[Earthisround]

As stated in the FAQ, the force know as gravity doesnt exist, rather what we feel as gravity is the force of the earth accelerating at a rate of 32ft/s/s. If this is the case, how is it that we do not feel an increased force of gravity every second because of the earth's acceleration?

[Woody]

You would be accelerating at the same rate.

[Roundy]

Please look up the Equivalence Principle, it should answer any questions you might have of this nature.  It was Einstein who said that the effect of gravity was equivalent to that of a constant acceleration, not us.

[Earthisround]

thanks for the answers, I was confused about this

[rabinoz]

Please look up the Equivalence Principle, it should answer any questions you might have of this nature.  It was Einstein who said that the effect of gravity was equivalent to that of a constant acceleration, not us.

Yes, I have looked up the Equivalence Principle in the Wiki and elsewhere and maintain that it cannot be legitimately applied to the whole earth.

The article at this website http://worldnpa.org/abstracts/abstracts_6546.pdf
is really a very telling article on the Equivalence Principle and should be read before anyone criticises too severely what I put here.

In its simplest from the FET uses the Equivalence Principle to replace the gravitational field observed on the earth's surface.  I contend that this is not a valid application of the Equivalence Principle.

we [...] assume the complete physical equivalence of a gravitational field and a corresponding acceleration of the reference system.
— Einstein, 1907

This very brief statement of Einstein needs a little qualification.  If the reference system under consideration is not small enough for the gravitational field to be considered constant over its range then there can be no complete physical equivalence.

This is stressed in the fuller presentation of the Equivalence Principle.

An equivalent formulation of the Principle of Equivalence is that at any local (that is, sufficiently small) region in spacetime it is possible to formulate the equations governing physical laws such that the effect of gravitation can be neglected. This in turn means that the Special Theory of Relativity is valid for that particular situation, and this in turn allows a number of things to be deduced because the solution of the equations for the Special Theory of Relativity is beyond the scope of our course, but is not particularly difficult for those trained in the required mathematics.  from http://csep10.phys.utk.edu/astr162/lect/cosmology/equivalence.html

In the case of the earth we can readily measure variations in the gravitational field.  The most obvious is due to altitude and latitude, but there are more subtle variations due to the presence of ore bodies as used in gravimetric surveys for minerals.

As a result this, the concept of Universal Acceleration can replace a gravitational field only if the reference system (the whole earth) is sufficiently small for the gravitational field to be considered constant over the whole system.

This is clearly not satisfied, so the concept of Universal Acceleration cannot be be used to replace the gravitational field.
 and shows quite clearly that UA is simply an invalid substitute for the observed "gravitational field".

I know that TFES attributes these variations to the "gravitational effects of the celestial bodies", as in:

Q: Why does gravity vary with altitude?
A: The moon and stars have a slight gravitational pull.

but this cannot be the cause because these bodies are in constant motion above the earth, yet the variations in  the observed "gravitational field" because these variations are essentially stationary - being due to altitude, latitude and the proximity of massive ore bodies, etc.

[juner]

This is clearly not satisfied, so the concept of Universal Acceleration cannot be be used to replace the gravitational field.
 and shows quite clearly that UA is simply an invalid substitute for the observed "gravitational field".

You say this, but are unable to provide any actual proof of the claim beyond just those words. Nothing in your post proves counter to FET. Better luck next time.

[rabinoz]

This is clearly not satisfied, so the concept of Universal Acceleration cannot be be used to replace the gravitational field.
 and shows quite clearly that UA is simply an invalid substitute for the observed "gravitational field".

You say this, but are unable to provide any actual proof of the claim beyond just those words. Nothing in your post proves counter to FET. Better luck next time.

So, what are you challenging?

• The variations in "g" over the earth's surface have been known for centuries.
• The observed variations are well correlated with altitude and latitude.
• I have yet seen no-one claiming the Einstein's EP is valid for a region with variations in "g".
• Continually moving celestial objects are not a reasonable explanation for the (almost[1]) static variations in "g" observed.

It seems that Flat Earth supporters simply see the earth as flat. Then every other observation is bent to fit this initial premise without independent evidence.

No, I don't need any luck.

