about Bob's article on absolute or relative time

[Lighthouse]

From Brittanica:

Soon after Albert Einstein’s general theory of relativity was published in 1916, scientists set to conducting a number of experimental tests to verify or disprove various predictions of the theory. One prediction was that the dark (absorption) lines known as Fraunhofer lines in the spectrum of sunlight should be redshifted (i.e., shifted toward longer wavelengths) by a precise amount because of the Sun’s gravitational field. Astronomers failed initially to find this shift, so in 1918 the validity of the general theory was still in some doubt.

The general theory also predicted that a ray of light emanating from a distant star and passing near the Sun should be deflected a measurable amount by the Sun’s gravity. If the ray just grazes the edge of the Sun, the angular deflection should be 1.75 arc seconds, and the deflection should decrease in proportion to the distance of the ray from the Sun’s edge. (For comparison, the average solar diameter is 1,922 arc seconds.) Einstein suggested that astronomers should observe this effect at a total eclipse as another test of his theory.

British astronomers, including Arthur Eddington, took up the challenge. They organized two expeditions to observe the five minutes of totality afforded by the eclipse of May 29, 1919, one in Sobral, Braz., and the other on the island of Príncipe, off the African coast. From Sobral the astronomers obtained a series of photographs on glass plates of the stars around the Sun at mid-totality. The expedition also photographed the same stars that had appeared during the eclipse but without the presence of the Sun. By comparing the relative positions of the stars on the two sets of plates, the astronomers obtained a figure of 1.98 arc seconds for the deflection of starlight at the edge of the solar disk. The expedition to Príncipe, led by Eddington, encountered clouds during the eclipse and was able to photograph only four stars on five plates. From these, Eddington derived an estimate of 1.61 arc seconds for the deflection at the edge of the Sun. The combined results from the two expeditions were close enough to the predicted 1.75 arc seconds to lend support to Einstein’s theory but not to establish it unconditionally. Nevertheless, they had tremendous popular appeal and helped establish Einstein as one of the foremost physicists of his time.

And still nothing to verify that time is relative.

You do realize that's the specific part of the theory we are debating, correct?

 

[Stripe]

You may hold the opinion that you do about this - that is your right. But it is clear that you stand against the overwhelming majority of trained physicists who will hold that the space twin will come back "younger" than the earthbound twin.

So? :idunno:

From Brittanica:

Soon after Albert Einstein’s general theory of relativity was published in 1916, scientists set to conducting a number of experimental tests to verify or disprove various predictions of the theory. One prediction was that the dark (absorption) lines known as Fraunhofer lines in the spectrum of sunlight should be redshifted (i.e., shifted toward longer wavelengths) by a precise amount because of the Sun’s gravitational field. Astronomers failed initially to find this shift, so in 1918 the validity of the general theory was still in some doubt.

The general theory also predicted that a ray of light emanating from a distant star and passing near the Sun should be deflected a measurable amount by the Sun’s gravity. If the ray just grazes the edge of the Sun, the angular deflection should be 1.75 arc seconds, and the deflection should decrease in proportion to the distance of the ray from the Sun’s edge. (For comparison, the average solar diameter is 1,922 arc seconds.) Einstein suggested that astronomers should observe this effect at a total eclipse as another test of his theory.

British astronomers, including Arthur Eddington, took up the challenge. They organized two expeditions to observe the five minutes of totality afforded by the eclipse of May 29, 1919, one in Sobral, Braz., and the other on the island of Príncipe, off the African coast. From Sobral the astronomers obtained a series of photographs on glass plates of the stars around the Sun at mid-totality. The expedition also photographed the same stars that had appeared during the eclipse but without the presence of the Sun. By comparing the relative positions of the stars on the two sets of plates, the astronomers obtained a figure of 1.98 arc seconds for the deflection of starlight at the edge of the solar disk. The expedition to Príncipe, led by Eddington, encountered clouds during the eclipse and was able to photograph only four stars on five plates. From these, Eddington derived an estimate of 1.61 arc seconds for the deflection at the edge of the Sun. The combined results from the two expeditions were close enough to the predicted 1.75 arc seconds to lend support to Einstein’s theory but not to establish it unconditionally. Nevertheless, they had tremendous popular appeal and helped establish Einstein as one of the foremost physicists of his time.

All your observations first require the assumption that gravity and velocity affect time. The same observations could be used to support the idea that gravity and velocity affect the devices measuring the time.

Assuming that gravity affects clocks has the advantage of being testable. However there is no way to measure time without using a clock.

Perhaps relativity is correct, but, given that the theory is untestable, it is not science.

 

[pozzolane]

"I believe stuff without any proof."
-pozzolane

"I don't listen to what other people are saying or implying, so I just make assumptions because I roll like that. I have a shirt that points up that reads "I'm with stupid". It's my favorite shirt."

