an ocean is and energy is transferred in the same manner.

A mountain on the Earth is attracted by the moon. That attraction provides the mountain with energy to move against the spin of the Earth. This energy provided is the same as is provided to the same mass of ocean water. The rest of the Earth then has to overcome that friction created. It will require the same amount of energy for the earth to overcome the mountain's friction as it will to overcome the friction from the same mass of ocean water.

The only important thing is the mass that is displaced. With water the mass displacement is great. With a mountain it is very small. When the water is displaced that tidal bulge affects the moon. Friction on Earth is completely irrelevant.

Even with two rocky bodies orbiting each other we would see the same physical process in action. But the bulges created would be very tiny and thus the recession rates very small.

So this is all fluff.

Since the Earth is trying to spin forward, but the ocean is held back by the moon, the Earth winds up trying to move through the oceans. Just as you can feel the resistance if you try to walk through water, so the Earth feels the resistance trying to move through the water of the oceans, and that resistance transfers energy from the Earth (causing its spin rate to slow), and to the oceans (sloshing them around and heating them up).

That was all fluff.

I notice you left out this part:

Later researchers came to the conclusion that Jeffreys had rather severely underestimated the true numerical value for oceanic tidal dissipation, and had therefore overestimated the age of the Earth-moon system. Although they do not offer an age, Munk & McDonald (1960) said that Jeffreys had the oceanic dissipation wrong by a factor of 100. It soon became apparent that the pendulum had swung the other way, and that there was a fundamental problem. Slichter (1963) reanalyzed the Earth-moon torque by devising a new way to use the entire ellipsoid of Earth rather than treating it as a series of approximations. He decided that, depending on the specifics of the model, the moon would have started out very close to Earth anywhere from 1.4 billion to 2.3 billion years ago, rather than 4.5 billion years ago. Slichter remarked that if "for some unknown reason" the tidal torque was much less in the past than in the present (where "present" means roughly the last 100 million years), this would solve the problem. But he could not supply the reason, and concluded his paper by saying that the time scale of the Earth-moon system "still presents a major problem"; I call this "Slichter's dilemma".

Worried that someone else came to something like 1.2 billion years without including certain assumptions, Barbie?

Instead you jump to this...

The years that followed saw the rise of plate tectonics and a major shift in geophysical thinking because of it. The mobility of the drifting continents is a matter of major import, for by this time it was well realized that tidal dissipation in shallow seas dominated the interaction between Earth and the moon.

...which is what I was talking about. In order to reject the model and evidence I linked to one is forced to assume rather dramatic alterations to the Earth.

Now, I'm not sure what you are arguing here. You seem to be trying to paint this model I provided as wrong. It's not. That admission is made in your very link. The numbers are valid and the working is correct. So in order to reject the model you have to assert something else. You have to first assume the truth of some more old earth ideas.

Fact is that the physics dictate moon recession had to be faster in the past. But you insist it was slower.

I think I'll stick with the physics thanks. :up:

 

[voltaire]

Stripe. You do realize that TO is onto the same point im making? It just gives false mechanics to the situation. The tidal bulge does work against the earths rotation but the energy transfer is instantaneous and ends up slowding down the earth.

 

[Stripe]

Stripe. You do realize that TO is onto the same point im making? It just gives false mechanics to the situation. The tidal bulge does work against the earths rotation but the energy transfer is instantaneous and ends up slowding down the earth.

They (TO and Barbie) need moon recession to have been slower in the past - contrary to the physics involved. I'm not entirely sure how they achieve that .. something to do with plate tectonics.

Seems pretty simple to me. The moon's recession rate will always decrease with time. That seems perfectly intuitive and is backed up by the physics in my link.

 

[The Barbarian]

Barbarian corrects Stipe:
Models are not evidence.

...unless they are built out of accepted assumptions.

Nope. You can't "accept" your assumptions, and then call them evidence. Sorry.

If you build a model for a proposed physical system using accepted physical limits and conditions then the model does become evidence. So you could tell us which part of Dr. Brown's model is in error then you would actually be contributing to the discussion. Instead you seem to be relying solely upon your ability to divide and your make believe debate with an unheard of creationist.

I don't think generic insults will help you, Stipe.

And when we do the math, we get billions of years.
1.2 billion. To be exact.

