Re: That Minkowski time intervals cannot be current in both frames.


"Jonah Thomas" <jethomas5@xxxxxxxxx> wrote in message
news:20090827144554.0c7058dd.jethomas5@xxxxxxxxxxxx
"Androcles" <Headmaster@xxxxxxxxxxxxxxxxxx> wrote:
"Jonah Thomas" <jethomas5@xxxxxxxxx> wrote in message
"Androcles" <Headmaster@xxxxxxxxxxxxxxxxxx> wrote:
"Jonah Thomas" <jethomas5@xxxxxxxxx> wrote in message
"Androcles" <Headmaster@xxxxxxxxxxxxxxxxxx> wrote:
"Jonah Thomas" <jethomas5@xxxxxxxxx> wrote in message
"Androcles" <Headmaster@xxxxxxxxxxxxxxxxxx> wrote:
"Jonah Thomas" <jethomas5@xxxxxxxxx> wrote in message
I think of a wave as anything periodic.

Lines on screens or paper are not periodic.

If you look from left to right, yours are.

Ok, my desk is periodic because I looked at it from left to right.
The road outside my window is periodic because I looked at it from
left to right.


If it's periodic in time or
space or any other dimension, then it can be described as the
sum> >of> > some number of sine waves.

Chasing Fourier? You need to learn the basics first. Let's go
with> >> "a wave is anything periodic". The Moon orbiting the Earth
is> >> periodic. The Moon is a wave?

Its motion can be described as a wave.

So can any periodic motion, including photons, but that doesn't
mean they ARE waves.

What does it take for it to BE a wave? I figure if the math fits,
use it.

You have to look at it from left to right, apparently.

J: It's my turn. I get to ask what it takes for you to think it's a wave.
==================================================

A: Ok, but you'll have to help me out and tell me what 'it' is.



What is a wave to you?

Sound, water crashing on the shore, riding on a rollercoaster,
periodic movement.
Here's some waves:
http://www.androcles01.pwp.blueyonder.co.uk/Wave/waves.htm
The oscillating piston of the steam locomotive is periodic.

I agree with all of those.

The cycloid is a frozen wave in space, the sinusoid is a
frozen> >> >wave> in time.
If you travel in time with the cycloid by sitting on this:



http://media-2.web.britannica.com/eb-media/88/6488-004-96D89FFF.jp
g> >>> >you'll see an up and down motion like the mass on a spring.>
Sure.

http://www.androcles01.pwp.blueyonder.co.uk/Wave/ripple.gif
That's a model of a real wave.

OK.


http://www.androcles01.pwp.blueyonder.co.uk/Wave/Relative.gif> >> >>
That's a mathematical model of a real wave, AND a spacetime> >> >>
model of a red person or point. That's you, moving with the> >wave.>
Note that the lower wavy line doesn't travel across the> >screen.>
It is a sketch of the travelling wave above, but it's>
"wavelength"> >> is twice the real wavelength. You didn't measure
it> >correctly,> >> because you can't be in two places at once. You
do> >not live in> >> spacetime.

Now... THINK before you answer... what is the frequency of
the> >> >> travelling wave?

The procedure is to pick an axis where the function is
periodic,> >and> > watch the value rise and fall along that axis, and
the number> >of> > cycles per unit is the frequency.

This is a moving graph, and so we can measure the frequency
along> >> > the x axis at one time, or along the t axis at one
x-value, or> >some> > combination. Since it is periodic along both
dimensions I> >think the> > combination would be best, but I don't
know how to do> >that by eye.> >
it's something like:

(at,bx,sine(ax+bt),0)

I haven't thought about it carefully enough yet, but it looks
like> > the wavelength along the ax+bt axis would be something
like> >> > 2pi(ax+bt). I'm not clear what to count as frequency,

Ok, let's pause there, that's what I wanted to clarify. Unless
you> >> separate the t-axis from the x-axis in your mind you'll
remain> >> unclear.

No, when it changes along both you'll get a misleading picture if
you describe it only along one.

No, you are not clear what to count as frequency.
No, unless you separate the t-axis from the x-axis in your mind
you'll> remain
unclear.
No.
No.
No. :-)

There are lots of circumstances where it's appropriate to make your
axis be a linear combination of fundamental axes. Why isn't this one
of them?

Frequency is DEFINED as follows.
http://www.merriam-webster.com/dictionary/frequency
1 : the fact or condition of occurring frequently
2 a : the number of times that a periodic function repeats the same
sequence of values during a unit variation of the independent variable
b : the number, proportion, or percentage of items in a particular
category in a set of data
3 : the number of repetitions of a periodic process in a unit of time:
as a : the number of complete alternations per second of an
alternating current b : the number of complete oscillations per second
of energy (as sound or electromagnetic radiation) in the form of waves

J: I'll take #2a.
==================================================
A: Ok, what's the frequency of 1/7 = 0.142857142857142857142857142857...?


