The Flat Earth Society
Flat Earth Discussion Boards => Flat Earth Theory => Topic started by: ElTrancy on January 28, 2019, 04:35:40 PM

How does paper fall the way it does? On a Flat Earth there is no gravity, and objects don't fall, the Earth accelerates upwards to it. So have a friend hold a piece of paper and a rock. Now put your hands under them, and simulate what would happen, by bringing your hands up to meet those objects. That's strange...there's no air resistance from the paper... How does this work? Unless objects do fall by some magic of Flat Earth science. Anybody care to explain this?

Whenever you ask a question like this, please remember Einstein's Equivalence Principle (https://en.wikipedia.org/wiki/Equivalence_principle)  at least locally, UA will be indistinguishable from the gravitational model proposed by RET. This is a direct consequence of RET, not FET. Whenever you think you've found a difference that can be locally demonstrated, you're either misunderstanding the physics behind RET (a likely scenario), or you're disproving it (which would be exciting!).
Your confusion stems from a misunderstanding of frames of reference. The Earth, and the air immediately above it, are both accelerating upwards with regard to a hypothetical observer external to UA. As the air accelerates upward, it pushes the piece of paper up, causing the force you're interpreting as air resistance.
This scenario can be easily reframed into a local observer's frame of reference, one that's stationary with regard to the Earth. From that FoR, the Earth and air above it are stationary (by definition), and the piece of paper is affected by a gravitational pseudoforce and drag.

The Equivalence Principle says that gravity operates EXACTLY like a world where the earth is flat and accelerating upwards. This applies to everything from falling pieces of paper to the Doppler Shift of light when light is pointed vertically.
https://wiki.tfes.org/Evidence_for_Universal_Acceleration

The Equivalence Principle says that gravity operates EXACTLY like a world where the earth is flat and accelerating upwards. This applies to everything from falling pieces of paper to the Doppler Shift of light when light is pointed vertically.
https://wiki.tfes.org/Evidence_for_Universal_Acceleration
Why does the rate of acceleration vary?

The Equivalence Principle says that gravity operates EXACTLY like a world where the earth is flat and accelerating upwards. This applies to everything from falling pieces of paper to the Doppler Shift of light when light is pointed vertically.
https://wiki.tfes.org/Evidence_for_Universal_Acceleration
Why does the rate of acceleration vary?
It doesn't. That is based on a misunderstanding of gravimetry.
See: https://wiki.tfes.org/Gravimetry

The Equivalence Principle says that gravity operates EXACTLY like a world where the earth is flat and accelerating upwards. This applies to everything from falling pieces of paper to the Doppler Shift of light when light is pointed vertically.
https://wiki.tfes.org/Evidence_for_Universal_Acceleration
Why does the rate of acceleration vary?
It doesn't. That is based on a misunderstanding of gravimetry.
See: https://wiki.tfes.org/Gravimetry
Corrections based on the earth elliptical shape. Now we know, you told us.

The Equivalence Principle says that gravity operates EXACTLY like a world where the earth is flat and accelerating upwards. This applies to everything from falling pieces of paper to the Doppler Shift of light when light is pointed vertically.
https://wiki.tfes.org/Evidence_for_Universal_Acceleration
Why does the rate of acceleration vary?
It doesn't. That is based on a misunderstanding of gravimetry.
See: https://wiki.tfes.org/Gravimetry
Corrections based on the earth elliptical shape. Now we know, you told us.
If the earth was elliptical/rotating, then it would not be necessary to add in or subtract artificial corrections to the data and reference model based on your latitude, in order to get the data to show what it should show if the earth were round.

