The Flat Earth Society

Flat Earth Discussion Boards => Flat Earth Debate => Topic started by: clydedaferret on August 23, 2008, 08:47:55 PM

Title: Gravitational field of earth
Post by: clydedaferret on August 23, 2008, 08:47:55 PM
Could someone please explain this to me?

Q: "If the Earth was indeed a flat disc, wouldn't the whole planet crunch up into itself and eventually transform into a ball?"

A1: If the Earth generated a gravitational field, yes, it would eventually happen, after a billion years maybe. FE assumes that the Earth does not generate a gravitational field.  What we know as 'gravity' is provided by the acceleration of the earth.

This is from the FAQ. This makes no sense. All matter (anything having mass) generates a gravitational field, even you and me. This was proved by the Cavendish experiment. I also performed this experiment in a college class.

How does the earth magically not generate a gravitational field?
Title: Re: Gravitational field of earth
Post by: Parsifal on August 23, 2008, 08:49:08 PM
This is a good question. I personally feel a FE model with a rotating earth exhibiting gravitation is more likely, but I'd be interested to hear the opinions of those FEers who think the Earth does not have a gravitational field.
Title: Re: Gravitational field of earth
Post by: Robbyj on August 23, 2008, 08:56:20 PM
Cavendish is not an experiment showcasing gravity, only torsion of a rod or wire.
Title: Re: Gravitational field of earth
Post by: clydedaferret on August 23, 2008, 09:16:40 PM
Robbyj, the Cavendish experiment IS meant to showcase gravity. The Cavendish experiment, done in 1797 – 1798 by Henry Cavendish, was the first experiment to measure the force of gravity between masses in the laboratory.
Title: Re: Gravitational field of earth
Post by: Robbyj on August 23, 2008, 09:17:15 PM
It did nothing of the sort.
Title: Re: Gravitational field of earth
Post by: clydedaferret on August 23, 2008, 09:26:17 PM
What the hell are you talking about? The point of the experiment was to show everything produces a force on other objects due to its gravitational field! Hell, he was able to determine the gravitational constant for god sakes.
Title: Re: Gravitational field of earth
Post by: Jack on August 23, 2008, 09:26:31 PM
Robbyj, the Cavendish experiment IS meant to showcase gravity. The Cavendish experiment, done in 1797 – 1798 by Henry Cavendish, was the first experiment to measure the force of gravity between masses in the laboratory.
No, it only tried to measure the density of the Earth and perhaps predicted G.
Title: Re: Gravitational field of earth
Post by: cbreiling on August 23, 2008, 09:27:32 PM
Cavendish is not an expirement showcasing gravity, only torsion of a rod or wire.

It is not true that the experiment showcases torsion, although minimizing torsion is a very important part of the apparatus. Building a device that has near-zero torsion is critical because the force of gravity movement along geodesics due to small masses is incredibly small. You can do the experiment yourself. (http://www.fourmilab.ch/gravitation/foobar/)

When you compare multi-mass systems you are literally bending spacetime, as defined by Einstein. (In the Cavendish experiment, you are moving the position of masses, thus manually bending spacetime.) Einstein also said that for non-extreme cases this is proportional to the masses involved.

Sure, gravity doesn't exist. But large masses such as the Earth (flat or round) bend spacetime significantly, causing a lot of motion along geodesics.

For some reason, many FE folks who hold Einstein up as the messiah of spacetime, in their zeal to deny gravity, insist that the Earth's mass have no effect on spacetime whatsoever.  ???
Title: Re: Gravitational field of earth
Post by: clydedaferret on August 23, 2008, 09:29:24 PM
Robbyj, the Cavendish experiment IS meant to showcase gravity. The Cavendish experiment, done in 1797 – 1798 by Henry Cavendish, was the first experiment to measure the force of gravity between masses in the laboratory.
No, it only predicted G.

Yes! Which used the fact that all objects exert forces on others by their gravitational fields!
Title: Re: Gravitational field of earth
Post by: Jack on August 23, 2008, 09:30:36 PM
Gravitational constant != force of gravity. The experiment did not prove gravity.
Title: Re: Gravitational field of earth
Post by: Robbyj on August 23, 2008, 09:31:08 PM
Robbyj, the Cavendish experiment IS meant to showcase gravity. The Cavendish experiment, done in 1797 – 1798 by Henry Cavendish, was the first experiment to measure the force of gravity between masses in the laboratory.
No, it only predicted G.

Yes! Which used the fact that all objects exert forces on others by their gravitational fields!

Not in the least.
Title: Re: Gravitational field of earth
Post by: clydedaferret on August 23, 2008, 09:31:44 PM
Without the force of gravity, the experiment wouldn't make any sense.
Title: Re: Gravitational field of earth
Post by: Robbyj on August 23, 2008, 09:33:23 PM
It seems that we are in agreeance.
Title: Re: Gravitational field of earth
Post by: clydedaferret on August 23, 2008, 09:34:23 PM
No, we aren't. I conducted the experiment myself. There is clearly an attractive force between objects.

Also:
The gravitational constant, denoted G, is a physical constant involved in the calculation of the gravitational attraction between objects with mass.
Title: Re: Gravitational field of earth
Post by: Jack on August 23, 2008, 09:35:17 PM
Also:
The gravitational constant, denoted G, is a physical constant involved in the calculation of the gravitational attraction between objects with mass.
Right, so how does that equal to gravity itself?
Title: Re: Gravitational field of earth
Post by: clydedaferret on August 23, 2008, 09:36:52 PM
I never said it did. All I am saying is that the experiment helped produce that constant which is used to calculate the force due to gravitational forces between two (or more) objects.
Title: Re: Gravitational field of earth
Post by: Jack on August 23, 2008, 09:39:59 PM
All I am saying is that the experiment helped produce that constant which is used to calculate the force due to gravitational forces between two (or more) objects.
So you admit that you were wrong about the experiment earlier?
Title: Re: Gravitational field of earth
Post by: Robbyj on August 23, 2008, 09:40:29 PM
which is used to calculate the force due to gravitational forces between two (or more) objects.

Oh really?
Title: Re: Gravitational field of earth
Post by: clydedaferret on August 23, 2008, 09:42:29 PM
What? How would that be admitting I am wrong. I am not wrong.
Title: Re: Gravitational field of earth
Post by: clydedaferret on August 23, 2008, 09:44:11 PM
According to the law of universal gravitation, the attractive force (F) between two bodies is proportional to the product of their masses (m1 and m2), and inversely proportional to the square of the distance (r) between them:

    F = G \frac{m_1 m_2}{r^2}.
Title: Re: Gravitational field of earth
Post by: Jack on August 23, 2008, 09:45:36 PM
What? How would that be admitting I am wrong. I am not wrong.
This,
the Cavendish experiment IS meant to showcase gravity.

Title: Re: Gravitational field of earth
Post by: Robbyj on August 23, 2008, 09:49:14 PM
According to the law of universal gravitation, the attractive force (F) between two bodies is proportional to the product of their masses (m1 and m2), and inversely proportional to the square of the distance (r) between them:

    F = G \frac{m_1 m_2}{r^2}.