Nowhere does it say the number of complete wiggles per mile.

J: When "miles" is the unit of "the independent variable" it does.

The number of wiggles per inch depends on the length of each wiggle,
the number of wiggles per second depends on the duration of each
wiggle. Inches per second is speed, if you confuse wiggles per inch
with wiggles per second then speed will be unclear and you will not be
clear what to count as frequency.

J: You have to be clear what your units are, agreed.

Frequency is how often a repetition occurs, but if you travel
with> >the> travelling wave then you change the *place* where the
repetition> >> occurs.

Yes, exactly.
No.
No, exactly.
No. :-)

http://www.androcles01.pwp.blueyonder.co.uk/AC/doppler.gif
The magenta ball "sees" no repetition.
The gold ball "sees" a doubling of the transmitter frequency.
The only frequency that remains constant and makes any sense is
the transmission frequency. Ok, the red/blue antennae see the
same> >> frequency as the transmitter, but only because they don't
move> >> relative to the transmitter.

Yes, but your wave is moving in space and time both, and you want
to> > measure the movement in time only.

The wheel that produces the cycloid is moving in space and time
both.> The cycloid doesn't move at all, not in space and not in time.
A boat on water moves up and down as the wave passes beneath it.

You can describe the cycloid with a movement in space. Look at its
graph from left to right. Agreed on the boat.

You can move back and forth in space, overlaying one wiggle with
another, you can't do that in time. No amount of looking from left to
right can tell you how many wiggles were drawn backwards, but on the
time axis only forward wiggles are allowed and none can be overlaid.
http://www.drillspot.com/pimages/8/841_300.jpg
This is called a chart recorder.
http://www.drillspot.com/pimages/8/841_300.jpg
The pen wiggles in space and the paper goes forward in time.
Running the paper backwards does reverse time, it fucks up the chart.
Do not confuse the time axis with the x-axis and read the chart
recorder top to bottom.

J: Sure, don't make the axis wiggle back and forth unless you have a good
reason why that is appropriate for your particular problem.

Now here's a quirky thing. If the speed of the travelling wave
is given by c = wavelength * frequency, and you measure
the frequency at the orange ball, then you get
speed = (wavelength/2) * (frequency *2) and the speed doesn't
change. That's obviously nonsense.

Let's call it frequency*2, never mind if the picture gets out of
phase. Now how do you get wavelength/2?

That's a good question.
"The speed is always c, not counting dielectric effects. The
wavelength
is short while you're approaching, and it lengthens as you leave."
--> Jonah
Thomas.
How did you get a speed of c?

It's inconvenient to have the speed of light vary.

Well, tough ***. Nature doesn't care about your convenience.

J: Agreed. So if it turns out that the speed of light varies when you
measure it, then you just have to put up with that. And if it turns out
that the speed of light doesn't vary when you measure it, you have to
put up with that too. Do you know which is the reality?
================================================
A: Being a scientist, I begin with the observation of the reality,
investigate
it and and then develop the theory.
Do you know which is the theory?





The way people have
dealt with that inconvenience left them with lots of other
inconveniences, things which a lot of physics students take a long
time to learn to deal with. I'm learning how the system works and
looking for a better way at the same time.

You'd better learn it works first and find a better way second.
It's inconvenient if pencils bend in water.
http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/optpic/brokpen.jpg
It's much more convenient if the light bends.
How long it takes you to deal with that depends on your intelligence.

Are you saying you have a way that works, that depends on the relativity
effects all being something that happens to light? How does it work?
Does it work?

==================================================
No.



If there was a clear reason to have a preferred absolute rest frame,
then I'd gladly accept the inconvenience of using it. The claim that
all physical laws work the same at all velocities would be wrong,
and we'd all just have to get used to that. It would be a new and
exciting time. But that has not happened. Physicists prefer to
believe that no velocity is better than any other velocity, or even
different in any fundamental way. As a consequence they get lots of
results that are counterintuitive, and nobody goes into physics
unless they can believe these counterintuitive ideas. After they
accept these, they have no resistance to accepting other
counterintuitive ideas. We wind up having only physicists who don't
care whether physics makes any sense. They do get some results this
way. I think we might get better results if we carefully looked for
ways to make sense -- we can't demand that the world fit our
preconceptions but we should get clear conceptions that fit the
world. That won't happen while it is not a priority for physics. So
anyway, here we are. People accept that if you measure the speed of
light it will give the same result no matter what your speed is.