But you need a lot more than that.

The fact is, 1.2 billion is more than enough to destroy the YE "model."

Barbarian chuckles: Let's leave it at 4.0 cm/year, just to give you the benefit of a doubt and to ease calculation. The Roche Limit (distance from the Earth at which the moon would break up from gravitational forces) is about 9,500 km. The moon is presently about 384,000 km away. So, the present rate of recession (which as I said, changes over geologic time) would suggest 9.6 billion years to reach it's present place from the Roche limit. Pick a different distance, and I'll calculate the time for you as well. And then we can see what the tides were at that time. Not bad for doing it in my head. The actual calculated value is...9,362,500,000 years. Well, you could do the math yourself. But if you don't know how, I'll do it for you: 384,000 km - 9,500km = 374,500 km. Or about 37,450,000,000 cm. Divide by 4 cm/year, you get 9,362,500,000
years since the moon would have been at the Roche limit.

1.2 billion years.

You should quit pretending you can do this stuff in your head.

Well, it was a small multiplication error. Perhaps you don't know that a kilometer has 100,000 centimeters. I assumed you knew.

Barbarian notes:
http://www.talkorigins.org/faqs/moon...e-friction.jpg

Talk Origins is junk on this issue.

It's pretty straightforward physics. And the geological evidence supports it. And Tim Thompson happens to be an astrophysicist of some note, who knows what he's talking about. And of course your curriculum vitae and work experience in astrophysics is...?

The ocean bulge is pulled in front of the moon by Earth's spin
since the ocean is gravitationally stuck to the Earth, it has to go where the Earth goes. But it can't go too far, because it is pulled back by the moon. The result, illustrated in figure 3, is that the ocean bulge is in equilibrium, remaining essentially fixed with respect to the Earth and moon, while the solid Earth spins under the ocean. The ocean is gravitationally bound to the Earth, but it is still fluid, and not stuck to the Earth the way a rock or a mountain is. There is an interface, namely the ocean bottom, where the water and the Earth are free to move with respect to each other. That interface, like any other real physical interface, is not totally frictionless, and that too is illustrated in figure 3 by the small caption that reads "Friction force". But in this case, "friction" includes all of the ways that the ocean and the Earth impede each other. The ocean runs into the continents and has to wash around them (so how they are distributed around the Earth makes a difference).

This is all utter fluff. The Earth cannot slow down because of friction on the floor of the ocean any more than it slows down because of friction at any other given surface layer.

It can, and does. Friction takes kinetic energy and converts it to heat and other forms of energy. That reduced kinetic energy slows the Earth. That's how it works, Stipe.

There is nothing special about the Earth's oceans that will affect the model I provided.

Nothing in the real world will affect your model.

When TO says, "The ocean is gravitationally bound to the Earth, but it is still fluid, and not stuck to the Earth the way a rock or a mountain is" they are raising an unnecessary complication.

For creationists, the real world is an "unnecessary complication." It is the tides that slow the Earth and cause the moon's recession.

A rock or a mountain is affected in the same way as an ocean is and energy is transferred in the same manner.

A mountain on the Earth is attracted by the moon. That attraction provides the mountain with energy to move against the spin of the Earth. This energy provided is the same as is provided to the same mass of ocean water. The rest of the Earth then has to overcome that friction created. It will require the same amount of energy for the earth to overcome the mountain's friction as it will to overcome the friction from the same mass of ocean water.

Something has to move to cause "friction."

Even with two rocky bodies orbiting each other we would see the same physical process in action. But the bulges created would be very tiny and thus the recession rates very small.

But with oceans that are both fluid and substantial, the recession rates are significant.

Now, I'm not sure what you are arguing here. You seem to be trying to paint this model I provided as wrong. It's not.

Of course the Earth isn't 9 billion years old. What I'm showing you, is that your model, if actually applied to the real world, would give you over 9 billion years.

Fact is that the physics dictate moon recession had to be faster in the past. But you insist it was slower.

That's what the evidence shows, Stipe.

