Re: Can anyone explain this to a layman please?

From: Androcles (dummy_at_dummy.net)
Date: 01/01/05 

Date: Sat, 01 Jan 2005 16:38:02 GMT

"Edward Green" <spamspamspam3@netzero.com> wrote in message
news:1104595481.024372.211520@c13g2000cwb.googlegroups.com...
> 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. ;-)

Ever see an astronaut playing games drinking water while in freefall?
The globules float around wobbling and he then dives after them
and ...slurp... in they go.
But wait... Why are they globules and not cold steam?
Of course if we hung them on a washing line outside the orbiter
to dry they might become cold steam, and let us not forget our
good friend Boyle and his law about pressure and temperature
and volume, but I still can't help wondering why a cloud of
supercooled gas isn't a supercooled solid, especially with a
volume of (4/3) pi (1/2 ly)^3. It should mass as much as
an asteroid, at least. Oh well, just a thought. Like the man said,
"It is not known exactly how molecular clouds like Barnard 68
form".
Take me out of the gene pool, I already have grandchildren.
Androcles.