Kablam!

By Phil Plait | September 2, 2010 7:00 am

This image is stunning. And not just because, well, it’s all explodey and stuff:

tomahawk_test_3panel

[Click to explodenate.]

The three panels show a 1986 test of a Tomahawk cruise missile. The missile traveled 640 km (400 mile) low over the terrain to detonate above the target, a decommissioned fighter plane. It’s pretty clear the test was a success.

But what caught my eye immediately was the middle panel. Let me zoom it for you:

tomahawk_testblast

[Click to hugely embiggen!]

[Note: added noon PDT Friday: There's a lot of discussion in the comments below on both the veracity of this test and my interpretation. I've been on travel the past couple of days, finishing up some Bad Universe stuff, so I haven't been able to look into this. So I admit I might be wrong, but won't know one way or another until I can sit and look into this. Stay Tuned.]

Now look carefully there. When the missile exploded, the expanding debris cloud from the vaporized weapon was probably moving faster than the speed of sound. Even so, in this second picture you can see none of it had touched the plane yet when the shot was snapped.

tomahawk_test_obliqueYet look at the plane: it’s on fire. How can that be?

It’s because of something that moves much faster even than supersonic debris: light. When the warhead exploded, it sent out a huge pulse of heat in the form of infrared photons, light that travels about a million times faster than sound. As far as that flash of heat was concerned, the expanding debris was standing perfectly still! There was plenty of time for that heat to get to the plane and set it aflame before the explosion itself could reach that far.

Note that third picture, taken from an oblique angle. You can match the features in the fireball to the ones in the second picture. The ground around the plane is lit up by the blast, and again no debris had yet reached the plane itself.

It’s a little counterintuitive that the explosion works this way. We think of explosions as being made of expanding stuff, but it turns out that light has its role to fill as well. In fact, this is important in other ways: one idea to push Earth-crossing asteroids out of the way is to light off a nuke nearby. The force of the explosion itself isn’t all that great in space, because there’s no air to create a shock wave. The only momentum you give the rock directly is the expanding debris from the bomb itself, which isn’t all that much. But the blast of heat/light is immense, and can heat the asteroid past its vaporization point. The flash-vaporized rock expands, pushing on the asteroid like a rocket motor.

Unfortunately, modeling of this shows it doesn’t work terribly well compared to other methods (like simply slamming the asteroid with a space probe like a linebacker hitting a quarterback). Still, you need to consider all the details when thinking about things like this. The devil hides in them, y’know!

Oh, and one more thing. This Tomahawk test was done 24 years ago. How much has the technology improved since then?

Yikes.

MORE ABOUT: Tomahawk missile

Comments (96)

Links to this Post

  1. ¡Badaboom! | September 2, 2010
  2. The awesome aircrafts thread | September 2, 2010
  3. Michael Alan Miller » Right to bear cruise missiles | September 3, 2010
  4. Tomahawk » FNQhome.com | September 3, 2010
  5. 3 for 1:Vocab builder plus cool photo and military info - INGunOwners | September 3, 2010
  6. Bigmouth & Bedbugs : BLig | September 3, 2010
  7. Kablam! - Benny Ling’s Bling | September 5, 2010
  1. A good conspiracy theorist would have come up with an entirely different and unscientific scenario. This entirely proves your lack of talent in conspiracy theories.

  2. Coda

    In the words of you, “Holy Haleakala!” :)

  3. JoDaWi

    Wowzers; that center pic is frakkin awesome!

  4. Messier Tidy Upper

    WWWWHHHOOOOOOOOOO-AAAAAAHHHHHH!!!! [Picks up jaw from floor.] 8)

    Stunning images. That’s got to be one of the most spectacular images posted here yet – which is saying a lot! :-D

    [Pedant mode on.]

    Yet look at the plane: it’s on fire. How can that be?
    It’s because of something that moves much faster even than supersonic debris: light.

    Minor nitpick but don’t you mean *heat* or more specifically photons at infrared wavelengths instead of light? Would there be any accelerated to ultra-violent /X-ray and other electromagnetic spectrum wavelengths emitted by this sort of explosion too? Or would it NOT be energetic enough?

    [/Pedant mode off - goes back to gazing at awesome piccies.]

  5. kevbo

    Did you just say the Devil hides in the details of Science?

    I certainly hope this blog is not read in Kansas. Or Texas. Or Dover, PA. Or…

    and @4, I believe that Phil is using ‘light’ in its more general astronomical meaning, as in electromagnetic radiation, which includes heat, visible light, X-rays, T-Rays (yay SGU), etc.

  6. This Tomahawk test was done 24 years ago. How much has the technology improved since then?

    “Improved” being a word that, in this case, is open to interpretation.

  7. Tomahawk Missile Variants

    Watch “Tomahawk Missile Variants” at http://www.youtube.com/watch?v=19XXTArAGaM and pay close attention to the “TLAM I C Programmed Warhead Detonation” part starting at about 1 minute and 12 seconds into the video.

    And here’s the URL for those spectacular “Kablam!” photos: http://chamorrobible.org/gpw/gpw-20050304.htm

  8. Dave Gannon

    Hi Phil, another excellent photo! However, whilst I don’t doubt that the ir or heat hitting the plane first could have caused it to ignite, if you look closely (I do mean closely!) at the larger head-on image you can make out “stuff” flying out of the explosion beyond the fireball. The “stuff” clearly looks like it has already impacted the plane and in some cases you can trace the paths through the plane.

    I super-sharpened the image in photoshop to make the streaks clearer and uploaded it to picasa. http://picasaweb.google.co.uk/100738947888918116206/PlaneExplosionSharpened?feat=email#

    I hope that link works; I’ve never used picasa before.