The Equivalence Principle says that gravity operates EXACTLY like a world where the earth is flat and accelerating upwards. This applies to everything from falling pieces of paper to the Doppler Shift of light when light is pointed vertically.
https://wiki.tfes.org/Evidence_for_Universal_Acceleration
Why does the rate of acceleration vary?
It doesn't. That is based on a misunderstanding of gravimetry.
See: https://wiki.tfes.org/Gravimetry
Corrections based on the earth elliptical shape. Now we know, you told us.
If the earth was elliptical/rotating, then it would not be necessary to add in or subtract artificial corrections to the data and reference model based on your latitude, in order to get the data to show what it should show if the earth were round. The fact that those corrections are necessary suggests that it is not.
Strangely, it's the opposite. It's precisely why with a rotating oblate spheroid it is necessary to add in or subtract based upon survey corrections to the data and reference model based on your latitude.
(https://www.researchgate.net/publication/323346591/figure/fig2/AS:596996888985600@1519346558018/Exaggerateddifferencebetweenasphereandanellipseofrotationspheroid.png)

The differences by latitude should be expressed in the gravity data. The fact that it needs to be added in artificially shows that you guys generally don't know how these devices work at all when you use this as evidence.

The differences by latitude should be expressed in the gravity data. The fact that it needs to be added in artificially shows that you guys generally don't know how these devices work at all when you use this as evidence.
How come we have scientists investigating the way the earth works and there are a few people who think otherwise and cannot explain it other than on some obscure internet site?

The differences by latitude should be expressed in the gravity data. The fact that it needs to be added in artificially shows that you guys generally don't know how these devices work at all when you use this as evidence.
There's nothing artificial about it. You do tons of surveys at different latitudes, log them. Latitudes have different results. It's like any measurement of anything. Take boiling water. At sea level, water boils at 212 °F. With each 500feet increase in elevation, the boiling point of water is lowered by just under 1 °F. How do we know this? Because people have looked at what the boiling point temperature is at any given altitude.

The differences by latitude should be expressed in the gravity data. The fact that it needs to be added in artificially shows that you guys generally don't know how these devices work at all when you use this as evidence.
There's nothing artificial about it. You do tons of surveys at different latitudes, log them. Latitudes have different results. It's like any measurement of anything. Take boiling water. At sea level, water boils at 212 °F. With each 500feet increase in elevation, the boiling point of water is lowered by just under 1 °F. How do we know this? Because people have looked at what the boiling point temperature is at any given altitude.
If the survey is really capturing the gravity data, as you guys allege, then no correction for latitude would be needed at all. False equivalence. The artificial adjustment by latitude is being added in.
The "they must know!" handwaving and appeals to authority is uncorroborated.
It is well admitted that those values represent the "theoretical" gravity.
From New standards for reducing gravity data: The North American gravity database (https://scholarcommons.sc.edu/cgi/viewcontent.cgi?article=1001&context=geol_facpub) on p.28:
(https://i.imgur.com/jmiGkGL.png)

The differences by latitude should be expressed in the gravity data. The fact that it needs to be added in artificially shows that you guys generally don't know how these devices work at all when you use this as evidence.
There's nothing artificial about it. You do tons of surveys at different latitudes, log them. Latitudes have different results. It's like any measurement of anything. Take boiling water. At sea level, water boils at 212 °F. With each 500feet increase in elevation, the boiling point of water is lowered by just under 1 °F. How do we know this? Because people have looked at what the boiling point temperature is at any given altitude.
If the survey is really capturing the gravity data, as you guys allege, then no correction for latitude would be needed at all. False equivalence. The artificial adjustment by latitude is being added in.
Your "they must know!" handwaving and appeals to authority is uncorroborated.
It is well admitted that those values represent the "theoretical" gravity.
It's not values that represent "theoretical" gravity. This from a North American Gravity Database  Real measurements are taken through many, many surveys and populated in various databases:
"Corrections to Gravity Measurements
In order to arrive at geologically meaningful anomaly values, as series of “corrections” are made to raw observations of differences between gravity measured at a station and a base station. The use of this term is misleading because most of these “corrections” are really adjustments that compensate (at least approximately) for known variations in the gravity field that do not have geological meaning."
https://research.utep.edu/Default.aspx?PageContentID=3948&tabid=38186
The point is, gravity anomalies are detected through surveying and then refined with corrections. It's not like there is one resulting gravity numerical value measurement that is the same all around the globe and then they just add or subtract based upon some arbitrary theoretical value. They find gravity anomalies all over the place. That's pretty much the whole point of surveying and populating the databases.

