system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If two identical balls are connected to the same very long rope, and one of the balls are floating in space and the other one is hanging above earth's surface. What would happen?

So my 7-year old asked me this and as much as I would love to be able to give him a proper answer, I couldn't.

Does ball A (in space) float away, taking ball B (above earth's surface) with it? Will the balls stay somewhat fixed or will ball B force ball A down?
gpt
All of these outcomes are possible, depending on the exact location and speed of the balls. It is possible to set up the balls above the equator in such a way that they’ll just stay there - the lower ball hovering near the ground and the upper ball circling in orbit around Earth. You can then go up and down the rope to get into orbit and back at a fraction of the cost compared to rockets. This is the basis behind the concept of “Space elevator”. You can look it up and tell your seven-year old they’ve come up with a great idea independently. Technically the only setback is that we don’t yet have material strong enough for the rope, but we are kinda close to it, so it’s not unrealistic to hope that we will have it eventually.

Edit: somewhat expanded.