Contrail Science Welcome Guest | Login or Register

Executive Summary:

• Samples of water were collected in August 2007, in Stamps Arkansas, by leaving some bowls outside for a month
• The resultant dirty water was tested by KSLA and was found to have the same amount of barium in it as most municipal tap water.
• The reporter misunderstood the results, and said there was a lot of Barium

Some conspiracy theorists think that persistent spreading contrails indicate some kind of deliberate aerial spraying, probably by the government. They speculate as to what could be in these trails, and one of the most common things they claim is barium.

Some people are so obsessed by this idea that they have rainwater tested to see if it has barium in it. They usually find some, and then trumpet this as evidence that their theory is correct.

Unfortunately they are wrong. I’ll explain why, but first, some basic science. Continue Reading »

Some people think that persistent spreading contrails are somehow unusual, and are actually something dangerous being deliberately sprayed on the US people by the government, or perhaps for weather control purposes. They call these persistent contrails “chemtrails”.

Some of them are very insistent that this is a practically constant assault, saying the sky is never blue any more, and there are “chemtrails” constantly criss-crossing the sky.

Continue Reading »

I’ve talked about distrails and hole punch clouds before, but I’ve actually never seen one myself until this morning, when I saw two side by side. It’s quite rare to have this kind of weather condition in Los Angeles. I took a couple of photos at around 7:30AM today, Aug 19th, 2007. Santa Monica ATIS reports the sky is clear now, but Van Nuys reports broken cloud at 18,000 feet and 28,000,which is probably where these are, given they look like they are precipitating ice in artificial cirrus uncinus. The cloud layer that the holes formed is cirrocumulus.

Cirrocumulus clouds contain both ice crystals, and supercooled water droplets. The introduction of the extra water from the jet exhaust causes a rapid increase in the rate of crystallization, and all the water turns to ice as the ice crystals get larger. This rapidly desaturates the air, which then pulls in moisture from the air around it, thus spreading the hole. The larger ice crystals then drift downwards (as virga), since they are heavier, resulting in the characteristic “V” or “wing” cross-section of the central cirrus uncinus cloud, which looks a bit like a bird or an angel, if you are imaginative enough.

Continue Reading »

There was an interesting post over on the New York SkyWatch blog, which raised many of the common questions that people have about various contrail anomalies. I’ve attempted to answer all of the questions here:

Question #1, why [do] jet contrails appear as if the jet engine is being deliberately turned on and off?
It’s because the jet is flying through uneven areas of temperature and humidity. Explained here

Question #2, Explain why jet aircraft are leaving persistent contrails in grid patterns?
Because some jets fly north-south, and some east-west on airways that are several miles wide, and where they cross you get a grid. Winds at altitude blow at around 90mph, and these blow the trails across the sky, increasing the size of the grid.

Question #3, Shouldn’t the entire sky be filled with contrails? Would we ever see any truly blue sky again if all jets left persistent contrails behind?
Sometimes there are a lot of contrails, and they do spread out and cover the sky. Sometimes there are only a few. Sometimes there are none. It depends on the weather. There are only a certain number of jets flying overhead every day. They have to be at the right altitude for contrails to form. In some weather conditions this is limited to only the highest jets, or sometimes just jets in a narrow band of humid air. On very cold humid days you will see a lot of contrails, but no more than the number of jet at altitude.

Question #4, I know that contrails are formed under certain weather conditions and altitudes. However, there are times when conditions do not exist for contrails to persist?
Then they will not persist. The problem here is that it is incredibly difficult to know what the humidity is at a specific time, altitude and location. Humidity measurements are done by sending up a balloon every 12 hours from weather stations 300 miles apart, the balloon can be blown hundreds of miles in a random direction during its ascent. How can you get an accurate local humidity reading at a specific time and place from a balloon reading 6 hours ago and 300 miles away, when humidity can vary enough for contrails to form or not form in as little as half a mile (as you can see from the broken contrails), and humidity can vary by 50% over the course of a day?

Question #5, Certain contrails even look like they are laden with chemicals. You know the ones I mean. The ones that appear to drip by the weight of their own substance, mushrooming along the bottom edge of the trail. C’mon what’s in this stuff. It doesn’t even look like ordinary condensation to me?

