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Space

A Strange Streak Imaged in Australia 825

Posted by CmdrTaco from the but-what-does-it-mean dept.
Koyaanisqatsi writes "Today's Astronomy Picture of the Day presents a challenge worthy of a large audience: as it says, "Meteor experts don't think it's a meteor. Atmospheric scientists don't think it's lightning". An intriguing dark streak and bright flash that defies explanation showed up on some cloud monitoring pictures. The forumsetup to discuss it is currently hosed, so perhaps fellow slashdotters can shed some light over the mystery?"
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A Strange Streak Imaged in Australia More

A Strange Streak Imaged in Australia

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  • It's old news... (Score:5, Interesting)

    by CodeWanker ( 534624 ) on Tuesday December 07, 2004 @11:03AM (#11018037) Journal
    but when this pic surfaced the first time, people speculated that the flat trajectory meant it had to be a tiny meteorite, with the flash resulting from the rock hitting a street light. a 1 in a billion photo, I imagine.
    • The flash is exactly aligned with the top of that pole or light. Could it be the sun reflecting off of glass or copper at the top of the pole? Not sure if that could explain the line though.
      • If it was reflecting right back at the camera, it could certainly result in that line.

        It wouldn't reflect directly back, but at a slight angle. The light hitting the lense at an angle would make one side long. In this case....very long.
        • Line up the three images in order and tab through them. THe time between each image is very short. Therefore the "line" was in for an extreemly short period of time. To me, the line looks like what you would see had a string or hair passed in front of the lens as it were capturing that frame. The glint on the end could simply be something on teh end of it. First thing that comes to mind would be a spider [xs4all.nl]

          "the spiders can fly by wire, called "ballooning". The spider raises her abdomen and releases a thread

      • Re:It's old news... (Score:4, Informative)

        by CyberGarp ( 242942 ) <`gro.ttebraG' `ta' `nwahS'> on Tuesday December 07, 2004 @11:32AM (#11018498) Homepage
        I've got a photo at home of a statue of Sophia. The camera caught a lens flare off the top of her head going towards heaven. I thought it was a wonderful lens effect I couldn't have made if I tried. I think it's either an unusual lens flare, or as another poster mentioned, an insect flying near the lens out of the focal range. Shawn
    • In the caption below the photograph they say that the streetlight has been inspected and no damage was found.

    • No way (Score:3, Insightful)

      by PhysicsGenius ( 565228 )
      It's clearly an artifact. If the flash at the end of the streak was something "out there", it would have to have either hit the water or the light. The after pic shows no waves and the pole is unharmed--there's no even any "smoke" left. It's hard to judge how much time has passed, but it can't have been more than a few seconds. (On the far right is a speeding motorboat and he only gets a little ways between each frame.) With no fragments or smoke just a moment later, it has to be an artifact of some ki

      • Re:No way (Score:5, Funny)

        by dangermouse ( 2242 ) on Tuesday December 07, 2004 @12:03PM (#11018937) Homepage
        It's clearly an artifact.

        Yes, an ancient, alien artifact, pregnant with long-dormant, world-ravaging evil, which will no doubt unleash terrible plague and death and destruction the world over, consuming the entire human race in an unimaginable apocalypse, only possibly averted by some unlikely everyman hero who has heretofore been overlooked by society but who will, no doubt, be immortalized by his deeds on the day the evil is returned to this artifact and banished forever.

        Clear as day. It's right there in the photo.

      • Re:No way (Score:5, Funny)

        by ultrasound ( 472511 ) on Tuesday December 07, 2004 @12:21PM (#11019187)
        Actually, additional analysis here [img111.exs.cx] shows a slightly more energetic explosion than the original image suggests.

  • My view (Score:2, Insightful)

    by oexeo ( 816786 )
    Seriously, it just looks like the guy needs to clean his camera lens to me.

    • Re:My view (Score:5, Informative)

      by interiot ( 50685 ) on Tuesday December 07, 2004 @11:07AM (#11018104) Homepage
      Except that camera was periodically taking pictures, and the picture right before [nasa.gov] and the picture right after [nasa.gov] don't show any problems on the lens.
      • the picture right before and the picture right after don't show any problems on the lens

        What was the frame rate?

        • Re:My view (Score:3, Interesting)

          by Magic5Ball ( 188725 )
          EXIF data says the photo was shot at 1/20 at f5.6. The before, during, after photos were taken at 15s intervals.