Geological constraints on the Precambrian history of Earth's rotation and the Moon's orbit
Williams, George E.
Reviews of Geophysics, Volume 38, Issue 1, p. 37-60 (

Abstract
Over the past decade the analysis of sedimentary cyclic rhythmites of tidal origin, i.e., stacked thin beds or laminae usually of sandstone, siltstone, and mudstone that display periodic variations in thickness reflecting a strong tidal influence on sedimentation, has provided information on Earth's paleorotation and the evolving lunar orbit for Precambrian time (before 540 Ma). Depositional environments of tidal rhythmites range from estuarine to tidal delta, with a wave-protected, distal ebb tidal delta setting being particularly favorable for the deposition and preservation of long, detailed rhythmite records. The potential sediment load of nearshore tidal currents and the effectiveness of the tide as an agent of sediment entrainment and deposition are related directly to tidal range (or maximum tidal height) and consequent current speed. Hence the thickness of successive laminae deposited by tidal currents can be a proxy tidal record, with paleotidal and paleorotational values being determined by analysis of measured records of lamina and cycle thickness. The validity of the findings can be investigated by testing the primary, observed values for internal self-consistency through application of the laws of celestial mechanics. Paleotidal and paleorotational values provided by late Neoproterozoic (~620 Ma) tidal rhythmites in South Australia are validated by these tests and indicate 13.1+/-0.1 synodic (lunar) months/yr, 400+/-7 solar days/yr, a length of day of 21.9+/-0.4h, and a relative Earth-Moon distance a/a0 of 0.965+/-0.005. The mean rate of lunar recession since that time is 2.17+/-0.31cm/yr, which is little more than half the present rate of lunar recession of 3.82+/-0.07cm/yr obtained by lunar laser ranging. The late Neoproterozoic data militate against significant overall change in Earth's moment of inertia and radius at least since 620 Ma. Cyclicity displayed by Paleoproterozoic (2450 Ma) banded iron formation in Western Australia may record tidal influences on the discharge and/or dispersal of submarine hydrothermal plumes and suggests 14.5+/-0.5 synodic months/yr and a/a0=0.906+/-0.029. The combined rhythmite data give a mean rate of lunar recession of 1.24+/-0.71cm/yr during most of the Proterozoic (2450-620 Ma), suggesting that a close approach of the Moon did not occur during earlier time. Concentrated study of Precambrian tidal rhythmites promises to illuminate the evolving dynamics of the early Earth-Moon system and may permit the lunar orbit to be traced back to near the time of the Moon's origin.

I think I'll stick with the physics thanks.

You and physics aren't living in the same zip code, Stipe.

 

[Stripe]

Nope. You can't "accept" your assumptions, and then call them evidence. Sorry.

When you find someone who says this then you can tell them off for doing so. :up:

I don't think generic insults will help you, Stipe.

I don't think I used any insults. Could you point them out to me?

The fact is, 1.2 billion is more than enough to destroy the YE "model."

That's a maximum age, Barbie. Try to keep up. :up:

Well, it was a small multiplication error. Perhaps you don't know that a kilometer has 100,000 centimeters. I assumed you knew.

You continue on as if you're providing some kind of useful analysis. Multiplying out at the current recession rate is an all but useless calculation.

It can, and does. Friction takes kinetic energy and converts it to heat and other forms of energy. That reduced kinetic energy slows the Earth. That's how it works, Stipe.

TO is just plain fluff. The ocean is the Earth for all intents and purposes. Just as any mountain or rock is. The only thing that is of any relevance is the mass displacement.

You can't look at friction between the ocean and the seafloor as an influence any more than you can look at friction between a mountain and the earth's crust as an influence.

Nothing in the real world will affect your model.

You have posted nothing that even indicates you've read the page I linked to so I think we can safely ignore your assessment.

It is the tides that slow the Earth and cause the moon's recession.

Uh huh. And it matters not one iota what friction is going on in those tides. All that matters is the amount of mass that is displaced.

Something has to move to cause "friction."

Force has to be applied to cause friction. If the force is not great enough to overcome friction then no movement will occur. And your implication is wrong. Mountains and rocks do move in response to tidal factors. How do you think we generate earthquakes?

But with oceans that are both fluid and substantial, the recession rates are significant.

Because of the mass displaced. Not because of any friction.

Of course the Earth isn't 9 billion years old. What I'm showing you, is that your model, if actually applied to the real world, would give you over 9 billion years.

Try reading the link I provided. :thumb:

That's what the evidence shows, Stipe.

