Franz Heymann wrote:





even though the
experiments to determine epsilon_0 and mu_0 have nothing to do with


light.

No experiments have ever been done to determine the values of eps0 and
mu0.
They are artefacts necessary to define a certain set of units.
Such experiments are logically impossible, for the following reasons:

mu0 is *defined* to be precisely 4* pi*10^-7
and eps0 is *defined* to make eps0*mu0 = c^-2
(and c, in turn, has a *defined* value, but we'll let that pass)





See my other post, eps0 is no less fundamental than G. *Today* we don't
need to define them as separate fundamental constants, since we know
that eps0 = (mu0*c^2)^-1 and vice versa, but if you know the history of
electromagnetism you'll know that they could not have been defined this
way before Maxwell proved that the full set of Maxwell's equations
implied that electromagnetic waves should always travel at velocity
1/squareroot(eps0*mu0), and realized that this value was very close to
the measured value of the speed of light, implying that light was really
an electromagnetic wave, something that no one had realized before him.
Back then they were defined experimentally--for example, to derive
Gauss' law you would have to find the correct value of the constant to
give the correct relation between charge and electric flux in whatever
system of units you were using (see
http://hyperphysics.phy-astr.gsu.edu...maxeq2.html#c1 )
Again, this is exactly analogous to the constant G, which relates the
the gravitational force between two masses to mass1*mass2/distance^2 in
whatever units you're using. And you could choose a system of units
where you *define* your mass units so that G would take a certain value,
but this wouldn't make it any less fundamental, it would just trasfer
uncertainty in G to uncertainty about your mass units (just like how,
since we now define the meter in terms of the speed of light, that means
we have some uncertainty about the length of a meter). Similarly, if we
use cgs units where 1 esu is defined so that eps0 is 1, that means we
have some uncertainty about the exact value of one esu; on the other
hand, if we use SI units where we define the ampere so that mu0 has a
value of 4pi*10^-7, that introduces some uncertainty into the exact
value of 1 ampere.

Jesse

I wrote:



Well, you're thinking about it wrong. It would be possible to choose
units of mass such that the gravitational constant G was equal to 1,
but that wouldn't make it any less real as a physical
constant--similarly, in cgs units, the basic units of charge (emu)

Sorry, that should be esu...emu is the unit of magnetic charge in cgs units.

Jesse

"Jesse Mazer" wrote in message
...


I wrote:



Well, you're thinking about it wrong. It would be possible to
choose
units of mass such that the gravitational constant G was equal to
1,
but that wouldn't make it any less real as a physical
constant--similarly, in cgs units, the basic units of charge (emu)

Sorry, that should be esu...emu is the unit of magnetic charge in
cgs units.

You might know what you were trying to say both in the original
statement and the correction.
I doubt if anybody else would.
Comment on this garbage, for instance
"emu is the unit of magnetic charge in cgs units"

Franz

"Jesse Mazer" wrote in message
...


Franz Heymann wrote:





even though the
experiments to determine epsilon_0 and mu_0 have nothing to do
with


light.

No experiments have ever been done to determine the values of eps0
and
mu0.
They are artefacts necessary to define a certain set of units.
Such experiments are logically impossible, for the following
reasons:

mu0 is *defined* to be precisely 4* pi*10^-7
and eps0 is *defined* to make eps0*mu0 = c^-2
(and c, in turn, has a *defined* value, but we'll let that pass)





See my other post, eps0 is no less fundamental than G. *Today* we
don't
need to define them as separate fundamental constants, since we know
that eps0 = (mu0*c^2)^-1 and vice versa, but if you know the history
of
electromagnetism you'll know that they could not have been defined
this
way before Maxwell proved that the full set of Maxwell's equations
implied that electromagnetic waves should always travel at velocity
1/squareroot(eps0*mu0),
and realized that this value was very close to
the measured value of the speed of light, implying that light was
really
an electromagnetic wave, something that no one had realized before
him.