Form your link:
"gravity readings are corrected for latitude by multiplying the distance a gravity station is north or south of this base station by this gradient"
It is describing an artificial correction to the data. The latitude information is not coming from the gravimeter.
Why would the gravity readings need to be "corrected for latitude" if these surveys could see it?

Form your link:
"gravity readings are corrected for latitude by multiplying the distance a gravity station is north or south of this base station by this gradient"
It is describing an artificial correction to the data. The latitude information is not coming from the gravimeter.
Why would the gravity readings need to be "corrected for latitude" if these surveys could see it?
For the same reason they have corrections for terrain/altitude, among other things. I never said latitude was coming from the device, that's why it's a correction, a refinement. The gravity reading prior to correction is not the same everywhere on the planet  Prior to and regardless of corrections. That's the point.

If the gravimeter can't detect the latitude data, then it is not possible for these gravimeters to survey the earth in the way you are suggesting that they do.

If the gravimeter can't detect the latitude data, then it is not possible for these gravimeters to survey the earth in the way you are suggesting that they do.
Some do. This one has a GPS receiver built in:
(https://scintrexltd.com/wpcontent/uploads/2017/03/CG6new2e1548267309450.jpg)
https://scintrexltd.com/product/cg6autogravgravitymeter/

Why would the gravity readings need to be "corrected for latitude" if these surveys could see it?
The corrections for latitude are not added to the data , it is subtracted from the data as it is taken as a known value as computed. The data wanted is the difference from the expected value showing the anomaly (look up the definition).
No one is actively trying to prove the earth round with a gravimeter (this is known data). The widest use would be in minerals, oil, gas etc exploration. They are mapping out the subsurface by looking at the difference between the measured value and the expected value.

Why would the gravity readings need to be "corrected for latitude" if these surveys could see it?
The corrections for latitude are not added to the data , it is subtracted from the data as it is taken as a known value as computed. The data wanted is the difference from the expected value showing the anomaly (look up the definition).
No one is actively trying to prove the earth round with a gravimeter (this is known data). The widest use would be in minerals, oil, gas etc exploration. They are mapping out the subsurface by looking at the difference between the measured value and the expected value.
Additionally, I was reading somewhere that the data is used in missile trajectory calculations.

Some do. This one has a GPS receiver built in
So it automatically calculates the latitude correction then? I can only assume that you have conceded the discussion.

Some do. This one has a GPS receiver built in
So it automatically calculates the latitude correction then? I can only assume that you have conceded the discussion.
No, it does not. And I do not.

There are three factors to consider (RE model assumed):
1) The earth is ellipsoidal, at the equator, an observer is further away from the centre of gravity than an observer at the poles, causing things to weigh less at the equator.
2) The earth rotates. The centrifugal force at the equator is therefore greater than at the poles causing things to weigh less at the equator.
3) The earth is an imperfect shape of varying density. It can be approximated by a perfect mathematical ellipsoid of uniform density. It is also a dynamic system, new islands are being created through geological processes, land is eroded by wind and tide and we have tides and tectonic shift. Consumer grade GPS devices work from a mathematical ellipsoid because it makes calculation (relatively) easy. Their typical accuracy of +/ a few metres means this is a good enough approximation for everyday use without the need for any further correction.
WGS84 for example uses a reference ellipsoid (a perfect mathematical shape), it also uses a geoid (EGM96), an irregular surface representing the earth's actual gravitational field, broadly speaking the shape the oceans would take if you took away all the land. It only differs from the reference ellipsoid by a relatively small amount (less than 100m anywhere on earth). The actual surface of the earth is different from both of these  Mount Everest for example.
If the earth were a perfect ellipsoid, then you could easily calculate gravity at any latitude, however it isn't so if you want high accuracy, you need to refer to the geoid in your calculations as well.
Just because the earth isn't a perfect shape doesn't make it flat.
(source image below  Wikipedia)
(https://upload.wikimedia.org/wikipedia/commons/5/56/Geoids_sm.jpg)

If the device was capable of capturing the latitude acceleration data then the corrections for latitude would not be necessary.