No, it doesn't.

 

[The Barbarian]

(Barbarian corrects Stipe)
Models are not evidence.

Stipe disagrees:
...unless they are built out of accepted assumptions.

Barbarian chuckles:
Nope. You can't "accept" your assumptions, and then call them evidence. Sorry.

When you find someone who says this then you can tell them off for doing so.

Just did, Stiipe. Did you forget what you wrote?

You continue on as if you're providing some kind of useful analysis. Multiplying out at the current recession rate is an all but useless calculation.

How fast do you think it was, Stipe. And show us your evidence and numbers? Oh, and it has to be consistent with the geological evidence.

Barbarian observes:
The fact is, 1.2 billion is more than enough to destroy the YE "model."

That's a maximum age, Barbie.

One-thousandth of that age is enough to destroy the YE "model." You telling us that recession was a thousand times faster in the past, and then suddenly slowed down by Roman times when people were watching?

Try to keep up.

Your imagination is always out ahea of us, Stipe.

Barbarian observes:
Well, it was a small multiplication error. Perhaps you don't know that a kilometer has 100,000 centimeters. I assumed you knew.

You continue on as if you're providing some kind of useful analysis. Multiplying out at the current recession rate is an all but useless calculation.

It puts an order of magnitude on the problem. And it shows that no possible rate of recession could be consistent with YE creationism.

Barbarian observes:
It can, and does. Friction takes kinetic energy and converts it to heat and other forms of energy. That reduced kinetic energy slows the Earth. That's how it works, Stipe.

TO is just plain fluff. The ocean is the Earth for all intents and purposes. Just as any mountain or rock is. The only thing that is of any relevance is the mass displacement.

Tim Thompson is an astrophyscist. He actually knows how it works. And your qualifications are...?

You can't look at friction between the ocean and the seafloor as an influence any more than you can look at friction between a mountain and the earth's crust as an influence.

Actually, you can. Here's an experiment someone accidentally tried:
Put a water bed in a Volkswagen microbus. Then go take some corners. Let me know how it turns out.

Barbarian chuckles:
Nothing in the real world will affect your "model."

Barbarian observes:
It is the tides that slow the Earth and cause the moon's recession.

Uh huh. And it matters not one iota what friction is going on in those tides. All that matters is the amount of mass that is displaced.

Sorry, that's wrong. If there was no frictional force between the Earth and it's oceans, the Earth would simply rotate under the tidal bulge and no energy would be transferred at all.

Barbarian notes:
Something has to move to cause "friction."

Force has to be applied to cause friction.

If something moves.

And your implication is wrong. Mountains and rocks do move in response to tidal factors. How do you think we generate earthquakes?

Convection currents in the Earth's mantle. You didn't know that? You think the Moon causes Earthquakes? Seriously, Stipe? :chuckle:

Barbarian observes:
That's what the evidence shows, Stipe.

No, it doesn't.

Denial won't help you. At this point, you need some evidence. And supposing the moon causes earthquakes is moving in the wrong direction. Your imagination, untethered by reality, is leading you off into another fairytale.

 

[Stripe]

(Barbarian corrects Stipe)
Models are not evidence. Stipe disagrees: ...unless they are built out of accepted assumptions. Barbarian chuckles: Nope. You can't "accept" your assumptions, and then call them evidence. Sorry. Just did, Stiipe. Did you forget what you wrote?

No, I knew what I had written. Models can be used as evidence. You are trying to accuse me of using an assumption as evidence.

I have assumptions. You're free to accept them or reject them. But if I build a model with those assumptions that describes reality accurately and is predictive then that model is evidence for the veracity of my assumptions.

That's what scientists do, Barbie.

You need to stop leaping to the conclusion that people have said something wrong and think things through a bit more. :up:

How fast do you think it was, Stipe. And show us your evidence and numbers?

How about you read the link I posted?

Oh, and it has to be consistent with the geological evidence.

Uh .. are you nuts? There is no way you could use geology to provide evidence for this. Perhaps you could interpret geology according to the model you've employed, but the physics dictate reality here.

One-thousandth of that age is enough to destroy the YE "model." You telling us that recession was a thousand times faster in the past, and then suddenly slowed down by Roman times when people were watching? It puts an order of magnitude on the problem. And it shows that no possible rate of recession could be consistent with YE creationism.

