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## Light

Hello:
I'm new to this and I'm not a pro scientist so please excuse me.
Can anybody please give me a good analogy for visualizing how the speed of light will always travel at a constant speed no matter how fast you are traveling? Though I understand the consequences of both Special and General Relativity this concept just has'nt sunk in. Thank You very much.

2. Welcome.

The truth is that visualising this is tricky as it all depends on giving up a subconsious concept that we all hold dear: an ethereal frame of reference. After the M-M experiment, Lorentz derived his translations mathematically. But, to explain the results physically, he still made use of the quintessential ether. He postulated that as objects move through the ether, their length shrinks and their time dilates. Einstein did away with the ether and said that everything is relative.

It is not an attractive prospect. We like the idea of an ethereal frame of reference. It gives us a feeling of security, knowing we can define our exact position, time, etc. So, when we consider that things seem different in different frames, and that their is no way to determine which is the "true" way it should look, is a little disorienting.

Consider: You observe a couple of spaceships moving relative to you, exchanging messages via flashes of light in the direction of travel. You see the light travel at c and are happy. They are travelling at a certain speed, v and as such, you perceive them travelling c-v slower than the light.

However, from the perspective of the people on the ships, the light is travelling at c as well, when if we were Newtonian, we would expect it to be c-v. How can they measure the same speed of light? The answer is that while you think they should measure c-v for the speed of light, you observe the clock on their ship and see that it is ticking more slowly that in should. So one of their seconds is longer than yours, and hence the time they'll measure for the light to travel between ships is less than the time you would measure it, because their clocks are running slow. Since v=s/t, and the value of t onboard the ships is shorter than from your position, they calculate the speed relative to them to be faster than the speed you think they should measure. The maths surrounding these translations make it such that the faster speed is in fact c.

The concepts are pretty abstract because in everyday life, we are capable of establishing a reasonable "absolute" coordinate system.

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Glom,
I understand. Thanks. There is nothing bad about being a RAF pilot.

4. Originally Posted by Russell
I'm aware of that. That's the problem.

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Please don't take offense, I work RAF and Royal Marines down here in Naples and love it. Like I said before, I'm new to this site so you have to excuse me. I have more questions than answers and look at this site as a good forum for learning. I'm getting ready to tackle "The Meaning of Relativity" and I'm quite scared of the math. I've read many books on the subject but never anything on the mechanics. So I may need help. Gotta get to work, thanks.

6. The topics can be very heavy. I often don't have the attention span to read them properly.

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Originally Posted by Glom
Consider: You observe a couple of spaceships moving relative to you, exchanging messages via flashes of light in the direction of travel. You see the light travel at c and are happy. They are travelling at a certain speed, v and as such, you perceive them travelling c-v slower than the light.

However, from the perspective of the people on the ships, the light is travelling at c as well, when if we were Newtonian, we would expect it to be c-v. How can they measure the same speed of light? The answer is that while you think they should measure c-v for the speed of light, you observe the clock on their ship and see that it is ticking more slowly that in should. So one of their seconds is longer than yours, and hence the time they'll measure for the light to travel between ships is less than the time you would measure it, because their clocks are running slow. Since v=s/t, and the value of t onboard the ships is shorter than from your position, they calculate the speed relative to them to be faster than the speed you think they should measure. The maths surrounding these translations make it such that the faster speed is in fact c.
Spacecraft clocks run slow because of their motion? The mainstream sites say that spacecraft clocks speed up when the craft get out of the strong gravitational field that’s near the surface of the earth.

In the Hafele Keating flying clocks experiment, all the clocks’ averaged time change showed an overall speed up, not an overall slowdown.

How can the relative motion of two spacecraft slow down the two clocks in the two different spacecraft? How can “looking” at a clock slow it down?

If you think they are traveling away from a light source and they encounter the light that overtakes them from the rear at c-v, then if their clocks slow down the right amount, that might cause them to think that the light speeded up to c, but what of the light they receive from the front? From a source they are moving toward? If you think they encounter that light at c + v, and if their clocks slow down, then they would see that light from the front traveling much faster than c + v.

Do their clocks slow down for the light coming from the rear and speed up for the light coming from the front?

