Flat Earth No Dome No Stars

Jing

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but I do not agree it is a monumental conspiracy that every astrologist and scientist across the entire world is in on
So are you saying pufa are good for you because every doctor,scientist teacher,cook say pufa are good for you they couldn't all be lying right? They just believe what what are told .
 

Jing

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It doesn't matter what you call it. There is a force, or law, mandating that objects fall to the earth.
No there isn't a force making objects fall to the ground, it's the medium that determines if something falls or rises that's the reason why things can float in water but fall to the ground in air it's the reason helium balloon will rise because it is less dense than the surrounding medium we can all do experiments to prove this is true. What experiments can you do that prove it is a force pulling the object to the floor?
 

InChristAlone

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Can you prove what you just said on a spinning ball earth?
This is one of the easiest to prove: Is the earth a spinning round ball?

"


Foucault pendulum at the Panthéon in Paris, 1851.
220 feet long, 62 pound bob.
foucault_pendulum_1851.jpg
The Foucault Pendulum. There are many evidences of the earth's rotation. The one most people have heard about is the Foucault Pendulum (Léon Foucault, 1819-1868), a pendulum swinging slowly on a very long wire from a fixed support. As the earth rotates underneath the pendulum, its plane of swing relative to the room it is in slowly precesses at a constant rate, easily observed. Science museums around the world have such pendulums, and some university physics buildings do also. Pendulums at different latitudes have different precession rates, and the data confirms not only the earth's rotation, but the fact that it is round.
Gyroscopes. A spinning wheel, mounted so that it can freely turn in any direction with respect to the earth, will maintain spinning about a fixed axis as the earth turns underneath. Its behavior as a function of latitude is clear evidence that the earth is round and that it rotates. It can also tell us the earth's rotation period even if the gyroscope were in a closed room.

As light propagates down the telescope,
the telescope moves, requiring a tilt of the telescope.
The apparent angle of the star φ differs from its true angle θ.
[Not to scale; the angle is very much smaller.]
From The Wikipedia.
Stellar_Aberration.jpg

Stellar aberration. The earth's motion relative to the stars is measurable. James Bradley (1693-1762) demonstrated this, reporting his results in 1728. The earth rotates on its axis and revolves around the sun. Incoming light from stars passing into a telescope has finite speed, so from the time it enters a telescope objective to the time it reaches the eyepiece, the telescope has moved due to the motion of the earth. So the telescope must be aimed slightly forward (in the direction of its motion) to compensate for this. Measurement of this tilt angle confirms what was already known about the motion of the earth. This size of this effect is dependent on latitude, so it also provides evidence that the earth is round.
Some flat-earthers try to explain this as an atmospheric refraction effect. They conveniently overlook the fact that stellar aberration is biased in direction, because of the earth's rotation. Atmospheric refraction would be seen in all directions.

Schematic of the Sagnac interferometer.
From the Wikipedia.
sagnac_interferometer.svg.png

The Sagnac effect. The Sagnac interferometer sends two light beams around a closed path in opposite directions. The two beams then pass through a partially silvered mirror and then are recombined, forming an interference pattern. Rotation of the entire device is revealed by the shift of the interference pattern of the two beams. This effect is the basis of laser gyroscopes now often used to replace mechanical gyroscopes. They also reveal the earth's shape and rotation. The Sagnac interferometer and the mechanical gyroscope work on entirely different principles, but they both reveal the rotation of the earth, and give the same result for its rotation speed.
Atmospheric cyclones and anticyclones, demonstrate earth's rotation and the direction of that rotation. These are examples of Coriolis effects. The fact that they have opposite sense of rotation in the northern and southern hemispheres is evidence of an antisymmetry about the equator. This would not be the case even on a spinning flat disk earth. Ocean currents have the same sort of symmetry, though these depend on several influences, including winds, and water density. These also support the fact of earth's rotation, but the interpretation of the evidence is complex.*