I think you need to think this through a bit more carefully, Barbie. 1.2 billion years is a maximum age derived from a valid physical model of the earth-moon system. Your multiplication ability shows your multiplication ability.

A maximum age means that the earth-moon system could have been initiated at any time less than 1.2 billion years ago and from that point it would have receded (according to the model provided) to today's state.

It can, and does. Friction takes kinetic energy and converts it to heat and other forms of energy. That reduced kinetic energy slows the Earth. That's how it works, Stipe.

If you are standing on a yacht and blow into the sail, are you aiding forward momentum?

Tim Thompson is an astrophyscist. He actually knows how it works. And your qualifications are...?

Dr. Walt Brown is an engineer. He knows how things work too. And your qualifications are?

Actually, you can. Here's an experiment someone accidentally tried: Put a water bed in a Volkswagen microbus. Then go take some corners. Let me know how it turns out.

Your car will fall over with enough speed in a corner because of the mass that is displaced and gravity. To talk about friction in this "accidental experiment" would be meaningless.

Sorry, that's wrong. If there was no frictional force between the Earth and it's oceans, the Earth would simply rotate under the tidal bulge and no energy would be transferred at all.

Your straw man is wrong. There is friction at work on and in the earth. But that friction has nothing to do with slowing the rotation of the earth. In the same way as friction is involved in the "accidental experiment". Friction is at work, but it is not the reason the V-Dub falls over.

The earth is slowed because of the gravitation environment created when there is a tidal bulge for the moon to act upon. Friction need not apply.

Convection currents in the Earth's mantle. You didn't know that? You think the Moon causes Earthquakes? Seriously, Stipe? :chuckle:

Yes, it does.

Seriously.

You think rock can convect? Seriously Barbie?

At this point, you need some evidence.

You should go and read it. :up:

And supposing the moon causes earthquakes is moving in the wrong direction.

Yeah, that's a very interesting tangent. Feel free to stay on topic though.

 

[voltaire]

Barbarian. Friction between ocean and the earth is not the reason why the moon gains angular momentum. It gains angular momentum because the moon pulls on the displaced tidal bulge. It pulls on that bulge regardless if there is friction or not.

 

[voltaire]

When there is a tidal bulge that is not directly under the moon, the moon is pulled in the direction of that bulge because it is closer to the moon than the rest of the mass of earth.

 

[voltaire]

I f the tidal bulge were not displaced, it would still create friction as it washed around the shores of continents. This would not slow down the rotation. It would simply dissipate in heat.

 

[voltaire]

If the earth was a smooth greased ball bearing with 2 miles of ocean on top, the moon would still gain angular momentum due to the pull on the displaced tidal bulge.

 

[The Barbarian]

No, I knew what I had written. Models can be used as evidence. You are trying to accuse me of using an assumption as evidence.

Models that are built on assumptions that contradict observable evidence are simply wrong.

That's what scientists do, Barbie.

Guess how I know you aren't a scientist.

Barbarian suggests:
How fast do you think it was, Stipe. And show us your evidence and numbers?

How about you read the link I posted?

If you don't understand it well enough to discuss it, what makes you think it's right?

Barbarian observes:
Oh, and it has to be consistent with the geological evidence.

Uh .. are you nuts? There is no way you could use geology to provide evidence for this.

Well, let's take a look...

Late Precambrian tidal rhythmites in South Australia and the history of the Earth's rotation
G. E. WILLIAMS

Department of Geology and Geophysics, University of Adelaide, GPO Box 498, Adelaide, South Australia 5001, Australia

