[edby]

The chart below illustrates the second problem of Tom’s hypothesis

Let me explain. I constructed the chart using data from the British Geological survey. The blue noisy line represents raw gravimeter observations along latitude 50.9 (which corresponds to Brighton, England e.g.)  There are no corrections of any sort, not for height or latitude or terrain or anything. This is the stuff coming out of the instrument, which is simply measuring acceleration, not ‘gravity’.

Units are the familiar one of m / s sq.

The red noisy line is the same kind of raw data measured at different points along the 55.6 latitude, including Gretna Green in Scotland.

Turning to the green line, this is absolutely straight and represents a theoretical acceleration based on (i) latitude of 50.9 and (ii) average assumed height of 100m. It’s important to understand this line does not use any information from the instrument at all. It’s a purely theoretical function using two inputs, based on the Newtonian theory of gravity. Nothing more. Finally the purple straight line is the same theoretical acceleration for the Scotland latitude.

[edit] Putting it another way, the straight line is saying 'this is what we would expect to see if Newtonian gravity is true and if the earth were approximately spherical, the noisy line is say 'this is what we actually see'.

The problem for the UA theory is to explain how the observed, i.e. totally uncorrected data is different for the different latitudes. No assumptions have been made about ‘gravity’, the shape of the earth, density of rock or anything like that. Simply observed acceleration measured by dropping an object for a certain distance then measuring the time taken.

As for ‘anomaly’, this chart is not showing anomaly, but you could derive the anomaly by subtracting the noisy line from the straight one. It is the confusion about anomaly which has derailed this discussion. Anomaly is not gravity, but rather an observation number (noisy) minus a theoretical number (straight).

[RonJ]

Another source for exactly what a seismometer is:

Seismometers measure the motion or displacement of the ground, a three-component vector u(x,t) that is a function of position x and time t.

In other words a Seismometer measures the motion or displacement vs time of the mass that produces gravity.  That's why you see a gravimeter show changes when there's a motion of the mass because the distance to the mass changes.  The total amount of mass on the earth doesn't change it just moves around a bit.  Yes, you can have some meteorites crash into the earth that adds a bit to the mass, and you can send some mass off into space (maybe not in FET) that will subtract a bit of mass) but for the most part the mass on earth stays constant.  If that mass was uniformly distributed throughout a perfectly spherical earth the force of gravity would be perfectly uniform and wouldn't ever vary.  Of course the earth is an oblate spheroid so there's a change in the force of gravity measured on the surface of that oblate spheroid depending on the measurement location.  Since the mass inside the earth is in constant motion there's always a change in the measured gravity. A gravimeter will see a small change in the measured force of gravity because there's a small change in the distance to the mass that causes the gravity.  The seismometer measures that motion or displacement of mass not really the absolute force of gravity.  If the mass of the earth remained absolutely constant and had zero movement then a gravimeter would show a constant, steady, reading.  A seismometer would show a constant zero reading. 

It's like ringing a bell.   A gravimeter measures the bell --  a seismometer measures the ring

Maybe if you did even a little more research you could show via seismometer readings that the earth is an oblate spheroid, wouldn't that be interesting?
https://arxiv.org/html/physics/0605162


https://www.sciencedirect.com/topics/earth-and-planetary-sciences/seismographs

[Tom Bishop]

Yet another gravimeter = seismometer reference.

From second page of https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/91JB01577



On the same page:



From https://en.wikipedia.org/wiki/Gravity_wave



Also see: https://en.wikipedia.org/wiki/Infragravity_wave

The gravimeter is a seismometer measuring tiny vibrations in the noisy low frequency bands. Analysis performed under the theory that patterns in the noise are due to gravity.

[RonJ]

Your analysis is about 180 degrees out of phase.  A seismometer measures CHANGES in gravity LARGER THAN ZERO.  Those changes can be about any frequency LARGER than zero.  A gravimeter can also measure the changes in gravity but can also measure gravity down to a frequency that INCLUDES ZERO.  A subtle but important difference.  The idea of the gravimeter is to measure the acceleration of one mass caused by the force of attraction of another mass.  That force of acceleration can be a constant or a variable, it doesn't matter, the gravimeter can measure it.  The Idea of a seismometer is to measure the change (not the absolute value of) a mass due to it's physical movement.  If there's NO physical movement of the mass then there will be a ZERO reading on a seismometer but a CONSTANT reading on a gravimeter. 

