From: "Jerald F. Wright" 
To: atm{at}shore.net
Reply-To: "Jerald F. Wright" 


    I Think I Understand. It seems like it depend on where you observe the
waves.  In  a telescope you observe at the image plane. Ought not have
unwanted intersecting rays there.  Baffle that tube and drawtube.

Jerry



Frank Q wrote:

> Hi All
>
> Some food for thought ......
>
> Speaking from a PURELY CLASSICAL STANDPOINT,
>
> * waves can and do intersect.
>
> * but be careful how you use the term "interact"!
>
> If a wave interacts with something, (eg the rods and cones in our eyes) you
> would expect the wave to change that something (eg induce chemical or
> electrical changes). After all it is an electrical signal and not light that
> is
> processed by our brains.
>
> If a wave interacted with another wave then you would expect to be able to
> observe
> the results of this interaction, like a change in the characteristics of
> the wave such as its frequency. Thus we should be able to observe this
> response in two intersecting laser beams. Obviously this is not oberved
> (unless your standpoint is not purely classical- which leads to QM effects
> like electron-photon scattering and related phenomena).
>
> Now for effects like interference --- Interference is the LINEAR
> SUPERPOSITION
> of  two or more waves in a region of space. You may call this an
> "interaction" if you
> like. However, the waves are not changed in any way. What are changed are
> the
> resultant electric and magnetic fields in that region of space. (yes, you
> could say the
> waves are altered - but the effect is temporary). If we place a piece of
> paper
> there, we observe the bright and dark bands characteristic of an
> interference pattern.
> This is the way the paper responds to two or more waves impinging on it - it
> "emits"
> (this may not be the most appropriate term) radiation according to the
> resultant electric
> field which exists at the surface of the paper - ie the linear superposition
> or vector
> sum of the fields from all the waves impinging on it.
>
> Hope I have confused everyone
>
> Cheers
>
> Frank Q
>
> ----- Original Message -----
> From: "Dwight K. Elvey" 
> To: 
> Sent: Tuesday, January 21, 2003 9:10 AM
> Subject: Re: ATM intersecting light
>
> >
> > Hi
> >  Intersting observation. If there were a problem, we'd have
> > a hard time seeing anything. My understanding is that the
> > waves only interact when the medium becomes non-linear.
> > Of course, as another mentioned, there is a continuous
> > interference that is right where the beams cross. Since
> > these waves have different directions of travel and there
> > is no non-lenear interaction, when the waves energies
> > go out of the interacting area, they continue as though
> > the other wasn't there. I've seen this demonstrated
> > in a water wave tank at one time. If both were at the
> > same frequency, there were a lot of funny standing wave
> > effect where they crossed but out side the intersection,
> > the waves went on there original coarse.
> >  Air takes a really high energy level before non-lenearity
> > is much of an issue. These are tricks used in LASER work.
> > There are solid materials that have non-linear effects that
> > are used for such things as frequency doublers.
> > Dwight
> >
> >
> > >From: "A. Suykerbuyk" 
> > >
> > >Hi,
> > >
> > >Everywhere in the universe light is coming from all directions,
> intersecting
> > >is normal.
> > >
> > >Regards,
> > >Adrie Suijkerbuijk.
> > >
> > >-----Oorspronkelijk bericht-----
> > >Van: Harold 
> > >Aan: ATM 
> > >Datum: zondag 19 januari 2003 21:30
> > >Onderwerp: ATM intersecting light
> > >
> > >
> > >>
> > >>
> > >>
> > >>  In a typical newt. telescope, the incoming  light hits
the primary
> mirror
> > >>and is reflected back to the secondary and is then
diverted to cross
> > >through
> > >>the incoming beam. This probably sounds rediculus, but i find it
> facinating
> > >>how this intersecting doesn't somehow interfere with the optical
> image.If
> > >>light is invisible then how can we see it. If it's not invisible
> then....
> > >>humm, perhaps someone with a better understanding of
light and optical
> > >>properties could enlighten ( no pun intended) me.
> > >>
> > >>  Harold
> > >>
> > >>
> > >
> > >
> > >
> >
> >

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