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Flat Earth Discussion Boards => Flat Earth Debate => Topic started by: parsec on December 28, 2009, 01:23:00 AM

Title: Proofs of varying gravity
Post by: parsec on December 28, 2009, 01:23:00 AM
Here we post conclusive evidence that gravity varies  with height. Let me start:

Sorry, gravity isn't always 'down' it can be in any direction, the deplection of plum bobs near mountains clearly shows this.
Title: Re: Proofs of varying gravity
Post by: Tom Bishop on December 28, 2009, 01:26:40 AM
After the advent of Newton's Theory of Gravity where was a widespread attempt to prove it by meticulously studying plum bobs near mountains. It failed. No one was able to observe deviation of any sort, despite his equations predicting that variation should be readily observable with basic instruments.

Newton himself said that the failure was one of the most devastating blows to his theory.
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 01:35:48 AM
But, these scientists (http://www.physicsforums.com/archive/index.php/t-138568.html) have even calculated the deflection angle.
Title: Re: Proofs of varying gravity
Post by: Tom Bishop on December 28, 2009, 01:38:53 AM
The matter has been over and done with.

Newton's equations predicted a deflection near the earth's greatest mountains, and there was none, leaving the Newtonians to mumble about unseen dense underground rocks on the other side of the plum bobs to balance things out in each and every case.
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 01:41:11 AM
How about when I try to boil my eggs on a high mountain-top? They're always too soft boiled.
Title: Re: Proofs of varying gravity
Post by: Tom Bishop on December 28, 2009, 02:13:03 AM
How about when I try to boil my eggs on a high mountain-top? They're always too soft boiled.

I personally say that the stars have a slight attracting field.

However, other FE proponents vehemently deny any alteration of g at higher altitudes.
Title: Re: Proofs of varying gravity
Post by: Sutekh on December 28, 2009, 04:17:39 AM
How about when I try to boil my eggs on a high mountain-top? They're always too soft boiled.

I personally say that the stars have a slight attracting field.

However, other FE proponents vehemently deny any alteration of g at higher altitudes.

yeah but who cares? I can vehemently deny the sky is blue. g varies. its differnet at the equator compared to the poles.
Title: Re: Proofs of varying gravity
Post by: Thermal Detonator on December 28, 2009, 05:45:38 AM
Of course Bishop will deny it. It's his standard procedure when confronted with evidence that blows FET away. He has no other course of action.
Title: Re: Proofs of varying gravity
Post by: ugaboga313 on December 28, 2009, 07:19:23 AM
Wasn't there an experiment not using plum-bobs that detects the subtle change in gravity between two objects? How do you respond to that? 
Title: Re: Proofs of varying gravity
Post by: onetwothreefour on December 28, 2009, 08:42:20 AM
Wasn't there an experiment not using plum-bobs that detects the subtle change in gravity between two objects? How do you respond to that? 

I would respond by saying that you might want to cite the specific experiment rather than just mentioning it.
Title: Re: Proofs of varying gravity
Post by: ugaboga313 on December 28, 2009, 09:08:40 AM
I would respond with the experiment. I forgot its name. http://en.wikipedia.org/wiki/Torsion_balance#Torsion_balance
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 10:41:22 AM
I would respond with the experiment. I forgot its name. http://en.wikipedia.org/wiki/Torsion_balance#Torsion_balance
I think you mean this:
http://en.wikipedia.org/wiki/Cavendish_experiment (http://en.wikipedia.org/wiki/Cavendish_experiment).
Title: Re: Proofs of varying gravity
Post by: onetwothreefour on December 28, 2009, 10:58:25 AM
I would respond with the experiment. I forgot its name. http://en.wikipedia.org/wiki/Torsion_balance#Torsion_balance
I think you mean this:
http://en.wikipedia.org/wiki/Cavendish_experiment (http://en.wikipedia.org/wiki/Cavendish_experiment).

What is your take on it Parsec?
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 11:00:05 AM
It's not a direct proof of varying gravity, is it?
Title: Re: Proofs of varying gravity
Post by: onetwothreefour on December 28, 2009, 11:04:50 AM
It's not a direct proof of varying gravity, is it?
You don't think it's at least a bit compelling?
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 28, 2009, 11:09:58 AM
How about when I try to boil my eggs on a high mountain-top? They're always too soft boiled.
Uh, Parsec? That's definitely due to varying atmospheric pressure with altitude, and not gravity. The difference in gravity between the surface of the Earth at sea level (6,378 km) and the surface of the Earth at high elevation (6,382 km for the highest city on Earth, maybe 6,386 km if you're cooking on the summit of everest), as predicted by the RE model, is at most 1-(6,378/6,386)2=.25%. I have a hard time believing you'd notice that when cooking eggs. The variations due to pressure are much more dramatic (and are also easily explained in the FE model).
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 11:14:10 AM
How about when I try to boil my eggs on a high mountain-top? They're always too soft boiled.
Uh, Parsec? That's definitely due to varying atmospheric pressure with altitude, and not gravity. The difference in gravity between the surface of the Earth at sea level (6,378 km) and the surface of the Earth at high elevation (6,382 km for the highest city on Earth, maybe 6,386 km if you're cooking on the summit of everest), as predicted by the RE model, is at most 1-(6,378/6,386)2=.25%. I have a hard time believing you'd notice that when cooking eggs. The variations due to pressure are much more dramatic (and are also easily explained in the FE model).
but, atmospheric pressure is due to the weight of the air. The higher the g, the higher the pressure and vice versa.
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 28, 2009, 11:22:11 AM
but, atmospheric pressure is due to the weight of the air. The higher the g, the higher the pressure and vice versa.
That's true, but not a significant influence on pressure. Pressure is due to the weight of a column of air above you (to first approximation, neglecting effects such as the weather). This weight is less at elevation than at sea level not because of the minute decrease in g but rather because the column of air above a point at sea level contains a lot more air than the column of air above a point at high elevation.

Again, this is explained just as easily by the UA model of the FE (or other FE models of gravity) as by the round Earth model, so it hardly constitutes proof of a round Earth.
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 11:26:50 AM
So, according to your theory, at the top of the atmosphere, there should be zero pressure, since, by definition of the top, there should be no column of air above it. How is this possible?
Title: Re: Proofs of varying gravity
Post by: ugaboga313 on December 28, 2009, 11:29:44 AM
That is true, space is basically a vacuum. Very good Parsec.
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 11:30:42 AM
so, space is COMPLETELY empty?!
Title: Re: Proofs of varying gravity
Post by: markjo on December 28, 2009, 11:33:01 AM
so, space is COMPLETELY empty?!

