Gravitas

Gravity keeps your feet on the ground, as well as just about everything else. I'll not bore you with the Principia or go into the story of Isaac Newton and the apple as I'm sure you have heard it a hundred times or more, but a quick look on Wikipedia will tell you plenty if you have somehow got this far without hearing of the man or his work, however, the (very) basic points of gravity are as follows.

1. Every particle will pull on every other in all directions
2. The more partials in one place (the denser) the stronger the pull
3. Gravity will pull towards the centre of mass
4. The pull gets weaker with distance

Or as Newton put it

"Every point mass attracts every single point mass by a force pointing along the line intersecting both points. The force is directly proportional to the product of the two masses and inversely proportional to the square of the distance between the point masses."

Flat earth believers know that gravity can't work on a flat disk-like world. Nothing would work as we experience it in the real world, as already mentioned gravity pulls towards the centre of mass, on a flat pizza like world that would be located just below the North Pole. Standing at the North Pole would be fine and probably feel quite normal but if you were to walk south it would gradually get more and more difficult as if walking up a hill that gets steeper as you go. When you finally reach the South Pol... The rim you will feel like your climbing an almost sheer cliff, the exact inclination felt will depend on the thickness of the disc, but it would be more than noticeable. But this is Not how things appear in the real world, you can walk in any direction and down is always... well... straight down excluding any real incline due to an actual hill or mountain.

So how do flat Earthers explain the difference between real-world observations and the expected results of gravity? Simple gravity does not exist or it's just an alternative name given to an already existing force that happens to hold us down. There are many competing ideas as to how everything is held down and as with most other flat-earth "theories", no one hypothesis seems able to agree on a single answer. I'll cover a couple of them now

 

Accelerating Upwards

This one is as simple as it sounds. The world is a flat disc and it's continuously accelerating in an upward direction at 9.8 meters per second every second (9.8m/s^2). In a very basic way, this means if I was to jump into the air I would be accelerating myself ahead of the ground only for it to catch up with me as I land again. This means the flat earth is moving faster and faster every second of every day, surely this would cause problems? The simple answer is Yes, in one day we would accelerate by 1,894,059 mph (3,048,192 Km/h) and in one week 13,258,413 mph (21,337,344 Km/h). How fast would we be going after one year? Well, it would be a little faster than the speed of light which is just over 670 million mph.

 

Buoyancy

This one is quite straightforward too but also has some odd problems related to it. Heavy things sink and light things float, if you drop a brick in a bucket of water it will sink but wood will float because it's less dense than the water. The same applies to things in air, if it's denser than air it will fall and hit the ground... and that's it.. dance/heavy things fall less dance/light things float. Now that is all true I'll grant you that any physicist or secondary school student for that matter will tell you it's gravity that's doing the pulling and displacing the less dense liquids and gases. A helium balloon will float up because the air pressure underneath is pushing up with more force then the air pressure above and gravity combined are pulling it down, this imbalance in force will cause the balloon to rise. But according to flat-earth believers, that's wrong! Air pressure is what pushes everything down, gravity as we understand it is not required. All the air above our heads is pushing us down to the ground and we call that "gravity", simple right? Yes.. but this is where the problems start. If we go back to our bucket of water with the brick in it and placed it in a vacuum chamber what would stop the water or the brick from floating up out of the bucket? If I went into a pressure chamber shouldn't I feel heavier or at the top of a mountain where the air is thin would I feel lighter? What if I dropped a hammer in a vacuum would it simply float next to my hand without the air to push it down? not sure? I invite you to watch this experiment or buy/build a vacuum chamber and test it yourself. lastly, on this point, I’d like to look at a mercury barometer (left), the mercury in the tube is pushed up into the tube and let fall as the surrounding air pressure changes. If the only force acting on the mercury is air pressure what's pulling the mercury out of the tube and creating the vacuum at the top? Air pressure can only push it cannot pull, the vacuum appears as the tube is lifted into the vertical position so something must be pulling the mercury down and acting against the outside air pressure.

Neither of those examples fully explain what happens in the real world, the same goes for any other explanation other than gravity as understood in modern science. Two body's of mass will pull towards each other even in a vacuum or through any barrier. The force of gravity can be measured and by using the correct apparatus all other forces that could act upon the equipment can be excluded. The Cavendish experiment was the first to measure the gravity between two objects. The experiment used two large lead balls hung from the ceiling and two small lead balls balanced on the ends of a bar, the bar its self hung on a wire. The small lead balls would be pulled towards the large lead balls twisting the wire, this twist was measured and told Cavendish the force acting between the two masses. This experiment is still performed today in labs all around the world, I vaguely remember our physics teacher doing this at school but at the time I found it very boring as it's very, very slow and requires no safety equipment. you can find plenty online about it and anyone with the space and time can perform it, although accurately measuring the results requires high precision and a lot of prep work to exclude any interference. I hope to be doing this sometime in the near future (providing I can sort out a space to do it) and I will walk through my set up and finding hear.

The only conclusion I can come to at the moment is that gravity as Isaac Newton understood it must be real, a force is clearly present and yet nothing else I have seen explains all its property's. There are serval experiments that test it and help to define its laws, if gravity did not exist the experiments they would not work or would produce differing results.