[QED]

Whoa, just hold on a second. You need to parse these ideas in smaller, more manageable discussable chunks. We can’t have a good online discussion otherwise - it becomes impractical to address everything as it tangents off from a wall of text.

Let me reorganise a bit, and please reply with your thoughts again.

1. Gravity as a force vs gravity as a deformation of space time.

Okay. The two don’t work in the same discussion together. We can talk about Newtonian gravity, which works well in the regime of the weak field limit. That is, GR reduces to Newton very well on the surface of the earth.

The normal force is the Newton’s 3rd law pair. When I stand on the ground, the gravitational force acts down. So why don’t I move down? Cause the ground is there. Obviously. But since f=ma and my a is zero when standing, there must be a force which counteracts gravity. That is the normal force. It is the force of the ground on me that stops me sinking through it.

What I feel is THAT force. Same thing when you take a turn too quickly. You feel pushed up against the side of the car. You are feeling the normal force from the side of the car.

Okay. That is what you feel. You don’t really feel your weight much. But this is more psychological in nature - what you feel vs what is actually happening.

2. GR. So it’s hard to parse your GR discussion. Understand the geometry of spacetime is very very difficult, and solving the equations for how this geometry warps in the vicinity of mass is even harder. I have never heard these terms of packed energy and kinetic vectors in my study of GR. The objects we really to discuss are metrics, Riemann curvature tensors, stress-energy tensors, and cristoffel symbols. But I don’t know if a forum will suffice for delving deeply into these concepts - the math really is prohibitively difficult.

[spherical]

Whoa, just hold on a second. You need to parse these ideas in smaller, more manageable discussable chunks. We can’t have a good online discussion otherwise - it becomes impractical to address everything as it tangents off from a wall of text.

Let me reorganise a bit, and please reply with your thoughts again.

1. Gravity as a force vs gravity as a deformation of space time.

Okay. The two don’t work in the same discussion together. We can talk about Newtonian gravity, which works well in the regime of the weak field limit. That is, GR reduces to Newton very well on the surface of the earth.

The normal force is the Newton’s 3rd law pair. When I stand on the ground, the gravitational force acts down. So why don’t I move down? Cause the ground is there. Obviously. But since f=ma and my a is zero when standing, there must be a force which counteracts gravity. That is the normal force. It is the force of the ground on me that stops me sinking through it.

What keeps you on your feet while standing over a concrete slab?  It is not any "normal force", it is purely density of mass holding your sliding toward the space deformation.   Of course that if you relax your muscles you will fall over the concrete, space deformation will slide you down, if the soil under the concrete slab becomes less dense, it will slide sinking into the soil (Florida have several sink holes to prove it).  The sliding vector is always present, trying to move you towards the stronger deformation, there is no way to avoid it.    There is no force at all, there is only space deformation, less dense property of the space.

There is no force holding the book over the table, the space deformation generated by the huge mass of the planet is trying to slide the book down, but the table is just holding it there.  A "force" require some energy in first place.  One explanation of force:  "strength or energy as an attribute of physical action or movement".  Now, think the whole planet and all over it, including the table and the book were in space floating, very apart, by molecules, and slowing all of it slide towards a common center with little space with less density, it took millions of years to do that. Where that huge "force" that pushed everything together comes from? what about the huge force that holds all the tectonic plates over the melting ball of lava comes from?  What generated such huge amount of energy?  It is much easier to think about a space density becoming smaller, mass sliding towards where it is less dense, some mass can't go ahead because something is in the way, a table for example.

"Force" is a simple and easy way to explain in layman terms what we barely understand.
I hear it everyday, "the force of gravity"... it is not.

Force is when I push a chair, there is a muscle mechanic action, based on energy, it promotes a new vector to the balanced space around the chair, it moves.  That is force, because it was not there before, it was generated, used and converted.  A car's engine piston moves by the force of the fuel exploding, such energy can be wasted.  Gravity is not generated, imposed, used or wasted, you can not, because it is not a force.   You can convert the potential energy stored in the hydroelectric water, but it is not a force offered by gravity. The solar energy evaporated all that water and transferred energy to it - well, not really, the water didn't change, you can not measure such energy, but it is there, in a "potential" way, it means, "it potentially can be used".  Gravity is just the slider where the water runs and allows the turbines and generators to extract such energy.  Gravity sliding action will still the same after the water energy is collected, before, while and after.  If it can not be changed, converted or wasted, it is not a force.