Ok, now use your equation to calculate the force between the sun and a photon.
Title: Re: Gravitational field of earth
Post by: cbarnett97 on August 23, 2008, 10:55:06 PM
According to the law of universal gravitation, the attractive force (F) between two bodies is proportional to the product of their masses (m1 and m2), and inversely proportional to the square of the distance (r) between them:

    F = G \frac{m_1 m_2}{r^2}.
replace m_2 with the equation (hf)/c^2 where h is plancks constant f is the frequency of the photon and c is of course the speen of light and then you can go ahead an calculate the force between the 2 objects

Ok, now use your equation to calculate the force between the sun and a photon.]
Title: Re: Gravitational field of earth
Post by: zork on August 24, 2008, 12:52:19 AM
What? How would that be admitting I am wrong. I am not wrong.
This,
the Cavendish experiment IS meant to showcase gravity.
You use the words gravity and gravitation in your FAQ and don't do so exact distinction between then. If you are so precise about their use then put the definition of "gravity" and "gravitation" on your FAQ
Title: Re: Gravitational field of earth
Post by: Jack on August 24, 2008, 01:23:11 AM
There is a sticky that defines "gravity" and "gravitation".
Title: Re: Gravitational field of earth
Post by: zork on August 24, 2008, 02:22:32 AM
According to the law of universal gravitation, the attractive force (F) between two bodies is proportional to the product of their masses (m1 and m2), and inversely proportional to the square of the distance (r) between them:

    F = G \frac{m_1 m_2}{r^2}.

Ok, now use your equation to calculate the force between the sun and a photon.
Be a little more consistent please. In the sticky Gravity thread there is your message last where you state - Photons are massless, you can only calculate momentum.
 This equation requires both bodies mass, in your case sun and photon. So, are you stating now that photons have mass?
Title: Re: Gravitational field of earth
Post by: Jack on August 24, 2008, 02:25:59 AM
No, he is proving that the Newtonian equation becomes invalid in explaining the world events, due to its inconsistency with some phenomenons. For example, gravitational lensing.
Title: Re: Gravitational field of earth
Post by: zork on August 24, 2008, 02:37:56 AM
No, he is proving that the Newtonian equation becomes invalid in explaining the world events, due to its inconsistency with some phenomenons. For example, gravitational lensing.
Just how does he proves that when he requires to calculate something which needs mass and provides one component of equation without mass?
Title: Re: Gravitational field of earth
Post by: Jack on August 24, 2008, 02:54:35 AM
Just how does he proves that when he requires to calculate something which needs mass and provides one component of equation without mass?
He isn't requiring anything. He knows photons are massless, and the law of universal gravitation cannot solve for massless particles. That's why he is asking for a value as a way to prove the person, who brought up the equation earlier, wrong. Get the point?
Title: Re: Gravitational field of earth
Post by: zork on August 24, 2008, 06:28:41 AM
Just how does he proves that when he requires to calculate something which needs mass and provides one component of equation without mass?
He isn't requiring anything. He knows photons are massless, and the law of universal gravitation cannot solve for massless particles. That's why he is asking for a value as a way to prove the person, who brought up the equation earlier, wrong. Get the point?
Yes, he requires to calculate something with formula which isn't meant to calculate it. Formula quite simply states that two masses are needed. And photon doesn't have mass as he itself says. It's like I give you the only one object and require you to calculate gravitational attraction between this one object and nothing. So, no I don't get the point.
Title: Re: Gravitational field of earth
Post by: Jack on August 24, 2008, 06:56:57 AM
Yes, he requires to calculate something with formula which isn't meant to calculate it. Formula quite simply states that two masses are needed. And photon doesn't have mass as he itself says. It's like I give you the only one object and require you to calculate gravitational attraction between this one object and nothing. So, no I don't get the point.
(sigh) I'll make this simple: he is basically trying to say the formula is incomplete. You seem to be having a hard time inferring his point.
Title: Re: Gravitational field of earth
Post by: zork on August 24, 2008, 08:52:53 AM
(sigh) I'll make this simple: he is basically trying to say the formula is incomplete. You seem to be having a hard time inferring his point.
(sigh) Point is, formula is for one thing and it works for it. What the use is saying that formula doesn't do what I want when I don't give it all parameters or when I put it in situation which isn't correct for it. You don't use quite same physical formulas on normal events and on quantum events or when scales are universe versus atoms and electrons. So yes, you can say I have hard time getting to the point.
Title: Re: Gravitational field of earth
Post by: divito the truthist on August 24, 2008, 09:01:00 AM
zork, are you being obtuse on purpose?
Title: Re: Gravitational field of earth
Post by: zork on August 24, 2008, 09:17:07 AM
zork, are you being obtuse on purpose?
No, I just live on round earth and have a hard time to get to the point presented by people living on flat earth.
Title: Re: Gravitational field of earth
Post by: divito the truthist on August 24, 2008, 09:24:21 AM
You think you live on a spherical Earth. Anyways, the point of Robbyj's post is to showcase the insufficiency, and in blatant terms, incorrectness of Newton's version of gravitation.
Title: Re: Gravitational field of earth
Post by: cbreiling on August 24, 2008, 11:35:26 AM
This is a great example of the obfuscation by introducing the red herring:

First Clydeaferret gives the law of universal gravitation:
According to the law of universal gravitation, the attractive force (F) between two bodies is proportional to the product of their masses (m1 and m2), and inversely proportional to the square of the distance (r) between them:

    F = G \frac{m_1 m_2}{r^2}.

Then Robbyj whips out the red herring (http://www.nizkor.org/features/fallacies/red-herring.html):
Ok, now use your equation to calculate the force between the sun and a photon.

Yeah, talking about photons is a great way of ignoring the usefulness of the law of universal gravitation.  ::)

A few posts later:
No, he is proving that the Newtonian equation becomes invalid in explaining the world events, due to its inconsistency with some phenomenons. For example, gravitational lensing.

This is great. Gravitational Lensing (http://imagine.gsfc.nasa.gov/docs/features/news/grav_lens.html) is now a "world event" making Newtonian equations invalid. Did anyone pick up on the fact that the title of this thread is "the gravitational field of Earth"? Some posters here are carrying the FET torch that Newtonian equations are invalid because they break down under extreme circumstances which don't routinely occur on Earth or in our solar system.

If the debaters stuck to purely solar system mechanics (or as the OP intended, gravitational field of Earth), then there really isn't a whole lot to talk about with regards to whether gravity affects photons, as happens in gravitational lensing.
Title: Re: Gravitational field of earth
Post by: Jack on August 24, 2008, 11:42:56 AM
Quote
Yeah, talking about photons is a great way of ignoring the usefulness of the law of universal gravitation.
That's the whole point.
Title: Re: Gravitational field of earth
Post by: Roundy the Truthinessist on August 25, 2008, 12:33:34 PM
This is a great example of the obfuscation by introducing the red herring:

First Clydeaferret gives the law of universal gravitation:
According to the law of universal gravitation, the attractive force (F) between two bodies is proportional to the product of their masses (m1 and m2), and inversely proportional to the square of the distance (r) between them:

    F = G \frac{m_1 m_2}{r^2}.

Then Robbyj whips out the red herring (http://www.nizkor.org/features/fallacies/red-herring.html):
Ok, now use your equation to calculate the force between the sun and a photon.

Yeah, talking about photons is a great way of ignoring the usefulness of the law of universal gravitation.  ::)

Okay, nobody here disputes the usefulness of Newton's laws of gravity.  We are only disputing his correctness.  He was wrong about there being a force.  He was wrong about gravity, whether the equations work in most cases or not; it only takes one example where they don't work out to prove that they are fundamentally wrong.

But nobody disputes that his equations can be useful.  Please quit with the straw men.  ::)
Title: Re: Gravitational field of earth
Post by: Josef on August 25, 2008, 01:12:59 PM
This is a good question. I personally feel a FE model with a rotating earth exhibiting gravitation is more likely, but I'd be interested to hear the opinions of those FEers who think the Earth does not have a gravitational field.

