141

Flat Earth Theory / Re: Does Flat Earth/UA reject the concept of spacetime?

« on: October 08, 2020, 09:01:07 PM »

You are confusing frames of reference, as used in GR, with reality.

He also says in the same paper that the g-field is caused and determined by the energy tensor of matter...he doesn't say that an accelerating earth causes the g-field.

I will add to this with another quote from Einstein.  You'll need to read the first part of the paper to get the the context, but the point he makes here is important.

I must warn the reader against a misconception suggested by these considerations.  A gravitational field exists for the man in the chest, despite the fact that there was no such field for the co-ordinate system first chosen.  We might also think that, regardless of the kind of gravitational field which may be present, we could always choose another reference body such that no gravitational field exists with reference to it.  This is by no means true for all gravitational fields, but only for those of a quite special form.  It is, for instance, impossible to choose a body of reference such that, as judged from it, the gravitational field of the earth (in its entirety) vanishes.

https://einsteinpapers.press.princeton.edu/vol6-trans/333

The wiki implies that an accelerating earth is the only logical explanation for the equality of gravitational and inertial mass.  It is misleading to use so heavily the work and reasoning of Einstein , when he came up with an entirely different explanation.   

142

Flat Earth Theory / Re: Does Flat Earth/UA reject the concept of spacetime?

« on: October 08, 2020, 05:27:43 PM »

In GR the surface of the earth is accelerating upwards through spacetime. It is Einstein's way of getting the upwardly accelerating Earth concept to work in RE, since experimental evidence and lack of inertial resistance shows that the Earth is accelerating upwards and that it is not an invisible phenomenon pulling bodies down to the Earth.

I get that in GR, gravity is not a force per se.  But it is still a process (for lack of a better term) which causes objects to be attracted to one another.  This process is caused by the warping of spacetime.

Gravity as a force and gravity as warping of spacetime may be two different things, but they have the same effect. In order to maintain a flat earth, it seems to me that both would have to be rejected.

And what experimental evidence is there that the earth is accelerating upwards? 

143

Flat Earth Theory / Does Flat Earth/UA reject the concept of spacetime?

« on: October 08, 2020, 04:18:35 PM »

The reason I ask is because UA rises and falls (pun intended) on the equivalence principle, but the equivalence principle logically leads (at least according to Einstein) to the gravitational and inertial effects of falling bodies as determined by spacetime...or as he calls it in the quote below the "g-field"

Inertia and gravity are phenomena identical in nature.  From this and from the special theory of relativity it follows necessarily that the symmetric "fundamental tensor" determines the metric properties of space, the inertial behavior of bodies in space, as well as the gravitational effects.  We shall call the state of space which is described by this fundamental tensor, the "g-field"

https://einsteinpapers.press.princeton.edu/vol7-trans/49?highlightText=metric

144

Flat Earth Theory / Re: Clarifications on UA

« on: October 07, 2020, 01:52:27 PM »

It is an astounding coincidence that inertia, an entirely different properly of mass, should slow all bodies in Earth's gravity to exactly the same rate of acceleration.

Inertia is not a different property of mass.  In 1918, Einstein restated the Equivalence Principle as

Inertia and gravity are phenomena identical in nature.  From this and from the special theory of relativity it follows necessarily that the symmetric "fundamental tensor" determines the metric properties of space, the inertial behavior of bodies in space, as well as the gravitational effects.  We shall call the state of space which is described by this fundamental tensor, the "g-field"

https://einsteinpapers.press.princeton.edu/vol7-trans/49?highlightText=metric

It isn't an objects mass that determines how it moves, it is the g-field.  So it is no coincidence that all masses will move through the same g-field in the same way. 

Can we have a quote and a source for these assertions that gravitational mass never changes anywhere? The assertion that "gravitational mass" never changes, and is the same on Earth, on Jupiter, and on the Moon—always unchanging—is something that I would like to request a source on, as it goes against everything I have learned on the subject. Clearly, there is no gravitational mass in weightless space, so it cannot be unchanging.

