Gravity Works Like This

[OnlyMe]

What's your game, mate? You're taking your 'sitting on the fence' angle to (painful?) absurd wishy-washy lengths.

Have you been watching/reading all these discussions properly?....

GR effects on clocks is PROVEN empirically EXACTLY as predicted by Einstein.

They can BE consulted DIRECTLY via the clock counter cumulative counts and COMPARED....LOCALLY and EMPIRICALLY for REAL not 'abstract'.

And Einstein already said in his GR 'rider' to the 2nd Postulate that the validity of the SR-only 'constancy of speed of light' view is NOT VALID in GR contexts.

Everything that Farsight and I have pointed out is empirically supported, as compared to the purely SR and 'abstract/remote co-ordinate overlays that are MADE MOOT by the LOCAL GR REALITY EFFECTS as Einstein predicted and are observed DIRECTLY in clocks in GR contexts.

So what are you complaining about? There IS the LOCALLY REAL as predicted EFFECTS to consult directly and cofirm GR Relativity as Einstein predicted. What MORE do you ant than that, OnlyMe?

You don't often see the word "exactly" used by.., well.., I don't remember ever seeing that word used by a respected theorist.

It is not the local experience and experimental data that is at issue, it is the run away conclusions that follow...

 

[Undefined]

You don't often see the word "exactly" used by.., well.., I don't remember ever seeing that word used by a respected theorist.

It is not the local experience and experimental data that is at issue, it is the run away conclusions that follow...

Who's talking THEORY, I just pointed out the EMPIRICALLY CONFIRMED LOCAL GR EFFECTS REALITY which was predicted by the theory. At that stage it is the REALITY that should TAKE OVER from the theory and move forward to better reality ToE complete and consistent in the WHOLE reality. Just as once you have learned the ABCs you then move on to actually composing comprehensible words. Yes?

 

[OnlyMe]

Who's talking THEORY, I just pointed out the EMPIRICALLY CONFIRMED LOCAL GR EFFECTS REALITY which was predicted by the theory. At that stage it is the REALITY that should TAKE OVER from the theory and move forward to better reality ToE complete and consistent in the WHOLE reality. Just as once you have learned the ABCs you then move on to actually composing comprehensible words. Yes?

Your post quoted above contains no useful information.

 

[Undefined]

Your post quoted above contains no useful information.

Yu don't know the difference between theory and empirically evident local reality? That explains a lot as to what reasonable people are up against. Some priests are just like that, they still prefer fantasy to empirical reality under their nose. Good luck with that, OnlyMe.

 

[Farsight]

Can you explain your reasoning as to why that is a great question?

To be clear, I’ll define space as separation between two or more points, and motion as a change of position in space.

Meaning if something like you hand changes from one point to another point that is not as the same location (it is separated by space), that “waggling of hands” demonstrates motion. You may have just wanted to see Farsight’s answer and if that is the case ignore this paragraph. I would still like to understand why you think it was a great question?

He just isn't sincere, Maxila. You can see motion, you can't see time, so it doesn't make much sense to claim that you need time to have motion. And when you look inside a clock and see things moving instead of time flowing, you hopefully appreciate that actually, you need motion to have time.

 

[Farsight]

Undefined, whether you believe that the speed of light is variable or not, $$c$$ is a constant, used in everything from SR and GR to quantum mechanics and cosmology. Maybe you should introduce a new term $$c_{varriable}$$

It's called the coordinate speed of light. Look it up.

 

[Grumpy]

Farsight

It's called the coordinate speed of light. Look it up.

You should look it up. Coordinate speed is not the same thing as the speed of light through spacetime c .

Coordinate speed is the distance between two points divided by the time it takes to transit between those points. It is a DERIVED value and varies in accelerated frames.

The speed of light is the actual speed at which all radiation always travels in empty spacetime. c It does not vary or change, ever.

Such a simple mistake in your understanding upon which you base the garbage that you have been posting.

The quote-mining is just dishonesty, a character flaw. Remember, character is something you should have, not something you should be.

