Smoke Angel or FSM? Not astronomy! (APOD 22 Aug 06)

[tollwilly125]

... more like Flying Spaghetti Monster!!!

[orin stepanek]

http://antwrp.gsfc.nasa.gov/apod/ap060822.html
Interesting!
Orin

[ben]

This APOD is just a plug for "cool" military technology and has nothing to do with astronomy at all. I know APOD sometimes does clouds but at least those are natural atmospheric phenomena. This is just air pollution intentionally belched out the end of a warplane. If it has anything whatsoever to do with astronomy, I wish the author of the APOD would have explained it. "Ooh a giant owl monster!" just doesn't cut the mustard in my opinion.

[kb7m]

I find it interesting that the C-17 in the picture is not headed away from the flares, but is headed towards them. Some possible explanations are that there is more than one plane and the photo was shot from the one producing the smoke angel and the C-17 shown is following in convoy; or due to the longevity of wingtip vortices (also known as wake turbulence), which can last several minutes, the C-17 shown produced the angel and had time to turn around and "return to the scene of the crime".

[Qev]

*bursts out laughing!* I'm glad I wasn't the only one to see His Noodly Appendage in that image.

Actually, kb7m, I believe the plane is, in fact, closer to the camera than is the smoke cloud: it released the flares while travelling towards the photographer. It's just that the sheer size of the clouds compared to (what is actually a very large) aircraft creates the false impression that the plane is further away.

[Wadsworth]

lol.
True, it doesn't have much to do with astronomy, but it is cool none the less.

[iamlucky13]

I suppose possibly because aeronautics is a major portion of NASA's focus, APOD often has aeronautical or meteorological related pictures. The C-17 dropping flares can be considered in either group because you see aerodynamic effect of wingtip vortices affecting the shape of the cloud and probably condensation of water molecules onto smoke from the flares. Believe it or not, you don't get clouds, and therefore you don't get rain without pollution. You also make it sound like the intent of the flares is to pollute or to create cool patterns. They're decoys for heat seaking missiles. They just happen to look cool.

You may be interested to know that NASA recently did a study into the weather effects of contrails, the vapor trails that form behind airplanes on humid days. Arguably that is relevant, why not this? They've also done pictures related to global warming, which is also pollution-related.

Anyway, I think it's cool and I'm glad they posted it. Regardless, the overall quality of the pictures and the educational tidbits associated with them is more than enough that I'm willing to be disappointed on occasion.

[cbooth]

Yes, it clearly is the Flying Spaghetti Monster in a rare explicit manifestation--er, milanesefestation....

[joseparc]

I must disagree with kb7m and Qev assertions.

It is obvious to me that the C17 is headed away from the smoke angels as I'm sure the photographer can affirm.

[Qev]

Er... hehe, that's actually what I was saying, joseparc. The plane is flying away from the smoke angel, and towards the photographer. I'm pretty sure I can see the cockpit windows, and the faint exhaust trails from the engines are definitely pointing back towards the flare cloud.

[harry]

Hello All


AIRCRAFT-LAUNCHED SMOKE AND FLAME MARKING DEVICES
http://www.ordnance.org/flares.htm

The pattern does indicate the influence of the wing tips.

[ben]

I agree that APOD usually offers high-quality material, so maybe I should have bitten my tongue over this one.

I have no complaint about APOD doing pictures on aeronautic subjects, but as far as I can remember these have featured rockets, the space shuttle, satellites or other technologies that actually have a connection with astronomical science. I don't see the connection here.

As far as it's being "cool," well I won't deny that. But there are a lot of cool things in the world that have nothing to do with astronomy.

As far as pollution being necessary for rain, I'm sure you have a clever explanation for that statement. But I think we all know what "pollution" means in common parlance and I'm pretty sure there was rain on planet Earth for millions of years before our smokestacks and exhaust pipes came along.

[Doggtyred]

As a further aside, the aircraft that is pictured to the right of the smoke formation is likely NOT the aircraft that depoloyed the flares. If you look at the picture you can see the approach lights of the aircraft - these are mounted on the FRONT of the aircraft. When viewed full-size the cockpit windscreen is visible, evidence that the aircraft is on-coming, and has not yet reached the area where the flares were deployed.

It is much more probable that the photographer was onboard the deploying aircraft, and that the deploying aircraft banked left shortly afterwards, which permitted the picture to be taken out of a porthole window in a personnel door.

[Pete]

Nice observation - I hadn't noticed that The Globemaster is clearly approaching the camera.

[ta152h0]

NASA stands for National Aeronautics and Space Administration, a civilian government fund distributer for research projects. therefore a C17, representing the aeronautical arm of NASA, is totally approriate and the smoke dispersion, representing the atmospheric component, how winds visually affect the cloud is also totally appropriate. I do recall seeing a movie of this in the past elsewhere and it is really awesome when put in motion, very similar to a beautiful lady running in the beach sand. Studying the Earth is just as astronomy as studying a black hole location.

[juanroberts]

Not astrological, but it could be more than all that according to prophet Pastafarias:

http://en.wikipedia.org/wiki/Flying_Spaghetti_Monster

[iamlucky13]

The comment about pollution I could've left out, but the basic concept is that water condensation requires something to condense onto...a condensation nuclei. It occurs on dust, but particulate exhaust probably actually assists that. Your comment about pollution and the whiteness of the cloud (indicating it's more water than particulates) brought that to mind. I do agree that the author should've discussed the science revealed by the picture in greater depth.

