Lately, I’ve been posting in flat earth social media, mostly asking why ships appear to sink behind the horizon when they sail away. Why? Because of XKCD number 386.
One thing I’ve noticed is the flat‑earther’s need to deny gravity. I’m not sure why because gravity is one of the easiest things to demonstrate. You drop something, it falls towards the ground instead of hanging in mid-air. That’s it.
Flat earthers seem to tie themselves in knots trying to replace gravity. They’ll invoke buoyancy without realising that it depends on gravity to work. They’ll invoke electrostatic forces which doesn’t depend on gravity but breaks down when you ask where the like-charges-repel effect has gone.
One even told me that Beyoncé was responsible for objects staying on the earth, but I’m quite sure that was an autocorrect error.
All I Want for Christmas is Glue
So, as a friendly glober with a GCSE in high school physics, I thought I’d help. Let’s see if we can integrate some form of gravity into a flat earth.
Introducing Flat‑Earth Gravity™.
Put away your books on Newtonian motion or relativistic physics. This isn’t that.
This is the force that pulls objects towards the ground. Exactly what you see when you pick up a ball and drop it. This force behaves exactly as required for a flat earth to function and not at all like any force known to Glober physics.
What direction? It pulls towards the ground. Perpendicular to the surface of the flat Earth at a constant 9.8 m/s² everywhere. The same acceleration you can measure for yourself with tennis balls and a stopwatch.
Drop a ball in London: down. Drop a ball in Brazil: also down. Drop a ball on the ice wall at the edge of the earth: Get down tonight!
These “down” directions are parallel, because this force is uniform across the entire disc of the earth. All perpendicular to the flat earth surface. This conveniently avoids the need for the Earth to be infinitely large, which is what Glober physics would require.
And crucially, Flat‑Earth Gravity™ does not pull toward the centre of mass. This force is always downwards, never sideways. This is why the flat earth doesn’t collapse into a sphere and why walking outwards towards the edge isn’t like climbing a hill. That’s what you’d get with Glober Gravity, so don’t get them mixed up.
There you go. Gravity fixed. Now flat earthers can stop arguing about density and start arguing about why their new custom‑built force doesn’t also pull the Sun and Moon into the ground. Maybe that’s because of Beyoncé. Or buoyancy.
And to those who point out that “All I Want for Christmas” is Maria Carey. Shuddup.
Credits
📸 “Daventry Ducks” by me.
Thanks to “Ozteric Oz” for the inspiration.