Cheers.

[QED]

Whoa, just hold on a second. You need to parse these ideas in smaller, more manageable discussable chunks. We can’t have a good online discussion otherwise - it becomes impractical to address everything as it tangents off from a wall of text.

Let me reorganise a bit, and please reply with your thoughts again.

1. Gravity as a force vs gravity as a deformation of space time.

Okay. The two don’t work in the same discussion together. We can talk about Newtonian gravity, which works well in the regime of the weak field limit. That is, GR reduces to Newton very well on the surface of the earth.

The normal force is the Newton’s 3rd law pair. When I stand on the ground, the gravitational force acts down. So why don’t I move down? Cause the ground is there. Obviously. But since f=ma and my a is zero when standing, there must be a force which counteracts gravity. That is the normal force. It is the force of the ground on me that stops me sinking through it.

What keeps you on your feet while standing over a concrete slab?  It is not any "normal force", it is purely density of mass holding your sliding toward the space deformation.   Of course that if you relax your muscles you will fall over the concrete, space deformation will slide you down, if the soil under the concrete slab becomes less dense, it will slide sinking into the soil (Florida have several sink holes to prove it).  The sliding vector is always present, trying to move you towards the stronger deformation, there is no way to avoid it.    There is no force at all, there is only space deformation, less dense property of the space.

There is no force holding the book over the table, the space deformation generated by the huge mass of the planet is trying to slide the book down, but the table is just holding it there.  A "force" require some energy in first place.  One explanation of force:  "strength or energy as an attribute of physical action or movement".  Now, think the whole planet and all over it, including the table and the book were in space floating, very apart, by molecules, and slowing all of it slide towards a common center with little space with less density, it took millions of years to do that. Where that huge "force" that pushed everything together comes from? what about the huge force that holds all the tectonic plates over the melting ball of lava comes from?  What generated such huge amount of energy?  It is much easier to think about a space density becoming smaller, mass sliding towards where it is less dense, some mass can't go ahead because something is in the way, a table for example.

"Force" is a simple and easy way to explain in layman terms what we barely understand.
I hear it everyday, "the force of gravity"... it is not.

Force is when I push a chair, there is a muscle mechanic action, based on energy, it promotes a new vector to the balanced space around the chair, it moves.  That is force, because it was not there before, it was generated, used and converted.  A car's engine piston moves by the force of the fuel exploding, such energy can be wasted.  Gravity is not generated, imposed, used or wasted, you can not, because it is not a force.   You can convert the potential energy stored in the hydroelectric water, but it is not a force offered by gravity. The solar energy evaporated all that water and transferred energy to it - well, not really, the water didn't change, you can not measure such energy, but it is there, in a "potential" way, it means, "it potentially can be used".  Gravity is just the slider where the water runs and allows the turbines and generators to extract such energy.  Gravity sliding action will still the same after the water energy is collected, before, while and after.  If it can not be changed, converted or wasted, it is not a force.

Cheers.

This does not accord with any accepted description in physics.

What keeps you on your feet in a space station that simulates gravity through centripetal rotation? The normal force.

Gravity is a force and arises from a potential. It can be generated, and this has been measured. It can be wasted - this has been measured too. Gravity certainly can be used - this is how we obtain energy in hydroelectric power plants.

Potential energy does not mean it potentially can be used. Potential energy is the energy associated with specific configurations within a system. Some potential energies are not accessible for mechanical work.

You will not find “muscle mechanic action based on energy” in any physics textbook on the planet. It sounds to me like you are making stuff up.

[Galieo005]

It has been measured that objects weigh less at the top of a mountain than at sea level. If the earth was accelerating upwards there should be no change in weight. How dos the flat earth model explain this?

[markjo]

Some FE models introduce the concept of celestial gravitation where the heavenly bodies influence the weight of objects as they get higher.

