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Contrails, Dark Lines, Black Beams, & “Chemtrails”

People who think persistent contrails indicate some kind of conspiracy (which they call “chemtrails”), sometimes 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” or “black beams” are simply various kinds of shadows. There are actually three main kinds of dark line related to contrails.

1. Self Shadow

Where the contrail itself is in shadow and appears dark. This can happen in 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, such as parts of the contrail above.

2. 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.

There’s nothing new about such shadows. Here’s some from 1955:

One interesting thing about these shadows is that it frequently looks like the contrail is below the clouds when it’s actually above them.  You can see this illusion in the photo above. The reason this happens is that the white of the thin layer of clouds and the contrail are additively transparent, so they look identical, regardless of which one is in front of the other. The illusion happens because the brain interprets the bluer regions of the cloud as being darker regions in the same plane as the cloud when they are actually holes in the cloud. The contrail will seem solid white when viewed through the holes, or when it is in front of the holes.

3. Edge Shadow (Volumetric 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 above image is an excellent demonstrating of the fleeting nature of these edge shadows.  Two photos were taken just a few minutes apart, in the first the camera is more fully in line with the plane of the contrail.  In the second the contrail (or the photographer) has moved, and we are viewing the edge shadows from a slight angle which reveals they are made up of two or three segments, caused either by the plane turning slightly, or variations in upper-level winds bending the contrail.

Most photos of these odd shadows don’t include the sun.  But when they do, you’ll see that the sun is lined up with the contrail (or part of it)

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.

The image above is another great illustration. There are multiple contrails, but only the one that intersects the sun creates the edge shadow. Photo from “Col” on usenet uk.sci.weather.

[UPDATE] This video I shot in my kitchen gives an excellent illustration of these types of shadow.

[Math Warning] It’s a bit difficult to explain these edge shadows (also called volumetric 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 endpoints 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 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.

[Update] I found a useful video of a contrail edge shadow (or “volumetric” shadow, described above):


It’s all in one shot, which is great, as you can see how the various misinterpretations can arise. It starts out with a shot of a black line across the sky, with no visible reason for it being there. The sun is obscured by the house on the right.

The cameraman then zooms in in the dark line, and we see a contrail being formed along it. It looks like the plane is following the dark line, or somehow projecting a beam of dark energy in front of it!

Then the cameraman walks around the house, and we see the source of the dark line – the contrail is EXACTLY lined up with the setting sun, and is simply casting a volumetric shadow which the cameraman is lined up with. The shadow is accented as the suns rays are nearly parallel to the contrail. Here I’ve stitched some frames together so you can see this. I encourage you to examine the video to confirm this.

[Update 2]  Check out this video of the Space Shuttle launch, a dark shadow forms in the last 30 seconds:


[Update 3] Crepuscular rays are parallel, but usually don’t look it. This is partly why the contrail edge shadows are not recognized as the same type of thing.

Crepuscular rays are parallel!

view of crepuscular rays from space:

230 thoughts on “Contrails, Dark Lines, Black Beams, & “Chemtrails”

  1. Strawman says:

    This site doesn’t pretend to have credentials, it merely checks the chemtrailers’ claims for factual value. So far, there’s none to be found.

    So, just because people find something strange, doesn’t mean there on to something.

  2. I did fund this one experiment to demonstrate that volumetric shadows are only visible when viewed edge on.


  3. MikeC says:

    I think a better idea than assuming people “dont’ know shit” is to look at the actual information presented.

    If I say 1+1=2 then me not being a mathematician doesn’t mean I’m wrong. Similarly there’s a lot of science around about the atmosphere which is reported on here – it isn’t the people on here who have done the research – so there’s no point complaining about the “lack of credentials” on here as a reason not to read and try to understand the research.

    Relying solely upon someone’s credentials to validate their ideas is a fallacy known as “credentialism” – if something is correct then it is correct regardless of who says it, and ditto something is wrong regardless of who says it.

  4. Stupid says:

    although a lot of relying on any credentials or evidence, makes you a believer….and less of a know-er.
    It makes you a “what if-‘er”

  5. Jason says:

    I saw this line a few days ago. But it seemed as if the jet start flying crooked after the shadow cast and then the jet disappeared! What happened then?

