Over the years, I’ve come to realize that I really like the Earth, so I want to put a ring on it. Foregoing a high tech solution involving space elevators, I wish to do this with stone age technology because my love, like my diet, is paleo.
So what I propose is a line of Stonehenge sized blocks elevated 10 feet off the ground and shaped exactly so that when they circle the earth, they lock into each other like a stone arch. Theoretically, the forces of gravity and compression along with the stones’ mass should counter-intuitively work together to keep this structure floating above the surface of the earth without any vertical support, right? What kind of pressure would be exerted on each block? Enough to make them hot? Is stone an adequate material?
For the sake of this thought experiment, let’s assume the ring has a clear path and people are not idiots or assholes so we can have nice things. Now, everybody gets on a stepstool, reaches up and gives this ring a nice little push, getting it spinning. So now we have a near frictionless conveyor belt, flywheel, prayer wheel, or what have you. Is this thing scientifically sound? Can I pursue this super-low orbital God-taunting juggernaut of hubris as a thesis project for my Ph. D. in supervillainy? Because while Mr. Supervillain is cool, Dr. Supervillain would really make my mom happy.
Short answer: The slightest perturbation will lead to one side of the ring getting slightly closer to the earth than the other side. Gravity is stronger when things are closer. The ring will drift inwards and touch the earth, and the whole thing will collapse.
Suppose it’s built on the equator with one point already touching, or at least solidly anchored, to the ground and the rest of it above the ground and unsupported. I’m pretty sure that it would still fail somehow, but how?
It wouldn’t be stable. However, if you also put in the vertical standing stones as supports it would work I think…though, of course, you’d need to level continents and fill in seas to do it. Still, if you were god king and all of humanity was at your Beck’s and Colner, I think you could make it work. Then it would sort of orbit the earth at the requisite height…at least until there was an earth quake or something along those lines to knock out the supports.
If you’re allowed to support it with vertical stones, then we’ve already done a lot of this with things like phone and power lines.
But without vertical support, you’d never make it work in real life. The Earth itself would screw you up because it isn’t uniformly dense, so some areas have slightly more gravity than others. You would need a perfectly smooth, perfectly uniform, perfectly shaped Earth. And even then, the first gust of wind would still knock it out of balance. Here’s a scenario where the wind from a butterfly’s wings probably would be enough to matter.
Another issue is that it could not be “frictionless” as described in the OP. While friction with air is pretty low, it’s not zero, and we’re dealing with a pretty large object.
We’re talking about a stone arch with a span equivalent to the circumference of the earth (plus about 31.4 feet). As the span of an arch increases, so do the forces on the components. The stone blocks would crumble.
I’d expect they would first compress until it settles down to the surface, at which point the pressure is relieved. I don’t think we know of any material that won’t compress at least that much over such a long distance.
Suppose it’s some kind of carbon nanotube super material, pre-compressed if necessary, and we anchor it deep in bedrock at one point so it can’t shift.
Would we be allowed to tie drones to the structure? If we had one every ten feet say, then we could use them to stabilize the position and help relieve a bit of the compression forces.
The Roman arch and Gothic arch were limited by the physical properties of stone and that has not changed much after their invention. Practical single-span stone archs will need to be shorter than about 30 Meters reducing your ring to something that would appear to be more of a wall.
