Easy test to Disprove Flat Earth

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Easy test to Disprove Flat Earth
« on: December 29, 2009, 04:51:47 PM »
There is one that almost anyone can do. In a plane, your weight will be about 1% lower due to less gravity. FE doesn't explain this.

 

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skeptical scientist

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Re: Easy test to Disprove Flat Earth
« Reply #1 on: December 29, 2009, 05:42:42 PM »
There is one that almost anyone can do. In a plane, your weight will be about 1% lower due to less gravity. FE doesn't explain this.
First of all, no it won't. Assuming the Earth is a round ball with radius 6,378 km, and gravity is a 1/r2 force, then the weight reduction in an airplane is much less than that. In fact, typical airline cruising altitude is about 9 km, with 12 km being about the maximum rated altitude [source]. At 12 km, the percent weight reduction is only .4%.

Secondly, you can't actually perform the experiment to the needed precision needed to prove that gravity varies with altitude. The influence of the .4% deviation in the force of gravity that you need to detect is the same order of magnitude of the effect of the plane itself accelerating up or down at .4%g, or .04 m/s2. That means if the plane is maintaining constant altitude one second, and gains 4 cm of altitude the next (during which time it will have traveled about 250 meters horizontally), the effect of that acceleration on your weight renders the experiment meaningless. An airplane is just not a stable enough platform to perform this experiment. You'll never reach the accuracy needed to detect the variation in gravity predicted by Newton's theory.

Edit: But if you like, I'm flying from Seattle to Chicago on Saturday, and I can perform this experiment for you. All I have is a balance scale; that will work, right? ;)
« Last Edit: December 29, 2009, 05:47:54 PM by skeptical scientist »
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Re: Easy test to Disprove Flat Earth
« Reply #2 on: December 29, 2009, 05:45:23 PM »
Then don't weigh yourself, use a known massive object. Use a hot-air balloon or whatever. This is something that will relatively prove or disprove gravity. Or set up a weather balloon to feed you the weight of an attached iron ball and let it go.

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Tom Bishop

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Re: Easy test to Disprove Flat Earth
« Reply #3 on: December 29, 2009, 05:56:05 PM »
Then don't weigh yourself, use a known massive object. Use a hot-air balloon or whatever. This is something that will relatively prove or disprove gravity. Or set up a weather balloon to feed you the weight of an attached iron ball and let it go.

So now we have to build weather balloons and floating mechanical science labs?

I thought you said it was going to be an easy test.  ???
« Last Edit: December 29, 2009, 05:57:41 PM by Tom Bishop »

Re: Easy test to Disprove Flat Earth
« Reply #4 on: December 29, 2009, 05:58:47 PM »
It is. Weigh yourself along with a heavy object to get your weight up. Use an accurate scale, do it multiple times when you have reached cruise altitude. Should be different than you + heavy object on ground.

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Tom Bishop

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Re: Easy test to Disprove Flat Earth
« Reply #5 on: December 29, 2009, 06:04:24 PM »
If it's so easy to make a controlled weather balloon science lab which can stay perfectly motionless in the upper atmosphere, feel free to go ahead and make it.

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Re: Easy test to Disprove Flat Earth
« Reply #6 on: December 29, 2009, 06:12:30 PM »
Then don't weigh yourself, use a known massive object. Use a hot-air balloon or whatever. This is something that will relatively prove or disprove gravity. Or set up a weather balloon to feed you the weight of an attached iron ball and let it go.
I have already covered this in the other thread, where you already proposed this experiment. Hot-air balloon, weather balloon, whatever - none of them will be a stable enough platform to perform the experiment, because the fluctuation in weight due to the balloon drifting up and down will provide enough noise to override the effect of reduced gravity. Remember, we're talking about a fraction of a percent here; by contrast, your weight can change by more than 10% when riding in an elevator.

It is. Weigh yourself along with a heavy object to get your weight up. Use an accurate scale, do it multiple times when you have reached cruise altitude. Should be different than you + heavy object on ground.
The weight of the person/object being weighed and the accuracy of the scale do not matter when the biggest source of experimental error is the motion of the plane/balloon, and that alone is enough to render the experiment meaningless.
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Re: Easy test to Disprove Flat Earth
« Reply #7 on: December 29, 2009, 06:43:08 PM »
So even a plane at cruise with all the fancy gadgets on won't be level enough for you? Only if something accelerates would it change the value. Why don't you get a blimp and get it to stop accelerating? It isn't that hard.

