posted 11-02-2000 02:20 PM              

Over the past several years, discussions have arisen in which some people see aircraft creating white trails in the sky, some people call these "chemtrails", which they distinguish as being different from normal contrails.

At one website discussing the phenomena, there is a discussion forum which has been the site of lively debate over the various issues.
At this discussion, I proposed that we formulate questions for submission to known experts in various fields, and ask for their input
in answering the questions. The moderator and several participants of the discussion group have agreed that this process will be a valuable
way to find authoritative sources with experience and specific knowledge of the subject.

Since the current questions regard the optical phenomenon sometimes seen, which you probably are familiar with, you have been one of several chosen to answer these questions, which are listed below.

In reference to these questions, it will be helpful for you to peruse this website, especially the images provided there, which illustrate some of the optical effects we are asking about, which are found in the quickview window listed as "visual phenomena".
main image database: http://www.chemtrailcentral.com/imgdb/

In order to respond to the questions, you will need to enter the discussion forum at: http://www.chemtrailcentral.com/cgi-bin/forumdisplay.cgi?action=top ics&forum=Chemtrail+and+Related&number=1
where you can create a username and password, then post your message under the topic "OPTICAL EFFECTS QUESTIONS".

We certainly look forward to your input on these questions, and thank you in advance for your time and consideration.

Sincerely,
Jay Reynolds
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Questions submitted:
1. Are ice crystals in a contrail..opaque or semi-opaque?

2. Are the refractive properties of a semi-opaque ice crystal different than the refractive properties of a liquid droplet?

3. If these properties of refraction are different, then what visual efects can be expected when light is passed through a cloud of semi-opaque (assumed) ice-crystals as opposed to a mist of liquid droplets.

4. If we see a rainbow effect in an airborne mist, for example, can we thereby make a judgement as to the composition of the mist (whether it is composed of water droplets or ice-crystals) by the visual color signature determined by its particulate refractive properties.

5. What is your evaluation of the following statement:
Fact 2: Chemtrails have unusual refractive properties producing a rainbow or oil slick effect not found in the opaque ice crystals of normal contrails.

6. Which crystal habits have been observed within ice crystals formed by normal contrails?

7.Have the optical effects being described in the photos referenced
always been present in normal contrails?

8.Have there been any trends established over time for frequency of the optical effects displayed in the photos referenced, have they become more frequent, remained steady, or decreased?

9.One researcher who contends that a barium salt is being released by "chemtrails" has been using a visual light prism spectroscope, pointing towards the sunset, and says he detects wavelengths indicating barium, is there validity to this methodology, or is there another possible reason for what he claims? (see: http://www.carnicom.com/spectra1.htm)

posted 11-02-2000 05:24 PM            

I too, am satisfied with these questions, however, I have a few more.

11. I would like to know the spectral analysis of viewing a full spectrum rainbow, seen while facing the sun, and/or on either side of the sun.

12. What is the result & cause of viewing only shades of magenta and green refraction within jet plumes or clouds during high noon.

posted 11-02-2000 08:21 PM            

In brief, contrails form from homogeneous or heterogeneous nucleation when atmospheric conditions are such that the relative humidity high and the vapor pressure with respect to ice is high. When a perturbation occurs such that particle surfaces are presented on which water vapor can condense and freeze, partticles form that are called contrails. These particles can be water, but normally they remain liquid for only a brief time before they freeze and grow as ice crystals. The length of time that these contrails exist is solely a function of the atmospheric humidity.

To answer some of the questions you asked:

1. Are ice crystals in a contrail..opaque or semi-opaque?
This depends upon the relative temperature and humidity. The combination of these two factors determines the ice crystal type that forms and grows. I would say that in most cases the crystals are opaque as far as transmitting light. They do scatter light, however, with an angular dependency that is a function of the shape and size.
2. Are the refractive properties of a semi-opaque ice crystal different than
the refractive properties of a liquid droplet?
Yes, very much so. The coronal you see from an ice cloud is quite different from the rainbow of a water cloud.

posted 11-04-2000 04:30 PM            

quote:

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I have doubts that the person who posted was any of the guests I invited.

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I confirmed by IP that Darrel is associated with UCAR. He is one of your invited guests.

posted 11-04-2000 09:47 PM              

Translucent materials permit some light to pass through them, but the light is scattered.

Opaque materials absorb all the colors of white light except their own, which they reflect. Only the surfaces of opaque substances are visible. Light cannot pass through them, and it is not possible to see through them. Opaque substances either absorb or reflect light.

The ice crystals known to produce the prismatic effects do so through refraction, which occurs when the light enters one side of the crystal and exits another. To do so, these crystals must be transparent. I do understand that they are seldom "perfect", and have do have flaws, but these crystals are not opaque. No way.

Jay Reynolds

posted 11-04-2000 11:58 PM            

Your ice crystal expert seems to think otherwise Jay.

Cy, I might invite a friend to a party, and he may be a 49er's fan.....he's still a friend , even though I HATE the 49er's...you get it..????

Seems a guest was invited ..gave their 2 cents and booked it...

I'll go with the post below....

>canex
Member
Posts: 13
From:USA
Registered: Oct 2000
posted 11-02-2000 10:24 PM
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Dr. B'g'ner:
Are you saying that if you had an ice crystal from a contrail and placed it under a backlit microscope, that you would be unable to see through that crystal? I.e., it is opaque? Are you saying that ice crystals in contrails and cirrus clouds do not transmit light through them?
Certainly, they scatter light as any particle scatters light, but do they not transmit light? They do not absorb visible wavelength light, and the amount of light passed through and diffracted around them exceeds the amount scattered back. The crystals themselves are clear as an ice cube is clear. The cloud becomes opaue because of multiple scattering by the ice crystals, not because the ice crystals are opaque.<