  9. Zippy the Pinhead

    That’s what happens when the EYE OF SAURON gets you.

  10. My 11-year-old daughter saw the images, and I was explaining them to her. The discussion took a few turns along the way, and ended with how the Moon is receding from the Earth. While looking up the information, I came across a Creationist website that “explains” how a receding Moon is evidence for a young Earth.

    (URL mangled, to prevent linking to it.)

    creationwiki dot org / Moon_recession

  11. Messier Tidy Upper:

    Minor nitpick but don’t you mean *heat* or more specifically photons at infrared wavelengths instead of light?

    <DoublePedant>

    Well light does travel faster than sound. :-)

    And, isn’t infrared radiation just light outside the visible spectrum? (Same with ultraviolet.)

    My nit… I don’t think many people (if any) would call x-rays and radio waves “light”. So, where does the “light” part of the electromagnetic spectrum start and end?

    </DoublePedant>

  12. smelly hamster

    Whoa – hang on. I’m not sure you’ve done your homework on this one Phil… if this were true it would imply that the Millenium Falcon would not have made it out of the Death Star at the end of Return of the Jedi.

  13. Physicalist

    That can’t be right. After all, any competent action hero would be able to see that explosion and still have plenty of time to outrun it.

  14. Rick W.

    Clearly, if you look at the second picture, this whole thing was faked by the U.S. Government to cover up UFOs on Mars. There are two main explosions on the jet, one over each wing. Everyone knows that the wings are where the feul tanks are located. I have heard from unnamed (and nonexistant) sources that remote control bombs were set to go off at the exact second the cruise missile, if indeed it was a cruise missile, exploded. Give the military credit, they found a soldier that could push the button for the bombs on the plane at the exact sedon the missile exploded.

    Okay, I don’t know how Hoagland and the others do it. I just gave myself an aneurysm. I got to go to the emergency room now.

  15. rob

    xrays, UV, infrared, light, etc are all electromagnetic radiation.

    i suppose you could call them all “light” but typically “light” refers to visible light–what you can normally see with your human eyes. the wavelength range for that is about 400nm to 800nm. the UV part of the spectrum starts just under 400nm and the infrared starts just above 800nm.

    note, however, elves and orcs are supposed to be able to see in the infrared, so their vision likely extends up over 1000nm, perhaps to 1200nm.

  16. G Williams

    “Unfortunately, modeling of this shows it doesn’t work terribly well compared to other methods (like simply slamming the asteroid with a space probe like a linebacker hitting a quarterback)”

    The difference is, we have a lot of nukes, but not a lot of line-backer-esque space-probes, so it might be more plausible to just launch several nukes we already have handy at an asteroid than to build and launch a space-probe.

  17. Pete Jackson

    Is it possible that the plane and surrounding ground was covered in some kind of accelerant such as gasoline in order to make this dramatic effect? Note that the ground is burning too, even under the plane, with no sign of any shadow from the plane. Further note that bushes further away from the plane are not burning, and there seem to be only a few of them, not enough to form the continuous sheet of flame right under the plane. In addition, I would have thought that airplane surfaces were mainly bare metal which would glow under extreme EM radiation, but would not burst into flame (although a painted surface might well burst into flame).

    I recall pictures of houses sitting under where nukes were detonated in the Nevada desert in the post WWII atomic tests. The intense radiation from the nuke would make the house smoke intensely, but not burst into flame before the shock wave, arriving seconds later, would blow the house to smithereens.

    So, color me skeptical…

  18. Gus Snarp

    @Ken B – I’m with you, heat is nothing more than infrared light. Phil’s terminology is dead right. I suppose one could say the cut off for “light” is at the visible, but visible to whom? If animals can see it but we can’t, is it light? If we can form images with it using electronics is it light? Seems pretty hard to cut it off. And if we are speaking of the “speed of light” then we ought to recognize that all electromagnetic radiation is light. Otherwise we need to start calling it the speed of electromagnetic radiation. Or just 299,792.458 kilometers (@186,000 miles) per second.

  19. Nemesis

    @#4

    You have to read past the part you’re trying to tidy up. See:

    “When the warhead exploded, it sent out a huge pulse of heat in the form of infrared photons, light that travels about a million times faster than sound.”

    I’m not sure the guy with the PhD needs help with introductory physics.

    Besides, I think the plane was rigged with c4 and a remote detonator. I’d bet if you look at the government’s top-secret files, you’d find a photograph of the plane burning before the missile detonated.

    Actually, it was probably ghosts or evil spirits.

  20. Gus Snarp

    @Pete Jackson – Magnesium is commonly used in military aircraft fuselages, so I wonder if that is the case with this plane. Magnesium is highly flammable, and the intense, almost white light from the burning plane could be magnesium. That might explain why the plane so readily burst into flame from the heat.

  21. #8 Ken B

    That site made my eyes hurt. It is sad that theists will go to such lengths to lie in order to support their religion. What is sadder is that many people will look at that article and assign it totally undeserved credibility simply because it looks “official” and “sciencey” to the naive.

  22. Brent

    Physicists regularly refer to any electromagnetic radiation as “light” and will say “visible light” to make it clear that, for example, a piece of instrumentation is intended to be used for light in the visible spectrum. How specific you need to be is a matter of context.

    Infrared light can transfer heat but infrared light is not heat!

  23. dlm

    I’m not sure this is due to IR from the explosion; I’m not sure there is enough IR to start a fire at that distance.

    More likely it is due to the shock wave from the blast. That moves out at supersonic speeds and is ahead of the debris field from the explosion. The shock wave would shatter the fuel tanks (typically in the wings) of the aircraft and should have sufficient energy to ignite the fuel. That would also explain the fire along the ground around the aircraft.

