Review: "Concrete Space Colonies"

Hi Lucio,

It depends on the glass and on what other elements are involved in its
manufacture apart from silicon. Am not an expert on this, but I do know
that making glass transparent does involve additional elements. The
Egyptians and Romans had only coloured glass until the Syrians
discovered that by adding certain other chemicals you could sometimes
get clear glass, and introduced this to them. Even then it was over a
1,000 years before the Venetians found out exactly what proportions of
the chemicals you had to add to always get clear glass. They managed to
keep this info secret for over a 100 years and made a fortune as a
result. Nowadays there are umpteen different kinds of glass made in many
different ways.

Best wishes, Andy.

"Dr. Omni" wrote:

> From: John Frazer
> To:
> Sent: Tuesday, March 27, 2001 12:47 AM
> Subject: [spacesettlers] Review: "Concrete Space Colonies"
>
> [snikt]
> > He took this farther into speculation, and mentioned that it may
> > be possible to make blocks of optical quality glass of equal
> > thickness, so the "windows" could in fact be an identical brick
> > unit, with no other means of blocking outside radiation needed.
> > He wrote wistfully of the unknown possibility of making the entire
> > colony hull out of optical glass, with no other shielding or window
> > considerations needed.
> >
> That's indeed *very* interesting. Does anyone know how transparent
> glass can
> be made? Is it possible for a block of glass 2 meters thick to be
> transparent (in some extent)? If so, glass could be a better
> alternative
> than water for shielded transparent surfaces, at least for near-Earth
> settlements. Silicon for making glass can be extracted both from lunar
> and
> NEA regolith, leaving water for more essential applications
> (agriculture,
> human use, etc). Also, while an water cell would simply evaporate if
> its
> glass or plastic container was hit by a meteoroid, leaving a "hole" in
> the
> habitat shielding (and possibly in its pressure hull), a glass plate
> perhaps
> would face the same meteoroid by simply going opaque or translucent
> and
> perhaps leaving some bigger internal cracks. Or am I overestimating
> the
> physical resistance of glass?
>
> [snikt]
> Lucio Coelho
>
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