They are called “pendules”, as seen in this pre-1991 photo, and described by Schaefer and Day in 1981. When a plane flies through the air at 500mph it creates wake turbulance, which is made up of wake vortices, (whirlpools of air), at regular intervals. These vortices make the contrail clump up in areas of greater and lesser density. In a dense persistent contrail, the vortices will produce the clumping pendules seen in the first photo. If the contrail is thin or not persistent, then they can leave interesting patterns which can resemble smoke rings. The type and visibility of the vortices will depend on the the size, shape and speed of the jet, as well as the turbulence and density of the air it is moving through.

Question #6, Speaking of abnormal, I have seen jets emitting contrails that are dark in appearance. I assumed that it might be the lighting conditions until I saw the black and white contrails side by side - check out this video?
I covered this in the “dark lines” article. It is the lighting conditions, the dark contrail is in shadow, and when you see contrails “side by side”, the lighter contrail could well be ten miles behind (or a mile above) the darker contrail, and so not in shadow.

Question #7, Another interesting aspect to these dark trails is that the material drifts to the ground in clouds that resemble the black smoke from a nearby fire. I have observed this process several times in the fall. I haven’t seen them since the beginning of the year?
Precipitation falling from clouds will look dark if it is in shadow, which is probably will be if the shadow is caused at sunset by a hill or cloud bank.

Question #8, And then there’s the other trails that appear to swallow up other trails and clouds. One of my YouTube videos shows this quite clearly. My first impression was that someone had a HUGE washcloth and scrubbed a portion of the sky. And then I saw jets going through the cloud mass and the contrails that were left created lines in the mass that expanded and left the cloud in sections.
This effect was observed in 1944, it’s basically a distrail, which is the opposite of a contrail, the cloud contains moisture, and the added moisture, particulates and turbulence of the jet passing through makes the amount of moisture in the air too great for it to exist as a cloud, so it precipitates as snow or rain. This wipes away the cloud where the contrail has been. This can also happen with cloud layers that are below the contrail, as precipitation from the contrail falls on the cloud layer. This is also known as “hole punch clouds” and “fallstreak holes“. Distrails can combine with the vortices of question 5, as in the photo on the right.

I hope I’ve answered all these questions. If you feel there is still something unclear, or you have extra questions, then please leave a comment below.

*UPDATE* Some more questions were raised in the comments, and I’ll add them here, with answers.

Question #9, On your website you have a picture of one jet leaving a “chemtrail” with another jet at the same altitude in the background is not leaving one. I have seen jets side by side and one leaving a normal contrail and another leaving a chemtrail?
There are two possibilities. either the jets are not at the same altitude, and just look like they are because of the viewing angle, or they have different engines with different exhaust characteristics. The more efficient an engine is, the more likely it is to leave a lasting contrail, as there is more water in the exhaust. The photo on the right shows an Airbus A340 (maiden flight: 1991) on the left, leaving contrails, and a Boeing 707 (maiden flight: 1957) not leaving contrails. Both are flying at 33,000 feet (part of a German test to study contrail formation), but the newer engines of the A340 produce more water vapor.

Questions #10, How do you explain pictures of aircraft spraying chemtrails from ports other than the engines?
It’s an optical illusion. The contrails come from the engines. Engine exhausts contain a lot of water, which (combined with the water in the air), condenses, freezes and causing the contrail. Because it’s hot when it exits the engine, it takes a fraction of a second to condense and freeze (in 40 below temperatures). So it begins to freezes about 100 feet behind the engines, which makes it look like it’s coming from the ends of the tail section. This illusion is stronger on a shorter two-engine plane - look at the inner engines on the picture on the left. Since it’s a four engined 747 (240 foot long), the contrails form before the tail section, but with shorter planes such as a 767-300 (180 foot long) the contrails would be forming about at the tips of the tail section when viewed from below (although they are actually well underneath the tail, as you can see in the close-up).

In very humid conditions, the turbulence caused by the aircraft itself can cause moisture in the air to condense, and hence freeze. This happens in areas of low pressure above the wing, and in the wingtip vortices, so you can get what looks like a solid sheet of contrail from the wing, and thin streamers from the wing tips (and maybe the tail), combined a bit further back with the engine contrails, as in the photo on the right. These low-pressure wing contrails can form at any altitude, given the right humidity, and account for the tales of planes landing “still spraying”.