8. Originally Posted by Sam5
Spacecraft clocks run slow because of their motion? The mainstream sites say that spacecraft clocks speed up when the craft get out of the strong gravitational field that’s near the surface of the earth.

In the Hafele Keating flying clocks experiment, all the clocks’ averaged time change showed an overall speed up, not an overall slowdown.

How can the relative motion of two spacecraft slow down the two clocks in the two different spacecraft? How can “looking” at a clock slow it down?

If you think they are traveling away from a light source and they encounter the light that overtakes them from the rear at c-v, then if their clocks slow down the right amount, that might cause them to think that the light speeded up to c, but what of the light they receive from the front? From a source they are moving toward? If you think they encounter that light at c + v, and if their clocks slow down, then they would see that light from the front traveling much faster than c + v.

Do their clocks slow down for the light coming from the rear and speed up for the light coming from the front?
Did I say anything about Earth or gravitational fields? Your straw man tactics will not work with us. SR is very clearly explained. We don't need yet another thread focusing on your discontent with it. Time dilation is not direction dependant. Only speed dependant. The dilation works the same for both separating and approaching frames.

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Glom,

Well, since I’m so stupid and you are so smart, I hoped you could answer my question. You seem to know all about this stuff. So, if you slow down the clocks of the people on the moving spacecraft so they will see a light beam coming toward them from the rear at the speed of “c” (when it would be c-v if their clocks don’t slow down), then how will they see light coming at them from the front at “c”, since their clock slow-down would seem to cause them to see the oncoming light from the front at a speed of much faster than “c” (since without the clock slow-down the speed would be c + v)?

10. When dealing with relativistic problems like this one, there are three factors that must be borne in mind: Fitzgerald-Lorentz Contraction, time dilation, and the relative nature of simultaneity.

Let’s do a thought-experiment. Tom, Dick and Harry are sitting out in deep space in three spaceships, which are aligned along the x-axis, with Tom to our left, Dick in the middle and Harry to our right. To begin with, they are at rest relative to one another:

TOM--------------------DICK-------------------HARRY

Dick’s ship is sausage-shaped and 300,000 km long. At the stern are two clocks, one on the port side and one on the starboard side. At the bow are two identical clocks. Dick has a fifth clock in his hand. He stands in the middle of his ship - equidistant from the bow and stern clocks - and sets the fifth clock going. It has been programmed to send out a signal that starts the other clocks. The bow and stern clocks are now synchronized.

Tom sends a light pulse to Dick. As it passes the stern clock on the port side of Dick’s ship, it stops that clock. The pulse then races the length of Dick’s ship and as it passes the bow clock on the port side, it stops that clock too. Dick now examines the two port clocks at his leisure. He notices that the bow clock was stopped precisely one second after the stern clock. So, he calculates, the light must have been travelling at 300,000 kps (distance = speed x time) = c.

The experiment is repeated, but this time it is Harry who sends out a pulse and it’s the starboard clocks which are stopped. Naturally, the result is the same.

Okay. That was easy. Now comes the tricky part. Let’s say that at the start of the experiment, Tom and Harry are at rest relative to each other, but Dick is moving towards Harry at 150,000 kps. Dick’s clocks are all set at zero and are not yet going. As far as Dick is concerned, he’s the stationary frame of reference and it’s Tom and Harry who are moving to our left at 150,000 kps. Dick stands in the middle of his ship, equidistant from the four stern and bow clocks, and sets them all going at the same moment, just as before, by sending them a signal from his fifth clock. From his point of view, the four clocks are now synchronized.

But - and this is the crucial point - from Tom and Harry’s point of view, the clocks are not synchronized at all. Since Dick was moving towards Harry when his fifth clock sent out the signal, that signal had to chase after the bow clocks, but was met by the stern clocks. So the stern clocks would have received the signal first and would have started ticking before the bow clocks.

But how long before? Let’s work it out from Tom’s point of view. Remember, in Tom’s stationary frame, Dick’s ship is no longer 300,000 km long. Fitzgerald-Lorentz contraction means it is only 300,000/Gamma km long, where Gamma = 1/√(1 - v²/c²). Also remember that Dick’s clocks (once they’ve started) will be ticking more slowly than Tom’s clocks by that same Gamma factor. Now, Dick’s speed, v, is 150,000 kps, so Gamma = 1.1547005…, and Gamma² = 4/3.