Those are called "fools".

You can
accept that or reject it. If you accept it, that doesn't make a
virtual pin crossing a 2D picture of a 3D wave have the same speed
no matter what, nor does it make the speed of the picture of the
wave have the same speed.

Very good. Let's move on and reject it, or we'll be forever
philosophizing about fools and people instead of getting on with
understanding the real world.

J: When the speed of light gets measured is it always the same?

A: No, it isn't.

J: If so, do
you have an explanation that works better than SR?

A: In hypothetical sentences introduced by 'if' and referring to
past time, where conditions are to be deemed 'unfulfilled',
the verb will regularly be found in the pluperfect subjunctive,
in both protasis and apodosis.
-- Donet, "Principles of Elementary Latin Syntax"

J: If not, do you have
an explanation why practically everybody believes it's so?

A: They are fools, sheep, bigots, they believe whatever they are
told to believe. Let's move on and reject it, or we'll be forever
philosophizing about fools and people instead of getting on with
understanding the real world.
If you want to study people I'm not the right person to help you.

http://www.merriam-webster.com/dictionary/bigot
: a person obstinately or intolerantly devoted to his or her own opinions
and prejudices;

This newsgroup is about the mathematics of relative motion,
a subject in which you are weak.

For some strange reason the cretin Einstein wanted to single out light
as the only phenomenon that disobeys relativity, by stage magic.
You, being a fool in his audience, do not look at how his magic
trick is done, instead you listen to those around you and nod your
stupid head in agreement with them.
I, as a scientist, am trying to tell you how you are fooled and you
want an explanation why practically everybody believes it's so.
I really don't give a flying *** about practically everybody else,
I'm discussing physics, so no, I do not have an explanation for
idiocy beyond the simple herd instinct, the inclination to be like
others and follow the leader. Why should I?




It looks to me like newspeed = frequency*2 * wavelength =
speed*2.> > Which is what it ought to be.

Very good. But the frequency it leaves the transmitter doesn't
change> (and is the same at all the red balls) and two crests pass
the orange> ball in the same TIME it takes one crest to pass a red
ball, c is the> same for all so the wavelength must be halved. Which
is what it ought> to be because it is blueshifted.

EVERYBODY KNOWS (haha) "The wavelength is short while you're
approaching, and it lengthens as you leave." -- Jonah Thomas.
EVERYBODY KNOWS (haha) "that light is always propagated in empty
space with a definite velocity c which is independent of the state
of> motion of the emitting body." -- Albert Einstein.
After all, if Einstein said it, it MUST be true. He's god, He who
must be believed.
I'm just a dumb crank that refuses to believe a word the arsehole
said.

Well, maybe you can find a better way. If the complaints people had
about galilean relativity were valid, you'd need something better
than galilean relativity. If the complaints they had about classical
physics were valid, you'd need something better than classical
physics.

Were those complaints valid, or were there mistakes in them? Note
that the complaints could be valid without validating their
solution.

Here's a nice complaint.
http://en.wikipedia.org/wiki/Emission_theory
The simplest form of emission theory says that radiating objects throw
off light with a speed of "c" relative to their own state of motion,
and (unless we have reason to believe that the light changes speed in
flight), we then expect light to be moving towards us with a speed
that is offset by the speed of the distant emitter (c ± v) ).

J: OK, I'll try that out.

1.. If a radiant star moves across our field of vision, light given
off by
differently-moving atoms in its atmosphere should take different
amounts of time to reach us. Since the retreating atoms would have a
"red" Doppler shift, and the approaching ones a "blue" Doppler shift,
the passing star might be expected to appear as a "rainbow streak".

J: My understanding is that this is the reason that the bright lines on
emission spectra are thick bright lines and not razor-sharp thin lines.
How much difference in speed would it take in the star to get the effect
you're looking for?
================================================
A: Your understanding is wrong.
http://www.ktgss.edu.hk/Academic/physics/phyindex/image/solarspectrum.jpg




Is it valid? The star is moving ACROSS our field of vision, which
cannot then be toward us or away, and is supposed to produce a
doppler- shift rainbow streak. No quantification given.

J: What would it take to quantify that?

A: Model it, mathematically. Then you are "doing science".


I have a coin, but it has worn down after being in circulation. It
therefore contains less metal than it should and I can't spend it,
it doesn't have full value.
Of course that is nonsense, as is any argument without quantification.
Here's the rainbow streak of the radiant star.
http://www.androcles01.pwp.blueyonder.co.uk/Orbit/Orbit.htm

J: I learned from electron microscopy that if you're willing to look for
rare things, you can find any image you want that way. It's surely true
for astronomy too. How common is the effect you show here?

