# The Naked Scientists Forum

### Author Topic: Does Earth/Moon Model Show Cavendish Is Wrong?  (Read 7901 times)

#### common_sense_seeker

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##### Does Earth/Moon Model Show Cavendish Is Wrong?
« on: 26/09/2008 11:11:29 »
A scaled down version would have the Earth about the size of your eye and the Moon would be the size of a pea held at arms length. Even if they were made of everyday magnets there still wouldn't be enough attractive force to maintain an orbit. Let alone if they were made of rock or metal! The calculated value for big G is clearly wrong. Even the Wikipedia entry alludes to the fact that repeat experiments give highly varying values. Modern satellite technology is based on the measured surface gravity of the Earth and not the incorrectly calculated value of the gravitational constant. Hence Cavendish is wrong.

#### DrDick

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##### Does Earth/Moon Model Show Cavendish Is Wrong?
« Reply #1 on: 26/09/2008 14:13:50 »
But how are you accomplishing that scale-down?  You should realize that the size of the earth and moon vary as the cube of their radii.  Meaning  that if you make the earth one millionth its normal size, the mass decreases by a factor of 1018.  Doing the same to the moon results in a similar effect.  So, while the distance between the moon and the earth has decreased by a factor of 106, the force due to gravity has decreased by a factor of 1036.  That's 1,000,000,000,000,000,000,000,000,000,000 times the change of the distance.

Is it really any surprise that you might not see an effect?

#### lyner

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##### Does Earth/Moon Model Show Cavendish Is Wrong?
« Reply #2 on: 26/09/2008 15:23:02 »
I'm afraid that mere numbers are unlikely to convince css.

Using a magnetic analogy is a poor analogy. It is not viable because of the symmetry involved. Electric forces have the same geometry as gravity and are much much more powerful - enough to lift a piece of paper with a small charged comb and beating the gravitational attraction of the massive Earth. G is very small - but its measured value explains the motion of most astronomical bodies.

In any case, where is you evidence that G is hugely wrong? The dynamics of small and large scale systems all follow Newton's Laws very well if you use the measured values of G. What, exactly, is your alternative?

quote from Wikkers
"a value of G = 6.693 × 10−11 cubic meters per kilogram second squared, with a standard error of the mean of ±0.027 × 10−11 and a systematic error of ±0.021 × 10−11 cubic meters per kilogram second squared"
Does that represent a wild variation?

#### common_sense_seeker

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##### Does Earth/Moon Model Show Cavendish Is Wrong?
« Reply #3 on: 26/09/2008 15:28:49 »
The scaled down sizes were given as part of a BBC TV programme on Penzance beach on the day of the Solar Eclipse in the UK. The Sun was the size of a large beach ball, about 7ft high, and placed at the other end of the bay. When the pea is held at arms length against the distant beach ball, it is obscurred. This is a simulation of the eclipse and the relative sizes of the three bodies involved.

The relative masses compared against one another are conserved in the scale model.

#### DoctorBeaver

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##### Does Earth/Moon Model Show Cavendish Is Wrong?
« Reply #4 on: 26/09/2008 17:20:06 »
The other end of the bay? Somehow I doubt that as the bay is roughly 2 miles across!

« Last Edit: 26/09/2008 17:22:57 by DoctorBeaver »

#### common_sense_seeker

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##### Does Earth/Moon Model Show Cavendish Is Wrong?
« Reply #5 on: 27/09/2008 10:41:22 »
I saw it on TV! A far distance away, not necessarily the furthest point of the bay away. It was a great demonstration of relative sizes and distance separating the three bodies so explaining the solar eclipse perfectly for anyone to see.

#### common_sense_seeker

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##### Does Earth/Moon Model Show Cavendish Is Wrong?
« Reply #6 on: 27/09/2008 10:46:28 »
It's Cavendish's assumption of Newton's law with which he calculates the density of the Earth that is the problem. I'm working through it. I'm convinced that the basic assumption is wrong. I'll provide the maths to prove my alternative theory of Dark Matter At The Center Of The Earth as soon as I can.

#### Bored chemist

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##### Does Earth/Moon Model Show Cavendish Is Wrong?
« Reply #7 on: 27/09/2008 15:18:09 »
The sizes of the earth and moon are well established, as is the distance between them.
They tally perfectly well with the observed orbital period and the value of "G".
Scaling them down would, as Dr Dick pointed out, reduce the force between them so you wouldn't observe it easilly for a "model" of the size you are considering.
Howeve, Cavendish did the experiment on roughly the scale you are talking about (and many others have done it since) and it gives an answer that agrees with the prediction

Now CSS, since the accepted theory gives the right force, but your "theory" gives the wrong one, can you see why nobody is listening to your theory?

