The Flat Earth Society
Flat Earth Discussion Boards => Flat Earth Investigations => Topic started by: Tom Bishop on April 06, 2025, 10:00:22 PM
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I found a video of Brian Cox discussing the Flat Earth Society. He says that he doesn't believe in FE, but says that one of the things TFES got right is that the surface of the Earth is accelerating upwards. See this two minute segment from about 1:07:25 to 1:09:25:
https://youtu.be/zas--VfFdmk?si=0dh3DzfthsZ75JU8&t=4047
Brian Cox describes the idea of the Earth's surface accelerating upward as "bang on" and "actually right", and that in RE it is explained by spacetime curvature. What's particularly revealing is how Round Earth proponents must resort to abstract metaphysical concepts like "spacetime curvature" to explain what the Flat Earth model explains directly and intuitively.
I note that one thing that the Flat Earth has going for it is that it isn't perpetually exploding apart from itself. It is rising upwards, just as the experiments show. There are a plethora of Equivalence Principle experiments which directly suggest that the surface of the Earth is accelerating upwards. This doesn't work in RE, so space curvature is invoked. The Round Earth Theory weirdly explains the results of these experiments with metaphysics which invoke unseen mechanics from a hidden realm of existence. In RET the round earth is apparently exploding outwards, but this effect is oddly only manifested locally and in laboratory experiments.
Rather than acknowledging the upward acceleration of the earth's surface from direct experiment, mainstream science creates increasingly abstract mathematical models to preserve their spherical earth paradigm. When this topic has been discussed in the past, instead of RE proponents justifying their absurd theory with clear and direct evidence, we see indirect evidence and pivots to wanting to talk about why they think FE is wrong. This deflection reveals the fragility of their position when core assumptions are questioned. I strongly predict that the same will occur in this thread.
Cox's acknowledgment represents a rare moment of honesty from the scientific establishment about the validity of a central aspect of the Flat Earth Society's cosmology.
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Brian Cox appears to be enamored with the idea. During the same lecture on his history of gravity portion, Brian Cox explains that the earth is accelerating upwards:
https://twitter.com/ThatGuyM77/status/1763294353496137999
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Some explanation about what’s really going on here. Interesting stuff.
https://m.youtube.com/watch?v=OpOER8Eec2A
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That video actually goes through the evidence and affirms that the physical reality is that the surface of the earth is accelerating upwards. Upwards acceleration of the earth's surface doesn't work if the Earth is a ball, so unseen realms of existence are invented where mechanics are occurring beyond our perception. All of the curved space metaphysics are an effort to explain the results of laboratory experiments which say that the surface is accelerating, upwards under a round earth mindset.
The reason why we always just see Brian Cox or others merely explaining what it is, but we never see direct defense of the upward acceleration of the earth's surface through space time, is because it is ridiculous beyond words and practically indefensible. These unseen realms exist because they must exist. The wider proofs for relativity, such as the relativity solar system fix to the retrograde motion of Mercury, are hardly sufficient to tell us that the surface of the earth is accelerating upwards in an unseen realm, and the Mercury proof has been alleged to be tweaked to get that result.
This issue with gravity is enough on its own to settle the matter for me and overshadows everything else. If you believe in the truth to the motion of bodies, then you must believe in Flat Earth. If you are willing to believe in weird metaphysics in unseen realms where things can appear to be moving but are not moving, then you can believe in the Round Earth. Any other topic diversions and wuddabouts will leave open the issue that there is practically no evidence for the absurd notion that the earth's surface is accelerating upwards through space time. We are expected to believe in an absurdity to the concept of motion, on blind faith alone.
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That video actually goes through the evidence and affirms that the physical reality is that the surface of the earth is accelerating upwards.
lol. He literally doesn’t use the word physical or physically once. He explains quite well how the acceleration is not physical.
Upwards acceleration of the earth's surface doesn't work if the Earth is a ball, so unseen realms of existence are invented where mechanics are occurring beyond our perception.
Also not true. He also explains how this explains gravitational red shift and time dilation. Both of these things have been verified experimentally and he mentions how time dilation is taken in to account in GPS satellites. This isn’t blind faith, these are predictions of Einstein’s theories and have been observed to be true.
The reason why we always just see Brian Cox or others merely explaining what it is, but we never see direct defense of the upward acceleration of the earth's surface through space time, is because it is ridiculous beyond words
As a wise man once said (see my sig)
“Claiming incredulity is a pretty bad argument. Calling it "insane" or "ridiculous" is not a good argument at all."
:)
You continue to conflate “I don’t understand this” with “this is not possible”. And curiously you do so while cherry picking parts of mainstream science where it suits your agenda. There’s no crime in being ignorant, but it’s a little silly to base a whole worldview on that ignorance.
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That video actually goes through the evidence and affirms that the physical reality is that the surface of the earth is accelerating upwards.
lol. He literally doesn’t use the word physical or physically once. He explains quite well how the acceleration is not physical.
Actually, he does say that the upwards acceleration manifests as physical phenomena. At around the 5:50 mark he explains:
this means when the light travels
up its frequency reduces and in light
when the frequency reduces it goes
towards red end of the Spectrum in other
words we get a red shift due to gravity
this is something that Newton did not
predict so if Einstein is indeed right
we should see gravitational red shift
and we saw it you can Google pound rebka
experiment for more details
Light shifts red, indicating that the ceiling of the building is accelerating away. The Newtonian theory of bodies falling "down" does not predict this. It is using the same mechanism of a policeman's radar gun which uses the red or blue shift of light to determine acceleration. When cars are accelerating away from the policeman, the light redshifts. In this experiment the doppler shift is coined as "gravitational redshift", and in the opposite direction towards the ground light blueshifts as the earth accelerates into it, all expected physical effects on an upwardly accelerating surface. This is one of many experiments which tells us that the earth is accelerating upwards.
Direct experiments on the earth's surface tell us that the earth is accelerating upwards. Bending space and physics in unseen dimensions are used to explain this as an illusion of a metaphysical realm where the earth is not exploding apart from itself. The evidence itself of the surface's upward acceleration is undeniable as far as experimentation is concerned, and "bending space" is the resulting cope mechanism.
Upwards acceleration of the earth's surface doesn't work if the Earth is a ball, so unseen realms of existence are invented where mechanics are occurring beyond our perception.
Also not true.
Have you seen the earth's surface accelerating upwards through bending space? If not, then it is unseen. You are talking about unseen physics in unseen realms, which is nonsense to say the least.
The reason why we always just see Brian Cox or others merely explaining what it is, but we never see direct defense of the upward acceleration of the earth's surface through space time, is because it is ridiculous beyond words
As a wise man once said (see my sig)
“Claiming incredulity is a pretty bad argument. Calling it "insane" or "ridiculous" is not a good argument at all."
That's not the only part of the argument. The other part is that there is a lack of evidence that the earth's surface is accelerating upwards through space time or bending space.
You continue to conflate “I don’t understand this” with “this is not possible”. And curiously you do so while cherry picking parts of mainstream science where it suits your agenda. There’s no crime in being ignorant, but it’s a little silly to base a whole worldview on that ignorance.
Actually this thread shows that mainstream science is cherry picking what to accept. It can't accept an upwardly accelerating earth, so here you are mumbling on their behalf about alternate dimensions that you can't show us.
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Direct experiments on the earth's surface tell us that the earth is accelerating upwards.
The OP and the relevant wiki articles all frequently and approvingly refer to the Equivalence Principle when discussing UA, but the EP states that acceleration of the Earth and gravitational acceleration are experimentally indistinguishable. How then can experiments on the Earth’s surface tell us that it’s the Earth physically accelerating upwards, not gravity pulling us towards Earth?
The OP has some explaining to do before rubbishing general relativity.
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Actually, he does say that the upwards acceleration manifests as physical phenomena. At around the 5:50 mark he explains
I won't bother re-quoting the part you quoted in which he doesn't say it's a physical phenomenon at all.
He very carefully explains that it's the time dilation which causes the shift. Nothing physical at all. With the cones he explains how the ground can be accelerating upwards on different sides of the earth without the earth expanding. Not sure why you are ignoring that.
The cherry picked quote doesn't even say what you claim.
It is using the same mechanism of a policeman's radar gun which uses the red or blue shift of light to determine acceleration. When cars are accelerating away from the policeman, the light redshifts.
You think the cars have to be accelerating for them to work? That would be very inefficient, they'd never catch anyone speeding who is going at a constant speed. They do work by Doppler shift, usually of radar not visible light. Some use lasers and they also use the time taken for the signal to return to the device.
That's not the only part of the argument. The other part is that there is a lack of evidence that the earth's surface is accelerating upwards through space time or bending space.
The evidence is the observations and experiments. Einstein's theory of gravity predicts these things, Newton's doesn't. Multiple experiments have been done which observe the things Einstein predicted. That's how we know that Einstein's model of gravity is better than Newton's. Although Newton's works fine in most circumstances. As I said, GPS satellites take Relativistic effects into account in order for it to work accurately
https://www.gpsworld.com/inside-the-box-gps-and-relativity/
Actually this thread shows that mainstream science is cherry picking what to accept. It can't accept an upwardly accelerating earth
Another one of your "no u" arguments.
You literally started this thread by citing Brian Cox explaining how earth is accelerating upwards. My video also says that, but it also explains that it is not a physical acceleration - again, the cone thing. It's an acceleration through spacetime. The weird thing is on this Wiki page you use Relativity to explain why UA doesn't accelerate the earth beyond the speed of light:
https://wiki.tfes.org/Universal_Acceleration#Accelerating_to_the_Speed_of_Light
This is another example of your cherry picking. You use Relativity to explain things when it suits you, you dismiss it as some magical mystical thing which can't be true when it doesn't suit you.
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Direct experiments on the earth's surface tell us that the earth is accelerating upwards.
The OP and the relevant wiki articles all frequently and approvingly refer to the Equivalence Principle when discussing UA, but the EP states that acceleration of the Earth and gravitational acceleration are experimentally indistinguishable. How then can experiments on the Earth’s surface tell us that it’s the Earth physically accelerating upwards, not gravity pulling us towards Earth?
The OP has some explaining to do before rubbishing general relativity.
The problem is that you read a sentence about gravity from physicists and think that it's talking about Newtonian Gravity because that is the topic in dispute here. Those the same physicists also say that General Relativity succeeded Newtonian Gravity long ago. The gravity they are talking about is General Relativity. They are saying that upwards acceleration of the earth's surface and the General Relativity theory of gravity are experimentally indistinguishable in laboratory experiments. You will also find that those sentences of indistinguishability appear in articles about the history and advantages of Einsteinian gravity, giving additional context to which gravity it is talking about.
Newtonian Gravity where things fall "down" has a litany of problems, such as not predicting the redshifting of light when pointed at a ceiling, as mentioned above.
