Hours of sunlight are recorded regularly, in fact.
By definition of "sitting around a cafe table", none are superimposed.
Arthur Dent.

Arthur Dent wrote:
You've just begun your understanding, just scratched the surface.


PD

Suppose a sundial that falls earthwards, making no motion east or west,
sliding down a square sectioned pole. For the purpose of the argument,
assume the sun is a point source of light and the shadow is sharp, able
to record time to any precision.
Does the shadow move, recording time?

As long as the pole base is fixed to the surface of the earth and
remains vertical (on a line radiating from the center of the earth),
yes, though the rate will be different than on the surface alone,
depending on the latitutude and how long it's been falling.


Three students are sitting around a cafe table. Their subjects are
physics, architecture and literature.
Andrew sits on the right of the architecture student. Brian on
Charles's right. What is the name of the architecture student?

Brian.

That is, until the sundial falls on his head.

what was it you added?

Suppose a sundial that falls earthwards, making no motion east or west,
sliding down a square sectioned pole. For the purpose of the argument,
assume the sun is a point source of light and the shadow is sharp, able
to record time to any precision.
Does the shadow move, recording time?



As long as the pole base is fixed to the surface of the earth and
remains vertical (on a line radiating from the center of the earth),
yes, though the rate will be different than on the surface alone,
depending on the latitutude and how long it's been falling.


Three students are sitting around a cafe table. Their subjects are
physics, architecture and literature.
Andrew sits on the right of the architecture student. Brian on
Charles's right. What is the name of the architecture student?



Brian.

That is, until the sundial falls on his head.

Well done.

Interesting, a sundial indicates a different time (angular position of
shadow) when at the equator than it does at the pole, and different
again when placed on a higher pedestal. ns I thought they all measured
15 degrees per hour. I guess Bilge was right, I really do need
geometry lessons.
Can you explain this for me please?
Arthur Dent

Then you would feel, he should find light quite slow (0.001% of
its original speed) This is the classical case. But now
the time-dilatation effects. The travellors clocks go exactly
so slow now, that from his point of view, light still goes with
full speed.

In the frame of the traveller the light goes from his tailpipe to his
nose cone, a distance of 3 meters, in a dilated time of 3.0/c = 1.0
E-08 seconds.
In the frame of the non-moving observer it travels from tailpipe to
nose cone, a distance of 300,000,000 meters, in one second, because the
nose cone is moving away from the light.

Is that what you are saying?

Arthur Dent.

On 2 Jun 2005 03:49:11 -0700, "Astroguru" wrote:

Fantastic !! Thanks alot guys !!

Now, I've got much more "light" on this area !!

As Oliver mentions :
This is the classical case. But now the time-dilatation effects. The travellors clocks go exactly so slow now, that from his point of view, light still goes with full speed.

That exactly answers my questions....... So, now due to the length
contraction everything would seemingly appear Flat and due to time
dilation everything would be standstill.... correct me if I'm wrong.
However, as the observer still measures the speed as being 'c',
would'nt he still see things moving and not standstill ??

Cheers,
Astro.

Congraulations Astro. You seem to have just managed to survive your first
brainwashing experience.
Whilst you agree outwardly, I can still detect doubts in your mind.

Don't listen to these people, they are totally dedicated to promotomg the
Einsteinian religion.

The truth is, light speed, like all speeds, must be specified relative to
another object.

All we really know is that light moves at c wrt its source, where c is a
universal constant.

One way light speed wrt any other than its source can have any value, depending
on relative source observer movement.

It is true that particles cannot be accelerated to greater than c in an
accelerator because the particle's own movement creates a reverse field that
reduces the effective force acting on it. It sets up what I call a 'reverse
field bubble' around itself in which all the input energy is stored.
The process is somewhat analogous to the back emf in chokes and motors.
It so happens that the equations describing the effect are identical to those
that predict a 'relativistic mass increase'. The particle behaves as though its
mass increases according to the LTs. In fact there is NO mass increase.

There is absolutely no evidence that Einstein's version of relativity is
correct.






HW.
www.users.bigpond.com/hewn/index.htm

Sometimes I feel like a complete failure.
The most useful thing I have ever done is prove Einstein wrong.

On 2 Jun 2005 01:07:30 -0700, "Oliver Brausch" wrote:

Hello,

Astroguru schrieb:
Further on, the theory of relativity also says that the speed of light
is independent of the reference frames.

like other told you, nbody can travel with light speed. But let us
consider this person goes 99.999% of light speed.

I feel that he should find that speed to be zero, as he himself is
moving at the same speed as the light beam.

Then you would feel, he should find light quite slow (0.001% of
its original speed) This is the classical case. But now
the time-dilatation effects. The travellors clocks go exactly
so slow now, that from his point of view, light still goes with
full speed.

Hope, I could help.

Rubbish. Nothing happens to the clocks.

Nothing can be accelerated to c in an accelerator for the reasons I have given
above.

A spaceship can never be accelerated to c because total available energy is
mc^2 and the KE at speed c is 1/2mc^2. The energy lost in accelerating it is
also theoretically at least 1/2mc^2.

On the other hand, atmospheric muons frequently exceed light speed because they
are created in massive collisions between energetic cosmic rays and air
molecules.



Dr. Oliver Brausch


HW.
www.users.bigpond.com/hewn/index.htm

Sometimes I feel like a complete failure.
The most useful thing I have ever done is prove Einstein wrong.

On 1 Jun 2005 07:32:06 -0700, "PD" wrote:

In a nutshell, the answer is that no massive object can move
at the speed of light...

Why on earth do even you learned folks continue to use language
which may be misleading and confusing, especially to SR newbies?
Instead of saying something like "No object can move at the speed
of light", say it this way: "No two objects can have a relative velocity
equal to the speed of light."

Some of you may think that the two statements differ only in nuance,
but I think that nuance is extremely important, especially for newbies.

Bryan

On Mon, 06 Jun 2005 11:17:05 GMT, H@..(Henri Wilson) wrote:

All we really know is that light moves at c wrt its source, where c is a
universal constant.

One way light speed wrt any other than its source can have any value,
depending on relative source observer movement.

How do you explain De Sitter's astronomical demonstration that
the speed of light relative to an observer cannot depend on the speed
of its source, relative to that observer?

Bryan

How do you explain De Sitter's astronomical demonstration that
the speed of light relative to an observer cannot depend on the speed
of its source, relative to that observer?

The universe is a dielectric gas. After a short distance from even a
moving emitter, the EM radiation must move at c wrt matter along
the path or it's energy will be absorbed.

http://scienceworld.wolfram.com/phys...onTheorem.html


Sue...