[meteorite-list] friction or ram pressure?

[Chris Peterson]

Your understanding is broadly correct, although I don't think "friction" 
is quite the right word to describe the heating process for particles 
smaller than about a centimeter. The mechanism of heating depends on the 
particle size and on the mean free path of atmospheric molecules (and 
therefore on height). For centimeter scale particles, most of the 
heating is the result of creating a compressed gas zone along the 
leading edge. For millimeter scale particles the heating involves 
collisional processes. Not surprisingly, there's an intermediate range 
where both processes are operating.

Chris

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

On 1/25/2014 7:54 AM, Francesco Moser wrote:
> Hi all!
> I have a question for you regarding falling stars and fireballs!
> Which is the physical process that heats a meteoroid during his travel through the atmosphere?
> Is the friction with the air molecules or the ram pressure of the shock wave in front of the meteoroid?
>
> I think, but maybe I'm wrong:
> for the smaller meteoroids like the one that generate the falling stars the main process is the friction, instead for the bigger meteoroid like the one that generate meteorite on the ground or for example for a Space Ship like the Space Shuttle the main process is the ram pressure ... I'm right?
>
> Thanks a lot!!!
>
> <x>x<x>x<x>
> Francesco