Sedimentary rhythmites of siltstone and fine sandstone from late Precambrian (c. 650–800 Ma) glaciogenic formations in South Australia are interpreted as distal ebb-tidal deposits that record variability in the velocity and range of palaeo-ebb tides. Variations in lamina thickness encode a full spectrum of palaeotidal cycles, including semidiurnal, diurnal, fortnightly and monthly tidal cycles as well as the lunar apsides (perigee) and nodal cycles. A half-yearly oscillation is attributable largely to a beat between the fortnightly tidal cycles of luni-solar conjunction and lunar declination; the lunar nodal cycle is discernible as an amplitude modulation of this beat oscillation. The data allow determination of the Earth's palaeorotation and the past dynamics of the Earth-Moon system with an accuracy previously unattainable for the Precambrian. The late Precambrian (c. 650 Ma) year contained 13.1 (±0.5) lunar months and c. 400 (±20) days, and the late Precambrian lunar month c. 30.5 (±1.5) days. These values suggest an average equivalent phase lag near 3° since late Precambrian time rather than the present value of 6°. The period of 19.5 (±0.5) years determined for the lunar nodal cycle c. 650 Ma ago indicates a lunar distance 96.9 (±1.7)% of the present distance. The low rate of lunar recession since late Precambrian time revealed by the rhythmite data militates against a close approach of the Moon during the Proterozoic. Precambrian sedimentary rhythmites may hold a key to the early history of the Earth's rotation.

So, you're stuffed with prunes about that, too...

The Role of Tidal-Velocity Asymmetries in the Deposition of Silty Tidal Rhythmites (Carboniferous, Eastern Interior Coal Basin, U.S.A.)
Allen W. Archer (1), Gerald J. Kuec
Journal of Sedimentary Research
Volume 65a (1995)

ABSTRACT

Laminated to thin-bedded siltstones directly overlie Carboniferous coals at several localities in the Eastern Interior Coal Basin. Because lamina thicknesses show cyclical variations, the siltstones have been termed "tidal rhythmites". The rhythmites commonly show a repetitive thick-thin pairing of the laminae, and these two-lamina rhythmites have been interpreted as the result of the asymmetry of flood and ebb velocities that affected sedimentation in a diurnal paleotidal system. Alternatively, the pairing has been interpreted to be related to a pronounced difference in height between successive high tides in a semidiurnal system. This explanation suggests deposition in a mixed, predominately semidiurnal system with a marked diurnal inequality. In addition to the two-lamina rhythmite described originally, subsequent examination of drill cores indicates the occurrence of relatively rare, more complex three- and four-lamina rhythmites.

A variety of mathematical techniques are used herein to analyze lamina thickness data extracted from these rhythmites. Processing techniques include: (1) comparing the linear relationship between the thicknesses of the thinner and thicker laminae and comparing these relationships to modern tidal systems; (2) analyses of thickness periodicities and comparison with modern neap-spring tidal cycles; and (3) extraction of lamina thickness inequalities and comparison to the diurnal inequalities that occur in semidiurnal tidal systems. These tests indicate that reasonable conclusions can be made for the type of originating paleotidal system. For the cases analyzed herein, the paleotidal signature suggests a mixed, predominantly semidiurnal system with a marked diurnal inequality.

Perhaps you could interpret geology according to the model you've employed, but the physics dictate reality here.

I posted a nice explanation of the system from a real astrophysicist, not your jackleg creationist.

Barbarian observes:
One-thousandth of that age is enough to destroy the YE "model."
You telling us that recession was a thousand times faster in the past, and then suddenly slowed down by Roman times when people were watching? It puts an order of magnitude on the problem. And it shows that no possible rate of recession could be consistent with YE creationism.

I think you need to think this through a bit more carefully, Barbie.

As you learned, extrapolation is a dangerous thing. The argument your guy presented, if applied using actual physics, gives about 9 billion years of moon recession, assuming it started at the Roche limit.

1.2 billion years is a maximum age derived from a valid physical model of the earth-moon system.

But as you learned, we have physical evidence of the frequency of tides for very ancient times, and it doesn't fit your "model."

Barbarian observes:
It can, and does. Friction takes kinetic energy and converts it to heat and other forms of energy. That reduced kinetic energy slows the Earth. That's how it works, Stipe.

If you are standing on a yacht and blow into the sail, are you aiding forward momentum?

That's another reason your "model" won't work. You might think that would work, but there's a perfectly good reason it won't. Newton's third law says that the force on the sail (minus whatever losses occur) is the same as the force exerted on your mouth, and thereby on the deck. So it cancels out. A creationist might imagine he can cool off his house by opening the door of his refrigerator, but it doesn't work that way.

Tim Thompson is an astrophysicist. He actually knows how it works. And your qualifications are...?

I teach physics. And I know how it works. And you don't.

Dr. Walt Brown is an engineer.