From Tom’s point of view, the signal from the fifth clock should have been catching up with the bow clocks at 150,000 kps. The distance it had to traverse was 150,000/Gamma. So the undilated time it took was 1/Gamma. The dilated time is 1/Gamma² = ¾ seconds. In other words, the fifth clock in Dick’s hand will tick ¾ seconds before the bow clocks are started.

Now from Tom’s point of view, the signal from the fifth clock should have been approaching the stern clocks at 450,000 kps. The distance is again 150,000/Gamma, so it should take it 150,000/(Gamma²x450,000) dilated seconds, or ¼ seconds. In other words, by the time the bow clocks receive the signal and start ticking, the stern clocks will have already ticked ½ a second!

So Dick sees the stern and bow clocks as synchronized. But to Tom and Harry, the stern clocks are half a second ahead of the bow clocks.

Now let’s repeat the original experiment. Tom sends out a pulse of light. It passes the stern clock on the port side of Dick’s ship and stops it. Let’s say that the time on that clock at that moment is 0. From Tom’s point of view, the bow clock now reads minus 0.5 seconds. The light pulse races after the bow clock, which is moving towards Harry at 150,000 kps. From Tom’s point of view, the light should be catching the bow clock at 150,000 kps. The distance it must traverse is 300,000/Gamma km. The undilated time it takes to traverse this distance is 2/Gamma. The dilated time it takes is 2/Gamma² = 1.5 seconds. In other words, after the stern clock stops, bow clock ticks for a further 1.5 seconds before it too stops. And since the bow clock read -0.5 when the stern clock stopped, it will read +1 second when it stops.

So when Dick examines the port clocks, he will discover that the light from Tom’s ship took precisely one second to traverse his ship, which is still 300,000 km long as far as he’s concerned. (Since he’s at rest relative to himself, he can detect no Fitzgerald-Lorentz contraction or time dilation.) Therefore the speed at which Tom’s light pulse overtook him was 300,000 kps = c!

Phew! Now let’s see what happens to Harry’s pulse. It rushes towards the oncoming ship. As it passes the bow clock on the starboard side, it stops it. Let’s say that the time on this clock when it stops is 0 seconds. Then from Harry’s point of view, the starboard stern clock reads +0.5 seconds at the moment the bow clock stops. The light pulse races on towards the stern clock. From Harry’s perspective it should be approaching it at 450,000 kps. The distance it must travel is 300,000/Gamma km. The dilated time it takes to cover that distance is 300,000/Gamma²x450,000 = 0.5 seconds. Since the stern clock already read 0.5, it will read +1 when the light pulse stops it.

So when Dick examines the starboard clocks, he will discover that the light from Harry’s ship took precisely one second to traverse the length of his ship: 300,000 km as far as he is concerned. Therefore, the speed at which Harry’s pulse passed his ship was 300,000 kps = c!

QED!

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## Light

Eroica:
Thank you for the reply to my original question. I'm going to have to spend some time with this and study it. I'm at work right now and it is difficult to think about this with 1000 people bugging. When I get home I have a seven month old who needs me. So maybe after I get her to sleep I can have some time with this. Thanks again.

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Originally Posted by Sam5
In the Hafele Keating flying clocks experiment, all the clocks’ averaged time change showed an overall speed up, not an overall slowdown.
The Hafele-Keating experiment was a measurement primarily of the gravitational redshift effect, not time dilation. Those explanations typically ignore gravitational effects - the example given by Eroica specifically points out that it's in "deep space" which is synonymous with "no gravity to worry about."

Moving clocks run slow. So do clocks in gravitational fields. Both effects are present in clocks in orbit, such as in GPS satellites, though we see the sign as opposite for the gravitational effect, since the clock is in a weaker gravitational field compared to the surface of the earth.

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I saw this as a kid in grade school on a Bell science film.

Imagine Tom is in a spaceship, with mirrors on opposing walls and a light pulse bouncing back and forth between them. Tom sees the light pulse moving (of course) at c, it takes w/c = T1 seconds to make one complete circuit of the room, where w is twice the width of the room.