  24. Jim Ernst

    I see 4 different pictures. The three in the combo (Before, Early, Late), and one separate, at a different angle.

    I take it that the fourth image is from a different source, but is of the same test, a very short time before the second one? It appears to show the intense light just before causing the plane to burst into flames.

    This may be a dumb question, but….
    If that is the case, what is the speed of fire? Not how fast can it traverse along a fuel source, but how quickly a flame can travel from an ignition point, straight up. It certainly appears to be faster than the debris.

  25. The technology has improved drastically.

    Shaped charges give a cone shaped blast instead of a round fireball, high explosives have been engineered to give of more “light” in the desired spectrum to do this kind of damage, and the whole process is further along the “surgical” method.

    In some cases it’s gotten too good. Look up what happened when the Air Force first hung a missile off a predator drone. The Hellfire was designed to blow up tanks. The shaped charges in the missile were designed to blast through inches of reactive armor and steel. The missile itself relies almost entirely on the effect Phil shows us in the picture above, there is very little “stuff” in the missile to do damage, it’s almost all from the chemical/”light” reaction.

    So it didn’t work so well against “soft” targets. The Army (who designed the Hellfire) had to add a collar around the missile deigned to fragment into shrapnel because the missile would blast straight through a SUV or other “soft” target, and the bad guys would run away after. Dazed, scorched and with messy pants, but still run away.

    So this collar, a simple curved metal band pre-etched with shrapnel lines, was added so the explosion had more “stuff” to expand in all directions. Worked really well too. After that, SUV’s stopped being recognizable as vehicles.

    I believe it was USAF General Jumper that was behind that… I know 20/20 did a story on it a few years back. My only point is that explosions today are as much about directed energy as lazars or beam weapons.

  26. Messier Tidy Upper

    @12. rob Says:

    note, however, elves and orcs are supposed to be able to see in the infrared, so their vision likely extends up over 1000nm, perhaps to 1200nm.

    Not dwarfs & goblins? Or hobbits for that matter? As the fantasy underground I’d have thought infra-red vision would be handy for them too! ;-)

    @16. Nemesis :

    @#4.You have to read past the part you’re trying to tidy up. See:
    “When the warhead exploded, it sent out a huge pulse of heat in the form of infrared photons, light that travels about a million times faster than sound.”
    I’m not sure the guy with the PhD needs help with introductory physics.

    One of the things I like about the Bad Astronomer is that he’s willing to admit when he’s wrong – on the rare occassions he is – and is usually happy to be corrected. (Even the smartest people slip up occassionally.) Wish more folks were like him! ;-)

    I see what your saying but he still calls it “light” there. ;-)

    “Heat”, “Radiation” or “electromagnetic radiation” or just leaving it at “photons” would be more technically accurate methinks. Yeah, I’m being a pedant I know.

    PS. Interesting that nobody ever says “the speed of heat travels faster than sound” which is as accurate as saying light does – or is it?

  27. Chris A.

    For those taking Phil to task for his use of light as a synonym for “electromagnetic radiation,” you don’t hear people referring to “the speed of x-rays,” or “the speed of ultraviolet photons,” etc., right? And yet it’s understood that when we refer to “the speed of light” that encompasses the entire spectrum. Since the speed of the IR photons was the crux of the biscuit here, it’s appropriate to refer to them, in this context, as “light.”

  28. Skinny Dennis

    I think what caught fire on the plane was paint. If you enlarge the 1st photo you can see black and maybe yellow on the wings. The flash point probably isn’t all that high.

  29. @ All:

    Be careful of your conspiracy theories. The Tomahawk is still in use, and your house might be the next testing ground. You’ll find out first hand whether the pictures were faked or not.

    Re: Light vs. electromagnetic radiation

    My thinking is there’s a reason it’s called the “visible light spectrum”. If they have to clarify that the light our eyes picks up is within the visible range, then that must mean there is light that we can’t see.

  30. Matthew

    Is it just me, or does anyone else see the smiley face in the middle of photo #2? : )

  31. Kne

    Many physicists, myself included, often use “light” to refer to *any* frequency of electromagnetic radiation. It’s all the same phenomena, whether human eyeballs can see it or not. Just like sound waves are called sound waves even if they’re not in the audible range.

    On the rare occasions when a physicist cares about whether EM radiation can be detected by a human eyeball, we’ll say “visible light”.

    My 0.02.

  32. Floyd

    My long-deceased father worked on some part of the Tomahawk missile, maybe the target sensor, back in the 60s. Seems to work just fine.

  33. MT-LA

    Re: Light vs. Heat. I think we’re being a little too loose with the definitions here. Visible light can make something hotter, but visible light is not interchangeable with heat. Heat (if I remember correctly) is a thermodynamic measurement related to the oscillation of atoms. Photons can impart heat by impinging on a surface and thus exciting the oscillation of the surface’s atoms. But I don’t think that the photon itself has heat associated with it (true or not true? any physicists in the audience?)
    Also, a hot surface will radiate in the electromagnetic spectrum, but it is not giving off “heat”. It is radiating photons as a result of electrons dropping in energy states.

    Consider the other two forms of heat transfer: conduction and convection. Neither of these forms have anything to do with the electromagnetic spectrum, and yet they clearly pass heat from one substance to another. If light and heat are indeed interchangeable terms, then you would expect that the defining equations of all three forms of heat transfer would involve the frequency and amplitude of the photons involved (which they dont).

    In summation, I think Phil nailed it by saying “a huge pulse of heat in the *form* of infrared photons.” Clearly, there was not enough time elapsed for the heat to travel through convection.