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Re: Easy test to Disprove Flat Earth
« Reply #8 on: December 29, 2009, 06:56:49 PM »
So even a plane at cruise with all the fancy gadgets on won't be level enough for you? Only if something accelerates would it change the value. Why don't you get a blimp and get it to stop accelerating? It isn't that hard.
News flash: the air isn't that still. Ever hear of turbulence? Even in air which is still enough that there is no noticeable turbulence, there may still be turbulence which is too minor to be felt, but still large enough to ruin this extremely sensitive experiment. Remember the order of magnitude we're talking about: a 4 cm/s change in velocity over the course of a second will throw it off. When we're talking about planes traveling at 6000 times that speed, a cm/s change in velocity is nothing. Similarly, when we're talking about a balloon or blimp being buffeted by winds at high altitude, a 4 cm/s change in velocity is nothing.

To get a sense of how an extremely minor disturbance can throw off the whole experiment, try standing on your bathroom scale. How still do you have to remain in order for your motions not to affect the reading of the scale? Personally, I can't stand that still even when I'm standing still on solid ground - the scale typically fluctuates by 2-3 lbs (which is a fair bit more than .4% of my weight). How hard do you think it would be to get a balloon to stay that still in high altitude winds?

Detecting a .4% variation in gravity requires a very stable place to perform the experiment. No flying device invented by man is going to be that stable in Earth's atmosphere.
« Last Edit: December 29, 2009, 07:57:54 PM by skeptical scientist »
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Re: Easy test to Disprove Flat Earth
« Reply #9 on: December 29, 2009, 06:59:17 PM »
Do tell why a change in velocity is bad? Get a nice digital scale. I thought only acceleration would mess up the results.

Re: Easy test to Disprove Flat Earth
« Reply #10 on: December 29, 2009, 07:08:28 PM »
http://www.npl.co.uk/reference/faqs/i-feel-%27lighter%27-when-up-a-mountain-but-am-i-(faq-mass-and-density)

That's enough (you would appear .03 kg lighter at 3000m) to measure and you can go up higher and higher. You can get to .06 on a high mountain (say double that height) and 60 grams is enough to be measured.


Sorry that it is a little bit harder than the original test was supposed to be.

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Re: Easy test to Disprove Flat Earth
« Reply #11 on: December 29, 2009, 07:36:48 PM »
Do tell why a change in velocity is bad? I thought only acceleration would mess up the results.
Seriously? Do you know what acceleration is?

Acceleration = rate of change of velocity. If the velocity is changing, there's acceleration.
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Re: Easy test to Disprove Flat Earth
« Reply #12 on: December 29, 2009, 07:45:13 PM »
O shit major brain spasm. I kept thinking you were saying a change in position. >_<. You have me on the feasibility of this experiment but my mountain version does seem to work.

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Re: Easy test to Disprove Flat Earth
« Reply #13 on: December 29, 2009, 08:02:57 PM »
http://www.npl.co.uk/reference/faqs/i-feel-%27lighter%27-when-up-a-mountain-but-am-i-(faq-mass-and-density)

That's enough (you would appear .03 kg lighter at 3000m) to measure and you can go up higher and higher. You can get to .06 on a high mountain (say double that height) and 60 grams is enough to be measured.


Sorry that it is a little bit harder than the original test was supposed to be.
Yeah, that would work. It's actually quite a bit harder than you might think to find a scale that measures accurately to within one part in a thousand, but they can be had for under $100.
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Re: Easy test to Disprove Flat Earth
« Reply #14 on: December 29, 2009, 08:05:43 PM »
Anyone live near any tall mountains and has a super awesome scale or has 100 dollars burning a whole in their pocket? Want to prove or disprove gravity?

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Lord Wilmore

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Re: Easy test to Disprove Flat Earth
« Reply #15 on: December 30, 2009, 06:49:56 AM »
The model used by John Davis accounts for this.
"I want truth for truth's sake, not for the applaud or approval of men. I would not reject truth because it is unpopular, nor accept error because it is popular. I should rather be right and stand alone than run with the multitude and be wrong." - C.S. DeFord

Re: Easy test to Disprove Flat Earth
« Reply #16 on: December 30, 2009, 07:00:42 AM »
Why do FE'ers always post half posts which require me asking what they are talking about? So what is this model and may I have a link to it?