Now, from Harry's point of view, Tom is speeding past at a considerable rate of speed (umm, Harry thinks that Tom's velocity vector is pointing "up"--Tom's head is pointing towards where Tom is going, and his feet are pointing where he's been), and the path of the light pulse is a zig-zag; during one complete cycle the light pulse moves along the hypotenuse of a triangle w on the base and v*T2 on the side, where it takes T2 seconds for Harry to see the pulse of light make a complete circuit. Throwing a bit of algebra at the problem, we see that (cT2)**2 = (vT2)**2+w**2, or w = T2*sqrt(c**2-v**2). Substituting w = cT1, we get T1 = T2 * sqrt(1-(v/c)**2), which might look familiar.

There's a bit of sleight of hand going on in this substitution--Harry could presumably have seen w change (some sort of width contraction); you could set up a different thought experiment to show that this is unlikely.

You can put mirrors on the ceiling and floor of Tom's spaceship and repeat the experiment; if you do so, you'll find that the time dilation from the first experiment isn't sufficient--Tom's spaceship will appear foreshortened with respect to Harry (length contraction).

Something else that falls out from the mirrored ceiling experiment is that simultaneity isn't conserved. Imagine two light pulses bouncing between the ceiling and floor of Tom's space ship--say a red one and a blue one. The pulses are arranged so that they are bouncing out of phase--Tom (on the floor for now) sees the same time between the red pulse and the blue pulse as between the blue pulse and the red pulse. So, Tom thinks that at the same time the red pulse is bouncing off the floor mirror the blue pulse is bouncing off the ceiling mirror, and vice versa. Harry, watching from the outside, disagrees--he thinks that when the red pulse is bouncing off the floor mirror the blue pulse is still heading towards the ceiling mirror.

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Originally Posted by swansont
Moving clocks run slow.
Certain kinds of moving clocks experiencing acceleration run slow. That was known as early as the 16th Century. That’s why early sailors couldn’t determine their longitude while riding with a clock aboard a rocking ship. A special clock had to be designed that counteracted the effect of the constantly changing acceleration aboard a ship.

15. I think you're confusing the mechanical effects of old style mechanical clocks on a boat in choppy waters with relativistic effects. It would take the accuracy of an atomic clock to measure relativistic time dilation, whether special or general, due to the motion of a boat at sea.

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Originally Posted by Glom
I think you're confusing the mechanical effects of old style mechanical clocks on a boat in choppy waters with relativistic effects. It would take the accuracy of an atomic clock to measure relativistic time dilation, whether special or general, due to the motion of a boat at sea.
Glom, my hypothesis is that “relativistic time dilations” in atomic clocks is nothing more than a basic “electrodynamical mechanical effect” felt at the atom that experiences a change from less to more gravitational potential.

With the further hypothesis being that different kinds of clocks slow down at different rates when exposed to more gravitational potential.

And don’t forget that atomic clocks can “speed up” too, when they experience less gravitational potential.

The 1905 term “time dilation” became obsolete in 1911, when Einstein figured out that atomic clocks could both speed up or slow down, when placed under less or more gravitational potential. I don’t know of any clock that just “slows down” but never can “speed up”, due to gravitational potential changes.

And, you can’t successfully use an atomic clock on a ship at sea in choppy waters, for the very same reason the old sailors’ clocks changed rates in choppy waters, because of the constantly changing acceleration. The old sailors’ mechanical clocks ran slow, fast, slow, fast, etc., just as atomic clocks do when experiencing choppy seas and changing accelerations.

17. And, you can’t successfully use an atomic clock on a ship at sea in choppy waters, for the very same reason the old sailors’ clocks changed rates in choppy waters, because of the constantly changing acceleration. The old sailors’ mechanical clocks ran slow, fast, slow, fast, etc., just as atomic clocks do when experiencing choppy seas and changing accelerations.
Eh?

Could you refrence that with something please? Sailors clocks were unreliable instruments because of their acceleration? What if I put a clock in a race car? What happens to my watch on a rollercoaster? Does it speed up and slow down?