  34. JerryP

    One other point… the fighter plane seems to be surrounded on 3 sides by berms, presumably to act as a shield, but also having the effect of concentrating the blast radiation into the target.

    Any physics whizzes here agree on the point that the blast would be more spread out, and perhaps the plane wouldn’t have suffered such extreme damage?

    Either way, I wouldn’t want to test that thought by standing under it. Just sayin…

  35. jfb

    @Pete Jackson

    Note that the ground is burning too, even under the plane, with no sign of any shadow from the plane.

    There probably was, but either that was a couple of frames earlier or it was too short-lived to be captured on a frame of film. By these frames the underside of the plane is clearly burning, so there wouldn’t be any shadow anymore.

    Further note that bushes further away from the plane are not burning, and there seem to be only a few of them, not enough to form the continuous sheet of flame right under the plane.

    Remember that the intensity of light drops off as the square of the distance; anything more than a few meters away doesn’t get enough radiation to flash over immediately, although I’m certain you would find some scorch marks if you looked.

  36. Mike O

    I remember seeing this years ago. This was a test performed on San Clemente Island off the So. Cal. coast. Here is a link to the video. http://www.youtube.com/watch?v=19XXTArAGaM

  37. Ken (a different Ken)

    OK, I have to disagree with the fundamental interpretations of the pictures. And no, conspiracies need not apply. :-)

    Where, exactly, are you seeing the front of the debris cloud? The smoke surrounding the fireball? I don’t think so.

    Go look at any Mythbusters episode, or whats-its-name that new astronomy show. When an explosion is set off the fireball and smoke very quickly expands to a certain radius, then drastically slows down. The shock wave continues at the same speed past the edges of the ball, along with a rich assortment of hot shrapnel – the shrapnel being a key part of nearly every warhead and the part that does the majority of the damage.

    Assuredly for this test the plane was filled with fuel. It can be argued that it’s a realistic scenario, since nobody keeps aircraft with empty tanks on the ready line. I think in the second panel we’ve seen the fireball grow more or less as big as it was going to, and the hot shrapnel from the explosion has already made swiss cheese of the aircraft wings and fuselage. Fuel will immediately splash and ignite. Hence not only the glow and flames on the plane, but also the areas on the ground. A short time after that initial hit, the flames get to the bigger areas of the fuel tanks (e.g. fuselage tanks) and bang, you get pic #3.

  38. What surprises me about the whole thing is that it actually caught fire (with real flames and everything) before the debris from the cruise missile obscured the area. I guess I just never thought that the “speed of flame” was anywhere near that fast (I mean, we’re talking fractions of a second here). Although that fourth image in the article with the plane appearing superheated is pretty awesome.
    To the point raised by @Pete Jackson (14), I don’t think the view we’re seeing allows us to really identify “under the plane”. The area you’re referring to may actually be behind or in front of the plane’s wing and just appears to be under it because of the perspective. Still, it’s pretty amazing overall.
    Thanks Phil!

  39. Georg

    If this infrared ignition is true (I am still a little bit sceptic)
    the load of the tomahawk is not “normal” explosive.
    In that case the load will contain a lot of metal (aluminium?) powder
    and some oxidant. (similar to the oldfashioned powder used
    in fotography hundred years ago)
    Georg

  40. Wayne Conrad

    There are two definitions of light in play. The common definition is electromagnetic radiation you can see with your eyes. The physics definition is electromagnetic radiation of any wavelength. Phil used the physics definition. A scientist used a word according to its scientific definition. So… what’s the big deal?

  41. Phil, that is incredible. That’s for showing the image of the plane on fire before the debris gets there. Pretty cool!

  42. Elmar_M

    I saw this awesome picture in a popular science magazine almost 30 years ago. Thats how old that is :)
    Thats how old I am… sigh..
    Anyway, saw it back then. So sorry to say that Phil, it is not new. Your post was still very educational though :)

  43. Stefano

    none of it had touched the planet

    an Astronomer’s Freudian slip

  44. Georg

    none of it had touched the planet

    Is the atmosphere a part of a planet?
    Georg

  45. Dr. Demento

    • #14 & 29 – I’ve actually attended “Live Fire Test and Evaluations” – there is absolutely no fuel or accelerant present in these test. The last thing the folks who run these tests wants is to be responsible for starting a raging, out of control fire. The fire they do create can be problematic enough.
    • #14 – these tests are held in remote and desolate areas – sparse vegetation, open areas, unpopulated. Your contention that the flames in these pictures do not form a continuous sheet on the ground (although your assessment of that is up for interpretation) is reasonable given the testing area conditions.
    • As for why the bushes in the background aren’t burning – infrared is a low energy particle, which dissipates energy quickly. Obviously, there was sufficient energy from the explosion to ignite things in the immediate vicinity, but the energy rapidly dissipates as distance increases
    • Planes are not bare metal – they’re painted to camouflage them in the sky. Otherwise, a big, shiny object has no stealth ability at all! Also, the “glowing metal” is simply due to the metal being heated – most metals have no inherent phosphorescent ability.
    • The nuclear tests – the movies/houses you’ve seen are taken at quite a distance, close enough for shock wave to affect, far enough the heat/radiation doesn’t. Otherwise, the camera would catch on fire too, and where would the pictures come from?
    • #15, 19-20 – Heat is most certainly different than light. According to Wikipedia “heat is defined as an energy transfer to a body in any other way than due to work performed on the body.” IR (and other wavelengths) often produce heat when they increase the energy of an intervening substance (air, water, whatever). However, a stream of energy traveling thru the vacuum of space is not “heat” – it’s got to interact with something; otherwise, it’s just energy. #19 – fire doesn’t have a “speed,” anymore than there’s a speed of water. Interesting question, though.