Space is a near, but not perfect, vacuum. 
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 28, 2009, 11:37:03 AM
So, according to your theory, at the top of the atmosphere, there should be zero pressure, since, by definition of the top, there should be no column of air above it. How is this possible?
Well, the atmosphere gradually thins out to vacuum (which still isn't true vacuum (http://en.wikipedia.org/wiki/Vacuum#Outer_space)), so there's not really a distinct "top" of the atmosphere (although the Kármán line is sometimes used for definitional purposes). But otherwise that's true: there is no pressure in a vacuum. I'm not quite sure why you ask "How is this possible?" however, since it seems perfectly plausible to me, so I'll counter: why wouldn't it be possible?
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 11:37:09 AM
So, let me get this straight. Space has some small, but nonzero density and zero pressure. Let's say ideal gas law holds:

P = ρ*k*T/m,

where:
ρ is the average mass density,
m is the average mass of the molecules,
k = 1.3807x10-23 J/K is Boltzmann constant and
T is the absolute temperature.

So, according to what you said before, T = 0 K! But, this is impossible according to the Laws of Thermodynamics?!
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 28, 2009, 11:46:01 AM
So, according to what you said before, T = 0 K! But, this is impossible according to the Laws of Thermodynamics?!
I said nothing of the sort. I said that pressure is zero in a perfect vacuum, which is true, and in accordance with the ideal gas law (since n=0). In what is commonly referred to as the "vacuum" of space (which, as I said, is not a true vacuum), the density is very small but nonzero, and the pressure is similarly very small but nonzero.
Title: Re: Proofs of varying gravity
Post by: ugaboga313 on December 28, 2009, 11:48:59 AM
There is very few moles in space. So, it is about 2.6K degrees. I don't see the problem here.
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 11:49:27 AM
So, according to what you said before, T = 0 K! But, this is impossible according to the Laws of Thermodynamics?!
I said nothing of the sort. I said that pressure is zero in a perfect vacuum, which is true, and in accordance with the ideal gas law (since n=0). In what is commonly referred to as the "vacuum" of space (which, as I said, is not a true vacuum), the density is very small but nonzero, and the pressure is similarly very small but nonzero.
This post was not directed as a reply to your post, but, instead, to one above you, since I was typing it at the same time as you.

As a reply to your post, if the atmosphere has no top, then it will have an infinite mass and the pressure at sea level would also be infinite.
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 28, 2009, 11:52:42 AM
This post was not directed as a reply to your post, but, instead, to one above you, since I was typing it at the same time as you.
Oh, excuse me.

Quote
As a reply to your post, if the atmosphere has no top, then it will have an infinite mass and the pressure at sea level would also be infinite.
No, because, while there is no top, it gradually thins out to vacuum, so it still has only finite mass, and results in finite pressure.
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 28, 2009, 12:03:45 PM
Ok, Parsec, let's get this straight: are you actually saying that the difference in cooking properties of eggs and other foods between sea level and high elevation constitutes evidence that the Earth is round?
Title: Re: Proofs of varying gravity
Post by: Thermal Detonator on December 28, 2009, 12:37:48 PM
So, let me get this straight. Space has some small, but nonzero density and zero pressure. Let's say ideal gas law holds:

P = ?*k*T/m,

where:
? is the average mass density,
m is the average mass of the molecules,
k = 1.3807x10-23 J/K is Boltzmann constant and
T is the absolute temperature.

So, according to what you said before, T = 0 K! But, this is impossible according to the Laws of Thermodynamics?!


If you had a perfect vacuum, temperature becomes irrelevant as it's a measure of the energy of the molecules in an area. If you have no molecules in an area (which is the definition of a vacuum) then it cannot be said to have a temperature, and thermodynamics is not violated.
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 01:00:46 PM
Quote
As a reply to your post, if the atmosphere has no top, then it will have an infinite mass and the pressure at sea level would also be infinite.
No, because, while there is no top, it gradually thins out to vacuum, so it still has only finite mass, and results in finite pressure.

Ok, I guess you must be discussing with the RE model in your mind. If the atmosphere has such a huge extent, then, surely, we must take into account the varying gravity at these high altitudes. Let me quantify what you said about the finite mass and pressure.

Let ρ(r) be the dependence of the density on the distance from the center of the RE. We assume spherical symmetry to simplify the problem. The mass of the atmosphere that is within a spherical shell between spheres with radii r and r + dr, with a volume dV = 4*π*r2*dr is:

dm/dr = 4*π*ρ*r2.
(1)
In order that the total mass be finite, the integral:
m = 4*π*Integral[t2*ρ(t), {t, R, Infinity}]
(2)
must converge for r -> Infinity.
Now, let us look at the pressure P = P(r). In equilibrium, the forces acting on each small volume element cancel out. The volume density of the pressure force is given by -grad P, or since P depends only on r, this vector is simply -(dP/dr) r0, where r0 is a unit vector in radial direction. The other force acting on this element is the gravitational force. Its volume density is ρ*g, where g is the gravitational acceleration of the Earth at a given point. This, according to the inverse square law is:

g(r) = -g0*R2/r2 r0,
(3)
where
g0 is the gravitational acceleration on the surface of the Earth and
R is the radius of the (Round) Earth.

Finally, we get the following equation for the rate of change of pressure:

dP/dr = -g0*R2*ρ(r)/r2,
(4)
Equation (4) are still not ''closed'', since there are more unknowns (P(r) and ρ(r)) than equations. We would need a detailed equation of state. The ideal gas law:

P = ρ*k*T/m,
(5)
is not sufficient on its own because we either need to specify how the temperature changes with altitude, or supply another physical law relating the balance of transfer of heat. This is a complicated task in the least.

As a rough approximation, let us suppose that T = const. (isothermal atmosphere). Then, by eliminating pressure from (5) into (4), we get the following equation:
/dr = -(m*g0*R2/k*T)*ρ/r2.
(6)
We couple this equation with the initial condition ρ(R) = ρ0, the density of the atmosphere on the surface of the Earth. The variables can be separated in this equation and the integrals are:
Integral[1/ρ',{ρ', ρ0, ρ(r)}] = Ln(ρ(r)/ρ0),

Integral[1/t2,{t, R, r}] = -(1/r - 1/R),

ρ(r) = ρ0*Exp[(m*g0*R2)/(k*T)*(1/r - 1/R)].
(7)
The important feature of Eqn.(7) is that, as r->Infinity, ρ tends to a nonzero limit:

ρ(Infinity) = ρ0*Exp[-m*g*R/(k*T)].
(8)
But, then, the necessary condition for the convergence of integral (2) is not fullfilled and the mass of the atmosphere is infinite!

Note that the usual barometric formula quoted in most textbooks is obtained by assuming a flat earth with constant g and then we get a finite mass for the atmosphere.
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 01:09:48 PM
So, let me get this straight. Space has some small, but nonzero density and zero pressure. Let's say ideal gas law holds:

P = ?*k*T/m,

where:
? is the average mass density,
m is the average mass of the molecules,
k = 1.3807x10-23 J/K is Boltzmann constant and
T is the absolute temperature.