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Lord Wilmore

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Re: Easy test to Disprove Flat Earth
« Reply #17 on: December 30, 2009, 07:05:14 AM »
Why do FE'ers always post half posts which require me asking what they are talking about? So what is this model and may I have a link to it?


Because we assume that you've read the FAQ?
"I want truth for truth's sake, not for the applaud or approval of men. I would not reject truth because it is unpopular, nor accept error because it is popular. I should rather be right and stand alone than run with the multitude and be wrong." - C.S. DeFord

Re: Easy test to Disprove Flat Earth
« Reply #18 on: December 30, 2009, 07:08:33 AM »
Q: "Why does gravity vary with altitude?"

A: The heavenly bodies have a slight gravitational pull. However, not all FE'ers believe that gravity varies with altitude.

That is all it says. How close and dense would the heavenly bodies be to have that gravity? Also how is earth somehow absent from gravity? This theory makes no sense.

Edit: I know you are gonna quote the next line after that but that in itself is just a deflection. Matter has gravity. Earth is a form of matter. Why doesn't it have gravity? Unless the heavens don't have gravity and my test is once again valid.

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Lord Wilmore

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Re: Easy test to Disprove Flat Earth
« Reply #19 on: December 30, 2009, 07:16:29 AM »

In John Davis's model, the Earth is an infinite plane and is 9000 kilometers deep.

. . .

A3: In John Davis's model, the infinite plane produces a finite gravitational field with a downward pull. Here is the mathematical formulation behind this model.
"I want truth for truth's sake, not for the applaud or approval of men. I would not reject truth because it is unpopular, nor accept error because it is popular. I should rather be right and stand alone than run with the multitude and be wrong." - C.S. DeFord

Re: Easy test to Disprove Flat Earth
« Reply #20 on: December 30, 2009, 07:21:02 AM »
So I assume this infinite disc is not moving or spinning as that would take infinite energy? How do explain pendulums and the Coriolis effect?

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markjo

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Re: Easy test to Disprove Flat Earth
« Reply #21 on: December 30, 2009, 08:10:32 AM »
The model used by John Davis accounts for this.
Does that mean that the FE model used by John Davis is correct and all other FE models are wrong?
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skeptical scientist

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Re: Easy test to Disprove Flat Earth
« Reply #22 on: December 30, 2009, 08:42:54 AM »
The model used by John Davis accounts for this.
Not true. John Davis's model is that the Earth is an infinite flat plane with Newtonian gravity, and the gravity from an infinite flat plane does not depend on height. So if height-dependence is conclusively demonstrated, it takes out both the UA model and John Davis's model.
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Lord Wilmore

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Re: Easy test to Disprove Flat Earth
« Reply #23 on: December 30, 2009, 09:32:10 AM »
The model used by John Davis accounts for this.
Not true. John Davis's model is that the Earth is an infinite flat plane with Newtonian gravity, and the gravity from an infinite flat plane does not depend on height. So if height-dependence is conclusively demonstrated, it takes out both the UA model and John Davis's model.


Bolded.
"I want truth for truth's sake, not for the applaud or approval of men. I would not reject truth because it is unpopular, nor accept error because it is popular. I should rather be right and stand alone than run with the multitude and be wrong." - C.S. DeFord

Re: Easy test to Disprove Flat Earth
« Reply #24 on: December 30, 2009, 10:00:54 AM »
I have an easy experiment to do with it. Get sensitive mass, and a known weight, and have fun.

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Re: Easy test to Disprove Flat Earth
« Reply #25 on: December 30, 2009, 10:46:40 AM »
The model used by John Davis accounts for this.
Not true. John Davis's model is that the Earth is an infinite flat plane with Newtonian gravity, and the gravity from an infinite flat plane does not depend on height. So if height-dependence is conclusively demonstrated, it takes out both the UA model and John Davis's model.


Bolded.
Ok, fair enough, as far as I know nobody on these forums has ever performed an experiment to measure gravity dependence on elevation, so it's still just a hypothetical test that could be used to determine whether the FE model is consistent with reality on that score. All we have right now is an experiment which could be performed given a sufficiently sensitive spring scale (not a balance scale) and someone willing to weigh a one kilogram mass twice: near sea level and near 3,000 meters elevation, on stable ground.