[WellRoundedIndividual]

I mean, conceptually, if you accepted the premise of UA, a flat earth, and celestial gravitation, it would make sense that as you get closer to a celestial object that it may have some sort of gravitational pull on you. I mean, I think even FE accepts that the moon has some effect on the tide, correct? But if this was correct, then gravity anomaly differences would be consistent across all altitudes and locations (x,y or lat and long) - meaning the higher you go the bigger the effect, no matter what mountain you are on. However, this has been demonstrated to be false. It is not consistent. And is in fact due to multiple factors. Read up on the Bouguer anomaly and how rock density also effects the gravity anomaly.

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

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

So while we may conceded that there is some sort of celestial gravitation (given that we see this with the moon), it is also dependent on features within the terrain - and therefore is further evidence for a spherical earth having gravity. UA would not be able to explain this (aka it cant have trouble pushing through denser rock, if it is pushing the entire flat earth at the same time).

[spherical]

Gravity is a force and arises from a potential. It can be generated, and this has been measured. It can be wasted - this has been measured too. Gravity certainly can be used - this is how we obtain energy in hydroelectric power plants.

You are confusing "gravity as a force", because you are thinking it is gravity what causes the water to slide down through the hydroelectric turbines, it is not.  Gravity offers the way for that to happens, but it is the free sliding of the water through a less dense space that cause the turbines to rotate.  No gravity is wasted, used, consumed, in the process.   The energy conversion to electricity comes from the water movement, once it moved, there is no more energy to be absorbed, so, the energy was in the water, promoted by the solar radiation creating water evaporation, not in the gravity.

You can not reuse the energy in the gasoline that creates the explosion inside the piston in the Otto engine.  When the energy is converted, it is done. You can turn blue trying to convince people that was the piston pressure that created the explosion, but no, it was not.  The piston pressure created the ideal environment for a compressed fuel and oxidizer to reach a favorable situation for an explosion, a spark initiate that, on diesel not even spark.  See, the piston pressure will serve for nothing without those energy packing elements.  The energy acquired in an Otto engine, is directly obtained from the fuel's energy.

This is exactly why perpetual machines doesn't work, it can be based on gravity, magnetic, whatever.  The energy to be produced from the perpetual machine can not be extracted from gravity or magnetic, they can not be the main supplier for such energy, they just are used as part of the environment where the energy can be converted from another force, mostly mechanical, but such force is in fact the ones providing the energy to be converted.

An electric generator is a good example.  It has magnets, coils, rotating parts, contact collars, etc, it uses the known law of pushing electrons flow into an electric conductor when it crosses magnetic field lines.  But see, it needs to be "crossing" magnetic field lines, a stationary copper wire in middle of those steady lines generates nothing.  Even with the most gigantic magnet close to the wire generates absolutely nothing.   The mechanical movement of the wire (or the magnet) does it, and to do so, it needs an external force, a movement, a job, that will finally convert energy from one form to another.  It is not the magnet that does it, the magnet does not contain such force or energy.  The magnet is what creates the right environment for such conversion to take place.  See, when the wire crosses the magnetic line fields, what is converted is the energy from the movement force, it is wasted, converted, it disappears after that and appears in the form of electricity.  The magnet never change its magnetic fields, it does not become weak, change, move, or become wasted, because it IS NOT used in the process.  Exactly like gravity.

[spherical]

Gravity is a force and arises from a potential. It can be generated, and this has been measured. It can be wasted - this has been measured too. Gravity certainly can be used - this is how we obtain energy in hydroelectric power plants.

Of course "gravity" can be generated, you can convert energy into mass, that mass will promote space deformation, thus, sliding vectors toward the center of such deformation, where space is less dense.   But that is it.

But sorry, you can not measure gravity, there is no over the counter equipment to do it, what you may be thinking is that we can measure the sliding vector of a mass towards another, using a common bathroom scale, that layman terms known as "weight".  That is not a gravity measurement device, sorry.  See, photons have no mass, but they have momentum, that can allow them to slide through the space deformation and change path.  You can use a zillion photons over the bathroom scale and obtain no measurement whatsoever caused by "gravity".   If I say to you that my "weight" is 80kg on the bathroom scale, how you calculate the "gravity force", or "gravity acceleration" from that number?  You can't.  You need to know my mass and my altitude first, and then what planet I am.  So, it is not gravity you are measuring on that scale, it is my mass sliding through the space deformation caused by the planet.  You need my mass in order to calculate the sliding vector, without it, you have no "gravity force" indication.   