How fast do you think the earth is rotating? Relative to the solarearthsystem.
Title: Re: Gravitational field of earth
Post by: cbreiling on August 25, 2008, 08:57:00 PM
Okay, nobody here disputes the usefulness of Newton's laws of gravity.
Excuuuuuze me?  :) Newton's law of gravity is the most heavily-slandered piece of science here on the Flat Earth Forums. Mostly it takes the form of "gravity doesn't exist." Frequently anyone who dares suggest that behaviors of objects in Earth's gravitation can be perfectly described by F=Gm1m2/r2 is promptly pilloried because "Gravity isn't a force," and because objects fall towards Earth with an acceleration of 9.8 m/s/s because the Earth and Universe are doing the UA zoom "to infinity... and beyond!"

I'd say this counts as "disputing the usefulness of Newton's laws."

I know perfectly well that Einstein's equations are necessary for calculating high-energy stuff like black holes and gravitational lensing, yadda yadda, but you can't beat an algebra equation for describing routine real-world phenomena like trajectories and bouncing balls, versus the tensor calculus needed for Einstein's stuff.

From the University of New South Wales in Sydney, comes this discussion (http://www.phys.unsw.edu.au/~jw/gravity.html#limits) of the limitations of Newton:
Quote
Although [Newton's theory of Universal Gravitation] is an excellent theory, it does not agree with experiment if one investigates extremely large fields, or moderately large fields with very high precision. In other words, it is wrong. However, it is such an excellent approximation that Newtonian gravity is what we use to calculate in almost all circumstances, while recognising that it is just a very convenient approximation to more exact theories.

There's a good reason why every gravity problem in an engineering textbook can be correctly solved using algebra (plus trig and calculus), even if using by Einstein's formulas and tensors you'll get the same answers, to a very high degree of precision. That reason is that Newton's equations are useful, even if they've been eclipsed by more-accurate ones from Einstein.

We are only disputing his correctness.

You conveniently forget that several planets were discovered mathematically using Newton's equations. When you write of "disputing correctness" exactly how many digits of precision do you want when calculating things here on earth, like the apparent force of gravity exerted by a Zetetic Armchair? Why don't Flat Earthers propose dropping the "Universal" from the name Newton's Law of Universal Gravitation? The formula still works for 99% of real-world applications outside high-energy physics.

But nobody disputes that his equations can be useful. Please quit with the straw men.  ::)

 ??? Name the author of the quote: "He was wrong about there being a force. He was wrong about gravity, whether the equations work in most cases or not; it only takes one example where they don't work out to prove that they are fundamentally wrong." That was none other than Roundy the Truthinessist!  :P "Nobody disputes" indeed!

Dude, you need some glasses.  :) Almost every Flat Earther on these boards disputes the usefulness of Newton's equations, simply because then they'd have to admit that the entire Flat Earth must have no mass.

Boo-yah.
Title: Re: Gravitational field of earth
Post by: Roundy the Truthinessist on August 25, 2008, 08:59:04 PM
You're just wrong about this, and I think you completely misunderstood what I was saying.  Newton was wrong about gravity, however useful his equations might be.  Sorry you can't grasp that concept.
Title: Re: Gravitational field of earth
Post by: cbreiling on August 25, 2008, 09:15:16 PM
You're just wrong about this, and I think you completely misunderstood what I was saying.  Newton was wrong about gravity, however useful his equations might be.  Sorry you can't grasp that concept.

You could claim "humans are wrong about breathing" (you know that universal law where it says you breathe in, breathe out, and you stay alive).

It works 99.9% of the time, but it doesn't work underwater or in a smoke-filled room (unless it's ganja), so I propose that everyone here who thinKs "breathing is fundamentally wrong" should stop immediately.

Do I have to tell you esteemed dudes fifty freaking times that I know that there is no force of gravity, it's all just space-time bendy geodesics? I get it already! I'm still sticking with Newton, and I still believe the Earth has mass.  :P

Having said all that, sorry if I misunderstood your meaning.
Title: Re: Gravitational field of earth
Post by: Parsifal on August 25, 2008, 10:06:47 PM
How fast do you think the earth is rotating?

Rotation is not a relative concept, and the Earth is rotating once every 23 minutes 56 seconds, or with an angular velocity of 7.3 * 10-5 s-1.
Title: Re: Gravitational field of earth
Post by: cbreiling on August 25, 2008, 11:12:52 PM
...angular velocity of 7.3 * 10-5 s-1.

Watch those units, Steve. You used "hertz" above.  :) (Lame attempt at busting chops.)
Title: Re: Gravitational field of earth
Post by: Parsifal on August 25, 2008, 11:14:42 PM
...angular velocity of 7.3 * 10-5 s-1.

Watch those units, Steve. You used "hertz" above.  :) (Lame attempt at busting chops.)

That is the correct unit for angular velocity.
Title: Re: Gravitational field of earth
Post by: Jack on August 25, 2008, 11:35:32 PM
It works 99.9% of the time
Keep posting this number; it just shows how unsophisticated you are.
Title: Re: Gravitational field of earth
Post by: Josef on August 26, 2008, 12:40:42 AM
Rotation is not a relative concept, and the Earth is rotating once every 23 minutes 56 seconds, or with an angular velocity of 7.3 * 10-5 s-1.

That is sweet. What about the centripetal force? The FE radius and speed must give a lot of that force near the edges.

I see two paths.
The first one is that the rotation itself causes "gravity", that somehow cancels out the centripetal force.

The second one is that earth is concave. That explains why water isnt dragged out to the edges. And why youre not "pulled" straight down with "gravity", but also sideways, making it feel that earth is tilting. 

I like the earth being concave (CE! hehe). But it means that light has to be even more bent than on FE.

Im not trying to prove anything, just want to excerice those lazy grays.
Title: Re: Gravitational field of earth
Post by: Parsifal on August 26, 2008, 02:09:36 AM
That is sweet. What about the centripetal force? The FE radius and speed must give a lot of that force near the edges.

I see two paths.
The first one is that the rotation itself causes "gravity", that somehow cancels out the centripetal force.

The second one is that earth is concave. That explains why water isnt dragged out to the edges. And why youre not "pulled" straight down with "gravity", but also sideways, making it feel that earth is tilting. 

I like the earth being concave (CE! hehe). But it means that light has to be even more bent than on FE.

Im not trying to prove anything, just want to excerice those lazy grays.

It is my view that the Earth's gravitation cancels out the centripetal force.
Title: Re: Gravitational field of earth
Post by: divito the truthist on August 26, 2008, 04:35:27 AM
You could claim "humans are wrong about breathing" (you know that universal law where it says you breathe in, breathe out, and you stay alive).

It works 99.9% of the time, but it doesn't work underwater or in a smoke-filled room (unless it's ganja), so I propose that everyone here who thinKs "breathing is fundamentally wrong" should stop immediately.

If you had actually read what Roundy posted, he never said that we can't use Newton's equations, but that for some things (like breathing) it doesn't work.
Title: Re: Gravitational field of earth
Post by: Dr Matrix on August 26, 2008, 04:41:46 AM
If the centripetal force were cancelled by the Earth's gravitation then wouldn't that require a gradual changing of Fg (where I set this to be the vector describing the force due to gravitation) such that the angle it meets the surface changes uniformly with latitude from the North Pole to the Ice Wall? Such an explanation would require a peculiar distribution of mass in the FE and would not prevent the FE from collapsing into a sphere under its own gravitation.

There are other rotation-based issues with FE as well which are not fixed by a rotating plane/disc, such as relativistic frame dragging and the geodetic effect - the results of experiments measuring these phenomena would disagree with predictions made for a rotating sphere. Additionally, a rotating FE does not explain the lower value of g (as in, the observed acceleration due to gravitation) at the equator, which in RE is due to the centrifugal pseudo-force.  Does FE have any explanation for these phenomena?
Title: Re: Gravitational field of earth
Post by: Josef on August 26, 2008, 10:56:46 AM
It is my view that the Earth's gravitation cancels out the centripetal force.