Grumpy

 

[Grumpy]

RC and Farsight

There is no difference between invariant lightspeed and constant lightspeed. Light is invariant and constant and it's actual speed through spacetime c never changes(that's what constant and invariant means).

The coordinate speed of light varies as the curvature of spacetime increases. The coordinate speed is a DERIVED value, not the reality. As light always follows the zero energy geodesic, the more spacetime is bent the longer it takes to travel that increased distance, the slower the coordinate speed is, but the photons all continue to travel exactly the same speed through that increased distance. Your total inability to understand the difference between coordinate speed and c is the cause of your getting everything about Relativity wrong.

Grumpy

 

[Farsight]

As you all know I never put somebody on ignore for ever. After a week or so I'll have a look at what some guy is saying and maybe take him off ignore.

...it's actual speed through spacetime...

Spacetime is a mathematical model that combines space and time. It's sometimes described in terms of a "block universe", where we drop one of the spatial dimensions and depict the time dimension vertically. Then we draw worldlines in it. However because it has that vertical time dimension, there's no motion through it or in it. It's static. Light moves through space, but it doesn't move through spacetime. So that's a fail for Grumpy. Hence:

This message is hidden because Grumpy is on your ignore list.

 

[PhysBang]

Spacetime is a mathematical model that combines space and time. It's sometimes described in terms of a "block universe",

Sometimes, by idiots who do not follow the literature and thus do not understand the difference.

where we drop one of the spatial dimensions and depict the time dimension vertically.

Sometimes, by idiots that have never worked through a physics problem.

Then we draw worldlines in it.

Worldlines are merely the description of a certain path. We could merely call them paths.

However because it has that vertical time dimension,

Time could be horizontal. Or not drawn on a graph at all.

there's no motion through it or in it. It's static.

This really is idiocy, since in order to describe something in physics, you need to have a time coordinate. No time coordinate, no physics. No space coordinate, no physics. Time and space coordinates? Spacetime.

 

[PhysBang]

GR effects on clocks is PROVEN empirically EXACTLY as predicted by Einstein.

They can BE consulted DIRECTLY via the clock counter cumulative counts and COMPARED....LOCALLY and EMPIRICALLY for REAL not 'abstract'.

One cannot directly prove a theoretical science like GR.

 

[Grumpy]

Farsight

As you all know I never put somebody on ignore for ever. After a week or so I'll have a look at what some guy is saying and maybe take him off ignore.

In other words you run and hide from someone who calls BS on your posts and peek out after a while to see if they have gone away. Got it.

Fact: Lightspeed is constant and invariant in all frames.

Fact: time and space are one thing, spacetime.

Fact: the coordinate speed of light is not it's speed through spacetime, which is constant and invariant in and between all frames. It is a DERIVED, ABSTRACT FICTION.

Grumpy

 

[PhysBang]

He just isn't sincere, Maxila. You can see motion, you can't see time, so it doesn't make much sense to claim that you need time to have motion. And when you look inside a clock and see things moving instead of time flowing, you hopefully appreciate that actually, you need motion to have time.

How do you see motion? Can you describe what it is that you see when you see motion?

 

[PhysBang]

In other words you run and hide from someone who calls BS on your posts and peek out after a while to see if they have gone away. Got it.

It's like Farsight approaches citation: pay attention to one sentence that supports his claim and ignore the rest.

 

[Maxila]

It is great because of something that you (somewhat) left out of your definition of motion: time. You implicitly referenced the change in position from one time to another in your definition.

Farsight believes that there is no time, only motion. Yet he has not shown us how we can "see" motion without time.

I didn't leave out time, empirically time is coincident with motion using either term means the same thing. Again empirically for any observation or experiment you can devise a change in time is a change in position (motion), for those observations we see only energy and space (separation), time or motion is not an observable entity but rather the description or explanation of the energy changing position relative to a distance (separation). That is analogous to saying for mass we see only a quantity of energy and we describe the quantity we see as mass, in other words, mass is not the entity energy is and mass describes a characteristic of energy (its quantity), just as time describes a characteristic of energy (its change of position relative to separation). The only difference is time and motion describe the same thing, empirically it is an axiom that they are one inseparable dynamic.