So, according to what you said before, T = 0 K! But, this is impossible according to the Laws of Thermodynamics?!


If you had a perfect vacuum, temperature becomes irrelevant as it's a measure of the energy of the molecules in an area. If you have no molecules in an area (which is the definition of a vacuum) then it cannot be said to have a temperature, and thermodynamics is not violated.
You can still have photons even if no substance is present and those can be assigned a temperature.
Title: Re: Proofs of varying gravity
Post by: ugaboga313 on December 28, 2009, 01:18:31 PM
I don't get what your math is proving. If there is infinite mass then yes infinite pressure. But the universe is not infinite and nor is our atmosphere.
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 01:19:33 PM
I don't get your math.
Thanks for playing. Try again.
Title: Re: Proofs of varying gravity
Post by: ugaboga313 on December 28, 2009, 01:24:36 PM
Nah your just using fancy calculus (Which I know) to prove a very basic scenario. You are trying to dazzle. You are using integrals to find out how the infinite series can have a finite limit. Basically how infinite atmosphere at a decreasing density can have a finite pressure. You assume that the universe is infinite and the atmosphere is infinite. Pressure basically becomes negligible 60 or so miles above the earth. Sure there is some matter but its pressure is basically nil and gravity from all the other planets cancels out this pressure.

This is basic science that even FE has to contend with.
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 01:27:13 PM
Nah your just using fancy calculus (Which I know) to prove a very basic scenario. You are trying to dazzle. You are using integrals to find out how the infinite series can have a finite limit. Basically how infinite atmosphere at a decreasing density can have a finite pressure. You assume that the universe is infinite and the atmosphere is infinite. Pressure basically becomes negligible 60 or so miles above the earth. Sure there is some matter but its pressure is basically nil and gravity from all the other planets cancels out this pressure.

This is basic science that even FE has to contend with.
So, you are saying that this is not infinite because the Universe has a finite size and our atmosphere expands throughout all the Universe. Gotcha  ;)
Title: Re: Proofs of varying gravity
Post by: ugaboga313 on December 28, 2009, 01:30:29 PM
Same with FE. Please don't be sarcastic and just make your point. Just cause you can use integrals to find volumes and evaluate infinite series doesn't mean a good dose of common sense can substitute.


But tell me how FE deals with this. We aren't dead by pressure which means either our atmosphere is limited or the universe is limited. We know that perfect vacuums are impossible so its the latter. Which is the same in both.


Doesn't the cavendish experiment prove varying gravity (What the thread is on, not atmosphere).
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 01:37:03 PM
Please find a mistake in my derivation. If not, stop with the low-content posting.
Title: Re: Proofs of varying gravity
Post by: ugaboga313 on December 28, 2009, 01:41:47 PM
So only fancy smancy people with knowledge of integral calculus are allowed to post? I don't even understand why we are talking about the atmosphere. The topic is about varying gravity and I have given proof of that. You defer with boiling eggs which are affected by pressure far more than gravity.


Your derivation seems fine but you assume that no other planets have gravity pulling the atmosphere away. Also you assume that at all concentrations there is a pressure. One atom will only exert pressure when it bumps into something. At space levels of density, they only bump very infrequently. Thus the pressure outside of our atmosphere (60 or so miles) is negligible.


Also show how cavendish's experiment was wrong.

EDIT: Who are you arguing for? Or are you just arguing?
Title: Re: Proofs of varying gravity
Post by: Thermal Detonator on December 28, 2009, 02:29:59 PM

You can still have photons even if no substance is present and those can be assigned a temperature.

True, but until they interact with other matter they really only have a "potential" temperature, as they are still holding on to their energy. Photons don't really apply in the regular laws of thermodynamics unless they are heating up matter.
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 02:31:53 PM

You can still have photons even if no substance is present and those can be assigned a temperature.

True, but until they interact with other matter they really only have a "potential" temperature, as they are still holding on to their energy. Photons don't really apply in the regular laws of thermodynamics unless they are heating up matter.
What regular laws of thermodynamics do photons violate?
Title: Re: Proofs of varying gravity
Post by: Thermal Detonator on December 28, 2009, 02:40:25 PM
They don't violate any, that's not what I meant... I meant in terms of the equation you had about temperature, pressure and number of molecules, if you bring photons in then it complicates the maths somewhat.
If you have a true vacuum, if photons are travelling through it but not interacting with anything, you could still class that as having no measurable temperature. The photons will leave the area of the vacuum without depositing any energy.
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 28, 2009, 02:48:21 PM
Quote
As a reply to your post, if the atmosphere has no top, then it will have an infinite mass and the pressure at sea level would also be infinite.
No, because, while there is no top, it gradually thins out to vacuum, so it still has only finite mass, and results in finite pressure.

Ok, I guess you must be discussing with the RE model in your mind.
No, either model is consistent with finite pressure at sea level and a reduction of air pressure according to height. I had the FE model in mind when I wrote that, since you seem to be arguing that the FE model is inconsistent with observed air pressure, which I argue is not the case, and that a consistent account of air pressure can be made in both models.

There is a qualitative difference, as you point out: in the RE model, it is consistent that density does not tend to zero as r tends to infinity, because the force of gravity decreases with distance, and so the weight of atmosphere above a point on the surface of the Earth will still be finite, even if the mass is infinite. In the FE model with universal acceleration (or gravity from a flat Earth with infinite extent) gravity is constant and doesn't decrease with distance, so the result is infinite pressure at sea level if density does not asymptotically approach zero as height increases. So you are right, the FE model is inconsistent if the density does not asymptotically approach 0.

However, your derivation of the limiting density ρinfinity is only valid for a round Earth, because you are assuming that gravity drops with distance, as it does in the RE model.
Quote
If the atmosphere has such a huge extent, then, surely, we must take into account the varying gravity at these high altitudes.
However, in the most common FE model (universal acceleration) gravity is constant, and does not vary with altitude. If you assumed constant gravity, you could carry out the same derivation, and would in fact find that ρinfinity is finite:

Let ρ(r) be the dependence of the density on the altitude above an accelerating FE. (We neglect effects of weather on pressure and therefore density. By symmetry, density should depend only on altitude.) Consider a volume element at height r. There are two forces acting on this bit of atmosphere: gravity and pressure. The force per unit volume from gravity is proportional to density ρ times g, and acts directly downward. The force density due to pressure is equal to the pressure gradient. Again by symmetry (and again neglecting weather effects) pressure should depend only on altitude; let P(r) be the pressure at height r. Then we get a new version of your equation (4),
dP/dr = -gρ(r),
which is really the same equation but with g being constant rather than depending on r. I will use your same simplifying assumption of an isothermal atmosphere, so that ρ(r)=kP(r), for some constant k. This gives us a simple differential equation for atmospheric density
/dr = -kgρ,
which has as its solution
ρ(r) = ρ0e-kgr,
with ρ0 being the atmospheric density at height 0. This indeed asymptotically approaches zero as r tends to infinity, and the total mass above each square meter of flat Earth (in this model) is
(http://upload.wikimedia.org/math/4/9/d/49dfcfc1209563770a6079c63e3867f1.png)
which is finite. In fact, if you work it out, the pressure at height h is exactly the total mass per unit area in a column of atmosphere above height h, times the gravitational acceleration g:
(http://upload.wikimedia.org/math/d/b/e/dbe7e3693682779f8af7c12e0009ad5b.png)

As I said before, you can make a completely consistent account of atmospheric pressure in both models, whether gravity depends on altitude or not. I'm at a loss as to how this thread, originally about gravity dependence on altitude, has become so bogged down by talking about pressure. I'll repeat my above question, which Parsec still hasn't answered (unless I missed it somewhere?)

Ok, Parsec, let's get this straight: are you actually saying that the difference in cooking properties of eggs and other foods between sea level and high elevation constitutes evidence that the Earth is round?

If not, let's move away from this whole pressure distraction, and get back to the matter of gravitational dependence on altitude. Can anyone propose a reasonable experiment that an average board member can replicate that demonstrates that it does, or do we have to rely on professional scientists (who, it will be argued, are in on the conspiracy).

Edit: damn, some of my symbols are still displaying as question marks, even though they looked fine in preview. If anyone can tell me why this is, I'd be grateful. All of the symbols in this post are supposed to be rhos. Oh for board support of latex...
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 02:54:49 PM
The ideal gas law holds true for non-relativistic, non-interacting particles. The photons, on the other hand, are ultrarelativistic, since they are moving with c. Nevertheless, a gas of photons exerts a pressure according to the formula:

P = u/3,

where u is the energy density of the photons. If the temperature of the 'photon gas' is T, then the energy density is given by:

u = A*T4,

where A is a combination of fundamental constants:

A =π4/(15*(ħ*c)3).

So the photon gas exerts zero pressure only at absolute zero.
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 28, 2009, 03:01:14 PM
So only fancy smancy people with knowledge of integral calculus are allowed to post? I don't even understand why we are talking about the atmosphere. The topic is about varying gravity and I have given proof of that. You defer with boiling eggs which are affected by pressure far more than gravity.
Parsec seems to have this annoying tendency to write equation-filled posts, and then assume that all replies that don't contain an equal number of equations are written by people who are incapable of understanding his equation-filled posts, even though it is often much more understandable to most people (and therefore preferable) to explain the same thing using more words and fewer equations. I'm reminded of this thread (http://www.theflatearthsociety.org/forum/index.php?topic=34798.0), where I gave a short and relatively equation-free explanation why one of his assumptions (that gravitational edge effects from a wide thin disk of uniform density are important in a region about as wide as the disk is thick) was false, figuring that he could fill in the details himself with a little reflection. His response was,
Either present something meaningful with complete derivations or stop pretending like you understand what is discussed.

Parsec, I think you would find that people are more receptive to your arguments when you are more receptive to theirs. I'm not telling you to accept false arguments without question, but explain why and where you disagree (if you disagree), rather than dismissing other's arguments out of hand. When someone posts an argument that is not filled with equations, don't ignore it just because it doesn't include greek letters, and don't assume that whoever posted it isn't just as comfortable with equations as you.
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 03:15:18 PM
I am sorry. I will try to explain my assertion without equations:

Quote
As a reply to your post, if the atmosphere has no top, then it will have an infinite mass and the pressure at sea level would also be infinite.
No, because, while there is no top, it gradually thins out to vacuum, so it still has only finite mass, and results in finite pressure.

This is not possible in the RE model with g varying with altitude according to the Inverse square law.
Title: Re: Proofs of varying gravity
Post by: markjo on December 28, 2009, 03:15:38 PM
Nevertheless, a gas of photons exerts a pressure according to the formula:

A "gas of photons"?  ???
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 03:16:37 PM
Nevertheless, a gas of photons exerts a pressure according to the formula:

A "gas of photons"?  ???
lol, yes. But stop derailing the thread.
Title: Re: Proofs of varying gravity
Post by: Tom Bishop on December 28, 2009, 03:20:09 PM
I would respond with the experiment. I forgot its name. http://en.wikipedia.org/wiki/Torsion_balance#Torsion_balance
I think you mean this:
http://en.wikipedia.org/wiki/Cavendish_experiment (http://en.wikipedia.org/wiki/Cavendish_experiment).

http://milesmathis.com/caven.html
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 28, 2009, 03:25:57 PM
I am sorry. I will try to explain my assertion without equations:

Quote
As a reply to your post, if the atmosphere has no top, then it will have an infinite mass and the pressure at sea level would also be infinite.
No, because, while there is no top, it gradually thins out to vacuum, so it still has only finite mass, and results in finite pressure.

This is not possible in the RE model with g varying with altitude according to the Inverse square law.
Yeah, thanks, I understood your previous post just fine. As I said in my above post, my comment was with regards to the FE model, where gravity doesn't vary with altitude, and the math comes out just fine. The statement that is true in both models is that the volume of gas above any point on the Earth has finite weight, and results in finite pressure.

You still haven't answered my question: are you saying that the difference in cooking properties of eggs and other foods between sea level and high elevation constitutes evidence that the Earth is round? If not, why did you even bring it up in this thread?
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 03:29:31 PM
So, let me get this straight: It is ok that the mass of the atmosphere is infinite as long as it causes finite pressure!

Also:
You still haven't answered my question: are you saying that the difference in cooking properties of eggs and other foods between sea level and high elevation constitutes evidence that the Earth is round? If not, why did you even bring it up in this thread?
Please provide proof where I have claimed that.
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 28, 2009, 03:39:14 PM
So, let me get this straight: It is ok that the mass of the atmosphere is infinite as long as it causes finite pressure!
Well, there is not really a definite end to the atmosphere, as it gradually fades into the interstellar vacuum, which still isn't a true vacuum, as already discussed. So if you are asking whether it is okay if there is an infinite amount of mass in the universe, my response is sure, why not? There is a finite amount of mass below the Kármán line, or other lines one might call the edge of the atmosphere, but those are just lines.

