[meteorite-list] Ram pressure question

From: Jeff Kuyken <info_at_meteoritecentral.com>
Date: Wed, 24 Nov 2010 19:51:45 +1100
Message-ID: <EC0116A9116F49E6BAFA7C482DA40B01_at_JeffPC>

Hi Patrick,

This may help:

http://www.meteorites.com.au/odds&ends/myths.html

Cheers,

Jeff


----- Original Message -----
From: "Patrick Wiggins" <paw at wirelessbeehive.com>
To: <meteorite-list at meteoritecentral.com>
Sent: Wednesday, November 24, 2010 3:04 PM
Subject: [meteorite-list] Ram pressure question


> Hi all,
>
> Could someone please explain what "ram pressure" is?
>
> Has it got something to do with when air is compressed it heats up so when
> a meteor passes through the atmosphere it compresses the air in front of
> it causing the air's temperature to rise and it's that heat that ablates
> all but the very small meteors?
>
> Many thanks,
>
> patrick
> N Utah USA
>
> On 23 Nov 2010, at 15:03, Chris Peterson wrote:
>
>> Heating is due to ram pressure for bodies larger than a few millimeters.
>> For very small particles, ram pressure is not a factor because of the
>> large distance between air molecules compared with the cross-sectional
>> area. These small particles do heat up as the result of collisions with
>> molecules, in a process that is analogous to friction.
>>
>> In other words, for all bodies that produce meteorites, frictional
>> heating effects are insignificant.
>>
>> Chris
>>
>> *****************************************
>> Chris L Peterson
>> Cloudbait Observatory
>> http://www.cloudbait.com
>>
>>
>> ----- Original Message ----- From: "JoshuaTreeMuseum"
>> <joshuatreemuseum at embarqmail.com>
>> To: <meteorite-list at meteoritecentral.com>
>> Sent: Tuesday, November 23, 2010 2:22 PM
>> Subject: [meteorite-list] Temperature of meteorites
>>
>>
>>> I was under the impression that it's a myth that direct friction from O
>>> and N molecules on the surface of a meteorite create the heat that
>>> causes ablation. I thought that ram pressure in front of the meteorite
>>> was the main factor in generating heat. The KE and PE would create a hot
>>> shock layer which would flow back around the meteorite causing its outer
>>> layer to melt. I would think that friction is a minor factor, unless
>>> you're talking about ram pressure as a kind of friction.
>>>
>>> Phil Whitmer
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Received on Wed 24 Nov 2010 03:51:45 AM PST