[TotesNotReptilian]

No, you see, if UA were truly UNIVERSAL then it would accelerate me even when I am no longer in contact with the earth, as it apparently accelerates the moon and sun and all the other not-attached-to-earth celestial objects we never catch up to.  But it does no such thing.

Oh, I see what you mean. Why does UA accelerate the earth and celestial bodies but not stuff on the earth? No idea. I guess that's just part of the "theory"...

[TotesNotReptilian]

If the FE is constantly accelerating upward there would be a displacement of air from in front of it.

Why would there be? The air would be pushed up by the ground, accelerating at the exact same rate as the ground, and moving at the exact same rate as the ground. The air would NOT be moving relative to the ground. Just like someone standing on the ground would not be moving relative to the ground. You can think of the air as "standing" on the ground.

This displacement of air should cause some measureable effect on a body, any body, within the realm of displacement.  This concept is readily seen in a vertical wind tunnel, the type any person can pay money to get into to approximate the experience of skydiving.  You contend that, because we don't have wings, humans are doomed to free fall through air.  Yet I can step into a vertical wind tunnel, with no special apparatus, and experience a situation in which I am not freely falling through air, simply through the interaction of displaced air acting on the surface area of my body.

Yes, terminal velocity is a thing, but I'm not sure what it has to do with UA. Reaching terminal velocity requires moving so fast relative to the air, that your vertical drag from the air cancels out the force of gravity (or UA). When Bob steps out of the airplane, he is initially NOT moving vertically relative to the air. Therefore, he will have no vertical drag, and will not be at terminal velocity. Therefore, he will fall.

You're concentrating on lift at the expense of the magical force that somehow gives us the perspective of gravity.

The "magical force" is just an upwards accelerating reference frame. Everything in that reference frame would appear to be accelerating down in comparison. The objects in this reference frame would appear to behave exactly as if there was a constant downward force acting on them. Like gravity.

[CableDawg]

If the FE is constantly accelerating upward there would be a displacement of air from in front of it.

Why would there be? The air would be pushed up by the ground, accelerating at the exact same rate as the ground, and moving at the exact same rate as the ground. The air would NOT be moving relative to the ground. Just like someone standing on the ground would not be moving relative to the ground. You can think of the air as "standing" on the ground.

So designers of things such as rockets, airplanes and automobiles don't have to do any calculations or take air displacement into account when designing their respective products since the air in front of each item is simply moving along with said item?

[CableDawg]

[/quote]

Yes, terminal velocity is a thing, but I'm not sure what it has to do with UA. Reaching terminal velocity requires moving so fast relative to the air, that your vertical drag from the air cancels out the force of gravity (or UA). When Bob steps out of the airplane, he is initially NOT moving vertically relative to the air. Therefore, he will have no vertical drag, and will not be at terminal velocity. Therefore, he will fall.

What the hell is this even supposed to mean?

If vertical drag cancels out the force of gravity then Bob would be floating in mid air.  You've already stated that Bob falls because he doesn't have wings.  Now your stating that, as long as he hits terminal velocity, he can cancel out the effects of gravity and float?

[CableDawg]

The "magical force" is just an upwards accelerating reference frame. Everything in that reference frame would appear to be accelerating down in comparison. The objects in this reference frame would appear to behave exactly as if there was a constant downward force acting on them. Like gravity.
[/quote]

This goes directly back to my initial statement.

"Once a person is free from the surface of the earth, through whatever means (but we'll go with an air plane here), they are free from the effects of gravity and are actually waiting for the earth to catch up to them, since there supposedly no gravity and only the effect of the earth rushing up."

[TotesNotReptilian]

If the FE is constantly accelerating upward there would be a displacement of air from in front of it.

Why would there be? The air would be pushed up by the ground, accelerating at the exact same rate as the ground, and moving at the exact same rate as the ground. The air would NOT be moving relative to the ground. Just like someone standing on the ground would not be moving relative to the ground. You can think of the air as "standing" on the ground.

So designers of things such as rockets, airplanes and automobiles don't have to do any calculations or take air displacement into account when designing their respective products since the air in front of each item is simply moving along with said item?

No. Airplanes/rockets/cars are moving through the air, not with the air. In the flat-earth UA scenario, the earth is not moving through the air. It is moving through space (presumably), and the air is being pushed along in front of the earth. Sometimes some kind of "firmament" is mentioned that keeps the air trapped next to the earth.

