Good! I agree. Relativity does not agree however. It insists that not only is time (and width and height (i.e. space) a real thing but that it can be manipulated by gravity and one's velocity.
I never claimed that time was not a
real thing, I stated that I don't think of it as a
physical object. Time is certainly a
real property, inasmuch as length/width/height are real properties. There is no aspect of relativity which demands that time is a physical object in and of it self -- certainly no more so than any other equations which include time as a variable. Relativity simply assumes that time is a quantifiable measure.
It's also incorrect to claim that relativity assumes that
space is a real thing. Common usage of the term spacetime is not actually referring to physical objects
space and
time (although some pop-sci literature may make this mistake). Einstein did away with the notion that there is a physical object known as space (i.e. the aether). Spacetime is more accurately a Lorentzian manifold, a mathematical representation of a vector field. For convenience it is often shorthanded that "x travels through spacetime". This is a reference to the
field spacetime, not a physical object known as spacetime.
Johnny said:
As you note, it's just a clock that both observers can see and which is not affected by either observer's local gravitational conditions (in Bob's example). The error is introduced when you assume that the "giant wall clock" is actually measuring a set time for either observer. It's not. It's not measuring time for either observer because it's not subject to the same local conditions as either observer, and therefore it is not a valid clock for either of the observers.
Clete said:
I bet both observers would argue with you when they wanted their morning papers to arrive somewhat closer to sunrise rather than sunset.
Assuming a third party paperboy exists outside the extreme relativistic effects described in this hyperbole (perhaps he lives very far away from this mountain), the morning paper would arrive at sunrise for both observers. Though the observer at the top would correctly note that it's only been a few hours since the last paper arrived.
Clete said:
Any clock that gives you a reference by which you can describe duration and/or sequence is a valid clock
According to relativity its only a valid clock for observers under the same conditions as the clock.
Clete said:
and any clock that is more consistent across multiple frames of reference is, by definition, a more reliable clock.
The trouble here is that any clock outside the inertial frames of either observer is actually
less consistent. For the observer at the top of the mountain, the sun is rising and setting at a very fast pace; whereas for the observer at the bottom of the mountain its rising and setting at its normal pace. In other words, the two observers do not agree on the interval in which the sun rises and sets (hence the interval is relative). And since the clock does not describe an invariant interval for both observers, it is not a "more valid clock". It's actually
less valid because the interval it describes will be debated between the two observers. Once again, relativity posits the only valid clock is the clock in the same inertial frame as the observer.
You are using Bob's hyperbole as a foundation for your argument, and then asking us to make some consideration regarding clocks and time, etc. And when doing so, you ask us to consider "
if relativity were true,
then..." You then point out some observations which show that relativity could not be true. The problem is that you are not painting an accurate picture of what relativity actually implies -- such as when you say "any clock is valid" or when you insist that clocks under a relativistic scenario would remain "in sync with each other."
If you are trying to argue against relativity by assuming a relativistic scenario and then pointing out apparent incongruities, then you need to at least assume a proper relativistic scenario. You are not doing so, and therefore the conclusions that you've reached are as invalid as the assumptions you made. That's why I've spent a significant portion of my discussion with you saying "that's not what relativity assumes."
Clete said:
If it were time itself then the Sun would be down for one and high in the sky for the other because the position of one observer on a mountain top has no effect whatsoever on how long it take for the Earth to spin on its axis.
Johnny said:
Why would it remain in synchrony with the sun? That would not be relative time, that would be absolute time.
Clete said:
Because the Earth spins on its axis once every 24 hours.
No. The Earth spins on its axis once every 24 hours in our "every day" inertial frame. For someone in a highly relativistic frame, the Earth's rotation is not 24 hours. Again, we're supposed to be assuming a relativistic scenario here. You prefaced your initial statement with, "
If it were time itself" -- in other words,
if it were as relativity implies. You started your argument by asking us to take on a relativistic picture, and then you proceed to defend your argument with assumptions that are not relativistic assumptions. That's why my initial response pointed out that you've switched mid-argument from a relativistic picture to a non-relativistic picture. In relativity, the interval of an event varies based on your velocity and the gravitational field.
Clete said:
If a person's hours are slowed down that shouldn't have any effect on how many times the Earth spins on its axis in 24 of them.
Sure it does. The earth's rotation can be measured in meters per second. If you're measuring seconds differently than someone else, then you will argue that the Earth is rotating at a different speed. That doesn't mean the Earth has actually changed its rotational speed -- it means that you're measuring the interval of one second differently than someone else is. Remember earlier when we agreed that time is not a physical object, but rather a measured property? This is where it comes into play -- we measure time differently.
Clete said:
This ignores the fact that you have a second observer who agrees entirely with the first observers observations of the Sun and it once again confuses a discussion about clocks with a discussion about time itself. I do not deny that people's
Since this paragraph got cut off I'll leave it be.
Clete said:
So you agree then that to say time is relative is semantics and that what you are really saying is that the reading on clocks is relative.
I can't agree with that semantic variation because the effect relativity implies is not just
the reading on a clock, but rather it's all events which occur in intervals that are subject to the same conditions as the clock -- be it heart beats, brainwaves, water boiling, or tying my shoes. In other words, the effect is not a property of the physical structure of the clock in any way, it's a property of the way light and matter interact at the sub-atomic scale.
Clete said:
It isn't that I'm uninterested its that its so hard to keep people on the topic.
Fair enough.