If you have any gravity at all a gravimeter can measure it.  You have to have a CHANGE in that same gravity for a seismometer to measure it.    Two different devices, two different reasons to have them.

It's kind of like having a AC / DC voltmeter.  You can't really measure a constant DC voltage on an AC meter.  Your reading would be zero.  You can measure a slowly changing AC voltage on a DC meter but you really can't make too much sense out of it but can maybe mentally average the readings to get an idea.    Think of the Gravimeter like a DC voltmeter and a Seismometer like a AC meter.  They are both voltmeters but have different purpose.

A gravimeter can measure the equation y = 2   ... a seisometer can only measure the first derivative of that equation:  dy/dx = 0     A gravimeter would measure 2 and a seisometer would measure zero. 
You can't have two instruments measure the same identical thing and get completely different readings and consider them to be equivalent.

[RonJ]

https://en.wikipedia.org/wiki/Seismology

If you really want to get into Seismology why not pay specific attention to the section in the link above relating to 'Mapping the earth's interior'.  Detailed research will probably lead you to a proof that the earth is spherical just by doing some detailed seismology calculations on the waves produced during an earthquake and how those waves are reflected around on the interior of a sphere.  If the earth were a flat plane the reflections of those waves would be radically different.

[stack]

Lets look at how this gravimeter works:

https://schmidtocean.org/rv-falkor/operations-and-science-systems/gravimeter/#images

The gravimeter, about the size of a steamer trunk, uses magnetism to suspend an internal metal cylinder, and measures changes in the way gravity pulls on that cylinder. Many people are familiar with the fact that acceleration from gravity—for instance if you jump out of a plane—is 9.8 meters per second squared. Measured in milligals (mGals)—a common research unit for gravity—that’s 980,000. Remarkably, the gravimeter can detect changes as small as 1 mGal—or roughly one millionth of gravity’s total pull.

There is no falling object. The magnetism suspends the cylinder. And the system measures changes to that cylinder.

The researchers aren’t interested in that total pull, though; they’re interested in learning about the seafloor. So they process the data coming in to subtract out all the normal weight of Earth below them, which is relatively constant, as well as the weight due to topography, which they get from the sonar mapping.

They don't care about the total pull, they just care about using the device as a seismometer, because it is one, and analyzing the low frequency bands to look for the mass changes.

You're omitting the example of why they are using a gravimeter in the first place. And they are certainly not using it as a seismometer. That is crystal clear:

"What they are left with are differences unique to a given spot. The islands, as you might expect, are filled with the remains of ancient coral reefs—which take the form of relatively light carbonate rock. Using gravity data the team will be able to essentially remove those coral remains to “see” what the geological features below look like. An example of the type of feature the gravimeter can reveal is the fissures on volcanoes known as rift zones where magma comes through during volcanic eruptions. Such fissures are naturally denser than the surrounding rock layers, and yield a stronger and more positive gravity signal."

[Tom Bishop]

A post went missing, you can see it in Stack's post above.

Lets look at how The Global CCS Institute describes gravimetry:

https://hub.globalccsinstitute.com/publications/quantification-techniques-co2-leakage/31-deep-subsurface-monitoring-methods

Gravimetry consists of studying the anomalies of the gravity field due to density variations underground.

It's studying variations due to density underground, based on the theory that gravity would cause fluctuations. Again, similar to what we saw earlier. This is what gravimetry is.

https://en.wikipedia.org/wiki/Gravimetry

Besides precision, stability is also an important property of a gravimeter, as it allows the monitoring of gravity changes. These changes can be the result of mass displacements inside the Earth, or of vertical movements of the Earth's crust on which measurements are being made: remember that gravity decreases 0.3 mGal for every metre of height.