Yes, terminal velocity is a thing, but I'm not sure what it has to do with UA. Reaching terminal velocity requires moving so fast relative to the air, that your vertical drag from the air cancels out the force of gravity (or UA). When Bob steps out of the airplane, he is initially NOT moving vertically relative to the air. Therefore, he will have no vertical drag, and will not be at terminal velocity. Therefore, he will fall.

What the hell is this even supposed to mean?

If vertical drag cancels out the force of gravity then Bob would be floating in mid air.  You've already stated that Bob falls because he doesn't have wings.  Now your stating that, as long as he hits terminal velocity, he can cancel out the effects of gravity and float?

No, I didn't say he could float. I said he will stop accelerating. Acceleration = change in speed. Terminal velocity (speed) is the maximum speed at which someone will fall through the air, because if they go any faster, air resistance will push back stronger than gravity/UA pulls them down, which prevents them from accelerating further. They will continue moving downwards though.

The "magical force" is just an upwards accelerating reference frame. Everything in that reference frame would appear to be accelerating down in comparison. The objects in this reference frame would appear to behave exactly as if there was a constant downward force acting on them. Like gravity.

This goes directly back to my initial statement.

"Once a person is free from the surface of the earth, through whatever means (but we'll go with an air plane here), they are free from the effects of gravity and are actually waiting for the earth to catch up to them, since there supposedly no gravity and only the effect of the earth rushing up."

Assuming they step out of the plane, yes. If they are still in the plane, then the lift produced by the plane causes the sensation of gravity.

[CableDawg]

If the FE is constantly accelerating upward there would be a displacement of air from in front of it.

Why would there be? The air would be pushed up by the ground, accelerating at the exact same rate as the ground, and moving at the exact same rate as the ground. The air would NOT be moving relative to the ground. Just like someone standing on the ground would not be moving relative to the ground. You can think of the air as "standing" on the ground.

So designers of things such as rockets, airplanes and automobiles don't have to do any calculations or take air displacement into account when designing their respective products since the air in front of each item is simply moving along with said item?

No. Airplanes/rockets/cars are moving through the air, not with the air. In the flat-earth UA scenario, the earth is not moving through the air. It is moving through space (presumably), and the air is being pushed along in front of the earth. Sometimes some kind of "firmament" is mentioned that keeps the air trapped next to the earth.

Yes, terminal velocity is a thing, but I'm not sure what it has to do with UA. Reaching terminal velocity requires moving so fast relative to the air, that your vertical drag from the air cancels out the force of gravity (or UA). When Bob steps out of the airplane, he is initially NOT moving vertically relative to the air. Therefore, he will have no vertical drag, and will not be at terminal velocity. Therefore, he will fall.

What the hell is this even supposed to mean?

If vertical drag cancels out the force of gravity then Bob would be floating in mid air.  You've already stated that Bob falls because he doesn't have wings.  Now your stating that, as long as he hits terminal velocity, he can cancel out the effects of gravity and float?

No, I didn't say he could float. I said he will stop accelerating. Acceleration = change in speed. Terminal velocity (speed) is the maximum speed at which someone will fall through the air, because if they go any faster, air resistance will push back stronger than gravity/UA pulls them down, which prevents them from accelerating further. They will continue moving downwards though.

The "magical force" is just an upwards accelerating reference frame. Everything in that reference frame would appear to be accelerating down in comparison. The objects in this reference frame would appear to behave exactly as if there was a constant downward force acting on them. Like gravity.

This goes directly back to my initial statement.

"Once a person is free from the surface of the earth, through whatever means (but we'll go with an air plane here), they are free from the effects of gravity and are actually waiting for the earth to catch up to them, since there supposedly no gravity and only the effect of the earth rushing up."

Assuming they step out of the plane, yes. If they are still in the plane, then the lift produced by the plane causes the sensation of gravity.

Space is not empty.  There is still mass that has to be displaced for the FE to accelerate through it.

You certainly said nothing in regards to Bob's acceleration.  You stated that since he isn't at terminal velocity that he would fall.  Following the logic of this statement, as soon as he hits terminal velocity he will no longer fall and will in fact be floating.  You also stated that the drag created by Bob's body will cancel the effects of gravity which also lead to a condition of floating.

The lift of the plane causes the sensation of gravity?  If this were the case then every single movement command input by the pilot would be noticeably felt by the passengers.  Every instance of increase in altitude would be felt as more gravity.  Every instance in decrease in altitude would be felt as less gravity.  This is clearly not the case.

[TotesNotReptilian]

Space is not empty.  There is still mass that has to be displaced for the FE to accelerate through it.

I agree. Flat-earthers probably wouldn't though, considering they claim all space missions to be faked.