  6. It was probably no longer leaving a contrail (as it moved into a different region of air). When planes stop leaving contrails, they can be little more than specks in the sky and hard to keep track of.

  7. Your Mom says:

    I don’t understand how chemtrails are still dismissed as conspiracy when there are multiple pictures of the inside of planes that are filled with just CHEMICALS and are hooked up to be sprayed in the atmosphere.

    These lines are not just “shadows”. I watched one the other night directly infront of a massive unmarked airplane which was spraying the chemicals into the sky. It even moved along with him.

    You are a very sad and mislead human being if you do not believe this is happening.
    Look up.

    Those are NOT contrails. Nor are those black lines, “shadows”.

  8. Your Mom says:

    Even the pictures posted above are NOT contrails. How can you think they are?
    There are planes that DON’T even leave a trail behind them… That’s how it should be.

    Chemtrails are very real, along with the diseases it creates.

  9. Jay Reynolds says:

    Hi, Mom. I know Mom’s are always right, but this time you are so wrong.
    Mom wrote: “I don’t understand how chemtrails are still dismissed as conspiracy when there are multiple pictures of the inside of planes that are filled with just CHEMICALS and are hooked up to be sprayed in the atmosphere.”

    Sorry, Mom. Those photos have been debunked already:

    If you have any new ones which haven’t been debunked already, let us know at the link above!

    Mom also wrote:”Even the pictures posted above are NOT contrails. How can you think they are?
    There are planes that DON’T even leave a trail behind them… That’s how it should be.”

    Mom, that’s been debunked already too:

    Mom, don’ be angry at anyone here for letting you know that someone has made you believe in bunk.
    Get angry at whoever “set you up” by telling you that bunk in the first place!


  10. Invisible says:

    I think that the best way to resolve these issues, whatever they may be, is to work together and allow room for our hypotheses to change. Attacking each other’s characters and the “ridiculousness” of their claims helps nobody; and no, a personal ego-boost doesn’t count as helping! 🙂

    If there are chemical trails being intentionally sprayed above many countries of the world, how can we test for them on our own and reveal who is responsible? I have seen some individuals 1) testing (for aluminum, barium, other heavy metals, and some microbials) rain water collected on clear days versus heavy-trailing days (in some sort of uncontaminated collection saucer) and 2) using high magnification lenses to collect plane information and track this data.

    I have to admit that I was a bit uneasy seeing a black line in the skies on my drive into town today. I took a photo and later analyzed it to find that it could potentially be a shadow. But, that is not to say that I am convinced there are not chem-trails being sprayed.

    And, if there is no real agenda for spraying millions of innocent people, why are so many people reporting them and raising concern? I cannot believe that the David Ickes of the world have seeded this conspiracy theory about chemtrails just to sell their books. People are genuinely concerned and deserve respect in addressing these issues. Afterall, psychosomatic illness is real and scientifically proven…Even if it is all a hoax, it is harmful just for people to believe they are being poisoned. However, the general person is no scientist and may have a little trouble devising ways to do further research on their own.

    An interesting links that I have found lately include one of a geo-engineering conference in which scientists reveal their desire to spray aluminum (barium and strontium are also desirable) into the atmosphere to begin addressing greenhouse gas issues. Alongside that link, it was reported that the US Dept. of Agriculture has plans to spray 10-20 megatons of aluminum. The video is revealing, but it may also have been cut to be bias and put his words into the worst possible context…not that there could be a good context for talking about spraying huge quantities in our atmosphere without understanding, fully, the risks involved.


    Not to mention, the government and private companies have been working seriously on weather modification for some time. Global warming issues have a lot of money behind them…in marketing as well as research and sales of various products. This could be a potential explanation:

    http://presscore.ca/2011/?p=2261 (talk a little about weather modification via the High Frequency Active Auroral Research Program in the US; funny thing…HAARP’s website did used to have more information that discussed the “exciting prospect” of weather modification. It does, in fact, appear that this information has been removed…how inconvenient for my case!)