#### common_sense_seeker

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##### Does Earth/Moon Model Show Cavendish Is Wrong?
« Reply #8 on: 30/09/2008 10:13:13 »
BC, I accept the scale model provides the given values. But I am convinced that Cavendish's assumption of Newton's law of gravitation has led to an over estimate of the Earth's mass. If one assumes that the inner core has a higher force of gravitational attraction, based on the Hapgood mammoth data, the maths still pans out accordingly. The implications of this are enormous, since the masses of the Moon and Sun are based on this calculation. It suggests that solar masses are also over estimates, which begins to negate the need for DM to explain galaxies in the traditional sense.

If you accept it as a possiblity, it increasingly looks more and more likely.

#### Bored chemist

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##### Does Earth/Moon Model Show Cavendish Is Wrong?
« Reply #9 on: 30/09/2008 19:52:27 »
"If one assumes that the inner core has a higher force of gravitational attraction"
Or, one can look at the evidence and say that we know what the earth weighs based on observations of satellites and such.
If you assume that there are fairies at the bottom of the garden then all sorts of thing becoem possible, that's exactly why you shouldn't make outlandish assumptions.

"If you accept it as a possiblity, it increasingly looks more and more likely. "
If you accept that I am God then it is overwhelmingly likely that I'm right.
Of course, it's a dumb thing to accept since there's not a shred of evidence for it.

#### lyner

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##### Does Earth/Moon Model Show Cavendish Is Wrong?
« Reply #10 on: 01/10/2008 00:17:48 »
Quote
, it increasingly looks more and more likely.

"looks" implies that there is some evidence. Where is it?
Show us. Give us a reference. Tell us the true values.
We are all agog, waiting for the revelation.

#### common_sense_seeker

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##### Does Earth/Moon Model Show Cavendish Is Wrong?
« Reply #11 on: 01/10/2008 13:18:24 »
I'm doing the maths proof now. It's going better than expected. A few people on another forum have said that "I'm onto something". You two will never be convinced I'm sure. You'll be like the flat-earth society of tomorrow.

#### Bored chemist

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##### Does Earth/Moon Model Show Cavendish Is Wrong?
« Reply #12 on: 01/10/2008 19:59:59 »
Are you sure they didn't say "Your on something"?
Perhaps you would like to include a link (ie some evidence- a factor that has been conspicuous by its absence from your posts)

#### lyner

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##### Does Earth/Moon Model Show Cavendish Is Wrong?
« Reply #13 on: 03/10/2008 00:06:50 »
I'm doing the maths proof now. It's going better than expected. A few people on another forum have said that "I'm onto something". You two will never be convinced I'm sure. You'll be like the flat-earth society of tomorrow.
I can hardly wait for the proof. Will it be based on standard Maths or a new quasimaths?

#### Bored chemist

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##### Does Earth/Moon Model Show Cavendish Is Wrong?
« Reply #14 on: 03/10/2008 07:09:53 »

#### Bored chemist

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##### Does Earth/Moon Model Show Cavendish Is Wrong?
« Reply #15 on: 11/11/2008 07:00:12 »
Do you think that has anything to do with the thread?
It reminds me of an old joke, the original version went something like this..
At a dinner party some bloke says "I have never seen any scientific proof of the existence of God"
The Priest looks at him and says, sagely "Ah, yes, but I have never seen a theological proof of the existence of atoms.

OK that was the original.
At any dinner party I was at the next line would be "I have never seen a theological proof of anything."
We all know that Science deals with things that can (at least in principle) be proved.
God simply isn't in that category.

So what is it about the God squad that makes them think it's acceptable to ressurect a thread like this and talk about subjecting God to scientific analysis?

How would it look if I interupted the vitally important thread on some theology site (perhaps discussing how many angels can dance on the head of a pin) and pointed out that you can't use nuclear physics to predict the weather?
Would it look like a valuable contribution?
What about "The average Englishman's penis weighs about twice as much as the average American's does"?
It's true enough but does it help in any way?

Incidentally, provided that the largest angel can dance on the head of a pin, given time, all the angels can dance on the head of a pin.
Just not at the same time.

« Last Edit: 11/11/2008 20:00:39 by Bored chemist »

#### johnbrandy

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##### Does Earth/Moon Model Show Cavendish Is Wrong?
« Reply #16 on: 13/11/2008 00:32:08 »
Re: Bored chemist, your comments are correct. I intended to post my comments within the thread, "Scientific Proof of God". I cannot explain this mistake. I apologize and take responsibility for this error. I will delete my inappropriate entry, and seek to understand my oversight. I appreciate your consistently informed and enlightened contributions to this forum. Thank you.

#### Bored chemist

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##### Does Earth/Moon Model Show Cavendish Is Wrong?
« Reply #17 on: 13/11/2008 06:56:36 »
Fair enough, we all make mistakes.
Having said that, I think the " proof of God" thread has run its course already.

#### The Naked Scientists Forum

##### Does Earth/Moon Model Show Cavendish Is Wrong?
« Reply #17 on: 13/11/2008 06:56:36 »