What is 'Chaff'? I wondered that as well. It is often offered up as the explanation of these strange trails we see in the sky. Being the curious gal I am, off I went to find out about chaff. Below is a really good concise definition:
Chaff - Radar Counter measures
Chaff and flares are defensive mechanisms employed from military aircrafi to avoid detection and/or attack by adversary air defense systems. Chaff consists of small fibers that reflect radar signals and, when dispensed in large quantities from aircraft, form a cloud that temporarily hides the aircraft from radar detection. The two major types of military chaff in use are aluminum foil and aluminum-coated glass fibers. The aluminum foil-type is no longer manufactured, although it may still be in use.
When ejected from an aircraft, chaff forms the electromagnetic equivalent of a visual smoke screen that temporarily hides the aircraft from radar. Chaff also serves to decoy radar allowing aircraft to maneuver or egress from the area. It consists of small, extremely tie fibers of aluminum or aluminum-coated glass that disperse widely in the air when ejected from the aircraft and effectively reflect radar signals in various bands, in order to create a very large image of reflected signals (“return”) on the radar screen. In the air, the initial burst from a chaff bundle forms a sphere that shows up on radar screens as an electronic cloud. The aircraft is obscured by the cloud, which confuses enemy radar. Since chaff can obstruct radar, its use is coordinated with the Federal Aviation Administration (FAA).
There is also a handy list of the various types and uses of chaffs just to the right of the above citation.
Another one I found is Contrail Facts put out by the US Air Force. It is an interesting read. If everything discussed in the above document can explain these lingering patterns in the sky I still find it rather concerning as to the vast amount of pollutants themselves.
From the above pdf:
Chaff and flares are defensive counter measures used on aircraft to confuse radar and heat seeking missiles. Chaff is used as a decoy for radar seeking missiles and is made of glass silicate fibers with an aluminum coating. The fibers are approximately 60% glass fiber and 40% aluminum by weight. The typical Air Force RR-188 chaff bundle contains about 150 g of chaff or about 5 million fibers. The fibers are 25 microns in diameter and typically 1 to 2 cm in length. In 1997, the Air Force used about 1.8 million bundles worldwide. The amount of chaff released worldwide by all of the services is approximately 500 tons per year. Chaff falls to the earth at a settling velocity of approximately 30 cm per second. Atmospheric residence times range from 10 minutes for the majority of chaff released at 100 m to approximately 10 hours for chaff released at 10,000 feet. Chaff fibers experience little
breakup before reaching the ground.
So, there you go. I must say however, that I doubt that these trails are 'chaff'. One would imagine that if that is what they are, it wouldn't be an issue to just tell folks that. Although, needless to say the idea of these particulates raining down onto me isn't truly inspiring either.
I know that others may have seen the below article before, but I'll link to it just in case:
From the Idaho Observer 2006
Last May a family in Iowa contacted the office of Sen. Tom Harkin (D-IA) to report the constant criss-crossing of "chemtrails" in the sky above their neighborhood. They received back from the senator’s office a General Accounting Office (GAO) report on "military chaff" and the material safety data sheet for aluminum-coated fiberglass fibers being spread—seven days a week for several hours each day—in the skies above their home.
Having the fallout tested the lab reported back with this analysis:
6 bacteria, including anthrax and pneumonia
9 chemicals including acetylcholine chloride
26 heavy metals including arsenic, gold, lead,mercury, silver, uranium and zinc
4 molds and fungi
Hmmmm.... well it seems to me that chaff doesn't really explain this phenomena.
I'll keep digging, though I don't expect there is one really good answer. This spraying most likely has many more than one explanation, and where the truth may be is anyone's guess at this time.
As far as my neck of the woods, it's been rather quiet lately with the trails. I've seen a few, but FAR less that during the month of October. Which, if these were normal contrails following regular flight paths should not happen.
So, the mystery continues.