          Assuming that the distance between the bulldozer and the surface anomoly site is 100m, if this were a projectile, it would be moving at about 2 kilometres per second.

          Note that the flight path appears slightly parabolic (bulges up), indicating that some non-gravity acceleration is involved.

          Also, why are we assuming that this projectile originated from the sky and not from under the water?
    • In response to my own comment, either what I said above, or it's the smoke trail from a plane hitting the ocean. And since when did "bright streak" mean "dull gray streak"
      • Before someone corrects me, I'll do it myself: The article or summary didn't actually say "bright streak," the summary said "dark streak and bright flash."

    • Re:My view (Score:2, Redundant)

      by cjpez ( 148000 )
      Obviously if the guy's lying about various things, all bets are off, but apparently this pic was one in a series set up to take pictures automatically or something, and they posted the pictures directly before and directly after this one, with no streak apparent. I mean, the guy could be lying about any number of things, but assuming that he's telling the truth, a dirty lens is unlikely to clean itself inbetween shots.

  • IT has to be! (Score:3, Funny)

    by HBPiper ( 472715 ) on Tuesday December 07, 2004 @11:04AM (#11018048)
    That tiny rocket from Krypton preparing to crash land on that old coot Kent's farm!
  • It had to have been something in the development process. IANAFD (I am not a film developer) Could the film have been somehow kinked? I can't buy the fact that it is a freak astronomical event, even though it must have peaked enough people's interests to make it to NASA's picture of the day.
    • The part where it intersects with the exploding street lamp (or whatever it is) would seem a bit coincidental if it were just a film flaw

    • Re:Um, flaw in the film? (Score:5, Informative)

      by suso ( 153703 ) on Tuesday December 07, 2004 @11:14AM (#11018244) Journal
      Um, film? It was a digital picture to begin with. Check out this in the header of the image:

      uExif
      Canon
      Canon PowerShot G3
      ACD Systems Digital Imaging
      2004:11:25 15:20:49
      0220
      0100
      2004:11:22 18:52:52
      2004:11:22 18:52:52
      IMG:PowerShot G3 JPEG
      Firmware Version 1.02

      • Re:Um, flaw in the film? (Score:5, Insightful)

        by pdh11 ( 227974 ) on Tuesday December 07, 2004 @11:25AM (#11018402) Homepage
        Canon PowerShot G3

        My guess is a very bright event (the failure of the streetlight, probably) causing CCD overexposure and subsequent temporary ill effects on the rest of the CCD scan line. Any Canon geeks in the house who know about the CCD scanning direction of a Powershot G3 and can compare it with the streak "trajectory" angle?

        Peter

        • Re:Um, flaw in the film? (Score:5, Interesting)

          by pslam ( 97660 ) on Tuesday December 07, 2004 @11:42AM (#11018630) Homepage Journal
          My guess is a very bright event (the failure of the streetlight, probably) causing CCD overexposure and subsequent temporary ill effects on the rest of the CCD scan line. Any Canon geeks in the house who know about the CCD scanning direction of a Powershot G3 and can compare it with the streak "trajectory" angle?

          I've had all sorts of annoying artifacts like this on my image capture setup at home, but generally overloading the CCD produces horizontal and vertical streaks only, which would follow the layout of the CCD (rows and columns?) The image could still be explained by either:

          • The CCD being deliberately mounted at an angle in the G3 (perhaps to reduce aliasing effects).
          • The bright spot caused lens flaring towards the top level just before the shot, with nearby pixels being dimmed in the image taken very shortly after.

          My theory is the bright flash is actually sunlight reflected off the lamp and either overloading the CCD or causing a lens flare just before the image, resulting in this artifact. I get that a lot with cars going by my camera setup at home, especially at sunrise and sunset. The only difference I get is that they're all perfectly horizontal and/or vertical.

        • Re:Um, flaw in the film? (Score:5, Informative)

          by jridley ( 9305 ) on Tuesday December 07, 2004 @12:18PM (#11019145)
          Nope, CCD blooming happens primarily vertically, sometimes horizontally. Never on an angle. That flash isn't bright enough to cause that massive of an overexposure, and blooming causes the overexposure to bleed into the rest of the column/row, so it would be brighter, not darker. Also, blooming is typically symmetrical from the event, this image has the line going out only in one direction.