Is there a model from that theory around here somewhere?
Otherwise it would be cool if someone created one. Using the proposed centripetal force as basis (?).
Title: Re: Gravitational field of earth
Post by: Lubbocks on August 26, 2008, 03:00:58 PM
Why are we arguing about gravity?  It seems that the Flat Earthers want us to prove that gravity exists in order to prove that the Earth is a sphere.  Gravity is a phenomena which we all experience our whole lives, but has properties which physicists have difficulty explaining.  I’m sure that some of you have seen the PBS shows on modern physics which describes some of these issues.  There are also several very good books that you can read.  Just Google search “Modern Physics”.  My point is, why do we have to prove anything about gravity in order to prove that the earth is a sphere?  We don’t.  We have pictures from space.  We have satellites which orbit around the earth.  Your claim that the earth is flat is so ridiculous that I don’t really think that you are being serious.
Title: Re: Gravitational field of earth
Post by: Sir_Drainsalot on August 26, 2008, 03:04:06 PM
Why are we arguing about gravity?  It seems that the Flat Earthers want us to prove that gravity exists in order to prove that the Earth is a sphere.  Gravity is a phenomena which we all experience our whole lives, but has properties which physicists have difficulty explaining.  I’m sure that some of you have seen the PBS shows on modern physics which describes some of these issues.  There are also several very good books that you can read.  Just Google search “Modern Physics”.  My point is, why do we have to prove anything about gravity in order to prove that the earth is a sphere?  We don’t.  We have pictures from space.  We have satellites which orbit around the earth.  Your claim that the earth is flat is so ridiculous that I don’t really think that you are being serious.

Gravity doesnt exist, duh  ::)
Title: Re: Gravitational field of earth
Post by: Hammod on August 26, 2008, 03:06:15 PM
Why are we arguing about gravity?  It seems that the Flat Earthers want us to prove that gravity exists in order to prove that the Earth is a sphere.  Gravity is a phenomena which we all experience our whole lives, but has properties which physicists have difficulty explaining.  I’m sure that some of you have seen the PBS shows on modern physics which describes some of these issues.  There are also several very good books that you can read.  Just Google search “Modern Physics”.  My point is, why do we have to prove anything about gravity in order to prove that the earth is a sphere?  We don’t.  We have pictures from space.  We have satellites which orbit around the earth.  Your claim that the earth is flat is so ridiculous that I don’t really think that you are being serious.
I'm sure if you stick around long enough, someone will show you that cheese is proof that the earth is flat.  ;D
Stick around - it's funny
Title: Re: Gravitational field of earth
Post by: cbreiling on August 26, 2008, 05:29:58 PM
...angular velocity of 7.3 * 10-5 s-1.

Watch those units, Steve. You used "hertz" above.  :) (Lame attempt at busting chops.)

That is the correct unit for angular velocity.

Dude, you're supposed to be the physics student! The units of angular velocity are "degrees per second" not "per second" (hertz) as you wrote.  :)

It works 99.9% of the time
Keep posting this number; it just shows how unsophisticated you are.

Sorry Marshal, I meant to write 99.89372. That's much more sophisticated.  :P

As for gravity / gravitation / motion along geodesics... What's the mass of the Earth in FET? (I'm honestly curious, and it's not meant as a rhetorical question.)

Title: Re: Gravitational field of earth
Post by: Parsifal on August 26, 2008, 08:13:20 PM
...angular velocity of 7.3 * 10-5 s-1.

Watch those units, Steve. You used "hertz" above.  :) (Lame attempt at busting chops.)

That is the correct unit for angular velocity.

Dude, you're supposed to be the physics student! The units of angular velocity are "degrees per second" not "per second" (hertz) as you wrote.  :)

I am a physics student, yes. That is how I know that I used the correct unit for angular velocity.
Title: Re: Gravitational field of earth
Post by: niceguybut on August 27, 2008, 05:50:40 AM
...angular velocity of 7.3 * 10-5 s-1.

Watch those units, Steve. You used "hertz" above.  :) (Lame attempt at busting chops.)

That is the correct unit for angular velocity.

Dude, you're supposed to be the physics student! The units of angular velocity are "degrees per second" not "per second" (hertz) as you wrote.  :)

I am a physics student, yes. That is how I know that I used the correct unit for angular velocity.

The SI unit is radians per second (http://en.wikipedia.org/wiki/Radians_per_second), but can also be converted to other units such as Hz, where 1 rad/s = 1/2π Hz

Moving swiftly along...
Title: Re: Gravitational field of earth
Post by: mayhem on August 27, 2008, 07:20:55 AM
That is sweet. What about the centripetal force? The FE radius and speed must give a lot of that force near the edges.

I see two paths.
The first one is that the rotation itself causes "gravity", that somehow cancels out the centripetal force.

The second one is that earth is concave. That explains why water isnt dragged out to the edges. And why youre not "pulled" straight down with "gravity", but also sideways, making it feel that earth is tilting. 

I like the earth being concave (CE! hehe). But it means that light has to be even more bent than on FE.

Im not trying to prove anything, just want to excerice those lazy grays.

It is my view that the Earth's gravitation cancels out the centripetal force.

Can you please explain how?  I'm trying to picture this in my mind's eye...the gravitation effect is pulling us essentially straight down towards the earth, but wouldn't the centripetal force of the rotating earth be at 90 degrees to the gravitational force?  I'm not sure I understand how this could cancel out...in order or that to work out, wouldn't the forces need to be 180 out of phase like noise cancelling headphone use counternoise sinewaves to cancel out noice sine waves?

This is the first time I've noticed any FE indication that the earth is rotating...usually the models presented have the spotlight-sun moving in some sort of ellipse above the surface of the earth...any rotation brings into play a force that works at a right angle to the gravitational effect we feel (or the continuous acceleration that our minds perceive as gravitation).  I'm genuinely curious about any information and/or explanation that you may put forth.
Title: Re: Gravitational field of earth
Post by: Dr Matrix on August 27, 2008, 07:45:41 AM
If the centripetal force were cancelled by the Earth's gravitation then wouldn't that require a gradual changing of Fg (where I set this to be the vector describing the force due to gravitation) such that the angle it meets the surface changes uniformly with latitude from the North Pole to the Ice Wall? Such an explanation would require a peculiar distribution of mass in the FE and would not prevent the FE from collapsing into a sphere under its own gravitation.

There are other rotation-based issues with FE as well which are not fixed by a rotating plane/disc, such as relativistic frame dragging and the geodetic effect - the results of experiments measuring these phenomena would disagree with predictions made for a rotating sphere. Additionally, a rotating FE does not explain the lower value of g (as in, the observed acceleration due to gravitation) at the equator, which in RE is due to the centrifugal pseudo-force.  Does FE have any explanation for these phenomena?
Title: Re: Gravitational field of earth
Post by: Jack on August 27, 2008, 07:46:49 AM
Sorry Marshal, I meant to write 99.89372. That's much more sophisticated.  :P
Right, so how did you get this number?
Title: Re: Gravitational field of earth
Post by: cbreiling on August 27, 2008, 12:50:15 PM
Sorry Marshal, I meant to write 99.89372. That's much more sophisticated.  :P
Right, so how did you get this number?

