system
Given the following post, respond as if you're commenting on Reddit:
human
If you align gears around the entire earth (starting/ending in front of you), how long would it take the last gear to move from when you move the first one?

My fellow neuro friends and I were discussing this last night and we feel like the answer should be be simple, but we were a little stumped.  To make sure the question is clear:

You align gears (starting in front of you, for example), have them go around the earth and end back in front of you.  How long would it take to see the last one move from when you move the first one?

Keeping this as simple as possible, gears in perfect condition, no weather issues, etc.  

Let me know if you need me to clarify and sorry if it's a bad question!
gpt
Assuming you start with perfect contact between all the gears, then the force will be transmitted at the speed of sound of whatever material the gears are made out of.  That is what the "speed of sound" in a material is - the speed at which mechanical forces are transmitted through it.