about Bob's article on absolute or relative time

[fool]

Yikes. Clete said "enough to cancel" which means the same as "the net gain is zero". The Wiki article and Clete said exactly the same thing.

Is ThePhy still hanging around? It's just a small mistake a man like you should be willing to own up to.

Well lets see, in my post I wrote;

Your comment about the special and general effects cancelling each other out is apparently incorrect.
From here;
http://en.wikipedia.org/wiki/Time_dilation

Unless of course you think the Navy is in on it.
Also, myself and Lighthouse were talking about distance and speed. We haven't turned the discussion to time yet so your post is irrelevent.

Notice my tone is civil, now if I miss construed wht he meant by that paragraph that he wrote then his reply he would clarify in a civil tone and the conversation would continue, instead he wrote;

You're stupid, Fool.

The whole damn discussion has been about time, and you quote of the article explicitly states what I just got through saying, you blithering idiot!

Look up the definition of the phrase "net gain", you silly moron!

Bolding by fool.
At this point I guess I really don't care what he meant as I'm done discussing it with him until he can get some anger managment classes or some medication or something. This is a discussion about physics and Clete hurling abusive language around dosen't add anything to it.

 

[Yorzhik]

Well lets see, in my post I wrote;

Notice my tone is civil, now if I miss construed wht he meant by that paragraph that he wrote then his reply he would clarify in a civil tone and the conversation would continue, instead he wrote;

Bolding by fool.
At this point I guess I really don't care what he meant as I'm done discussing it with him until he can get some anger managment classes or some medication or something. This is a discussion about physics and Clete hurling abusive language around dosen't add anything to it.

First, let me agree that Clete was quick to anger. But you are quick to avoid manning up. How was he supposed to know you wouldn't understand what he wrote? Especially since it was clear? And you still don't have to continue the conversation even if you admit that what Clete wrote and what was in the Wiki were the same.

 

[fool]

First, let me agree that Clete was quick to anger. But you are quick to avoid manning up. How was he supposed to know you wouldn't understand what he wrote? Especially since it was clear? And you still don't have to continue the conversation even if you admit that what Clete wrote and what was in the Wiki were the same.

How about you and me hash it out?

 

[Stripe]

Assuming that no evidence indicating that gravity affects space exists, it would certainly be more reasonable to assert that gravity affects planets.

However, evidence exists in the contrary. The 29 of May, 1919, is one example which attests to this

What happened in 1919? :idunno:

as well as the phenomenon known as Red Shift.

:squint: Red-shift is due to things moving at different speeds. How is this evidence that gravity affects space?

Not to mention GPS-- unless GPS devices take relativity into account, they are off by 7 km. You can thank Einstein for your GPS system's accuracy.

I'm sure the mathematical models that have been developed are very helpful and Einstein's work was instrumental in establishing them. But a GPS works by means of a signal and the deviation of that signal. How is this evidence that gravity affects space when it is the signal we are reading?

Relativity does not deal with mathematical constructs; it deals with the nature of the universe, though obviously plenty of math is involved.

There is no reason to accept this just as there is no reason to believe there are 2/3rds of certain countable nouns walking around out there.

It doesn't, but you are putting the cart before the horse. It proves that Newtonian physics is, at least in part, wrong. Gravity affects actual space to the point that even close to home, astronauts must take relativity into effect.

Or gravity affects the tools the use to measure space. Either way the adjustment calculations will be exactly the same. There is no practical difference between assuming gravity affects space and assuming gravity affects the instruments that measure space. The only difference is that assuming that gravity affects physical things is a testable assertion.

They do exist, and yes. But no one has been able to explain or predict what they are or how they are created without relativity.

It is a mathematical construct of great usefulness, yes... Which we see at work in every day life.

Kids at school learn that families have an average of 2.4 children. Does that mean they would be justified in thinking that there are fractions of children walking around out there?

But we do have a means to test, it's called http://en.wikipedia.org/wiki/Gravitational_lens

Gravity affects light. Big deal. :idunno:

Do you have something that shows that gravity affects space?

HINT: The only way you can test the assumption that gravity affects space is to use space to measure gravity. Given that the only way you can measure space is with physical instruments I will always be able to assume that gravity is affecting the instruments.

The assertion that gravity affects space is untestable. The assertion that gravity affects physical things is common sense.

 

[fool]

What happened in 1919? :idunno:

Gravity affects light. Big deal. :idunno:

Do you have something that shows that gravity affects space?

HINT: The only way you can test the assumption that gravity affects space is to use space to measure gravity. Given that the only way you can measure space is with physical instruments I will always be able to assume that gravity is affecting the instruments.

The assertion that gravity affects space is untestable. The assertion that gravity affects physical things is common sense.

Light moves in a straight line right?
So if we see light bending we come to the conclusion that it's moving in a straight line thru bent space.
Yes? No?