I made it up. See, first I took the orbital data of Mercury, Venus, Earth, Luna, Mars, Deimos Phobos, Ceres, Jupiter, Io, Europa, Ganymede, Callisto, Saturn, Titan, Uranus, Neptune, Triton, and Pluto for the period of one year. Then I selected 53 of the most well-known artificial satellites in Earth Orbit, including the Hubble and the ISS. I then compared each set of orbital observational data with what would be predicted by Newton's equations.

The result was so far over 99.99% that I figured you wouldn't believe me, so I picked a number that was really large, but realistically off, using a bit of psychology. All very scientific.
Title: Re: Gravitational field of earth
Post by: mayhem on August 27, 2008, 12:54:30 PM
Please show your work.   ;D
Title: Re: Gravitational field of earth
Post by: cbreiling on August 27, 2008, 12:59:33 PM
Please show your work.   ;D

I did it in my head. I also count spilled toothpicks (http://www.imdb.com/title/tt0095953/).
Title: Re: Gravitational field of earth
Post by: Dr Matrix on August 27, 2008, 03:55:17 PM
Glad to see you're finally realising how this site works, cbreiling ;D
Title: Re: Gravitational field of earth
Post by: Jack on August 27, 2008, 04:49:12 PM
I made it up.
That's where you are wrong.
Title: Re: Gravitational field of earth
Post by: cbreiling on August 27, 2008, 05:00:41 PM
I made it up.
That's where you are wrong.

Prove it.
Title: Re: Gravitational field of earth
Post by: Jack on August 27, 2008, 05:14:34 PM
It's already proven. You made it up, but that doesn't mean it's true.
Title: Re: Gravitational field of earth
Post by: cbreiling on August 27, 2008, 08:30:51 PM
It's already proven. You made it up, but that doesn't mean it's true.

I remain skeptical of your "proof." I want to see data.
Title: Re: Gravitational field of earth
Post by: Jack on August 27, 2008, 08:37:30 PM
Read,

Quote
You made it up, but that doesn't mean it's true.

It's a philosophical way of questioning your credibility. Of course, you claimed that the number is made up. Why should anyone accept or believe in something made up by you? Are you an expert in the relevant field?


What makes you more credible than anyone else such that your claims should be accepted?
Title: Re: Gravitational field of earth
Post by: interstellarsphere on August 27, 2008, 09:57:05 PM
Could someone please explain this to me?

Q: "If the Earth was indeed a flat disc, wouldn't the whole planet crunch up into itself and eventually transform into a ball?"

A1: If the Earth generated a gravitational field, yes, it would eventually happen, after a billion years maybe. FE assumes that the Earth does not generate a gravitational field.  What we know as 'gravity' is provided by the acceleration of the earth.

This is from the FAQ. This makes no sense. All matter (anything having mass) generates a gravitational field, even you and me. This was proved by the Cavendish experiment. I also performed this experiment in a college class.

How does the earth magically not generate a gravitational field?

The simple answer is FE is indeed wrong. Everything with mass generates a gravitational fiel directlly prportional to its mass  (mre mass = more spacial disruption = more gravity ) This is why water  droplets all form perfect spheres on Earth.
Title: Re: Gravitational field of earth
Post by: sokarul on August 27, 2008, 11:51:16 PM
...angular velocity of 7.3 * 10-5 s-1.

Watch those units, Steve. You used "hertz" above.  :) (Lame attempt at busting chops.)

That is the correct unit for angular velocity.

Dude, you're supposed to be the physics student! The units of angular velocity are "degrees per second" not "per second" (hertz) as you wrote.  :)

I am a physics student, yes. That is how I know that I used the correct unit for angular velocity.

When you steal numbers you should quote them. 

http://hypertextbook.com/facts/2002/JasonAtkins.shtml (http://hypertextbook.com/facts/2002/JasonAtkins.shtml)
Title: Re: Gravitational field of earth
Post by: Parsifal on August 28, 2008, 01:10:41 AM
The SI unit is radians per second (http://en.wikipedia.org/wiki/Radians_per_second), but can also be converted to other units such as Hz, where 1 rad/s = 1/2π Hz

A radian is a pure number, since it corresponds to a metre of arc per metre radius, or metres per metre. Thus, the unit I used (s-1) is equivalent to radians per second.

When you steal numbers you should quote them. 

http://hypertextbook.com/facts/2002/JasonAtkins.shtml (http://hypertextbook.com/facts/2002/JasonAtkins.shtml)

Just because you can't convert 23 hours 56 minutes into seconds and invert it with a calculator doesn't mean nobody can.
Title: Re: Gravitational field of earth
Post by: sokarul on August 28, 2008, 08:12:23 AM

Just because you can't convert 23 hours 56 minutes into seconds and invert it with a calculator doesn't mean nobody can.
We all know you didn't do it. 
Title: Re: Gravitational field of earth
Post by: Parsifal on August 28, 2008, 08:18:45 AM
We all know you didn't do it. 

What does it matter? You're derailing the thread by drawing attention to the fact that you don't think I pressed a few buttons on a calculator to perform a calculation that any high school student should be able to do. No more of this, please; stay on topic.
Title: Re: Gravitational field of earth
Post by: Jack on August 28, 2008, 08:20:14 AM
Seriously, no more derailments.

I'm still waiting for cbreiling to post more of his stories.
Title: Re: Gravitational field of earth
Post by: mayhem on August 28, 2008, 10:11:38 AM
That is sweet. What about the centripetal force? The FE radius and speed must give a lot of that force near the edges.

I see two paths.
The first one is that the rotation itself causes "gravity", that somehow cancels out the centripetal force.

The second one is that earth is concave. That explains why water isnt dragged out to the edges. And why youre not "pulled" straight down with "gravity", but also sideways, making it feel that earth is tilting. 

I like the earth being concave (CE! hehe). But it means that light has to be even more bent than on FE.

Im not trying to prove anything, just want to excerice those lazy grays.

It is my view that the Earth's gravitation cancels out the centripetal force.

Can you please explain how?  I'm trying to picture this in my mind's eye...the gravitation effect is pulling us essentially straight down towards the earth, but wouldn't the centripetal force of the rotating earth be at 90 degrees to the gravitational force?  I'm not sure I understand how this could cancel out...in order or that to work out, wouldn't the forces need to be 180 out of phase like noise cancelling headphone use counternoise sinewaves to cancel out noice sine waves?

This is the first time I've noticed any FE indication that the earth is rotating...usually the models presented have the spotlight-sun moving in some sort of ellipse above the surface of the earth...any rotation brings into play a force that works at a right angle to the gravitational effect we feel (or the continuous acceleration that our minds perceive as gravitation).  I'm genuinely curious about any information and/or explanation that you may put forth.

So getting back on track, Robosteve, can you please send some attention my way and answer the question I asked on p3?
Title: Re: Gravitational field of earth
Post by: Parsifal on August 28, 2008, 08:39:34 PM
To use a Newtonian simplification, he gravitational attraction is pulling us towards the Earth's centre of mass, which is beneath the north pole. At any location not at the pole, therefore, we feel a horizontal component of that attraction in the direction of the pole.
Title: Re: Gravitational field of earth
Post by: clydedaferret on August 28, 2008, 09:22:36 PM
For the love of God, can any of you flat earth people give me absolute proof that I myself do not produce a gravitational field?
Title: Re: Gravitational field of earth
Post by: Parsifal on August 28, 2008, 09:55:56 PM
For the love of God, can any of you flat earth people give me absolute proof that I myself do not produce a gravitational field?

But you do.
Title: Re: Gravitational field of earth
Post by: clydedaferret on August 28, 2008, 10:06:11 PM
What?
Title: Re: Gravitational field of earth
Post by: Parsifal on August 28, 2008, 10:23:38 PM
What?