That is pure crap, since eps0 and mu0 were invented only in the late
thirties of the previous century, by which time Maxwell was no longer
around to comment on that.

What Maxwell showed was that the speed of EM plane waves in free space
was related to the ratio between the esu of charge and the emu of
charge, a quantity which had already been measured experimentally at
that time.

Back then they were defined experimentally

That is a contradiction in terms.

[snip]

Franz

"Jesse Mazer" wrote in message
...


Androcles wrote:

"Jesse Mazer" wrote in message
...

Androcles wrote:


"Jesse Mazer" wrote in message
...


Creighton Hogg wrote:



On Wed, 12 Jan 2005, Jesse Mazer wrote:




Androcles wrote:




"Jesse Mazer" wrote in message
.. .




Androcles wrote:





"Jesse Mazer" wrote in message
.. .





Androcles wrote:






"Jesse Mazer" wrote in message
...






Androcles wrote:







In a reference frame in which the apparatus is
stationary, x and y don't
change as the apparatus is rotated (assuming x and y are
the
arm-lengths).







Exactly. So you prove nothing. However, Einstein's
postulate is
"light is always propagated in empty space with a definite
velocity
c which is independent of the state of motion of the
emitting body"
Reference :
http://www.fourmilab.ch/etexts/einstein/specrel/www/

The Earth is moving in the empty space, which is the
reference frame.
Are you trying to deliberately obfuscate the problem?







Empty space doesn't have a particular reference frame in
Einstein's theory.






Then light will be source dependent.
Androcles.








Nope, not according to the laws of electromagnetism.





Which one? Gauss, Faraday or Ampere?
Androcles.





The fact that the speed of light is independent of the source
can only be derived using all of Maxwell's laws.




When you can read a graph, we'll discuss it. Until then, it's a
waste of time.
Androcles.




I can read your graphs, but with no descriptions of what is being
measured, I don't know what they mean. For example, on the graph
you posted at
http://www.androc1es.pwp.blueyonder....r/00918-ck.gif
one axis measures time and the other measures "m", which I would
guess is meters--but what is it that is being measured in meters?
Without context, a graph like that is meaningless--if you are
willing to explain the context, I will try to address it.

In the meantime, regardless of what that graph shows, it doesn't
change the fact that you have not addressed the issue that
Maxwell's laws are all based on experiments with electricity and
magnetism that are extremely well-confirmed, and which don't
involve light at all; once you have these laws, you can show
mathematically that together they imply the velocity of
electromagnetic waves is always 1/squareroot(epsilon_0*mu_0), and
that this "coincidentally" happens to match the observed speed of
light very accurately, even though the experiments to determine
epsilon_0 and mu_0 have nothing to do with light.



Not to be a jerk, but epsilon_0 and mu_0 are really an artifact of
using SI units and wouldn't have shown up Back in The Day.




OK, but they did have terms for the permittivity and permeability
of the vacuum back in the day--whatever symbols they would have
used, just put them in place of epsilon_0 and mu_0 in the above
paragraph and the argument is unchanged.

Jesse


So you DO believe in aether, then, because those are the very
properties that
define it.
Androcles.




No they aren't. They are just constants that have to be included in
order to express the relationship between, say, the total charge
enclosed in a volume and the total electric flux passing through the
surface. That's just Gauss' law, which you said earlier you believed
in--see the description he

http://hyperphysics.phy-astr.gsu.edu...maxeq2.html#c1


The magnetic constant m0 = 4p x 10-7 T m/A
is not a property. It is a unit conversion, and total bull****
to claim c = 1/sqrt( a couple of constants) as if they were
properties.