The Compton tube apparatus.
compton-tube.gif

The Compton tube. Physicist Arthur Holly Compton (1892-1962) devised a neat way to demonstrate earth's rotation in 1913. It is called the "Compton tube". It is seldom mentioned in textbooks. It uses a large 1 meter diameter glass torus filled with liquid having small particles in suspension. It is aligned in a plane east-west (parallel to the equator) and allowed to stabilze for a day or more, then it is quickly rotated 180 degrees about its diameter. The suspended particles are observed with a microscope and for a few seconds they rotate with respect to the tube, the motion damping out in about 20 seconds. This motion occurs because the liquid and the particles were initially moving with the tube around the earth's axis. After the tube flips, the liquid and the particles, are now moving in the opposite direction inside it. Their speed can be observed with the microscope. This device not only indicates the direction of North, but also shows which direction the earth rotates. I find only one brief mention of this on the Internet. See: Science World, Compton tube. Compton proposed this as an inexpensive and practical method for demonstrating the earth's rotation in a school laboratory.*
Long distance projectiles and unguided missiles must be launched at a calculated angle and direction if they are to hit their targets. This requires taking the earth's rotation into account in the calculations. They must also use the fact of the earth's surface curvature.*
During a World War I naval engagement near the Falkland Islands British gunners were puzzled why their precisely aimed guns were falling to the left of the German ships. Their guns had been corrected for the earth's rotation, but the correction was for the Northern hemisphere. The Falkland islands happen to be in the Southern hemisphere. So the guns failed to correctly account for the earth's rotation. Who says it doesn't matter whether you accept the rotation of the earth?
Launching earth satellites into orbit takes advantage of the earth's rotation. With the exception of satellites intended for polar orbits, they are launched heading eastward. This requires the least fuel. If launched westward they would need to gain as much speed as the earth (in the wrong direction) plus the additional speed to achieve orbital speed. Satellites in low orbit must reach speeds of about 17,500 mph. The launch rocket on the launching pad already has velocity toward the East due to the Earth's rotation. Launches near the equator gain 1,000 mph from Earth's rotation.*
The Doppler effect is the shift of frequency of light (or any electromagnetic radiation) due to the relative velocity of source and receiver. If source and receiver are moving toward each other the frequency rises; if they are moving apart the frequency decreases. We now have orbiting earth satellites that can image the earth with Doppler radar, primarily for gathering atmospheric data. This data confirms (a) the round shape of the earth, and (b) its rotation. We even left a cube corner light reflector on the moon that allows us to send a beam of laser light to the moon, which directly reflects back to the earth station that originated it. This can accurately measure the distance to the moon as it changes due to the moon's orbital eccentricity. This can even measure the change in this distance due to the earth's rotation relative to the moon, confirming the round shape of the earth. Similar confirmation of the earth's shape and rotation comes from global positioning systems (GPS).*
Falling bodies. A stone dropped down a deep vertical mine shaft is deflected slightly eastward. This is because its velocity at the earth's surface is greater than the velocity of the earth at the bottom of the shaft, which is nearer earth's center. This is true in either hemisphere of earth, but the amount of deflection depends on latitude, being greatest at the equator and reaching zero at the poles. The deflection also happens with a stone dropped from a high tower. This effect is also clear evidence of the sphericity of earth.*
In fact this experiment has a long history. Some early philosophers denied the rotation of the earth. They argued that if it were rotating, a stone dropped from the mast of a ship would not fall to a point on deck directly below, but would fall behind the mast. Experiment proved otherwise, because, as Galileo argued, the stone at the top of the mast was initially moving just as fast as the deck below, and retains that speed as it falls. So he concluded that even on land, if the earth moves, a stone dropped from a high tower falls to a point directly below. So the earth's rotation, he said, doesn't affect motion of objects on earth.
But he was only approximately correct. There's more to this story. Galileo had not considered the fact that on a round rotating earth the top of a high tower actually moves faster than the ground at the base of the tower, due to it being farther from the center of the earth. So the stone at the top is also moving faster than the ground below, and retains this velocity all the way down. So it gets ahead of the ground and falls to the east of the point just below, opposite to the prediction of the flat earthers. The effect is small, because the difference in velocity at top and bottom is so small, but it is measurable with precision instruments. Flat earthers predicted the ball would fall beind the mast if the earth were moving, but it actually falls ahead of the mast. So the flat earther's experiment actually is another evidence for a round, rotating earth.*
Atomic Clocks. Standards of length and time are now based on the microwave radiation from atomic energy level transitions. Supercooled cesium-133 has been used for this for several decades. Now atoms of strontium-87 and ytterbium-171 offer a threefold increase in the precision in such measurements. Einstein's special relativity theory predicts that clocks suffer time dilation when they are moving, and this has been experimentally conclusively confirmed. Now, with strontium-87 clocks we can even compare the difference in speed between networked clocks located at different places on earth. In 2017 Pacóme Deva of the Paris Observatory and his colleagues did this, using optical fiber links between London and Paris, and one between Paris and Braunschweig, Germany. While this was reported in the press as a test of special relativity, it also serves as a measure of earth's axial rotation and its sphericity, since the cities being compared are at different latitudes, and therefore different distances, from the earth's axis, and have a different velocity due to that fact. [New Scientist, 25 March 2017, p. 11,] *​
 