18. I believe the problem was that clock were unreliable at that time period. Here is something to look at.

http://www.sailnet.com/sailing/96/f&amp;bapr96.htm
http://www.fordfound.org/news/view_r...ction_index=19
http://www.najaco.com/books/aviation.../longitude.htm

Clocks of that era were totally unreliable and shipboard clocks were wildly inaccurate because of the rolling seas and weather changes that expanded or contracted their parts.
Harrison’s innovation was the creation of a series of clocks that were virtually friction-free, needing only the natural lubrication that a few wood parts provided (which he knew about from his woodworking experience). The parts did not rust and they stayed in perfect balance, no matter how violently a ship tossed or was battered in storms. He combined different materials inside the clockworks in ways that precisely complemented each other. If temperature changes made one expand, the other contracted to exactly counteract the change, keeping the clock’s rate constant.
[My bold]

So, it seems that acceleration wasn't the problem, crappy clocks were the problem. Clock on a ship were subjected to horrible conditions that prevented even the crappy clocks from working well. See, weather rusts metal parts, and choppy seas play havoc with the balance of pendulums (pendulii?).

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Originally Posted by Musashi
Eh?

Could you refrence that with something please? Sailors clocks were unreliable instruments because of their acceleration? What if I put a clock in a race car? What happens to my watch on a rollercoaster? Does it speed up and slow down?

Yes, mechanical and atomic clocks will drift considerably when subjected to constantly changing accelerations, like on board a ship at sea. If you wear a mechanical watch, its rate will change if you go on a rollercoaster or a race car, but only while you are going up and down or sideways.

If you put an electronic watch in your refrigerator freezer, it will lose several seconds over several days. That’s due to the thermodynamic time slowdown factor.

This was a problem of steady speed control on all early portable tape recorders, caused by moving the recorder while it was running, especially when it was rotated, until Sony invented one in the 1960s that had counter-rotating flywheels that tended to cancel out the effects acceleration had on each flywheel.

You can look the think up about the early ship’s clocks on any “clock history” website.

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Originally Posted by Musashi
I believe the problem was that clock were unreliable at that time period.
No, sorry.

Pendulum clocks were very accurate in the old days, but they couldn’t be used on board ships because of the constantly changing acceleration problem. Harrison's chronometers contain devices designed to counter-act the effects of the ship’s constant rocking. It was the rocking of the ship that caused the constant acceleration changes, that made the old type land-based clocks useless at sea.

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Originally Posted by Musashi
So, it seems that acceleration wasn't the problem,
Originally Posted by Harrison clock
John Harrison was a carpenter from Yorkshire. Already at the age of 20, he built a clock with a pendulum made of two metals that could compensate each other's temperature expansion. When he heard of the prize offered by the Board of Longitude, he spent several years developing his first chronometer (later named H1). It had 2 symmetrically connected pendulums that could compensate for each other's acceleration caused by the movement of the ship.
www.kellnielsen.dk/bol.htm+Harrison+chronometer+acceleration&amp;hl=e n&amp;ie=UTF-8]SOURCE OF QUOTE[/url]

22. I think you are intentionally missing the point...

You:
Pendulum clocks were very accurate in the old days

The problem at the time was that there was no accurate way of determining the time at two different places at once. Pendulum clocks had already been invented and used, but on the deck of a rolling ship, such clocks would slow down, or speed up, or stop running altogether. Warm and cold temperatures thinned or thickened a clock's lubricating oil and made its metal parts expand or contract, thus slowing or speeding up tremendously. A rise or fall in barometric pressure, as well as variations in Earth's gravity from one latitude to another, caused a clock to gain or lose time. These watches typically gained or lost as many as fifteen minutes a day. Since one degree of longitude equals four minutes of time, fifteen minutes a day would equal to almost four degrees of longitude. Near the equator, that would translate to almost two hundred and seventy-two miles. In only one day of navigation, the ship would be two hundred and seventy-two miles off course! Imagine a trip across the Atlantic of many months.
Maybe this is hard for you to understand. Have you ever seen a pendulum clock? The changing of the inclination of the deck, away from horizontal, would cause a pendulum clock to lose or gain time. It has nothing to do with the aceleration of the ship. The acceleration of the two intenal mechanism inside Harrison's clock were there to keep the mechanism moving properly on a pitching deck. Sam, you have got to be pulling my leg...

