A Train, Three Clocks, and an Observer

Dude, we just agreed that "Distance is distance", that you can't alter an actual distance relationship by defining a different standard.

Good. Now prove you are interested. Go and look at the experiments that do what you suggest, that use light travel time to measure distance travelled.

Acknowledge that if the experimental results differ from what you think they should be, then you just might be wrong.

 

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Is it possible for the end clocks on the train to read different than each other from the mid point? Answer that directly.

 

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Right. I agree.
But what if it is impossible to verify the motion of the bus with respect to the universe? What if any test we try (without external references like the ground, or the GPS) always says that the bus is at rest?
What if relative measures of velocity are all there is?
Then we can never say that anything is at rest, right?

Well, we can't say anything is absolutely at rest.
But, we can say something is at rest relative to something else. For example, it is trivial true to say that the bus is at rest with respect to itself.

When we say "assume the bus is at rest", we don't mean "assume it is at rest with respect to the universe". We mean "use the motion of the bus as our rest reference - all velocities mentioned are with respect to the bus unless otherwise specified."

Can you agree that this is not foolish?

 

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Experiments indicates that they will always read the same for a non-accelerating train.

 

You can't alter the actual distance, but you can have a system that is inconsistent with the concept of the standards. Like for instance, A ball is on the beach. What is the velocity of the ball towards the center of the Earth? 0 m/s? So is acceleration the rate of change of velocity? At what rate is the 0 velocity changing when on the beach? Zero? So the acceleration of the ball towards the center of the Earth is zero? Hmmmmmmm.

 

No way Jose! Ever hear of redshift?

 

So you agree that distance is defined by nature?

More importantly, you could define a system that is inconsistent with nature. Such a system would be wrong. Right?

With respect to the ground, yes.

With respect to the ground, yes.
What's your point?

 

Yes way.
See if you can find experiments that use doppler to try and measure absolute velocity. Let us know what you find.

 

Distance is defined by light travel time. There is space between objects in space.

Right, and the current system is wrong. Good point.

My point is just that, that the acceleration of the ball towards the center of the Earth is 0 ft/sec^2. Agreed?

 

Because, It's true

Yes, no one has ever implied that they don't.

Of course not, because the observer wouldn't.

And every actual experiment done in the real world confirms this.

 

No, that's an arbitrary standard (albeit a very useful one).

That's more like it.

According to you.
MD, if an actual experiments show that your system is inconsistent with reality, would you consider that you might be wrong?

Relative to the ground, the acceleration of the ball towards the center of the Earth is 0 ft/sec^2.
Agreed?

 

Whoops, you forgot the last one.

Is the ball accelerating towards the center of the Earth?

 

You implying that there is a single absolute answer for this question.
I suggest that there is not. Like velocity, acceleration is relative to some reference.

The obviously implied rest reference in this case is the ground.
So, the simple answer is yes.

But, other references are possible.

 

MD, actual experiments show that your system is inconsistent with reality.
Don't you think that this indicates that you might be wrong?

 

Acceleration is simply the rate of change of velocity. If the ball has a zero velocity, and the velocity doesn't increase or decrease in a time interval, then the ball's acceleration is 0 ft/sec^2. So at the surface of the Earth, for the ball, gravity is zero, correct?

 

You can't admit the end clocks can be viewed as out of sync by the mid point observer when the train is inertial. Why can't you understand that if the train has a velocity, the end clocks will not appear to the midpoint observer as being in sync with each other?

 

No, that's stupid, and off topic.


Have you given up on arguing that you can measure absolute distance travelled using light travel times?

 

Why can't you understand that actually looking at what happens says you're wrong?

MD, do you understand that if a theory predicts some result, but experiments show a different result, then the theory must be wrong?

If actual experiments give a different result to your theory, will you realise that your theory is wrong?

 

It was an example of a misapplied notion of distance and time. The ball's velocity towards the center of the Earth while on the beach is 0 ft/sec, and the acceleration is 0 ft/sec^2, correct? How is that "stupid?"

I already explained how in the OP. I suggest you take it to heart.

 

You said that if the acceleration of something lying on the ground is zero, that means gravity is zero. That's stupid, and off topic.

Dude, you're arguing with reality. You navel-gazing OP disagrees with actual experiments.

Once more:
Are you interested in looking to see how the universe actually works?
Or are you happy with gazing into your own navel, supposing how it might work?
Would you rather believe your personal introspection about how things should happen, or actual observations about how things happen?