  46. Vampire jets out in the daylight tsk tsk tsk never smart.

  47. Reminds me of the intense x-rays from a thermonuclear primary that cause fusion in the secondary by getting there before the shockwave. On a different note, Freeman Dyson causes the design of the Tomahawk elegant and beautiful, and then of course regrets that people working on it could have spent their talent more productively elsewhere.

  48. Tensor

    The results and effects of the pulse of light (or more properly EM) has been know since the early fifties. As a matter of fact, that EM pulse from an Atomic weapon, in the form of X-rays, is what is used to compress the fusion material in Hydrogen (or thermonuclear) weapons.

  49. Dainn

    I’m adding this factoid to the mountain of evidence that 911 was an inside job.

  50. Nemesis

    @ #27

    PS. Interesting that nobody ever says “the speed of heat travels faster than sound” which is as accurate as saying light does – or is it?

    It is true- only in some cases- by scientific definition.

    The heat is carried at the speed of light only in the form of radiation. So, you’d be correct if you asked “does speed of radiative heat travels faster than sound?”.
    The heat transfer, on the other hand,is much slower unless there is an ignition source right near the source of the radiation (then the heat is from the flame, not the radiation).

    Think of it like this.

    You’ll need two identical steel plates, daylight, vocal chords and one co-experimenter.

    First, place one of the steel objects in the sun until it is sufficiently hot.

    How long did it take for the first plate to heat up?

    Second, go outside with your friend and the other room temperature steel plate.

    Third, one of you should take the other (cool) steel plate to place next to the plate that is already hot (from the sun’s radiation), briskly move a hundred yards apart and yell at him.

    What happened first?

    Hopefully, you heard the voice before the plate became hot, or you live way to close to your solar system’s sun.

    Maybe this is a bad explanation, for I am no scientist. Heat only travels faster than sound when it is in the form of radiation, but the heat, itself, is still only transferred through the medium at the predetermined natural rate.

    I just hope I worded it right, so I’m not tarred and feathered.

  51. Nuke3d

    Cool pics, but I’d also say that it’s shrapnel from the rocket body that’s causing this effect…

  52. MadScientist

    I remember those photographs when they were first printed; it doesn’t really seem like that long ago, Perhaps senility has set in.

    I don’t buy the explanation of the radiant energy setting it all alight like that; I suspect the scene was loaded with incendiary material of some sort. Think about it – radiant energy punching through the wings, igniting the fuel, burning through the wings and spilling onto the ground and setting the ground on fire all before the fireball even got to the aircraft? I don’t think so. I might buy the radiant energy setting off the incendiary material but hey, if they fiddled with the scene to produce nicer effects, who knows what else they did – photodetector to electronically trigger incendiaries and explosives? A high enough radiant flux could cause extremely high localized heating and vaporization of volatiles (including paint) … but still, with the little information available I’m suspicious.

    @Nemesis #49: You need to work on the definition of “heat”. Heat is a measure of the average kinetic energy of molecules, which is related to the mass of the molecule and its speed. Radiant energy is light and although we think of this as “heat”, that perception is incorrect. We perceive the radiant energy as heat because it is absorbed and causes a temperature rise in whatever absorbs it. Transmission of sound depends on molecular collisions which in turn depends on the speed of molecules, so it is no surprise that it is in fact dependent on the temperature and pressure of a gas. Well, this applies to liquids and solids as well but the gas model is the simplest and easiest to verify.

  53. t-storm

    The target looks like an A-5 which has aluminum-lithium allow and titanium wings. Conventional explosives explode at many times the speed of sound so it wouldn’t be the shockwave.

  54. Jeeves

    Here’s my hypothesis, based on the video of the same test that some people have posted. What you see is the dust and debris kicked up by the shockwave and some of the shrapnel from the missile, being lit by the light from the explosion. I’m not sure the heat from this kind of explosion would actually cause this kind of target to burst into flames, unless it is engulfed in the fireball. And if you look at the video that clearly does not happen.

  55. I don’t know. The explosion has “gassy” spikes which extend a long way…sort of like supersonic bullet like debris, that travel faster than the cloud. Also, note that the underside of the plane bursts into flames at the same time as the upper side (the flames have similar dimensions). How could infrared radiation coming from above ignite the underside of the plane?

  56. Would it be possible to focus a nuclear blast?

  57. Nemesis

    @#49

    I never defined anything, I only tried to answer the guy’s question, but I failed to put quotations on the first paragraph, thus failing to allude to the fact that it wasn’t my statement. I’ll put in quotes for clarity:

    “PS. Interesting that nobody ever says “the speed of heat travels faster than sound” which is as accurate as saying light does – or is it?”

    The quote was then followed by my attempt to answer the “or is it” portion of his question.

    I should have just said no, heat doesn’t travel faster than sound and the two concepts aren’t related.

    Sorry, but I can’t stand to be corrected for something I never said. Next time I need a term defined, I’ll consult http://creationwiki.org. ;)

  58. Gavin Flower

    @ Rhacodactylus #46

    I have seen an RAF Vampire fighter jet, they have twin tail booms, and a single engine.

  59. Tensor

    @55 Ultraholland. Thermonuclear (hydrogen or H-bomb) bombs focus the X-rays from the Atomic bomb triggers. Or more properly, they use the X-ray radiation from the Atomic Bomb to cause material inside the H-bomb act as if the X-rays have been focused. There is some disagreement among unclassified sources as to what exactly happens, whether it is actual radiation pressure or a physical pressure, due to radiation effects, that compresses the fusion fuel.