You are confusing weight and mass.

While the weight of an object varies in proportion to the strength of the gravitational field, its mass is constant, as long as no energy or matter is added to the object.[3] For example, although a satellite in orbit (essentially a free-fall) is "weightless", it still retains its mass and inertia

.

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

145

Flat Earth Theory / Re: Zetetic method vs UA

« on: October 06, 2020, 01:55:29 PM »

So he didn't so much "solve" the coincidence as depend on it further, working it into the fundamental fabric of the "theory".

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GR, at its core is an explanation as to why inertial and gravitational mass are indistinguishable.  It's because they are the same thing. In a Nature article in 1921, AE said

Can gravitation and inertia be identical?  The question leads directly to the General Theory of Relativity.

In 1918, AE restated the equivalence principle as

" Inertia and gravity are phenomena identical in nature.  From this and from the special theory of relativity, it follows necessarily that the symmetric "fundamental tensor" determines the metric properties of space, the inertial behavior of bodies in this space, as well as the gravitational effects.  We shall call the state of space which is described by this fundamental tensor the "G field".

In other words, the reason bodies fall independent of their mass is because mass is not what determines their behavior.  The "G field" does.

This is not so different from the UA explanation, which is the acceleration of the earth that determines how things fall.  The difference is that Einstein's g-field has been experimentally verified as the the curvature of spacetime, and the acceleration of earth has not.

146

Flat Earth Theory / Re: Where is the Sun?

« on: October 05, 2020, 07:48:37 PM »

How many of those space agencies can really operate as fully independent space agencies?

https://www.planetary.org/explore/the-planetary-report/australia-space-program.html

  “ The fact that so many countries seem to want a space program implies an inherent value to exploring space, but what is it? Last year, Australia became the latest country to announce the formation of its own space agency. The process took a significant step forward in March with a new report recommending goals and focus for its space agency.

The report also provides insight about why Australia sees space as a valuable enterprise. The report highlights several areas where the country could leapfrog others by strategically investing in specific capabilities (for example, artificial intelligence or quantum computing) and sets out a goal of tripling the size of the Australian space industry by 2030. One of the keys to succeeding in this new effort, the report declares, will be international partnerships.

International partnerships provide the means for countries to participate in the exploration of space without having to create expensive, enabling infrastructure from the ground up. They can leverage the space capabilities of other nations while providing unique contributions to the benefit of their own industry and scientific base. This is the opposite of a zero-sum, competitive mentality of international relations; a rising rocket lifts all spacecraft, if you will. The European Space Agency’s very existence relies on this model. Its BepiColombo mission—as you will read in this issue—includes contributions from 13 European member states, the United States, and Japan. This coalition of nations is deeply invested in the success of the mission, spreading out the cost and also the political support. ”

NASA is encouraged to help other countries do space activities.

https://spacepolicyonline.com/topics/international-space-activities/

NASA AND INTERNATIONAL COOPERATION IN SPACE

  “ International cooperation has been a hallmark of NASA’s programs throughout its history. The law that created NASA, the 1958 National Aeronautics and Space Act, included Section 205 that encouraged NASA to cooperate with other countries. A 2014 report by NASA’s Office of International and Interagency Relations states that NASA has signed over 3,000 international agreements since its inception. The report, Global Reach: A View of NASA’s International Cooperation, lists international cooperative projects ongoing at NASA at the time of publication. ”

Signing 3K international agreements, sharing technology and encouraging and cooperating with other countries (even otherwise hostile countries) doesn't seem to be a very effective way to "militarily dominate space".

What is even the point of falsely claiming to dominate something that either doesn't even exist or is technologically impossible?

Makes as much since as Facebook spending billions of dollars just to be able to proclaim it dominates social media before the internet existed.

