Re: Blacker than Black

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To further complicate issues - waste heat disposal can be a bit of a
problem in space.  On Earth you have thermal conduction, convection and
radiation to all help get rid of waste heat, but in space all you've got
is
radiation.  If you want your spacecraft doing anything it will generate
waste heat - and it has to go somewhere otherwise your spacecraft will
just
get warmer and warmer.	Since it has to go into radiation you will have
to
present a bright thermal signature.

The first thing I thought when I saw the pictures of the material was
that
those tubes make really good black body cavities.   It turns out the
perfect emitter/absorber is a small cavity in a surface (perfect
absorber
because any light that enters will bounce around until absorbed/perfect
emitter is a little harder to explain - I finally found a good way to
present it in my modern physics class last year.)  It doesn't even
matter
if the material is reflective or not - the cavity will eventually absorb
the light.  Those little nanotube basically act as little cavities in
the
surface.  Pretty neat in my opinion, even if it isn't a magical stealth
material for spacecraft.

On Sat, Nov 12, 2011 at 5:05 PM, Richard Bell
<rlbell.nsuid@gmail.com>wrote:

>  Being all-angle stealthy in space is
> impossible and making yourself stealthy  to certain observers is hard
> enough.  If you intend to do more than hang in space, absent some kind
> of inertialess drive, stealth is impossible
>
>
>