Strange streak discussion: 2004 Dec 7 APOD

[Guest]

The shadow clearly appears to be a contrail. Light hitting a contrail at the right angle would result in a shadow on the clouds. It also appears the shadow passes above a small cloud and comes out the other side. The shadow also appears to end at the horizon and not the light. Clearly a contrail.

The light could be the bulb burning out or simply a ray of sun hitting it. The right side of the water is clearly brighter suggesting more sun hitting it.

Highly likely just a coincedence but I'd go for a beam weapon (more interesting).

[dcigary]

When I saw this, I immediately thought back to my old webcam that I had pointed out the front of the house. Unfortunately, the webcam was pointed into the sun, and it produced sun-struck streaks on the CCD. In this case, the angle and width of the streak in the "mystery image" looks close to mine. Also note that the streak was not visible in low light conditions on my webcam, only when the light level was above a certain limit did the streaks show up. So, here's my hypothosis:

1. Camera has been in use for a while watching clouds.
2. Camera is pointing to the SSW, enough to catch the sun as it travels through the sky.
3. Trail in mystery picture, if you look closely, actually ends at the horizon, not at the post, thus capturing the setting sun.
4. The camera just happened to catch the bulb on the dock going out, producing a large flash.
5. The flash caused the camera to reduce the light level, thus illuminating the streak.

Note I haven't looked into the EXIF data at all from the images, but it would be interesting to see what the apeture of the camera is in the mystery picture as compared to the other two.

Anyhow. There's my theory. Maybe that's it?

[Guest]

I overlaid the three photos and noticed that between the 2nd and 3rd picture (the strike and right after), there are two people in the lower left side of the photo that turned towards the light post (one is near the rocks about a 1/4" from the trees, and the other is on a park bench. You can see the one figure on beach turn at the time of impact and the one on the park bench is turned towards the light post after the impact. That would imply that it created enough noise to catch someone's attention.

As for the shadow, if it was a meteor, it could be a caused by the compression wave of the meteor as it passes thru the air. The air gets compressed, which increases it's density, which makes light bend differently/travel more slowly thru the column of compressed atmosphere. The shockwave, if it was close enough to the lamp post, could have easily blown out the bulb.

[C D Pace]

Shadow of jet aircraft vapor trail on lower area of clouds.

[Candiru Fish]

First they attack a lamp post, tomorrow it will be grandma! We must mount a counter attack immediately!

OK seriously, we can eliminate the "flash from the dying light" theory, since the flash would have to be INCREDIBLY bright, illluminating the entire sky, so that the shadow is offset (lack of brightness--the definition of a shadow). Also the shadow would carry all the way to the edge of the frame. It does not.

We can eliminate contrail shadow due to the position of the sun. (The sun has to be behind the contrail to cast the shadow downward.

We can elimnate lightening, the line is too straight.

The fact that the line does NOT carry all the way to the edge of the photo leaves out the possibility of sun flash etc. In fact it says its not a shadow of ANY kind.

We can elimnate a bug, too straight, too fast. (even a flying rod doesn't fly in a straight line...wait are flying rods REAL?)

We can eliminate particle beams, lasers, and pyschic mind waves as silly.

We can NOT eliminate a faked picture (and the timestamps being what they are makes this a distinct posibility, and yes it would have to be a good fake, but it wouldn't be the first time)

And we can NOT eliminate some sort of metor/space debris explination.

Nor can we eliminate the possibility that this is the evidence Mulder needed!

[Freddie4x4]

Looks to me that the light burst, just when the picture was snapped -- you can see what appears to be smoke and a very bright light -- the "line" in question clearly originates from this location. My guess is because the light was so bright, you got a purple chromatic aberration -- this is very VERY common when photographing bright objects with a digital camera..

At least thats what I think

[Ken_g6]

The top of the light pole does appear to change from the before image to the after image.

The problem with the exploding light theory I see is that the light cover should have blocked any light going up from the bulb in all directions. I could be wrong, but the light appears to be a "shoebox" type that would block just about anything.

Maybe the object just to the lower right of the lamp is a person with a gun shooting at the light. The bullet goes through the bulb, breaking it but not causing a visible explosion, and continues until it lodges in the lamp cover. The kinetic energy of the bullet sends the lamp cover flying in the same direction.

Meanwhile, the sodium vapor was shooting out the first hole left by the bullet. Even sodium blocks explode on contact with water, so sodium vapor contacting water vapor in the air should burn very rapidly or explode. This causes the flash while the flying lamp cover, now some distance from the bulb, creates a narrow shadow in the air.

Sodium burns with about the color of the explosion, while sodium oxide is white like the powder to the lower right.

Still, the bug looks more plausible to me.

[Rob]

I believe this is a shadow from the light bulb exploding on the right side of the pole. The pole fixture design is blocking the light from dispersing out to the left, creating a shadow, which only the camera could pick up at that instant.

[overtoke]

We have all seen pictures of the sun setting behind a tall mountain with a shadow (a streak) in the foreground stretching across the sky.

Is there a possibility that sunlight reflected off the water is a just the right angle to cast a shadow from the bottom up?

[Guest]

that the overall time from pic 1 to pic 3 is 45 sec. Contrails would have to be moving quite quickly for it to only be in one photo, or any other shadow producing object. Not saying that it's impossible, just unlikely.

[?]

WHAT STREAK?

[Dr. Z]

Best Guess: (A bit strange!)