        • Re:Um, flaw in the film? (Score:5, Informative)

          by pdh11 ( 227974 ) on Tuesday December 07, 2004 @02:09PM (#11020830) Homepage
          the streak "trajectory" angle

          The streak angle, BTW, is exactly arctan(2/3) -- the streak goes two pixels up for every three across. (It goes 652 pixels up and 978 across, which is less than 1% different from 2/3, smaller than the error of me pointing at things in the Gimp.) To me this makes it very likely to be an artifact.

          Peter

    • Timestamps on the images (Score:5, Interesting)

      by suso ( 153703 ) on Tuesday December 07, 2004 @11:23AM (#11018375) Journal
      Actually, here is something revealing, it seems that his before and after images are reversed:

      $ strings strangebefore_pryde_big.jpg | head
      uExif
      Canon
      Canon PowerShot G3
      ACD Systems Digital Imaging
      2004:11:25 15:23:11
      0220
      0100
      2004:11:22 18:53:07
      2004:11:22 18:53:07
      IMG:PowerShot G3 JPEG
      $ strings strange_pryde_big.jpg | head
      uExif
      Canon
      Canon PowerShot G3
      ACD Systems Digital Imaging
      2004:11:25 15:20:49
      0220
      0100
      2004:11:22 18:52:52
      2004:11:22 18:52:52
      IMG:PowerShot G3 JPEG
      $ strings strangeafter_pryde_big.jpg | head
      uExif
      Canon
      Canon PowerShot G3
      ACD Systems Digital Imaging
      2004:11:25 15:22:47
      0220
      0100
      2004:11:22 18:52:37
      2004:11:22 18:52:37
      IMG:PowerShot G3 JPEG
      $

      • Re:Timestamps on the images (Score:5, Funny)

        by bcattwoo ( 737354 ) on Tuesday December 07, 2004 @12:35PM (#11019439)
        Ah, but this was in Australia. In the Southern Hemisphere clocks run counter-clockwise (well, still clockwise to them), so time runs opposite of what it does in the Northern Hemisphere.

  • Source of the line (Score:2, Interesting)

    by Lev13than ( 581686 )
    I'd say round paintbrush, 20 pixels, black with 10% opacity.
    Either that or he needs to clean his camera lens.
  • Don't be alarmed. Okay, panic a little if your get your water from there.
  • A poor Photoshop job?

  • Ironic username for submitting this story (Score:3, Interesting)

    by suso ( 153703 ) on Tuesday December 07, 2004 @11:07AM (#11018102) Journal
    Koyaanisqatsi was the title of the 1983 film which has the prophecy:

    "If we dig precious things from the land, we will invite disaster. Near the Day of Purification, there will be cobwebs spun back and forth in the sky. A container of ashes might one day be thrown from the sky, which could burn the land and boil the oceans."

  • That streak is awful straight (Score:4, Interesting)

    by Lonesome Squash ( 676652 ) on Tuesday December 07, 2004 @11:07AM (#11018103)
    for any sort of natural phenomenon. It suggests a photographic artifact of some sort. Is the flash definitely related? It certainly appears to be coming from the end of what the APoD caption identifies as a light pole, which is not working. Could it have failed with a sudden flash? Could it coincidentally have occurred at the same time as the streak artifact?
  • Possibly the exhaust trail from a Surface-to-Air Missle?
  • Fireworks? What are the time intervals between the 3 photos?
  • Perhaps examining the light pole that appears to have been hit would provide a clue? Did anyone do that?
  • i cant resist...i for one welcome our new straking overlords

    • Re:UFO? (Score:5, Funny)

      by dark_panda ( 177006 ) on Tuesday December 07, 2004 @11:13AM (#11018228)
      There was no alien. The flash of light you saw in the sky was not a UFO. Swamp gas from a weather balloon was trapped in a thermal pocket and reflected the light from Venus.

      Nothing to see here, move along folks.

      J

  • Sorry, everyone! (Score:5, Funny)

    by fireboy1919 ( 257783 ) <rustypNO@SPAMfreeshell.org> on Tuesday December 07, 2004 @11:09AM (#11018150) Homepage Journal
    That was me.

    I was trying out my new death-ray. I had it miscalibrated so that you could see it.

    Don't worry about it. When death comes and strikes from the heavens for real, it'll be completely invisible.