You do produce a gravitational field, insofar as a gravitational field may be defined as curvature of spacetime.
Title: Re: Gravitational field of earth
Post by: clydedaferret on August 28, 2008, 10:57:38 PM
What?

You do produce a gravitational field, insofar as a gravitational field may be defined as curvature of spacetime.

Alright. Then for what reason does the earth not produce one?
Title: Re: Gravitational field of earth
Post by: sokarul on August 28, 2008, 11:03:14 PM
What?

You do produce a gravitational field, insofar as a gravitational field may be defined as curvature of spacetime.

Alright. Then for what reason does the earth not produce one?

The FET changes all the time and not all fe'ers agree on a single FET.  Robosteve believes that the FE has gravitation.   
Title: Re: Gravitational field of earth
Post by: clydedaferret on August 28, 2008, 11:04:11 PM
What?

You do produce a gravitational field, insofar as a gravitational field may be defined as curvature of spacetime.

Alright. Then for what reason does the earth not produce one?
The FET changes all the time and not all fe'ers agree on a single FET.  Robosteve believes that the FE has gravitation.   


Apparently, the flat earthers also believe in magic.
Title: Re: Gravitational field of earth
Post by: sokarul on August 28, 2008, 11:05:22 PM
What?

You do produce a gravitational field, insofar as a gravitational field may be defined as curvature of spacetime.

Alright. Then for what reason does the earth not produce one?
The FET changes all the time and not all fe'ers agree on a single FET.  Robosteve believes that the FE has gravitation.   


Apparently, the flat earthers also believe in magic.

I have said that so many times I have lost count. 
Title: Re: Gravitational field of earth
Post by: TheEngineer on August 28, 2008, 11:11:30 PM
Apparently, the RE'ers also believe in magic.
Fix'd
Title: Re: Gravitational field of earth
Post by: sokarul on August 28, 2008, 11:13:21 PM
Apparently, the RE'ers also believe in magic.
Fix'd

Way to troll the thread. 
Title: Re: Gravitational field of earth
Post by: clydedaferret on August 28, 2008, 11:13:46 PM
TheEngineer, how doesn't GPS require satellites?
Title: Re: Gravitational field of earth
Post by: cmdshft on August 29, 2008, 03:19:38 PM
You can use strato/psuedollites.

TheEngineer has a good thread about it here: http://theflatearthsociety.org/forum/index.php?topic=11864.0
Title: Re: Gravitational field of earth
Post by: mayhem on August 30, 2008, 08:05:47 AM
To use a Newtonian simplification, he gravitational attraction is pulling us towards the Earth's centre of mass, which is beneath the north pole. At any location not at the pole, therefore, we feel a horizontal component of that attraction in the direction of the pole.

I order for gravitation to cancel out centripetal force due to rotation, the center of gravity would have to be basically at the surface of the north pole.

If I understand the concept correctly, you really cannot use the center of mass in a non-spheroid earth as the center of gravitation.  If the earth is cylindrical and has gravitation then you will be pulled towards all of its mass at all times because each particle of mass also has gravitation.  In this scenario, if you were standing on the exact center of the top of the cylinder you would be pulled perpendicular to the level surface of the earth (or straight down).  But if you were at the equator you would be pulled slightly more towards the north pole that the south since there is more mass in the direction than towards the south.

But in any case, you would still be pulled "downwards", that is to say towards the bulk of the mass.  Being pulled downwards at all times on any surface of the earth only works in a speroid-shaped earth if you accept that all mass has gravitation and that the earth has mass. 

Basically I still don't see any way that gearth's graviation could possible cancel out centripetal force due to rotation...the forces simply cannot be at 180 degrees to each other.
Title: Re: Gravitational field of earth
Post by: Parsifal on August 30, 2008, 08:17:02 AM
I order for gravitation to cancel out centripetal force due to rotation, the center of gravity would have to be basically at the surface of the north pole.

If I understand the concept correctly, you really cannot use the center of mass in a non-spheroid earth as the center of gravitation.  If the earth is cylindrical and has gravitation then you will be pulled towards all of its mass at all times because each particle of mass also has gravitation.  In this scenario, if you were standing on the exact center of the top of the cylinder you would be pulled perpendicular to the level surface of the earth (or straight down).  But if you were at the equator you would be pulled slightly more towards the north pole that the south since there is more mass in the direction than towards the south.

But in any case, you would still be pulled "downwards", that is to say towards the bulk of the mass.  Being pulled downwards at all times on any surface of the earth only works in a speroid-shaped earth if you accept that all mass has gravitation and that the earth has mass. 

Basically I still don't see any way that gearth's graviation could possible cancel out centripetal force due to rotation...the forces simply cannot be at 180 degrees to each other.

There is a reason I used the words "horizontal component".
Title: Re: Gravitational field of earth
Post by: lolz at trollz on August 30, 2008, 08:43:57 AM
To use a Newtonian simplification, he gravitational attraction is pulling us towards the Earth's centre of mass, which is beneath the north pole. At any location not at the pole, therefore, we feel a horizontal component of that attraction in the direction of the pole.

But Newton was wrong, therefore anything you say in the whole thread is totally invalid and you loose forever!!!!!1!!11!!

Hey, I'm getting the hang of these FE arguments! 
Title: Re: Gravitational field of earth
Post by: Rig Navigator on August 30, 2008, 09:06:55 AM
You can use strato/psuedollites.

Not really.  The observed positions of these satellites can not be explained by a craft at the altitude that would have something in the atmosphere.  For our differential system, we receive signals showing the positions of the satellites relative to known reference points.  This allows us to correct the errors caused by atmospheric noise and other causes.  The differences in observed heights are not large enough to account for the difference in distance between our receivers and the reference station's receivers.
Title: Re: Gravitational field of earth
Post by: TheEngineer on August 30, 2008, 05:02:14 PM
TheEngineer, how doesn't GPS require satellites?
GPS requires only the known position of the transmitter, the current time on the transmitter and a receiver capable of decoding this info.  Throw in the known speed of light and there you go.
Title: Re: Gravitational field of earth
Post by: mayhem on August 30, 2008, 07:07:29 PM

There is a reason I used the words "horizontal component".

So it if your position that the earth does have a gravitational field, but it is not created by the mass of the entire earth, rather that there is single point source for gravitational attraction and that its located at the surface (or very near) at the north pole and that this gravitational pull is precisely cancelling out the centripetal force created by earth's rotation.

Is that correct?
Title: Re: Gravitational field of earth
Post by: Parsifal on August 30, 2008, 08:50:22 PM
So it if your position that the earth does have a gravitational field, but it is not created by the mass of the entire earth, rather that there is single point source for gravitational attraction and that its located at the surface (or very near) at the north pole and that this gravitational pull is precisely cancelling out the centripetal force created by earth's rotation.

Is that correct?

Uh, no.
Title: Re: Gravitational field of earth
Post by: lolz at trollz on August 30, 2008, 09:32:12 PM
osama's point seems to be that if you go up a mountain, there will be a pseudo force to the south.  He has once again failed at coherent theory. 
Title: Re: Gravitational field of earth
Post by: Ski on August 30, 2008, 11:06:39 PM
I believe the earth almost certainly has a gravitational field but it is likely indiscernible or nearly so.

Title: Re: Gravitational field of earth
Post by: Parsifal on August 30, 2008, 11:24:45 PM
osama's point seems to be that if you go up a mountain, there will be a pseudo force to the south.  He has once again failed at coherent theory. 

Where did I say that?
Title: Re: Gravitational field of earth
Post by: Rig Navigator on August 31, 2008, 06:10:02 AM
GPS requires only the known position of the transmitter, the current time on the transmitter and a receiver capable of decoding this info.  Throw in the known speed of light and there you go.

