741

Flat Earth Theory / Re: Gravity - measurement and applications

« on: September 18, 2020, 01:11:20 AM »

We might be getting closer here, cause yeah that's exactly what isostacy says. And it's not nonsense at all... put enough mass of something and it will start to do work to something beneath it, regardless of their relative densities.

Think snowflakes slowly compressing underlying snow into denser glacier ice, sediments slowly compacting and lithifying underlying layers into rock, and ice cube in a glass of water, or a bunch of colliding low density continental crust deforming the contact with the underlying denser mantle (pictured above and circles in purple in your post)

I would just caution that the diagram is a 3D conceptual model and is no way drawn to scale, so in this case your blue circle isnt really meaningful.

742

Flat Earth Theory / Re: Gravity - measurement and applications

« on: September 16, 2020, 08:15:55 PM »

You're right, not all mountain chains form in the same way.
This site is the only place I've seen the term 'fold mountains'
The upper mantle has high (not low) density material.
You "would expect..." what are you basing your expectations on? Logic? Common sense? Willful optimism?
That quote from quora(?) Mixes up continent-continent orogenic belts with subduction belt orogenies.
Those negative anomalies exist because when you pile up a bunch of low-density material, it pushes down the underlying high-density material, making the dense stuff relatively further away from the measuring device, creating a weaker observed pull.
It's not coincidence - its correlation.

743

Flat Earth Theory / Re: Gravity - measurement and applications

« on: September 16, 2020, 06:35:25 PM »

I'm starting to worry that the flaws you perceive related only to your lack of understanding gravity, mass, and density... you seem to be implying that it's not plausible that something less dense can push down something more dense.  Ice is less dense than water. We know this because ice floats ...if you have a glass of water and place an ice cube into it, the ice cube doesnt sit on top of the water, it deforms it, displacing it around it.

That's obviously an oversimplification, but it still holds: for mountains, less dense rocks are thrust together and accumulate to greater thicknesses, thus adding more mass, which deforms the underlying mantle boundary downward. During glaciation, several kilometers of ice accumulates on top of the crust deforming/compressing it over thousands of years. As the ice melts and retreats, that mass is removed and the crust rebounds back to equilibrium.

744

Flat Earth Investigations / Re: Thork's Jack Russell challenge

« on: September 16, 2020, 05:59:17 PM »

Those are high stakes! All I know is that my dumb black lab wouldn't make the fast dogs list. ...except in the water.

If a lie is repeated enough it definitely starts to get viewed as truth. Good examples are famous movie/TV quotes that are actually misquotes...

I'll get out of your book room now.

745

Flat Earth Theory / Re: Gravity - measurement and applications

« on: September 16, 2020, 11:42:23 AM »

Your inability to understand how the process works - despite my numerous explanations above - does not invalidate it.

Collecting the field data within a given survey area in the form of mapping and sampling surface materials, conducting additional geophysical surveys, and drilling boreholes so we can measure the properties of different rock and sediment units, reduces the number of potential solutions to the gravity data to a point where we can confidently and accurately map the feature.

A gravity survey on it's own can give a good - but not unique - view of the distribution of mass beneath the ground. A good example is that a gravity survey on it's own can tell us where a buried valley is located (because theres less mass in the valley than on either side of it). But it doesnt tell us enough details on what's IN it. If I'm looking for new water supply for a city, the gravity data essentially tells me where to drill to look for an aquifer. If these gravity lows didnt always show geologists where valleys were, we would have stopped using the method decades ago. But it consistently works, so we keep using it.

Drillers comminly ask me what were going to go through in the next 5 feet down a borehole... I always tell them that if I knew for sure, we wouldn't have called them. Geologic data constrains geophysical interpretations. The more geologic data you have, the more accurate your geophysical interpretations can be.

746

Flat Earth Theory / Re: Gravity - measurement and applications

« on: September 16, 2020, 03:04:17 AM »

You're describing things as if they're somehow a detriment. As I said from the beginning, the utility of the gravity measurements in exploration settings comes from the rigorous geoundtruthing and subsequent analysis of the physical properties of the materials that are intersected in boreholes/mines/excavations.

You can try to make is as abstract as you want, since gravity measurements are part of a potential field and, on their own, provide non-unique solutions...but the fact of the matter is that we go and check. Seismic reflection surveys delineate the geometry of units. Boreholes drilled allow us to measure the physical properties. Downhole geophysical tools all us to measure physical properties and take photos and videos of the materials in-situ.  The gravimeters record different pull forces in different places. The magnitude of the differences is much greater than the magnitude of the noise. We learn about what causes the changing pull forces by measuring the properties of the subsurface directly. Together, these data collectively tell us that areas with more mass create stronger  downward pull force. This is strong support that gravity is the pull force a gravimeter measures and the varying strength of gravity/ measured pull force is inexplicable within a framework involving uniform upward acceleration.

