Strange streak discussion: 2004 Dec 7 APOD

[stonier7@telus.net]

Looks like a streak from a jet, caught just at the right moment

[victorengel]

Excellent diff picture. Certainly better than the one I did. One thing that immediately grabs me is that the "shadow" has both a beginning and an end, both within the frame. This is enough to convince me of the insect theory.

Since nobody has posted this here yet, my try at making a good diff of the pictures: http://images.isja.org/images/strange_diff_pryde_01.png

[Ricky]

This is just a suggestion, but how about fireworks?

If a firework was shot off, there would have to be some kind of flash where it started. It would also leave a smoke trail, and it would be fairly small, probably similar to what appears here. Furthermore, the trajectory would be straight since a rocket is propelled. If you look closely at the bright light, I think I can see a small smoke cloud. Someone check just to make sure my eyes are working.

The only problem I have is with that flash. Unless there was something burning from the launch site afterwards, I don't see how that light would still be there.

Anyways, I'm sure someone is going to be able to find a flaw in this (besides the flash), it seems way to simple, so lets hear em.

[Guest]

This Slashdot comment is my favourite theory:

http://science.slashdot.org/comments.pl ... d=11019427

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.

((deletia))

Contrail shadows are true phenomena, as described above, but they ALWAYS "point" back to the sun. Not possible in this case, because the sun is off to the right in the picture, and the "shadow" comes down from the left.

It's NOT A CONTRAIL SHADOW.

It is a contrail, the shadow does point to the sun, it is behind you, over your right shoulder. The shadow points back to it exactly like an anti-crepuscular ray, only dark instead of light.

[Guest]

I haven't read this entire thread so I don't know if this theory has been advanced already. I think the photo captures the light fixture at the moment of failure and the streak is the shadow cast by part of the hood over the light or perhaps the extension that the light fixture is mounted upon.

[Guest]

Maybe it's a meteor and it just looks like it's hitting the lamp but it's really falling into the water behind the lamp and the white stuff is waves.

[Eric the Redneck]

It seems to me that this is a glint of sunlight on the metal cowling of the mast light. Why? (A) The hazy area to the right is in line with the sunlight source and shows a shape within it, (B) The location of the flash directly on the light is too coincidental, (C) Only reflected sunlight would likely produce that relative intensity and (D) There's no before and after phenomena evident.

The dark streak, while not at perfect right angles to the sunlight source, is basically so. This could be some result of the optics in linear perspective or within the lens or shutter itself.

That's my 2 bits.

Thanks, - Eric Lewis

[johnccole@yahoo.com]

Here's an explanation, and since I'm unencumbered by knowledge, I can speak freely:

The unexplained image is an insect, close to the camera, flying at speed.
As I say this, though, that doesn't explain the trail.

A for effort, nice try.

[Pruden R.]

Have seen this many times as a pilot, from the other side. It is undoubtably the shadow of a contrail on shallow cloud.

[SquishyDave]

I've read this whole thread, and I have some issues that need addressing by the various proponents. Because those people advocating one theory or another have not yet answered some serious questions about their favoured explanations.

Can everyone who thinks it's a shadow of the street light, please address how you cast a shadow across the sky like that, with a little street light.

To those who think it's a meteor, please address that a rock small enough not to explode the harbour or cause noticable effects, would be falling in at least a curved path by the time it hit.

To those who think it's an aircraft contrail, please explain how it appeared and disappeared in 45 seconds.

To those who think it's an insect.... well there has been no objections to the insect thoery that hasn't already been covered. You've covered how it would leave a streak, and why it looks like a straight line, and also that it would not have to be traveling very fast to leave the streak.

Based purely on the fact that the insect theory has been able to answer all the questions thrown at it, I must lean towards it as the most likely. So I will just leave you with a pic of the suspect bug again.

[Prometheus Bound]

http://antwrp.gsfc.nasa.gov/apod/ap010221.html. This could explain the unusual shape of the white wisps to the right of the light area, but would mean the additional coincidence of a precise speed.

One thing is clear, if the dark line represents the path of the object and the object is behind the lamp (as I suspect), then it is moving very fast. Some comments suggest that the line is curved downward slightly, possibly indicating the effects of gravity.

I don't buy the bug, or the lamp exploding (The original question indicates that the light was not working, not that there was glass scattered about or anything else that would have seemed prudent to mention).

I think it is a piece of spacejunk or a meteor, moving at supersonic speeds, glowing due to the heat or atmospheric entry. The wisp is either as described in the link above or the pressure front of the advancing object

[carbno]

I suspect that the effect could have been caused by a charged particle traversing through the camera CCD at about the time of the photo. Since the streak appeared dark, that would indicate that charged leaked out of the pixel capture cells. I suppose that might be caused by a particle of different charge traversing through the detector.

I suppose this could be test easily enough in the lab... set up a digital camera, bring various type of radiation sources near it and see what happens.

I notice that the streak has a width ... it appears to be changing in width, and it appears that the path fades at both top and bottom ends. This suggests that perhaps the particle wasn't perfectly alligned with the CCD sensors and went out of the plane of the image.

What kind of camera, how big is the sensing area?

I'm not a particle physicist, but probably there is one somewhere that know about the CCD interaction with particles and could suggest tests of this hypothesis.

Collin

[Guest]

I don't buy the bug, or the lamp exploding

Why not? I would like some information on how a bug could not make this artifact, otherwise I won't be able to rule it out, and please don't say the bug can't leave a trail, because that has been addressed, and don't say the line wouldn't be straight, because that has also been addressed.