Another problem is that Newtonian Gravity actually predicts that objects with twice the mass will fall twice as fast, and this fixed with ad-hoc bandaid mechanisms. A Space.com article Relativity: The Thought Experiments Behind Einstein's Theory (https://www.space.com/40920-relativity-power-of-equivalence.html) by astrophysicist Paul Sutter explains that under a plain interpretation of how Newtonian Gravity pulls on objects, a body with twice the mass of another should fall faster. Newtonian Gravity requires a separation of inertial and gravitational mass and their equivalence for bodies to fall equally. It is suggested in this article that this is an ad-hoc mechanism to explain physical phenomena.
“ Einstein's first insight into the nature of gravity was to put a new twist on an old idea. In Isaac Newton's original mathematical description of gravity ("OG"?), there's an odd coincidence when it comes to the concept of "mass." In one famous equation, F = ma, mass is your inertia — how much oomph it takes to shove you along. In Newton's other equation on gravity, mass is more like gravitational charge — the level of attraction you might feel toward the Earth, for example.
Objects with twice the mass feel twice the attraction toward the Earth, and should therefore fall twice as quickly. But years back, Galileo Galilei had conclusively shown that they don't: Neglecting air resistance, all objects fall at the same rate regardless of their mass.
Thus for Newton's theory to work, inertial mass had to be the same as gravitational mass, but only by sheer coincidence: there was no reason for this equality to hold. For an object with twice the mass, the Earth may pull on it twice as strongly, but this is perfectly canceled out by the fact that it's now twice as hard to get the object moving. Inertial and gravitational masses move in perfect lockstep.
This odd correspondence had long been a puzzle in gravitational circles, but in 1907, Einstein took it one step further. The physicist imagined what would happen if you were to fall from a great height. Again neglecting air resistance, your inertial and gravitational masses would cancel, making you feel perfectly weightless, as if there were no gravity at all. But zero-gravity environments are precisely the playground of Special Relativity, the theory he had cooked up just a couple years prior that wove our conceptions of space and time into the unified fabric of spacetime.
To Einstein, this was a major clue. Lurking in the shadows of gravity was his precious special relativity and the essential concept of space-time, and what made that realization possible was the elevation of the equivalence between inertial and gravitational masses into a fundamental principle, rather than the awkward afterthought it had been. ”
As mentioned above, it is a sheer coincidence that they are equal. For example, if the gravity field of the earth were stronger it would increase the 'gravitational mass' of the object. It would no longer match the inertial resistance of an object. It is incredible that the earth is a special planet where the gravity field exactly matches what is necessary to cause this weightless effect.
This weightless effect where bodies of differing masses fall together is so absurd that Einstein recognized it for what it is, the upwards acceleration of the Earth's surface. In another video about bodies which fall together (https://www.youtube.com/watch?v=E43-CfukEgs&feature=youtu.be&t=3m53s), Brian Cox explains:
"The reason, why the bowling ball and the feather, fall together is because they are not falling! They are standing still! There is no force acting on them at all! He (Einstein) reasoned, that if you couldn't see the background, the'd be no way of knowing, that the ball and and the feathers are being accelerated towards the Earth - so he concluded ... they weren't"
Brian Cox seems to be in love with this idea of the earth accelerating upwards, that he can't help but bring it up again and again and again, throwing this absurdity in our face and celebrating how weird physics is that it is this way.
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It appears that one should be wary of which YouTube physicist's explanation you should believe. It seems that space-time diagrams showing curvature have been mistaken for space-time curvature causing some confusion as to the actual cause of gravity.
https://www.youtube.com/watch?v=PjT85AxTmI0
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Direct experiments on the earth's surface tell us that the earth is accelerating upwards.
The OP and the relevant wiki articles all frequently and approvingly refer to the Equivalence Principle when discussing UA, but the EP states that acceleration of the Earth and gravitational acceleration are experimentally indistinguishable. How then can experiments on the Earth’s surface tell us that it’s the Earth physically accelerating upwards, not gravity pulling us towards Earth?
The OP has some explaining to do before rubbishing general relativity.
The problem is that you read a sentence about gravity from physicists and think that it's talking about Newtonian Gravity because that is the topic in dispute here. Those the same physicists also say that General Relativity succeeded Newtonian Gravity long ago. The gravity they are talking about is General Relativity. They are saying that upwards acceleration of the earth's surface and the General Relativity theory of gravity are experimentally indistinguishable in laboratory experiments. You will also find that those sentences of indistinguishability appear in articles about the history and advantages of Einsteinian gravity, giving additional context to which gravity it is talking about.
Remarkable. I'll be blunt then, which experiments on Earth's surface tell us it's the Earth physically accelerating upwards, not gravity pulling us towards Earth?
Your difficulties with Brian Cox are at least partly accounted for by his mischievous nature – in the original video you referenced, he's already mocked people calling him a paid NASA shill by claiming that's how he can afford to stay in the Raffles Hotel, Singapore, lol. General Relativity builds on the work of Special Relativity by developing a means of relating different frames of reference where acceleration and/or rotation are involved. The mathematical methods of accomplishing this are indeed very high-level, but they allow us to consider a reference frame with the Earth moving upwards through space if that suits the case we want to analyse. Cox and others enjoy provoking the viewer's interest by citing just such a case, as well as having a dig at those who believe the Earth is physically accelerating upwards. Protesting about "metaphysical mathematics" only shows no appreciation of the breadth and scope of the subject – it's beyond my pay grade too, but you might at least try. On the other hand, UA is easily dismantled with some experimental evidence and schoolboy physics.
Should anyone's interest be piqued, Einstein himself wrote a more accessible book on both SR and GR. https://www.ibiblio.org/ebooks/Einstein/Einstein_Relativity.pdf (https://www.ibiblio.org/ebooks/Einstein/Einstein_Relativity.pdf)
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Remarkable. I'll be blunt then, which experiments on Earth's surface tell us it's the Earth physically accelerating upwards, not gravity pulling us towards Earth?
It's mostly all the stuff you have already heard about.
- Light redshifts when pointed at a ceiling. This is predicted by the earth's upward acceleration, as the ceiling accelerates away from the light. It is not predicted by Newtonian Gravity.
- The perceived information from a clock speeds up as the clock increases in height above you. This is predicted by the upward acceleration of a surface (https://wiki.tfes.org/Gravitational_Time_Dilation#Description), where the observer is accelerating into the broadcasted photons. It is not predicted by Newtonian Gravity.
- Bodies and particles of different masses fall together, despite that they have different inertial resistances and require different amounts of energy to be moved. This is predicted by an upwards accelerating earth, and requires an absurd coincidence in Newtonian Gravity, as described by the above space.com article.
- Bodies are weightless as they fall. A strand of hair or globule of water will have different parts of its atoms moving up and down weightlessly, when a downward pulling gravity should be pulling all atoms "down" together. If a flat falling rope or strand of hair is falling, pulled downwards at every atom, even at the same rate, it should not freely flex and bunch in every direction and deform as if in a weightless environment. In loosely connected matter such as water, a hair, or a rope, there should be resistance against the downwards pulling gravity if some atoms try to go upwards in relation to the rest.
The reason these phenomena are being pointed out with interest by physicists in the relativity articles is because it's not something Newtonian Gravity adequately predicts. The weightless absurdity is Einstein's "Happiest Thought", which led him to his Equivalence Principle. Why would he be so happy if it was something that was adequately explained for centuries? These phenomena are pointed out as wow amazing in the introduction to relativity texts because they go against intuition of a world where things are being pulled downwards, instead suggesting that the surface is being pushed upwards. If Newtonian Gravity predicted everything fine there would be no reason to replace it.
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Your difficulties with Brian Cox are at least partly accounted for by his mischievous nature – in the original video you referenced, he's already mocked people calling him a paid NASA shill by claiming that's how he can afford to stay in the Raffles Hotel, Singapore, lol.
It's not only Brian Cox saying this, see these collected quotes from https://wiki.tfes.org/Equivalence_Principle
Gravity: A Very Short Introduction
From Gravity: A Very Short Introduction (https://books.google.com/books?id=FFQjDgAAQBAJ&pg=PT34&lpg=PT34&dq=%22earth+pushing+you%22&source=bl&ots=MV9ROmx5Eu&sig=ACfU3U17gR2YnIJbxFhEuRhKz2cR-mVBgQ&hl=en&sa=X&ved=2ahUKEwjaoLf6xMHiAhUPpFkKHTqqAMwQ6AEwDXoECB0QAQ#v=onepage&q=%22earth%20pushing%20you%22&f=false) by Cosmologist Timothy Clifton, we read:
“ Consider a skydiver jumping out of an airplane. The skydiver falls freely, up to the effects of air resistance. According to Einstein, the skydiver's path is the straightest line possible through the curved space-time around the Earth. From the skydiver's perspective this seems quite natural. Except for the air rushing past her, the skydiver feels no perturbing forces at all. In fact, if it weren't for the air resistance, she would experience weightlessness in the same way that an astronaut does in orbit. The only reason we think the skydiver is accelerating is because we are used to using the surface of the Earth as our frame of reference. If we free ourselves from this convention, then we have no reason to think the skydiver is accelerating at all.
Now consider yourself on the ground, looking up at the falling daredevil. Normally, your intuitive description of your own motion would be that you are stationary. But again this is only because of our slavish regard to the Earth as the arbiter of what is at rest and what is moving. Free yourself from this prison, and you realize that you are, in fact, accelerating. You feel a force on the soles of your feet that pushes you upwards, in the same way that you would if you were in a lift that accelerated upwards very quickly. In Einstein's picture there is no difference between your experience sanding on Earth and your experience in the lift. In both situations you are accelerating upwards. In the latter situation it is the lift that is responsible for your acceleration. In the former, it is the fact that the Earth is solid that pushes you upwards through space-time, knocking you off your free-fall trajectory. That the surface of the Earth can accelerate upwards at every point on its surface, and remain as a solid object, is because it exists in a curved space-time and not in a flat space.
With this change in perspective the true nature of gravity becomes apparent. The free falling skydiver is brought to Earth because the space-time through which she falls is curved. It is not an external force that tugs her downwards, but her own natural motion through a curved space. On the other hand, as a person standing on the ground, the pressure you feel on the soles of your feet is due to the rigidity of the Earth pushing you upwards. Again, there is no external force pulling you to Earth. It is only the electrostatic forces in the rocks below your feet that keep the ground rigid, and that prevents you from taking what would be your natural motion (which would also be free fall).
So, if we free ourselves from defining our motion with respect to the surface of the Earth we realize that the skydiver is not accelerating, while the person who stands on the surface of the Earth is accelerating. Just the opposite of what we usually think. Going back to Galileo's experiment on the leaning tower of Pisa, we can now see why he observed all of his cannonballs to fall at the same rate. It wasn't really the cannonballs that were accelerating away from Galileo at all, it was Galileo that was accelerating away from the cannonballs! ”
Why Is Spacetime Curved?
