[meteorite-list] Chelyabinsk: of contrails, bollides and IR

[Chris Peterson]

Meteoroids don't implode, they explode. That occurs at whatever point 
the stress they experience from the ram pressure on their forward face 
exceeds their material strength. There is nothing special about a height 
of 5 km; disruption can occur anywhere from 100 km high to the ground. 
In the vast majority of cases, the height of disruption is above 30 km, 
but the actual point depends on the total mass, composition, and 
structure of the meteoroid.

Chris

*******************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

On 2/16/2013 8:27 PM, E.P. Grondine wrote:
> Hello everyone -
>
> I got to watch the Russian videos before all the pop tunes and colorful Russian expressions were removed. The sanitized compilations are simply not as good. I would have preferred subtitles being added to them instead.
>
> One of the interesting things is that releases of binding forces, the bollides, or "implosions" have previously been estimated to occur around 5 kilometers in altitude. If I am viewing the entry contrail in this case correctly, it looks like this bollide went off around 8 kilometers in altitude, indicating a pretty friable small impactor.
>
> Given the slow velocities of the shattered glass pieces, what reached the ground was pretty small. You can be sure that after much delicate dancing, data will come out and analyzed by the specialists.
>
> In the meantime, infra-red spread estimates from the public videos may end up providing a first order estimate as to the magnitude of the bollide.
>
> Another interesting thing is that it has generally been assumed that almost all the momentum was converted into energy in the bollide, but in this case we can see contrails going off after the main bollide event.
>
> Xinhuanet is reporting Russian online sales:
> http://news.xinhuanet.com/english/world/2013-02/16/c_124351175.htm
>
> For you folks out there in the field, its -7, so be nice to people; you might need their help to stay alive. This area has high tech industries, so don't try to pull any stupid bs stunts either. Remember, the reputation of all meteorite hunters depend on everyone else's actions, so please don't p*ss in the soup.
>
> In closing, if this was a CC, and if larger pieces did continue onward, then it has implications for searching for fragments from other CC bollides, such as Tunguska.
>
> Finally, I saw one video where a very young lady was having a small piece of glass removed from her cheek; if she done not get at least a crumb of this one, shame on all of you.
>
> Good hunting, all
> E.P.