[Guest]

Some people have said that a bug couldn't move fast enough. The flies here in Australia can move at speeds close to 60km/h. I think that would be fast enough to leave a streak under slow exposure.

[pandich]

I suppose, if someone wants to spend the time, a simplified mock-up of the scene could be done in a 3D rendering program that supports particle-based atmosphere effects. We could see if the pole's shadow would in fact appear at that angle and magnitude. Also, if we had the uncompressed TIFF (if the camera in question stores in that format, as mine does) we could look closely at the light pattern for the proper type of len's flaring. This could help validate the authenticity of the claims. Additionally, JPEG compression causes a big increase in the signal-to-noise ratio, particularly at the fine detail level. A TIFF would let us more closely examine pixel's and their neighbors to form a general model for comparison to the region of the event. Differences could give indication as to the nature of the picture.

Other thoughts?

[anbreau]

In my opinion, the mysterious shadow is the result of the street light burning out at the instant the picture was taken. Such types of lights would typically be high wattage and would cause a very brief and bright high intensity flash. The flash would radiate in all directions except where blocked, in this case possibly by the upper part of the light fixture which is large and rectangular. This would explain why the shadow is towards the sky and not the ground. There must have been just enough moisture in the air to allow this shadow to cast.

[Sparky]

Talk about out in left field..... Let's suppose that the location of the lamppost is purely coincidental, and that the flash is actually occurring in the water behind the pole.

What if this were a micro black hole? In its trajectory through the atmosphere, it would change the density, and therefore the refractive index, of the air. When it hit the water, it self-destructed in a burst of energy.

As for the smoke, it is on the near side of the pole; so it is unrelated to the streak and flash.

[pandich]

If we know the cardinal direction the camera was directed towards and the time, weather service data could indicate the relative wind direction. Could the white cloud be gases in an excited state venting from the lamp bulb and blowing/dispersing in the direction of the wind?

[SquishyDave]

I suppose, if someone wants to spend the time, a simplified mock-up of the scene could be done in a 3D rendering program that supports particle-based atmosphere effects. We could see if the pole's shadow would in fact appear at that angle and magnitude. Also, if we had the uncompressed TIFF (if the camera in question stores in that format, as mine does) we could look closely at the light pattern for the proper type of len's flaring. This could help validate the authenticity of the claims. Additionally, JPEG compression causes a big increase in the signal-to-noise ratio, particularly at the fine detail level. A TIFF would let us more closely examine pixel's and their neighbors to form a general model for comparison to the region of the event. Differences could give indication as to the nature of the picture.

Other thoughts?

Why go to all this trouble? We should rule out the simplest explanation first. The insect theory. Why couldn't this be made by an insect?

[daniel]

I am a fan of the particle beam theory, but from a satilite. what better place to do a harmless demonstration? also, I am 17 and full of crazy Ideas.

[Can't use my Bad Buoy]

What an OUTSTANDING photograph!!!!

The photo is consistent with a small, slow [mach 2-5] meteorite burning down through the sky {the reader who posted the enhancement of the differences between the strike frame and those before and after accents either where the shutter opened, combustible material became exposed, or where it appeared through the clouds}.
The meteorite has just entered the water and is in the process of exploding out its entry path as the shutter closes.

Now as to the shockwaves. They are not very intense nor is the explosion thus pointing to a very small object.

As most are aware, an object accelerating past the speed of sound creates a sonic shockwave beginning as it passes through the sound barrier [761.6 mph or 1056 ft per sec. at sea level]. This shockwave forms into an ever tighter cone as the speed increases. Now if you'll pick up a piece of paper and form it into a loose cone, you'll see what I mean. Look into your cone and through the hole at the vertex. Keeping this vertex on the explosion slowly swing the cone to the left till you are sighting directly down the wall of the cone to the exlosion point. Rotate the cones axis so that it is parallel with and would cover the entry trail. It is a weak shockwave and only visible as you look through a few hundred yards of the face. Looking higher or lower than the explosion and you are no longer looking through the full face, now dissipating as the object has just been annihilated a slight distance into the water. The object, had it survived, would have been ahead of the explosion we see exiting through the water entry path.

Now the smaller, round shockwave centered on that same final point of the meteorite's existence is the compression wave from it's explosive demise. Depending upon the explosive [check out the fourth paragraph here] such a wave can travel many times the speed of sound.

Catching these items at the moment of an object's annihilating impact with the Earth is an OUTSTANDING achievement.

Thank you all involved in bring this to me.

[bocab]

take a look at the first picture (the one just before the picture with the flash) in the sequence in the link below, it looks to me like there is a partial shadow there as well, just above the well defined shadow in the picture with the flash

http://the-light.com/Photography/Discussion/meteor.gif

does no one else see this?
If there is a shadow in a different picture wouldn't that rule out the bug theory?

[guest]

I could be a missile fired from an aircraft or some other platform. Offcourse this does'nt seem like a place for target practice, but it could be an accidental firing. I does have the signs of a missile in its terminal phase of flight(a streak and a flash at the point where it hits).

[Guest]

maybe it's an unknown insect which uses jet propulsion

[Burner]

Go back to the simplest of the answers. The light or some object very close to it exploded thus lighting up the sky and casting the shadow. The shadow appears to be jagged only because it is being cast on the puffy clouds making it only appear jagged but would have been straight if the clouds were more dense/packed closer together. Lightning/meteor trails would have lasted long enough for the next picture to have captured a dissipating trail.