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Is the concept of transparent metals (like the transparent aluminum in Star Trek IV - Voyage Home) a real-life concept? Or is it far-fetched movie fiction?

Thus my main question then is: could we apply the concept of transparent metals to, say, a Mars colony; or the step before that, a moon colony? Using glass-like transparent metal that's far more rigid than true glass as the "dome" to cover the environment of the colony/base, thus providing astronauts/colonists with a large biome within which to move freely without a space suit?

Please bear with me as I'm new to this community, and wasn't sure if this was the right site to post this question to, so I apologize if not.

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    $\begingroup$ No, that's largely tied up in the definition of what a metal is ie a sea of free electrons which would absorb the light and re-radiate it. $\endgroup$ – Martin Beckett Sep 17 '18 at 17:42
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    $\begingroup$ Note: glass is far more 'rigid' than metal, the advantage of metal is that it isn't rigid, it will bend and deform under a load rather than instantly fail like glass. $\endgroup$ – Martin Beckett Sep 17 '18 at 17:42
  • $\begingroup$ Let me introduce you to Aluminium Oxynitride also know as ALON or Transparent Aluminum. $\endgroup$ – StephenG Sep 17 '18 at 22:04
  • $\begingroup$ @StephenG Both of your links state that this compound is a ceramic. Most ceramics contain metal atoms; it doesn't make them metals. $\endgroup$ – Chemomechanics Sep 18 '18 at 17:40
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The reason that metals are generally opaque (and, in fact reflect light) is that they have so many conduction electrons that their plasma frequency, which is proportional to the square root of the electron density, is very high and in the ultraviolet. Visible light is below this frequency, which is why you can't see through typical metals. But what about a metal which has so few conduction electrons that the plasma frequency drops down to somewhere in the visible light range? In that case, you would be able to see through the metal. Do such metals exist? Don't see any theoretical reason why they couldn't, and in fact indium tin oxide (ITO) seems to be an example of a transparent metal (transparent metal for displays).

HOWEVER, from your question it seems that your interest in transparent metals is related to the mechanical strength properties of metals rather than to the fact that metals conduct electricity. So you're really interested in transparent materials in which the atomic bonding is predominantly metallic (as opposed to ionic or covalent) than just transparent materials which happen to be electrically conductive. So indium tin oxide, which presumably has relatively few conduction electrons and not likely to have much metallic bonding character, is probably not what you're looking for.

You want a material which has so many conduction electrons that it has metallic bonding but yet so few conduction electrons that the plasma frequency is low enough to make it transparent. Not aware of the existence of any such material. Perhaps the best bet for a material that has the characteristics that you're looking for is some sort of "designer" or composite material in which there is a micro-scale skeleton lattice structure of high-strength metal to provide strength combined with some transparent material which makes the composite material at least partially transparent.

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  • $\begingroup$ If the strength is the relevant factor rather than being a metal, then I assume diamond would be a lovely dome material. $\endgroup$ – Anders Sandberg Sep 17 '18 at 19:15
  • $\begingroup$ @AndersSandberg Possibly, although diamond can shatter if you hit it. But at least it would be fairly scratch-resistant. OTOH, there is diamond and silicon carbide dust in space, but hopefully most of that stuff is so small it will just polish the dome rather than scratch it. $\endgroup$ – PM 2Ring Sep 17 '18 at 19:34
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    $\begingroup$ @AndersSandberg - Diamond has an extremely high compressive strength, but as I seem to recall it - like most brittle materials - is not particularly strong under tension. Also, as PM2Ring points out, it can shatter under impact so it probably doesn't have very high toughness compared to most engineering metals. $\endgroup$ – Samuel Weir Sep 17 '18 at 19:45
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About Metal Glasses :

There are serious research in Glasses made of Metal

https://www.zmescience.com/science/chemistry/metal-glass-about-howto-0423423/

The core ideia , from what I understood is that 'glass' is a kind of structure that is locally a crystal , in general, this make some space to light pass through easier if something don't capture the photons going through the material - what happens in metals very frequetly ; one easy way to understand this , with some 'approximation', is the kind of 'merged orbitals' of metals called bands whom make the life of some photons little troubled to enter in the metal.

I don't have read profoundly the articles, but I think that can be two things happening to easy the way through of the photons : or something like Franck Hertz experiment : https://www.wikiwand.com/en/Franck%E2%80%93Hertz_experiment or the graphene in the alloy 'traps' orbitals real closely to leave a 'room' for some traveling photons

Maybe some people whom works in that field can clarify for us the phenomena

A nice dome do build:

Very nice and imaginative question ! Besides the cost to build such alloy and the necessary engineering reaserch to make that great structure stable - what is not so easy and cheap - looks possible, and I hope the build this thing in our life time ! But we have so many barriers to surpass until we can afford that project ...

Some links like these tells you a bit about that :

https://www.wired.co.uk/article/getting-to-mars

https://www.quora.com/Why-can-astronauts-not-return-from-Mars

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  • $\begingroup$ Thanks for contributing this answer; please be sure to proofread it. It's not clear what "A nice dome do build" means. Nouns such as "glasses" and "metal" are typically not capitalized, and there's no space before a colon, exclamation mark, or ellipses. $\endgroup$ – Chemomechanics Sep 18 '18 at 17:36
  • $\begingroup$ Thanks for your feedback ! I will revise soon to make my text more clear, @Chemomechanics $\endgroup$ – 521124 Sep 19 '18 at 21:08

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