Comment by marcus_holmes
4 days ago
I am standing on the ground. I feel 1G acceleration. My speed is not changing. How much am I accelerating?
4 days ago
I am standing on the ground. I feel 1G acceleration. My speed is not changing. How much am I accelerating?
You say later that you think gravity and acceleration look the same but cannot be the same , which is funny since that’s exactly what relativity says: if two things are indistinguishable from each other even in principle, then they must be the same. Which is what led Einstein to realize that gravity really is just a curvature in space time. Hard to wrap your head around that! But if you study relativity, you eventually understand what being relative actually means.
Your speed relative to what? There is no absolute speed. Relative to an inertial rest frame, you're accelerating upwards at 1G, which is what you are feeling and what an accelerometer is measuring. Of course, relative to the non-inertial reference frame of the ground, your speed doesn't change.
You need to take into account your entire 4-vector for speed. You don't just have a speed in the 3 spatial coordinates, you're also moving thorough the "time" coordinate, and that is happening at a slower pace near a large mass like the Earth than it would of you were far away from here.
You are more quickly being carried by the ground further from where you would otherwise be. Hope that clears it up.
Not really, no. The ground isn't moving. I'm not moving. I get that if the ground wasn't there, I would be moving, but that's not the same thing, I think?
Like I said in another response, I have always been told that acceleration is change in velocity over time. If my velocity is not changing, I don't understand how I'm accelerating?
I do understand that gravity exerts a force that is indistinguishable from acceleration, which was my original point. But that doesn't mean it is acceleration.