147

Flat Earth Theory / Re: Zetetic method vs UA

« on: October 04, 2020, 09:51:24 PM »

Gravity is not in any way an acceleration.

according to the accelerometer on my phone it is.  Interesting experiment I just did.  The app I have allows you to ignore or include gravity.  When I used gravity and place the phone face up on the floor, it showed -1g.  When I ignored gravity, it showed 0g.

Wondering how UA would account for those results?

the equivalence principle is preposterous coincidence as a lynch pin in mythology being disingenuously/erroneously presented as science.

Einstein solved the coincidence of the equality of inertial mass and gravitational mass with GR by unifying inertia and gravity into one field, like the electromagnetic field.

148

Flat Earth Theory / Re: Zetetic method vs UA

« on: October 04, 2020, 08:45:57 PM »

Obviously not defending UA, but Tom's explanation is consistent with the UA model.   If the ground was indeed moving up pushing the air with it then an object of more mass would be more "work" than one of less mass

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I get that.  I was just pointing out that something can't be at "zero acceleration" and be "pushed up" at the same time.  Zero acceleration means no force is applied...when something is being "pushed up" there is a force.

149

Flat Earth Theory / Re: Zetetic method vs UA

« on: October 04, 2020, 05:46:36 AM »

They are not slowing down, they are not moving. They are being pushed upwards by the air.

How can they be "not moving" and be "pushed upwards" at the same time?  If something is being pushed, it's moving.   The only way it wouldn't be moving is if it is being pulled at the same time, with the same force, in the same opposite direction.

150

Flat Earth Theory / Re: Zetetic method vs UA

« on: October 04, 2020, 05:26:14 AM »

The Earth is accelerating upwards. The air is on top of the Earth. When you jump out of an airplane you are inert in space, weightless. The Earth pushes up the air into you. You feel air blowing up against your face and see the Earth accelerating up towards you.

I get that.  My point is that air resistance can't be the reason the ground makes contact with a less massive object before it makes contact with a more massive object.  Neither object is moving.  As you say, both are inert, so what does air resistance have to do with anything?  It isn't "slowing down" a more massive object if it isn't moving in the first place.

If a bowling ball and a feather are both inert in the air at the same elevation, the earth will reach both of them at the same time.  Air resistance would have no effect.

EDIT:  To be more clear.  If UA is pushing the feather up, then it is being accelerated...it isn't inert.

151

Flat Earth Theory / Re: Zetetic method vs UA

« on: October 04, 2020, 04:37:52 AM »

When you jump out you will transition from being accelerated upwards to zero acceleration (ignoring air resistance), as you are no longer connected to the floor of the plane

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How can there be air resistance when there is no acceleration?  If you aren’t being accelerated in any direction there is nothing to resist against.

152

Flat Earth Theory / Re: Gravity - measurement and applications

« on: September 10, 2020, 12:19:28 AM »

the equivalency principle is really only valid for local reference frames and cannot account for these local variations.

Its also only valid for objects in free fall.  Not everything that falls is free fall.

153

Flat Earth Theory / Re: Center of gravity of objects on a flat earth

« on: August 28, 2020, 11:30:43 PM »

Even in a vacuum, the  acceleration is going to produce an upward force on the fulcrum through a normal force exerted by the ground  Since the force does not occur at the center of mass of the seesaw, a torque is exerted .This will cause the seesaw to rotate exactly as it would in a gravitational field

Normal force is only as strong as the accelerating force.  They cancel each other out. Technically normal force causes acceleration, but since net force is zero, there is no motion.  If you've got an acceleratormeter n your phone, turn it on and place it on a table.  It will show acceleration equal to gravity.  Its measuring the normal force, but your phone isn't moving.

It’s been 100 years since The Equivalence Principle was proposed.  If there was a hypothetical experiment that would have violated it, I think someone would have figured it out by now.

Equivalence principle only applies to freely falling objects, not to mention limited space and time.

