Starship Asterisk*

'scuse me ... only one twisted "meteor." Didn't realize it was an inlay photo.

Why do most people assume that all meteors are spheres? It seems to me that the more reasonable question about meteors should be "What is the distribution of shapes meteors have upon entering the atmosphere, given that there are NO perfect spheres?"

The follow up question is this. How eccentric does the shape have to be to create tangential forces great enough to divert the path? I agree with the ablation theory as well. As the meteor burns, the irregular side can melt down - eventually making the meteor a more (but not entirely) perfect sphere.

It's the same meteor streak magnified.

I can't see any effect in the star images either. I'd expect even a faint line across each star if it were camera shake.

As an aerodynamicist working with (Non military) CFD codes for supersonic flows, I'm quite happy that this is aerodynamic.

Many shapes could be stable and yet rotate like this.

I take a lot of astrophotos and I'm with those who think it's camera shake. The clincher to me is the symmetrical "wings" on the star images, which actually, on the brighter stars, look oval. These would be caused by a brief rotatory camera shake at the start of the exposure, which decays to steadiness at the end. This would give precisely the effect we see on the moving object (the meteor) - the unsteadiness resulting in a sine wave effect at the beginning which decays to a straight line towards the end of the exposure.

Looking at the photo again I can see what you mean. The larger stars do have a faint arc shaped smudge.
In this case it probably is camera shake, but I reckon a spiral trajectory is possible in some meteor cases.

A shape that creates lift and is slightly twisted so it rotates relatively slowly will do it.

The photos to look at for evidence would be those that capture a meteor break up. All the bits will be asymmetric before ablation smooths them out.
Most will be unstable and tumble, following a straight path, but occasionally some may be stable and yet asymmetric enough to show this effect.

Could It be a small tremor of some kind made the camera shake? A lot of things can make the ground quiver a bit and it doesn't look like the camera would have moved a whole lot.

If the meteor is traveling at thousands of miles per second, is it physically possible for something the size of a grain of sand or small rock to make such large and rapid oscillations in the short period of time that it is visible?

Sorry, correction ... thousands of miles per hour.

The wavy meteor and it's background stars are duplicated on a smaller scale on the right of the picture. FAKE.

I'm stuck between the camera/tripod motion and the knuckle-ball theories. The second streak ahead of the meteor image shows the same twisted pattern which supports the camera motion side and yet, the twist appears to increase in amplitude toward the "tail" end of the tail. That could be due to some sort of lift effect similar to wing vorticies produced by aircraft in flight. A single bump or large rick sticking out of one side could cause the meteor to spin up as it entered the atmosphere if it weren't already spinning before re-entry.

JLo wrote:Two "meteor trails," both with the same spiral twist, appear in the photo. This would tend to rule out a rotating meteor since they are relatively uncommon; but the 2nd one looks so much like the 1st that it may be an aberration, maybe caused by the lens ...

Um, the inset in the upper left is a magnification of the portion of the image on the right which contains the meteor trail.

tetrodehead wrote:The wavy meteor and it's background stars are duplicated on a smaller scale on the right of the picture. FAKE.

Eukonidor wrote:Um, the inset in the upper left is a magnification of the portion of the image on the right which contains the meteor trail.

As Eukonidor points out, the duplicate is in the upper left, not the lower right, and is not a reason to shout "FAKE"

I think it is just camera wobble. You can see the effect of that in the brighter stars also - they have tiny vertical streaks above and below.

Sorry for my fake statement. My monitor, like me, is past it's prime.

Note that it is only in the queue, the phenomenon should be atmospheric. Atención que es en la cola, el fenómeno debe ser atmosférico.

Considering the shape of some brighter stars, this object may have been distorted by the window/dome. Is it optical grade? If not distortion, returning space junk seems a good bet.

Notice the slight wobble in the track farther to the right? Notice that nothing is terribly sharp - that all the light sources in the image have a slight amount of blur? This is camera wobble, pure and simple. In an image with no wobble, the various light sources would either be clear or clear streaks.

