In a 3d world one can escape from the Earth's gravitational field. On the flat-world equivalent there is no escape. You can checkout but never leave. There ought to be a science fiction story based on this premise.
Things get interesting in 2d flatland.
There the field or force has to decay as 1/r because the circumference of the boundary scales as O(r). But that's the field, to get to the potential you need to integrate and then you get a function that is logarithmic with distance.
A consequence of that is the potential does not drop to zero as you go further away. Unlike what is the case for the 3d case.
If you have heard that about a random-walking bird that returns infinitely often but a random-flying bird one that doesn't, that's sorta related.
Totally unrelated, was quite thrilled to see this map of the sphere
because I had been entertaining myself by making toy globes out of paper and it seems this polyconic map was the one I had used (an interrupted version of this).
The more conventional way is to use gores using interrupted sinusoidal that look like a string of lobes connected at their common equatorial hip.
> A consequence of that is the potential does not drop to zero as you go further away. Unlike what is the case for the 3d case.
The integral of const/r^2 doesn't drop to zero as r gets larger, but approaches some constant. Unlike const/r, which is unbounded as r gets larger. So potential is bounded in R3, but not in R2.
I should have said that it rises to zero, assuming standard sign conventions.
The gravitational potential infinity of a point mass at the origin is defined to be zero.
Could you expand on why you think it approaches a constant, presumably a non-zero constant. In any case absolute values do not matter, only the potential difference matters, but am still interested in your thought.
> Could you expand on why you think it approaches a constant, presumably a non-zero constant
Because the gravitational potential between two massive objects is equal to the amount of energy it would take to separate them (from touching) out to their current distances, and equal to the amount of kinetic energy they'd have when they impacted if they started from rest and eventually came together. This is not zero for any two massive objects that are any distance apart.
If you pulled two objects further and further apart in R3, the force required at each point would drop off proportional to 1/r^2, and the total energy would be the integral of that (let's assume total mass == 1). This integral approaches a constant: for a total mass of 1 and a starting (or "touching") distance of 1 (you can't use 0 or you can't pull them apart), this integral is 1. So no matter how far apart you pull them, potential never exceeds 1. But it must be nonzero, because you could extract energy from releasing them and letting them come together.
In R2, the force required to pull them apart at each point drops off as 1/r, so the integral grows as Ln(r), and so has no upper bound.
I recognize we basically agree on all this, I'm just clarifying why I consider the limit of the potential to be nonzero as distance approaches infinity. You could extract energy from the system with a "water wheel" setup, at least at every finite distance. You could argue "but not at an infinite distance, because they'd never come together, their attraction force is 0, and where would you put the water wheel?" but that problem only comes up at infinity. We're talking about the limit as r approaches infinity, so this problem never actually comes up.
Things get interesting in 2d flatland.
There the field or force has to decay as 1/r because the circumference of the boundary scales as O(r). But that's the field, to get to the potential you need to integrate and then you get a function that is logarithmic with distance.
A consequence of that is the potential does not drop to zero as you go further away. Unlike what is the case for the 3d case.
If you have heard that about a random-walking bird that returns infinitely often but a random-flying bird one that doesn't, that's sorta related.
Totally unrelated, was quite thrilled to see this map of the sphere
https://substackcdn.com/image/fetch/$s_!8JEP!,f_auto,q_auto:...
because I had been entertaining myself by making toy globes out of paper and it seems this polyconic map was the one I had used (an interrupted version of this).
The more conventional way is to use gores using interrupted sinusoidal that look like a string of lobes connected at their common equatorial hip.
https://www.wolframcloud.com/obj/resourcesystem/published/De...
What I was working with were more like flowers, one for each hemisphere, with the pole at the center.