It's not just a unit conversion. As an analogy, think of the
gravitational constant G in Newton's equation F=GMm/r^2, where F is
the gravitational force between two objects of mass M and m a distance
r apart. Newton recognized based on empirical data that the
gravitational force between two objects should be proportional to the
product of their masses divided by the distance between them squared,
and part of the purpose of G is just to get the units to work out, but
it is not just a unit conversion, it's a fundamental physical
constant. If G had a higher value, the force between two given masses
would be stronger, for example. You have to do careful experiments to
determine the correct value of G--for example, see this article titled
"Determination of the gravitational constant G by means of a beam
balance":

http://www.europhysicsnews.com/full/.../article6.html

It's the same with the magnetic constant, it is not just a unit
conversion factor, it has to be determined experimentally. If its
value was different, this would alter the predictions about the
relationship between the amount of electric current flowing through a
closed loop and the strength of the magnetic field created by this
moving current. To determine its value, you have to do experiments to
look at the actual relationship between these constants, just like how
you have to do experiments to find the relationship between the mass
of two objects and their distance vs. the gravitational force between
them.

It is your claim that c is invariant, and use Maxwell's equations
as the basis.
I think you speak with forked tongue, you have not said c is
relative to.


In any reference frame which Maxwell's laws hold, it can be proved
mathematically that electromagnetic waves must travel with a velocity
of 1/squareroot(permittivity*permeability).

Not by you I cannot, but you are welcome to try.

The day you can prove
c = 1/squareroot(permittivity*permeability) = c+v
without assuming
1/2 [AB/(c+v) + BA/(c-v)] = AB/(c+v)

publish it in a mathematical journal (not a scientific journal, they'll
believe
anything).




In Maxwell's day people only thought Maxwell's laws would hold exactly
in a single preferred reference frame (which they imagined to be the
rest frame of the aether), and they'd have to be altered by a Galilean
coordinate transformation in other frames.

In Einstein's day, people
thought Einstein's laws could violate the invariance of distance and
time because he ASSUMED (tau 0+ tau2)/2 = tau 1. Even today,
some people are still gullible enough to believe that can prove what
they assume, aren't you?.


With relativity, physicists now believe that they hold exactly in
*every* frame.

No they don't. Relativists are not physicists.
The are not even scientists, they are blind fools that believe
the journey time from London to New York, 7 hours, added
the journey time from New York to London, 6 hours, when
added (13 hours) and divided by 2, equals 7 hours, because
Einstein said so. In Einstein's day it took two weeks to make the
same journey, the Wright Brothers had flown at Kitty Hawk
two years before, and you are still living in Einstein's day,
not even aware of the jet stream, that being the frame of
reference in which the speed of sound is 731.4 metres/second.
In Einstein's day, Marconi had sent the first radio signal
across the Atlantic just 4 years before Einstein published
his nonsense and you are still living in Einstein's day.
I think you must be at least 118 years old, because I strongly
doubt anyone under the age of 18 would have knowledge
of Maxwell's equations. Either that, or you do not live in the
real world, preferring your world of fanciful make-believe.

You certainly cannot prove mathematically any of the things
you are claiming. In Einstein's day they had padded cells and
straight-jackets for mad people.

[remainder snipped, I don't have anymore time for your nonsense]

Androcles.

"Jesse Mazer" wrote in message
...
I do not have a theory. I have a model, and it is the vector addition
of velocities, too simple to call a theory.
There is nothing in the description above that accounts
for the secondary maxima so commonly observed. At 6000 ly,
there MAY not be enough distance for the faster light to pass the
slower before arriving, it depends on the velocity of the star and
the orbital attitude. I have not seen the curve for T Pix.
Nor can I disprove the above, it is a matter
of plausibility. I don't see the moon sucking up Earth's oceans,
do you? What I do see is the rings of Saturn where a moon once
was, ripped apart by tidal force. Were you aware that the moon
keeps the same face toward the Earth because of tidal force?
How does a less massive star suck matter from the more massive?
It is as plausible as the moon sucking the Earth's oceans dry
from a distance of the GPS constellation.