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## Light

Guys:
This has gone way past the point that I hoped it would. With that I have a new question. According to relativity energy and matter are one in the same, right? As matter approaches the speed of light it becomes energy. This is true because we can now bake the earth because of it. If your moving through empty space with no reference point and you are accelerating towards the speed of light will you become energy? After all, there is nothing to refer your speed to. And, light is always moving away from you at a constant speed, so you can never get going that fast anyways, right? Or is it that you have to keep adding energy, hence more mass?

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Originally Posted by Musashi
Maybe this is hard for you to understand. Have you ever seen a pendulum clock? The changing of the inclination of the deck, away from horizontal, would cause a pendulum clock to lose or gain time. It has nothing to do with the aceleration of the ship. The acceleration of the two intenal mechanism inside Harrison's clock were there to keep the mechanism moving properly on a pitching deck. Sam, you have got to be pulling my leg...
Read the quote from the website I gave you. It is acceleration caused by the pitching ship that causes the inaccuracies in the clocks.

A “pitching deck” causes “acceleration” to the people and clocks on board. That’s why passengers get slammed into the walls of a rocking ship. That’s why your coffee cup goes flying off the dashboard of your car when you make a sudden turn.

You need to look up the scientific definition of “acceleration”. It doesn’t only mean “blasting off in a rocket”. It means a change in velocity. And you need to look up the definition of velocity. The rocking ship causes the acceleration of the frame of the clock that is resting on the deck or on a desk in the ship. When the frame suddenly jolts, it is experiencing sudden acceleration, and that messes up the timing of the pendulum swing, and it can also mess up the steady motion of a balance clock flywheel.

25. So, if I tip my grandfather clock (which uses a pendulum) at a 45% angle, it will run ok? I mean, it should right? Since I am not accelerating it once it is moved.

26. ## Re: Light

Originally Posted by Russell
According to relativity energy and matter are one in the same, right?
Wrong. Energy and mass are the same. Matter is "stuff," like atoms and molecules.

As matter approaches the speed of light it becomes energy.
Not quite. As matter (a spaceship, say) approaches the speed of light relative to a given frame of reference, its kinetic energy relative to that frame increases indefinitely. It's still matter, and its rest-mass (ie the mass or energy it has when it is not moving relative to the frame of reference) is unchanged.

If you're moving through empty space with no reference point and you are accelerating towards the speed of light will you become energy?
You must remember that mass/energy is relative. While you may be accelerating close to the speed of light relative to someone else's frame of reference, you are at rest relative to your own frame of reference. So you will observe no change in your own situation. To an outside observer, your kinetic energy is increasing to enormous levels, but you're still a man travelling in a spaceship, made of the same atoms and molecules as before.

And light is always moving away from you at a constant speed, so you can never get going that fast anyways, right?
Correct. Whatever is accelerating you is giving you the extra energy to go faster and faster. But because this energy is increasing your inertial mass (which is a measure of your reluctance to be accelerated), it's becoming increasingly difficult to accelerate you any more. You get closer and closer to the speed of light, but you will never reach it.

In all of this, it's important to remember that there is no such thing as absolute energy. The energy you have depends on the frame of reference relative to which you are doing the measuring. While you may be travelling close to the speed of light relative to one frame - and therefore have an enormous amount of kinetic energy relative to that frame - you might be at rest relative to another frame, and have no kinetic energy!

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Originally Posted by Sam5
Read the quote from the website I gave you. It is acceleration caused by the pitching ship that causes the inaccuracies in the clocks.

A “pitching deck” causes “acceleration” to the people and clocks on board. That’s why passengers get slammed into the walls of a rocking ship. That’s why your coffee cup goes flying off the dashboard of your car when you make a sudden turn.

You need to look up the scientific definition of “acceleration”. It doesn’t only mean “blasting off in a rocket”. It means a change in velocity. And you need to look up the definition of velocity. The rocking ship causes the acceleration of the frame of the clock that is resting on the deck or on a desk in the ship. When the frame suddenly jolts, it is experiencing sudden acceleration, and that messes up the timing of the pendulum swing, and it can also mess up the steady motion of a balance clock flywheel.
You need to differentiate from specific mechanical effects from general physics affects. All clocks will be uniformly affected by their position in a gravitational field. All clocks will be uniformly affected by their speed relative to an observer. These are both relativistic effects (i.e. physics). Some clocks will respond differently than others to being jostled - that is a mechanical/design effect. Mechanical effects can be eliminated with proper design. Physics effects cannot.