Your antenna shows you that the transmitter that you are receiving the signal from is directly overhead, it must be on a satellite.
Title: Re: Gravitational field of earth
Post by: divito the truthist on August 31, 2008, 07:16:59 AM
Your antenna shows you that the transmitter that you are receiving the signal from is directly overhead, it must be on a satellite.

Even if you accept that, then it must be directly overhead; not must be on a satellite.
Title: Re: Gravitational field of earth
Post by: Stabler12 on August 31, 2008, 07:23:35 AM
Your antenna shows you that the transmitter that you are receiving the signal from is directly overhead, it must be on a satellite.

Even if you accept that, then it must be directly overhead; not must be on a satellite.

If he's in the middle of the ocean, what tower or transmitting device is overhead?

Getting ready to try to get some sleep.  Have a good day/evening, y'all.
Title: Re: Gravitational field of earth
Post by: Ski on August 31, 2008, 09:43:29 AM
There are several forms of pseudolites that would enable the transmitter to be located above you.
Title: Re: Gravitational field of earth
Post by: mayhem on September 01, 2008, 07:13:57 PM
So it if your position that the earth does have a gravitational field, but it is not created by the mass of the entire earth, rather that there is single point source for gravitational attraction and that its located at the surface (or very near) at the north pole and that this gravitational pull is precisely cancelling out the centripetal force created by earth's rotation.

Is that correct?

Uh, no.

No.  Just no.  No to what part?  What part was incorrect?

Can you clarify then?  I've read and re-read the posts and it seems like you're saying that the gravitation emanates from a point source at or beneath the north pole. 
Title: Re: Gravitational field of earth
Post by: dyno on September 01, 2008, 08:16:50 PM
RS
With all the new physics you have to invent to explain the FE, do you still believe it is more elegant than a RE?

Anyway, how does the FE UA generate a opposing force at different latitudes which exactly cancels out the rotational acceleration? Is this another new type of physics?

You guys should be really interested in the LHC. You are the ones who should be searching for new particles.
Title: Re: Gravitational field of earth
Post by: Parsifal on September 02, 2008, 02:44:28 AM
No.  Just no.  No to what part?  What part was incorrect?

Can you clarify then?  I've read and re-read the posts and it seems like you're saying that the gravitation emanates from a point source at or beneath the north pole. 

Beneath the north pole, yes. In a rectangular co-ordinate system, it may be said to have a horizontal and a vertical component. Its horizontal component cancels out the fictitious centrifugal force, while its vertical component adds to the fictitious inertial force due to the acceleration of the Earth.

Anyway, how does the FE UA generate a opposing force at different latitudes which exactly cancels out the rotational acceleration? Is this another new type of physics?

The UA does not do this. It is the gravitation caused by the mass of the Earth that does.
Title: Re: Gravitational field of earth
Post by: Rig Navigator on September 02, 2008, 04:23:04 AM
The UA does not do this. It is the gravitation caused by the mass of the Earth that does.

I seem to remember a stickied thread where someone said that masses don't have gravitation or something to that effect.
Title: Re: Gravitational field of earth
Post by: Dr Matrix on September 02, 2008, 05:05:37 AM
I seem to remember a stickied thread where someone said that masses don't have gravitation or something to that effect.

There is no unified FE position on this - some feel the Earth is special and does not gravitate while other bodies do, some feel all matter gravitates and this has to be counteracted in some manner...
Title: Re: Gravitational field of earth
Post by: mayhem on September 02, 2008, 07:08:10 AM
No.  Just no.  No to what part?  What part was incorrect?

Can you clarify then?  I've read and re-read the posts and it seems like you're saying that the gravitation emanates from a point source at or beneath the north pole. 

Beneath the north pole, yes. In a rectangular co-ordinate system, it may be said to have a horizontal and a vertical component. Its horizontal component cancels out the fictitious centrifugal force, while its vertical component adds to the fictitious inertial force due to the acceleration of the Earth.

Ok then, fair enough.

How do you account for the horizontal component of the gravitational field counteracting the contripetal force at all lattitudes though?  Seems to me that the "rimward" horizontal force on an object at the ice wall would be substantially higher than at the equator.  As I understand it, the force of gravitation falls off more or less with the law of inverse squares, so as your distance from the source of gravitation increases, the effect of that gravitation falls off rather sharply.

Can you please explain your usage of the phrase "fictitious inertial force due to the acceleration of the Earth"?  Specifically what about the inertial force due to the acceleration of the Earth is fictitous?  I thought that the intertial force due to the acceleration of the Earth was a cornerstone of the FET explanation, or is it that calling it an "inertial force due to acceleration" while allowing most of us to accurately picture the concept in our mind's eye, is not technically correct? 

Just want to clarify this before some RET dudes start advertising that you're a turncoat on the FET and "another win for RET!" ensues.
Title: Re: Gravitational field of earth
Post by: Parsifal on September 02, 2008, 07:36:46 AM
Ok then, fair enough.

How do you account for the horizontal component of the gravitational field counteracting the contripetal force at all lattitudes though?  Seems to me that the "rimward" horizontal force on an object at the ice wall would be substantially higher than at the equator.  As I understand it, the force of gravitation falls off more or less with the law of inverse squares, so as your distance from the source of gravitation increases, the effect of that gravitation falls off rather sharply.

Can you please explain your usage of the phrase "fictitious inertial force due to the acceleration of the Earth"?  Specifically what about the inertial force due to the acceleration of the Earth is fictitous?  I thought that the intertial force due to the acceleration of the Earth was a cornerstone of the FET explanation, or is it that calling it an "inertial force due to acceleration" while allowing most of us to accurately picture the concept in our mind's eye, is not technically correct? 

Just want to clarify this before some RET dudes start advertising that you're a turncoat on the FET and "another win for RET!" ensues.

A fictitious force is an apparent force that is not really a force, caused by an acceleration in the opposite direction. An example is when you accelerate in a car, you feel pulled towards the back, even though it's really just the car accelerating forwards. I have indicated fictitious forces rather than their corresponding accelerations because I believe it easier to interpret the diagram that way.

Also, you would be correct if the centre of mass was at the north pole. Being significantly below it, however, the difference in the distance from the centre of mass is negligible, and the horizontal component of the force increases with the sine of the angle subtended by the distance between you and the north pole at the Earth's centre of mass. For distances away from the north pole that are very small as compared with the distance to the Earth's centre of mass (which is everywhere on Earth, if the centre of mass is far enough underground), this corresponds to an almost perfect linear relationship between the horizontal component of the fictitious gravitational force and the distance away from the north pole.
Title: Re: Gravitational field of earth
Post by: mayhem on September 02, 2008, 09:00:08 AM
If thats the case, then why can we measure a basically steady gravitation of 9.8ms^2 at all lattitudes?  If the point of gravitation is deep enough beneath the north pole that its horizontal effect is equal and opposite to the increasing centripetal force felt at more southerly lattitudes then its vertical component at those southerly lattitudes must be relatively negligible, yes?  This would seen to indicate that the "force of gravity" for my lack of a better term (but I'm pretty sure you know what I mean by it) would vary significantly at different lattitudes...at the extreme south it would be almost totally due to the acceleration of the earth and at the norht pole it would be coupled with the steady acceleration of the earth so the acceleration of gravity (again, lacking a better term) as measured at sea level across all lattitudes should be seen as increasing significantly the further you go north. 

I'm sorry if I am misunderstanding you and I'm pestering you with inane questions, I'm just trying to get a complete picture of your concept and appreciate your time spent explaining it without any effort expended on trying to belittle my questions or name calling.