747

Flat Earth Theory / Re: Gravity - measurement and applications

« on: September 15, 2020, 12:16:09 PM »

That was a pretty misleading recap.
The noise in the experiment was 0.0001% of a typical signal, which are usually on the order of a few mGal.
You keep saying 'dampen' but you should be saying 'reduced'. The measured pull was reduced in the experiments when a large mass was placed above the gravimeters.
In your last proposition, your right, it is a good idea. In this case, the measured pull would be increased, due to the underlying mass (again, not dampened).

These are very sensitive instruments that measure noise within the signal. Depending on the magnitude of the signal you're measuring, that can become problematic something with a very low amplitude, like say, the pull from Jupiter, could potentially get lost within the ambient noise the device measures. Something with larger amplitudes, like buried valleys and ore deposits, are orders of magnitude larger than the noise.

We have thousands of measurements of local-scale (100'd of m to few km) gravity variations that are corroborated by the measurement of the properties of materials beneath our feet. Universal acceleration does not account for these variations.

748

Flat Earth Investigations / Re: Please don't hit the dome. Astra

« on: September 14, 2020, 06:17:51 PM »

"That, I don't think was good."

Expert analysis!

749

Flat Earth Theory / Re: Gravity - measurement and applications

« on: September 13, 2020, 12:32:25 AM »

Tom you keep saying that gravimeters only measure seismic noise, even though the example that YOU dug up and spend the first half of this thread discussing demonstrated that the noise that is measured is 4 orders of magnitude less than the signal it was measuring.

You write them off as measuring nothing but noise, then give another example,the lacoste and bromberg set up, where they do exactly the thing you complained the first paper's authors DIDN'T do, but then write off the data because you dont understand the math they used... I'm at a loss.

UA doesnt account for the observed changes in pull measured by gravimeters when different masses are near, whether that's beneath earth's surface or directly above the instrument.

750

Flat Earth Theory / Re: Gravity - measurement and applications

« on: September 12, 2020, 01:26:20 PM »

For anyone else reading this, if you google laboratory calibration of gravimeter, you will find examples of measurements performed with a large mass suspended above a gravimeter, as Tom suggested, and there was a reduction in the observed 'pull' measured by the meter.

I would also point out that despite Tom's objections, the experimental measurements are exactly in line with the predictions of gravity. The experimental parameters also satisfied the researchers, the reviewers, and the journal associate editor.

If anyone wants to talk about the field measurements though, it's a really cool field of study and extremely useful in a wide range of investigations.

751

Flat Earth Theory / Re: Gravity - measurement and applications

« on: September 11, 2020, 09:46:37 PM »

I already conceded that you dont need to believe a gravimeter directly measures gravity. It measures the magnitude of downward pull experienced at a given location.

Collectively, the detection of changes in that measured pull, and the strong correlation between those changes and the physical properties of the rocks which underlie them, providence evidence that the measured pull results from differences in mass at different locations locally. Those point to gravity as the best possible explanation.

752

Flat Earth Theory / Re: Gravity - measurement and applications

« on: September 11, 2020, 09:13:35 PM »

Tom, this is just one single paper that you dug up. These types of tests and calibrations have been done thousands of times in hundreds of settings, on dozens of different instrumental designs.

I would reiterate that this method is part of billions of dollars in exploration studies around the world, which in turn lead to discovery of mineral bodies, oil and gas reservoirs, and help us identify and understand groundwater systems. The signals they measure provide only insight into what is happening in the subsurface. These are clues as to areas that need to be followed up with other types of geophysical and geological investigations in order to fully understand what is happening beneath our feet. The resounding evidence that changes in the gravitational strength observed at a given location result from the changing  properties of the materials.

I realize that I probably wont be able to change your mind on this issue. And that's OK.  I can only hope that others reading this will use the resources provided to decide for themselves.

753

Flat Earth Theory / Re: Gravity - measurement and applications

« on: September 11, 2020, 08:01:17 PM »

Paper from Canada:
nrcresearchpress.com/doi/pdfplus/10.1139/cjes-2016-0224

Others:
Gabriel et al. 2003 - geophysical investination of buried Pleistocene subglacial valleys in northern Germany

Moller et al 2007 - gravity field separation and mapping of buried quaternary valleys in Lolland Denmark. Journal of geo dynamics 43(2), 330-337.
The Scintrex operator manual from 1995 has some good examples of applications

754

Flat Earth Theory / Re: Gravity - measurement and applications

« on: September 11, 2020, 07:48:34 PM »

Yeah fair point!

Here's another example that is available free:

conservancy.umn.edu/bitstream/handle/11299/60798/1/mgs-264.pdf

755

Flat Earth Theory / Re: Electromagnetic Acceleration

« on: September 11, 2020, 06:32:20 PM »

Hi Pete, fair point on the DE response - I'll do some more digging around the wiki (but might also suggest that could be clarified on the EA page for future readers)

I'm still confused as to the statement of limitation of the equation to scenarios when y>>x. I'm asking specifically as EA is argued to provide the answer to why clouds are lit from the underside during sunrise and sunset, but the equation isnt valid for those times, where exactly does that leave things?

I should make it clear that I'm not trying to disprove the equation by any means, just understand how it is used to explain this commonly observed phenomenon.