    -Ming the Merciless
  • It is a super small alien space ship manned by super intelligent aliens no bigger than ants. They failed to judge their trajecotry correctly and slammed into the lamp post on the pier.

    Let us all bow our heads in silence as we remember these small but brave travelers.

  • What amazing lucky! The streak may have existed for a few seconds only and the photographer have shooted it. Is this really serious?

  • What a clear photo! (Score:4, Interesting)

    by Hatechall ( 541378 ) on Tuesday December 07, 2004 @11:13AM (#11018222) Homepage
    What I don't understand is how the "flash" at the end of the streak is so clean of an image. Even with crazy f/stop settings and an ISO equiv of 400 - I would imagine a picture in that light would have to have a shutter speed of at most 1/30th of a second, more than enough time to cause blur even to a slowly moving object. Am I off base here?
    • Am I off base here?

      Possibly but not far off base. The picture was taken by a photographer with a telephoto lense. He was taking pictures of a large area where movement is occurring. I doubt that he would be using a shutter speed as slow as 1/30. I would not take pictures at that distance with less than 1/250 as it would reveal photographer tremors (though he could be using a tripod, but then he would go for 1 /125)
  • I love APOD. I go there daily. My main problem with APOD is the mass reusing of pictures without any way of knowing if the "picture of the day" is a duplicate or not.

    Yes I tried contacting the APOD maintainers as indicated in this previous APOD slashdot [slashdot.org] story :-)
  • Aircraft parts fall off.
    Aircraft toilets malfunction.

    Has the light pole been checked for bacteria?
    Most of the vital parts on an aircraft are built by the lowest bidder.

  • Didn't you see the little silver De Lorean Gull Wing disappear just before the little flash? I suspect it was using about 1.21 Gigawatts of power at that moment...

  • Let's see Watson... (Score:3, Interesting)

    by ceeam ( 39911 ) on Tuesday December 07, 2004 @11:15AM (#11018262)
    From the article:

    Images taken just before and after the above frame show no streak or flash. The light pole near the flash has been inspected and does not show any damage, although the light inside was not working.

    Can we reasonably say that it was just a light bulb blowing off? Streak? Boy, for sure when I get a bright lamp in the frame I have all kinds of streaks going off it on the picture. So - I'd say it's either an optical or digicam artifact caused by the flash.
  • It's the GoldenEye [wikipedia.org]!
  • The photograph shows a flash of illumination, not an explosion. The lamp was inspected, the bulb did not work but there was no physical damage.

    A meteor that hit and caused a flash would have left some external marks. Not a meteor thus.

    Perhaps a photoshop? A simple answer, but somehow less than pleasing.

    No, what we see is the trace of a death ray, shot by a military satellite, able to take out lamp bulbs without any collateral damage. Dear god... these things could be circling above our heads as we sp
  • I have observed this phenomena before when a jet, leaving behind it's contrail, flew between the lower cloud level and the clear sky above. If you look at the picture, the sun is illuminateing the clouds from the right, with a the streak appearing on the left. The plane therefore bisected the path causing the shadow to occur. Now the question is, what was the interval that the pictures were taken in the before and after shots. I have seen this to last a few minutes until the contrail dissipated signific

  • My solution (Score:5, Interesting)

    by troon ( 724114 ) on Tuesday December 07, 2004 @11:20AM (#11018326)

    OK, here's my solution. The light levels are fairly low: the EXIF data from the big image reveals that the Powershot G3 used 1/20s exposure at f/5.6.

    I reckon the streak and the blur are very, very close to the camera, and that the intersection with the streetlamp is conincidence.

    I believe that the mystery object is an insect flying "north-west" (i.e. towards the top left of the camera). The EXIF data tells us that the flash was fired, although goodness knows why any decent photographer would use a flash for that shot.

    The flash on most cameras fires at the beginning of the exposure time, and the insect is captured in flight and out of focus near the middle of the frame. It then continues flying for the rest of the 1/20s exposure causing the black streak.

    Where do I go to collect my prize?

    • Re:My solution (Score:3, Interesting)

      by Anonymous Coward

      You guys have such wonderful imaginations. The fellow who described it as a photographic artifact is as close as any of you get.

      Note that a line inscribed from the sun to the flash at the postition of the light pole is at right angles too the black streak.

      This is whats commonly known as a ''sun dog'', or lens flare, though it is produced in this case from the reflection rather than the sun itself.

