CDR: Re: Re: Choate physics again
Wasn't it grounding and Maxwell's equations last time? I can't believe I'm falling for this again but here goes...
On Thu, 28 Sep 2000, Michael Motyka wrote:
By the time the coherent radiation (needed to make an image) passes
Were not talking holograms, Jimmy-boy
I didn't get the original message so I'll reply here.
Actually I didn't write this ^ I wrote this : I think what he was trying to convey were the effects of reflection, absortion and diffusion. etc...
No, we're not talking about lasers. But then again 'coherent' simply means 'arranged' or 'synchronized'. If you don't believe there is coherence in imaging the rays of light through a camera then you don't have a fucking clue about optics.
I am not an optics expert but I DO have a clue. And any coherence in the light that hits the film in my Canon as I snap one poorly composed photo after another is purely accidental unless the scene has been painted by a targetting system. What is a laser Jim? LASER Light Amplification by the Stimulated Emission of Radiation An atom in an excited state, ie one that is not in the ground state, may be stimulated to release a photon by an incoming photon. The most interesting part of this is that the emitted photon after the interaction is in phase with the incoming photon and in the same direction. Get lots of these interactions taking place in the right medium and you get a river of photons all in phase. That's what coherent means in optics - in phase. Check your Webster's and please read the definition that says "3. Physics. ..." Go to any optics book. Want references? Thermal radiation ( what you are imaging with your snooperscope ) is not coherent by any definition that I know of.
The fact is, that if you take a lens and form an image there IS most certainly a level of coherence. You can break that coherence by simply injecting a fogged piece of glass for example.
You could say that light and an optical system form a "coherent" image because the image is recognizable but that usage might be confusing because of the common and accepted use of coherent with reference to LASER light. Form an image is probably adequately descriptive.
This is what the walls of the house do, they break the coherence of the original light rays so that no image can be formed on the other side of the wall.
The walls of the house do not "break the coherence." The more interesting processes that would be going on at and in the walls of the house would be reflection, scattering, absorption, diffusion( thermal) and reradiation. These effects would probably vary widely with construction materials and wavelength. The end result as these wavelengths are incident on a wall might vary from little or no effect, through blurring to outright shielding.
Glass howerver is reasonably transparent and as a result the light doesn't lose coherence through that. However if you attenuate the light using an aluminized mylar sheet and then break up the image using the bubble pack (the little bubbles of air absord the IR and then re-emit it out of phase with the original stream of photons - that! is coherence), walah. No usable image the cops can use against you.
What your talking about is reflection, scattering, absorption etc...the coherence of the light don't enter into it.
[Rest of a dumbass rant from another party deleted]
Go back to your physics boooks Jim. You missed it again on this one. Damn I could kick myself for even trying. Mike
On Thu, 28 Sep 2000, Michael Motyka wrote:
Wasn't it grounding and Maxwell's equations last time? I can't believe I'm falling for this again but here goes...
No, that was Tim's fucked up physics. He was the one claiming Gauss's Law didn't apply and charge didn't reside on the outside of objects made of conductors.
Actually I didn't write this ^
I didn't say you did, I only cut the quote out of somebody elses reply. If it's mis-appropriated you should bitch at them. I made a clear note that I had NOT seen the original and was replying to a copy. Get your facts straight.
I think what he was trying to convey were the effects of reflection, absortion and diffusion. etc...
Those are mechanisms that lead to the loss of coherence of the photon emissions from the original source. You're confusing cause and effect.
I am not an optics expert but I DO have a clue. And any coherence in the light that hits the film in my Canon as I snap one poorly composed photo after another is purely accidental unless the scene has been painted by a targetting system.
Bullshit. If the photons that come off the reflected or secondary source are distrupted in their phase then no recognizable picture will form.
What is a laser Jim? LASER
Light Amplification by the Stimulated Emission of Radiation
Yeah, so where in 'coherence' in there? I know what MASER means too.
An atom in an excited state, ie one that is not in the ground state, may be stimulated to release a photon by an incoming photon. The most interesting part of this is that the emitted photon after the interaction is in phase with the incoming photon and in the same direction.
No, it is NOT in phase with the incoming photon. It IS in phase with the secondary photons emitted by the material in the lasing body. In general the optical pump for a laser is a optical flash and it emits no recognizable coherent photons.
Get lots of these interactions taking place in the right medium and you get a river of photons all in phase. That's what coherent means in optics - in phase.
Exactly. And if the photons are not coherent with respect to arrival time and flight path when you try to take a photo then no picture will occur. Instead you get a blob. Note that I am NOT saying the photons are coherent with respect to their individual waveshapes (ie peaks/vallies match) but rather that their emission and arrival time are coherent, they happen at the same time and follow rougly parallel paths (now do you get it, I didnt' think so.).