Edit:  Reading through the above threads, with the seesaw/teetertotter example, we need to consider torque.  Simply looking at the forces doesn't tell the whole story, because the seesaw system as a whole its no longer a rigid body.  As mentioned above, the degree to which the seesaw rotates, is going to depend not just on the mass balance at either end, but where the fulcrum is placed.  This is a separate issue from the CoM, as we can make a simplification that the mass of the board connecting the children and the  mass and that of the fulcrum are small in comparison to the weight of the two children.  But if we shift the position of the fulcrum, it changes the behavior without affecting the CoM or the forces involved.

Direction of rotation is always in the direction of the strongest torque.  Torque is T=F*D.  If the fulcrum is in the middle and the distance is the same, rotation will be in the direction with the greatest force. With 75N of upward force on one side and 50N of upward force on the other side, rotation will up, towards the side with 75N.

154

Flat Earth Theory / Re: Center of gravity of objects on a flat earth

« on: August 27, 2020, 09:43:39 PM »

You need to ask yourself how 100kg-kid is "... supported above the ground".  He isn't suspended by levitation, he's only there because he's an integral part of a rigid ASSEMBLY comprising him, the 50kg-kid, and a beam, all attached to the planet by a pivot.  We assume that the beam itself is symmetrical and its mass is evenly distributed, so the COM of the ASSEMBLY is to the right of the pivot, because that's the end the 100kg-kid is sitting.   

If the planet accelerated up at 9.81 m/s/s, that force is going to be felt at the pivot of the ASSEMBLY.  The inertia of the ASSEMBLY acts at its COM which to the right of the upward accelerating force.  The 2 forces form a couple which rotates the ASSEMBLY clockwise until the planet hits 100kg-kid's butt, at which time the accelerating force is now distributed to both sides of the COM, via the pivot and his butt. 

Stop thinking of him in isolation.  He's just a part of something bigger. 

And have you noticed I've stopped calling him fat-kid.

I didn't fully explain myself, my bad.

Assume we have a seesaw with the fulcrum in the middle with 100N downward force on the left and 50N downward force on the right (IOW, gravity).  It will rotate counter clockwise.

Now reverse the direction of the force (universal acceleration), with 100N on the left upward force and 50N on the right upward force.  It will rotate clockwise.  The heavier side will be suspended in the air, instead of falling to the ground.

My point was that inertia will slow down the rotation, maybe even stop it, but it won't reverse the rotation from clockwise to counterclockwise.

155

Flat Earth Theory / Re: Center of gravity of objects on a flat earth

« on: August 26, 2020, 04:04:03 AM »

Because of the laws of inertia. When I hit the gas in my car i'm pulled back into the seat of my car, opposite the direction of acceleration.

You will only be pulled back with a force that is equal the acceleration.  Inertial forces are opposite and equal.

The concept of universal acceleration with inertial forces "pinning" you down works fine as long as you are already on the ground, but not if you are supported above the ground.

If 100kg kid is on one side, he would be accelerated up with a force of 980N, with an inertial force resisting with same amount of force, 980N. The inertial force will "pin" him to the seat of the teeter totter to keep him from levitating, for lack of a better word, but it wont push the seat down to the ground if it is above ground.

980N up and 980N down means zero net force and zero net force means no movement for an stationary object.

156

Flat Earth Theory / Re: Center of gravity of objects on a flat earth

« on: August 22, 2020, 05:11:11 AM »

if an object being pulled down by acceleration is supported by something in which is COM is not over the support it topples over.

You can’t be pulled down by acceleration that is pushing up.

As was pointed out earlier in the thread…F=M*A, which is true but not the complete picture.
Force and acceleration are vectors and have both direction and magnitude.  Simply assigning a magnitude to a force doesn’t tell you squat about how the force is affecting something.  Is it moving it up? Is it moving it down? Sideways? Crushing it?

