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Asked by SodiumHypobromite to John, Laura, Luke, Rob, Ruth on 16 Jun 2016.
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Luke Williams answered on 16 Jun 2016:
Yes I do. Such a big thing in science fiction, from what I know about the topic, there is no “show stopper” in this regard. The relative stability of silanes may be an issue though.
What I think though is that any silicon based lifeform may not necessarily be analogous to a carbon based one – just because silicon looks like it might be able to replace carbon doesn’t mean that a silicon lifeform would have to use all the same things but in silicon form.
I suppose one aim of synthetic biology or astrobiology might be to create some sort of bacteria based on silicon, but I haven’t a clue where you’d start with making silicon based DNA etc, and how you would be able to create all the enzymes necessary for life using silicon.
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Ruth Patchett answered on 16 Jun 2016:
Great question! Perhaps not on Earth where as you know most known life forms are carbon based. But as Si belongs below C in the periodic table so they have a lot of similar properties so it is possible the conditions on another planet favour lifeforms made up of Si based compounds instead of carbon. There are some big differences though too, for example when we make energy in our bodies we breathe out carbon dioxide but the same reaction with silica would result in a solid byproduct that couldn’t breathed out in the same way. So possible but the life-form would be quite different from how we know it on earth.
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Laura Finney answered on 16 Jun 2016:
There is a theory that life outside the earth may be silicon based rather than carbon based (like us) so yes maybe!
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John Fossey answered on 16 Jun 2016:
This often comes up in sci fi, feasible but only more probably under different boundary conditions.
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Robert Williams answered on 16 Jun 2016:
Silicon bonds ina different way to carbon.
Silicon prefers atoms such as Oxygen to make 4 bonds with – that’s why most rocks are silicates and are ‘hard’
Carbonate rocks are gnerally differrent though Marble is an exception.
So its a bigger challenge for silicon to form similar compounds such as amino acids that carbon forms ‘easily’.
For the same reason carbon forms hydrocarbons readily whereas the only similar compiund that silcon forms is Silane which is the silicon requivalent to methane.
As far as I know Silethane – i.e. Si2H6 does not exist and neither does Silibenzene – i.e. Si6H6.
Having said that if the conditions were right on an ‘alien planet’ then silcon based lifeforms might be possible
Comments
SodiumHypobromite commented on :
Thank you! As a further question which Robert posted, Why is it that Si2H6 and Si6H6 cannot form? Is it because they are so unstable?
Luke commented on :
I think that longer silanes do form (not sure about silibenzene), but not hugely long ones. They tend to be too unstable once they form and spontaneously break down.
It would likely require more specialised conditions than those for carbon based life to form, I think I saw something about sulphuric acid rich conditions. Another option is to have silicon-oxygen based long chains, which have more stability.
I think the bottom line is that silicon is an option, but likely to be much more limited in scope and location than carbon life.
Does make me wonder what else life could use.