756

Flat Earth Theory / Re: Electromagnetic Acceleration

« on: September 11, 2020, 04:20:27 PM »

To jump in on this, there are a few questions that came up from reading the wiki page on EA.

The article states that the equation provided for curvature only works when y (vertical distance of Ray's path) is much greater than x ( horizontal distance of Ray's path). If the sun is 3000 km up, how is this equation valid at sunset/sunrise, when the sun is at a horizontal distance of >6,000 km based on the models of night and day depicted on FE maps?

The other question relates to the inclusion of the Bishop constant, which relates to the magnitude of acceleration of a horizontal light ray induced by dark energy. How exactly does dark energy fit within a flat earth worldview when it was only discovered recently, though astronomical investigations, which are dismissed as pseudoscience in various articles within the wiki, and by the words of numerous FE proponents in various fora on this site.

757

Flat Earth Theory / Re: Gravity - measurement and applications

« on: September 11, 2020, 12:31:41 PM »

If there were active seismic waves (I.e. from a major event that causes notable vibrations of the the earth) passing by, we wouldn't be able to get our readings. As I mentioned earlier, the passing of large trucks forced us to pause because the vibrations made it impossible to take a reading.

We actually do multiple types of seismic investigations as well. Seismic reflection surveys involve a seismic source (vibrator or shockwave) and a series of receivers (think micro phones). As you said, different media transmits seismic waves differently (denser media transmit the waves the fastest, and the energy of the wave is both reflected and refracted at interfaces between layers of different properties. By measuring the time and amplitude of the seismic energy reflected back upward to the receivers, we essentially get a picture of the geometry and layering of different materials beneath the surface.

 In exploration contexts, the gravity survey will tell us whether there is a valley beneath your feet, the seismic survey will gives you clues as to what's actually in filling the valley, and then drilling will allow you to measure the properties, test the chemistry, measure permeability etc..

Gravimeters are absolutely able to detect ground vibrations from seismic waves. The problem is that gravimeters are so sensitive that they cant actually read them.

Since they both do they same thing- measure acceleration  they are similar instruments, but the nature of the accelerations they measure  (the enormous differences in their amplitudes and frequencies) requires them to be built very differently.  I would say you can think of them like boats. Depending on where you want to go, you would want a different type of boat. A 12-foot aluminum boat is great for getting you up and down a flat stretch of river, but I wouldn't want to be caught in one in the middle of a big lake on a windy day!

758

Flat Earth Theory / Re: Gravity - measurement and applications

« on: September 10, 2020, 12:14:14 PM »

To be fair, gravimeter measurements are noisy, and if you tried to take measurements during a seismic event, the additional accelerations would make it impossible. The instruments are so sensitive that we had a had time completing a survey along a busy road because any large trucks driving by created enough vibrations that we had to wait until they had passed.

But there are still large, pronounced responses that are observed in exploration surveys (whether that's for mineral deposits or groundwater incestigations) that we know with a very high degree of certainty are caused by varying properties of material beneath our feet, namely the different local distribution of mass.

 in the examples provided above, the noise level would be like repeatedly using one of those rolling distance measuring wheels to measure the distance around the curved part of a regulation Olympic sized track then plotting the difference in measurements you get in millimeters. You'll never get exactly 100 m, but you can get really close every time.

This just wasnt the discussion I wanted to have, but not that weve gone through the measurement and precision side of things, maybe we'll be able to move toward the issue at hand of the observed changes in force at different locations and at different times. I would argue that these data support the idea that the force is gravity and is problematic for a constant upward acceleration concept, but would happily consider other options to explain the phenomena that account for the observations

759

Flat Earth Theory / Re: Gravity - measurement and applications

« on: September 10, 2020, 02:35:24 AM »

Hey Tom, thanks for the continued input. Interesting study you linked about the gravimeter calibration and apparent drift.

I would point out the scale on the y axis, and that the 'typical noise' range is 20 nm/s2... converted into standard g values, that's 2.039x10^-9 g in noise.... that's a lot of significant figures to carry around.

The bouguer gravity anomalies that define buried valleys and mineral deposits are about three orders of magnitude stronger (lower value of~1.5 mGal from the paper I cited earlier).

Again I emphasize that the readings are then ground truthed in exploration studies, so we can then verify whether the observed differences in pull match with the density contrasts of the rock/sediment beneath.

760

Flat Earth Theory / Re: Gravity - measurement and applications

« on: September 09, 2020, 08:23:55 PM »

East-west profiles over short distances (1-3km) still register the local changes in gravimeter readings I'm talking about. This isnt just theory about density changes though. The subsurface properties are investigated by drilling and measurement of density/specific gravity etc.

You're 100% right that gravimeters dont measure gravity directly. They measure a pull on a mass.

BUT. Thousands of measurements spanning all the continents over many decades document changes in the pull over local scales. These are correlated with the observed properties of subsurface media (rocks, sediments, ice, water) in exploration settings, or with sun-moon positions, as you alluded to. Collectively, the local variations of the pull measured from all these gravimeters point to spatial and temporal variations in that pull. This collection of measurements and supporting ground truthing data is the evidence that gravity is the force exerting the pull, rather than a uniform upward acceleration.