Serendipitous witnessing of a model rocket launch (or other projectile) from the dock, or more likely from the water, given the angle, followed by a chase vessel! The dark path is probably the smoke trail, with the picture snapped just after launch, the flame still visible. I interpret this was a projectile launched at an angle, into the clouds. It was very fortuitous to have snapped the picture at the near-instant of launch.

Observations:

Perfectly linear trajectory, dark path compared with background.
Bright, glowing (?flame?) at radiant of origin, with suggestion of white smoke in a serpentine pattern nearby).
Too coherent to be a shadow (shadow should diverge over distance)
Isolated crepuscular ray should be brighter, not darker.
Contrail shadow would have probably revealed a contrail as well.

Cool!

Dr. "Z"
University of Pennsylvania School of Medicine

[Guest]

1) This can not be a bug. That is just silly. Get a copy of the full picture and look at how small this "bug" would need to be. It would have to be VERY close to the lens to make the trail that long in 1/20th of a second and would have to be impossibly small to create the thin shadow line and the pinpoint flash on the picture. A gnat going Mach 10 couldn't do this.

Let's see, a bug going 1 m/s would cover 5 cm in 1/20 s. To cover that much distance in the picture, let's say it would have to be 10 cm in front of the lens. And it might have been very small. The wind blew from the right and behind I think, so it could easily have been carried on the wind. No need for the gnat to be going supersonic.

- Harald Hanche-Olsen <hanche@math.ntnu.no>

[MCarr]

Regarding the December 7 Astronomy Picture Of The Day, I get a similar effect with a thin sliver of bamboo skewer held in front of the lens of my camera. Assuming no hoax, I am wondering if the photographer's head was near the camera and if he has longish hair. Perhaps a hair, still attached to the photographer's head, touched the lens at the moment of exposure and a static discharge resulted at the point of contact, causing the flash and the smoky effect, which was not actually smoke, but glare or additional sparking during the 1/19th second exposure. The smoke effect does seems to snake around the flash point. In this case, of course, the position of the lamppost would be accidental.

[bev@gwion.demon.co.uk]

Is it possible this is a remnant of a vehicle entry trail? The linear continuity might indicate a controlled or missile trajectory where short distance. If it was say a massive ice/hailstone creating a vapour path as shot to earth by thunderous weather?

Look forward to learning more. Great website.

Bev

[skotay]

It look's like an insect flying past the lens.

[Guest]

it could easily be a bug. do the math. Even if the lens was 90 mm (does anyone know what size lens he had?) if it was say, flying 6 inches in front of the lens, it would only have to be traveling like .05 m/s to cover that distance in 1/20 of a second. 1/20 is actually a really long exposure. The brightness could be the flash off of the bug. This seems the most plausible.

[death555808]

The line is to straight and precise for this to not be digitally modified.
The coloring the the photo is not eithier.

[convivialdingo]

>>We can elimnate a bug, too straight, too fast. (even a flying rod doesn't fly in a straight line...wait are flying rods REAL?)

What if the bug was inches in front of the camera? With the flash on (which it seems it was), then I would think this is the most plausible explanation. Bugs can reach speeds of 30+ mph.

>>We can NOT eliminate a faked picture (and the timestamps being what they are makes this a distinct posibility, and yes it would have to be a good fake, but it wouldn't be the first time)

Possibly

>>And we can NOT eliminate some sort of metor/space debris explination.

Maybe it's the Mars Beagle returning!!!!

convivialdingo

[Guest]

i have no clue whut it is but i think the guy in the boat (right of the flash) could have sumthing to say it could be sumthing wrong with the camera or who knows howmany other things but i don't think its e.t. soyeah there is my two cents spend it how you see fit

[sensei]

I can't come up with any theory, but I have suggestion that might have helped in this case:

Why not use two syncronized cameras a small distance apart, then you could for exemple cretate stereo photos, from which you would be able to measure distence i three dimentions. You would also be able to rule out insects flying by, hair/dust on the lens and much more.

[Kevin in Vegas]

I believe this to be what I call a "Planar Contrail Shadow". Many of the other postings have mentioned it. If there is a long straight contrail, the shadow created forms a plane. If you are standing in that plane (directly in line with the sun and the contrail) you can look down the direction of the contrail along the shadow and see a dark line. I've seen them several times, but many conditions have to be just right: 1) No wind at contrail elevation, 2) Correct temperature and humidity for a long, non-dissipating contrail, and 3) You must be standing in the right location.

In this particular picture, there must be an opening in the clouds to the photographers left.

[slammy102]

I saw this numerous times when I was living in canada - I looked at the closely, and it seemed that they were on flight paths. I watched numerous planes going along these strange streaks.

[Kevin in Vegas]

I forgot to address the flash in my previous posting, although I don't think it requires much thought. It's at the elevation of the other streetlights, so it could be a light, or it could be the reflection of the sun off something shiny (even diffused sunlight can reflect). In my opinion, the shadow and the flash are unrelated.

[Guest]

The first thing I note about the dark line is that it is straight and fuzzy. If the line were vertical it would be similar to having something suspended directly in front of the camera. I suspect that this may have been an insect suspended from a line - ie a spider.The lack of damage of any kind to the apparent target, and the fact that the dark line and the flash appear in the foreground indicate that it was closer.

Also I noted that the order ot the photos was wrong, that the "before" shot is actually the last shot of the sequence, and that the "after" shot is the first. I would probably go for a more probable explanation - such as a insect in the foreground before accepting atmospheric explanations.