 

[Stripe]

May 29, 1919. :thumb:

Eddington's observations did not make Newton wrong, they merely showed that Newton's laws also applied to light. Given that it is light that we use to render Newtonian equations, we are required to make an accommodation for that when high levels of accuracy are required. This accommodation has been named the theory of relativity and was articulated by suggesting that we think of space as "curved" or, more accurately, "curvable". However there is no need to take the mathematical adjustment designed to decrease error and turn it into a physical trait of the universe.

 

[Stripe]

Light moves in a straight line right?

No. Why would you say that when we can show it does not?

So if we see light bending we come to the conclusion that it's moving in a straight line thru bent space.
Yes? No?

No. I would assume that it was being affected by gravity. Why would I need to say that space was being "bent"? How do you bend nothing?

 

[Lighthouse]

So back to Lighthouse and race cars and such.
Now we have established that the guy on the top of the mountain, though he simply walked a mile up the mountain, sat in a chair all day and walked back, has a vastlty different reading on his "odometer" so to speak than the guy that was at the bottom Right?
And this is because while he's sitting up there his "speedometer" is reading higher than his buddy at the bottom even though they are both sitting in chairs looking at each other and they don't seem to be moving farther apart in relation to each other right?

And?

 

[fool]

And?

Ok, so now lets get another tool, a bathroom scale like we weigh ourselves with.
Do you agree that the guy at the top weighs less?

 

[Yorzhik]

How about you and me hash it out?

OK. In short, the velocity of moving through space is negligible compared to the velocity of a gravity well.

Or, in long:

The effect discussed by Bob in his article has nothing to do with how fast the one is going verses the other, it has to do with how deep in the gravity well one is vs. the other. Relativistically speaking being nearer a strong source of gravity vs. someone else is identical to having a greater velocity than someone else.

Having said that, if the mountain was big enough the person at the top would in fact be traveling faster enough to cancel out the effects of the gravity well. That is to say that the guy at the base would be moving slower through time (according to Relativity) because of the gravity well but the guy at the top would be going slower because of his increased speed relative to the guy at the base and if the mountain was tall enough or the gravity well weak enough the two could cancel each other out but it would have to be one hell of a tall mountain. And I suppose that since we are exaggerating the effects of Relativity for the sake of discussion you could postulate such a thing but the point here is that the increased speed because of the increased distance from the center of the Earth's rotation isn't the issue being discussed in Bob's article and so while the answer to your question is an affirmative, it is also irrelevant.

Resting in Him,
Clete

Or, said another way:

[edit] Velocity and gravitational time dilation combined-effect tests
Hafele and Keating, in 1971, flew caesium atomic clocks east and west around the Earth in commercial airliners, to compare the elapsed time against that of a clock that remained at the US Naval Observatory. Two opposite effects came into play. The clocks were expected to age more quickly (show a larger elapsed time) than the reference clock, since they were in a higher (weaker) gravitational potential for most of the trip (c.f. Pound, Rebka). But also, contrastingly, the moving clocks were expected to age more slowly because of the speed of their travel. The gravitational effect was the larger, and the clocks suffered a net gain in elapsed time. To within experimental error, the net gain was consistent with the difference between the predicted gravitational gain and the predicted velocity time loss. In 2005, the National Physical Laboratory in the United Kingdom reported their limited replication of this experiment.[2] The NPL experiment differed from the original in that the caesium clocks were sent on a shorter trip (London–Washington D.C. return), but the clocks were more accurate. The reported results are within 4% of the predictions of relativity.

 

[Lighthouse]

Ok, so now lets get another tool, a bathroom scale like we weigh ourselves with.
Do you agree that the guy at the top weighs less?

The less gravity the less force, so the weight will not be the same, while the mass will be.

This has no relation to time.

 

[Johnny]

For the "it's just clocks" crowd: What sorts of clocks are affected by relativity (either general or special)? What sorts of clocks are immune?

 

[fool]

The less gravity the less force, so the weight will not be the same, while the mass will be.

This has no relation to time.

So would you say that gravity dosen't effect weight, it effects scales?

 

[fool]

For the "it's just clocks" crowd: What sorts of clocks are affected by relativity (either general or special)? What sorts of clocks are immune?

They may actually be an "it's just scales" crowd.
We'll see.

 

[Stripe]

For the "it's just clocks" crowd: What sorts of clocks are affected by relativity (either general or special)? What sorts of clocks are immune?

Clocks are physical things which are affected by forces that affect physical things. Clocks are affected, for example, by gravity, velocity, temperature, pressure and magnetic fields.

Relativity is a mathematical construct designed to calculate how things will move through non-physical space by granting space an imaginary attribute called "curvature". So, even if you don't agree with everything else, I hope you'll agree that relativity does not affect any clocks.

 

[Andrew Lee]

Just a few thoughts that I'd like to add to this thread. Firstly, time is both absolute and relative, the latter resides within the former. Secondly, space is not nothing, the universe is exclusive of vacuum. Thirdly, time resides within consciousness only.