From the description, it seems to me that it was the central dense
white dwarf which was more massive, and the orbiting star was less
massive, and also that it was in a "close orbit".

Oh, ok. The Earth sucked the water from the lunar seas, the Moon
got tired of being bullied and moved further away.
Got any more good howlers, Dr. Physicist?

I would assume that astrophysicists have actually modelled the gravity
from the white dwarf in such a system to show that it could indeed
suck up material from the orbiting star, I doubt they are just
guessing without doing any calculations.

You'd assume that, would you?
Got to have some sort of theory, right?
There is no water or air on the moon, the Earth must have sucked it all
away.
How do you type messages like that in a straight-jacket?

I'll be honest with you. I don't really care what you assume, believe or
doubt.
Take it back to the funny farm.
Androcles








If your theory can't make accurate predictions that no other theory
can, then you can hardly expect physicists to throw out Maxwell's
laws, which each have a mountain of experimental evidence to support
them, in favor of your theory.


I am not asking for Maxwell's equations to be thrown out, and I do not
have a theory.


Again, it is provable in a purely mathematical sense that if all of
Maxwell's equations are correct in a particular frame, the velocity of
electromagnetic waves *must* always be 1/squareroot(e0*m0) in this
frame. Denying this is like denying that pi is an irrational number.
The only way it's possible to deny that the speed of light is
independent of the source velocity is to deny that Maxwell's laws are
actually correct in any reference frame.

I have a model. Einstein does not have a theory, he has
a wild and stupid guess about the speed of light being independent
of the motion of the source


Einstein didn't guess the speed of light is independent of the motion
of the source, Maxwell had already proved that must be true if
Maxwell's laws are true. What Einstein guessed is that the speed of
light would be *the same* in every reference frame. Do you understand
the difference between these two statements? For example, the velocity
of a sound wave is independent of the velocity of the source (the
sound from a car driving towards me travels at the same speed as the
sound from a car parked in the same location), but it is certainly not
the same velocity in every reference frame.

Are the bullets from the machine gun supposed to be analogous to the
photons from the star orbiting the nova? If it's just the orbiting
star that's responsible for the variation in magnitude, why don't we
see the same degree of variation in magnitude in binary systems where
the main star hasn't gone nova?


Carefully monitor the nearest binary, Sirius, 8 light years away.
Note the exact brightness for 50 years (its period) and you'll see
a change in magnitude over that 50 year period of 0.001 magnitudes.
Yes, I'm guessing the exact figure, but I'm in the right ball park.
Distance, period, attitude. If the system is seen edge on, far enough
away
and short enough period, you have a chance.
Face on, there is no component of velocity in our direction to see.
Too long a period, you'll never see it.
You are not going to wait 50 years.
Too close, you'll never see it.


So are you saying that the variations of magnitude in a recurrent nova
would be about the same as the variations of magnitude in an ordinary
binary star system at the same distance, where the orbiting star is of
about the same size? I'm almost certain this would be completely
wrong, the variations for an recurrent nova would be far greater.





Now, If Maxwell had had a computer and a program like mine,
he would still have agreed with Gauss and Faraday. But he would
not be saying there was any aether. He would have been saying
the speed of light in the vacuum of space is constant with respect
to the source at the time of emission.


No he wouldn't, because he'd know that each of the laws individually
(Gauss' laws for electricity and magnetism, Faraday's law, and
Ampere's law) are well-supported by experiment, and that together
they *must* imply that the speed of electromagnetic waves is
independent of the velocity of the source. To accept each law
individually but deny this conclusion is like accepting that A=B and
B=C and C=D but denying that A=D.

So, which of Maxwell's laws do you want to throw out?


Any that assumes e0 is a property of aether and not just a units
conversion
constant.


There are no laws that require you to assume e0 is property of the
aether (none of the physicists who use Maxwell's laws today believe it
is), but it isn't a unit conversion constant either. As I explained in
my last post, it is a physical constant analogous to the gravitational
constant G.

