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A Strange Streak Imaged in Australia

Posted by CmdrTaco on 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?"

12 of 825 comments (clear)

  1. It's old news... by CodeWanker · · Score: 5, Interesting

    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.

    --


    "Wow. Now THAT'S a lot of angry Indians." - Lt. Col. George Armstrong Custer
  2. That streak is awful straight by Lonesome+Squash · · Score: 4, Interesting

    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?

    --
    Behold the riant ape! Beware, his crooked thumbs!
  3. What a clear photo! by Hatechall · · Score: 3, Interesting

    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?

  4. My solution by troon · · Score: 5, Interesting

    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?

    --
    Ydco co ,df C erb-y go. a Ekrpat t.fxrapev
    1. Re:My solution by Anonymous Coward · · Score: 3, Interesting


      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 to enlarge the picture over 500%. Though there was some lossiness as the reflection area was blown up nearly to screen size, it is clearly a reflection off of the light fixture at the top of the pole.

      Gimme back my prize :P

      mail me: twitch at mw dot merseine dot freakin' nu

  5. Timestamps on the images by suso · · Score: 4, Interesting

    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
    $

  6. Lots of Meteorites hit Australia yesterday by Shanes · · Score: 3, Interesting

    Se here for some reports.

  7. My Questions by ErroneousBee · · Score: 3, Interesting

    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.

    --
    **TODO** Steal someone elses sig.
  8. Re:Um, flaw in the film? by pslam · · Score: 5, Interesting
    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.

  9. Re:It looks like... by LnxAddct · · Score: 3, Interesting

    I am in no way an expert at this stuff, but judgin from the color, streak, projectory, and location (Australia), it look to me like a burning hot piece of some very durable metal that was falling through the atmosphere. A lost satellite best fits that description.
    Regards,
    Steve

  10. This is an very common phenomenon by Thagg · · Score: 4, Interesting

    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

    --
    I love Mondays. On a Monday, anything is possible.
  11. Re:My view by Magic5Ball · · Score: 3, Interesting

    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?

    --
    There are 1.1... kinds of people.