We all know that Michelson and Morly found that the speed of light is
always the same, even if the observer moves. This result puzzled many
scientists.

But how did they found that?

Their equipment was stationary on the earth, but the earth is in
motion - in orbit around the sun. This was the moving observer.

What light source did they use? Perhaps a lamp. In that case the light
source moved with their equipment. If the speed of light is always c
with respect to the light source, they would not be surprises if it
were c with respect to their equipment.

Or did they use a remote star? In that case the light passed through
the atmosphere, which might change its speed.

The latter can be explained as follows: A man runs with a speed of 10
km/h along a road. He overtakes a lorry which has a speed of 7 km/h.
An observer on the lorry will find that the man is running at 3 km/h.
The runner jumps on the lorry and continues running. The observer now
finds that the man runs at 10 km/h. This result does not depend on the
speed of the lorry.

Therefore I wonder why Michelson and Morley were puzzled when they
found that the speed of light does not depend on the obserer's speed.
--
Feico Nater

"Feico Nater" wrote in message
...
We all know that Michelson and Morly found that the speed of light is
always the same, even if the observer moves. This result puzzled many
scientists.

But how did they found that?

Their equipment was stationary on the earth, but the earth is in
motion - in orbit around the sun. This was the moving observer.

What light source did they use? Perhaps a lamp. In that case the light
source moved with their equipment. If the speed of light is always c
with respect to the light source, they would not be surprises if it
were c with respect to their equipment.

That doesn't work: Michelson and Morley had already tested before that with
respect to their equipment, light speed is not c/n relative to a moving
medium ("Fizeau effect").

Or did they use a remote star? In that case the light passed through
the atmosphere, which might change its speed.

See above: it was already inferred that light speed is not in general c/n
relative to the air.

The latter can be explained as follows: A man runs with a speed of 10
km/h along a road. He overtakes a lorry which has a speed of 7 km/h.
An observer on the lorry will find that the man is running at 3 km/h.
The runner jumps on the lorry and continues running. The observer now
finds that the man runs at 10 km/h. This result does not depend on the
speed of the lorry.

In the earlier experiment, and in your analogy, the observer on the road
sees the "runner" move at less than 17 km/h. The result does depend on the
speed of the lorry (replace "lorry" by "water"; and it's not a perfect
example due to the lack of an equivalent for "n").

Therefore I wonder why Michelson and Morley were puzzled when they
found that the speed of light does not depend on the obserer's speed.
--
Feico Nater

Harald

Feico Nater wrote:
We all know that Michelson and Morly found that the speed of light is
always the same, even if the observer moves. This result puzzled many
scientists.

But how did they found that?

Their equipment was stationary on the earth, but the earth is in
motion - in orbit around the sun. This was the moving observer.

What light source did they use?

They used the sun. Since unlike morons and
Quantum Mechaincs idiots they weren't
trying to prove anything about the speed of light.

This may seem incredible but they in fact used a candle. They needed to
exactly equal distances in the arms. With a laser you can have a
considerable path difference.

The experiment was performed at 6 monthly intervals where the speed of
the Earth would differ by 60km/s.

On Wed, 7 Dec 2005 15:22:05 +0100, "Harry"
wrote in sci.physics.relativity:

That doesn't work: Michelson and Morley had already tested before that with
respect to their equipment, light speed is not c/n relative to a moving
medium ("Fizeau effect").

What do you mean by 'c/n'? What is Fizeau?

The latter can be explained as follows: A man runs with a speed of 10
km/h along a road. He overtakes a lorry which has a speed of 7 km/h.
An observer on the lorry will find that the man is running at 3 km/h.
The runner jumps on the lorry and continues running. The observer now
finds that the man runs at 10 km/h. This result does not depend on the
speed of the lorry.

In the earlier experiment, and in your analogy, the observer on the road

My observer is on the lorry. A moving observer.

sees the "runner" move at less than 17 km/h.

Slightly less, but we do not know about relativity yet.

The result does depend on the
speed of the lorry (replace "lorry" by "water"; and it's not a perfect
example due to the lack of an equivalent for "n").

What is 'n'?

--
Feico Nater

On 7 Dec 2005 06:36:44 -0800, "
wrote in sci.physics.relativity:

They used the sun. Since unlike morons and
Quantum Mechaincs idiots they weren't
trying to prove anything about the speed of light.

The distance from the sun to the earth is almost constant. In this
case I would expect the same result as when I used a candle.
--
Feico Nater

On 7 Dec 2005 07:20:08 -0800, wrote in
sci.physics.relativity:

This may seem incredible but they in fact used a candle.

So the light source had the same speed as the measuring equipment. In
that case I would not have been surprised if I measured a constant
light speed. It means that the light speed is relative to the light
source, just as in Newtonian physics.

If I throw a ball during a train ride, the speed of the ball will be
the sum of the throw and the speed of the train. Any other passenger
on the train will measure the thrown speed only.