Go to any optics book. Want references?
No thanks, I've got quite a few right here. Beside that I've spent the last 30 or so years building this sorta shit. Study nature, not books. Louis Agassiz
Thermal radiation ( what you are imaging with your snooperscope ) is not coherent by any definition that I know of.
Yes, it is time-coherent as well as path-coherent (they must be parallel in order to make a picture). The wall does two things: It causes the photons emitted at the same time from the source to be received at different time, this interupts the ability of the receiver to correlate (i.e. verify coherence) them into a recognizable picture. The second thing it does is take the intialy parallel rays of light and break that parellelism, their coherence with respect to path (in other words their coherence with respect to geometry, lasers require this as well to laze, it's more than the emitted photons being in step, they have to be parallel also). The photons that are re-emitted from an intermediary barrier are NOT parallel (or coherent) with the original source photons. [more pseudo-science deleted] Coherent in physics means 'in phase' or 'in step', it does not mean 'in phase only with respect to individual wave equations'. There are LOTS of forms of coherence in physics that have nothing to do with lasers or even optics. Coherent means correlated with respect to some characteristic. Instead of reading about a laser, build a couple. ____________________________________________________________________ He is able who thinks he is able. Buddha The Armadillo Group ,::////;::-. James Choate Austin, Tx /:'///// ``::>/|/ ravage@ssz.com www.ssz.com .', |||| `/( e\ 512-451-7087 -====~~mm-'`-```-mm --'- --------------------------------------------------------------------
At 12:43 AM -0500 9/29/00, Jim Choate wrote:
On Thu, 28 Sep 2000, Michael Motyka wrote:
Wasn't it grounding and Maxwell's equations last time? I can't believe I'm falling for this again but here goes...
No, that was Tim's fucked up physics. He was the one claiming Gauss's Law didn't apply and charge didn't reside on the outside of objects made of conductors.
Choate lies. Nothing new. --Tim May -- ---------:---------:---------:---------:---------:---------:---------:---- Timothy C. May | Crypto Anarchy: encryption, digital money, ComSec 3DES: 831-728-0152 | anonymous networks, digital pseudonyms, zero W.A.S.T.E.: Corralitos, CA | knowledge, reputations, information markets, "Cyphernomicon" | black markets, collapse of governments.
On Fri, 29 Sep 2000, Tim May wrote:
Choate lies. Nothing new.
Prove it Tim, produce the email from the archive where I state that Guass's Law was not involved... No Tim, you do. Go back to the archives on that charge migration discussion and you will find an email from Tim, several days into it, stating that Gauss and such are not involved. You will then find an email about two days later where Tim then lies about the first email. ____________________________________________________________________ He is able who thinks he is able. Buddha The Armadillo Group ,::////;::-. James Choate Austin, Tx /:'///// ``::>/|/ ravage@ssz.com www.ssz.com .', |||| `/( e\ 512-451-7087 -====~~mm-'`-```-mm --'- --------------------------------------------------------------------
On Tue, 3 Oct 2000, Marcel Popescu wrote:
Huh? The photons from my TV screen arrive all at different times, and yet the picture is pretty good :)
No, they don't. The electron beam scans across your screen in a VERY tightly sychronized dance. Vertical retrace, horizontal retrace, etc. Each scan line data, etc. Television has all sorts of methods to sychronize the emission of photons. There is a sampling window issue here related to responce time of the eye as well. Then let's not forget that the rays your eye gets are all closely parallel also. If you think this doesn't matter play with a time delay and a television. Pay attention to standard high voltage technique. ____________________________________________________________________ He is able who thinks he is able. Buddha The Armadillo Group ,::////;::-. James Choate Austin, Tx /:'///// ``::>/|/ ravage@ssz.com www.ssz.com .', |||| `/( e\ 512-451-7087 -====~~mm-'`-```-mm --'- --------------------------------------------------------------------
Marcel Popescu wrote:
Huh? The photons from my TV screen arrive all at different times, and yet the picture is pretty good :)
No they don't, they arrive in order of the scanline, from the left edge to the right, then down a line, etc. (ducking flames.) :) -- ----------------------Kaos-Keraunos-Kybernetos--------------------------- + ^ + :Surveillance cameras|Passwords are like underwear. You don't /|\ \|/ :aren't security. A |share them, you don't hang them on your/\|/\ <--*-->:camera won't stop a |monitor, or under your keyboard, you \/|\/ /|\ :masked killer, but |don't email them, or put them on a web \|/ + v + :will violate privacy|site, and you must change them very often. --------_sunder_@_sunder_._net_------- http://www.sunder.net ------------
participants (5)
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Jim Choate
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Marcel Popescu
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Michael Motyka
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sunder
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Tim May