 

[Aqueous Id]

I didn't leave out time, empirically time is coincident with motion

Time happens at the same time as motion? :bugeye:

using either term means the same thing.

Except when it doesn't. The charge on one plate with respect to another is proportional to e[sup]at[/sup] which breaks that logic.

Again empirically for any observation or experiment you can devise a change in time is a change in position (motion), for those observations we see only energy and space (separation), time or motion is not an observable entity but rather the description or explanation of the energy changing position relative to a distance (separation).

Yeah except time really doesn't need to be redefined.

That is analogous to saying for mass we see only a quantity of energy

Except when we don't which is why we call it mass rather than energy.

and we describe the quantity we see as mass,

Unless we see it moving and then we call it a mass with kinetic energy.

in other words, mass is not the entity energy is and mass describes a characteristic of energy (its quantity),

Uh, no, the energy of an electric field needs no mass to redefine it.

just as time describes a characteristic of energy (its change of position relative to separation).

Except when it doesn't.

The only difference is time and motion describe the same thing, empirically it is an axiom that they are one inseparable dynamic.

No actually the only difference is that this isn't right at all.

 

[PhysBang]

I didn't leave out time, empirically time is coincident with motion using either term means the same thing.

This can't be the case, since we can speak of some objects moving and others not moving.

 

[Grumpy]

Maxila

Movement-change in spacial coordinates over time. Requires 4D spacetime to describe.

Velocity-rate of change of position over a set time. Requires 4D spacetime to describe

Position of an event-coordinate values in spacial dimensions at a stated time. Requires 4D spacetime to describe

Spacetime is both a way of thinking and an accurate description of reality. Reality acts as though spacetime is a real thing, to an excruciating level of accuracy. The spacetime model was adapted because that is how reality is seen to behave. Maybe not the last word, but the latest and most accurate word we have for the last 100 years or so. Any alternative will have to do better than that, I just don't see that happening yet, not even close.

Grumpy

 

[Maxila]

This can't be the case, since we can speak of some objects moving and others not moving.

When you speak of an object not moving for a duration, how has the observer experienced or referenced that duration without any motion (macro, molecular, atomic)? The common mistake is to forget the experience of time or the reference to a change of time (like a clock) requires motion.

Empirically change requires motion, hence a change in time requires motion. It is common and intuitive to think of time as changing, being separate and void of motion but nothing can be observed to change physically without a change in position (motion/time are the same). That is why time is said to have come into existence at the big bang, in a singularity there is no space (separation) in which to calculate a change in position (motion), therefore no way to calculate time which is the same and coincident. Time can only be observed empirically when there is some increment of space to account for a change in position.

When you get your head around that, the coupling of space and time is as obvious as any axiom can be, space (separation) requires the ability to change position to have any meaning, and the ability to change position requires space.

 

[phyti]

#446 grumpy
But every effect that Relativity tells us to expect are real effects, not perceptions.

Perceptions are real, since they are mental images formed from sensory input (light) from the universe. As the anaut example demonstrates, all perception does not correspond to actual physical phenomena outside the mind. The 'motion picture' is an excellent example where the mind 'sees' motion where there is none. The person hallucinating has images which are real to him, but no one else sees them.

#447 grumpy
Q: Exactly why is the speed of light a constant in all reference frames?

A: Because it simply is.

The invariance of the speed of light in all uniformly moving reference frames is a postulate of special relativity, it does not derive from special relativity, which only then states how observers will experience/measure space and time given the invariance of the speed of light.

Q:What does the word 'spacetime' mean?


A: It means that in our universe, 3-dimensional space and time form a single indivisible new physical object which has 4 dimensions. All physical laws and phenomena seem to require thinking about space and time as this blended object. That's what Einstein's relativity theories were all about.

The propagation speed of light c, is constant. Why the measured speed is c can be derived from the theory.

Minkowski revised Einstein's SR into a mathematical 4D theory. People such as Briane Green present it metaphorically as moving in time.