My mind is basically reducing all this down to geomerty and I'm using right triangles to represent the north pole, distance to the different lattitudes and the hypotenuse is the distance from any point on earth to the source of earth's gravitation...please let me know if that picture is incorrect and if can, please provide me with a more accurate analogy.

Do you have approximate distances and the relative strength of the gravitational field from that source worked out?  It seems like it must be buried at least as deep beneath the north pole as the radius of the cylinder (or maybe significantly deeper...an order of magnitude?) in order for the change in lattutude to be an insignificant distance to show a gravitational field effect delta.  I think I saw you posit last night that the earth may be on the order of terameters thick, does your model assume a more or less consistent density such that the CG is really within a short margin of error at the true "center of the earth"?
Title: Re: Gravitational field of earth
Post by: Parsifal on September 02, 2008, 09:04:47 AM
If thats the case, then why can we measure a basically steady gravitation of 9.8ms^2 at all lattitudes?  If the point of gravitation is deep enough beneath the north pole that its horizontal effect is equal and opposite to the increasing centripetal force felt at more southerly lattitudes then its vertical component at those southerly lattitudes must be relatively negligible, yes?  This would seen to indicate that the "force of gravity" for my lack of a better term (but I'm pretty sure you know what I mean by it) would vary significantly at different lattitudes...at the extreme south it would be almost totally due to the acceleration of the earth and at the norht pole it would be coupled with the steady acceleration of the earth so the acceleration of gravity (again, lacking a better term) as measured at sea level across all lattitudes should be seen as increasing significantly the further you go north.

I'm sorry if I am misunderstanding you and I'm pestering you with inane questions, I'm just trying to get a complete picture of your concept and appreciate your time spent explaining it without any effort expended on trying to belittle my questions or name calling.

My mind is basically reducing all this down to geomerty and I'm using right triangles to represent the north pole, distance to the different lattitudes and the hypotenuse is the distance from any point on earth to the source of earth's gravitation...please let me know if that picture is incorrect and if can, please provide me with a more accurate analogy.

That picture is correct, yes. The shortest side, by many orders of magnitude, of that triangle is the one between the north pole and the observer. Thus, moving around on the Earth has a negligible effect on the vertical component of the gravitational attraction of the Earth.

Do you have approximate distances and the relative strength of the gravitational field from that source worked out?  It seems like it must be buried at least as deep beneath the north pole as the radius of the cylinder (or maybe significantly deeper...an order of magnitude?) in order for the change in lattutude to be an insignificant distance to show a gravitational field effect delta.  I think I saw you posit last night that the earth may be on the order of terameters thick, does your model assume a more or less consistent density such that the CG is really within a short margin of error at the true "center of the earth"?

Yes. When performing my calculations, I used an idealised model in which the Earth is a perfect cylinder of uniform density.
Title: Re: Gravitational field of earth
Post by: mayhem on September 02, 2008, 09:29:20 AM
That picture is correct, yes. The shortest side, by many orders of magnitude, of that triangle is the one between the north pole and the observer. Thus, moving around on the Earth has a negligible effect on the vertical component of the gravitational attraction of the Earth.

Thank you for the clarification.

I'm still not sure I understand how this model accounts for essentailly the same measurable force of gravitation felt throughout the world.  It still seems like it should be measurably different at more and more southern lattitudes.  I think I understand that you're saying the point source of gravity is very, very deep...hundreds of thousands of km?  But still, with properly calibrated instrumentation it should be possible to accurately measure this and show a difference across lattitudes.
Title: Re: Gravitational field of earth
Post by: Parsifal on September 02, 2008, 02:19:48 PM
I'm still not sure I understand how this model accounts for essentailly the same measurable force of gravitation felt throughout the world.  It still seems like it should be measurably different at more and more southern lattitudes.  I think I understand that you're saying the point source of gravity is very, very deep...hundreds of thousands of km?  But still, with properly calibrated instrumentation it should be possible to accurately measure this and show a difference across lattitudes.

Deeper than that. Most likely, a few billion kilometres.
Title: Re: Gravitational field of earth
Post by: dyno on September 02, 2008, 08:06:53 PM
I seem to remember a stickied thread where someone said that masses don't have gravitation or something to that effect.

There is no unified FE position on this - some feel the Earth is special and does not gravitate while other bodies do, some feel all matter gravitates and this has to be counteracted in some manner...

Problem is they pick and choose their position depending on the argument.
Title: Re: Gravitational field of earth
Post by: Roundy the Truthinessist on September 02, 2008, 09:40:10 PM
I seem to remember a stickied thread where someone said that masses don't have gravitation or something to that effect.

There is no unified FE position on this - some feel the Earth is special and does not gravitate while other bodies do, some feel all matter gravitates and this has to be counteracted in some manner...

Problem is they pick and choose their position depending on the argument.

Not me.  I stick by one model.
Title: Re: Gravitational field of earth
Post by: dyno on September 02, 2008, 10:36:39 PM
Which is?

Infinite plane or finite plane?
Infinite thickness or finite thickness?
1 source of acceleration or multiple?
Bendy light or normal?
Celestial gears or conventional universe?
Self lit moon or reflective moon?
Heat from the Sun or from the Earth?

etc etc....
Title: Re: Gravitational field of earth
Post by: Roundy the Truthinessist on September 02, 2008, 10:42:23 PM
Which is?

Infinite plane or finite plane?
Infinite thickness or finite thickness?
1 source of acceleration or multiple?
Bendy light or normal?
Celestial gears or conventional universe?
Self lit moon or reflective moon?
Heat from the Sun or from the Earth?

etc etc....

probably finite
probably finite
one source of acceleration, multiple sources of gravitation
not sure yet
celestial gears
reflective moon
heat from sun

Go ahead, prove me wrong.
Title: Re: Gravitational field of earth
Post by: dyno on September 02, 2008, 10:53:05 PM
Was trying to determine if you have a concrete position.

What are the multiple sources of gravitation? Do they affect all things equally?

What do you think of supernova, planetary nebulae, galaxies and other high energy celestial events.
Just the things that can be seen with a moderately powerful telescope by anyone.
Title: Re: Gravitational field of earth
Post by: Roundy the Truthinessist on September 02, 2008, 10:58:45 PM
Was trying to determine if you have a concrete position.

What are the multiple sources of gravitation? Do they affect all things equally?

What do you think of supernova, planetary nebulae, galaxies and other high energy celestial events.
Just the things that can be seen with a moderately powerful telescope by anyone.

I believe the earth's upward acceleration by the UA is one type of gravitation.  The other affects the heavens alone, I believe because they are composed of something very different from matter as it exists on earth.  It may be electromagnetic in nature.

I believe in everything you bring up, just on a much smaller scale.  These events may well be very powerful, they're just a lot tinier.
Title: Re: Gravitational field of earth
Post by: dyno on September 02, 2008, 11:09:44 PM
So why don't the Sun and Moon affect anything other than the planets?

I'm not sure where you stand on this. Do the stars affect things on Earth? The Sun and Moon do right? Why don't the Sun and Moon interact with celestial objects, other than the planets and comets etc. If the stars and Sun affect things on Earth from 3000+miles away they should affect each other from distances much less than that.

What are the stars composed of?
What causes instabilities in such minute bodies?
Title: Re: Gravitational field of earth
Post by: Roundy the Truthinessist on September 02, 2008, 11:15:49 PM
They do.  Everything up there affects everything else.

I'm not sure.  The sun and moon do definitely exert some kind of influence on earth, but I believe that's because they're so close.  All of the heavenly bodies are highly energetic, however small they are.  They may be very massive, but I think they're actually much lighter than the earth and that's why they kind of float above us.

The stars are bundles of energy.
It might just be their natural way of interacting with each other.