You certainly said nothing in regards to Bob's acceleration. 

Not explicitly. Sorry. I DID talk about gravity and drag, both of which are forces. Forces cause acceleration. No force = no acceleration. Look up Newton's laws.

You stated that since he isn't at terminal velocity that he would fall.  Following the logic of this statement, as soon as he hits terminal velocity he will no longer fall and will in fact be floating. 

No, that isn't good logic. (A) implies (B) does not imply (not A) implies (not B). That was a confusing statement, so I will give an example:

Getting hit by a rock causes pain. Does that mean you will never feel pain if you don't get hit by a rock? Of course not. There are other things that cause pain besides rocks.

You also stated that the drag created by Bob's body will cancel the effects of gravity which also lead to a condition of floating.

No, it will lead to the condition of not accelerating. There is a difference between speed and acceleration. You can have lots of speed without any acceleration. When you are at terminal velocity, you have lots of downward speed relative to the air, but no downward acceleration. You are moving fast, but you aren't increasing your speed anymore.

The lift of the plane causes the sensation of gravity?  If this were the case then every single movement command input by the pilot would be noticeably felt by the passengers.  Every instance of increase in altitude would be felt as more gravity.  Every instance in decrease in altitude would be felt as less gravity.  This is clearly not the case.

But it IS the case! Have you ever been on a plane before? When you are taking off, you feel like you are being pressed back into your seat. It feels like gravity increased. When turbulence causes the plane to drop a few feet, it feels like you are suddenly being lifted from your seat. It feels like gravity briefly decreased. Also, it feels like your lunch wants to crawl back out your esophagus.

This is the point I have been trying to make. An accelerating reference frame feels exactly the same as a force in the opposite direction for those inside the reference frame. An airplane at takeofff is accelerating upwards and forwards. To the passengers, it feels like a force is pushing them down and back into their seats.

[TheTruthIsOnHere]

My brain hurts trying to follow this illustration

Universal Acceleration seems like ridiculous band-aid.

There is another reason things go down and up, but I don't think it's a property endowed by virtue of mass.

How does Earth, which is basically God knows how many layers of different elements, fluid, solids, etc, have an exact center? How do we know this center is more dense than the surface? Why would things move exactly perpendicular time and time again, instead of when near a mountain, somewhat towards it.

Density explains which things go up or down, but not why. I am completely dissatisfied with Newtonian or "Einstein" hypothetical Gravity.

[BlueMoon]

My brain hurts trying to follow this illustration

Universal Acceleration seems like ridiculous band-aid.

There is another reason things go down and up, but I don't think it's a property endowed by virtue of mass.

How does Earth, which is basically God knows how many layers of different elements, fluid, solids, etc, have an exact center? How do we know this center is more dense than the surface? Why would things move exactly perpendicular time and time again, instead of when near a mountain, somewhat towards it.

Density explains which things go up or down, but not why. I am completely dissatisfied with Newtonian or "Einstein" hypothetical Gravity.

https://www.theflatearthsociety.org/forum/index.php?topic=66529.msg1774510#msg1774510


We know about the solid and liquid core because of how tremor waves from earthquakes are refracted by them, causing bands at a certain distances from the epicenter where no tremors are detected.  We also know about the inside of the earth because we use our seismographs to triangulate anomalies in the mantle.  That field is known as seismic tomography. 

[TotesNotReptilian]

My brain hurts trying to follow this illustration

Yeah, we definitely took the long way around, since I was trying to answer his specific objections.

Universal Acceleration seems like ridiculous band-aid.

I agree.

There is another reason things go down and up, but I don't think it's a property endowed by virtue of mass.

If you have a better theory, we would love to hear it. Until then, I'll stick with the tried and tested theory (gravity), thank you very much.

Why would things move exactly perpendicular time and time again, instead of when near a mountain, somewhat towards it.

Because as big as mountains are, they are tiny compared to the earth. Here's the great thing about gravity: we have actual equations capable of making actual predictions (as opposed to anything flat-earth related). I did a rough calculation of the strength of gravity from an 8000 meter tall mountain made of granite for someone standing 8000 meters away: 0.002 m/s². That's roughly 5000 times less than earth's gravity. If you have an instrument capable of detecting that tiny of a deflection, you are welcome to go and test it out!

[TheTruthIsOnHere]

There is another reason things go down and up, but I don't think it's a property endowed by virtue of mass.

If you have a better theory, we would love to hear it. Until then, I'll stick with the tried and tested theory (gravity), thank you very much.