So, again: which of Maxwell's laws do you want to throw out? If you
keep all of them, it is a proven fact that the velocity of
electromagnetic waves in any frame in which the laws are valid *must*
be equal to 1/squareroot(m0*e0).


There is no known way you can make a slight modification to Maxwell's
laws and get the prediction that electromagnetic waves have a
velocity that's dependent on the source--if you discover such a way,
you should publish it. And again, each one of those laws has a huge
amount of experimental evidence to support it individually.


Ok, Ptolemy.
You carry on believing in aether, and the permittivity of free
space is epsilon0. I call that the permittivity of aether.


Well then, you don't know what the hell you're talking about. Ampere's
law won't work without the constant epsilon0, any more than Newton's
law of gravitation will work without the constant G. They are both
necessary for making correct physical predictions (*and* for getting
the units to work out).


You carry on believing 2AB/(t'A -tA) = c, when A and B are in relative
motion.
You may not like the word "aether" but the cap fits, so wear it.


It doesn't fit. e0 is just an electromagnetic constant, like G is a
gravitational constant. If Newton had believed in a "gravitational
aether" which transmitted the gravitational force, and had named G the
"gravitational aether tensile strength" or something, would that
require anyone who used the equation F=GMm/r^2 to believe in
gravitation aether? Of course not, it's just a constant, the name is
arbitrary. If Newton had certain beliefs about what G "meant", that
wouldn't require us to share those beliefs in order to use his
equation.



Once you have these laws, you can show mathematically that together
they imply the velocity of electromagnetic waves is always
1/squareroot(epsilon_0*mu_0), and that this "coincidentally"
happens to match the observed speed of light very accurately, even
though the experiments to determine epsilon_0 and mu_0 have nothing
to do with light.


You are right. "Coincidently". Actually, contrived.


"Contrived"? How can it be "contrived" when the values for
permittivity and permeability were measured *before* anyone thought
there would be a connection with the speed of light, and using
techniques that have nothing to do with light? Only after both the
values of these constants and all four of Maxwell's equations had
been discovered did Maxwell realize that the laws implied
electromagnetic waves would always travel with a velocity that came
out very close to c. Since both the equations and the values were
already known, there was no way he could have fiddled with them in
order to insure it would work out this way, it was a complete
surprise.



You may not like the word "aether" but the cap fits, so wear it.


You didn't answer my question. Are you avoiding it because you know
there is no way for you to answer without either denying an obvious
truth or admitting I am right?



What is the speed of
sound in a vacuum? What is the volume of a gas at zero degrees
Kelvin?
Just extrapolate, easy enough. Trouble is, there is no sound in a
vacuum.
There are no gases at zero Kelvin. That doesn't matter to you,
though.
You believe the vacuum of space has the identical properties of
aether,
the equations say so


No, I simply believe that all of Maxwell's equations give correct
predictions about the electric and magnetic force in all known
situations involving macroscopic charged objects. Do you disagree?


You may not like the word "aether" but the cap fits, so wear it.



You didn't answer my question. Are you avoiding it because you know
there is no way for you to answer without either denying an obvious
truth or admitting I am right?



If so, which of the four laws do you think don't give the right
predictions?


You may not like the word "aether" but the cap fits, so wear it.



You didn't answer my question. Are you avoiding it because you know
there is no way for you to answer without either denying an obvious
truth or admitting I am right?



and it has been experimentally confirmed.


You may not like the word "aether" but the cap fits, so wear it.


What has been experimentally confirmed, old son, is that the speed
of light in a vacuum is source dependent, billions of times by
thousands
of stars.
And YOU are walking around with you head in a book instead of
looking up, telling me I'm wrong, your book says so. I'm looking
at REAL data, EMPIRICAL data


Data which can be easily explained by an alternate theory, without
throwing out existing equations that have mountains of REAL and
EMPIRICAL data supporting them. Do you want me to explain all the
REAL and EMPIRICAL experiments which can be done to test each of
Maxwell's, or do you agree that there's a lot of evidence for them,
even if you hold out faith that somehow we will be able to modify
them in a way that still agrees with these experiments but that no
longer predicts the velocity of electromagnetic waves is independent
of source velocity?