Quote
You still haven't answered my question: are you saying that the difference in cooking properties of eggs and other foods between sea level and high elevation constitutes evidence that the Earth is round? If not, why did you even bring it up in this thread?
Please provide proof where I have claimed that.
I didn't say you did, I just asked a question which you still have not answered. Just answer the question already, and I'll stop asking it.
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 03:52:06 PM
The varying of boiling temperature with altitude is a conclusive evidence for RE.
Title: Re: Proofs of varying gravity
Post by: markjo on December 28, 2009, 04:21:58 PM
I would respond with the experiment. I forgot its name. http://en.wikipedia.org/wiki/Torsion_balance#Torsion_balance
I think you mean this:
http://en.wikipedia.org/wiki/Cavendish_experiment (http://en.wikipedia.org/wiki/Cavendish_experiment).

http://milesmathis.com/caven.html

What are Miles Mathis's credentials again.  Oh, that's right.  He's an artist.
http://mileswmathis.com/
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 28, 2009, 04:30:31 PM
The varying of boiling temperature with altitude is a conclusive evidence for RE.
How so? The varying of boiling temperature with altitude is entirely explained by pressure variation, and one can show (as I did earlier in this thread) that atmospheric pressure P varies with altitude h in the accelerating FE model according to the law P(h)=P0e-kh (for some constant k, to a reasonable approximation, ignoring effects of weather and temperature variation with altitude). So we would predict, using the FE model, that water should boil at a lower temperature at higher elevations, because the pressure is lower, and water boils at lower temperatures in lower pressures. So it seems to me that the empirical observation of lowered boiling point at altitude is consistent with a flat Earth, and doesn't constitute evidence that the Earth is round.
Title: Re: Proofs of varying gravity
Post by: Tom Bishop on December 28, 2009, 04:32:15 PM
What are Miles Mathis's credentials again.  Oh, that's right.  He's an artist.
http://mileswmathis.com/

From http://fineartstudioonline.com/artists/MilesMathis.html :

Title: Re: Proofs of varying gravity
Post by: ugaboga313 on December 28, 2009, 04:43:06 PM
Nice job Bishop reading your own link. Not only do I doubt what this guy is talking about (E/M fields on what? From what? I think he is kinda crazy) he even says "In other words, the Cavendish machine may give us a misleading motion, but it may give us almost the right numbers anyway."

He even confirms Cavendish machine will give almost accurate results meaning, there is gravity.

Also his talking of E/M fields in this experiment seems incredibly stupid. I have no idea how E/M fields would affect a Lead ball.
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 04:48:35 PM
The varying of boiling temperature with altitude is a conclusive evidence for RE.
How so? The varying of boiling temperature with altitude is entirely explained by pressure variation, and one can show (as I did earlier in this thread) that atmospheric pressure P varies with altitude h in the accelerating FE model according to the law P(h)=P0e-kh (for some constant k, to a reasonable approximation, ignoring effects of weather and temperature variation with altitude). So we would predict, using the FE model, that water should boil at a lower temperature at higher elevations, because the pressure is lower, and water boils at lower temperatures in lower pressures. So it seems to me that the empirical observation of lowered boiling point at altitude is consistent with a flat Earth, and doesn't constitute evidence that the Earth is round.
So, are you arguing for or aginst FE?
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 28, 2009, 04:57:09 PM
So, are you arguing for or aginst FE?
I'm arguing that the variation of pressure with altitude (and by extension, the variation in the boiling point) can be equally well explained in both models, and that therefore the empirical fact that boiling point varies with elevation, alone, does not constitute evidence for either model.
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 05:04:19 PM
Ok, now see the title of this thread and reconsider whether you are posting in the correct thread.
Title: Re: Proofs of varying gravity
Post by: Dino on December 28, 2009, 05:18:40 PM
It could be that the illusion of varying gravity is created by varying degrees of air pressure pushing down upon weighty objects.

As for plumb bobs near mountains, maybe you are correct: down isn't always down; it is in the direction of the most earth. You can call this "center of gravity", but it may better be thought of as "place of most earth". 
Title: Re: Proofs of varying gravity
Post by: Tom Bishop on December 28, 2009, 05:20:13 PM
Quote
Also his talking of E/M fields in this experiment seems incredibly stupid. I have no idea how E/M fields would affect a Lead ball.

E/M fields affect all bodies on small scales.
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 28, 2009, 05:22:58 PM
Ok, now see the title of this thread and reconsider whether you are posting in the correct thread.
I was replying to your egg comment. Only you can explain why you posted that in this thread. When replying to comments in a thread, my tendency is to reply in the thread, rather than create a new one.

In any case, would you care to respond to my argument, rather than quibble about where I posted it?
Title: Re: Proofs of varying gravity
Post by: ugaboga313 on December 28, 2009, 05:37:49 PM
How would E/M effect lead balls? Lead is not magnetic. I doubt the movement of photons makes anywhere near enough momentum to get it going. I don't think that guy was particularly smart.


Even he said that while the experiment had flaws, it would give correct results. Thanks Bishop for helping me.
Title: Re: Proofs of varying gravity
Post by: trig on December 28, 2009, 05:54:13 PM
So, are you arguing for or aginst FE?
I'm arguing that the variation of pressure with altitude (and by extension, the variation in the boiling point) can be equally well explained in both models, and that therefore the empirical fact that boiling point varies with elevation, alone, does not constitute evidence for either model.
This discussion is a good example of a natural phenomenon that does not give nice and easy demonstrations of the shape of the Earth.

While maybe we could construct measuring equipment that measures the pressure of the atmosphere with enough precision to differentiate between the two models (and I am using the term "model" very loosely in the case of "FET") there are other experiments and observations that give better results with a millionth of the effort.

If the FE "model" was right we should see a nice round wall around the known Earth, of about 70,000 feet high. That is several times higher than the Everest. And it would have to be surprisingly invisible. It would, as always, be easy to just travel South on a plane until a really impenetrable barrier is found. But it is easier still to make any number of experiments concerning navigation of a few hundred kilometers, on land, sea or air and tabulate the position of stars, sun, moon and planets.

PS. Remember, the atmosphere is a paper thin layer on top of a huge planet. It would not be wise to expect a stable enough atmosphere to measure such a tiny effect and not confuse it with other phenomenons, like the changing composition of the air at different altitudes.
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 06:36:35 PM
Also his talking of E/M fields in this experiment seems incredibly stupid. I have no idea how E/M fields would affect a Lead ball.
If one of the objects is slightly charged, this will cause electrostatic influence separation of bound charges in the conducting metallic sphere. The closer end would be charged by opposite sign and the farhter end by the like sign. Thus, the attractive force would be slightly  bigger than the repulsive force and there is an effective attraction. Note that this effect does not depend on the sign of the charge of the charged sphere.

I derived an exact expression for the attractive force between a point charge Q and a neutral conducting sphere with radius R a distance d apart:

F = k0*Q2*R3*(2d2 - R2)/(d3*(d2 - R2)2).

When R << d, the lowest order approximation to this formula is:

F = 2*k0*Q2*R3/d5.