In a section titled Why Is Spacetime Curved? (https://books.google.com/books?id=3QBgCgAAQBAJ&newbks=1&newbks_redir=0&lpg=PP1&pg=PT97#v=onepage&q&f=false) of the book Time Travel in Einstein’s Universe by John Richard Gott III, professor of astrophysical sciences at Princeton University, we read:
“ A famous (perhaps apocryphal) story about Einstein describes one occasion when he fell into conversation with a man at the Institute for Advanced Study at Princeton. During their chat, the man suddenly pulled a little book from his coat pocket and jotted something down. Einstein asked, “What is that?" “Oh,” the man answered, “it's a notebook I keep, so that any time I have a good idea I can write it down before I forget it.” “I never needed one of those," Einstein replied. “I only had three good ideas.”
One of them occurred to him in 1907—what he would later call the “happiest” idea of his life. Einstein noted that an observer on Earth and an observer on an accelerating spaceship in interstellar space would have the same sensations. Follow this chain of thought to see why. Galileo had shown that an observer dropping two balls of different mass on Earth sees them hit the floor at the same time. If an observer in an accelerating rocket in interstellar space performed the same experiment, dropping two balls of different mass, they would float motionless in space—but, since the rocket was firing, the floor of the spaceship would simply come up and hit both of them at once. Both observers thus should see the same thing. In one case, it is the result of gravity; in the other case, it is caused by an accelerating floor with no gravity involved. But then Einstein proposed something very bold—if the two situations looked the same, they must be the same. Gravity was nothing more than an accelerated frame-of-reference. Likewise, Einstein noted that if you get in an elevator on Earth and cut the cable, you and everything in the elevator will fall toward Earth at the same rate. (Galileo again—objects of different mass all fall at the same rate.) So, how do things look to you in the falling elevator? Any object you drop will float weightless in the elevator—because you, the object, and the elevator are all falling at the same rate together. This is exactly what you would see if you were in a spaceship floating in interstellar space. All the objects in the spaceship, including you, would be weightless. If you want to experience weightlessness just like an astronaut, all you have to do is get in an elevator and cut the cable. (This works, of course, only until the elevator hits bottom.)
Einstein's assertion that gravity and acceleration are, the same—which he called the equivalence principle—was influenced, no doubt, by his previous success in equating the situation of a stationary magnet and a moving charge with that of a stationary charge and a moving magnet. But if gravity and accelerated motion were the same, then gravity was nothing but accelerated motion. Earth's surface was simply accelerating upward. This explained why a heavy ball and a light ball, when dropped, hit the floor at the same time. When the balls are released, they just float there—weightless. The floor (Earth) simply comes up and hits them. What a remarkably fresh way of looking at things!
Still one must ask how Earth’s surface could be accelerating upward (away from Earth's center) if Earth itself is not getting bigger and bigger with time like a balloon. The only way the assertion could make sense is by considering spacetime to be curved.
Einstein proposed that mass and energy cause spacetime to curve. It took him 8 years of hard work to derive the equations governing this. He had to learn the abstruse geometry of curved higher dimensional spaces. He had to learn about the Riemannian curvature tensor—a mathematical monster with 256 components telling how spacetime could be curved. This was very difficult mathematics, and Einstein ran upon many false leads. But he didn't give up because he had great faith in the idea. ”
Relativity Visualized
“ Einstein’s view of gravity is that things don’t fall; the floor comes up! ”
—Epstein, Lewis Carroll: Relativity Visualized. (Insight Press, San Francisco, 1988) pp. 65 ff.
Tony Goldsmith
Tony Goldsmith, author of a mass-media book Space-time for Absolute Beginners and his Absolute Beginner book series, explains the Equivalence Principle as follows (https://www.quora.com/General-relativity-says-when-I-am-standing-on-the-surface-of-the-Earth-I-am-being-accelerated-by-gravity-How-can-I-be-accelerating-if-the-Earth-is-in-the-way-preventing-my-movement-Is-this-acceleration-different/answer/Tony-Goldsmith-6?ch=10&oid=96428363&share=98a2ceb5&srid=hiF1m&target_type=answer):
“ When you are in a lift you may be accelerated. Where is this coming from? It is the lift pushing you up.
Einstein said that the Earth does the same as a lift (which has an acceleration of g). The Earth isn't in the way; it is doing the pushing. This is his Equivalence Principle. ”
Why Gravity is NOT a Force
A popular science video by Veritasium with over 10 million views, Why Gravity is NOT a Force, explains at the 9:57 mark how in General Relativity you accelerate upwards without changing your spatial coordinates (https://youtu.be/XRr1kaXKBsU?t=597) with the General Relativity equation:
“ But if I'm accelerating up and so is everyone else around the world and presumably the whole surface of the Earth, then shouldn't the whole earth be expanding?
No. It is possible for you to be accelerating even though your spatial coordinates are not changing. I will show you one equation from General Relativity...
(equation)
...so in curved space-time you have to accelerate just to stand still. ”
Inner Life of Numbers
In a book on how math relates to the universe One to Nine: The Inner Life of Numbers by mathematician Andrew Hodges, he describes that the earth's surface is accelerating upwards against your feet in the geometry of curved space-time (https://books.google.com/books?id=UCuwrtBax7AC&newbks=1&newbks_redir=0&lpg=PP1&pg=PA138#v=onepage&q&f=false):
“ Earth's mass curves the geometry of space-time in such a way that the Earth's surface is always accelerating upwards at 9.81 m/sec^2 and so presses on your feet. Weight doesn't exist, but the Earth's electromagnetic forces push harder on fat boys than on slim. This sounds crazy, but it is no crazier than the fact that if you steam straight ahead on a sphere you will end up back where you started. Such things are made possible by curvature. ”
Earth’s Surface Accelerates Up (and Out)
A physics student, Berry, came across this subject and made us a brief paper about what he learned in his upper level physics classes, showing the math on how in the globe model of gravity the surface of the earth is actually accelerating upwards (https://www.docdroid.net/AbDLJgt/earths-surface-accelerates-upwards-pdf).
“ This paper uses the Schwarzchild geometry utilized by the current globe Earth model to show that the surface of the Earth is accelerating upwards. ”
The video Markjo posted above also has the earth accelerating upwards at the twelve minute mark:
(https://i.imgur.com/eanFbje.png)
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Remarkable. I'll be blunt then, which experiments on Earth's surface tell us it's the Earth physically accelerating upwards, not gravity pulling us towards Earth?
It's mostly all the stuff you have already heard about.
- Light redshifts when pointed at a ceiling. ...
- The perceived information from a clock speeds up as the clock increases in height above you....
- Bodies and particles of different masses fall together...
- Bodies are weightless as they fall...
The reason these phenomena are being pointed out with interest by physicists in the relativity articles is because it's not something Newtonian Gravity adequately predicts.
You are assuming I have objections to General Relativity as an explanation of gravity – incorrect, I have no particular difficulties with it, despite the mathematical challenges. However, none of the phenomena you have listed, or the many others referenced in the wiki, demonstrate that Earth is physically accelerating upwards. This is entirely consistent with the Equivalence Principle, that a person standing inside a closed box on Earth would be unable to distinguish his circumstances from being instead in a box in empty space being accelerated at 9.8ms-2. You seem to think GR means a flat earth is forever physically accelerating upwards, but GR doesn't make that claim. It instead says that with a suitable reference frame, Earth can be considered as accelerating towards the apple. It's the same story Einstein repeatedly uses, that of the passenger on the train versus the observer on the railway embankment: to the passenger, the embankment can be regarded as moving relative to the train. He nowhere says the embankment must be moving and the train at rest.
If we confine the application of the theory to the case where the gravitational fields can be regarded as being weak, and in which all masses move with respect to the co-ordinate system with velocities which are small compared with the velocity of light, we then obtain as a first approximation the Newtonian theory. Albert Einstein
You'll find that quotation in the book I referred to above. Should you know of an experiment which clearly indicates Earth is physically accelerating upwards, I'd be delighted to hear of it.
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That was your third post in this thread you have already abandoned Newtonian Gravity and the idea that objects fall "downwards." What will you abandon in another three posts? Will it be the insistence on unseen dimensions, metaphysical curvature, or perhaps the reliance on abstract mathematics that only serves to obscure the reality of the Earth's upward acceleration?
Things do not "fall" to the ground. The so-called "falling" is nothing more than the result of the Earth accelerating upwards at 9.8 m/s², as evidenced by direct observations and experiments. The fact that reality is this way shows that the earth is flat, not that we must create abstract explanations to explain it. The flat earth model simply accepts what the evidence directly shows without requiring extra mathematical dimensions or "curvature" that nobody can see. Your theory of gravity, however, attempts to explain these phenomena by resorting to an interdimensional simulation of upward acceleration through curved spacetime. This is not only convoluted but also entirely unnecessary. Inventing bizarre physics to fit a Round Earth paradigm is the wrong approach.
The evidence overwhelmingly supports the upwards acceleration of the surface as the more direct explanation of physical reality. The upwards acceleration of a flat surface does not require the metaphysical gymnastics of curved spacetime or the invention of unseen realms. The earth is not continually exploding apart from itself interdimensionally in a desperate explanation of reality. It relies on observable phenomena and empirical data, while your Round Earth model continually retreats into abstraction whenever its foundational assumptions are questioned.
You seem to think GR means a flat earth is forever physically accelerating upwards, but GR doesn't make that claim. It instead says that with a suitable reference frame, Earth can be considered as accelerating towards the apple.
The experiments show that there is clear physical evidence supporting the idea that the Earth is accelerating upwards. Yet you dismiss this as merely mathematical, claiming we can "consider" the Earth as accelerating upwards without it being physically real. This is outright denial of physical evidence and a refusal to engage with reality.
Let’s examine your position. How can the surface of the Earth be "accelerating upwards" in some unseen mathematical dimension while its physical effects, such as redshifts, time dilation, and weightlessness in free fall, are undeniably real and observable? If the effects are real and measurable, then why isn’t the mechanical process of upward acceleration also real?
Your response reveals the lengths to which defenders of this absurd theory must go to justify their position. By retreating into abstract, unseen models and redefining physical phenomena as "considerations," you sidestep the evidence at hand. This isn’t an argument grounded in science, it's an exercise in creating convoluted explanations to prop up an outdated paradigm.
When pressed to defend your position, you resort to nonsensical jargon and metaphysical abstractions, which only highlight the weaknesses in your argument. The most direct explanation, supported by experimentation and direct observation, is that the Earth is physically accelerating upwards; no unseen dimensions or "considerations" required.