"Changes" was already italicized in the article, because it is emphasizing that the gravimeter is tracking tiny changes and calling it gravity.

https://en.wikipedia.org/wiki/Gravimeter

Many broadband, three axis, seismometers in common use are sensitive enough to track the sun and moon. When operated to report acceleration, they are useful gravimeters. Because they have three axes, it is possible to solve for their position and orientation, by either tracking the arrival time and pattern of seismic waves from earthquakes, or by referencing them to the sun and moon tidal gravity.

Recently, the SGs, and broadband three axis seismometers operated in gravimeter mode, have begun to detect and characterize the small gravity signals from earthquakes.

Again we see that seismometers can operate in gravimeter mode, detecting the slight changes in the noisy low-frequency bands.

You're omitting the example of why they are using a gravimeter in the first place. And they are certainly not using it as a seismometer. That is crystal clear:

"What they are left with are differences unique to a given spot. The islands, as you might expect, are filled with the remains of ancient coral reefs—which take the form of relatively light carbonate rock. Using gravity data the team will be able to essentially remove those coral remains to “see” what the geological features below look like. An example of the type of feature the gravimeter can reveal is the fissures on volcanoes known as rift zones where magma comes through during volcanic eruptions. Such fissures are naturally denser than the surrounding rock layers, and yield a stronger and more positive gravity signal."

A gravimeter is a seismometer. We have seen several researchers telling us that it is. Those "gravity signals" are vibrations detected by that seismometer.

The fact that the call them "gravity signals" and "gravity waves," and we see mentions of gravity and tidal bands makes the situation pretty clear.

[stack]

You're omitting the example of why they are using a gravimeter in the first place. And they are certainly not using it as a seismometer. That is crystal clear:

"What they are left with are differences unique to a given spot. The islands, as you might expect, are filled with the remains of ancient coral reefs—which take the form of relatively light carbonate rock. Using gravity data the team will be able to essentially remove those coral remains to “see” what the geological features below look like. An example of the type of feature the gravimeter can reveal is the fissures on volcanoes known as rift zones where magma comes through during volcanic eruptions. Such fissures are naturally denser than the surrounding rock layers, and yield a stronger and more positive gravity signal."

A gravimeter is a seismometer. We have seen several researchers telling us that it is. Those "gravity signals" are vibrations detected by that seismometer.

The fact that the call them "gravity signals" and "gravity waves," and references to a "gravity bands" makes it perfectly clear.

Is their gravimeter measuring the vibrations of an ancient coral reef or the result of the lower density of the light carbonate deposit, the latter they claim?

[Tom Bishop]

Is their gravimeter measuring the vibrations of an ancient coral reef or the result of the lower density of the light carbonate deposit, the latter they claim?

If seismic vibrations are passing though something, and those signals change slightly when you pass over, it may be possible to subtract some elements to see others through data analysis, just like how they try to use seismic waves to detect tunnels:

https://phys.org/news/2012-12-tunnels-seismic-simple.html

[markjo]

A post went missing, you can see it in Stack's post above.

Lets look at how The Global CCS Institute describes gravimetry:

https://hub.globalccsinstitute.com/publications/quantification-techniques-co2-leakage/31-deep-subsurface-monitoring-methods

Gravimetry consists of studying the anomalies of the gravity field due to density variations underground.

It's studying variations due to density underground, based on the theory that gravity would cause fluctuations. Again, similar to what we saw earlier. This is what gravimetry is.

https://en.wikipedia.org/wiki/Gravimetry

Besides precision, stability is also an important property of a gravimeter, as it allows the monitoring of gravity changes. These changes can be the result of mass displacements inside the Earth, or of vertical movements of the Earth's crust on which measurements are being made: remember that gravity decreases 0.3 mGal for every metre of height.

"Changes" was already italicized in the article, because it is emphasizing that the gravimeter is tracking tiny changes and calling it gravity.

No Tom.  The gravimeter is tracking tiny changes and calling them anomalies, as pointed out in the CSS Institute quote that you cited.