You may not like the word "aether" but the cap fits, so wear it.
Androcles




You didn't answer my question. Are you avoiding it because you know
there is no way for you to answer without either denying an obvious
truth or admitting I am right?

Jesse

"Jesse Mazer" wrote in message
...


Androcles wrote:

"Jesse Mazer" wrote in message
...

Androcles wrote:


Define "rest frame". To Einstein and Michelson it meant the rest of
the
Universe, with the Earth in motion about to the sun. Of course
Michelson
and Einstein didn't know the Milky Way was a galaxy back then,
galaxies
were called "nebulae", meaning clouds. The sun was still the centre
of the Universe. It was the Earth's motion through the "rest frame"
that was being
used by MMX to find the speed of light in the "rest frame".


When Einstein used the words "rest frame" he just meant "the frame in
which a given observer is at rest".


Fine. Put the observer on the moon with a telescope watching MMX.
I guarantee he'll see no fringe shift.


Yes, this is what SR predicts, because it says the speed of light is
the same in all directions, regardless of whose rest frame you're in.

Take it back to the funny farm.
Androcles.





For example, if I drive by you at 60 mph relative to the ground, in
my rest frame it is the car which is at rest and you who are moving
backwards at 60 mph. The concept of each observer having a rest
frame is used in Newtonian mechanics as well.


Fine, put MMX in the car, and I guarantee a pedestrian will see no
shift.


Again, SR predicts the speed of light will be the same in all rest
frames, both the car's rest frame and the pedestrian's.




Michelson-Morely thought there was a special frame, the rest frame of
the aether, in which light travelled at the same speed in all
directions. But Einstein didn't believe that, of course--he thought
that light travelled at the same speed in all directions in *every*
observer's rest frame.


It takes half the time of the round trip A to B and back to A
again as it does to get from A to B, even when A is racing toward B.


Only if B is also racing away from A, such that the distance between
them remains constant. And the time will only be equal in the A-B rest
frame, in other frames the time from A to B will be different than the
time from B to A.



So when Timo said "The analysis is _simplest_ in the rest frame", I
think he just meant the rest frame of the apparatus, not some
universally special reference frame.


In other words the velocity of light is c+ 60 mph in your car,
as seen by the bystander, because the car is the rest frame.


That doesn't make any sense--"as seen by the bystander" means you are
making your calculations from the bystander's rest frame. It's not as
if the bystander is obligated to use the car's rest frame just because
the apparatus is in the car--any physical situation can be considered
from the standpoint of whichever rest frame you choose. And whichever
you choose, the velocity of light will equal c in that frame. For
example, the bystander will see the light take longer to get from one
end of a moving tube to the other when the light is moving in the same
direction as the tube as when it's going in the opposite direction,
since he sees it going c both ways.

If you don't believe me, I can calculate the coordinates of the events
(light sent out from back end of tube), (light reaches front end of
tube), and (light returns to back end of tube) in both the car's rest
frame and the observer's rest frame, using the Lorentz
transformations. I suspect you already know what the result will be,
though.

Jesse

"Timo Nieminen" wrote in message
news:Pine.LNX.4.50.0501131046550.18896-100000@localhost...
On Thu, 13 Jan 2005, Androcles wrote:

"Timo Nieminen" wrote:
On Wed, 12 Jan 2005, Androcles wrote:
"Timo Nieminen" wrote:
On Wed, 12 Jan 2005, Androcles wrote:

I will now give the proof.
I place two identical evacuated tubes at right angles, with
mirrors
and
with
sources and detectors of light.
When the light reaches a detector, it turns off the source.
When NO light reaches the detector, it turns the source on.
The path length can be any reasonable one.
I connect the outputs of the detectors to an up/down counter,
one
for
up
and the other for down. I calibrate the tube lengths until
there
is
no
count.
I now have MMX, electronic version and air free.