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Things do not "fall" to the ground. The so-called "falling" is nothing more than the result of the Earth accelerating upwards at 9.8 m/s², as evidenced by direct observations and experiments.
Then why do your cherry-picked quotes not say that then. Literally the first one you quote says:
In both situations you are accelerating upwards. In the latter situation it is the lift that is responsible for your acceleration. In the former, it is the fact that the Earth is solid that pushes you upwards through space-time
And:
That the surface of the Earth can accelerate upwards at every point on its surface, and remain as a solid object, is because it exists in a curved space-time and not in a flat space.
Once again you've quoted something which doesn't even say what you're trying to pretend it says.
And in your model why doesn't the acceleration mean the earth is now going faster than the speed of light? Don't worry, bro, special relativity has you covered:
https://wiki.tfes.org/Universal_Acceleration#Why_doesn.27t_the_Earth.27s_velocity_reach_the_speed_of_light.3F
Cherry picking again. You dismiss Special Relativity as some "abstract explanation" when it suits you, you accept and use it to explain other things when it suits you.
It's so intellectually dishonest. And once again you conflate "I don't understand this" with "this can't be true". The rest of your post is a box set of your arguments from incredulity. As a "wise" man once said:
Claiming incredulity is a pretty bad argument
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Inventing bizarre physics to fit a Round Earth paradigm is the wrong approach.
This statement from someone who postulates Electromagnetic Acceleration and even has a mathematical, as yet, undefined constant named for him is beyond comical.
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Inventing bizarre physics to fit a Round Earth paradigm is the wrong approach.
This statement from someone who postulates Electromagnetic Acceleration and even has a mathematical, as yet, undefined constant named for him is beyond comical.
I'm curious about the bizarre physics that would be needed to uniformly accelerate the flat earth and all of the celestial objects.
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Things do not "fall" to the ground. The so-called "falling" is nothing more than the result of the Earth accelerating upwards at 9.8 m/s², as evidenced by direct observations and experiments.
Then why do your cherry-picked quotes not say that then. Literally the first one you quote says:
In both situations you are accelerating upwards. In the latter situation it is the lift that is responsible for your acceleration. In the former, it is the fact that the Earth is solid that pushes you upwards through space-time
And:
That the surface of the Earth can accelerate upwards at every point on its surface, and remain as a solid object, is because it exists in a curved space-time and not in a flat space.
Once again you've quoted something which doesn't even say what you're trying to pretend it says.
The quotes I provided support the understanding that the surface of the Earth exhibits effects consistent with upward acceleration. While you continue to come up with an argument in favor of "space-time," the observable phenomena, gravitational redshift, time dilation, and weightlessness, are consistent with upward motion. The distinction between "mechanical" upward acceleration and the "space-time curvature" explanation hinges on interpretation, but the physical effects remain identical. My interpretation is based on direct observations rather than metaphysical constructs.
And in your model why doesn't the acceleration mean the earth is now going faster than the speed of light? Don't worry, bro, special relativity has you covered:
https://wiki.tfes.org/Universal_Acceleration#Why_doesn.27t_the_Earth.27s_velocity_reach_the_speed_of_light.3F
Cherry picking again. You dismiss Special Relativity as some "abstract explanation" when it suits you, you accept and use it to explain other things when it suits you.
Actually that section is addressing a believer in SR who believes that there is a speed of light limit. They are incorrect about what SR says. Special Relativity's limit on the speed of light is well-understood, and the explanation provided in the TFES Wiki shows why constant acceleration does not violate this principle. The velocity asymptotically approaches the speed of light due to relativistic effects, meaning it never exceeds it.
Your accusation of cherry-picking is unfounded. Whether Special Relativity is real, or whether it is entirely false and there is no light speed limit, what matters is that the observed phenomena for gravity align with upward acceleration.
It's so intellectually dishonest. And once again you conflate "I don't understand this" with "this can't be true". The rest of your post is a box set of your arguments from incredulity.
The argument is not based on incredulity but on the simplicity and directness of the evidence. The Flat Earth model accepts the observed upward acceleration without invoking unseen dimensions or speculative theories like space-time curvature. The incredulity lies in the need for such convoluted frameworks when the phenomena can be explained more intuitively.
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The flat Earth model accepts the observed upward acceleration without invoking unseen dimensions or speculative theories like space-time curvature. The incredulity lies in the need for such convoluted frameworks when the phenomena can be explained more intuitively.
What non-speculative theory explains how upward acceleration stops the second one steps off the earth until such a time that an object has acquired enough distance from the earth to cause it to accelerate upward at the same rate?
And, while you're at it, please explain what non-speculative theory explains the force causing this upward acceleration.
Then you can tell us what non-speculative theory explains why sunlight travels different distances across the surface of the flat earth.
I guess I already mentioned above that wonderful non-speculative theory that is EA.
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This statement from someone who postulates Electromagnetic Acceleration and even has a mathematical, as yet, undefined constant named for him is beyond comical.
Your response perfectly illustrates the deflection tactic I predicted at the outset of this thread. Instead of addressing the core argument, you attempt to dismiss the discussion by referencing unrelated topics. This does nothing to defend your position that the Earth is continually exploding apart from itself through speculative mechanisms like space-time curvature.
Instead of providing evidence or a coherent defense of the Round Earth model's reliance on metaphysical constructs like curved space-time, you attempt to derail the discussion by mocking unrelated ideas. This is a textbook example of an ad hominem fallacy. If you believe the Round Earth explanation of gravity is superior, demonstrate it with evidence and logical reasoning, not deflection.
You have provided no evidence or logical argument to support the claim that the Earth is accelerating upward through curved space-time. Instead, you resort to dismissive remarks. This lack of engagement suggests that even you recognize the intractability of the Round Earth explanation, which requires increasingly convoluted abstractions to justify its claims. If the Round Earth model were as robust as you imply, why not defend it directly?
I'm curious about the bizarre physics that would be needed to uniformly accelerate the flat earth and all of the celestial objects.
You should probably first focus on the problem with the official model that the earth is exploding apart from itself in an unseen dimension, and that the surface of the earth is accelerating upwards through spacetime. Where is the evidence for this? Your reference texts give the acceleration phenomena proofs that the earth is accelerating upwards as proof enough that this is happening, which is insufficient considering that there is another more direct interpretation.
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a mathematical, as yet, undefined constant
It will be so funny when the penny finally drops. It'll be your new "unknown unknowns" moment. It's so, so incredibly mind-boggling that you've been saying this for years and didn't think to check yourself even once.
named for him is beyond comical.
What the fuck do you want Tom to do about the fact that someone named a variable after him? How does this even begin to be relevant?
Also, to be abundantly clear, and to make sure you definitely understand what I'm saying here: if you don't know how to post in the upper, do not post in the upper. I get it - you don't like the subject (it's in your username), and you don't know how to handle things you don't like (it's in your username). But you're in the wrong place for this.
If you want to argue for RE, you're welcome to, but this sort of shit-stirring from you ends now. Super-duper final warning, for realsies.
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I'm curious about the bizarre physics that would be needed to uniformly accelerate the flat earth and all of the celestial objects.
You should probably first focus on the problem with the official model that the earth is exploding apart from itself in an unseen dimension, and that the surface of the earth is accelerating upwards through spacetime.
Einstein already figured that out. That you don't understand it isn't surprising, a lot RE physicists have trouble understanding it too. It's been said that if you think you understand relativity, then you don't understand relativity.
Where is the evidence for this? Your reference texts give the acceleration phenomena proofs that the earth is accelerating upwards as proof enough that this is happening, which is insufficient considering that there is another more direct interpretation.
GR is one of the most thoroughly tested theories ever, starting with the precession of Mercury's orbit and astronomical observations of gravitational lensing. The apparent upward acceleration of the earth's surface is merely a consequence of an otherwise stationary round earth moving through the time element of curved space-time.
https://en.wikipedia.org/wiki/Tests_of_general_relativity
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Your response perfectly illustrates the deflection tactic I predicted at the outset of this thread.
Less of a deflection tactic and more of a Matthew 7:3-5 take on things. As to the rest of your post, I've freely admitted here that GR is not something I'm well versed in. Others here are much more qualified and are doing quite fine at addressing it.
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Things do not "fall" to the ground. The so-called "falling" is nothing more than the result of the Earth accelerating upwards at 9.8 m/s², as evidenced by direct observations and experiments...
...The evidence overwhelmingly supports the upwards acceleration of the surface as the more direct explanation of physical reality
Ah yes, the evidence nobody seems able to produce, so I did my own research. Experimental measurements of acceleration towards the ground by an object falling in a vacuum have been done for many years and at many locations. The OP will insist that these are actually measurements of the earth accelerating towards the object, but it's irrelevant – relative to the object or relative to the Earth, there is undeniable acceleration of one towards the other and this has been measured with great precision.
TL/DR: measured acceleration values of between 9.829 m/s² (Thule, northern Greenland) and 9.772 m/s² (Quito, Ecuador) are documented: these are 0.3% larger and 0.29% smaller than the aforementioned 9.8 metres/second². Acceleration is generally larger nearer the poles, smaller nearer the equator.
https://www.researchgate.net/publication/276278343_Absolute_gravity_measurements_in_South_Africa#pf6
https://library.arcticportal.org/2513/1/A20130416.pdf
https://www.sirgas.org/fileadmin/docs/Boletines/Bol24/45_Guaimaraes_et_al_2019_Absolute_gravimetry_SouthAmerica.pdf
https://apps.dtic.mil/sti/pdfs/ADA099017.pdf
https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2000GL012438
https://www.researchgate.net/publication/350145419_Twelve_Years_of_High_Frequency_Absolute_Gravity_Measurements_at_the_UK%27s_Space_Geodesy_Facility_Systematic_Signals_and_Comparison_with_SLR_Heights/fulltext/609da3ca299bf147699628f2/Twelve-Years-of-High-Frequency-Absolute-Gravity-Measurements-at-the-UKs-Space-Geodesy-Facility-Systematic-Signals-and-Comparison-with-SLR-Heights.pdf
https://geodaesie.info/images/zfv/133-jahrgang-2008/downloads/zfv_2008_3_Timmen_et-al.pdf
https://academic.oup.com/gji/article/217/2/1141/5304614
https://www.researchgate.net/publication/232822567_Absolute_gravity_values_in_Norway
https://www.academia.edu/4418215/Absolute_gravity_measurements_in_India_and_Antarctica
https://backend.orbit.dtu.dk/ws/portalfiles/portal/89119479/PHD_JEMNI_1_.pdf
Acceleration also varies within countries. Within the US, documented acceleration figures vary from 9.788 (Texas) to 9.805 (Missouri) to 9.819 m/s² (Alaska). Norway ranges from 9.818 (Stavanger) to 9.827 m/s² (Honningsvåg). Antarctica records values of 9.826 (twice) and 9.825m/s².