We can find for what charge Q is this force comparable to the gravitational force between the spheres:

F = G*M*m/d2
Title: Re: Proofs of varying gravity
Post by: ugaboga313 on December 28, 2009, 07:00:41 PM
Yea I know slight charges would do that but charges are really slight on a lead ball. I'd say that gravity would be far stronger at these distances as weak as it is.
Title: Re: Proofs of varying gravity
Post by: Dino on December 28, 2009, 07:07:50 PM
I dont get this thread at all. Are there really REers here who believe in the reality of gravity, or are you just all pulling our legs? I didnt realize you were a bunch of relativity deniers.

If there are any actual gravity cranks here they should probably start their own site and call it the Gravity Society.
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 07:08:46 PM
Yea I know slight charges would do that but charges are really slight on a lead ball. I'd say that gravity would be far stronger at these distances as weak as it is.

Calculate!
Title: Re: Proofs of varying gravity
Post by: ugaboga313 on December 28, 2009, 07:20:54 PM
Dino are you asking who believes in gravity?

Parsec you could be right that the slight forces negate as I am far too lazy to calculate. I guess I'm wrong on that part but he still says that the experiment works. Bishop really helped out RE with that.
Title: Re: Proofs of varying gravity
Post by: Dino on December 28, 2009, 07:36:01 PM
Dino are you asking who believes in gravity?


Yes, I am asking if there is a single person here who believes in gravity.
Title: Re: Proofs of varying gravity
Post by: Thermal Detonator on December 28, 2009, 07:40:28 PM
I believe in gravity.
Title: Re: Proofs of varying gravity
Post by: Dino on December 28, 2009, 07:45:22 PM
I believe in gravity.


So you are a relativity denier? They arent consistent theories are they?
Title: Re: Proofs of varying gravity
Post by: parsec on December 28, 2009, 08:15:44 PM
Dino are you asking who believes in gravity?

Parsec you could be right that the slight forces negate as I am far too lazy to calculate. I guess I'm wrong on that part but he still says that the experiment works. Bishop really helped out RE with that.

lol, they don't negate! they are both attractive.
Title: Re: Proofs of varying gravity
Post by: markjo on December 28, 2009, 08:34:27 PM
I believe in gravity.

So you are a relativity denier? They arent consistent theories are they?

Don't tell me this is going to degenerate to another pedantic gravity/gravitation discussion.  ::)
Title: Re: Proofs of varying gravity
Post by: Dino on December 28, 2009, 08:53:23 PM
I believe in gravity.

So you are a relativity denier? They arent consistent theories are they?

Don't tell me this is going to degenerate to another pedantic gravity/gravitation discussion.  ::)

Not at all. There is no force of gravity in relativity. And the theories make different predictions. They do not reconcile. Why are the REers here using such an archaic theory, one they know to be wrong? There is no occult gravity force and that there are intelligent people here arguing for one only goes to show they are trolls.
Title: Re: Proofs of varying gravity
Post by: markjo on December 28, 2009, 09:05:37 PM
I believe in gravity.

So you are a relativity denier? They arent consistent theories are they?

Don't tell me this is going to degenerate to another pedantic gravity/gravitation discussion.  ::)

Not at all. There is no force of gravity in relativity. And the theories make different predictions. They do not reconcile. Why are the REers here using such an archaic theory, one they know to be wrong? There is no occult gravity force and that there are intelligent people here arguing for one only goes to show they are trolls.

GR says that mass warps space-time.  Objects following that warping of space-time is what we interpret as the "force" of gravity.  GR may or may not accurately describe the actual mechanism of gravity, but it does work well as a mathematical model of what we experience as gravity.
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 28, 2009, 09:26:24 PM
Not at all. There is no force of gravity in relativity.
Sure there is, in the same way centrifugal force is a real force. Yes, it is an artifact of using certain frames of reference, but in those frames of reference it is a very real force.
Quote
And the theories make different predictions. They do not reconcile. Why are the REers here using such an archaic theory, one they know to be wrong?
They do make different predictions, but those predictions are very close together in most situations, and the force predicted by the Newtonian model is much easier to calculate, so there is nothing wrong with using the Newtonian model in the realm where it gives good predictions.
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 28, 2009, 09:34:29 PM
Here we post conclusive evidence that gravity varies  with height. Let me start:

Sorry, gravity isn't always 'down' it can be in any direction, the deplection of plum bobs near mountains clearly shows this.
That's a quote, which is hardly conclusive evidence. Also, it doesn't seem to refer to height-related variation, but rather deflection owing to large masses (mountains), which is something else entirely. Where is your conclusive evidence that the force of gravity varies with height?

But, these scientists (http://www.physicsforums.com/archive/index.php/t-138568.html) have even calculated the deflection angle.
Yes, they have calculated what the deflection angle would be for a hanging plumb bob on a spherical rotating Earth due to centrifugal force. But nowhere in that thread is any evidence that they have measured said force, so their calculations are evidence of nothing. In any case, since they compute the dependence on latitude, this seems to have little to do with your claimed height-related variation of gravity.

So far, the only thing you seem to have claimed as evidence that gravity depends on height was your boiled egg conundrum. As I have explained, this is due to atmospheric pressure and not gravity, and does not provide evidence that gravity varies with height.
Title: Re: Proofs of varying gravity
Post by: Dino on December 28, 2009, 09:39:48 PM
Not at all. There is no force of gravity in relativity.
Sure there is, in the same way centrifugal force is a real force. Yes, it is an artifact of using certain frames of reference, but in those frames of reference it is a very real force.
Quote
And the theories make different predictions. They do not reconcile. Why are the REers here using such an archaic theory, one they know to be wrong?
They do make different predictions, but those predictions are very close together in most situations, and the force predicted by the Newtonian model is much easier to calculate, so there is nothing wrong with using the Newtonian model in the realm where it gives good predictions.

So REer's prefer models which are "easier to calculate". I agree with this. REer's look for convenient models. They are are biased toward the idea that truth is convenient.

Shouldnt the truth also be true?
Title: Re: Proofs of varying gravity
Post by: Dino on December 28, 2009, 10:22:48 PM
Not at all. There is no force of gravity in relativity.
Sure there is, in the same way centrifugal force is a real force. Yes, it is an artifact of using certain frames of reference, but in those frames of reference it is a very real force.
Quote
And the theories make different predictions. They do not reconcile. Why are the REers here using such an archaic theory, one they know to be wrong?
They do make different predictions, but those predictions are very close together in most situations, and the force predicted by the Newtonian model is much easier to calculate, so there is nothing wrong with using the Newtonian model in the realm where it gives good predictions.

I like this. Arent the predictions of UA right in most situations? But maybe the theory of gravity is more accurate than that. and relativity more accurate than that. then how could one say that gravity AND relativity are true but UA is false? Either they are all varying degrees of true or only one could be true. (Though, likely none are true.)
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 28, 2009, 10:53:57 PM
I like this. Arent the predictions of UA right in most situations?
Oh certainly. Most scientists treat the Earth as flat and gravity as constant (not varying with height) all the time, because locally it's true. That doesn't mean that they think the Earth is flat, only that taking its curvature into account would be a lot of extra work for no actual benefit.