A: As common as the Hubble Space Telescope has been pointed at
red giants and the light filtered to give only the ultraviolet light.
http://hubblesite.org/newscenter/archive/releases/1997/26





but if |ax+bt| is the unit of
distance on that axis, then the frequency ought to be 1/2pi
per> >> > unit.

Or if the unit is (ax+bt)/|ax+bt| then the frequency might be
1/(2pi|ax+bt|)

Was that right?

You can't mix the x-axis and the t-axis.

If the motion is along both of them, how do you separate them?

You draw a cycloid for one and a sinusoid for the other.
You don't need a time axis for a cycloid, you can rotate the wheel
backwards and forwards and still hit the cycloid curve. It's
a little harder with the piston of a steam engine.
http://www.androcles01.pwp.blueyonder.co.uk/Tornado.gif
That's why a draw animations. They take care of the time axis.
You can't go back in time, but you can go back in space.
Time is not a vector.
http://www.androcles01.pwp.blueyonder.co.uk/Vector/Vector.htm

For purposes of analysis you can go back and recalculate from any
time or place you want. If it isn't too late to collect data you can
check your estimates. I prefer physics where the future doesn't
reach back and communicate with the past. If you create a photon
that doesn't interact with anything at all until it touches an atom
in a star 1000 light years from here, I don't want the atom 1000
years from now to reach back and tell the photon's source what
happened. If that turns out to be a particularly good way to
describe what happens then I'll accept it, but I'll have to look it
over carefully first.

Well, you could choose one for an independent variable if the
other> > is a dependent variable. But depending, it might make more
sense to> > have both of them as dependent variables and have the
independent> > variable be a rotation term.

Makes more sense if you learn that mathematics is a shorthand
language> to be used by those that understand it.

Sure. And you can use it wherever it fits.

And you can tell lies with it or write nonsense with it.

Yes. A language that was so restricted that it doesn't let you tell a
lie would be very hard to say much in.

1/2 [ tau(0,0,0,t) + tau(0,0,0,t+x'/(c+v)+x'/(c-v))] =
tau(x',0,0, t+ x'/(c-v))

That says:
the speed of light from A to B is c-v,
the speed of light from B to A is c+v,
the "time" each way is the same.

Not being versed in mathematics, you can't read it, can you?

Do you have an explanation why practically everybody believes it's so?
Only that's where your beloved "Lorentz Transformations" come from,
which practically everybody believes.



It's very easy to write F =dp/dt, or at a freshman level F= ma,
but Newton said

LAW II.
The alteration of motion is ever proportional to the motive force
impressed; and is made in the direction of the right line in which
that force is impressed.

If any force generates a motion, a double force will generate
double> the motion, a triple force triple the motion, whether that
force be> impressed altogether and at once, or gradually and
successively. And> this motion(being always directed the same way
with the generating> force), if the body moved before, is added to or
subtracted from the> former motion, according as they directly
conspire with or are> directly contrary to each other; or obliquely
joined, when they are> oblique, so as to produce a new motion
compounded from the> determination of both.


It means the same. F = dp/dt is merely shorthand.
You have to know that p=ma, that p is momentum, that Newton called
it> "motion".

When you read mathematics, read it as the shorthand it is. That
means> take your time, there is a lot more in it than you realise. I
hope> I've shown you that.

I'm slow picking up math that describes physics. I'm not trying to
be slow, it just works out that way.

You and many others. Many haven't learnt to read algebra beyond
the "See Spot Run" level. Trying to make sense of the Declaration
of Independence won't happen without a better vocabulary.
The language of physics is mathematics.

Doppler says
c-v
f' = f -----------
c

That's "See Spot Run" level for light.

Doppler says
c
f' = f ----------------
c-u

That's "See Spot Run" level for sound.

Doppler REALLY says

c-v
f' = f -----------
c-u

where v and u are speeds relative to the AIR.

Look at it this way:
Here's the rifled barrel of a spud gun.
http://www.spudtech.com/images/products/sch80rifled.jpg
The spud pellet will spin in flight.
If I increase the air pressure in the gun
1) the pellet will travel faster.
2) the pellet will spin faster.
3) it will have a longer "wavelength".
The "wavelength" is one full turn of the spud pellet in the
barrel> >> of the gun.
The barrel shown isn't long enough for a full wavelength, it
only> >> has 2/3 of a turn, but obviously I could change that ratio
with different machining. What this means is two spud pellets
can travel at the same speed but with different spin rates.
It also means that I can change the speed of one and not the
other> >> by changing the pressure, and I can run toward the target
which will change the speed at which the pellet hits the target
without changing the muzzle speed.
The time axis is INDEPENDENT of the x-axis.