-Lighthouse

And you consider the fact that a clock acts differently in differing levels of gravity to be enough evidence to believe time dilates?

Time dilation is a phenomena because time is relative. And there is a a fair bit of evidence suggesting it's validity. The fact that you think the only thing (as stripe calls us now) "relativists" use for evidence in support of time dilation are "clocks (that) act differently in differing levels of gravity", only shows how grossly ignorant you are on the subject and how inappropriate it is that you try to engage in such a level of conversation in which you don't intend to learn, but assert.

And if there is no proof in science, why is anything considered a scientific fact?

Nothing is considered a fact in science. The moment science deals with "facts" is the moment it becomes dogmatic.

That doesn't falsify anything. There is no way to falsify time dilation if we are also supposed to be affected.

Yes there is. That experiment with the atomic clocks on the airplane circling the globe would have falsified time dilation had the clocks still been in perfect unison.

 

[Stripe]

Here's the point. Two clocks show different times at different altitudes.

The majority assumes relativity, records the difference and uses it to calibrate the clocks for any gravitational change.

Pastor Enyart's article states that it is just as valid to assume gravity affected the clock.

This alternative assumption does not remove the ability to do the exact same calculations and it has the advantage of being testable.

 

[Lighthouse]

"I don't listen to what other people are saying or implying, so I just make assumptions because I roll like that. I have a shirt that points up that reads "I'm with stupid". It's my favorite shirt."

-Lighthouse

Time dilation is a phenomena because time is relative. And there is a a fair bit of evidence suggesting it's validity. The fact that you think the only thing (as stripe calls us now) "relativists" use for evidence in support of time dilation are "clocks (that) act differently in differing levels of gravity", only shows how grossly ignorant you are on the subject and how inappropriate it is that you try to engage in such a level of conversation in which you don't intend to learn, but assert.

Nothing is considered a fact in science. The moment science deals with "facts" is the moment it becomes dogmatic.

Yes there is. That experiment with the atomic clocks on the airplane circling the globe would have falsified time dilation had the clocks still been in perfect unison.

None of this does anything except to show that the clocks were effected. It does not show that time itself acts differently. And the clocks were not going to remain in perfect unison. Not with that significant change in gravity.

What I'd really like to know is if the clocks synced back up when they came back to the same gravitational field.:think:

Also, if the clock thing isn't all you have, give us somethign else...

 

[eveningsky339]

And still nothing to verify that time is relative.

You do realize that's the specific part of the theory we are debating, correct?

Your IQ seems to drop a little every day. :doh:

 

[pozzolane]

The basis of the issue is, no matter how accurate or helpful a mathematical model is, the name of such a model does not impose any physical reality upon the universe.

And here is where you expose your stupidity and arrogance. You start from the assumption that science is in the business of satisfying what you deem is "reality" solely based on your limited capacity to observe and think critically. WRONG.

Relativity does no such thing as force or "impose" a physical reality upon the universe. Rather, it nicely describes the physical reality of said universe.

I've never before had such misfortune as to communicate with someone who wishes to be so dogmatic that they try to enforce it upon the very tool of discovery that by definition cannot be such a thing. No wonder you cannot understand what has been already neatly described and shown to you. You are hopeless, and any scientific discussion with you is a complete waste of time.

 

[Lighthouse]

Your IQ seems to drop a little every day. :doh:

Not according to the tests I underwent in school.

 

[Johnny]

Watch this

Hopefully this will give us all some common terms on which to speak. That video summarizes time dilation very well. Maybe one of you anti-relativity clowns would be adventurous enough to offer up some rebuttal in terms of this video.

 

[Memento Mori]

Hate to open up this can o' worms but

Distances also change as you approach the speed of light!

 

[Lighthouse]

Hate to open up this can o' worms but

Distances also change as you approach the speed of light!

Would you like to elaborate?

 

[Memento Mori]

Would you like to elaborate?

The perceived distance required to travel from A to B changes. As you approach the speed of light, distances shorten... To a photon (which is traveling at the speed of light), it seems to cover 0 distance.

I really wish I could remember those equations.

 

[Johnny]

Here's another excellent video that starts to go into length contraction:

Time Dilation and Length Contraction

That's probably the best video that I've found. Sort of cheesy animations, but it really explains time dilation very well. The relativity series is 6 videos long, and I highly highly recommend watching all 6. If you start at part 1, you can work your way through the videos in order. At the end of each video, you'll see a link to the next video in the series.

 

[Memento Mori]

Oh, and the best proof of Relativity is muons charged in the upper atmosphere.

Unfortunately I don't have a calculator handy and I'm getting tired. So, I'll slough my work onto Johnny or someone else if they know this whole experiment.