Regarding the position of the aircraft, looking at the linear perspective, atmospheric perspective (haziness, brightness, etc), and shape of the cloud, I'm not convinced that plane in the picture isn't the one that dropped the flares. I don't know what a C-17's flare capacity is, but each of those "feathers" appears to be left by an individual flare, so it looks like there may be over 50 of them, triggered in two groups, from either two or four banks of flare launchers. They are ejected some distance from the plane, making the overall pattern pretty wide. Furthermore, the whiteness suggests to me that water out of the sky is condensing in the trails of the flares, filling in the empty space with the impressive cloud. On the other hand, in the conditions under which that should happen, you should also see contrails from the C-17's engines...

[Martin]

APOD has never let us down so I suggest that non interested parties bite their tongue.

[waterfeller]

Is it possible that the airplane (Aug 22) is between the cloud and the observer and that a telephoto lens has foreshortened the perspective?

Alternatively, is it possible that the airplane made a 180 degree turn after dropping the flares and is returning to view the cloud? This would place the cloud between the airplane and the observer.

It is hard to know the scale of the cloud.

[Doggtyred]

Furthermore, the whiteness suggests to me that water out of the sky is condensing in the trails of the flares, filling in the empty space with the impressive cloud. On the other hand, in the conditions under which that should happen, you should also see contrails from the C-17's engines...

The whiteness suggests to me smoke from burning white phosporus, the primary component in the anti-aircraft flares in use by the US Air Force. As you said, had this heen a high humidity/saturated atmosphere condition, contrails would have been visible - either from the powerplants or the wingtip vortices

Again, the aircraft visible is unlikely to be the deploying aircraft. If you look at the flare's smoke pattern, you notice that the most disrupted smoke is the furthest from the camera (the "eyes" as formed by wingtip vortices) while the smoke closest to the camera is not yet disrupted from the path that the dispensed flares took. Given the foward motion of the firing aircraft, likely several hundred mph, the smoke pattern would indicate that the path of the deploying aircraft is moving toward and to the left of the line of sight of the camera. This is again in addition to approach lights and cockpit windscreen of the pictured aircraft being visible in enlarged versions of the picture.

[Doggtyred]

Is it possible that the airplane (Aug 22) is between the cloud and the observer and that a telephoto lens has foreshortened the perspective?

Alternatively, is it possible that the airplane made a 180 degree turn after dropping the flares and is returning to view the cloud? This would place the cloud between the airplane and the observer.

It is hard to know the scale of the cloud.

The FAA's airmans information manual, section 7-3-4 Vortex Behavior, with regards to wake turbulence and wingtip vortices trailing aircraft. Paraphrased:

They tend to remain less than 1 wingspan apart, and drift with the wind. They also tend to descend at "several hundred feet per minute" unless within 100-200 feet of the ground. 1000 ft of vertical separation is considered effective/safe, which means that the vortices tend to have de-energized by that point.

That data calibrates the smoke angel eyes/vortices to a size of 170 feet laterally or less (with regards to the C-17 wingspan)

In a non-tactical environment, large transport category aircraft usually turn at a "standard rate" of turn or "half standard rate". Standard rate is 3 degrees a second. 180 degrees would take 1 minute. 360 degrees would take 2 minutes.

Given that the aircraft in view appears to be some distance away and oncoming, it would have to be greater than 2 minutes (had it turned full circle and was coming around again) since it possibly deployed flares. Given that the smoke angel appears well defined, has well defined vortices that are at or slightly below the level of the camera ship, it would be safe to say that not much time has passed since the flare deployment.

The vortices have not descended far below the plane of flight of the camera ship.

I cannot comment on the depth of field argument, with regards to the camera lens, but perhaps the above would address the second possibility mentioned - that asserts the visible plane is the deploying plane, having come around for another pass.

[waterfeller]

Moving the image of the airplane in front of the cloud eliminates the parallax effect makes it much easier for me to see the perspective of the scene. I now believe that the plane is between the cloud and the observer and has not altered course.

http://www.naturalhighs.net/smokeangel_modified.jpg

[BMAONE23]

Nice modification

[iamlucky13]

Ahh...good point about phosphorous. I had thought the flares were magnesium. Also, this quote really seems to go against my theory:

They tend to remain less than 1 wingspan apart, and drift with the wind.

I had figured a zoom lens and the vortices drifting apart were responsible for the wide appearance of the eyes, but if they generally stay together, then a zoom lens shouldn't be able to cause that much change of perspective. Waterfeller...what's it look like if you modify it the other way: move the cloud in front of the plane. The evidence might seem just as condeming that way.

If you look at the flare's smoke pattern, you notice that the most disrupted smoke is the furthest from the camera (the "eyes" as formed by wingtip vortices) while the smoke closest to the camera is not yet disrupted from the path that the dispensed flares took.

I'm not sure if you're referring to the smoke right between the eyes or the trails that go downward from the eyes. It's really hard to tell which portions of the cloud are closest, but the trails that go downward are seperate flares. The C-17 has launchers aimed sideways and launchers aimed almost straight down. Check out this picture.

[BMAONE23]

Anyone have an MPEG file of a smoke angel being formed?

Here is another good pic
http://www.galleryoffluidmechanics.com/ ... mc130b.jpg