Since your original assertion was specific to MMX, I'll first
deal
with
the actual MMX. Then your modified experiment.

I rotate the apparatus 90 degrees and what happens? NO count
happens.
Acording to SR, and there being velocity as the Earth moves and
rotates
x' = (x-vt)/ sqrt(1-v^2/c^2)
y' = y.
So, x' does not equal y'.

Why would you want to analyse the experiment using a reference
frame
moving wrt the Earth?

Simple, really.
If you analyse it from a frame that is at rest, you prove nothing
at
all.
Hence we analyze from a relatively moving frame. Get your
telescope
out and watch the fringe shifts from a plane if you like. As you
look
at Michelson's light, you'll notice it is doppler-shifted. Stay at
rest
and
you won't.

Your modified version makes Doppler shifts irrelvant - you can
ignore
the
wavelength and frequency, and only the speed matters.

Exactly. Well done. To use Einstein's own words, the "tip of the
ray".
Nobody is really interested on the following wave train, but that was
all
Michelson had.

So why bring up Doppler shifts?
If you knew they were irrelevant, why introduce them into the
discussion?

Me? If I recall correctly, you were the one that was bleating about the
old interferometer. I was introducing an electronic version. That's how
it got into the discussion.



Analysing it in a frame where it at rest proves everything that is
required.

Of course it does. The tip of the ray is travelling at c relative
to the source.

So, you agree that the rest-frame analysis proves everything that is
required?

Put the experiment on a plane, and the speed of light in the plane is
c.
To an observer outside the plane on the ground, it is c+v.
Hence the speed of light is source dependent. Why are you
arguing about it, you already agreed, right?


An analysis using any theory that is compatible with
the PoR allows us to use any reference frame.

There you are, then. You've answered your own question.

No, I haven't. The analysis is _simplest_ in the rest frame. The
question
was why not use that rest frame?

Define "rest frame".

A reference frame where the MMX apparatus is at rest.

Ok, so the speed of light is source dependent. The ground is moving
beneath the plane.


To Einstein and Michelson it meant the rest of the
Universe, with the Earth in motion about to the sun.

Perhaps to Michelson. Not to Einstein.

Crazy Einstein thinks the time to get from A to B is half the time
it takes to get from A to B and back to A again.
London to New York - 7 hours against the jet stream.
New York to London - 6 hours with the jet stream

2AB/(t'A-tA) = speed, so
(tau0+tau2) / 2 = tau1
(7+6)/2 = 7, right?

Obviously I'm discussing physics with someone that belongs
in a straight -jacket.
Have a nice day.

Androcles.

Ah, see, and I was assuming you were out of town on pressing business.
Are you coming back to resume our discussion?

PD

Androcles wrote:
Crazy Einstein thinks the time to get from A to B is half the time
it takes to get from A to B and back to A again.

For light, so long as A and B are stationary with
respect to each other, this is true.

London to New York - 7 hours against the jet stream.
New York to London - 6 hours with the jet stream

Perhaps you aren't aware that AIRcraft (note
name) are affected by the JET STREAM (note name)
because they propel themselves through the AIR.
Thus, the motion of air will affect their ground
velocity, which is the vector sum of the aircraft's
motion relative to the air (called "airspeed" in the
US) and the velocity of the air relative to the ground.

Light speed is not affected by wind. Did you think it was?

2AB/(t'A-tA) = speed, so
(tau0+tau2) / 2 = tau1
(7+6)/2 = 7, right?

I don't recall Einstein discussing flight times of
jets in 1905. That would have been even more prescient
than his prediction of gravitational lensing later,
don't you think?

- Randy