    To both sides, please be open minded. Let’s work together. Quit insulting people because you think that they are stupid…who are you?! We are in this together. Let’s get this figured out…one way or another. And, it seems a good idea to remember that this is an international community. What we see in the US may not be seen so much in other countries and vice versa. Perhaps this can be a platform for those conducting further research to learn a little about what is being seen elsewhere…with caution that some people may or may not be intentionally deceptive.

    Much love!

  11. Jay Reynolds says:

    Invisible, I watched the scientist in your video, but he does not say he has a desire to do geoengineering. He has repeatedly said he does not want to do geoengineering, he says it would be dangerous, and he does want to discuss the means whereby it could be done if it were ever needed. He also never says anything about barium or strontium, neither of which would have any usefulness for geoengineering. At the link, it does not say the USDA has plans to spray anything, indeed they do not have any such plans.

    I really don’t see how you got any of these ideas, none of what you say has ever been stated either by David Keith or the USDA. You seem to have read and heard things that were neither said nor written.
    Don’t know why you would do that, but you are not correct in any way whatsoever.

  12. this is definitely chemical trails please look up on youtube why in the world are they spraying . It will explain everything

  13. You tube ” why in the world are they spraying” … you have nothing to loose, only knowledge to gain

  14. Jay Reynolds says:

    “Why in the World Are They Spraying” simply repeats the same errors made and debunked in Michael J. Murphy’s first movie.

    The strangest thing is that Murph had been made fully aware of all the above errors long before e put out his second movie. What do you call someone who knows he is wrong, but continues telling the same false stories to people anyway?

  15. Rude Bastard says:

    That video is nothing but lies. Every single claim in it has been easily refuted, or pointed out that evidence to support the Claus doesn’t exist.

    Oh, bye the way, the word is “lose”.

    Just because people make videos of contrails and called them “chemtrails”, doesn’t mean they should.

  16. Rude Bastard says:

    Jay, the answer to your question is “chronic liar”.

  17. Rude Bastard says:

    Damn auto correct..

    “Claus” should have been “claim”

  18. Raphaelle says:

    UNCINUS, what a great job you have done of keeping the disinfo on chemtrails going… all these years too. Relentlessly, and oh so patiently… tell me, exactly how much are they paying you? Must be a good living to keep fighting for so long and maintaining your good humor. Of course, nothing can sway you, from your task of giving credibility to the excuses to the world wide web of lies we are being fed by our beloved dark shadow of a government. And your scientific mumbo jumbo, sounds so good it can explain away COMMON SENSE, with BIG WORDS no one can argue against, and if someone gives you an eye witness example trumping your answers, what do you do? Why, you just shoot him down as not knowing what he/she was looking at…BRAVO!!! Therein lies the making of one TREMENDOUS disinfo shill… you must have a nice house from all your hard and dedicated work… WELL EARNED! Below is just ONE example I have chosen to illustrate this fine job of SQUELCHING an individuals excellent and intelligent eye witness testimony, that can be found on this EXCELLENT DISINFO SITE:

    S says:
    January 29, 2009 at 1:40 pm
    I’ve been following the chemtrail contrail discussion for about 2 years now. Over that time I have seen an increase in the amount of lines in the sky and take account of what the weather was like, when they occur, and how many times that day. There are specific places I travel to around the continental US a few times each year, and each time I return there has been an obvious progression in these lines at these places. I notice less lines in top states such as Minnesota and North Dakota. In Virginia and North Carolina they were daily, sporadic and moderate. In Wisconsin and Iowa I actually have made a fanfare out of watching the sky because there are so many.
    For a 2 week period in Wisconsin, a place I have visited frequently for 9 years, I would sit outside for 2 hours each late morning and on the dot, two small planes would appear and go in opposite directions releasing trails. Then they would fly back to the beginning position and continue again after each line had dissipated, repeating these exact coordinated positions in the sky as if tracing the old line. This would continue for 45 minutes, then the directions would change with the same duration of time. These lines especially caught my interest because it was a scheduled occurrence. The planes were low enough for me to see the parts so identifying them as the same from previous days was possible. After 4 days I was smiling shaking my head. I am well aware of all of the possibilities and reasons as to why these lines exist and what their purpose is. My own opinion is not really necessary here, I wanted to identify my visual facts. I smiled because I said to myself, “great, what am I exposed to now?!” It was blatantly obvious that these planes were to be in this specific position at that time repeating for so long. Airplanes do not make a point of repeating the exact traceable path or a perfect grid blanketing a specific geographic location. Perfect grid. Like my old math tablet.
    I don’t know the answers and I will not get carried away with assumptions, but I am a proactive being aware of their surroundings.
    Don’t let yourself become distracted.