Question #11, How do you explain scientists testing the fallout and finding aluminum, barium, nano particles, fungus, molds, viruses, etc in the mix?
They did not test contrails, they just tested some stuff they found on the ground, with no indication that it was connected with contrails (it would take several days for aerosolized matter to reach the ground, and by that time it would have been spread hundreds of miles from the original site). Most of the things they claim to have found are things that naturally occur in air and dirt.

Contrails are clouds made from water vapor that condenses then freezes behind a plane engine. Since the engines are on constantly, it seems a bit odd when you see contrails with gaps in them, or even contrails that stop and start. If the engine is pumping out a constant amount of water, then why is the trail not constant? This puzzle is sometimes seized on by people who think that persistent contrails are actually “chemtrails”, or some kind of deliberate spraying operation. Continue Reading »

People who think persistent contrails indicate some kind of conspiracy (which they call “chemtrails”), sometime point to the “dark lines” that sometimes accompany contrails. Since they can’t immediately think of why these dark lines should be there, they assume it’s part of the conspiracy. Either there is some kind of “dark chemtrail”, or the plane is projecting a dark beam of some kind of negative energy, or it is following a dark beam.

In reality these “dark lines” are simply the visual effects of shadows. There are actually three main kinds of dark line that are formed by contrail shadows.

Self Shadow - where the contrail itself is in shadow and appears dark. This can happen a number of ways. The sun can be low on the horizon and the contrail can be shadowed by a mountain or a thick cloud bank (such as in this video). In rare cases the plane can be flying directly towards the sun, and the contrail will shadow itself. When self-shadowing, the leading edge of the contrail will be brightly lit, with a dark area behind it. The photo on the right here shows some thick contrails (or possibly just row clouds) that are self shadowing. The sun has just set in front and to the right of the contrails.

Parallel Shadow - The contrail is simply casting a shadow on a layer of cloud beneath it. The cloud layer is thin enough so you can see through it, but it’s visible, so you can see the shadow on it. Theoretically you could cast a shadow on a cloud layer above or behind a contrail, if the sun were low enough, but this would be rather difficult to observe. Most “dark lines” are of this type. There’s an excellent explanation of these shadows over at Atmospheric Optics.

Edge shadow - The most interesting type of contrail dark line is when the contrail is lined up with the sun. This produces a slice of shadow through the atmosphere that looks like a dark line when viewed edge-on. It is quite difficult to visualize what is going on since you have to think in three dimensions, and we are accustomed to thinking of shadows as being flat, since they are usually cast on surfaces. You are not seeing a thin dark shadow here, you are actually seeing a huge slab of very faint shadow, but it’s viewed from looking along the edge. Imagine you have a thick sheet of glass. Viewed head on, it’s transparent, but if you look at it from the edge, it seems a lot darker.

The photo on the right is a rather dramatic illustration of this effect. The “dark line” here is caused by the slab of shadow cast by the portion of the upper part of the exhaust trail of the space shuttle Atlantis that is lined up roughly in a flat plane with the camera and the sun. The sun has just set, so the rays of the sun are almost parallel to the ground, so the upper portion of the plume is casting a long tall shadow through the air towards the horizon. This is viewed edge on from below, and so looks like a dark line. Since it’s a full moon, the sun is directly opposite the moon, so the “shadow” looks like it’s pointing at the moon (if you look closely, you’ll see it continues past the moon). This is particularly dramatic because of the combination of the setting sun and a vertical exhaust trail. With normal contrails, the sun has to be higher in the sky to cast the slab of shadow downwards.

[Math Warning] It’s a bit difficult to explain these edge shadows (also called volumetric shadows, or anticrepuscular shadows). You can think of them in terms of three dimensional geometry. The contrail is a line in three dimensional space. The camera (or observer) is a point in three dimensional space. The sun is essentially infinitely far away, and so is only really relevant as a directional vector (a vector in three dimensions, where the magnitude is unimportant ). These three quantities are what you need to consider to understand the condition for the edge shadow.