But if that was your objection, I think I must have misunderstood your comment. When you said that John Davis's model "accounts for this," I thought you were referring to the dependence of gravity on elevation. If that wasn't what you meant, what did you mean by that comment? What exactly is the "this" that John Davis's model accounts for?
« Last Edit: December 30, 2009, 10:58:12 AM by skeptical scientist »
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Lord Wilmore

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Re: Easy test to Disprove Flat Earth
« Reply #26 on: December 30, 2009, 11:11:47 AM »
I agree.  UA has a b unch of issues that need to be resolved before it is taken seriously.

Yeah. 'Cos everyone is taking you seriously... ::)

(Hey gravity varies with altitude too! OMG I NOE)
Yes, gravity does vary with altitude somewhat, due to the heavens, local differences in geography, etc. 
"I want truth for truth's sake, not for the applaud or approval of men. I would not reject truth because it is unpopular, nor accept error because it is popular. I should rather be right and stand alone than run with the multitude and be wrong." - C.S. DeFord

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Re: Easy test to Disprove Flat Earth
« Reply #27 on: December 30, 2009, 11:32:28 AM »
Yes, gravity does vary with altitude somewhat, due to the heavens, local differences in geography, etc. 
I see. Well, he says that gravity varying with altitude is consistent with his model, but never explains how or why, so I don't think it's fair to say that his model accounts for it (unless he has a more detailed explanation elsewhere that I am not aware of). As far as I understand his model, it should predict that gravity does not depend on altitude.
« Last Edit: December 30, 2009, 02:14:24 PM by skeptical scientist »
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Re: Easy test to Disprove Flat Earth
« Reply #28 on: December 31, 2009, 03:21:35 AM »

In John Davis's model, the Earth is an infinite plane and is 9000 kilometers deep.

. . .

A3: In John Davis's model, the infinite plane produces a finite gravitational field with a downward pull. Here is the mathematical formulation behind this model.

If a human being jumps into the air with X amount of force, that force is countered by the force of gravity which causes an acceleration of 9.81/(M)s^2
toward the ground, making a person hit at a given speed. However, since the distance of an object from the surface, over a given amount of time, can effect
the velocity of the object, as acceleration is the change in velocity over time, it is either the object that is accelerating, or the plane,
toward which the object is falling. Let us propose, however, that 2 objects are falling. One object is falling at the acceleration of gravity, and one is
countering the force of gravity with thrust in the opposite direction. The objects velocity towards the ground ever increases as shown by a logarithmic
progression of change in position due to gravity and terminal velocity. However, the object that counters the acceleration of the force of gravity stays parallel to the surface. If this is true,
then either the amount of energy the object is using to oppose the force is increasing at the same rate as the change of position of the falling object,
with respect to the ground, or the ground itself is stationary, and the objects move toward a constant force.

Occam razor time.


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skeptical scientist

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Re: Easy test to Disprove Flat Earth
« Reply #29 on: January 01, 2010, 11:19:25 AM »

In John Davis's model, the Earth is an infinite plane and is 9000 kilometers deep.

. . .

A3: In John Davis's model, the infinite plane produces a finite gravitational field with a downward pull. Here is the mathematical formulation behind this model.

If a human being jumps into the air with X amount of force, that force is countered by the force of gravity which causes an acceleration of 9.81/(M)s^2
toward the ground, making a person hit at a given speed. However, since the distance of an object from the surface, over a given amount of time, can effect
the velocity of the object, as acceleration is the change in velocity over time, it is either the object that is accelerating, or the plane,
toward which the object is falling. Let us propose, however, that 2 objects are falling. One object is falling at the acceleration of gravity, and one is
countering the force of gravity with thrust in the opposite direction. The objects velocity towards the ground ever increases as shown by a logarithmic
progression of change in position due to gravity and terminal velocity. However, the object that counters the acceleration of the force of gravity stays parallel to the surface. If this is true,
then either the amount of energy the object is using to oppose the force is increasing at the same rate as the change of position of the falling object,
with respect to the ground, or the ground itself is stationary, and the objects move toward a constant force.

Occam razor time.


I responded to this argument in the proof that.. thread. Please don't copy-paste the same post into multiple threads, since then I don't know where to respond.
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