If the device was capable of capturing the latitude acceleration data then the corrections for latitude would not be necessary.
The device I referenced doesn't capture latitude acceleration data.

If the device was capable of capturing the latitude acceleration data then the corrections for latitude would not be necessary.
The device I referenced doesn't capture latitude acceleration data.
Yes, that's what our Gravimetery article says.

If the device was capable of capturing the latitude acceleration data then the corrections for latitude would not be necessary.
The device I referenced doesn't capture latitude acceleration data.
Yes, that's what our Gravimetery article says.
The device I referenced doesn't capture latitude acceleration data. It captures it's location via GPS but does not correct for latitude.

Tom has seen the data for parts of Europe and Africa which measured gravity at hundreds of locations and it correlated perfectly with latitude so this is nothing new except the mapping of anomalies.
There is an expected gravity amount at every latitude, this is confirmable. When local gravity is not what it is expected to be, this is useful information as it infers a regional effect is causing it more then just the geometric location on the planet. That is recorded as plus/minus the normal expected gravity reading. This is the entire purpose of the studies to find the local anomalies and map them, not to preset gravity readings to confirm a globe to flat Earthers.

The papers on gravimeter surveying show that the corrections for latitude are artificial. What information do you have to contradict it?
Corrections for Latitude
It is asserted that gravimetry has shown trends at different latitudes, and so this is validation of the idea that it is really measuring "gravity". We find that this assertion is unfounded.
From a university course on gravity surveying we read:
http://www.geolamu.org/notes/m1014.htm (Archive)
“ Recall that, if the Earth were an homogeneous ellipsoid, the value of gravity at the surface would be given by:
g = g0 (1 + k1 sin2 ϕ – k2 sin2 2ϕ)
The objective of gravity surveys is to look for deviations from this reference value. ”
If the objective of gravity surveys is merely to look for deviations from a round earth reference model with the vibrating gravity theory, then the final computed number in meters per second squared would becomes meaningless for the purpose of discussion. Any modifications to the reference values are constructed on an entirely theoretical basis.
The above page tells us that there is a theoretical model and that the goal of gravity surveys is to modify that model. Further down we see, among the list of corrections to be made, the latitude correction:
“ Latitude correction: The earth's poles are closer to the centre of the equator than is the equator. However, there is more mass under the equator and there is an opposing centrifugal acceleration at the equator. The net effect is that gravity is greater at the poles than the equator.
For values relative to a base station, gravity increases as you move north, so subtract 0.811 sin(2a) mGal/km as you move north from the base station. (where a is latitude). ”
We read that we are subtracting or adding values to the reference model and the data to make the corrections for latitude, which is very different than using the data to determine the latitude. The claim that the final number is meaningful as evidence to showcase any particular point is shown fallacious.
United Nations University
On p.9 of Seismic Activity, Gravity, and Magnetic Measurements (https://orkustofnun.is/gogn/unugtpsc/UNUGTPSC1613.pdf) (Archive) by LaGeo as part of the United Nations University Geothermal Training Program we read:
“ 3.6 Reduction of data
Gravimeters do not give direct measurements of gravity; rather, a meter reading is taken which is then multiplied by an instrumental calibration factor to produce a value of observed gravity (known as gobs). The correction process is known as gravity data reduction or reduction to the geoid. The various corrections that can be applied are the following. ”
The section goes on to list a number of corrections, including corrections for latitude and elevation, which is not data contained in the measurement readings:
“ Latitude correction (gn)  Correction subtracted from gobs that accounts for earth's elliptical shape and rotation. The gravity value that would be observed if the earth were a perfect (no geologic or topographic complexities) rotating ellipsoid is referred to as the normal gravity. ”
“ Freeair corrected gravity (gfa)  The freeair correction accounts for gravity variations caused by elevation differences in the observation locations ”
These are artificial corrections which are added or subtracted to the data and reference model. If the earth were really elliptical or rotating, then these artificial corrections would not be necessary.

One day we will read: I contacted xxx and explained they were incorrect. They were very grateful and have redesigned their equipment.