IOW: If M&M used a candle and they measured the same light speed every
time, they would conclude that apparently the speed of light is
relative to the light source.

The experiment was performed at 6 monthly intervals where the speed of
the Earth would differ by 60km/s.

Yes, that would be very sensible, of course.
--
Feico Nater

IOW: If M&M used a candle and they measured the same light speed every
time, they would conclude that apparently the speed of light is
relative to the light source.

No if that were the case we would see double stars very differently. We
see stars revolving round other stars and changing their velocity
according to gravitation. If light traveled with the source we would
see doubles receeding from us rapidly when they were in fact coming
towards us. In fact the light from a double star would be a blur.

No that theory was NEVER believed after the time of Newton.

"Feico Nater" wrote in message
...
On Wed, 7 Dec 2005 15:22:05 +0100, "Harry"
wrote in sci.physics.relativity:

That doesn't work: Michelson and Morley had already tested before that
with
respect to their equipment, light speed is not c/n relative to a moving
medium ("Fizeau effect").

What do you mean by 'c/n'? What is Fizeau?

n is the breakings index.
Fizeau was an experimenter who found that light speed was *not* fully added
to the speed of the medium. Michelson and Morley repeated his experiment.
They concluded that light is delayed by matter, but it is unaffected by
matter in the free space between the atoms, IOW light speed in free space is
unaffected by earlier interactions with matter.

The latter can be explained as follows: A man runs with a speed of 10
km/h along a road. He overtakes a lorry which has a speed of 7 km/h.
An observer on the lorry will find that the man is running at 3 km/h.
The runner jumps on the lorry and continues running. The observer now
finds that the man runs at 10 km/h. This result does not depend on the
speed of the lorry.

In the earlier experiment, and in your analogy, the observer on the road

My observer is on the lorry. A moving observer.

I referred to the earlier experiment. Any theory had to conform to that.

sees the "runner" move at less than 17 km/h.

Slightly less, but we do not know about relativity yet.

What counts is measurements.

Cheers,
Harald

The result does depend on the
speed of the lorry (replace "lorry" by "water"; and it's not a perfect
example due to the lack of an equivalent for "n").

What is 'n'?

--
Feico Nater

"Feico Nater" wrote in message
...
We all know that Michelson and Morly found that the speed of light is
always the same, even if the observer moves. This result puzzled many
scientists.

Do we? I didn't know that. Who's Morly?



But how did they found that?

They didn't.


Their equipment was stationary on the earth, but the earth is in
motion - in orbit around the sun. This was the moving observer.

What light source did they use? Perhaps a lamp.

Yeah, you could call it that.
I expect they used one of those new-fangled light bulbs Edison
was peddling.


In that case the light
source moved with their equipment.

Yep. Right on, guy.


If the speed of light is always c
with respect to the light source, they would not be surprises if it
were c with respect to their equipment.

Right. Well done.


Or did they use a remote star?

No.

In that case the light passed through
the atmosphere, which might change its speed.

It would indeed.



The latter can be explained as follows: A man runs with a speed of 10
km/h along a road. He overtakes a lorry which has a speed of 7 km/h.
An observer on the lorry will find that the man is running at 3 km/h.
The runner jumps on the lorry and continues running. The observer now
finds that the man runs at 10 km/h. This result does not depend on the
speed of the lorry.

How about he plays pingpong in the back of the lorry instead of running,
with the light as the ball?



Therefore I wonder why Michelson and Morley were puzzled when they
found that the speed of light does not depend on the obserer's speed.

Hmmm... Maybe they weren't. Maybe it was the idiot Albert Einstein that
wanted to puzzle you.

When asked if New York stops at this train, Galileo replied "Yes".

Einstein said "As has already been shown to the first order
of small quantities (by Galileo, but the secret to creativity
is knowing how to hide your sources so we won't mention him)
the same laws of mechanics will be valid for all frames of reference
for which the equations of electrodynamics and optics hold good.
We will raise this conjecture (the purport of which will hereafter
be called the "Principle of Relativity" so that it looks as if I
discovered it) to the status of a postulate, because everything
should be as simple as possible but not simpler and imagination
is more important than knowledge and if we knew what it was
we were doing, it would not be called research, would it and
as far as the laws of mathematics refer to reality, they are not certain;
as far as they are certain, they do not refer to reality and God
doesn't play craps, poker or roulette and he may be subtle,
but he isn't plain mean and I never think of the future, it comes
soon enough and what really interests me is whether God had any choice
in the creation of the world and if you are out to describe the truth,
leave elegance to the tailor and a table, a chair, a bowl of fruit
and a violin; what else does a man need to be happy and it would be
possible to describe everything scientifically, but it would make no
sense and common sense is the collection of prejudices acquired by age
eighteen and God does not care about our mathematical difficulties; he
integrates empirically and the whole of science is nothing more
than a refinement of everyday thinking and do not worry about
your difficulties in Mathematics, I can assure you mine are still
greater and two things are infinite: the universe and human stupidity;
and I'm not sure about the universe"

Androcles.