PeterDonis's latest activity

I don't agree with you calling the definition ##a(t_0) = 1## "normalized", which is what you're doing here. It's a convenient...

I think my objection to the utility of simultaneity is its use at large scales, rather than small. Tangents and normals are local...

But the scale factor does not have to be normalized to the proper distance; that's the point. It doesn't matter how the scale factor is...

Even if I accept this, the variable here is not the scale factor but the ratio of scale factors, and it only has a "maximum value" of...

You've been using ##t_0## all through this thread up until post #31, when you used ##t_{rec}##, and that was in response to @Ibix using...

So now you're changing the definition of what variable you're using? Or did you really mean ##t_{rec}## before when you wrote ##t_0##?

Yes, but we still expect our physical models to cover other times besides those when we are alive. And that includes times to our future...

If this were true, no ##t## other than ##t_0## would have any meaning and this whole discussion would be pointless. I think you have...

This is only true if ##t \le t_0##. What if you're trying to compute something for a time ##t## that's later than now (##t_0##)?

What is "equal" about two results that differ numerically by a factor ##\left( 1100 + 1 \right)##?

So by "normalized" you mean "less than or equal to 1"? Where are you getting that definition from? I still don't see how this is...

No, it doesn't. Spacetime is a 4-dimensional manifold, so it takes 4 coordinates to define a frame. This is not a coordinate, it's a...

What you mean is that freely falling objects at rest in a rotating frame do not stay at rest. But that's a much more restricted thing...

It isn't. There are absolutes ("invariants" is a better term) associated with rotation, but "rotary motion" itself, at least not with...

@Physicist248 since you have opened a new thread on linear vs. rotary motion, further discussion of that point should be done there...