Recent content by John_Dee

Physics grad school drop out who now stalks physics discussion boards while working his electrical engineering job.

I am just a few credits shy of a physics masters degree. Perhaps one day I'll finish it.

Thanks... this is going to keep me busy for a while!

Taking the idea of a rotating (non empty) universe further, I find it interesting that the galaxies would experience centrifugal force and tend to fly outward from the axis of rotation, while the non-rotating ship in the center would experience nothing. But like you said, since it's untestable...

Perhaps not... but if you want to know my motivation for taking you all on this ride, it's because I got to reading about Mach's Principle, and the origin of inertia. Basically, the idea I got stuck in my head is this: "What is the origin of inertia? If the rest of the universe determines the...

Ok, what I'm getting from the responses seems to be that the answer to my thought experiment is YES, a rotating ship would experience centripetal force, even in an "empty" universe with no visible reference points. This makes me also think that if you rotated the entire universe around a...

Ok, so if there is no measurable centripetal acceleration, then the object cannot be said to be "rotating". But in order for each particle to experience centripetal acceleration away from it's natural "straight line" path, mustn't it necessarily have linear velocity? And that linear velocity...

Thanks, that sounds like it's probably right... but how exactly would one make such a reference-less measurement? Let's assume it's spinning at a fixed velocity. (no acceleration) If you're inside the ship rotating with it, then relative to you, it's stationary. I'm having a hard time...

Ok, so we know that if one were inside a donut-shaped spaceship that is rotating around it's axis, that the passengers will experience centripetal force. It seems obvious to say that the ship is rotating relative to the nearby stars and planets. So far, so good. But... what if we removed all...