Given the line (contrail) and direction vector (sun) we can form a plane that contains the line, and is parallel to the direction vector. This plane cuts through the contrail, the atmosphere, and intersects the ground. Projecting two end points of the contrail along the plane in the direction of the sun’s vector, we get essentially a two dimensional parallelepiped (although the far edge is not very well defined). This parallelepiped is quite thin (it’s as thick as the contrail), so when viewed from the side, you won’t see much. But when the viewer is in the plane of the parallelepiped - specifically anywhere along the line on the ground formed by the intersection with the plane formed by the contrail and the sun - then they will be viewing the parallelepiped from edge-on, and so it will seem to be a dark line that intersects the contrail.

Since only the portion of the contrail that is roughly within this plane is contributing to the shadow, there may be other potions of the contrail that are not in the the plane, and hence do not seem to be casting a shadow. In fact they are, but since it is in a different plane, they are not visible unless the viewer was to move to a new position. This can be seen in the two photos above. In one it looks as if the plane was following a dark line, and then veered off. In the Shuttle photo, the highest portion of the trail, although brightly illuminated, is not contributing to the visible shadow. However a viewer in another location may have been able to see a different edge shadow trailing from this upper portion.

How high are those contrails? That’s a very important issue if you are investigating the science of contrail formation. I’ve been thinking for a while that a good method might be to take photos at a plane at a known focal length on a digital camera, and then by measuring the pixels of a known dimension of the plane (the length, or the wingspan), then you could calculate the height.

So I was delighted to find that someone had already done just this, in an article titled: “Points to Ponder: Calculate the altitude of aircraft using a digital camera“. They had worked out the math, and even given a little calculator.

Given this photo, which is an enlargement of the inset:

Continue Reading »

I’ve collected together a few photos of persistent spreading contrails from the past from 1991 back to 1940, just to show that this is nothing new, and that skies exactly like those shown on the “chemtrails” conspiracy web sites have been happening for the past 60 years. Mostly these are just photos I found on the internet, but several, like the first four, are scanned from books, so can be physically verified.

1991, From the book Peterson First guide to Clouds and Weather

Here are four photos of contrails, scanned from the book. You can see these photos on the Amazon page linked above. Click on the photos for larger versions. I suspect the actual date of these photos is pre-1991, but that’s certainly the latest possible date.

Continue Reading »

Several planes look a little odd, or have attachments that look odd, and so some people feel they must be part of a decades long conspiracy to spray stuff into the atmosphere to alter the weather or reduce the population. That’s obviously nonsense, but what are these strange planes?

Here’s one making the rounds, scary looking barrels, and a sign on the wall that possibly says “Hazmat inside”

What is it? It’s a Boeing 777-200LR Worldliner, specifically it’s WD001, a plane that was used for flight testing. The original photo can be found here - note the “Hazmat” text was added later.  The barrels contain water, which is pumped around to shift the center of gravity to test various flight characteristics.

From Boeing’s blog:

Remember, we test at the extremes of the weight/CG envelope. This requires us to control the CG during ground and flight conditions. We can move weight, in the form of water, forward or aft with the use of the water ballast system. This system is comprised of 48 barrels, each capable of carrying 460 pounds, connected by tubing to a pump. A computerized system tracks fuel placement, fuel burn, people placement, ballast, flap setting, landing gear position and water barrel quantity. The information is processed to display the airplane’s current CG. We move water or specify fuel tank usage to configure the CG within the specified test requirements.

Why are there overhead luggage compartments? It’s a test plane, and for FAA certification they have to demonstrate that everything works. That includes stuff like the emergency oxygen system, and more minor things like the luggage compartments. It’s a requirement that they don’t pop open in flight - so that needs to be tested. They are also handy for stowing the engineers’ stuff.

Here’s some pictures from Boeing:

And a lot more photos can be found on Boeing’s site.

——————————————————————————————–

This one gets a lot of use in the “chemtrail” forums:

Particularly because of the unusual collections of pipes sticking out in various places. There’s those two at the front, and then there is a group over the wing. Here’s some close ups

:

Very sinister looking tubes, but why are half of them facing the wrong way?

The plane is not for spraying the atmosphere, it’s for sampling the atmosphere. It’s a research aircraft, registration N701BN, operated by th e department of energy’s national labs. It’s pretty much one of a kind, so it’s hardly likely to be responsible for all the persistent contrails we see every day. The research is mostly on pollutants in the atmosphere, particularly from coal and oil burning power plants. But they also investigate the properties of clouds, which includes contrails.