I have rounded the acceleration values measured to three decimal places in all examples.
These variations in acceleration pose a dreadful problem to UA, because they indicate a flat, upwardly accelerating Earth is not accelerating uniformly. The variations in acceleration from the aforementioned 9.8m/s² are only +0.3% to -0.29%, but a little schoolboy physics shows this is catastrophic in practice.
We will start from a stationary flat earth to simplify the calculations. For acceleration a, the distance travelled (from a standing start) in time t is given by:
distance, d = a/2 x t² d in metres, a in m/s², t in seconds.
In one minute (60 seconds), an object accelerating at 9.772 m/s² will travel (9.772/2) x 60² = 17,589.6m. At 9.829m/s² the distance travelled is 17,692.2m. 102.6m difference between largest and smallest distances isn't much across the entirety of a flat earth.
In 10 minutes (600 seconds) the results vary from a minimum of (9.772/2) x 600² = 1,758,960m to a maximum of (9.829/2) x 600² = 1,769,220m, a difference of 10,260m. In just 9 minutes the difference has risen a hundredfold.
In 1 hour (3,600s) the results vary from (9.772/2) x 3600² = 63,322,560m to (9.829/2) x 3600² = 63,691,920m. The difference is now 369,360m or 369.36 kilometres.
In 12 hours (43,200s) we get (9.772/2) x 43200² = 9,118,448,640m at a minimum and (9.829/2) x 43200² = 9,171,636,480m maximum distance travelled. The difference is 53,187,840m.
It has taken 12 hours for areas of a flat earth accelerating upwards at experimentally measured rates to rise by vertical distances differing by up to 53,187.84 kilometres, which is more than five times the distance from the north pole to the equator. If it were even possible for a flat earth to distort by this much, it would no longer be flat, the oceans would be pooling around the tropics and the mountain some believe is at the north pole would in fact be the entire Arctic region. However, the world is not made of pulling taffy, able to stretch at will, and the only sane conclusion is that a flat earth would have been pulled apart by the stresses and reduced to rubble less than 12 hours after starting to accelerate.
The very notion this is the idea Brian Cox is endorsing is ridiculous.
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Einstein already figured that out. That you don't understand it isn't surprising, a lot RE physicists have trouble understanding it too. It's been said that if you think you understand relativity, then you don't understand relativity.
It is correct that a lot of physicists say that they don't understand general relativity, and this thread shows why. It's based on "We know that the earth is round, so it HAS to be this way" and proceeds to creatively theorize elaborate metaphysics of an earth which is exploding apart from itself interdimensionally to explain the acceleration effects.
It's confusing why these mechanisms are being proposed because it is not science, it's a band-aid. When assessed on the topic of the earth's shape we further understand the intricacies of general relativity and the necessity for this.
GR is one of the most thoroughly tested theories ever, starting with the precession of Mercury's orbit and astronomical observations of gravitational lensing. The apparent upward acceleration of the earth's surface is merely a consequence of an otherwise stationary round earth moving through the time element of curved space-time.
https://en.wikipedia.org/wiki/Tests_of_general_relativity
In that link all of the terrestrial tests are the equivalence principle tests that the earth is accelerating upwards.
The astronomical observations such as starlight bending and mercury are indirect inferences. For example:
- Is the only way to explain the observation of light bending bend towards the sun is if the earth is exploding apart from itself in another dimension? Please connect the dots there.
- Is the only way to account for an issue in the precession of Mercury is if the earth is exploding apart from itself in another dimension? Please connect the dots.
There is not a direct connection to the underlying mechanism proposed. It is possible to create different theories of gravity where light bends towards the Sun.
In 1957 Physicist Robert Dicke complained about the shoddy state of General Relativity (https://link.springer.com/content/pdf/10.1140/epjh/e2016-70034-0.pdf) as compared to other fields:
“ Dicke’s thinking about his change of direction of research is illustrated by these quotes from his 1957 Chapel Hill paper, The Experimental Basis of Einstein’s Theory (Dicke 1957a, p. 5):
"It is unfortunate to note that the situation with respect to the experimental checks of general relativity theory is not much better than it was a few years after the theory was discovered – say in 1920. This is in striking contrast to the situation with respect to quantum theory, where we have literally thousands of experimental checks.
...
Professor Wheeler has already discussed the three famous checks of general relativity; this is really very flimsy evidence on which to hang a theory.
...
It is a great challenge to the experimental physicist to try to improve this situation; to try to devise new experiments and refine old ones to give new checks on the theory. We have been accustomed to thinking that gravity can play no role in laboratory-scale experiments; that the gradients are too small, and that all gravitational effects are equivalent to a change of frame of reference. Recently I have been changing my views about this."
In the second of these quotes Dicke was referring to Wheeler’s summary comments on the classical three tests of general relativity: the orbit of the planet Mercury, the gravitational deflection of light passing near the Sun, and the gravitational redshift of light from stars. ”
Quantum Theory had thousands of checks. General Relativity only had a few, and its state has hardly improved today in comparison. It is 2025 and you are still citing Mercury and light bending as your proof.
Beyond that, there has been disagreement these few proofs even work. See: https://wiki.tfes.org/Precession_of_Mercury%27s_Orbit
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TL/DR: measured acceleration values of between 9.829 m/s² (Thule, northern Greenland) and 9.772 m/s² (Quito, Ecuador) are documented: these are 0.3% larger and 0.29% smaller than the aforementioned 9.8 metres/second². Acceleration is generally larger nearer the poles, smaller nearer the equator.
https://www.researchgate.net/publication/276278343_Absolute_gravity_measurements_in_South_Africa#pf6
https://library.arcticportal.org/2513/1/A20130416.pdf
https://www.sirgas.org/fileadmin/docs/Boletines/Bol24/45_Guaimaraes_et_al_2019_Absolute_gravimetry_SouthAmerica.pdf
https://apps.dtic.mil/sti/pdfs/ADA099017.pdf
https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2000GL012438
https://www.researchgate.net/publication/350145419_Twelve_Years_of_High_Frequency_Absolute_Gravity_Measurements_at_the_UK%27s_Space_Geodesy_Facility_Systematic_Signals_and_Comparison_with_SLR_Heights/fulltext/609da3ca299bf147699628f2/Twelve-Years-of-High-Frequency-Absolute-Gravity-Measurements-at-the-UKs-Space-Geodesy-Facility-Systematic-Signals-and-Comparison-with-SLR-Heights.pdf
https://geodaesie.info/images/zfv/133-jahrgang-2008/downloads/zfv_2008_3_Timmen_et-al.pdf
https://academic.oup.com/gji/article/217/2/1141/5304614
https://www.researchgate.net/publication/232822567_Absolute_gravity_values_in_Norway
https://www.academia.edu/4418215/Absolute_gravity_measurements_in_India_and_Antarctica
https://backend.orbit.dtu.dk/ws/portalfiles/portal/89119479/PHD_JEMNI_1_.pdf
Acceleration also varies within countries. Within the US, documented acceleration figures vary from 9.788 (Texas) to 9.805 (Missouri) to 9.819 m/s² (Alaska). Norway ranges from 9.818 (Stavanger) to 9.827 m/s² (Honningsvåg). Antarctica records values of 9.826 (twice) and 9.825m/s².
This is talking about gravimeters. We have a page on this here: https://wiki.tfes.org/Gravimetry
Considering that there are seismometers which have a "gravimeter mode" and there are quotes that a gravimeter is really a seismometer, it's clear that there is something wrong with your interpretation on how this device is measuring gravity. There are also maps showing that the gravitational anomalies across the earth are associated with the seismic zones, further questioning what this device is actually measuring.
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TL/DR: measured acceleration values of between 9.829 m/s² (Thule, northern Greenland) and 9.772 m/s² (Quito, Ecuador) are documented: these are 0.3% larger and 0.29% smaller than the aforementioned 9.8 metres/second². Acceleration is generally larger nearer the poles, smaller nearer the equator.
https://www.researchgate.net/publication/276278343_Absolute_gravity_measurements_in_South_Africa#pf6
https://library.arcticportal.org/2513/1/A20130416.pdf
https://www.sirgas.org/fileadmin/docs/Boletines/Bol24/45_Guaimaraes_et_al_2019_Absolute_gravimetry_SouthAmerica.pdf
https://apps.dtic.mil/sti/pdfs/ADA099017.pdf
https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2000GL012438
https://www.researchgate.net/publication/350145419_Twelve_Years_of_High_Frequency_Absolute_Gravity_Measurements_at_the_UK%27s_Space_Geodesy_Facility_Systematic_Signals_and_Comparison_with_SLR_Heights/fulltext/609da3ca299bf147699628f2/Twelve-Years-of-High-Frequency-Absolute-Gravity-Measurements-at-the-UKs-Space-Geodesy-Facility-Systematic-Signals-and-Comparison-with-SLR-Heights.pdf
https://geodaesie.info/images/zfv/133-jahrgang-2008/downloads/zfv_2008_3_Timmen_et-al.pdf
https://academic.oup.com/gji/article/217/2/1141/5304614
https://www.researchgate.net/publication/232822567_Absolute_gravity_values_in_Norway
https://www.academia.edu/4418215/Absolute_gravity_measurements_in_India_and_Antarctica
https://backend.orbit.dtu.dk/ws/portalfiles/portal/89119479/PHD_JEMNI_1_.pdf
Acceleration also varies within countries. Within the US, documented acceleration figures vary from 9.788 (Texas) to 9.805 (Missouri) to 9.819 m/s² (Alaska). Norway ranges from 9.818 (Stavanger) to 9.827 m/s² (Honningsvåg). Antarctica records values of 9.826 (twice) and 9.825m/s².
This is talking about gravimeters. We have a page on this here: https://wiki.tfes.org/Gravimetry
Considering that there are seismometers which have a "gravimeter mode" and there are quotes that a gravimeter is really a seismometer, it's clear that there is something wrong with your interpretation on how this device is measuring gravity. There are also maps showing that the gravitational anomalies across the earth are associated with the seismic zones, further questioning what this device is actually measuring.
I have read the wiki page on gravimeters, repeatedly, and understand how it suggests a relative gravimeter can be compared with a seismometer. However, I wonder if you actually read my post, because all my citations are from absolute gravimeters:
Experimental measurements of acceleration towards the ground by an object falling in a vacuum have been done for many years and at many locations. The OP will insist that these are actually measurements of the earth accelerating towards the object, but it's irrelevant – relative to the object or relative to the Earth, there is undeniable acceleration of one towards the other and this has been measured with great precision.
If you can explain how an object accelerating towards the ground in a vacuum can detect seismic signals I would be really surprised, because the wiki page doesn't explain it. All the measurements in the cited references are measuring the acceleration of a mass, in a vacuum, towards the ground.