      I reached this conclusion after using photoshop CS with the Genuine Fractals scaling plugin on a G4 powermac

      • Re:My solution (Score:5, Informative)

        by jridley ( 9305 ) on Tuesday December 07, 2004 @12:26PM (#11019280)
        This is whats commonly known as a ''sun dog'', or lens flare

        Careful, sun dogs and lens flares are two completely different things. Lens flares are caused by internal reflections inside the lens. Sun dogs are caused by the sun's light hitting ice crystals in the atmosphere and are visible to the eye.

    • photoshopped image... (Score:5, Informative)

      by zebruh ( 838101 ) on Tuesday December 07, 2004 @12:37PM (#11019466)
      Maybe this will shed some light. It's a Photoshop "difference" between the before image and the mystery image, with a bit of levels adjustment to make it more obvious. http://img119.exs.cx/my.php?loc=img119&image=x2fst rangeprydebigdi.jpg [img119.exs.cx]
  • Somebody find Reed Richards ASAP!
  • that the dark streak and the bright artifact do not meet. The streak looks to be "above" the bright artifact, and continues past it.

    Also, the bright artifact has a brighter core that is vertical with respect to the rest of the frame. This could be consistent with a reflection off a cylinder such as a lightpole.

    It's probably just the reflection off my tinfoil hat.

  • Lots of Meteorites hit Australia yesterday (Score:4, Interesting)

    by Shanes ( 141586 ) on Tuesday December 07, 2004 @11:24AM (#11018394)
    Se here [hohmanntransfer.com] for some reports.
  • The streak and flash is the discussion server crashing and burning under the weight of the mighty /.

  • My Questions (Score:4, Interesting)

    by ErroneousBee ( 611028 ) <neil:neilhancock...co...uk> on Tuesday December 07, 2004 @11:33AM (#11018518) Homepage
    1. Is the trajectory staight, or does it drop slightly. Putting a ruler up against my screen indicates it drops slightly, but that doesnt mean anything.

    2. Is it a flash, or is it a steady bright light (like what a meteor head would be). Need to know the exposure time for that info.

    3. Is there any sign of the trail in the after photo.

    4. How long is it before the after photo was taken?

    5. It the flash infront of, behind, or exactly congruent with the pole top.

    6. Is the trail wider at the top than the bottom. If it is, is this dispersion of smoke or paralax and the object was moving away.

    7. Is the image film or digital.

    8. What is the white stuff? Shock front? Something disintegrating? Why is it that funny shape?

    9. Was the light working previously? When was it last known to be working? There may be pictures of it from the night before.

    Well, thats my questions. I think its a meteor.

  • Object hitting the water? (Score:3, Interesting)

    by diakka ( 2281 ) on Tuesday December 07, 2004 @11:38AM (#11018581)
    I didn't notice this until I looked at the before and after pictures in sequence with the main picture. But it appears that the streak may be the trail of some object hitting the water. If you look where the streak meets the water, there seems to be something bright where the streak meets the water that is not in either of the other 2 images.

  • Those pictures have got to be in the wrong order! (Score:5, Informative)

    by PhilHibbs ( 4537 ) <snarks@gmail.com> on Tuesday December 07, 2004 @11:43AM (#11018643) Journal
    Take a look at the way the clouds are moving - I've never seen clouds billowing inwards.
    before [nasa.gov]
    "the" picture [nasa.gov]
    after [nasa.gov]

  • OMG the sky is falling!!! (Score:5, Insightful)

    by gosand ( 234100 ) on Tuesday December 07, 2004 @11:58AM (#11018869)
    Meteor experts don't think it's a meteor. Atmospheric scientists don't think it's lightning

    Paleontologists don't think it is a dinosaur, NASA doesn't think it is a spacecraft, financial experts don't think it will have an adverse effect on the economy, lawyers could be preparing a lawsuit on behalf of Bigfoot for IP infringement, the FDA has said it could have adverse side effect, the White House has declined to comment. Currently the photo is on sale at eBay with the high bid at $785.

  • A meteorite fast enough to vaporize on impact... (Score:3, Interesting)

    by Goldenhawk ( 242867 ) on Tuesday December 07, 2004 @11:59AM (#11018885) Homepage
    Somehow I doubt that a meteorite that was going fast enough to vaporize on impact would leave a *dark* steak in the frame. Secondly, if it was big enough to leave that wide a dark streak, it would make a MUCH bigger impact than that little flash. But moments later, there's no visible sign, even in the water.