Perry Staltic

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No there isn't a force making objects fall to the ground, it's the medium that determines if something falls or rises that's the reason why things can float in water but fall to the ground in air it's the reason helium balloon will rise because it is less dense than the surrounding medium we can all do experiments to prove this is true. What experiments can you do that prove it is a force pulling the object to the floor?

A helium balloon doesn't rise forever; it stops at some point when the gravitational and buoyant forces are equal. Otherwise it would continue into space because of momentum. Gravity keeps it from doing that.

Furthermore things don't rise because they are less dense than their surroundings. There has to be a buoyant force lifting them up, and that buoyant force is based on gravity pulling heavier molecules down, which lift less dense objects up.
 

yerrag

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I am glad you are no longer arguing for flat earth, but I thought you argued it is perfectly flat on top of the sphere? Which wouldn't make sense given the dip of the horizon. As far as the laser light experiment, that was just a misunderstanding of how laser beams work.

"A laser beam diverges, and will not be focused to a point very far. A laser emitter with the beam divergence of 1 mRad will have a beamwidth of 10 meters over 10 km. Contrary to what they expected, a laser beam will not stay on the constant height from the surface.

A laser beam is a form of light, and just like every other light, they are affected by atmospheric refraction. In most cases, atmospheric refraction will bend the laser to follow Earth’s curvature up to a point. Some of the laser beams will skirt just above the surface where atmospheric refraction is the highest."

I do think flat earth theories are ancient ignorant mentalities due to distrust of science. I also agreed with him about not using the straw man that if scientists believe in climate change and other terrible theories that means all of science cannot be trusted.

No, it isn't a straw man as I refer to the attitude Staltic hold, and I use climate science as an example of how consensus can take the place of real experimental proof to establish that climate change is caused by man's activities. How could he deride and insult someone as being from the dark ages and yet be oblivious that we are far from being enlightened when chicanery is used to keep people in the dark by the the high priests of science.

And you stand with Staltic on his high fallutin attitude?

As far as lasers go, I don't know you know so much about how they bend and follow the curve of water surfaces such that over long distances they would just follow the contour of the curvature of the earth and then hit right smack an object that is at the linen of sight at the same height as the source of the laser light.

I'm not a scientist and I probably should not engage you in technical matters that I underestimated you on. But if that is your way of disproving the Brazilian scientists, then I should defer to your technical acumen in demolishing the proof made by the Brazilian scientists, who may not know as much as you do about lasers.

And lastly, it bears repeating that the reason I say that the earth may be magnitudes larger is because the lack of a noticeable curvature makes earth appear flat. I did not literally say this, but it was implied but I was mistaken in thinking someone like you would pick up on it. Maybe you did, but you just had to use that against me. Touché.
 

Jing

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A helium balloon doesn't rise forever; it stops at some point when the gravitational and buoyant forces are equal. Otherwise it would continue into space because of momentum. Gravity keeps it from doing that.

Furthermore things don't rise because they are less dense than their surroundings. There has to be a buoyant force lifting them up, and that buoyant force is based on gravity pulling heavier molecules down, which lift less dense objects up.
A helium balloon won't rise forever because it eventually reaches a point where it is just resting on top of the air like how something just floats on top of water.

No the thing lifting them up is the medium surrounding them not some imaginary forces. Again we can actually do experiments to prove this is the case unlike you who is not providing any experiments to prove gravity is causing the objects to fall..... get a tank of water hold an apple at the bottom of the water now let go , watch it rise to the top of the water because the water has pushed it upwards because the apple is less dense than water, now hold the apple in air above the ground now drop it watch it fall to the ground it fell because it is more dense than the air surrounding it.. simple easy experiment to show it depends on the surrounding medium why things fall or rise. If gravity is pulling all objects to the ground then the apple shouldn't float on water but be at the bottom of the tank. Now do you have any experiments to prove your point that gravity makes objects fall?
 