In fact, I was amused to note earlier this evening that the Wikipedia page on atmospheric pressure (http://en.wikipedia.org/wiki/Atmospheric_pressure) treats the Earth's gravity as being constant, and so their theoretical value for the dependence of pressure on altitude is identical to the formula I derived for the flat Earth model.
Title: Re: Proofs of varying gravity
Post by: ugaboga313 on December 29, 2009, 06:19:40 AM
I believe in gravity. It's pretty real to me. In fact it is more real than your silly UA. Why? Because you can measure the slight attraction between two objects or between say a mountain and a plum bob. UA has no provisions for this except ignore it. You are right, the truth should be true.
Title: Re: Proofs of varying gravity
Post by: parsec on December 29, 2009, 07:18:17 AM
I believe in gravity. It's pretty real to me. In fact it is more real than your silly UA. Why? Because you can measure the slight attraction between two objects or between say a mountain and a plum bob. UA has no provisions for this except ignore it. You are right, the truth should be true.
This. You guys stop derailing my thread. Any new ideas as evidence?
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 29, 2009, 08:48:34 AM
I believe in gravity. It's pretty real to me. In fact it is more real than your silly UA. Why? Because you can measure the slight attraction between two objects or between say a mountain and a plum bob. UA has no provisions for this except ignore it. You are right, the truth should be true.
I've seen a lot of claims about this, but no evidence. How do you propose I measure this?
Title: Re: Proofs of varying gravity
Post by: ugaboga313 on December 29, 2009, 08:58:16 AM
http://www.uwsp.edu/geo/faculty/ozsvath/images/plumb_bob_observations.htm

Get yourself a plumb bob and head over to the nearest massive mountain chain. Also the cavendish experiment can show the attraction between 2 objects.
Title: Re: Proofs of varying gravity
Post by: parsec on December 29, 2009, 09:00:44 AM
http://www.uwsp.edu/geo/faculty/ozsvath/images/plumb_bob_observations.htm

Get yourself a plumb bob and head over to the nearest massive mountain chain. Also the cavendish experiment can show the attraction between 2 objects.
Precisely. Irrefutable.
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 29, 2009, 09:33:01 AM
According to accounts of similar experiments on Wikipedia (http://en.wikipedia.org/wiki/Schiehallion_experiment), the magnitude of the deflection I would be looking for is about one half of one percent of a single degree of arc (or about 10 seconds of arc). How do you propose I reliably measure this? Has anyone here actually done this experiment? You seem to be pretty cavalier in your claims that it can be easily performed and this deflection easily detected, but the actual deflection claimed by RE scientists is far less than the experimental error in any measuring device I have or can feasibly make or buy.

If your evidence is an experiment that you haven't performed, that I can't feasibly perform, and that hasn't been performed and described by anyone I can trust, it's hardly irrefutable, and is basically worthless as evidence of anything if you believe in the conspiracy.
Title: Re: Proofs of varying gravity
Post by: ugaboga313 on December 29, 2009, 10:11:23 AM
So you don't trust the link I gave but trust wikipedia? Who do you trust? Get some good equipment and this should be simple. Do multiple trials at different locations with different hardware, and you can eliminate error. If you do this like a real science lab (controls, lots of trials, etc) you can get pretty close to the correct answer.
Title: Re: Proofs of varying gravity
Post by: markjo on December 29, 2009, 10:13:51 AM
So you don't trust the link I gave but trust wikipedia? Who do you trust? Get some good equipment and this should be simple. Do multiple trials at different locations with different hardware, and you can eliminate error. If you do this like a real science lab (controls, lots of trials, etc) you can get pretty close to the correct answer.

Where do you suggest that he find equipment that can measure 10 arc seconds of deflection?
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 29, 2009, 10:37:43 AM
So you don't trust the link I gave but trust wikipedia? Who do you trust?
I trust Wikipedia to mostly report the consensus of interested parties, backed up by citation, and to occasionally contain errors and deliberate misinformation. I don't trust it any further than that, and neither should you. Here I am just using it to find what RE scientists claim the deflection should be according to RE theory, not to prove that one model or another is correct (which should involve an experiment can be performed by me personally or someone I trust, so I don't have to worry about "the conspiracy").

Quote
Get some good equipment and this should be simple. Do multiple trials at different locations with different hardware, and you can eliminate error. If you do this like a real science lab (controls, lots of trials, etc) you can get pretty close to the correct answer.
You can't take an experiment that doesn't work and throw multiple trials at it to make it work. If my experiment isn't sensitive enough to detect the difference between the predictions of FE (no deflection due to gravity from large mountains) and RE (deflection due to gravity from large mountains), performing the same experiment many times is not going to help.

In this thread I was promised "conclusive evidence" that gravity varies based on location. We're now 5 pages into the thread, and still no such evidence has been forthcoming. Please tell me how to perform an experiment that is sufficiently sensitive to detect the difference between the two models, what equipment I will need to perform it, and how I can get that equipment without emptying my bank account (or perform the experiment yourself). Otherwise you should come up with some other evidence, or else stop claiming to have conclusive evidence when all you have is "I read it on the intertubes." Give me five minutes with Google, and I can find equally good evidence of working perpetual motion machines, and much better evidence that homeopathy works.
Title: Re: Proofs of varying gravity
Post by: ugaboga313 on December 29, 2009, 11:43:12 AM
http://www.mansfieldct.org/schools/MMS/staff/hand/lawsgravaltitude.htm

Weigh yourself while flying. Use a sensitive scale. Need anything else?
Title: Re: Proofs of varying gravity
Post by: Mrs. Peach on December 29, 2009, 11:48:26 AM
Yes.  You could ask the pilot to maintain a prefect 1g; I'm sure he'd be delighted to do so even if he was capable.
Title: Re: Proofs of varying gravity
Post by: SupahLovah on December 29, 2009, 12:00:26 PM
Mrs. Peach FTW!
Title: Re: Proofs of varying gravity
Post by: markjo on December 29, 2009, 12:31:27 PM
Yes.  You could ask the pilot to maintain a prefect 1g; I'm sure he'd be delighted to do so even if he was capable.

If the pilot maintained a perfect 1g, wouldn't that kind of defeat the whole purpose of the experiment?
Title: Re: Proofs of varying gravity
Post by: SupahLovah on December 29, 2009, 12:34:27 PM
The point is that flying in a plane can have the effect of nearly any amount of gravity with enough space to fly in
Title: Re: Proofs of varying gravity
Post by: Mrs. Peach on December 29, 2009, 12:42:06 PM
Yes.  You could ask the pilot to maintain a prefect 1g; I'm sure he'd be delighted to do so even if he was capable.