    I personally own a similar Canon G-3, and I've never seen a dark streak on the image, even when shooting pictures with a strong point light source (as was speculated for a blowing-out light bulb). In fact, with the G-3, a well known problem is "purple fringing" around bright lights. None of that here, so the bright splotch is probably not that bright.

    I personally subscribe to the "bug in front of the flash" theory.

    (Question: one post suggested the EXIF data shows the flash fired. Why would a halfway decent photog leave the flash on for a distance shot like this? It just risks illuminating the dust between you and the subject matter.)

  • Some numbers (Score:5, Informative)

    by Shillo ( 64681 ) on Tuesday December 07, 2004 @12:20PM (#11019169)
    Ok, I did some work on this...

    First, EXIF fields in the photos... something you should look at first.

    Camera: Canon PowerShot G3
    Date and Time (original): 2004:11:22 18:52:52
    Exposure Time: 1/19 sec.
    Aperture: f/5.6

    And for the photo After:
    Date and Time (original): 2004:11:22 18:52:37

    So the photos were taken with 1/19 sec. exposure, every 15 seconds.

    I took the two images into GIMP, substracted them, brightened the result a lot (using Levels) and ran it through despecle. First, the lamps do look perfectly identical between the photos (or there'd be a spot around the lamp where it changed shape). In fact, the only bright bits that remain (apart from the sea reflections) are the flash and the streak.

    The streak looks conical, at 1-1.5 degrees (I measured roughly using GIMP). It ends before the edge of the picture. It's about 1200 pixels long, in fact. The street lamps are 60 pixels long... Assuming that a street lamp would be on the order of 5-10 metres high, you get about 100-200 metres streak.

    The cloud is VERY visible on the difference image; it has yellow-orange central spot and 2 pure-white spots to the sides; this seems consistent with a central fire and a smoke circle.

    Now I substracted the before and after image and brightened them the same way. I *think* there is a visible dark spot at the place where the white cloud was; however, the image is so noisy that it could just be my imagination.

    I think that the flash and the cloud were from the blown lamp. They dissipated rapidly, but there could be traces left... I'd have to do much better image processing to be able to tell.

    I have no idea whatsoever what the dark streak could be. It doesn't look like a CCD sensor problem - overloaded CCDs leak brightness straight up, as far as I know. I also don't know of any lens flare that can darken the photo. It could be smoke, in which case something would be hitting the street lamp. But that would've caused lots of visible damage.

  • Impact trama, or lack thereof. (Score:3, Funny)

    by Mulletproof ( 513805 ) on Tuesday December 07, 2004 @12:30PM (#11019355) Homepage Journal
    Ok, it's really simple.

    1) It's bright.
    Bright things moving though the atmosphere tend to be very very hot.

    2) It's durable.
    Things that make it this far down tend to be be fairly substantial in nature.

    So now we supposively have a bright, hot, durable object impacting a body of water at high speeds... THAT LEAVES NO TRACE AFTER IMPACT. Steam maybe? A ripple or two? Honestly, would somebody like to run a simulation on a superheated baseball sized rock slamming into the ocean at close to mach? Maybe a golfball to be conservative? Heck, I'm speculating the damn thing might explode just in temperature differential alone when it touches the water, if not angerly boil for a good long time.

    The only conclusion I can specuate where it may have been any substantial object falling from the sky is that one in a billion chance it actually fully vaporized a second before impact. Even so, you'd still have some sort of audio event at those speeds, I'm imagining.

    I'm going for visual artifact or an environmental lighting glitch myself.

  • This is an very common phenomenon (Score:5, Interesting)

    by Thagg ( 9904 ) <thadbeier@gmail.com> on Tuesday December 07, 2004 @12:34PM (#11019427) Journal
    You can see this dark streak almost every day in southern california, or almost anyplace that has contrails visible in the sky. When the contrail goes between you and the sun, you can see a dark band coming down from it. Watch for it!

    Basically, what you are seeing is the equivalent of a sunbeam, except that it's a shadow-beam. A sunbeam occurs when there is a small hole in the cloud, and the light going through the hole illuminates the dust particles and water droples in the air along the path of the light. If the light is strong and the background relatively dark, it is easy to see these sunbeams (or God rays.)

