Re: The motion of waves

From: bz (bz+sp_at_ch100-5.chem.lsu.edu)
Date: 03/27/05 

Date: Sun, 27 Mar 2005 16:06:46 +0000 (UTC)

"jahn" <susysewnshow@yahoo.com.au> wrote in
news:3ao023F65gui7U1@individual.net:

>
> "bz" <bz+sp@ch100-5.chem.lsu.edu> wrote in message
> news:Xns962655B0EC4B4WQAHBGMXSZHVspammote@130.39.198.139...
>> "jahn" <susysewnshow@yahoo.com.au> wrote in news:3anq8aF6c9vi6U1
>> @individual.net:
>>
>> > Is their like... some kind of choreographer to keep all of the
>> > photons in step... or cadence... or whatever you call it?
>> >
>> > Sue...
>> >
>>
>> If they are generated 'in step', as in a laser, they stay in step. This
>> is called phase coherence.
>
> I don't think lasers exist naturally do they ? Maybe short ones.

That is a good question. It is possible that the 'jets' of energy and
matter that are seen coming from collapsing star(s) might be a similar
phenomina. You have a lot of ions confined by a magnetic field.

>>
>> If the E field points in the same direction, they are plane polarized.
> How do atoms "point the same way" ?
>>
>> If the EM fields rotate as the photons travel, the photons are
>> circularly polarized.
> Circular... you mean like the shape of an atom?

No [what makes you think atoms are circular?]. I mean that the wave/photon
spins about an axis that represents its direction of travel, like a bullet
spins around an axis that is parallel to its direction of travel.

Lets look at microwave photons. They can be launched from a 1/2 wave
dipole. In which case the receiving antenna dipole should be parallel to
the transmitting antenna dipole. If it is perpendicular, most of the signal
is lost. If the dipole is aligned vertically, the wave is said to be
vertically polarized. If the dipole is aligned horizontally, the wave is
said to be horizontally polarized because the 'E field' oscillates in the
horizontal plane.

An antenna can be constructed with a 'corkscrew shaped antenna'. This will
launch a 'circularly polarized' signal. The wave/photons can rotate either
clockwise or counterclockwise, depending on how the antenna is constructed.

Light can also be plane polarized or circularly polarized. Some chemicals
line up in patterns that filter out plane polarized light in one plane.
Polaroid sunglasses use such a material.

Some chemicals allow light that is circularly polarized in one direction to
pass and filter out the other orientation. Such filters are used in some
liquid crystal displays. If you put on your polaroid sun glasses and look
at a liquid crystal display and the image on the display disappears when
you turn your head at a certain angle, then your display uses plane
polarized filters. On the other hand, if the tilt of your head does NOT
make the image go away, your screen uses circular polarization.

>>
>> photons emitted by a hot surface, like a light bulb are neither
>> coherent nor polarized.
>
> Are hot surfaces made of atoms ?

Depends on how hot the surface is. But as long as it is a 'surface' it is
made of atoms.

If you get matter hot enough, the atoms lose electrons and become ions.
They are still atoms, just excited ones.

If you get matter even hotter and put it under enough pressure to keep it
together, the protons and electrons can combine to form neutrons. THEN you
have no atoms, you just have a mass of very hot neutrons.

> Self deprication will get you every-where ;-)

I have yet to be every-where. :}

There is also the implication that we are ALL ignorant and have something
worth while to learn from each other.

I am SURE that there are things that YOU know that I do not know.

For example, what you had for breakfast this morning. :) 

-- 
bz
please pardon my infinite ignorance, the set-of-things-I-do-not-know is an 
infinite set.
bz+sp@ch100-5.chem.lsu.edu   remove ch100-5 to avoid spam trap

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