Perlan project - high wave flights

[Bill Daniels]

I wonder if these guys have fireproof flying suits.

See: http://www.sciencedaily.com/releases/2005/10/051018075220.htm

Quote from article:

"Previous observations near the Andes Mountains in Peru had found that the
atmosphere directly above some peaks was approximately 100 Kelvin [100
degrees Celsius; 200 degrees Fahrenheit] hotter than in nearby regions and
that the difference occasionally reached as much as 400 Kelvin [400 degrees
Celsius; 700 degrees Fahrenheit]. "

Bill Daniels

[Francisco De Almeida]

Quite interesting, but I do not think the article leads to such =
conclusion. Think about it: several types of aircraft have been flying =
very high above mountain peaks in the last half century without bursting =
into flames.

If you go still higher, temperatures rise naturally up to about 800 =
Kelvin in the Thermosphere. You run no risk of burning, though: the air =
density by then is so low that any heat gained from collision with air =
molecules cannot even offset the heat lost to outer space through =
radiation. The (accoustically generated) temperature spikes theorised in =
the article are therefore not so exceptional when viewed in context.

I suppose the Perlan people need to be well dressed, indeed, but not =
against the heat.

F.A.

[Bill Daniels]

"Francisco De Almeida" > wrote in message
...
> Quite interesting, but I do not think the article leads to such =
> conclusion. Think about it: several types of aircraft have been flying =
> very high above mountain peaks in the last half century without bursting =
> into flames.
>
> If you go still higher, temperatures rise naturally up to about 800 =
> Kelvin in the Thermosphere. You run no risk of burning, though: the air =
> density by then is so low that any heat gained from collision with air =
> molecules cannot even offset the heat lost to outer space through =
> radiation. The (accoustically generated) temperature spikes theorised in =
> the article are therefore not so exceptional when viewed in context.
>
> I suppose the Perlan people need to be well dressed, indeed, but not =
> against the heat.
>
> F.A.
>
You're right, of course. My posting was just a bit tongue in cheek. The
first scan of the abstract didn't make clear that the temperature spikes
were in the thermosphere (150 Km or so above the stratosphere) but a more
careful reading of the body did.

What IS interesting is that a phenomenon with roots in orographic turbulence
reaches this far above the earth's surface.

Oh what we don't know!

Bill Daniels