Perry Staltic

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A helium balloon won't rise forever because it eventually reaches a point where it is just resting on top of the air like how something just floats on top of water.

No the thing lifting them up is the medium surrounding them not some imaginary forces. Again we can actually do experiments to prove this is the case unlike you who is not providing any experiments to prove gravity is causing the objects to fall..... get a tank of water hold an apple at the bottom of the water now let go , watch it rise to the top of the water because the water has pushed it upwards because the apple is less dense than water, now hold the apple in air above the ground now drop it watch it fall to the ground it fell because it is more dense than the air surrounding it.. simple easy experiment to show it depends on the surrounding medium why things fall or rise. If gravity is pulling all objects to the ground then the apple shouldn't float on water but be at the bottom of the tank. Now do you have any experiments to prove your point that gravity makes objects fall?

Water of itself has no ability (power) of itself to be able to move the apple upwards. The force of water being pulled down by gravity displaces the apple upwards due to a greater gravitational force on the denser water and and a lesser force on the apple..
 

Jing

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Water of itself has no ability (power) of itself to be able to move the apple upwards. The force of water being pulled down by gravity displaces the apple upwards due to a greater gravitational force on the denser water and and a lesser force on the apple..
No what is happening is the apple is less dense than the water so the apple can't hold the water down so it gets pushed upwards , but take say a rock and it will fall to the bottom of the tank because it can hold the water down. It's easy to test yourself if you record it and watch it in slow motion it's easy to see the water pushing the object upwards of course the water doesn't have a mind of its own thinking to push upwards lol well I've given you experiments how about you give me an experiment to prove its the force of gravity pulling objects down? Otherwise you saying gravity did it is just the same as a religious person saying God did it.

I guess an easier way to understand it could be with a spring let's say you have a spring and you are strong enough to hold the spring down with your finger this is the same as a rock falling to the bottom of the tank because it is dense enough to hold the water down, now if you aren't strong enough to hold the spring down then it will spring upwards and push your finger upwards this is the same as the water pushing the apple upwards because the apple isn't dense enough to hold the water down
 

InChristAlone

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No, it isn't a straw man as I refer to the attitude Staltic hold, and I use climate science as an example of how consensus can take the place of real experimental proof to establish that climate change is caused by man's activities. How could he deride and insult someone as being from the dark ages and yet be oblivious that we are far from being enlightened when chicanery is used to keep people in the dark by the the high priests of science.

And you stand with Staltic on his high fallutin attitude?

As far as lasers go, I don't know you know so much about how they bend and follow the curve of water surfaces such that over long distances they would just follow the contour of the curvature of the earth and then hit right smack an object that is at the linen of sight at the same height as the source of the laser light.

I'm not a scientist and I probably should not engage you in technical matters that I underestimated you on. But if that is your way of disproving the Brazilian scientists, then I should defer to your technical acumen in demolishing the proof made by the Brazilian scientists, who may not know as much as you do about lasers.

And lastly, it bears repeating that the reason I say that the earth may be magnitudes larger is because the lack of a noticeable curvature makes earth appear flat. I did not literally say this, but it was implied but I was mistaken in thinking someone like you would pick up on it. Maybe you did, but you just had to use that against me. Touché.
Can you link the experiment, I can't find anything when I searched it other than a documentary with a small experiment that made headlines and was debunked. Nothing about Brazilian scientists.

Let me be clear I have no training, but what I am good at is voraciously learning what I don't understand, friends and family come to me with their health problems because of it, one of them thinks I should have been a researcher. I don't need to be right, but what I can't stand is ignorance. If someone doesn't understand the physics of our world to explain phenomenon then learn about it! Research research research! Without the equations that have been figured out long long ago you would say the earth looks flat. But it wouldn't hold any weight in any scientific discussion because we have already figured out what the curvature is. The earth IS huge, very very huge. We are specks on the huge earth.

If you don't know physics you wouldn't know how to calculate the horizon and what things would look like based on the radius of the earth. Using the cascade mountain example from before this is what a flat plane would have looked like:
south sister flat with lines.jpg



Mt Rainier would have been towering over Olallie and would be the tallest in this photo, but it isn't Rainier and Olallie look almost the same size!!!! That is because the earth is exactly the size we have already figured out and Rainier is going over the horizon.
 