So with two independent variables you don't have an equation in
one> > variable unless you can set the other one.

Yes.

Match the caption to the gif:

A) http://tinyurl.com/lv2fl7
B) http://tinyurl.com/njgouh
C) http://tinyurl.com/klkfc9
D) http://tinyurl.com/l6lt4g
1) applies to light (in vacuum) and sound (in air)
2) applies to light but not sound
3) applies to sound but not light
4) applies to neither light nor sound

A1
Correct.

B4
Incorrect.

C3 -- traveling at the speed of sound

Correct.

D4 -- Maybe in a hurricane where the wind is Mach 1?
Correct.

B2 is merely A1 with the principle of relativity applied.
From the starship Enterprise's point of view, the star
is approaching the ship. It cannot change the speed of
the light it approaches.

It looks to me like the star is changing the speed of the light as
it approaches. Not just the light it emits now, but all the light it
has already emitted gets redrawn as if it had started out in the new
location.

A) is the rest frame of the star.
The star is not moving, but it is emitting light at c.
The ship is approaching the star at c, so the light
is received by the ship at 2c.

B) is the rest frame of the ship.
The ship is not moving, but it is receiving light at 2c.
The star is approaching the ship at c, so the light
is received by the ship at 2c.

J: You have this working? No paradoxes or puzzles?

A: Which ship is moving?
http://www.androcles01.pwp.blueyonder.co.uk/Doppler/ship2sloop.gif
http://www.androcles01.pwp.blueyonder.co.uk/Doppler/sloop2ship.gif

Most people understand that if two ships are far from land, it is impossible
to tell which is moving simply by observing one from the other.

When I create a gif, I copy and paste. You can see the
same flaws in both A and B, little red dots in the star and a
blue streak in the tail of the ship, that I missed when creating
the images.
Do you think there is a paradox in the Principle of Relativity?
All paradoxes were created by Einstein when he singled out light
as the one phenomenon that disobeys the PoR.

Do you have an explanation why practically every fuckin' idiot
and his dog believes it's so?



As for D4, you are correct, there is no way approaching a star
will cause the light it emits to slow down.
BUT...
"It follows from these results that to an observer approaching a
source of light with the velocity c, this source of light must
appear> of infinite intensity." -- Albert Einstein.
The star is a source of light. The observer is the starship.
The compressed pattern is that of C3, a sonic boom, you were
correct on that. But there is no equivalent lumic boom without
aether. And the aether went away with Michelson-Morley.
So you've disagreed with Einstein. Never mind, he was an idiot
and you are smarter than you realised.
You scored 75%.

Problem:
A train has a whistle, which emits a 400 Hz sound. You are
stationary
and you hear the whistle, but the pitch is 440 Hz. How fast is
train> moving towards or away from you? Solution:
The pitch is higher, so the train is moving towards
you.> Its speed relative to you is found from f =
f0v/(v-vs).> We have(v-vs) = f0v/f = (400/s)(340
m/s)/(440/s) = 309m/s.> Therefore vs = 340m/s-309m/s =
31m/s = 69mph.>
If both source and observer are in motion, then the apparent
frequency> of the sound wave reaching the observer is

f = f0(v + vo)/(v - vs)

If observer is in motion and the train stationary, then the
apparent> frequency of
the sound wave reaching the observer is

f = f0(v + vo)/v

http://electron9.phys.utk.edu/phys135d/modules/m10/doppler.htm

Yes?

A train has a whistle, which emits a 400 Hz sound. You are
moving and you hear the whistle, but the pitch is 440 Hz.

What is YOUR speed? (assume the train is standing still)

J: Without getting an independent source for your formula, which fits my
prejudices and my memory of that formula the last time I looked it up:

f=f0(v+v0)/v

440 1/s = 400 1/s (v-x)/340 m/s because you go toward the sound.
1.1 = (v-x)/340 m/s
374 m/s = (340-x) m/s
-34 m/s = x

A: How do you reconcile that with
http://electron9.phys.utk.edu/phys135d/modules/m10/doppler.htm
with it's worked example of 31m/s ?

Train is moving at 31 m/s, you are stationary,
you hear 440 Hz from it's 400 Hz whistle.
You are moving at -34 m/s, train is stationary,
you hear 440 Hz from it's 400 Hz whistle.

http://www.androcles01.pwp.blueyonder.co.uk/1st/Postulates.htm






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