Even Newton suggested it absurd that mass by virtue of being massive can exert a force through a vacuum. There is a medium. Modern physics is leaning towards everything being a field.

How can space (vacuum) be nothing? There has to be a medium by which the electromagnetic and nuclear forces are transferred. If space was nothing, including the space between an electron and the nucleus of an atom, everything would collapse.

So the effect might be the same -- things falling at 9.8m/s² until a terminal velocity due to atmospheric resistence. But I don't believe the Earth being big is the reason why.

Why would things move exactly perpendicular time and time again, instead of when near a mountain, somewhat towards it.

Because as big as mountains are, they are tiny compared to the earth. Here's the great thing about gravity: we have actual equations capable of making actual predictions (as opposed to anything flat-earth related). I did a rough calculation of the strength of gravity from an 8000 meter tall mountain made of granite for someone standing 8000 meters away: 0.002 m/s². That's roughly 5000 times less than earth's gravity. If you have an instrument capable of detecting that tiny of a deflection, you are welcome to go and test it out!
[/quote]

But why no anomaly? Is the Earth so perfectly homogeneous? Has it been proven to be so? Why would the center of mass be perfectly perpendicular to the core? Is it that much more dense and somehow more massive then all of the rest of the mass on Earth? Does the sloshing molten metal have a pull to it?

It doesn't make sense if a particle is attracted to every other particle inversely proportional to the distance that everything would perfectly want to be drawn to the center of the sphere.

Are you familiar with the Tamarack Mines Experiments?

[TotesNotReptilian]

Even Newton suggested it absurd that mass by virtue of being massive can exert a force through a vacuum. There is a medium. Modern physics is leaning towards everything being a field.

No offense, but I sincerely doubt you have a very thorough knowledge of QFT. I don't really know much about QFT either. A poor understanding of a very complicated theory is a recipe for bad conclusions. For example...

How can space (vacuum) be nothing? There has to be a medium by which the electromagnetic and nuclear forces are transferred. If space was nothing, including the space between an electron and the nucleus of an atom, everything would collapse.

So the effect might be the same -- things falling at 9.8m/s² until a terminal velocity due to atmospheric resistence. But I don't believe the Earth being big is the reason why.

As far as I know, your arguments against the existence of a true vacuum are correct, depending on how you define a "medium". However, I fail to see the connection between that and the implausibility of mass being the cause of gravity. In fact, gravity is very well defined as a classical field associated with a mass.

Disclaimer: As far as I know, gravity isn't well understood under QFT. Anyone who figures this out is pretty much guaranteed a Nobel prize. That doesn't mean that there is any evidence that gravity isn't associated with mass.

But why no anomaly? Is the Earth so perfectly homogeneous? Has it been proven to be so? Why would the center of mass be perfectly perpendicular to the core? Is it that much more dense and somehow more massive then all of the rest of the mass on Earth? Does the sloshing molten metal have a pull to it?

Of course there are anomalies. You can personally detect the anomalies with a cheap lab scale. Of course the earth isn't perfectly homogeneous. The earth is approximately spherically symmetric, but definitely NOT homogeneous.

How did it become spherically symmetric? Because gravity naturally lends itself to creating spherically symmetric objects. Everything tends to gravitate towards the densest part. Heavy elements tend to sink down towards the middle. Lighter stuff tends to float towards the top. This results in roughly spherically symmetric layers. Also, the stuff in the middle is under a lot of pressure from the stuff around it, making it more dense.

It doesn't make sense if a particle is attracted to every other particle inversely proportional to the distance that everything would perfectly want to be drawn to the center of the sphere.

How good are you at calculus? It makes perfect sense. See the shell theorem.

Are you familiar with the Tamarack Mines Experiments?

Thanks for this. I had vaguely heard of it, but never read any details. I can think of two explanations of the results off the top of my head:
1. Static charge built up on the bobs caused them to repulse each other.
2. Gravitational attraction to the edges of the mine shaft.

I have no idea if these explanations would survive the actual calculations, but they seem plausible. I would hope that the author of the paper took into account these possible explanations, but I don't see them mentioned in the paper.

Also, I still don't see how this is evidence that gravity isn't a function of mass. Interesting experiment nonetheless.

[Rounder]

Here is a paper about the Tamarak Mine experiment, with some theories.  Gravitational attraction to the shaft walls is considered and rejected, due to the small masses involved.  More likely suspects include voltage induced in over a mile of steel wire, Coriolis effect, and air currents.  No firm conclusions are drawn, and there seems to have never been another comparable experiment performed (deep straight holes in the ground, not that common)