    Uncinus (Mick) says:
    January 29, 2009 at 10:25 pm
    It seems that what your were seeing were simply scheduled commuter flights flying overhead at their regular times. That’s why they show up at the same time each day. They were not the same planes flying back and forth, but rather multiple planes flying overhead from airports far away.

  19. Raphaelle says:

    In short, he said “THEN THE DIRECTION WOULD CHANGE” and you assumed he meant then the planes disappeared and other planes came into view, indicating commuter flights… Did you run out of science, my friend? Don’t bother answering, as your words have no value. Your normalcy bias, will not let you receive the information that proves you are full of bull. There are too many examples I could site after studying your site. What a waste of mine and other’s time. We are trying to save the world from its deadly ignorance, while you try to claim exclusive rights to understanding the skies cause you have a degree. Men have been studying the skies since the beginning of time, and now YOU want to tell us we can’t possibly understand it without a degree?? F*** you, we are humanity, and we are not going away, and neither is our confidence in what we are seeing, nor our trusting our eyes. You remind me of a joke Eddie Murphy says when caught cheating, by his girlfriend “Who are you going to believe, me or your lying eyes?” lol.

  20. Rude Bastard says:


    That was a hilarious rant. Thanks for the laughs.

  21. now YOU want to tell us we can’t possibly understand it without a degree??

    Not at all! I think you CAN understand it without a degree, and that’s partly what I try to do here – make the science accessible.

    My degree is in Computer Science, and it not at all relevant to Meteorology, but I can still look thing up, and I can still explain thing to people, and discuss what they see in the sky.

    There are a number of explanations for planes seeming to go back and forth. I think most of the time (based on what I see here, and normal air traffic) it’s different planes.

    Occasionally though planes will fly back and forth, and to U-turns, for a variety of reasons. I’ve seen this myself. See:

  22. Sarah says:

    Great to see a site showing the increase in POLLUTION happening in our skies. There are definitely more particles in the air and this is absolutely in connection with the aircraft if you take the time to look at them and what they are leaving behind. It’s been a while since I have heard of an airline going out of business, how are they making money when fuel is going up in price all the time?

  23. Jay Reynolds says:

    Sarah, I can speak to your comments. The actual facts are that atmospheric particles have decreased over the time period of the chemtrail hoax. see:

    The leadersip of the chemtrails ‘movement’ have known these facts for quite some time. They just haven’t decided to tell you. Very bad thing to do, to send someone like you out in public without this knowledge when they knew about it already. You should demand that they address his issue, because until all of you do, there can be no progress and folks like you will show up here only to find you have been deceived.

  24. eduardo says:

    hey mic how much dohtey pay it for making people pass by stupid’ how do you feel now that the all world is being fumigated? you and ass holes like you will be accountable for whas is happening…if you have childrens, or family remeber you are one of the responsibles…

  25. I don’t get paid. This is just a hobby.

    Can you point to one thing that I got wrong on this site? I’d be happy to fix it.

  26. Knife says:

    No one knows but i believe they use the contrails to shadow the pathway of another ‘unknown vehicle’
    Either that or we are breathing in a gel like substance which will take 30years of our life expectancy.

  27. Jay Reynolds says:

    If “no one knows”, who WOULD know?
    Riddler, is that you?

  28. Strawman says:

    So, we have 30 years of our life expectancy taken from us and life expectancy is growing every year. I can expect to reach 80 or more, even though 30 years have been taken from me?

    Ok with me. 80 seems quite enough.

  29. captfitch says:

    Yes- thier plan is to draw attention upward with massive white lines so no one can see a tiny craft. brilliant

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