APOD 'Meteor Wiggling'

Comments and questions about the APOD on the main view screen.
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GoatGuy
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APOD 'Meteor Wiggling'

Post by GoatGuy » Wed Feb 02, 2005 5:45 pm

In an email I sent to the moderator, I questioned whether the 'wiggle' in the apparant motion of the APOD meteor was a result of a high-frequency vibration in the camera-system, and also whether a walnut-sized meteor is going to even move in a cycloid enough [say 1 foot?] to be visible 25 to 50 kilometers away.

Per below:
______________________

Sirs,

I couldn't help but note that the distant stars are oblate -- to the same amplitude as the meteor's supposed wobble. Digging deeper, the meteor's path has a decidedly sharp lower-to-uppper transition, and a relaxed upper-to-lower path. The slant of the stars though coincides with this: were the camera to be vibrating say at 60 hertz due to a motor drive?, or at some other high frequency due to a worn worm, then it would have modulated the apparant path in JUST THIS WAY.

Finally, just to confound the 'wobbling meteor' theory, the size of most "shooting stars" (most of which are certainly bright enough to be caught on camera as per this example) are said to be pea-to-walnut sized. Yet they are also said to be 25 to 40 miles up in the atmosphere. Even if the most aspherical chunk were to wibble on the greatest spiral (about a foot?) would a foot of radial deviation-from-straight even be visible 25 miles away? I think not.

GoatGuy
Armchair Physicist - UCBerk.
Alameda, CA U.S.A.
GoatGuy -- Because discussion is awesome especially when debating facts...

Dan Cordell
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Post by Dan Cordell » Thu Feb 03, 2005 2:02 am

Rather than answering it via email, I'll answer it here.

No, it could not have been camera jitter. While camera jitter can cause similar effects, a meteor's streak lasts (at most) a second, and usually not that long. Also notice that the background stars are not blurred like that--had the camera been vibrating, the star blur would have been significantly larger.

APOD's explaination is correct. As per some research done in the past few months by S. Tilvi (and to a limited extent, myself), many meteors are not made of uniform material, but rather dense chunks held together by less dense material. It is this non-uniformity, along with in-space collisions, that cause many meteors to be in strange shapes.

If a non-spherical meteor hits the atmosphere spinning, it can cause an effect like this. Most are not as noticable, this is a particularly impressive event. Which, of course, is why it made it to APOD.
Dan Cordell, Giant Space Cow

billyhill
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Post by billyhill » Sat Feb 05, 2005 2:53 am

I felt that I needed to reply to this. While imaging a Lunar eclipse in the late 90's one (only one) of my 35mm frames registered a strange red twisting thing. I contacted people off and on for years as to what this could be. The 35mm negative was inspected and all I got back was " cool or light blead but imaged". The twisting meteor(?) made sence after seeing the image on APOD. Look at this image as if one were coming more or less towards the camera and doing a burn. I don't know but seems to fit. The two links are to this original scanned imagenegative with no processing and a second cropped image showing only the red twist with a little color added. I was using a 10" LX200SCT at f 6.3 and a 35mm camera at prime focus.
Thanks

http://fototime.com/8749CA7C5240FEB/orig.jpg

http://fototime.com/AF39BC507CC2874/orig.jpg

Dan Cordell
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Posts: 99
Joined: Mon Jul 26, 2004 8:55 pm
Location: Michigan Tech

Post by Dan Cordell » Sun Feb 06, 2005 5:29 am

billyhill wrote:I felt that I needed to reply to this. While imaging a Lunar eclipse in the late 90's one (only one) of my 35mm frames registered a strange red twisting thing. I contacted people off and on for years as to what this could be. The 35mm negative was inspected and all I got back was " cool or light blead but imaged". The twisting meteor(?) made sence after seeing the image on APOD. Look at this image as if one were coming more or less towards the camera and doing a burn. I don't know but seems to fit. The two links are to this original scanned imagenegative with no processing and a second cropped image showing only the red twist with a little color added. I was using a 10" LX200SCT at f 6.3 and a 35mm camera at prime focus.
Thanks

http://fototime.com/8749CA7C5240FEB/orig.jpg

http://fototime.com/AF39BC507CC2874/orig.jpg
Yep, looks as though you may have been lucky enough to catch a head-on meteor.
Dan Cordell, Giant Space Cow

babygurl_4meaniedaddy
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Post by babygurl_4meaniedaddy » Fri Feb 25, 2005 9:37 am

this can be solved with differential equations and perturbation. They are studying it intensely and find that these orbits that "wobble" are actually an affectof chaos - a branch of mathematics that deals with sequences that have been iterated so much that they become random or chaotic. It happens over time with everything.
looking for a daddy to show me the stars