There are atomic clocks on ships and boats, and they work quite well, thank you.

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Eroica. An excellently explained example of SR time/length dilation in your tom/dick/harry post! =D>

And a bit of a warning for those of you who haven't been following Sam5's SR arguments in the other posts here. His rationale on many issues border on troll-like. Enter at your own risk!

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Originally Posted by swansont
You need to differentiate from specific mechanical effects from general physics affects.
The only difference between “specific mechanical effects” and “general physics effects” is that within atoms, inside the atoms, the “specific mechanical effects” are called “electrodynamical effects” because they involve not only the gravitational field, but the electric and magnetic fields as well.

Outside the atoms, the overall effects of the acceleration of a pendulum clock’s collection of atoms that we call the “weight”, which the old-timers called the “bob” or the “plumb bob”, we tend to think of that as a simple “mechanical effect”. But inside the atoms, when the same acceleration is felt by all the individual atoms, and their internal harmonic oscillation rate slows down, that is considered to be an “electrodynamical effect”. But it is also a “mechanical” effect on the small internal atomic level.

On that small atomic level there are other “fields” at work inside the atoms, fields other than the basic gravitational field that causes the bob of the pendulum clock to swing. These other fields are the electric and the magnetic fields. This is probably why we think of the internal “mechanical” workings of atoms in “electrodynamical”, rather than “mechanical”, terms.

Originally Posted by swansont
All clocks will be uniformly affected by their speed relative to an observer.
No, this is incorrect and you need to get it out of your mind. “Relative motion” and "observers" never cause any clock to “slow down” or change rates in any way, since the various clocks “don’t know” the other clocks or "observers" are moving relative to them. What you said is a myth that grew out of the fundamental errors of the Kinematical part of the SR theory, which Einstein changed as he developed the General Relativity theory. What is often mistaken for a “relative motion” effect is actually an electrodynamical effect cause by atoms moving through fields.

All clock rate changes are “relativistic” effects, even the change noticed in the 16th Century when pendulum clocks were moved to higher altitudes. Einstein didn’t invent the basic concept of “relativity”. He applied previously known relativistic concepts to the inner workings of atoms. His best work was in taking 16th-19th Century large-scale mechanical effects and inquiring as to what kind of small-scale mechanical effects are at work inside atoms.

Most of his best earliest papers are about atoms and how they work. He had already published many papers about atoms before he ever published the SR paper in 1905, but this is generally not known by most people today.

Originally Posted by swansont
There are atomic clocks on ships and boats, and they work quite well, thank you.
Show me some websites that say there are atomic clocks on ships and boats. I couldn’t find any. All I could find is that commercial ships and boats use the GPS time-code signals for their “atomic clocks”. But they don’t actually take atomic clocks on board the ships and boats.

There are some types of commercial clocks today that are called “atomic clocks” but they really aren’t atomic clocks. They are regular clocks that contain a radio receiver that receives a time coded transmission from Boulder Colorado that is linked to a stationary atomic clock in Boulder, these cheaper clocks are re-set at least once a day by the time code transmissions out of Boulder. You can buy these kinds of “atomic clocks” at Wal-Mart for \$14.95.

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Originally Posted by Sam5
Originally Posted by swansont
You need to differentiate from specific mechanical effects from general physics affects.
The only difference between “specific mechanical effects” and “general physics effects” is that within atoms, inside the atoms, the “specific mechanical effects” are called “electrodynamical effects” because they involve not only the gravitational field, but the electric and magnetic fields as well.
This would imply that if one type of clock didn't work at sea, then no clocks would work at sea, which is false.

Originally Posted by Sam5
Originally Posted by swansont
There are atomic clocks on ships and boats, and they work quite well, thank you.
Show me some websites that say there are atomic clocks on ships and boats. I couldn’t find any. All I could find is that commercial ships and boats use the GPS time-code signals for their “atomic clocks”. But they don’t actually take atomic clocks on board the ships and boats.
I wasn't referring to commercial or private ships and boats. Just because you can't find it on the internet doean't make it untrue.

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