In Rowbotham's day the idea of gravity did not fit with his flat earth, so he denies gravity[2] and proposes UA. Now we find problems with that and those holes get papered over without any evidence that these explanations actually explain the variations found.

[1] I say "almost" because even on the globe earth the sun and moon cause extremely slight variations - about 0.52×10⁻⁷ g and 1.1×10⁻⁷ g resp!

[2] Rowbotham denies Newton's gravity, even though Cavendish had independently verified the effect. Since then hundreds of others have performed similar experiments (I have the results of some 61 of these) and well justified Cavendish's result. Rowbotham and other FE proponents attempt to discredit bt ridicule any contrary evidence.

[Roundy]

Please look up the Equivalence Principle, it should answer any questions you might have of this nature.  It was Einstein who said that the effect of gravity was equivalent to that of a constant acceleration, not us.

Yes, I have looked up the Equivalence Principle in the Wiki and elsewhere and maintain that it cannot be legitimately applied to the whole earth.

Irrelevant.

[rabinoz]

Please look up the Equivalence Principle, it should answer any questions you might have of this nature.  It was Einstein who said that the effect of gravity was equivalent to that of a constant acceleration, not us.

Yes, I have looked up the Equivalence Principle in the Wiki and elsewhere and maintain that it cannot be legitimately applied to the whole earth.

Irrelevant.

You say it's irrelevant, but if the gravitational field across the earth is not constant then, with or without the EP, UA cannot ne used to replace gravity, unless you have justifiable reasons for those deviations. Just remember that I was describing only the most obvious "g" variations - there are many more to consider.

Yes, a few facts are quite irrelevant to the Flat Earth! You see the earth looks flat, then change everything else to suit!
Things like: perspective, massive refraction, impossible magnification in the atmosphere, etc, etc!
Then declare any photos and other evidence that goes against the  Flat Earth as fake or lies!

[Roundy]

Please look up the Equivalence Principle, it should answer any questions you might have of this nature.  It was Einstein who said that the effect of gravity was equivalent to that of a constant acceleration, not us.

Yes, I have looked up the Equivalence Principle in the Wiki and elsewhere and maintain that it cannot be legitimately applied to the whole earth.

Irrelevant.

You say it's irrelevant, but if the gravitational field across the earth is not constant then, with or without the EP, UA cannot ne used to replace gravity, unless you have justifiable reasons for those deviations. Just remember that I was describing only the most obvious "g" variations - there are many more to consider.

Yes, a few facts are quite irrelevant to the Flat Earth! You see the earth looks flat, then change everything else to suit!
Things like: perspective, massive refraction, impossible magnification in the atmosphere, etc, etc!
Then declare any photos and other evidence that goes against the  Flat Earth as fake or lies!

It was irrelevant to the OP's question, which had nothing at all to do with variations in g over the surface of the Earth.  I wasn't defending Flat Earth Theory with my response, I was merely answering his question.  If you have something irrelevant to that question that you think is worthy of debate you should probably take it to the proper board.

[Earthisround]

Please look up the Equivalence Principle, it should answer any questions you might have of this nature.  It was Einstein who said that the effect of gravity was equivalent to that of a constant acceleration, not us.

Yes, I have looked up the Equivalence Principle in the Wiki and elsewhere and maintain that it cannot be legitimately applied to the whole earth.

Irrelevant.

You say it's irrelevant, but if the gravitational field across the earth is not constant then, with or without the EP, UA cannot ne used to replace gravity, unless you have justifiable reasons for those deviations. Just remember that I was describing only the most obvious "g" variations - there are many more to consider.

Yes, a few facts are quite irrelevant to the Flat Earth! You see the earth looks flat, then change everything else to suit!
Things like: perspective, massive refraction, impossible magnification in the atmosphere, etc, etc!
Then declare any photos and other evidence that goes against the  Flat Earth as fake or lies!

It was irrelevant to the OP's question, which had nothing at all to do with variations in g over the surface of the Earth.  I wasn't defending Flat Earth Theory with my response, I was merely answering his question.  If you have something irrelevant to that question that you think is worthy of debate you should probably take it to the proper board.

While It was irrelevant to my original question, he was not discussing it at that time, rather discussing something with Junker. From what I can gather (from experience) some FEers seem to lead someone off topic, and come in saying that it is irrelevant to the original question, which is something Junker does a lot with me, instead of answering the questions asked.