  60. 55. ultraholland Says: “Would it be possible to focus a nuclear blast?”

    Yes. In fact, that’s exactly how Orion worked (the nuclear pulse program, not the sorta/kinda return to the moon program just cancelled).

    The biggest theoretical advance to come out of Orion was the nuclear shape charge. They formed the fissile material into a specific (I believe still-classified) shape that caused the reaction to proceed in a manner such that 85 to 90% of the photons generated headed in a narrow cone. You aim that cone at the pusher plate and you’re off!

    BTW, the point that everyone seems to be arguing above is also how you got “push” out of the explosion. It wasn’t the plasma impingement or remaining debris from the device that did the pushing, but rather the momentum exchange of the photos bouncing off the pusher plate. Some of the other research was how to keep the plasma cloud opaque longer so that the photons might have repeated bounces off of the plate before disappearing into space. They found that a disc of polypropylene (yes, the plastic you make bottles out of) sitting on top of the core did the trick.

    Other fun facts about Orion: The estimated usage for a trip to Mars and back was 1,500 to 2,000 devices of about 100Kt each. During the powered portion of the flight they’d be detonated at 4/sec. Even so, the total “plasma time” on the pusher plate for the whole journey was less than one second!

    - Jack

  61. me

    Radiant energy can set fire to aluminium, or even steel. If laser cutting a hole in steel, you can turn off the laser after flashpoint and just keep the oxygen on, and the burn will finish the hole. Besides, the fuel wont ignite until it can get to some oxygen, which I think hasn’t happened till the third frame.

  62. Spence

    Yow, quite a lot wrong here.

    Heat and blast effects from a conventional warhead are actually surprisingly small. It’s related to the whole inverse square law of energy dissipation. Even for a tomahawk (which has “no small warhead”), a miss of that magnitude, the blast is going to be utterly ineffective.

    Range is extended on warheads by adding fragmentation effects. The total energy carried by the fragments still drops by inverse square, due to the spread of energy, but they carry this energy in little, highly damaging, parcels.

    These parcels rupture fuel tanks, weapons etc. on the object being struck and (because they have just been ejected by a violent chemical reaction), they are pretty hot, so tend to set fire to stuff.

    We are seeing an awful lot of fire there though, more than I would suspect from a conventional fragmenting warhead – and in places where there is nothing obvious to set fire to. My first guess would be that the fragments are something like tungsten. Tungsten is an expensive fragment material, but it is pyrophoric, and tends to set fire to anything it hits.

    You can see the lines the fragments are taking. They seem to “outrun” the smoke cloud because they have more mass per surface area, and are slowed less by drag through the air.

    Back to school with you, Phil. Your explanation is unconvincing.

  63. MadScientist

    @Blakut#54: I think Dave@8 has got it. There was high-speed shrapnel that already tore holes through the aircraft so there may have been fuel sprayed about and able to ignite. You can easily see the grey tentacles around the fireball – probably condensation due to the shrapnel compressing the air, similar to the “shock collar” seen on large rockets. As Jeeves points out in #53, the aircraft is probably not even on fire at this stage – what appears to be fire is light from the fireball being scattered by particulates kicked up – sand, maybe fuel if shrapnel did tear through the aircraft and scatter fuel, and simply reflection off the surfaces of the aircraft and on the ground.

  64. Kaleberg

    There is a very good analysis of this effect in the book Project Icarus based on a graduate course at MIT back in the 70s. It’s kind of neat. The analysis of the impulse produced by detonating a nuclear weapon on (or in) the target meteor was great. It was written by the nuclear science students who were familiar with the relationship between weapon detonation force and crater size in terms of mass displaced and with what momentum. The aeronautics and astronautics team dealt with the liquid fueled rockets that were standard issue back then. (The idea was to use off the shelf equipment, assuming your shelves were NASA and the Department of Defense.) The logistics of liquid oxygen evaporation alone were fascinating as they could only launch equipment so quickly from earth, but desired a controlled salvo to be fired from orbit. (Mind you, they still had Saturn Vs back then.)

    It’s a great book. Interestingly, the revised edition was reissued by MIT Press after the movie Meteor was scheduled for its late 1979 release. I never saw the movie, so I have no idea of how good or bad it was.

  65. Kash

    Uhhh…. hearing things like “speed of heat” kinda make my hair crawl. While it’s a valid term, in so much as it makes sense in english, can’t we all get a little precise?

    Fundamental methods of heat transfer include conduction, convection, and radiation.

    Conduction is why you suddenly drop your wiener roasting fork and scream. It was cool just a second ago!

    Convection can and would transfer heat to the plane in the above example, but convection requires a fluid medium. As in the fireball heats the atmosphere which then heats the plane. That’s not the case here.

    Radiation, on the third hand, is the culprit here. Once I drove past a large building on fire with the car windows rolled up. I was momentary shocked to find my face warmed up by the blaze despite the car windows. “Ahhh… radiation”, as I remembered my thermodynamics.

    Actually, I’m kinda glad Phil used the term “light” rather than “radiation”, given all the hair splitting going on.

  66. Robert

    The detonation speed of the main charge is hypersonic, close to orbital velocity. The “shrapnel” is accelerated to velocities approaching these values and easily outruns the visible fireball (the cloud, not the light) and the shock front. If you look at the image you can see that there are spikes of light going right through the plane’s structure and they all radiate from the center of the detonation. Notice also that the ground is being hammered by impacts. What y’got there is an instant meteor storm. We know how fast solid debris can move out of a high-explosive detonation; that’s sufficient to blow the hell out of an aluminum aircraft at close range. No need to cite a relatively weak thermal pulse.

