Time Travel to the future a Fact?

[swansont]

Boys this is all very interesting' date=' but I really think that when 5 minutes goes by here on Earth, 5 minutes goes by everywhere else in the universe.

 

It might not seem like 5 minutes, and certain mechanical measuring devices may read different, but 5 minutes has passed just the same.[/quote']

 

If this were a matter of opinion, I'd say you were entitled to your opinion. But this is a matter of science, and the evidence doesn't support your viewpoint.

[Johnny5]

Then how do you explain light travelling at the same speed relative to an observer of any velocity?

 

Are you certain that is true?

[Johnny5]

I'm saying the gravitational force is not causing a mechanical effect that slows the clock down. If it were, you'd expect different clocks to be affected differently.

 

Ok, you are saying that the gravitational force is not causing a mechanical effect that slows down the clock. I disagree. Now what?

 

There has got to be some kind of gravitational effect on the innards of any clock.

 

They (the interior parts of the clock) are being pulled down, this increases friction.

[Cadmus]

Well, then I got ripped off. We never covered "negative traumatic experiences" when I was taking physics in school. Is that supposed to be part of mechanics, E&M, atomic physics or nuclear?

Is that all you can see in my example? Perhaps you were ripped off at school. Here is your chance to rectify that. Don't waste it.

[Cadmus]

Boys this is all very interesting' date=' but I really think that when 5 minutes goes by here on Earth, 5 minutes goes by everywhere else in the universe.

 

It might not seem like 5 minutes, and certain mechanical measuring devices may read different, but 5 minutes has passed just the same.[/quote']That is fine. There is certainly no requirement that you accept the notion of relativity, or even science for that matter. I wonder, however, if you have no interest in relativity, why do you even bother speaking about the entire universe?

[swansont]

Ok' date=' you are saying that the gravitational force is not causing a mechanical effect that slows down the clock. I disagree. Now what?

 

There has got to be some kind of gravitational effect on the innards of any clock.

 

They (the interior parts of the clock) are being pulled down, this increases friction.[/quote']

 

What friction exists in an atom, and in electronics? Especially that would be consistently affected, regardless of the type of clock, but dependent on the strength of g and on the speed? And clocks that are in orbit - i.e. freefall, so they seem weightless - are affected as well as clocks in a ballistic trajectory, or clocks at different elevations on earth.

[swansont]

Is that all you can see in my example? Perhaps you were ripped off at school. Here is your chance to rectify that. Don't waste it.

 

Emotional state has absolutely nothing to do with the actual passage of time. That's all perception. If it were an actual effect on time, the watch strapped to the person's wrist would have to tick at a different rate.

[Cadmus]

Emotional state has absolutely nothing to do with the actual passage of time. That's all perception. If it were an actual effect on time, the watch strapped to the person's wrist would have to tick at a different rate.

I think that you are being somewhat limiting in the way that you frame this.

 

In the sense of relativity, clock time is irrelevant to how fast time passes. When one year of clock time passes, that does not mean that the exact same amount of time has passed for every person on earth, except in a non-relativistic, objective manner of thinking.

[swansont]

I think that you are being somewhat limiting in the way that you frame this.

 

In the sense of relativity' date=' clock time is irrelevant to how fast time passes. When one year of clock time passes, that does not mean that the exact same amount of time has passed for every person on earth, except in a non-relativistic, objective manner of thinking.[/quote']

 

You must be using a non-standard definition of "relativistic." Time on the geoid runs at the same rate, everywhere on earth.

[Cadmus]

You must be using a non-standard definition of "relativistic." Time on the geoid runs at the same rate, everywhere on earth.

I think that it must be you who is using a non-standard use of relativity. Time is the same nowhere, certainly not everywhere on earth. You must be speaking in terms of measuring time using an objective, third-party device, rather than in terms of the objects whose time is being considered.

[swansont]

I think that it must be you who is using a non-standard use of relativity. Time is the same nowhere, certainly not everywhere on earth. You must be speaking in terms of measuring time using an objective, third-party device, rather than in terms of the objects whose time is being considered.

 

Clocks measure the passage of time. If time passase at a different rate somewhere, it must be measurable by a clock. Relativity has two terms in it that affect time: a kinetic potential and a gravitational potential. These cancel on the geoid. Any other effect you think affects the passage of time is not part of relativity.

 

"in terms of the objects whose time is being considered" ? I have no idea what that means.

[Sayonara]

I think that it must be you who is using a non-standard use of relativity.

I think that's somewhat unlikely tbh.

[syntax252]

Then how do you explain light travelling at the same speed relative to an observer of any velocity?

 

You will have to elaborate on that one a little bit.

[syntax252]

If this were a matter of opinion, I'd say you were entitled to your opinion. But this is a matter of science, and the evidence doesn't support your viewpoint.

 

Perhaps, but evidence can be misinterpreted.

 

Does the Sun come up because the rooster crows? Or is it the other way around.

[syntax252]

That is fine. There is certainly no requirement that you accept the notion of relativity, or even science for that matter. I wonder, however, if you have no interest in relativity, why do you even bother speaking about the entire universe?

Oh, I have an interest in relativity all right. I just do not feel compelled to accept something as absolute fact until I can understand why it is fact and all the other questions that this fact creats are answered.

[Dave]

I think a better place for this thread would be relativity, so I'll move it there now.