The same as when you measure the blacksmith's hammer "hitting force" on the iron.  The hammer has no force or energy whatsoever, it is the arm of the blacksmith that applies mechanical motion vector to the hammer against the iron.  You can not use or say "hammer hitting force", because there is none, even that you can in fact measure it.

[PhDawg]

Hello, I saw yesterday that THE_Earth_is_a_cube made a post and was recently banned. I have a genuine question. First, you claim that the Earth is the center of the universe, and that Earth moves upwards at 9.8m/s^2. If this is true, How would we have enough mass to support the orbit of every other planet and mass that goes around us? Take this opinion with a grain of salt, but I believe the Earth could resemble a torus. We have already discovered a mass like this, Llone 9UM. It is approximately 2.8 million light years away from Earth. It was taken from the apparent Hubble telescope. With all due respect with your theories, what could be a problem with this? Thank you very much.     

[QED]

Gravity is a force and arises from a potential. It can be generated, and this has been measured. It can be wasted - this has been measured too. Gravity certainly can be used - this is how we obtain energy in hydroelectric power plants.

Of course "gravity" can be generated, you can convert energy into mass, that mass will promote space deformation, thus, sliding vectors toward the center of such deformation, where space is less dense.   But that is it.

But sorry, you can not measure gravity, there is no over the counter equipment to do it, what you may be thinking is that we can measure the sliding vector of a mass towards another, using a common bathroom scale, that layman terms known as "weight".  That is not a gravity measurement device, sorry.  See, photons have no mass, but they have momentum, that can allow them to slide through the space deformation and change path.  You can use a zillion photons over the bathroom scale and obtain no measurement whatsoever caused by "gravity".   If I say to you that my "weight" is 80kg on the bathroom scale, how you calculate the "gravity force", or "gravity acceleration" from that number?  You can't.  You need to know my mass and my altitude first, and then what planet I am.  So, it is not gravity you are measuring on that scale, it is my mass sliding through the space deformation caused by the planet.  You need my mass in order to calculate the sliding vector, without it, you have no "gravity force" indication.   

The same as when you measure the blacksmith's hammer "hitting force" on the iron.  The hammer has no force or energy whatsoever, it is the arm of the blacksmith that applies mechanical motion vector to the hammer against the iron.  You can not use or say "hammer hitting force", because there is none, even that you can in fact measure it.

Sliding vector is a word you just made up.

There are other ways to generate gravity which we have measured.

Cavendish experiments can be made from over the counter equipment.

Weight is not a laymen term, it is a technical term in physics that is defined as the contact force between a massive object and the object which is applying a normal force against it.

Your weight is not 80kg, that is your mass. Your corresponding weight is about 800N. That is how you calculate it. It is the magnitude of the local gravitational force on you. The gravitational acceleration is found by taking your weight and divisions by your mass.

Look, all these things are taught in high school physics.

I’m trying to read your reply to give you credit for the correct things you’ve written. I am a little shocked, and not exaggerating here, that it doesn’t appear that anything you wrote is correct.

I have to wonder if you are trolling me right now. That is not sarcasm BTW, it is honest. Almost every FEer I speak with always says at least some things correctly.

[spherical]

Your weight is not 80kg, that is your mass. Your corresponding weight is about 800N. That is how you calculate it. It is the magnitude of the local gravitational force on you. The gravitational acceleration is found by taking your weight and divisions by your mass.

Again, gravity is not a force, it is a sliding vector (you will be reading more and more about it, pay attention).
By the way, in Brazil we started to learn physics right at the first semester of middle school, not high school.
Also, if you think gravity IS a force, you are first going against Albert Einstein (Nobel prize in physics), Carl Sagan, and several other astrophysicists, good luck on that.

Gravity is most accurately described by the general theory of relativity (proposed by Albert Einstein in 1915) which describes gravity not as a force, but as a consequence of the curvature of spacetime caused by the uneven distribution of mass. The most extreme example of this curvature of spacetime is a black hole, from which nothing—not even light—can escape once past the black hole's event horizon.[3] However, for most applications, gravity is well approximated by Newton's law of universal gravitation, which describes gravity as a force which causes any two bodies to be attracted to each other, with the force proportional to the product of their masses and inversely proportional to the square of the distance between them.