  67. Not to be a downer, but these weapons are made to destroy. I don’t find anything cool about it.

  68. Dave

    Others have said it before (Spence and Robert giving succinct explanations), but it appears that the IR from the explosion has little to nothing to do with the plane catching fire. Rather, it is high-velocity shrapnel which outran the fireball.

    In the video of this test, you can see dirt being kicked up by thousands of impacts, as though someone took a huge blunderbuss and fired it directly downward.

  69. Cusp

    IR photons are not “heat”. All photons carry energy and so can be regards as heat. Our water based bodies are quite good at absorbing IR photons, but sit in the Sun for a while and you’ll feel the effects of UV dumping energy into your skin.

  70. We know the Radiative power law. We can use that to see how hot should the blast products be to be able to radiate heat that would cook off an airplane. I think you’ll need a nuclear blast to set things on fire through radiative transfer, no?

  71. Bob Hamilton

    To answer how the technology has changed; the navigation accuracy has improved quite a bit. So now you would find that same missile exploding a lot closer to the target and possibly hitting the target directly! The improved accuracy lessens the need for as massive an explosive payload which can then be used for additional fuel, extending the range of the thing. Meaning it can fly farther before flying into your targets pants pocket.

  72. Bobby Crosby

    They probably would not waste an entire plane that could be used later, they would just blow a hole in the runway so they can’t take off.

  73. NelC

    Oh, foo. Too many links in my post.

  74. Matt Polson

    The airplane is burning because it was soaked with gasoline prior to the missile arriving. It was ignited by the very high velocity fragments from the warhead casing, which travel faster than the blast wave. The initial velocity of the fragments is on the close order of a mile a second, and they are quite hot. The fragments are hot because they were severely shocked by the high explosive, and by friction traveling through air at extreme velocity. They don’t melt, but they are hot enough in fact to ignite the gasoline vapor surrounding the target aircraft. The flash of multi-spectra light from the high explosive in the warhead really isn’t intense enough to ignite the fuel. In the large photo you can see fuel burning on the ground surrounding the target. I suspect that the gasoline was used to make a more spectacular photo. A large part of the fireball where the missile detonated was caused by residual fuel in the missile. The target was not very far from the missile warhead, so I would expect the aircraft was smashed and torn apart when the shock wave itself hit it.

  75. Stephen Johnson

    Electromagnetic radiation (EMR) is NOT the culprit here – assuming, for the sake of argument that the airplane being blown up weighs about 20,000 kg, is made of Aluminum, and we’re heating 50% of that mass up by 500C with light energy, we have to deliver roughly 900 Megajoules of energy to the target.

    Taking a SWAG that the Tomahawk is 25m away from the target, the target cross section is 200m^2, the EMR is evenly distributed in a spherical pattern, and that a wildly optimistic 25% of the explosion energy goes into EMR, the explosion needs to be ~1.4 X 10^11 Joules. If we take the explosive as 2 X TNT efficiency, we’d need a 17 ton warhead, and the Tomahak only carries 500kg.

    All the above numbers are, Ithink, pretty wildly optimistic (not that I know from missiles) My money would be on Dave from #8′s explanation.

    Thepic is, however, seriously cool.

  76. Spock

    Phil,

    A few assumptions are incorrect in your damage assessment. I can tell you that the middle picture is later time than the initial light that is caused by the warhead. I can also tell you that fragments from the fractured warhead are traveling faster than the fireball. The light on the airplane is mostly from impacts of the case fragments against metal, or sand (as can be seen on the ground).

    The initial light from the warhead comes right after the warhead “cracks” open, and is much brighter than the pictures shown. Still quite a bit of energy, but nothing like the transferred ~mv2 that are all of the incoming fragments.

    Cheers, and keep up the good work.

  77. Gruneisen

    It is also important to note that heating of the aircraft skin could have been caused by several different phenomena associated with blast physics. While I agree that there probably was some significant heating associated with absorption of infrared radiation from the initial blast energy release, the shockwave also expands hypersonically within the vicinity of the initial blast. The pressures associated with a blast wave in air can be extremely high – on the order of 100,000 – 200,000 psi (depending of the explosive, case material, etc. these are just ball-park figures). Granted, the shock pressure drops off rapidly, not only from expansion but also due to energy loss as the rarefaction wave which trails the pressure wave (at the particle velocity, not the wave velocity, thereby traveling at a higher speed than the shock front) ‘catches up’ to pressure wave, causing it to decay to a normal pressure pulse. Even with these effects, the pressures, and therefore temperatures, associated with the blast front are extremely high and can cause a large amount of heating on whatever surface they are incident to.

    Interestingly enough, the shock pulse can also be a significant source of momentum during a blast event, however, the reaction speed of the structure is many orders of magnitude lower than the speed of the shock wave. Also, the shock pulse does not transfer momentum well across materials with a large impedance mismatch, such as steel and air. This means that the shock wave will induce a stress wave in the airplane structure, but will not cause large scale deformations in the structure – these will come from the pressure pulse of the expanding gases.

    Shock phenomena are highly dynamic events which are very interesting and difficult to understand – many of the events are not intuitive. Therefore, high speed cameras and simulation play a large roll in understanding the different events and the influence of each component on the overall event.

  78. nunyac

    I think that for the purposes of these test PICs, “heat” should be interpreted to stand for “high exposive anti tank”. See “http://en.wikipedia.org/wiki/High_explosive_anti-tank_warhead”
    for possible further explanation.

  79. Messier Tidy Upper

    @51. Nemesis : Thanks. :-)

    If I had been more than just half-awake at the time I’d probably have realised it was a silly question.

