The complexity of our silicon technology, combined with silicon’s chemical similarity to carbon, have led people to consider if life were possible on a silicon backbone. It’s not the job of Theoretical Objects to declare something impossible, but big problems lie ahead. So let’s begin:
1) aerobic respiration
inhaling oxygen and exhaling carbon dioxide, the staple of carbon life beyond anaerobic bacteria, is impossible because silicon dioxide, is a solid (glass). Simply put, silicon life forms wouldn’t breathe.
2) selective permeability
one of the key features of life is a cell’s ability to maintain an environment different from outside conditions. This means they need selectively permeable membranes. Carbon based life uses a bilipid layer (two layers of fats) to accomplish this. Silicon to silicon bonds are not stable enough to form these long strings of fats. Some new chemical would be required.
Any complex life form needs to create complex molecules, and there’s no better way to accomplish this than polymers: long strings of repeated units. Silicon is capable of forming these polymers and with great variety, however these compounds (call silicones) are stablized by bonds to carbon and oxygen. Not exactly a silicon skeleton.
4) genetic instructions
If silicones might be the structure of silicon cells, there would need to be some method of coordinating the creation of these structures. DNA, is out as a canditate as it has a great deal of carbon base. Like DNA these instructions would be a highly stable chemical (the cell couldn’t survive otherwise) that is relatively easy to use by the members of a cell.
The search for a primary silicon based ecosystem is rather remote, even in the vastness of the galaxy. But amidst man’s fears of his own creations is an artifiicial life form worth considering: the robot.