[TheTruthIsOnHere]

I've been looking into buoyancy a little bit... and it seems odd that most people accept that in liquid something with less density will be "pushed" to the top... but can't seem to accept that things behave in a similar manner if submerged in a gas (our atmosphere)
Why Gravity ever was postulated seems extraneous to describe the phenomenon we feel as a solid in liquids and gases

[rabinoz]

I've been looking into buoyancy a little bit... and it seems odd that most people accept that in liquid something with less density will be "pushed" to the top... but can't seem to accept that things behave in a similar manner if submerged in a gas (our atmosphere)
Why Gravity ever was postulated seems extraneous to describe the phenomenon we feel as a solid in liquids and gases

This does not explain the greatly varying weights of objects of exactly the same size.

This a bit from my previous quote with a line added:
Another example.  Suppose we have 4 identical cube shaped blocks of 10 cm each side made of 4 different metals.  The following table gives the mass of air for that volume and the masses (and weights) in kilograms:

Material	Mass of 0.001 m3	Weight when in air
Air	0.0012 kg	--
Magnesium	1.80 kg	1.799 kg
Steel	7.85 kg	7.849 kg
Lead	11.37 kg	11.369 kg
Gold	19.36 kg	19.359 kg

Then of course we find that the weight of any of these blocks actually increases if they are weighed in a chamber with very low air pressure.  Yes, we find that increase is 1.2 g! 

No, it's no co-incidence - just old Archimedes popping up again!

[juner]

old Archimedes popping up again!

The same Archimedes who miscalculated the RET circumference of the earth by thousands of miles? Is that who you are really using to defend your stance?

[Earthisround]

old Archimedes popping up again!

The same Archimedes who miscalculated the RET circumference of the earth by thousands of miles? Is that who you are really using to defend your stance?

I don't think that you realize how old and primitive the equipment they were using to measure it was, and how they using the sun and some math to calculate it, not to mention they surprising amount of variables they had to deal with. For a calculation in Archimedes' time, it was very accurate.

[Woody]

old Archimedes popping up again!

The same Archimedes who miscalculated the RET circumference of the earth by thousands of miles? Is that who you are really using to defend your stance?

He was 1% or 15% off depending on which standard of the stadion is used.  Even 15% off for the technology he had available still means he did a pretty good job.

[Pete Svarrior]

Isn't it amazing how low people's standards get when they're asked to evaluate someone they like?

"No, honey, of course you're not fat."
"No, Archimedes, of course your estimations weren't wildly inaccurate."

[Earthisround]

Again, I dont think that you understand how old and inaccurate their equipment was. Archimedes was born in 287 BC and died in 212 BC, over 2000 years ago! The equipment he had on hand compared to the equipment we have today would be like trying to zoom in on the moon with a magnifying glass, rather than using the Hubble space telescope to do it. The fact that we praise him for getting such an accurate estimate for his time does not mean that we praise him because we like him, but because we see how intelligent he was by being able to calculate the earths circumference with such accuracy.

[TheTruthIsOnHere]

Again, I dont think that you understand how old and inaccurate their equipment was. Archimedes was born in 287 BC and died in 212 BC, over 2000 years ago! The equipment he had on hand compared to the equipment we have today would be like trying to zoom in on the moon with a magnifying glass, rather than using the Hubble space telescope to do it. The fact that we praise him for getting such an accurate estimate for his time does not mean that we praise him because we like him, but because we see how intelligent he was by being able to calculate the earths circumference with such accuracy.

What equipment do we have today to measure the Earth's Circumference?

[juner]

Again, I dont think that you understand how old and inaccurate their equipment was. Archimedes was born in 287 BC and died in 212 BC, over 2000 years ago! The equipment he had on hand compared to the equipment we have today would be like trying to zoom in on the moon with a magnifying glass, rather than using the Hubble space telescope to do it. The fact that we praise him for getting such an accurate estimate for his time does not mean that we praise him because we like him, but because we see how intelligent he was by being able to calculate the earths circumference with such accuracy.

But Eratosthenes was born a decade after Archimedes and managed to get it "right." Apparently they made incredible improvements in that generation, but none in the following 2000 years...