If you can also explain how gravitational anomalies make these acceleration measurements vary both above and below the expected value I should be equally surprised, because the wiki doesn't explain how that might be so. More damningly, the northwest coast of Greenland and Ecuador are the furthest variations above and below, respectively, the expected value. The wiki has a map of gravitational anomalies above and below expected, yet both the Greenland and Ecuador values are in areas of positive anomaly on that map, not one in positive anomaly and the other negative. This is inconsistent with the wiki claim.
Finally, the variations cited in the wiki map https://wiki.tfes.org/Gravimetry#Seismic_Map_Similarities (https://wiki.tfes.org/Gravimetry#Seismic_Map_Similarities) are of up to plus or minus 70 mGal. One mGal is one thousandth of a Gal, one Gal is 1 cm/s² or one hundredth of a metre/s², so one mGal is one hundred thousandth of a metre/s² or 0.00001m/s². 70mGal is therefore 0.0007 m/s² and is too small to register in the quoted 3-decimal-place measurements of 9.827 to 9.772 m/s².
The cited differences in acceleration of an object in a vacuum are therefore too large to be explained by the wiki's quibbling. The upwards-accelerating flat earth would still tear itself to pieces in less than half a day.
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The Wiki covers that. See the section Corrections for Latitude (https://wiki.tfes.org/Gravimetry#Corrections_for_Latitude). There are absolute gravimeters examples where a formula is applied with values for the latitude variations between the equator and poles.
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.geol-amu.org/notes/m10-1-4.htm (https://web.archive.org/web/20190117080418/http://www.geol-amu.org/notes/m10-1-4.htm)
“ 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 may be fallacious.
Note: The reference 'for values relative to a base station' may imply that this is referring to a relative gravimeter.
United Nations University
On p.9 of Seismic Activity, Gravity, and Magnetic Measurements (https://orkustofnun.is/gogn/unu-gtp-sc/UNU-GTP-SC-16-13.pdf) 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.
gn = 978031.85 * (1.0 + 0.005278895 sin 2 (lat) + 0.000023462 sin4(lat)) (mGal) (4)
where lat is latitude ”
“ Free-air corrected gravity (gfa) - The free-air 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, and if the devices were really measuring gravity in full, then these artificial corrections would not be necessary. It is seen that the devices are seismometers and that these corrections are artificially added into the data as modifications.
Absolute Gravimeter Corrections
A common response to some of the references above is to declare that even though the sources do not specify, the sources must solely be talking about relative gravimeters, and that absolute gravimeters are completely different devices which measures gravity in full. Yet, despite this argument we see that even absolute gravimeters determine local gravity through a model involving the gravitational acceleration of the equator and poles.
Terrain-aided navigation with an atomic gravimeter (https://hal.archives-ouvertes.fr/hal-02355711/document)
Introduction
"The purpose of the paper is to provide a solution for surface or sub-surface navigation by Terrain Matching using an absolute gravimeter."
On the third page:
III. A METHOD TO MAP THE GRAVITY ANOMALY WITH THE ATOMIC GRAVIMETER
(https://wiki.tfes.org/images/e/e7/Absolute-local-gravity.png)
Elsewhere it describes that "Φ is the longitude and λ the latitude. g(Φ, λ) is the modulus of the local gravity acceleration vector"
To determine the local gravity acceleration the device invokes a model involving an equation using gravitational acceleration at the equator and poles with the latitude, and the results are then added to the gravity anomaly (Last line: g(Φ, λ) [Local gravity] = g0(λ)[standard gravity accounting for latitude gravity gradient] + ga(Φ, λ) [gravity anomaly]) We see similar equations (sin 2 lat) as in the previous latitude corrections. Why should this be necessary to involve the gravitational accelerations of the equator and poles to determine the local gravity? If an absolute gravimeter is measuring gravity in full then it should measure gravity in full.
Mobile Atom Interferometer
Similarly, we read the following about latitude corrections for a precision free-fall device:
Gravity surveys using a mobile atom interferometer (https://arxiv.org/pdf/1904.09084)
Introduction
“ atomic gravimeters rely on matter-wave interferometry with a freely falling atomic cloud ”
~
Latitude and terrain correction
“ We correct the gravity values collected in the Berkeley Hills for latitude variations using the WGS84 ellipsoidal gravity formula (38) to create latitude-corrected gravity anomalies. ”
~
References and notes for (38)
“ 38. Department of Defense World Geodetic System 1984: Its definition and relationships with local geodetic systems (NIMA Technical Report 8350.2, 3rd ed., National Imagery and Mapping Agency, Washington, DC, USA, 1997). ”
We again see a precision free-fall gravimeter which is corrected for latitude.
WGS84 Ellipsoidal Gravity Formula
On p.13 of a paper titled Invited Review Article: Measurements of the Newtonian constant of gravitation, G (https://aip.scitation.org/doi/pdf/10.1063/1.4994619) we see a summary of the WGS84 ellipsoidal gravity formula:
“ The local acceleration is a sum of the centrifugal acceleration and the gravitational acceleration. At the equator, the local acceleration is reduced by the centrifugal acceleration. This effect is exacerbated by the fact that the figure of the Earth is in response to the centrifugal acceleration an oblate spheroid. Hence the polar radius is smaller than the equatorial radius, increasing the gravitational part of the local acceleration towards the pole. A model describing this normal gravity g0 approximately, the so-called reference ellipsoid, is WGS8497,
(https://wiki.tfes.org/images/thumb/1/16/WGS-ellipsoid-equation.png/860px-WGS-ellipsoid-equation.png)
and Φ denotes the latitude. This formula describes the theoretical local acceleration on an equipotential surface at mean sea level. It includes both gravitational and centrifugal potentials. ”
This is a very similar equation to the absolute gravimeter local gravity equation given in a section previous to this [8](sin 2 lat).
The text around this p.13 quote also strongly indicates that the WGS84 equation for the gravity variations was determined based on the weight change experiments conducted at different latitudes and which affects pendulums and scales. From the sentence immediately prior to the above quote:
“In 1672, Jean Richer noticed on a trip to French Guiana that the oscillation frequency of a seconds pendulum depends on the geographical latitude ”
We hence see that the gravimeters, including absolute gravimeters, are adjusting the output for local gravity based on a latitudinal formula that was determined by a different experiment (Note: This is a determination which may be flawed in interpretation; see Weight Variation by Latitude (https://wiki.tfes.org/Weight_Variation_by_Latitude)). Once again, if the absolute gravimeter is measuring gravity in full, why should equations involving gravity's latitudinal differences of the equator and poles be necessary to determine local gravity?
Absolute gravimeter end product data employ latitude correction formulas, which gives the supposed difference between the equator and the poles. These are values which were derived from a different experiment.
An absolute gravimeter is absolute because the falling object is disconnected from the earth. It allows the vibrations affecting the mirror in the device to be studied with greater accuracy because there is an independent object to compare it to. See this section from the Wiki page:
Absolute Gravimeter Description
From Geophysics From Terrestrial Time‐Variable Gravity Measurements (https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017RG000566) we read about a device that does involve a falling object. The interest is in the tiny noises that affect the mirror in the device while the body is in free fall and disconnected from the Earth:
“ In an absolute gravimeter, a test laser beam bounces off the free‐falling body before being reflected back to the interferometer, where the test beam interferes with a reference one. While the dropped mass is completely isolated from the Earth's vibrations during its fall, anthropogenic and natural microseismic noises continuously modify the position of the reference mirror of the interferometer. Even in the absence of an earthquake, the displacements of the Earth's surface are persistent and location and season dependent, reaching up to a few micrometers close to the coast (Kedar et al., 2008), while one should measure the free‐fall distance at the 1 nm precision level in order to achieve a precision on gravity of 10 nm/s^2. In the first white‐light gravimeter, the measurements of gravity were corrected by using the records from a 1 s period seismometer. Early in the 1980s, Rinker (1983) developed the so‐called Super Spring, that is, a modified seismometer providing an inertial reference system at periods shorter than about 1 min—the suspended mass of a seismometer provides an inertial reference frame, independent from the motions of the Earth, at periods shorter than the resonance frequency (Aki & Richards, 2002). The challenge consisted in producing a suspension device of which the free period is about 1 min, that is, longer than the periods ranging 5–20 s, where microseism is the strongest. ”
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Some of the absolute gravimeter articles you posted actually reference corrections. See this:
https://www.sirgas.org/fileadmin/docs/Boletines/Bol24/45_Guaimaraes_et_al_2019_Absolute_gravimetry_SouthAmerica.pdf
Measurements 2010 - Today
The A-10 nº 032
- The process is controlled by a computer that corrects the
luni-solar attraction, the effect of rotation of the Earth,
the ocean load and the barometric pressure, providing a
final “g” value;
- The final value of absolute gravity is an adjustment of all
observations in the different sets, after corrections.
The "effect of the rotation of the Earth" is the difference of g you are referring to between the equator and poles, which is allegedly due to the earth's rotation. The above section is saying that there is a built-in correction. Since a correction is needed to account for it in the final end product data, it tells us that the gravimeter is not detecting this.
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The Wiki covers that. See the section Corrections for Latitude (https://wiki.tfes.org/Gravimetry#Corrections_for_Latitude).
The wiki covers this? Covers it in muddled thinking and errors, and anyone wanting to learn something about gravimetry and gravimeters should look elsewhere – even Wikipedia is a better choice.
Where to start? From the wiki, as quoted above:–
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.
Frankly, the wiki gets this bass ackwards. It also mentions a fictitious "vibrating gravity theory" – where did that derp come from?
First, the theoretical model, which has an equation (cited above) giving the theoretical value of gravitational acceleration at the geoid level for anywhere on Earth, accurate to one tenth of a mgal (milligal) – that's 0.00001 m/s². There is also a more elaborate equation which gives results accurate to a ten-thousandth of a mgal (0.0000001 m/s² – a thousand times more accurate) if needed. Pick your location, plug the latitude into the equation and you get a theoretical value for acceleration at geoid level (generally, but not always, equal to sea level).
Next, the gravity survey. Surveyors measure the acceleration directly with an absolute gravimeter, or the difference from a known, accurate measurement of gravitational acceleration with a relative gravimeter. Then there are corrections applied to the measured value, not the theoretical value. The theoretical value is for geoid level, but an absolute gravimeter measurement at Emigrant Gap, CA on Interstate 80, is at 1582m or 5190ft above sea level. Gravity does reduce with height, so a correction to give the expected value at geoid level is applied to the measurement – this is the Free Air correction. There is also a great deal of rock in those 1582m above the geoid and this is also corrected for – this is the Bouguer correction.
Let's say the surveyors are instead using a relative gravimeter and the known accurate measurement they are comparing with is at Sacramento, CA. A Latitude correction is applied to the Sacramento figure to account for the 42 minutes and 55 seconds difference in latitude between Sacramento and Emigrant Gap, because gravity does vary with latitude.