If the pilot maintained a perfect 1g, wouldn't that kind of defeat the whole purpose of the experiment?

The experiment is not feasible was my point.
Title: Re: Proofs of varying gravity
Post by: ugaboga313 on December 29, 2009, 01:06:32 PM
Even easier, Hot Air balloon. Wait for no wind, and you can get a small change in your weight.
Title: Re: Proofs of varying gravity
Post by: markjo on December 29, 2009, 03:07:00 PM
Yes.  You could ask the pilot to maintain a prefect 1g; I'm sure he'd be delighted to do so even if he was capable.

If the pilot maintained a perfect 1g, wouldn't that kind of defeat the whole purpose of the experiment?

The experiment is not feasible was my point.

Actually, you would just need to set the auto-pilot to straight and level flight.  Sounds perfectly feasible to me.
Title: Re: Proofs of varying gravity
Post by: SupahLovah on December 29, 2009, 03:09:38 PM
Sounds like a conspiracy and that teh aeroplain would really be flying toward the FE in such a curve to show a reduction in gravitational pull.
Title: Re: Proofs of varying gravity
Post by: skeptical scientist on December 29, 2009, 03:10:49 PM
Even easier, Hot Air balloon. Wait for no wind, and you can get a small change in your weight.
The world record for hot air balloon altitude is about 20 km (and I'm probably not about to set any world records in ballooning). At that altitude, the difference in gravity relative to sea level is .6% (http://www.google.com/search?q=1-(radius+of+earth/(radius+of+earth+%2B+20+km))%5E2). In other words, to be sure I've detected a reading, I need to know that my balloon is not changing its rate of drifting by as little as .06 m/s2. How do you propose I get a hot air balloon drifting at 20,000 meters that close to stationary? The same applies to commercial airline flights - the plane's trajectory must be exactly level or the experiment is worthless, and I can't know that it is.

You keep proposing experiments to measure variation in gravity, but I'm not sure that you properly understand how minor the variations are that you are trying to measure. The experiments you propose are all likely to have experimental errors which are many times greater than the magnitude of the variation you propose to measure when using equipment available to the general public (and hot air balloons capable of reaching high altitude are not exactly cheap).
Title: Re: Proofs of varying gravity
Post by: Canadark on December 30, 2009, 10:38:32 AM
Not at all. There is no force of gravity in relativity.
Sure there is, in the same way centrifugal force is a real force. Yes, it is an artifact of using certain frames of reference, but in those frames of reference it is a very real force.
Quote
And the theories make different predictions. They do not reconcile. Why are the REers here using such an archaic theory, one they know to be wrong?
They do make different predictions, but those predictions are very close together in most situations, and the force predicted by the Newtonian model is much easier to calculate, so there is nothing wrong with using the Newtonian model in the realm where it gives good predictions.

So REer's prefer models which are "easier to calculate". I agree with this. REer's look for convenient models. They are are biased toward the idea that truth is convenient.

Shouldnt the truth also be true?

So the more complex model is the true one, inconsistencies notwithstanding?
Title: Re: Proofs of varying gravity
Post by: Yousmokecrackz on December 30, 2009, 01:03:14 PM
How about when I try to boil my eggs on a high mountain-top? They're always too soft boiled.

I personally say that the stars have a slight attracting field.

However, other FE proponents vehemently deny any alteration of g at higher altitudes.
I thought FE'ers didnt believe in gravity, and that stars were merely a 'backdrop' painted some precise distance from the Earth?
I read the FAQ some time ago.
Title: Re: Proofs of varying gravity
Post by: Dr Matrix on December 30, 2009, 06:44:34 PM
How about when I try to boil my eggs on a high mountain-top? They're always too soft boiled.

I personally say that the stars have a slight attracting field.

However, other FE proponents vehemently deny any alteration of g at higher altitudes.
I thought FE'ers didnt believe in gravity, and that stars were merely a 'backdrop' painted some precise distance from the Earth?
I read the FAQ some time ago.

Not all FET's reject gravity. See the gravity sticky.
Title: Re: Proofs of varying gravity
Post by: ONEfireELEMENT on January 01, 2010, 11:23:48 PM
I know...How about we take some men up into space and put them on the moon?  That way, we can get pictures of the earth, and measure the moon's gravity to compare.  I've heard somewhere that this might have already happened though.

Or if you fire a rocket straight up that is spewing fuel at a constant rate (kg/s) and put an accelerometer on the rocket, the accelerometer would read  large at first, and slowly drop as you moved away from the earth.  I think this may have been done already too.
Title: Re: Proofs of varying gravity
Post by: Canadark on January 03, 2010, 11:11:37 AM
How about when I try to boil my eggs on a high mountain-top? They're always too soft boiled.

I personally say that the stars have a slight attracting field.

However, other FE proponents vehemently deny any alteration of g at higher altitudes.
I thought FE'ers didnt believe in gravity, and that stars were merely a 'backdrop' painted some precise distance from the Earth?
I read the FAQ some time ago.

Not all FET's reject gravity. See the gravity sticky.

But then wouldn't the Earth crumple into a ball?
Title: Re: Proofs of varying gravity
Post by: Dr Matrix on January 04, 2010, 04:24:29 PM
But then wouldn't the Earth crumple into a ball?

I can appreciate you don't want to read the entire mega-thread that is the gravity sticky to find out the that answer to your question is "no, not necessarily", but if you want to dig up the conversation again I would suggest at least skimming it for relevant nuggets you find particularly objectionable.
Title: Re: Proofs of varying gravity
Post by: trig on January 05, 2010, 04:39:05 AM
But then wouldn't the Earth crumple into a ball?

I can appreciate you don't want to read the entire mega-thread that is the gravity sticky to find out the that answer to your question is "no, not necessarily", but if you want to dig up the conversation again I would suggest at least skimming it for relevant nuggets you find particularly objectionable.
You are asking Canadark to throw himself waist deep into a pile of rubbish to find the particular shell of rotten egg that he finds objectionable?

It has been shown several times that the gravitational pull exerted on the farthest edges of the disk are more than enough to crumple the disk you propose. You can either accept Newton's gravitational pull as close the the mark for all but extreme circumstances or throw it away completely. You cannot choose to believe in a complete model that gives almost perfect predictions for a variety of experiments and observations and just declare you believe in some of it.
Title: Re: Proofs of varying gravity
Post by: Canadark on January 05, 2010, 08:47:06 AM
But then wouldn't the Earth crumple into a ball?

I can appreciate you don't want to read the entire mega-thread that is the gravity sticky to find out the that answer to your question is "no, not necessarily", but if you want to dig up the conversation again I would suggest at least skimming it for relevant nuggets you find particularly objectionable.

 ::)