- #1
PaulCam
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So I'm an Software Engineer, not a physicist, nor a mathematician. So I like to work in the qualitative, not the quantitative.
Today I hit on a problem. I've been trying to remove the concept of "down" or "inward" from my thinking of gravity and GR.
When people show the concept of space/time curvature they show the trampoline or similar curved sheet with smaller balls curving around the larger mass. But of course this still requires the concept of "down" to resolve in your head. The balls want to fall to the centre but their angular momentum around the curved surface means they follow a parabola.
So my thoughts that maybe the way space is actually curved means that there is actually no acceleration acting on the Earth orbiting the sun, it is traveling on a straight un-accelerated path, it's just that spacetime is curved by the Sun in such a way that the straight path "wraps" around in classical space to form a circle. Wall of death motorcycle rider style.
But it all fell (oops pun) apart when I considered if the Earth was to rendered void of it's angular momentum. If it isn't traveling relative to the sun at all, what would happen?
Well that damn pesky concept of "down", or even "inward" raises it's head, as of course it will "fall" towards the sun.
So, either the premise that it is purely the curvature of space causing what we perceive as gravity is understood incorrectly by me, or something is missing from my train of thought.
What causes an object to move "down" a gravity well / space curvature from rest? In effect, how is gravitational potential energy explained in GR, or rather what is it that enacts on an object a will to travel to a lower potential energy on a gravity well? It is simply that objects want to return to lower energy states?
Today I hit on a problem. I've been trying to remove the concept of "down" or "inward" from my thinking of gravity and GR.
When people show the concept of space/time curvature they show the trampoline or similar curved sheet with smaller balls curving around the larger mass. But of course this still requires the concept of "down" to resolve in your head. The balls want to fall to the centre but their angular momentum around the curved surface means they follow a parabola.
So my thoughts that maybe the way space is actually curved means that there is actually no acceleration acting on the Earth orbiting the sun, it is traveling on a straight un-accelerated path, it's just that spacetime is curved by the Sun in such a way that the straight path "wraps" around in classical space to form a circle. Wall of death motorcycle rider style.
But it all fell (oops pun) apart when I considered if the Earth was to rendered void of it's angular momentum. If it isn't traveling relative to the sun at all, what would happen?
Well that damn pesky concept of "down", or even "inward" raises it's head, as of course it will "fall" towards the sun.
So, either the premise that it is purely the curvature of space causing what we perceive as gravity is understood incorrectly by me, or something is missing from my train of thought.
What causes an object to move "down" a gravity well / space curvature from rest? In effect, how is gravitational potential energy explained in GR, or rather what is it that enacts on an object a will to travel to a lower potential energy on a gravity well? It is simply that objects want to return to lower energy states?