1) If it is as quick as most meteors a camera shake would blur the entire picture.

2) I use a sling shot and rail road gravel to get the geese off my garden and my pond. Railroad gravel is dark basaltic stone crushed and angular (use for my driveway cover) launching this thru the medium of the lower atmosphere, cause the rocks to spin and tumble. I imagine that a rock of like angularity would react to the atmospere high up the same way.

3) We have estimated speed. We have the rotational pitch (4 or five visible rotations). If we have the formulas we can fine the pitch angle of the entry edge to the meteor and since it holds that edge thru so many rotations, sermise it is probably a metalic or very hard rock.

4) Asymetric center of gravity may cause the same action but I don't think as many rotations.

Regardless it is a neat picture.

T

Sorry for a naive question: is it possible there are two meteors involved?

Perhaps the twisted trail is due to some spin associated with the meteor... Or maybe turbulence in the upper atmosphere.

JLo, exSquid: the "second meteor" is an enlarged inset image of the first (there is only one meteor), and the camera is on a clock drive, which tracks the moving stars.

the useful point of information would be to calculate the spatial variance implied by the "wobble". an eyeball guess from a uranometria star chart suggests this is about 1/3 degree. if the meteor is about 30 kilometers up (for example), then the wobble would appear to be about 200 meters on either side of the average path. double the assumed height and you double the wobble, but given an object of the right shape, that amount of skitter seems entirely possible to me.

the idea that animals or ghosts have "bumped" the camera seems feeble. presumably, by the time you have nighttime access to an observatory like tenerife, you know how to run your astrophotographic set up.

There have been discussions about the image, of course. Certainly, all what is possible may have happened. I can definitively exclude that an animal was in the vicinity of the camera as there are none in the surroundings of the telescope buildings. The areas around the solar telescopes are covered with white quartz sand... Wind may be an option, but the tripod is just 20 cm above the ground and I took numerous (straight) trail images even under strong wind conditions at the same place. As I said, it cannot be excluded by 100%, but is at least very unlikely.
Today, Jeremie Vaubaillon mailed: "It reminded me of one meteor that I took a picture of in January 2008: http://antwrp.gsfc.nasa.gov/apod/ap080107.html
At the time, I thought that the weird shape of the meteor was caused by the vibration of the plane. Today with your image, I am not sure anymore."
Unfortunately, other cameras were not operational this night: at LaPalma, where the event must have been almost overhead, the cameras were not switched on due to works on the buildings. Another all sky camera located at the STELLA telescopes at Tenerife was just changed and not in regular operation this night. So, still neither a confirmation nor an conclusive explanation.
Juergen Rendtel

I've seen many of these in the last three months of 24 hour radio observations. Being in OKC, I am lucky to get strong scatter from the Space Radar in Kickapoo. Many "mainbeam" meteors exhibit defined "tendrils" in the spectral plot, either from rotating jets or periodic off-shoots in it's trajectory. Linked below are a couple of those I have posted in FB.

http://www.facebook.com/album.php?aid=2 ... 2b57bfd4fb

http://www.facebook.com/album.php?aid=2 ... eb1b8d693a

Here's an excellent example of multiple spectral "spikes". Each representing ion trains of different velocity vectors WRT to the transmitter/receiver angles.

http://www.facebook.com/photo.php?pid=3 ... 1122357299

Chris Peterson wrote:This image has been widely discussed in the meteoritics community. The consensus (unanimous as far as I've seen) is that the camera got jarred by wind or maybe an animal. The same effect has been seen on other images where that happened.

That doesn't jive with larger bolides pretty much all observers have seen at one time or another in which such a "spiral" trail continues to expand with the same shape. Unless I was in the middle of a eye seizure, the resulting persistant trail shape supported that it was most likely rotating at a high angular velocity and burning asymetrically.