Re: Can anyone explain this to a layman please?

From: Edward Green (spamspamspam3_at_netzero.com)
Date: 01/01/05 

Date: 1 Jan 2005 08:04:41 -0800

Androcles wrote on the fly, with rapidity and fecundity far exceding my
own:

> Let's put the record straight. In astronomical terms a sphere of
radius
> 100 light years is not very large. Our own galaxy, the Milky Way, has
an
> approximate diameter of 100,000 light years, and although there are
> patches
> of dust obscuring the core, most of it can be seen.
> There are a small number of stars within such a small volume
> (I'm not going to dig out and name them all, but the nearest
> (other than the sun) is Proxima Centauri, about 3.8 light years away.
> If there were a nearby system and a screen capable of blocking
> ALL the energy from it, the screen would be known to us.
> Hold a penny at arm's length and you'll see why.

That was in effect my Superman's cake comment. Although I'm not sure I
follow the details of this particular argument, nor that I ought to.

> It would obscure
> radiation from much further away as well.
> Now, having said that, can we see the dust cloud?
> http://www.star.ucl.ac.uk/~apod/apod/ap041219.html
>
> "What used to be considered a hole in the sky is now known to
> astronomers as a dark molecular cloud. Here, a high concentration of
> dust and molecular gas absorb practically all the visible light
emitted
> from background stars. The eerily dark surroundings help make the
> interiors of molecular clouds some of the coldest and most isolated
> places in the universe. One of the most notable of these dark
absorption
> nebulae is a cloud toward the constellation Ophiuchus known as
Barnard
> 68, pictured above. That no stars are visible in the centre indicates

> that Barnard 68 is relatively nearby, with measurements placing it
about
>
> ****** 500 light-years *******
>
>
> away and
>
> *********half a light-year*******
>
> across. It is not known exactly how molecular clouds like Barnard 68

> form, but it is known that these clouds are themselves likely places
for
> new stars to form.
>
> *******It is possible to look right through the cloud in infrared
> light.******
>
> So clearly Uncle Arsehole is a fucking imbecile for suggesting that a
> dust cloud can obscure the entire EM signal of a star and its
planets,
> at say, 100 light years distant, and should be removed from the gene
> pool.

I am not sure if Uncle Al has not bred already, and if not, if he
should not be allowed to. It is possible that he may pass some of this
intelligence on to spawn, but not all the social deformation. Then
again, the same might be said of Charles Manson.

I filled in some of the gaps in Uncle's argument, so he can claim right
away that's what he meant, and won't have to backpedal.

Anyway, if we did have the local expertise and will to discuss this
question effectively, we might note that the obvious goal of the OP is
not really to block all energy emanating from a star from ever reaching
the Earth, but of blocking all intelligence of a civilization living
near that star from reaching the Earth. The question is not one of
blocking, but of camouflage. Perfect camouflage might be boring from a
literary standpoint; good camouflage but one ultimately creating
suspicion to human reason might be more interesting -- something
peculiarly anomolous but not immediately and obviously unnatural in
that segment of the night sky.

The opacity and reflectivity of dust clouds to the EM spectrum is
probably complicated, which is alluded to by Franz Heyman's
"sometimes", which is his abreviated way of saying what either of us
would take 2000 words for -- and you are evidently even a faster typist
than I are, even. ;-)