Perry Staltic

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No what is happening is the apple is less dense than the water so the apple can't hold the water down so it gets pushed upwards , but take say a rock and it will fall to the bottom of the tank because it can hold the water down. It's easy to test yourself if you record it and watch it in slow motion it's easy to see the water pushing the object upwards of course the water doesn't have a mind of its own thinking to push upwards lol well I've given you experiments how about you give me an experiment to prove its the force of gravity pulling objects down? Otherwise you saying gravity did it is just the same as a religious person saying God did it.

I guess an easier way to understand it could be with a spring let's say you have a spring and you are strong enough to hold the spring down with your finger this is the same as a rock falling to the bottom of the tank because it is dense enough to hold the water down, now if you aren't strong enough to hold the spring down then it will spring upwards and push your finger upwards this is the same as the water pushing the apple upwards because the apple isn't dense enough to hold the water down

A rock doesn't hold water down; it has no buoyancy so it sinks and displaces water upwards. Water isn't trying to rise unless it's warmer (i.e., less dense) than surrounding water, so it can't lift anything by itself.

You can't compare fluids/gases with solid objects. Individual fluid molecules move and displace under force, but molecules in solid objects don't move, so the object itself has to move..
 

Jing

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A rock doesn't hold water down; it has no buoyancy so it sinks and displaces water upwards. Water isn't trying to rise unless it's warmer (i.e., less dense) than surrounding water, so it can't lift anything by itself.

You can't compare fluids/gases with solid objects. Individual fluid molecules move and displace under force, but molecules in solid objects don't move, so the object itself has to move..
Looks like we are getting somewhere.. yes the rock displaces the water, and with an apple because its less dense than the water the water displaces the apple which makes the apple go upwards.. I'm not sure why you need to add gravity to this? Can you give an experiment which shows gravity pulls objects down?
 

Perry Staltic

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Looks like we are getting somewhere.. yes the rock displaces the water, and with an apple because its less dense than the water the water displaces the apple which makes the apple go upwards.. I'm not sure why you need to add gravity to this? Can you give an experiment which shows gravity pulls objects down?

The only way the apple can go up is if water above it is going down, which displaces and lifts the apple. There's no force above or within the the apple pulling it up.
 

Jing

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The only way the apple can go up is if water above it is going down, which displaces and lifts the apple. There's no force above or within the the apple pulling it up.
There is, when you are holding the apple at the bottom of the tank that water that the apple has displaced has to go somewhere right? So when you let go of the apple the water rushes back in place and displaces the apple..
 

Quelsatron

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No, it isn't a straw man as I refer to the attitude Staltic hold, and I use climate science as an example of how consensus can take the place of real experimental proof to establish that climate change is caused by man's activities. How could he deride and insult someone as being from the dark ages and yet be oblivious that we are far from being enlightened when chicanery is used to keep people in the dark by the the high priests of science.

And you stand with Staltic on his high fallutin attitude?

As far as lasers go, I don't know you know so much about how they bend and follow the curve of water surfaces such that over long distances they would just follow the contour of the curvature of the earth and then hit right smack an object that is at the linen of sight at the same height as the source of the laser light.

I'm not a scientist and I probably should not engage you in technical matters that I underestimated you on. But if that is your way of disproving the Brazilian scientists, then I should defer to your technical acumen in demolishing the proof made by the Brazilian scientists, who may not know as much as you do about lasers.

And lastly, it bears repeating that the reason I say that the earth may be magnitudes larger is because the lack of a noticeable curvature makes earth appear flat. I did not literally say this, but it was implied but I was mistaken in thinking someone like you would pick up on it. Maybe you did, but you just had to use that against me. Touché.
1_8x5qar5YhqLh7SLMrCVcXw[1].png

Hot asphalt and cooler air causes mirages that curve the light upwards, shown here by light rays emanating from the car appearing lower, i.e they're coming in at an upwards angle into the eye of the observer, meaning they were sent downwards, curved upwards and then came in from below in an upwards angle. Conversely, if the temperature gradient is inverse, this will cause light rays to curve downwards, which naturally extends them further towards the earth. And I'm not sure how you decided that the earth was a big ice ball covered in flat earths, because i saw that image and I'm pretty sure it was a meme.
 