    Shadows through the sky are somewhat harder to see, because the contrast is not as great. When they are dramatic, as in this picture, you have to have the fortuitous situation of looking through a long, well defined slab of shadowed air, with well-lit air on either side. Airplane contrails are the perfect shadow source for this.

    Imagine a 3D volume of a shadow cast by a contrail. It is a long thin slab of shadowed air. If you are within that slab, and looking along it, all the air in that direction is shadowed, for many miles, so the contrast between the shadowed air and the surrounding air is strong.

    A good bit of the light around the shadow beam is not light scattered by dust or water droplets, but is just the same Raliegh-scattered light that makes the sky blue. The dark streak through the sky will be noticably darker and especially less blue than the surrounding air.

    As you can tell, this is one of my favorite (of many!) atmospheric optical phenomena. Once you start to look for them, they are quite easy to see. Occasionally you can see them from natual cloud formations or even topographical or architechural features when the conditions are just right.

    Thad Beier
    • You may well be correct in saying that the streak is a shadow of a jet contrail. But I still wonder why it appears only on this photo and not the previous or subsequent one. The 'flash' could just have been the sun reflecting off the glass in the lamp during the exposure. I've noticed this shadow phenomena myself.

  • Not a flash across the grass (Score:3, Funny)

    by Alain Williams ( 2972 ) <addw@phcomp.co.uk> on Tuesday December 07, 2004 @12:56PM (#11019794) Homepage
    I read the headline and eagerly hoped for a picture of another lady running across a test match cricket pitch .... alas, it wasn't.

  • It's not an artifact: Proof (Score:3, Informative)

    by Drexus ( 826859 ) on Tuesday December 07, 2004 @01:09PM (#11020020) Homepage
    I analysed the images and found that there is reflected light on the water that places the flash very close to the street light. Try this: - Load all three images into Photoshop. - Convert each image to Multichannel mode. - Select the yellow channel only in each image (channels window) - Bring up your curves window "Cmd+M":mac, "Ctrl+M":PC - Set the highlights: input 40% output 0% and the shadows: input 62% output 100% Do this for each image on the yellow channel only (save the curve and reuse it for each image for accuracy) Once each yellow channel is adjusted. (make sure you are not viewing channels in the the channel colour - view yellow as black) Tab through (cycle) each image to see the highlight in the water appear. (zoom out from each image with your keyboard - PS will place them all at the same position on your screen for a still animation). The light reflection you see will be a similar effect produced by lights on the waters edge from a NYC skyline at night - Tall and defused. It's not a bug. There is no smoke. That is a flash near the street light. No camera flash was used, and there is no sun beams present in the scene. I have no other explanation at this time. All I can say is the dark line is not smoke.

  • Bad Science from "The Bad Astronomer" (Score:3, Insightful)

    by mike18xx ( 838191 ) on Tuesday December 07, 2004 @03:43PM (#11022138)
    Bad Science from "The Bad Astronomer" -- On the Bad Astronomy page (which I am unable, for some reason, to create an account on due to the "robot" rejecting a correct letter/number verifier.), "Bad Astronomer" (henceforth, "BA") wrote:
    If this were a meteor hitting the lamp, then the center of the streak should hit the lamp-- if we are to believe the image shows the lamp exploding upon impact, the trail should not have had time to drift. Since the streak misses the lamppost, I assume that this picture does not show a meteor.
    Why are "we to believe the image shows the lamp exploding"? Wouldn't it be an easier assumption that the lamp is simply in the foreground and the bright object is either the incandescent meteor itself or its splash & steam-cloud in the water behind the post?
    Also, a small meteor would have long since slowed to free fall by the time it hit the ground, so the angle of attack would be vertical, not at the 33 degree angle in the picture.
    Bullets traveling less than one-tenth the speed of a meteorite are easily able to miles of atmosphere without slowing to free-fall. A reasonably aerodynamic iron/nickel meteorite could easily slam straight in at an oblique slant angle at still supersonic speed. (The small white arc which is just to the right of the flash/splash is, I maintain, slight condensation attending the atmospheric shock-wave which is visible only from a vantage point along the plane of the shove-wave.) I believe the image shows the impact of a dime-to-quarter-sized meteorite traveling slightly under the speed of sound at splash-down. Not only does it satisfy Occam's Razor with only a single item explaining all features on the image (dark trail, white arc, bright flash), but also represents a phenomena which actually isn't that unusual, and which have been recorded on film on more than one instance before.

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