Not an astrophysicist. Does that suggest to you why real astrophysicists don't agree with him?

He knows how things work too.

Sorry, he's got it completely wrong. But then he's an engineer, not a physicist.

And your qualifications are?

When I was taking mechanics (the branch of physics that deals with this stuff), I had to actually derive the equations. If you'll check with engineering schools, you'll find that most engineering students don't.

On the notion that the tides don't actually cause more force than a solid body:
Actually, you can. Here's an experiment someone accidentally tried: Put a water bed in a Volkswagen microbus. Then go take some corners. Let me know how it turns out.

Your car will fall over with enough speed in a corner

Bingo. Now explain to us what magical effect keeps that force from operating on the Earth.

Barbarian chuckles:
Sorry, that's wrong. If there was no frictional force between the Earth and it's oceans, the Earth would simply rotate under the tidal bulge and no energy would be transferred at all.

Your straw man is wrong.

It's a fact. No frictional force (which in this case includes water sloshing against shorelines), not force.

There is friction at work on and in the earth. But that friction has nothing to do with slowing the rotation of the earth.

Astrophysicists have demonstrated that it does.

(Stipe suggests that the Moon produced earthquakes)

Barbarian chuckles:
Convection currents in the Earth's mantle. You didn't know that? You think the Moon causes Earthquakes? Seriously, Stipe?

Yes, it does.

:nono:

You think rock can convect?

When it's hot enough to be fluid, it can. You don't know that layers of the mantle are fluid? How do you think plate tectonics works?

Seriously Barbie?

Yep. Learn about it, here...
http://mediatheek.thinkquest.nl/~ll125/en/mantle.htm

It's a lot more complicated that that simplified explanation might suggest, but heat from radioactive decay in the core works its way up, melts the mantle, and the hot magma rises through the cooler upper layers, putting pressure on the plates of the crust.

Slab pull at subduction zones probably has an effect as well, but this is ultimately also caused by convection.

Barbarian observes:
At this point, you need some evidence.

You should go and read it.

It's an old story. And it hasn't gotten any more accurate for being old.

(Barbarian chuckles at Stipe's claim that the moon causes earthquakes)

Yeah, that's a very interesting tangent. Feel free to stay on topic though.

Every now, and then Stipe comes up with something so monumentally bone-headed that it's worth noting. That was one of them. Geological processes cause earthquakes, but drillers injecting mud into a hole have been noted to have set off minor earthquakes by reducing the force at a fault to a level that would let the pent-up force release. The moon could do that, I suppose, but that would be like saying the force of your finger on a button could send a missile into space.

 

[The Barbarian]

I f the tidal bulge were not displaced, it would still create friction as it washed around the shores of continents. This would not slow down the rotation. It would simply dissipate in heat.

From where ,in your opinion, would the energy being lost as heat have come? It's not magic. Has to be taken from somewhere.

From what energy was the heat produced?

 

[voltaire]

Barbarian asks from what energy would the heat come from that was produced. The heat comes from friction of waves crashing against the shore. The waves are caused by the tidal bulge. The tidal bulge is cause by gravitational pull of the moon. Answer----- gravitational potential energy.

 

[The Barbarian]

Barbarian asks from what energy would the heat come from that was produced. The heat comes from friction of waves crashing against the shore.

There's a problem with that. On a non-rotating planet, the moon would cause a tidal bulge, and that would be that. No more motion, no additional energy.

But the rotation of the Earth causes the bulge to "crash against the shore" as it moves under the bulge. That's from where the energy comes. The kinetic energy of the earth rotating. And that energy is lost in the form of heat, slowing the Earth.

The waves are caused by the tidal bulge.

No. It's by the Earth rotating under the tidal bulge. If you were correct, we could build a perpetual motion machine running off the moon's gravity, and we could power satellites by using the much stronger gravity of the earth to operate generators.

But it doesn't work that way. No magic. Do you now see why tides slow the earth's rotation?

 

[WizardofOz]

Have we figured out how old the earth is yet?

Just checking.

 

[The Barbarian]

Have we figured out how old the earth is yet?

Yes, since 1956.

Patterson, Claire (1956). "Age of meteorites and the earth". Geochimica et Cosmochimica Acta 10 (4): 230–237. doi:10.1016/0016-7037(56)90036-9.