Note well – no corrections are applied to the theoretical value – all corrections are applied to the measured data. All these corrections are to give a measurement for gravitational acceleration corrected to geoid level, as if the surveyors were actually measuring at the theoretical geoid level, so comparisons can be made from other places, also corrected to the geoid level, making sure surveyors are comparing apples with apples, not coconuts with bananas.
The corrected, measured values are then compared with the theoretical values and the difference, if any, noted – this difference is the gravitational anomaly. Maps of the gravitational anomaly over a given area are used for many purposes, including oil and mineral prospecting, and are a valuable tool. The Nash dome in Texas was the first oil discovery made using an early type of gravimeter (in the 1920s) and many have followed since.
What's missing from the wiki, or any of the examples you've mentioned, are numbers: actual data and actual calculations. Do your vaguely expressed doubts stand up to examination? It's time to do some more calculations using a more reliable introductory guide.
https://gpg.geosci.xyz/content/gravity/gravity_introduction.html
The data reduction formulas are given on https://gpg.geosci.xyz/content/gravity/gravity_data.html
Let's use the Emigrant Gap site to start with. I'll assume the geoid coincides with sea level for these calculations and I'll use the suggested "crustal" density figure for Bouguer calculations. The Free Air correction is 0.3086 x 1582 = 488.2mgal, which is added to the measured figure. The Bouguer correction is 0.04191 x 1582 x 2.67 = 177.0mgal which is subtracted from the measured figure. The net adjustment is therefore 488.2 - 177.0 = +311.2mgal and would be applied to a measurement made by an absolute gravimeter.
If the surveyor was instead using a relative gravimeter, the latitude correction would also be made for the difference in latitude between Sacramento and Emigrant Gap, which is 42.9 nautical miles or 79.5km. Latitude of Sacramento is 38° 34' 54"N and Emigrant Gap is 39° 17' 49"N, so I'll use 39° as an average. Latitude correction is therefore 0.811 x sin(2x39) x 79.5 = 63.1mgal and this is subtracted from the measurement to directly compare with the Sacramento figure. The net adjustment for a relative gravimeter is therefore +311.2 - 63.1 = +248.1mgal.
The acceleration figure I found for Sacramento was 9.80033m/s², which is 980.033 Gal, or 980,033mgal, but an adjustment of 311.2 mgal (or 248.1mgal) is hardly significant compared to the headline figure, or the figures cited from around the world, but we'll have a look at the extremes of that range (9.772 to 9.829m/s²) to make sure. These were all made with absolute gravimeters, so we can ignore latitude corrections.
Quito in Ecuador is at 2850m above sea level. Free air correction is 0.3086 x 2850 = 879.5mgal. Bouguer correction is 0.04191 x 2850 x 2.67 = 318.9mgal. The net adjustment is +879.5 - 318.9 = +560.5mgal. The cited acceleration figure is 9.772 m/s², which is 977,200 mgal. 560.5mgal are pretty small beer next to the headline figure.
Thule Air Base in Greenland, now known as Pituffik Space Base, is at 76.5m above sea level. Free air correction is 0.3086 x 76.5 = 23.6mgal. Bouguer correction is 0.04191 x 76.5 x 2.67 = 8.56. Net correction is +23.6 - 8.56 = +15.04mgal. This is tiny in comparison to the cited 9.829 m/s² or 982,900mgal.
The cited gravitational acceleration figures are so many orders of magnitude larger than the corrections applied to their direct measurement that there is no justifiable hope the corrections might account for the differences across the world. An upwardly accelerating flat earth would still self-destruct in less than half a day.
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Frankly, the wiki gets this bass ackwards. It also mentions a fictitious "vibrating gravity theory" – where did that derp come from?
That is expressly described in the Wiki. The gravimeter is a seismometer which is detecting "gravity waves". Immediately prior to the Corrections for Latitude section there is the section Gravity Wave Theory (https://wiki.tfes.org/Gravimetry#Gravity_Wave_Theory)
Gravity Wave Theory
A study titled Seafloor Compliance Observed by Long-Period Pressure and Displacement Measurement (https://web.archive.org/web/20190118051920/http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.476.7455&rep=rep1&type=pdf) uses gravimeters to study the gravity of the ocean. On p.2, para.4 its authors call the gravimeter a long-period seismometer.
“ We have collected vertical compliance data using a gravimeter (long-period seismometer) and a differential pressure gauge ”
On the same page we read about the theory behind the measurements:
(https://wiki.tfes.org/images/4/4f/Gravity_Wave_Theory.png)
We see that the theory behind the measurements involve the theories of "Gravity Waves" and "Infragravity Waves". Wikipedia describes them as:
https://en.wikipedia.org/wiki/Gravity_wave
“ In fluid dynamics, gravity waves are waves generated in a fluid medium or at the interface between two media when the force of gravity or buoyancy tries to restore equilibrium. An example of such an interface is that between the atmosphere and the ocean, which gives rise to wind waves.
A gravity wave results when fluid is displaced from a position of equilibrium. The restoration of the fluid to equilibrium will produce a movement of the fluid back and forth, called a wave orbit.[1] Gravity waves on an air–sea interface of the ocean are called surface gravity waves or surface waves, while gravity waves that are within the body of the water (such as between parts of different densities) are called internal waves. Wind-generated waves on the water surface are examples of gravity waves, as are tsunamis and ocean tides. ”
https://en.wikipedia.org/wiki/Infragravity_wave
“ Infragravity waves are surface gravity waves with frequencies lower than the wind waves – consisting of both wind sea and swell – thus corresponding with the part of the wave spectrum lower than the frequencies directly generated by forcing through the wind.
Infragravity waves are ocean surface gravity waves generated by ocean waves of shorter periods. The amplitude of infragravity waves is most relevant in shallow water, in particular along coastlines hit by high amplitude and long period wind waves and ocean swells. Wind waves and ocean swells are shorter, with typical dominant periods of 1 to 25 s. In contrast, the dominant period of infragravity waves is typically 80 to 300 s,[1] which is close to the typical periods of tsunamis, with which they share similar propagation properties including very fast celerities in deep water. This distinguishes infragravity waves from normal oceanic gravity waves, which are created by wind acting on the surface of the sea, and are slower than the generating wind. ”
Essentially, the "Gravity Waves" are slight motions and vibrations picked up by the gravimeter (seismometer). A chart is provided, showing the frequencies that the winds and tides appear in:
(https://wiki.tfes.org/images/thumb/0/08/Gravity_Waves_Chart.svg/1600px-Gravity_Waves_Chart.svg.png)
In line with the previous seismometer section, the tides appear on the low frequency bands.
This isn't the direct measurement of gravity that you want this to be. The unit of measurement is hertz (hz). These are tiny vibrations, hence the many references that gravimeters are seismometers and that seismometers can detect gravity.
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If the surveyor was instead using a relative gravimeter, the latitude correction would also be made for the difference in latitude between Sacramento and Emigrant Gap, which is 42.9 nautical miles or 79.5km.
Your opinion is contradicted by your own sources. It's not only relative gravimeters where the results are corrected by latitude. The source you provided, 30 years of absolute gravity measurements in South America (https://www.sirgas.org/fileadmin/docs/Boletines/Bol24/45_Guaimaraes_et_al_2019_Absolute_gravimetry_SouthAmerica.pdf), said that the absolute gravimeter corrects for "the effect of the rotation of the Earth", which means all of it.
The process is controlled by a computer that corrects the
luni-solar attraction, the effect of rotation of the Earth,
the ocean load and the barometric pressure, providing a
final “g” value;
This paper below describes both absolute and relative gravimeters, and then goes on to say that "gravimeters do not give direct measurements of gravity". This means that neither kind of gravimeter is measuring gravity directly.
https://gogn.orkustofnun.is/unu-gtp-sc/UNU-GTP-SC-16-13.pdf
3.4 Measurements of gravity
There are two kinds of gravity meters. An absolute gravimeter measures the actual value of g by
measuring the speed of a falling mass using a laser beam. Although this meter achieves precisions of
0.01to 0.001 mGal (milliGals, or 1/1000 Gal), they are expensive, heavy, and bulky. A second type of
gravity meter measures relative changes in g between two locations, see Figure 6.
....
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.
This statement that gravimeters are not detecting gravity directly shows that you are incorrect. As you describe it, an absolute gravimeter should be detecting gravity in full. Instead, it is really analyzing the vibration of the mirrors while the falling object is disconnected from the device for a more accurate comparison. It is using the same seismic gravity phenomena as the other referenced gravimeter devices, not something completely different.
It is absolute because the body in freefall is disconnected and not vibrating with the device, allowing a better measurement.
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Frankly, the wiki gets this bass ackwards. It also mentions a fictitious "vibrating gravity theory" – where did that derp come from?
That is expressly described in the Wiki. The gravimeter is a seismometer which is detecting "gravity waves". Immediately prior to the Corrections for Latitude section there is the section Gravity Wave Theory (https://wiki.tfes.org/Gravimetry#Gravity_Wave_Theory)
Gravity Wave Theory
A study titled Seafloor Compliance Observed by Long-Period Pressure and Displacement Measurement (https://web.archive.org/web/20190118051920/http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.476.7455&rep=rep1&type=pdf) uses gravimeters to study the gravity of the ocean. On p.2, para.4 its authors call the gravimeter a long-period seismometer...
Do you ever read and try to understand the material you cite? The "Seafloor Compliance" study is about deformation of the sea floor under pressure from water waves. You have read the terms "gravity wave", "infragravity wave" and "ultragravity wave" and thought this must be how gravity is detected, but nowhere in that study is measuring acceleration due to gravity even mentioned, nor is a measured gravitational acceleration given. The extensive quoting from Wikipedia is irrelevant. Your cherry-picking has yielded ... a zucchini. How disappointing.
And then we have another citation:
... This paper below describes both absolute and relative gravimeters, and then goes on to say that "gravimeters do not give direct measurements of gravity". This means that neither kind of gravimeter is measuring gravity directly.
https://gogn.orkustofnun.is/unu-gtp-sc/UNU-GTP-SC-16-13.pdf
3.4 Measurements of gravity
There are two kinds of gravity meters. An absolute gravimeter measures the actual value of g by
measuring the speed of a falling mass using a laser beam....
....
3.6 Reduction of data
Gravimeters do not give direct measurements of gravity; rather, a meter reading is taken which is then...
So absolute gravimeters measure the actual value of g, but gravimeters do not give direct measurements of gravity? You're not making sense.
I could produce references and citations about relative and absolute gravimeters, what they measure and how they measure it, but I expect we'll get into a round of "he said, she said" so let's consult the people who ought to know; the gravimeter manufacturers.