But we now understand that gravity as a force is only part of a more complex phenomenon described the theory of general relativity.  While general relativity is an elegant theory, it’s a radical departure from the idea of gravity as a force.  As Carl Sagan once said, “Extraordinary claims require extraordinary evidence,” and Einstein’s theory is a very extraordinary claim.  But it turns out there are several extraordinary experiments that confirm the curvature of space and time.

===

A body undergoing geodesic motion feels no forces acting upon itself. It is just following what it feels to be a "downward slope through spacetime" (this is how the bending affects the motion of an object). The particular geodesic an object wants to follow is dependent upon its velocity, but perhaps surprisingly, not its mass (unless it is massless, in which case its velocity is exactly the speed of light). There are no forces acting upon that body; we say this body is in freefall. Gravity is not acting as a force.

Dr Jolyon Bloomfield


===

Einstein’s discovery was based on a series of thought experiments. Consider an astronaut floating in space, away from any source of gravity, and that same astronaut free falling in a planet’s gravity. The similarity of both experiences is uncanny. The astronaut must glide or sit still until affected by an external force. If an astronaut falls or floats without any knowledge of his location, say, in an enclosed lift, he cannot distinguish whether the lift is floating in deep space or through a building on Earth. In both cases, he is essentially weightless. However, if he does not experience any force, why does a free-falling astronaut accelerate? In Newtonian mechanics, this is paradoxical, as it contradicts Newton’s second law of motion – the magnitude of acceleration is proportional to the applied external force.

Einstein suggested that objects aren’t pulled by massive objects, but rather pushed down by the space above them. According to General Relativity, matter warps the fabric of not only space but time as well, collectively known as the continuum of space-time. The fabric is like a grid of tightly strung rubber bands; when a massive object pushes and stretches them downward, the deformed rubber bands push objects under them. The theory implied that smaller objects weren’t pulled towards massive objects but were traveling on a downward slope, as the space in the latter’s vicinity was warped by its large mass. A free-falling body, therefore, follows the straightest possible path in space-time.

Einstein developed this theory on the assumption that the laws of physics must appear the same to every observer. This is also true for planets revolving around the Sun. Orbiting planets follow the shortest path around the Sun to minimize energy. This path is an ellipse, the most efficient path in the gravity well of the Sun… but what about the astronaut’s acceleration?

Einstein’s geodesic equations signify that acceleration is a product of curved space-time. His equation explains how curvature accelerates a falling object. In the absence of curvature, the body would move in a straight line with a constant velocity, unless this motion would be disrupted by an otherwise external force. However, the most interesting aspect of the equation is the absence of mass in its expression. The magnitude of acceleration is independent of the falling body, just as the equivalence principle would demand (if you drop a hammer and a feather on the surface of the moon, they would drop at the same time).

Akash Peshin
 
===

Albert Einstein, who won the Nobel Prize in Physics in 1921, contributed an alternate theory of gravity in the early 1900s. It was part of his famous General Theory of Relativity, and it offered a very different explanation from Newton's Law of Universal Gravitation. Einstein didn't believe gravity was a force at all; he said it was a distortion in the shape of space-time, otherwise known as "the fourth dimension" (see How Special Relativity Works to learn about space-time).

Basic physics states that if there are no external forces at work, an object will always travel in the straightest possible line. Accordingly, without an external force, two objects travelling along parallel paths will always remain parallel. They will never meet.

[QED]

Thank you for the detailed summary. I look forward to learning more from your expertise. If I may, might I ask some follow up questions? I think what you wrote is all a bit over my head, and I’m hoping you can clarify some items for me

1. Can you please provide a mathematical definition for sliding vector? Just an equation, no words.

2. It seems to me that general relativity and Lagrangian dynamics are not mutually exclusive. I can take Einstein’s field equations, and under the weak field limit, derive lagrangian dynamics for an object in a gravitational field. So even though GR is more widely applicable than classical dynamics, it appears that Einstein’s very own equations support a force interpretation for gravity in the weak field limit. Hence, I am not contradicting Einstein. Here is my question:

Beginning with Einstein’s field equations, can you please demonstrate that lagrangian dynamics are in fact incompatible in this limit? This would be a proof by contradiction, and would provide evidence for your claim.