————————————————————

Here’s another photo you see in “chemtrail” videos, with the implied suggestion that it’s some kind of evil spraying device:

Actually it IS a spraying device, but quite innocuous. It’s used by the air force to test icing of planes in flight. See:

https://www.safaq.hq.af.mil/news/march04/raptor.html

Here’s some more details:

nkc-135-icing-attachmentpv1983_2688.pdf

—————————————————————————————————

This plane is quite interesting:

It’s an E-6B “Tacamo”. This photo shows it dumping fuel (photo from tacamo.org). The E-6B is used by the United States Strategic Command as an airborne communication center. You can see the navy logo on the right wing. The E-6B is a modified version of the Boeing 707-320, and the fuel vents have been moved from the wing tips to between the fuselage and the engines in order to separate it from the communication equipment in the wing tips. This is what the wing-tip ESM/SATCOM pod looks like:

It looks like this odd assemblage is also creating some wingtip vortex contrails as well. The plane is pretty much all white, which is something you hear mentioned form time to time in “chemtrail” conspiracy theories.

Here’s another photo of the same plane, taken from a “chemtrail” YouTube video:

It shows the opening for the ELF trailing wire antenna. This is a very long wire antenna that is extended behind the plane for several hundred feet and used for communications with submarines.

—————————————————————————————————-

This plane also occasionally get brought up in chemtrail conspiracy groups:

This is obviously not a contrail, it’s far too low and the trail is dropping too rapidly.

It’s a Boeing 747-100 “Supertanker”, modified by Evergreen Aviation, the only one of its kind. Specifically designed for fire fighthing. That’s it dumping water.

Here’s a video of it in action, titled “B747 chemtrails”. It’s interesting reading the comments, as the first comment correctly identifies what it is, and then everyone else just ignores that and starts speculating.

———————————————————————

This one looks like a plane spraying stuff. But again it’s rather close to the ground. It’s actually taking off with the assistance of rockets. It’s not spraying, that’s just rocket exhaust.

This particular plane is a Boeing B-47B, rocket assisted take off, April 15, 1954. An no, that’s not a contrail in the sky behind it - it’s rip in the photo. Click on it for a large version.

————————————————————————

This one is used for cloud seeding. It does not actually spray anything but uses silver iodine flares that are either ejected, or burn in place.

It’s operated by the Sandy land Underground Water Conservation district of Plains, Texas, as part of their SOAR program. They have some more photos of similar equipment on their site. They are all small aircraft not capable of getting to the above 30,000 feet where contrails normally form.

—————————————————————————

This next photo is also of silver iodine flares, fixed underneath at large plane.

These also show up in “chemtrail” literature. They are sold by Weather Modification Inc, they make a range of weather modification equipment. About this one they say:

WMI racks for ejectable flares are mounted on the belly of the aircraft fuselage. Each rack holds 102 cartridges. When fired, the pyrotechnic is ignited and ejected from the aircraft. In this configuration, the WMI Lear 35A is equipped with four 102-count racks for ejectable glaciogenic pyrotechnics, a total of 408 flares.

Here’s another, this time from North American Weather Consultants, Inc.

About which they say:

This aircraft-mounted cloud seeding generator is fixed in place, and can burn a silver iodide solution during flight.

————————————————————————–

One of the more pervasive myths regarding “chemtrails” is that current presidential candidate Dennis Kuchinich tried to have them banned by an act of congress, but was pressured by the government to modify the act to remove the mention of “chemtrails”.

So what really happened? In a nutshell, Kucinich did not write the bill (or read it, until too late), the focus of the bill is nothing to do with chemtrails, it was written by UFO enthusiasts trying to:

1. Nullify a vast conspiracy by the “military-industrial complex”
2. Allow the use of suppressed alien technology for free energy
3. Avoid accidentally shooting down (or scaring away) visiting aliens.

They listed a bunch of weird weapons, including mind control, tectonic weapons and (very briefly) chemtrails. The bill was re-written several time in less unusual language to give it chance of passing, but ultimately fizzled in committee. Continue Reading »