[RonJ]

You didn't read the whole description (probably) of how tunnels are located.  Under the picture of the truck & equipment there was this reference.

"The photo shows some acquisition equipment, including an SUV-mounted accelerated weight drop to generate seismic waves".

There is a good reason for that requirement.  If you want to use a seisometer you have to have a vibration somehow to measure the response.  It would be possible the just wait until there was an earthquake and then analyze the data but that would just take too long.  I'm sure that they set up the seisometer at the location they want to check, then use the accelerated weight on the truck to 'thump' the earth, then measure the vibrations and look in the anomalies generated for the signature of a tunnel.

Again, just another example of the subtle but definite difference between the use & application of a seisometer and a gravimeter.  There are some applications where you could use either a seisometer or a gravimeter.  Other times there are applications were you could ONLY use a gravimeter to obtain the data you need.  It just depends on what you are trying to measure. 

It looks like you could use either a seisometer or gravimeter to show that the earth is an oblate spheroid!       

[Tom Bishop]

Another description:

https://en.wikipedia.org/wiki/Gravity_gradiometry

Gravity gradiometry is the study and measurement of variations in the acceleration due to gravity. The gravity gradient is the spatial rate of change of gravitational acceleration.

Gravity gradiometry is used by oil and mineral prospectors to measure the density of the subsurface, effectively by measuring the rate of change of gravitational acceleration (or jerk) due to underlying rock properties. From this information it is possible to build a picture of subsurface anomalies which can then be used to more accurately target oil, gas and mineral deposits. It is also used to image water column density, when locating submerged objects, or determining water depth (bathymetry). Physical scientists use gravimeters to determine the exact size and shape of the earth and they contribute to the gravity compensations applied to inertial navigation systems.

[stack]

Another description:

https://en.wikipedia.org/wiki/Gravity_gradiometry

Gravity gradiometry is the study and measurement of variations in the acceleration due to gravity. The gravity gradient is the spatial rate of change of gravitational acceleration.

Gravity gradiometry is used by oil and mineral prospectors to measure the density of the subsurface, effectively by measuring the rate of change of gravitational acceleration (or jerk) due to underlying rock properties. From this information it is possible to build a picture of subsurface anomalies which can then be used to more accurately target oil, gas and mineral deposits. It is also used to image water column density, when locating submerged objects, or determining water depth (bathymetry). Physical scientists use gravimeters to determine the exact size and shape of the earth and they contribute to the gravity compensations applied to inertial navigation systems.

Yes, it seems you keep finding research, definitions, etc., of areas of application/study and the instruments used to measure gravity.

[Tom Bishop]

Yes, it seems you keep finding research, definitions, etc., of areas of application/study and the instruments used to measure gravity.

How does the measurement of tiny jerks equal a measurement of gravity? I would really like to know.

[inquisitive]

Yes, it seems you keep finding research, definitions, etc., of areas of application/study and the instruments used to measure gravity.

How does the measurement of tiny jerks equal a measurement of gravity? I would really like to know.

You need to join a science forum, this is not the place to find out.

[stack]

Yes, it seems you keep finding research, definitions, etc., of areas of application/study and the instruments used to measure gravity.

How does the measurement of tiny jerks equal a measurement of gravity? I would really like to know.

Wow, you want to hang your 'gravity can't be measured' hat on the word "jerk"? Interesting. And you're misrepresenting the term by adding your modifier of "tiny" which is not indicated at all. As if indicating constant movement/vibration. Again, not stated at all by what you cite. 

"In physics, jerk is the rate of change of acceleration; that is, the time derivative of acceleration, and as such the second derivative of velocity, or the third time derivative of position. According to the result of dimensional analysis of jerk, [length/time3], the SI units for its magnitude are m/s3 (or m⋅s−3); this can also be expressed in standard gravity per second (g/s)."

https://en.wikipedia.org/wiki/Jerk_(physics)

As we've seen from the countless articles/papers posted here, gravimetry and seismology both factor time as a part of acceleration, or 'jerk'. The former relies more on duration whereas the latter is more attune to the acute aberrations and both measured/used accordingly.