    I was meaning “heat” as in infra-red radiation thinking in this sense “light” and “heat” are the same thing – forms of electromagnetic waves-particles. However, yeah, I was wrong & they aren’t exactly the same thing. I stand corrected.

  80. asdfsdf

    With the above posters with regards to the shrapnel. I believe later versions of Tomahawk use submunitions, but that is clearly shrapnel punching through the aircraft. Not sure where the flames come from; the fuel tanks may be full. If fuel is full it is fuel being blown through tear by force of impact; if not, it is probably aluminum that ignited from the heat increase due to force of impact.

    @26

    That is completely wrong. Let’s start at the top.

    Shaped Charges do not direct explosions. They use a copper cone with the concave side facing the target and the opposite side lined with explosives. When the explosions detonate, they form the copper cone into a hypersonic jet of copper which has the energy to cut through a significant amount of steel, up to several feet on the big ones. When the jet reaches the inside of the vehicle it breaks up, spraying molten copper around the crew compartment, injuring or killing the crew and igniting the vehicle. On a properly designed western tank, with composite armor, spall liner, wet stowage for the ammunition, fireproofing and damage control systems, a penetration will usually destroy everything in its path, disable the tank, but leave most of the crew alive. On the T-72, a penetration will frequently cause a catastrophic detonation of all the rounds in the main gun autoloader.

    Shaped Charges are also known as HEAT rounds, which means high explosive anti-tank. This is in contrast to the British designed HESH, High Explosive Squash Head, which consists of plastic explosives within a thin metal core. The explosives plaster against the armor and then detonate, spalling the interior of the tank armor. They are devestating against buildings but obsolete against tanks with spall liners. The third type of round is the APFSDS, the Armor Piercing Fin Stabilized Discarding Sabot round. This fires a superdense high speed dart with an extremely high cross-sectional density. This dart attempts to penetrate the armor through shear push, and is state of the art. However, APFSDS requires a high-speed gun in order to be effective–no missiles or rocket launchers, generally (exception is LOSAT).

    The Hellfire Missile has a tremendous destructive capacity no matter the warhead. The HEAT warhead is very versatile, however. Most of the volume of a heat warhead is still explosives, and heat warheads are powerful enough to demolish heavy earthen compounds. The hellfire HEAT warhead weighs 9kg, which is enough to demolish almost any building. Even without a warhead, an impact from a 100lb missile with a catastrophically detonating solid-fuel rocket is enough to destroy any unarmored vehicle. The shrapnel sleeve was added to increase the radius of the killzone to beyond the radius of the blast; for this reason grenades are manufactured with and without shrapnel sleeves, etc. You may be thinking of the thermobaric upgrade for the Hellfire, which increases blast duration and effectiveness versus structures and caves. Your anecdote was incorrect.

  81. scribbler

    Quote: “They formed the fissile material into a specific (I believe still-classified) shape that caused the reaction to proceed in a manner such that 85 to 90% of the photons generated headed in a narrow cone.”

    Unquote: Can you say death ray? Sure, I knew you could…

  82. 90. scribbler Says: “Can you say death ray? Sure, I knew you could…”
    :-)

    - Jack

  83. Bahdum (aka Richard)

    I’m surprised no one else shouted out “pareidolia” or “face” in that 3-pic panel up top.

    Kinda ghostly half of a face, but it looks like a eye in shadow, a big honker, part of a mouth, and he looks like he’s balding.

  84. ds0934

    Impressive: IF you’re fighting a conventional war. Absolutely USELESS against terrorist cells.

  85. Messier Tidy Upper

    @ ^ ds0934 :

    Not if you find the cave the terrorists cowering in – then use the bunker buster version.

    Or use them en masse to take out the nations that are supporting, funding and arming the terrorists.

    Terrorists are flesh and blood and, yes, they can be taken out effectively by airstrikes like that. Israel has disposed of a number of Hamas bosses this way & the US has also removed some Al Quaida leaders by airstrikes often using missiles fired from Predator drones. Plus Sri Lanka has ended its Tamil Tiger terrorist threat by vigourous and ruthless military action.

    Absolutely useless then? :roll:

    NOT at all!

  86. I like the “Stuff” theory. There is visible stuff around the top of the expolosion, followed by a black trail (stuff smoke?) far enough from the center of the blast to define a sphere of sufficient size to include the aircraft. I suspect that what looks like burning fuel on the ground around the aircraft is a distorted secondary explosion from the aircraft itself.

    Dave’s photo does seem to show stuff-tracks down near the plane. The visibility of the black-trailed stuff tracks around the top and not bottom of the explosion may be an effect of the light. A different view or film or something may show a symmetrical or somewhat distorted halo of extra fast stuff all around the blast.

    But what do I know, I’m an anthropologist. From an anthropological perspective, the conspiracy theories may be more interesting …

  87. MaDeR

    @MTU:
    “Or use them en masse to take out the nations that are supporting, funding and arming the terrorists.”
    Then you will be very surprised, like your retarded republican idols: count of terrorists will rise, not fall.

    I remember when I read some article (unfortunately I cannot provide link now, this was long ago) that amount of terrorist attacks against USA and their allies grew many times after attack on Iraq – and that was calculated WITHOUT counting attacks in Iraq itself.

    Good job, Bush. As we can see, carring democracy on bombs works. And hey, if Tomahawk would by mistake (or not) trash in my house killing my family, or american ubermenshes raping and personally killing said family, or other collateral murder, I would seriously consider healing american occupant infestation with a few grams of lead, or even with one personally done last bang. Of course, this is not only about USA – any occupant will get same treatment.

    Fortunately for me and everyone involved , my country probably will not be invaded by USA any time soon.

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