[Ophiolite]

You will have to elaborate on that one a little bit.

Light was thought to be a wave, analagous to sound waves. Sound waves were known to be waves of compression within some medium, e.g. air. What was the medium that light operated in? This was postulated to be the ether, a rather ill defined medium that existed only to transmit light.

Michelson established the speed of light in the 1870s. It was then realised that by measuring the speed of light in different directions it would be possible to determine the velocity of the Earth relative to the ether. This experiment, the famous Michelson-Morley experiment was conducted and, remarkably, revealed no difference of light speed in different directions.

It was this well defined observation, in part, that led Einstein to declare that the speed of a light was a constant, regardless of the movement of the observer.

Is that sufficient elaboration?

[swansont]

Light was thought to be a wave' date=' analagous to sound waves. Sound waves were known to be waves of compression within some medium, e.g. air. What was the medium that light operated in? This was postulated to be the ether, a rather ill defined medium that existed only to transmit light.

Michelson established the speed of light in the 1870s. It was then realised that by measuring the speed of light in different directions it would be possible to determine the velocity of the Earth relative to the ether. This experiment, the famous Michelson-Morley experiment was conducted and, remarkably, revealed [b']no [/b]difference of light speed in different directions.

It was this well defined observation, in part, that led Einstein to declare that the speed of a light was a constant, regardless of the movement of the observer.

Is that sufficient elaboration?

 

More precisely, the M-M experiment established that we were not moving through the ether. (stellar aberration measurements had already established that the earth could not be stationary in the ether) It was not a direct measurement of the speed of light, it was an interference measurement to see if the light had slowed down in the direction of the earth's motion vs a perpendicular direction. So if we are simultaneously not stationary and not moving with respect to the ether, the conclusion is there is no ether.

 

Einstein also had at his disposal Maxwell's equations that showed that, for electromagnetic phenomena, c had to be constant, but up until the M-M experiment it was assumed that it was constant with respect to the ether. SR is really just the next step that falls out of that

[Cadmus]

Clocks measure the passage of time.

Yes, but time is not what a clock measures.

 

If time passase at a different rate somewhere, it must be measurable by a clock.

I disagree.

 

 

Clocks measure their own passgage through time. They do not demonstrate any relationship to how other objects pass through time, except in an objective sense, which is the least useful sense from the perspective of relativity.

[Cadmus]

I just do not feel compelled to accept something as absolute fact until I can understand why it is fact and all the other questions that this fact creats are answered.

Let me give some advice. I recommend that you never, ever accept anything in science as absolute fact. Now, wasn't that easy? Science is not about fact, and it is always open to analysis and revsion.

 

While you do not accept it as absolute fact, which is a good thing, surely you must be aware that there is no chance that relativity could ever answer all questions, and for you to understand all of the questions that it attemps to answer is also not realsitc. Are you suggesting that you will ignore the theory unless and until you find it to be perfect?

[syntax252]

Let me give some advice. I recommend that you never, ever accept anything in science as absolute fact. Now, wasn't that easy? Science is not about fact, and it is always open to analysis and revsion.

 

Yes, it was easy. It is also close to what I have been doing for the past 50 years or so.

 

 

While you do not accept it as absolute fact, which is a good thing, surely you must be aware that there is no chance that relativity could ever answer all questions, and for you to understand all of the questions that it attemps to answer is also not realsitc. Are you suggesting that you will ignore the theory unless and until you find it to be perfect?

I am suggesting that if I take on a position of "oh, why yes, of course time is mallable, because Einstien said so" that I would be little more than a parrot, or a mechanical recording device that simply repeated everything that I was told regardless of whether I could understand it or not.

 

IMO, we already have plenty of those in the world.....

[syntax252]

Light was thought to be a wave' date=' analagous to sound waves. Sound waves were known to be waves of compression within some medium, e.g. air. What was the medium that light operated in? This was postulated to be the ether, a rather ill defined medium that existed only to transmit light.

Michelson established the speed of light in the 1870s. It was then realised that by measuring the speed of light in different directions it would be possible to determine the velocity of the Earth relative to the ether. This experiment, the famous Michelson-Morley experiment was conducted and, remarkably, revealed [b']no [/b]difference of light speed in different directions.

It was this well defined observation, in part, that led Einstein to declare that the speed of a light was a constant, regardless of the movement of the observer.

Is that sufficient elaboration?

 

Well, not quite.

 

How did they determine that there was no difference?

[swansont]

Clocks measure their own passgage through time. They do not demonstrate any relationship to how other objects pass through time, except in an objective sense, which is the least useful sense from the perspective of relativity.

 

I am reminded of the Wolfgang Pauli quote: "This isn't right. It isn't even wrong."

[swansont]

I am suggesting that if I take on a position of "oh' date=' why yes, of course time is mallable, because Einstien said so" that I would be little more than a parrot, or a mechanical recording device that simply repeated everything that I was told regardless of whether I could understand it or not.

[/quote']

 

I don't think anyone has suggested you do this. Saying you don't yet understand the theory and supporting evidence is different, however, than saying that time isn't malleable.

[swansont]

How did they determine that there was no difference?

 

They split up a beam and sent it in perpendicular directions and the recombined the beams. If the speed had changed, there would be a particular interference pattern that depends on the speed change. Standard interferometry.