 

[Johnny]

Clocks are physical things which are affected by forces that affect physical things. Clocks are affected, for example, by gravity, velocity, temperature, pressure and magnetic fields.

I agree. However, these forces to not affect different clocks uniformly. In other words, a wall clock, a digital clock, and a water clock will all be affected differently by the same change in gravity. For the record, you should remove velocity from your list since it exerts no physical force.

Relativity is a mathematical construct designed to calculate how things will move through non-physical space by granting space an imaginary attribute called "curvature".

Why have we concluded that it is imaginary? Math is an abstraction of reality. If it makes testable predictions which have been verified through experiment, at what point do we say this does not actually represent reality?

So, even if you don't agree with everything else, I hope you'll agree that relativity does not affect any clocks.

Then what is affecting clocks uniformly at a given velocity? In other words, an atomic clock and a decay-based clock will be affected to the exact same degree, despite the fact they rely on completely different mechanisms for keeping time. Do you have an explanation as to what's going on here?

And one final question for you: Is the speed of light constant regardless of your velocity?

 

[Stripe]

Why have you decided to start talking to me again?

I agree. However, these forces to not affect different clocks uniformly. In other words, a wall clock, a digital clock, and a water clock will all be affected differently by the same change in gravity.

So? For every case we are capable of making adjustments to account for those changes in degree of effect. With an atomic clock most of the variables are removed, but the effects of gravity and velocity cannot be removed.

For the record, you should remove velocity from your list since it exerts no physical force.

Why? There are numerous observations we can point to that show velocity does affect clocks.

Why have we concluded that it is imaginary?

We haven't. I have.

Math is an abstraction of reality. If it makes testable predictions which have been verified through experiment, at what point do we say this does not actually represent reality? This is the classic scientific realism vs instrumentalism debate, which I am quite certain you and I will not resolve here and now

When there is a perfectly reasonable physical explanation for an observation I would go with the physical explanation rather than the non-physical one.

Then what is affecting clocks uniformly at a given velocity?

Gravity.

In other words, an atomic clock and a decay-based clock will be affected to the exact same degree, despite the fact they rely on completely different mechanisms for keeping time. Do you have an explanation as to what's going on here?

Really? Do you have the numbers on that?

Or are the two clocks simply adjusted according to their own variation?

And one final question for you: Is the speed of light constant regardless of your velocity?

I don't know. Relativity says that it is, but if relativity is another word for timekeeping error then perhaps not.

 

[Lighthouse]

For the "it's just clocks" crowd: What sorts of clocks are affected by relativity (either general or special)? What sorts of clocks are immune?

We didn't say the clocks are effected by relativity. It's your side who says they are.

We said they are effected by gravity.

So would you say that gravity dosen't effect weight, it effects scales?

Nope. It effects weight, because weight is based on gravity. Your weight is what it is because of the force with which gravity pulls you down. Which is how it also effects clocks.

 

[Johnny]

Why have you decided to start talking to me again?

5 days off stripe was sufficient recovery time.

For every case we are capable of making adjustments to account for those changes in degree of effect.

Exactly. For each individual clock, a unique correction factor must be used because each clock is affected differently (even when they are subject to the same changing variable). This is not the case with relativity. Every clock is affected to the same degree.

Then what is affecting clocks uniformly at a given velocity?

Gravity.

Gravity has nothing to do with special relativity (to which I am clearly referring). The effect is still present even when gravity is accounted for, or in zero gravity situations.

In other words, an atomic clock and a decay-based clock will be affected to the exact same degree, despite the fact they rely on completely different mechanisms for keeping time. Do you have an explanation as to what's going on here?

Really? Do you have the numbers on that?

Or are the two clocks simply adjusted according to their own variation.

Two different clocks will experience the exact same time dilating effects under the same conditions, regardless of their mechanism of action of the clocks. The lorentz transformation describes the degree in which all clocks will measure time at a given velocity, not just atomic clocks. This is demonstrated by the numerous studies calculating muon decay, pion lifetimes, kaon lifetimes, atomic resonance frequencies, as well as a number of other techniques which, despite the varying mechanism for keeping time, all show the changes in time plotted along the same lortenz curve. In other words, at the same velocities, two clocks operating by different mechanisms demonstrate the exact same change in time. This is in contrast to the clock examples you provided earlier, which are all simply reduced to a physical force acting on a mechanical clock thereby decreasing its accuracy.

And one final question for you: Is the speed of light constant regardless of your velocity?

I don't know. Relativity says that it is, but if relativity is another word for timekeeping error then perhaps not.

The invariance of the speed of light is a postulate on which special relativity rests, it isn't a product of special relativity. And anyways, isn't that something we can measure? We can find luminous objects in space we are moving away from at extremely high velocities. Why not just measure the speed of light incoming from those objects? And given modern technologies, can't we measure changes in the speed of light in the lab?

Do you think you think generations of brilliant physicists have neglected to consider your objections?