J.C.MacSwell

Starting off, every horizontal direction is due South. If you pick one and maintain it at 1000 km/hr you would leave the Earth at a tangent. If you followed a uniform curve to the equator at the same speed wrt a non rotating Earth frame, shortest path just above the surface, you would not be maintaining due South wrt the rotating Earth frame we generally consider, but would experience an ever increasing "apparent" vector in the Westward direction. This combined with the 1000km/hr Southern vector would put your speed well above 1000 km/hr. This would be "communicated" to the plane by the Earth's atmosphere, and require an exceptional amount of extra power to maintain against the increased drag Without the atmosphere it would be different. The only power required that would be that to produce a vertical (radial) thrust to balance the weight of the aircraft against gravity as without the atmosphere it would have no drag but no lift. You can use vectors to resolve the speed wrt the ground. 1000km/hr South plus 1670 km/hr West when it reaches the equator.

If the aging and decomposing affected it's mass or length it would not be the same, but that would be for totally different reasons.

I prefer to think of it as one reality, which can be considered from any choice of frame of reference, but I think this is where this leads... You have one rest frame (setting aside the fact that you can be described as at rest in multiple non inertial frames) That is your frame That is the frame you are in It is the only frame you are in Anything moving wrt that frame is not in that frame Nothing can move in a frame Nothing happens in a frame I think this is a little unfortunate if that is the implied context of being in a frame

I don't understand this. Does a (moving) ruler not exist in frames other than it's own rest frame? It is moving wrt the other frames. I would not think of it as "not in" them. If that is in fact the definition in physics, what advantage is there to thinking of frames of reference in this manner? It implies (to me) like something is not there.

No. Free falling into the Earth.

To the ceiling of course...assuming the elevator was filled with water and a good lifejacket was being worn...

There are still tidal forces while dropping in freefall. There are gradients in the horizontal and the vertical.

You can tell if you are accelerating wrt an inertial frame. (Swansont can correct me but I think he assumed that) The moon is accelerating wrt Earth's inertial frame, or I think more exactly an inertial frame tied to the cg of the Earth and Moon. You can verify it by changes in position over time.

Yes, sure, but what has the latest research done for us lately...

You can define a local frame where this is true, but generally I would say it is not.

The non inertial frame I described should work in SR, should it not?

As an example: On a rotating reference frame, without gravitational effects, points further from the axis of rotation should observe time running faster for points closer to the axis.

I think there is an underlying assumption that, whatever the thing is being measured, it is all the same reality, equally real in it's rest frame or another. Sufficiently accurate measurement in any frame of convenience should allow you to describe it in any other assuming you are able to correlate between the two frames. The bold is of course not a very practical approach for objects at relativistic speeds. It won't get you any data collecting work at CERN, even if you show up with a nice camera.

What frame would you choose to evaluate and compare all these proper lengths of multiple objects, and predict the effects they would have on each other, if they all have different rest frames?

Without significant relativistic effects. and adequately precise measurements of them, you cannot tell.

The difference is that time itself runs more slowly in the first case. The clock is working fine and is in no need of compensation. This is accepted and in accordance with GR. The other is an instrument error, a lack of accuracy due to a mechanical effect. This clock needs adjustment.

It wasn't time accumulation. It was instrument error. Edit: OK you could debatably have a relativistic effect.

Not sure what you are asking. If you observe something at a distance you see it in the past. It may still exist.

No. What happens at a distance takes time to be observed. You don't observe what happens now in your frame, at any distance, instantaneously.

Michel can correct me if I am wrong, but he is seeing an increase in the rate of gap increase over time between two distant non gravitationally bound points that are only gap increasing due to the Hubble Expansion. Even with a constant Hubble constant, that effect is there...the increasing distance gives them an increased Hubble effect over time, not just for distance. He might (not sure he still is) be relating the gap increase to a velocity, but I don't think he believes a light year is a measurement of time.

Isn't that one of the things about the blue/red shifting of the blackbody spectrum...the peak shifts but all the points still look right?

I don't think you can say A is not moving wrt B, as the "wrt" is defining a different reference frame, B's frame, and in B's frame that would not be true, A would be moving. So B is moving wrt A, and vice versa, A is moving wrt B.

I might be over-guesstimating the speed of adjustment but I would expect most of the rebalance to take place more radially, the vast majority of it well below the continental plates. A lot of effects going on at once, but over almost four thousand miles of depth. Similar in concept to this but globally

Tidal forces aside, as water is much more responsive, doesn't all the other matter tend do the same, find the balance with the equatorial bulge and gravity balancing the angular momentum, and generally overwhelming any shear strength the materials might have other than very close to the surface?

Sounds like a lot more efficient scheme than having a great fusion furnace 93 million miles away and relying on a very small percentage of the energy given off... Another might be having a radioactive moon glowing with the equivalent heating. Might last long enough to sustain life for a while, though I suspect not much time for higher life to evolve.