3. Carl Sagan believed the earth was round. Do you?

4. Beginning with Einstein’s field equations, it can be shown that parallel lines can either stay parallel, converge, or diverge depending on a particular term in the equations. Do you know what this term is and what it’s geometrical interpretation is?

5. Einstein’s field equations are absent of mass/energy only in a particular limiting case. In this limiting case a specific object in the equations is negligible. Do you know what this object is?

I look forward to your replies

[spherical]

Of course I could answer your questions, with pleasure.
Problem is, I am not here to waste my precious time (and I am old, no much time to waste) teaching physics, mostly just to show my knowledge, this is not a competition, sorry, the time of my life to show a bigger stick is gone long ago.  My intention here is to clarify issues about flat earth.  It is clear that this discussion will go on and on, and it is not the scope of this forum, so research yourself about space deformity by mass and sliding vectors. 
Gravity is not a force - Albert Einstein said that, who am I to go against it?
I wonder if someone could demonstrate force without energy being applied.

For the ones wanting to learn about sliding vectors, I present you Einstein's Field Equation formula:

Sorry moderators, I stop here.
Cheers.

[QED]

Of course I could answer your questions, with pleasure.
Problem is, I am not here to waste my precious time (and I am old, no much time to waste) teaching physics, mostly just to show my knowledge, this is not a competition, sorry, the time of my life to show a bigger stick is gone long ago.  My intention here is to clarify issues about flat earth.  It is clear that this discussion will go on and on, and it is not the scope of this forum, so research yourself about space deformity by mass and sliding vectors. 
Gravity is not a force - Albert Einstein said that, who am I to go against it?
I wonder if someone could demonstrate force without energy being applied.

For the ones wanting to learn about sliding vectors, I present you Einstein's Field Equation formula:

Sorry moderators, I stop here.
Cheers.

Einstein also said “god does not play dice,” in objection to the destruction of determinism by quantum mechanics. He was wrong. In fact, it is quite clear the GR is either incomplete or incorrect. You will not find a professional physicist alive who fails to recognize this if prompted.

Readers: if interested, google a quantum theory of gravity, TOE, or grand unification.

I appreciate you at least posting “Einstein’s field equation formula,” but it is not singular, and in fact represents 16 coupled differential equations.

It is interesting that you have decided to stop “wasting your time” at the precise moment when I ask you basic questions regarding the knowledge you claim to have - but so far described it inaccurately. Especially when the answers you could have provided would have been to the educational benefit of readers.

Lastly, the field equations are not a good reference for those wishing to study sliding vectors. Clearly, you do not understand the role these objects play in GR.

Why don’t you leave the physics to me. I am happy to “waste my time” educating others. And it appears I may be better suited to provide it accurately.

Readers: if you are interested in learning about sliding vectors, then I recommend googling affine vector spaces, and then covariant and contravariant derivatives. Sliding vectors do not directly appear in Einstein’s field equations.

[Galieo005]

Some FE models introduce the concept of celestial gravitation where the heavenly bodies influence the weight of objects as they get higher.

I'm assuming that celestial gravitation is from the moon and sun. How far away are they on a FE model?

Also if the earth is accelerating upwards, what is making the sun and moon accelerate upwards too?

[markjo]

Some FE models introduce the concept of celestial gravitation where the heavenly bodies influence the weight of objects as they get higher.

I'm assuming that celestial gravitation is from the moon and sun. How far away are they on a FE model?

Estimates vary depending on the model, but about 3000 miles is the most common answer.

Also if the earth is accelerating upwards, what is making the sun and moon accelerate upwards too?

The same universal accelerator that accelerates the flat earth upwards is believed to accelerate the sun, moon and other celestial bodies at the same rate (hence the term "universal").

[EarthNotFlat]

I prove gravity real in this topic:
https://forum.tfes.org/index.php?topic=14694.0

[QED]

I prove gravity real in this topic:
https://forum.tfes.org/index.php?topic=14694.0

While I agree that your link establishes multiple points that FEers have so far not addressed, it is too ambitious to state that this “proves” the earth is round.

This is because your conclusion relies on an argument from ignorance fallacy: “it just doesn’t add up.”

One must demonstrate the impossibility rather than saying “I can’t think how it’s possible therefore it isn’t.”

I believe if you fleshed it out a bit more you’d have a very solid piece of argumentation there, as it already contains several strong points.