One of them is Micro–g LaCoste of Colorado. They manufacture the gPhoneX relative gravimeter, (https://microglacoste.com/product/gphonex-gravimeter/), which is a modern development of the older, purely mechanical LaCoste & Romberg or Worden gravimeters (https://gpg.geosci.xyz/content/gravity/gravity_data.html) This doesn't directly measure gravitational acceleration, but gives a reading compared to a known gravitational acceleration measurement. The readings are electronic and can be logged on a computer, which is why it "can also be used as an ultra sensitive low frequency seismometer". So that's a gravimeter which can be used as a seismometer.
Then there's their CG-6 Autograv portable survey gravimeter (https://microglacoste.com/product/cg-6-autograv-gravity-meter/) This has a much wider operating range, but can't be used as a seismometer. The SEA III Marine Gravity System is for use on ships (https://microglacoste.com/product/sea-iii-marine-gravity-system/) and the TAGS-7 Dynamic Gravity Meter is for aircraft (https://microglacoste.com/product/tags-7-dynamic-gravity-meter/) and neither of these double as seismometers – it's hard to think how an aircraft-based device could. Interestingly, Micro-g quote the range of variations of g across the world in the SEA III brochure (https://microglacoste.com/wp-content/uploads/2024/11/SEAIII-Brochure_R13.pdf)Earth’s gravity varies from 978 to 983 Gals at sea level (full change of 5 Gal)
How do they know that? Because for over 80 years they have been making the instruments that measured it!
Micro–g also build the A10 Portable Absolute Gravity Meter (https://microglacoste.com/product/a10-outdoor-absolute-gravimeter/) and the FG-5X Absolute Gravity Meter (https://microglacoste.com/product/fg5-x-absolute-gravimeter/) which both use a dropping mass to measure gravitational acceleration directly. The FG-5X is the standard by which all the rest are judged and by which all the rest are calibrated, but these two are where you have got tangled up with the daft idea these machines monitor the bottom mirror for tiny vibrations to measure gravity.
From the A10 brochure:
The A10 operates by using a free-fall method. An object is dropped inside a vacuum chamber and its position is monitored very accurately using a laser interferometer. In 2004, the BIPM (Bureau International de Poids et Mesures) proclaimed the ballistic freefall method as an official primary method for measuring gravity.
The free-fall trajectory of the dropped object is referenced to a very stable active-spring system called a “Superspring”. The Superspring provides seismic-isolation for the reference optic to improve the noise performance of the A10.
The optical fringes generated in the interferometer provide a very accurate distance measurement system that can be traced to absolute wavelength standards. Very accurate and precise timing of the occurrence of these optical fringes is done using an atomic rubidium clock that is also referenced to absolute standards.
The measurement is directly tied to international standards, and this is what makes the A10 an absolute gravimeter. By basing the measurement on these standards, the system is inherently calibrated and will neither drift nor tare over time. (https://microglacoste.com/wp-content/uploads/2017/03/Brochure-A10.pdf)
The same is true for the FG-5X. The bottom mirror is isolated from vibrations of the meter body by the Superspring mechanism, so gravitational acceleration is being measured by very precise timing of the fall of the top mirror in the vacuum and only by that means.
I think the person who originally came up with Universal Acceleration was trolling you and the wiki has swallowed that troll – hook, line and sinker. You would do well to forget the whole idea, which carries the seeds of its own destruction in the variations in gravitational acceleration across the world, which would tear an upwardly accelerating Earth apart.
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Do you ever read and try to understand the material you cite? The "Seafloor Compliance" study is about deformation of the sea floor under pressure from water waves. You have read the terms "gravity wave", "infragravity wave" and "ultragravity wave" and thought this must be how gravity is detected, but nowhere in that study is measuring acceleration due to gravity even mentioned, nor is a measured gravitational acceleration given.
Yes, I did read it. It says that a gravimeter is reading these "gravity waves" which are measured in Hz, therefore a gravimeter is a seismic detecting device. It also shows that seismic data is interpreted as gravity data. The fundamental error here is in not understanding the principled of what is being detected.
Your argument that only some gravimeters are seismometers is spurious. They are all seismometers, and are all measuring the same principle of gravity. We have seen enough information to show that this is the case.
Here is an example of an absolute gravimeters detecting "Gravity Waves". See the caption of the below image:
https://www.researchgate.net/profile/Christian-Ullrich-2/publication/304612229_Poster_Presentation_EGU2016/links/5774c48a08ae4645d60a16c7/Poster-Presentation-EGU2016.pdf
Measurements and Processing:
The absolute gravity measurements in this project were performed with the Austrian absolute gravimeter FG5-242
of BEV and were recorded over two nights and one day at each station; that minimizes errors due to the
determination of the tides correction. Merely at station Saranda the measurements could only be performed during
one night and a half day. Between 4500 and 7000 drops were used at each station for absolute gravity calculation.
Two or three runs (with different laser wavelengths) were performed at each station. The average weighted value of the runs at an absolute gravity stations ( see figure 6,7 and 8 ) is the final absolute gravity value which refers to
exactly 122 cm above the benchmark of each station
(https://i.imgur.com/HKqBTG7.png)
In the caption we see reference to detecting gravity waves. The "correlative mean" on 30 September is given as 980270189.75 uGal, but we see in the chart that the actual values presented are very low. The values go above and below 0 over time, just like a seismometer.
A falling object provides an independent reference against the vibrations of the device. It does not make sense that only some kind of gravimeters are basing their fundamentals on the seismic interpretation of gravity, considering that we read that absolute gravimeters detect gravity waves and also produce data which looks like a seismic chart. We will need to see more information from you that an absolute gravimeter operates on a completely different version of gravimetry.
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Do you ever read and try to understand the material you cite? The "Seafloor Compliance" study is about deformation of the sea floor under pressure from water waves. You have read the terms "gravity wave", "infragravity wave" and "ultragravity wave" and thought this must be how gravity is detected, but nowhere in that study is measuring acceleration due to gravity even mentioned, nor is a measured gravitational acceleration given.
Yes, I did read it. It says that a gravimeter is reading these "gravity waves" which are measured in Hz, therefore a gravimeter is a seismic detecting device. It also shows that seismic data is interpreted as gravity data. The fundamental error here is in not understanding the principled of what is being detected.
The paper explicitly says the gravimeter is measuring seafloor acceleration:
We use a LaCoste-Romberg underwater gravimeter to measure seafloor acceleration [Lacoste, 1967; Hildebrand et al., 1990]. This sensor is used as a long-period seismometer on land [Agnew and Berger, 1978] and its useful frequency range is two decades lower than typical ocean bottom seismometers
This seafloor acceleration is compared with water wave pressure. The fundamental error here is not understanding what is being measured.
In the caption we see reference to detecting gravity waves. The "correlative mean" on 30 September is given as 980270189.75 uGal, but we see in the chart that the actual values presented are very low. The values go above and below 0 over time, just like a seismometer .... we read that absolute gravimeters detect gravity waves and also produce data which looks like a seismic chart.
At last, an explanation. Finally, some reasons behind the erroneous claims of what gravimeters do. Unfortunately, they are based on glaring misunderstandings.
Micro-g Lacoste supply "g9" software with the A10 and FG5-X absolute gravimeters already mentioned, both of which are free-fall instruments dropping a reference object in a vacuum. The software reads data from the gravimeter and also controls its operation.
https://microglacoste.com/download/g9-users-manual/
How g[9] Processes Gravity Data
This manual assumes the user is familiar with the operation of a Micro-g LaCoste freefall gravimeter. An object is dropped in a vacuum and a laser interferometer is used to accurately track the freefall. The precise timing of optical fringes (which provide distance information) allows the acceleration of gravity, g, to be determined.
The gravimeter times the drop of an object, measures how far it drops and the software calculates the acceleration of gravity from that information – this is repeated many times and the results aggregated. The gravimeter is programmed by the user to perform a prescribed number of drops and these constitute a set of data. The user also programs how many of these sets are performed and these constitute a project. So the user can look at the acceleration for a particular drop, the average acceleration for a set of drops and the average acceleration for all the sets. All the data is preserved. The user can also set the time beween drops and how long to wait between finishing one set and starting another.
(https://i.imgur.com/kqYW5Q1.jpg)
This is an example from the g9 software. The project was to make 12 sets of 100 drops, 1200 in all. The most recent drop, drop #100 in the current set, gave a corrected figure of 979647287.69 μgal (microgal). The current set is set #2 and the average corrected figure for the set is 979647288.94 μgal. The project corrected average is 979647289.79 μgal across all the drops measured so far, only 2.1 μgal different from the individual drop shown. That’s 2.1 hundred millionths of a m/s².
(https://i.imgur.com/03e4Utj.jpg)
https://microglacoste.com/wp-content/uploads/2017/03/Brochure-A10.pdf
This is data recorded in a single set of 120 drops. Each green dot represents a single measurement of gravitational acceleration. The chart also gives the measurement of the latest drop, 979631880.39 μgal which is #120 in the set.
(https://i.imgur.com/TaAmA7N.jpg)
This is data from 16 sets of measurements. Each dot represents the average of the measurements and the vertical line at each dot represents the error bar for the set. (this should look familiar)
Anyone can see the data from the gravimeter is discrete values, not a continuous reading like that from a seismograph:
(https://www.researchgate.net/profile/Codrin-Donciu/publication/366458878/figure/fig2/AS:11431281118234473@1675697733420/Typical-seismogram-21.jpg)
https://www.researchgate.net/profile/Codrin-Donciu/publication/366458878/figure/fig2/AS:11431281118234473@1675697733420/Typical-seismogram-21.jpg
However, the much more important misunderstanding is in reading the data charts, which are actually scatter charts.
...we see in the chart that the actual values presented are very low. The values go above and below 0 over time, just like a seismometer.
No, they don't, that type of scatter chart shows the small variations above and below the "correlative mean". A point at -5μgal on the chart is a value of the correlative mean minus 5μgal, a point at +2.2μgal represents the cumulative mean plus 2.2μgal. This type of scatter chart is commonly used in gravimeter-related literature, but if you're not familiar with it, this is an easy mistake to make. Nevertheless, if the measurement were really of very small acceleration values, where then would the "correlative mean" figure come from? You have no idea.
No frequency data is recorded by the gravimeter. No data of seismic vibrations is to be seen in the data. It's obvious that a free-fall gravimeter is not a seismometer, period.
Finally, here's a scatter chart of drop set measurements from a prototype freefall drop gravimeter which unusually uses a conventional scale to show acceleration results. Note the individual points and their error bars:
(https://i.imgur.com/PphT0aQ.jpg)
https://repository.geologyscience.ru/bitstream/handle/123456789/33805/Fall_03.pdf?sequence=1
I hope you now see and understand where the ideas of a "seismic interpretation of gravity" and "vibrating gravity theory" have gone badly wrong. I don't know whether they are your ideas or someone else's, but like UA you would do well to forget them.