InChristAlone

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Jing

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Since I love photography and this is still on topic, thought I'd share these stunning photos from Mt South Sister from 10,355 ft elevation from hikers:
Photo taken with a Panasonic DMC-ZS19 4.3mm
View: https://www.flickr.com/photos/keppnw/9242058601/


View attachment 28943


That curve is looking stunning!
Let's compare it to the curvature tool Finding the curvature of the Earth
View attachment 28948
I combined the images in gimp

View attachment 28955
It's a near perfect match! Curvature tool confirmed as proof to measure horizon!

This isn't curvature it's just an illusion you know how many miles you are looking out infront off you and you expect to see perfectly? No distortions or anything because that's all this is distortion. What should be happening is a dip downwards a big dip downwards considering boats apparently go over the curve about 3 miles out. You can replicate what your seeing here on a small scale on a flat surface this doesn't prove we live on a sphere.
 

boris

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If gravity is pulling all objects to the ground then the apple shouldn't float on water but be at the bottom of the tank.
I can pull with a constant force at a string attached to a rock without moving it. There is a threshold.

No what is happening is the apple is less dense than the water so the apple can't hold the water down so it gets pushed upwards , but take say a rock and it will fall to the bottom of the tank because it can hold the water down.
I'm not sure why you need to add gravity to this?
Why would something more dense "hold" something down?

Can you give an experiment which shows gravity pulls objects down?
You just proved it with your own experiment.
 

boris

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You can prove the roundness of the earth for yourself by putting a stick in the ground in different places and comparing the shadows they cast.





"Eratosthenes had heard from travelers about a well in Syene (now Aswan, Egypt) with an interesting property: at noon on the summer solstice, which occurs about June 21 every year, the sun illuminated the entire bottom of this well, without casting any shadows, indicating that the sun was directly overhead. Eratosthenes then measured the angle of a shadow cast by a stick at noon on the summer solstice in Alexandria, and found it made an angle of about 7.2 degrees, or about 1/50 of a complete circle.

He realized that if he knew the distance from Alexandria to Syene, he could easily calculate the circumference of Earth. But in those days it was extremely difficult to determine distance with any accuracy. Some distances between cities were measured by the time it took a camel caravan to travel from one city to the other. But camels have a tendency to wander and to walk at varying speeds. So Eratosthenes hired bematists, professional surveyors trained to walk with equal length steps. They found that Syene lies about 5000 stadia from Alexandria.

Eratosthenes then used this to calculate the circumference of the Earth to be about 250,000 stadia. Modern scholars disagree about the length of the stadium used by Eratosthenes. Values between 500 and about 600 feet have been suggested, putting Eratosthenes’ calculated circumference between about 24,000 miles and about 29,000 miles. The Earth is now known to measure about 24,900 miles around the equator, slightly less around the poles."


"Shadowless in Syene​

Eratosthenes knew that no shadows on the Summer Solstice meant that Syene was on the boundary of the northern tropic zone (the Tropic of Cancer).
By measuring the length of the shadow in Alexandria at noon on the Summer Solstice when there was no shadow in Syene, he could measure the circumference of the Earth!

High Noon on the Summer Solstice
eratos_sm.gif


At Syene:The Sun is directly overhead, no shadows are cast at that moment.


At Alexandria:The Sun is 7 12/60 degrees south of overhead, casting shadows.
Since a full circle is 360 degrees, the arc from Alexandria to Syene is thus approximately 1/50th of a full circle (the sun angle above divided by 360).

Therefore, the circumference of the Earth is 50 times the distance from Alexandria to Syene.

Question 1: How far is Alexandria from Syene?5000 stadia


Question 2
: How big is 1 stadion?600 Greek Feet (length of a foot race in a Greek "stadium")
The best modern guess is that 1 stadion = 185 meters, based on the "Attic Stadion" measured from the Stadium at Athens.[4.2]

Putting Eratosthenes result into modern units, his estimate of the circumference of the Earth is as follows:

Circumference = 50 x 5000 stadia = 250,000 stadia
250,000 stadia x 185 meters/stadion = 46,250 kilometers

The modern measurement is 40,070 kilometers.

Eratosthenes' estimate is only about 15% too large!"
 
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Jing

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I can pull with a constant force at a string attached to a rock without moving it. There is a threshold.
Because you are a human with a mind who can decide how much force too use. If an apple is just resting on water and gravity pulls everything down then you would constantly see the apple trying to be pulled underneath the water.

Why would something more dense "hold" something down?
The more dense object displaces the less dense medium.

You just proved it with your own experiment.
No I didn't I showed that if you change the medium an object will rise or fall nothing to do with gravity.
 

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