Recent content by Happy Recluse

Thank you. With your analogy, we know that both judgments can be true: the suspect has a face and a back to his head. But suppose Smith says, "The face has a mole between his eyes," and Jones says, "The [same] face has no moles on it." Here, both cannot be true. (There might be confusion...

I appreciate your indulgence, but I am not asking about equality. I am asking about the truth, or possible truth, of competing observations. It is true that Smith claims the pattern of the bouncing ball is straight. It is true that Jones claims the pattern of the bouncing ball is not...

Is the following true: ##\frac{dx'}{dt'}=\frac{dy'}{dt'}=0## is not ##\frac{dx}{dt}=\frac{dy}{dt}=0##?

The inconsistency lies between the two reports, i.e., the ball does not move straight up-and-down and not straight up-and-down (p and not-p). One of these two reports is true and the other is false. The inconsistency occurs even if no one knows which of the two is true.

Okay, so how does the stress energy of an object cause the curvature of space-time?

Nugatory says, that “The trace of the tensor is a powerful mathematical tool indeed, but I'm not sure why it has anything to do with the curvature of space-time.” Since your understanding of physics includes explanations beyond mathematical models, we can return to the original question: What...

Fascinating. Is there any mathematical objection to action-at-a-distance?

Right. My conditional contains the premise: "there is no gravitational force." So we agree there is no gravitational force, but that doesn't explain the cause of the curvature. In the olden days we said that large objects exerted more force over smaller objects because the increased mass...

If your conclusion is that both reports are true, then the reports are inconsistent. One or both are false. Are there branches of physics that explain illusions? Perhaps such a branch can explain that the stationary observer reports an illusion of the ball moving in a W pattern, while...

If that role is not gravitational force, then what is it?

I have a similar question. If gravity were a field generated by the mass of an object, we see why objects are drawn to a large object, i.e., why the moon is drawn to Earth. But if gravity is curved space, then why assume that space is curved to draw smaller objects toward larger objects? We...

It seems that this premise gets translated into "if two observers report different things, both of the reports are true." For example, the observer bouncing a ball on a moving railroad car reports the ball moving straight up-and-down, while the stationary observer watching the ball reports it...

I think my question is simpler than what I set out before. Let me see if I can clarify what I want to know. If I am pursuing a beam of light, I will measure it moving away from me at 300,000km/s. If I accelerate, the beam will still move away from me at 300,000km/s. I assume that if I slow...

The speed of light in a vacuum is constant because it participates in no inertial reference frame. If I am moving at 300m per second and shoot a beam of light ahead of me that beam travels at 300,000m per second irrespective of my speed or my motion. If I increase my speed, time slows down...

The starting point for special relativity is the thought experiment. These experiments generally describe two different observations of a single event, and the experiments assume that both observations are true. To be clear: the assumption is that both of the different observations of one...