 

[Stripe]

Hopefully this will give us all some common terms on which to speak. That video summarizes time dilation very well. Maybe one of you anti-relativity clowns would be adventurous enough to offer up some rebuttal in terms of this video.

This has nothing to do with the opening post (unless you think a change in gravity is of no impact).

Have you got anything that deals with the example being discussed?

 

[chair]

I find this whole discussion both enlightening and perturbing.

A generation of scientists develops new theories about the way Nature works. The theories explain experimental results that earlier theories could not handle well. The new theories make accurate predictions.

So, what happens?

A bunch of guys who don't know the math, aren't aware of many the experiments that were done, nor the details of the experiments that they are aware of, think that it "doesn't make sense".

Why?

In this case, it doesn't even present a direct challenge to the Bible.

It seems that there is a basic mistrust of Science in general, combined with the hubris of thinking they have the knowledge and ability to judge things they know almost nothing about.

I have a PhD in one of the Physical Sciences. Physical Chemistry, to be exact. I am quite aware that I do not know very much about relativity. I wouldn't dream of being critical of the theory without investing some serious study of the matter. And I know how science works well enough to know that well- established theories are usually well-established for good reason.

I guess ignorance and arrogance can take the place of knowledge for some people.

Sad. Even frightening.

 

[Stripe]

I find this whole discussion both enlightening and perturbing.

A generation of scientists develops new theories about the way Nature works. The theories explain experimental results that earlier theories could not handle well. The new theories make accurate predictions.

So, what happens?

A bunch of guys who don't know the math, aren't aware of many the experiments that were done, nor the details of the experiments that they are aware of, think that it "doesn't make sense".

Why?

In this case, it doesn't even present a direct challenge to the Bible.

It seems that there is a basic mistrust of Science in general, combined with the hubris of thinking they have the knowledge and ability to judge things they know almost nothing about.

I have a PhD in one of the Physical Sciences. Physical Chemistry, to be exact. I am quite aware that I do not know very much about relativity. I wouldn't dream of being critical of the theory without investing some serious study of the matter. And I know how science works well enough to know that well- established theories are usually well-established for good reason.

I guess ignorance and arrogance can take the place of knowledge for some people.

Sad. Even frightening.

Oh noes! These people are going to destroy us all!

 

[andrewh]

Relativity does no such thing as force or "impose" a physical reality upon the universe. Rather, it nicely describes the physical reality of said universe.

You are, of course, entirely correct. It is a shame that more time is not spent in high school explaining precisely what a scientific theory fundamentally is. A scientific theory is a model that makes predictions - it is thus a description that tries to order and make sense of myriads of specific observations about the real world out there.

General (and special) relativity are precisely this - models of the real world "out there" (or at least models of "part" of it). And these models make specific predictions about what is expected to happen in a certain experiment if the theory is correct.

 

[Johnny]

This has nothing to do with the opening post (unless you think a change in gravity is of no impact).

Have you got anything that deals with the example being discussed?

Special and general relativity both deal with the relativity of time, which is what we are discussing. "Is time absolute or relative?" I think most people find special relativity much easier to discuss in every day terms, whereas general relativity tends to be more abstract.

However, there is a conceptual connection can be made between special and general relativity. In special relativity (the previous videos), observers at rest observe the clocks of objects in motion ticking slow. This is because from the standpoint of the observer at rest, light has more space to travel through, and since light's speed through space is constant, time appears to slow down for the observer in motion.

Connect this with general relativity which says that gravity is actually the curvature of space. Thus, similar to high velocity, in high gravitational fields, light's path through space isn't straight. And in just like with high velocity, clocks in different gravitational fields will note time passing differently because the geometry of space will be different for each observer. This is all shown with differential geometry, which is why special relativity is a bit easier to grasp.

General Relativity Part 1

General Relativity Part 2

 

[Stripe]

Special and general relativity both deal with the relativity of time, which is what we are discussing. "Is time absolute or relative?" I think most people find special relativity much easier to discuss in every day terms, whereas general relativity tends to be more abstract.

However, there is a conceptual connection can be made between special and general relativity. In special relativity (the previous videos), observers at rest observe the clocks of objects in motion ticking slow. This is because from the standpoint of the observer at rest, light has more space to travel through, and since light's speed through space is constant, time appears to slow down for the observer in motion.

Connect this with general relativity which says that gravity is actually the curvature of space. Thus, similar to high velocity, in high gravitational fields, light's path through space isn't straight. And in just like with high velocity, clocks in different gravitational fields will note time passing differently because the geometry of space will be different for each observer. This is all shown with differential geometry, which is why special relativity is a bit easier to grasp.

OK.

I find it much more reasonable to assume that gravity is affecting the physical attributes of the instruments we are reading than to assume space is "curved".

Can you tell me how my assumption will not cater for exactly the same reliability in mathematical calculations?