In order to answer those questions, you have to assign a direction to the acceleration. Assign upward (or positive) direction to the acceleration, as you would have on a flat earth, you end up with an upward force. Assign a downward (or negative direction), as you would have with gravity, you end up with a downward force.  How is an upward force pulling something down?

The bottom line is that when something is balanced, is simply means that gravity is acting equally on all parts of an object.  By that definition, I don’t see how anything could ever be unbalanced on a flat earth, considering that the acceleration force is constantly and consistently accelerating everything with the same amount of force.  Even if that weren’t the case, I don’t see how it could cause something to fall “down”, when the force itself is up. Any downward force that would come from a supported object would be the normal force, and would it would only be equal to the upward force.  No net force, means no movement in any direction. 

157

Flat Earth Theory / Re: Center of gravity of objects on a flat earth

« on: August 20, 2020, 11:37:23 PM »

It doesn't matter whether the acceleration is due to gravity, ball hit by a bat, bullet in a gun, or something on the floor of an aircraft pulling "g".  As long as the accelerating force is distributed around the Centre of Mass (C of M) it's stable.

But what if it isn't distributed around the COM?  That's kind of my point.  The COM is where gravity will exert the most pull, because that is where the object's mass is concentrated.  But from what I can tell from the wiki, the "accelerator force" must be evenly distributed. It doesn't vary according to position.

If two kids are of equal weight on a teeter totter with the pivot in the middle, it will balance.  But if you move the pivot, you shift the COM and one side increases in mass.  Greater mass means greater gravitational pull.  Gravity is pulling harder on one side than on the other and causes the more massive side to fall. If the accelerator force is what causes it to fall, then the accelerator force would have to be greater on one side than on the other.

There's nothing in the wiki to suggest that greater mass means greater accelerator force and I don't even know how that would work.  The ground on one side would have to be accelerating at a different rate than the other.

158

Flat Earth Theory / Re: Center of gravity of objects on a flat earth

« on: August 19, 2020, 11:04:45 PM »

In both the RE and the FE models someone who is accelerating upward would be unable to tell the difference from this upward acceleration and being inside of a gravitational field. Here's a video explaining this.

I understand the equivalence principle and see how it is a good alternate theory of gravity for objects in free fall.  But I don't think it applies to my question.

The ground can't move up to meet something that's already on the ground when it falls.  If you're already standing on the ground and lean over far enough, you lose your balance and fall. Technically, you rotate. The ground doesn't move up to meet you if your feet never leave the ground.  IF your feet are still in contact with the ground, your whole body should continue to move up with the ground.

And even if your feet do leave the ground, the equivalence principle still doesn't explain why lose your balance in the first place.  The mainstream explanation is that your center of gravity is no longer directly over your support and gravity will act on the part of your body that has the most mass.  My assumption is that flat earth wouldn't recognize an object's center of gravity as being a real thing.

Think of a simple balance scale that is resting on the ground.  The ground is accelerating up, taking the scale with it.  Put a heavy rock on one side and it will "fall".  It might not touch the ground but it still falls, all the while the scale as a whole is also moving up with the ground.

Or a teeter totter.  If a heavier kid is on one side, that side will fall, maybe touching the ground or not, but the whole teeter totter is rising at the same rate, so why would one side fall and not the other?

159

Flat Earth Theory / Center of gravity of objects on a flat earth

« on: August 19, 2020, 07:09:02 PM »

I’ve been reading about universal acceleration in the wiki and it’s a good alternative explanation for gravity for objects that are free falling.  But not everything that falls is in free fall.  Things that are already on the ground or supported in some way topple over, or fall, or drop all the time. According to conventional physics, it is because an objects center of gravity shifts or isn’t low enough to keep it upright.  Something with a low center of gravity is much more stable than something with a higher center of gravity and is less likely to fall.

Is there an FE explanation for why somethings are more stable than others since the conventional “center of gravity” concept wouldn’t apply (I’m assuming)?  What would cause something to be balanced or unbalanced on the flat earth?