Sorry, but you're going to have to try harder to debunk gravimetry and the instruments used.

[edby]

Tom, you still haven’t addressed the objection I showed earlier, namely that the observed acceleration is different in Gretna (Scotland) than it is in Brighton (Southern England). I.e. the pure observed acceleration without any adjustments for height, latitude, terrain etc. The first showed 9.81539, the second 9.81124

Is the problem that you don’t trust the highly developed and complex instruments discussed in the articles you link to? Then why not a Zetetic experiment of the kind shown here:




The method isn’t particularly accurate, but should be enough to detect the different accelerations observed in Scotland and in England.

Or even better, construct one experiment in London and one where you live. I estimate at your latitude you would see an acceleration of 9.79867, if the Newtonian theory is true. But if UA is true, you would see the same value as where I live. We could repeat the experiment at widely different latitudes.

How about that challenge?

[RonJ]

If you are a weather man and go outside and look at your weather vane on a windy day I'll bet you will see it violently jerking back & forth.  Aren't you still measuring the movement of air?  Usually you just watch the weather vane jerk back & forth and take a mental average and call that the direction of the wind.  When you go down to the sea shore and look at the ocean water don't you usually see a bunch of waves?  If you try to measure the height of the water on a pier piling don't you usually see a lot of violent 'jerky' changes?  You are still measuring the water level, right?  Gravity is like that as well.  It's not a nice steady phenomenon.  The earth can be a chaotic place both above the surface and below.  Any changes below the surface of the earth will produce lots of changes in the gravity field just like a weather vane reacts to the changes in the wind.  Of course you can't see gravity like you can see the waves.  You can't see 'temperature' either, but you can measure it and feel it. You will need some instruments to give you a measurement but just because that measurement varies a lot doesn't mean you are not still measuring gravity.

[edby]

If you are a weather man and go outside and look at your weather vane on a windy day I'll bet you will see it violently jerking back & forth.  Aren't you still measuring the movement of air?  Usually you just watch the weather vane jerk back & forth and take a mental average and call that the direction of the wind.  When you go down to the sea shore and look at the ocean water don't you usually see a bunch of waves?  If you try to measure the height of the water on a pier piling don't you usually see a lot of violent 'jerky' changes?  You are still measuring the water level, right?  Gravity is like that as well.  It's not a nice steady phenomenon.  The earth can be a chaotic place both above the surface and below.  Any changes below the surface of the earth will produce lots of changes in the gravity field just like a weather vane reacts to the changes in the wind.  Of course you can't see gravity like you can see the waves.  You can't see 'temperature' either, but you can measure it and feel it. You will need some instruments to give you a measurement but just because that measurement varies a lot doesn't mean you are not still measuring gravity.

The analogy with wind is a bit misleading, given the amplitude of variation from the average. E.g. I live in a country where the prevailing wind is SW, but this can vary from about nothing, to 50 mph. The gravity 'wind' is more like a river with no tidal variation and which flows in a constant stream with only tiny tiny variations faster and slower. In the case of 'gravitational' acceleration, a constant stream of e.g. 981,164,767 where I live, with variations of 1 to 10 around that average. Variations that only the most accurate instruments in the world can detect.

[RonJ]

Fair enough.  I was just trying to think of something that would make some sense.  If you were just measuring gravity in a static location on a day to day basis I wouldn't much variation at all.  However if you put a gravimeter on a ship or aircraft then you will see a lot more 'jerks' as you pass over the surface of the earth.  Of course all those 'jerks' would be a few places to the right of the decimal point and there wouldn't be any huge change until you started traveling some distance to the North or South.  I read most of the links Tom referred to and found a lot of information that was interesting.  Many of the links refer to the earth as an oblate spheroid with gravity.

Your proposed experiment is interesting but would essentially show the same thing as the Gnome experiment.  If Tom actually got out and personally did the experiment at a lot of different locations maybe that would change things.  It seems that the Zetetic way is to only trust in the evidence that you have accumulated with your own eyes.