Archive for July, 2010

Silicon Based Lifeforms vs Creationists

July 23, 2010

Ever since the ground-breaking experiments of Urey and Miller, who proved it was possible for amino acids to spontaneously arise out of a laboratory-controlled “primordial soup” of inorganic chemicals, scientists have been racing to take the next step and find out just how the amino acids can become self-replicating organic strings. The importance of this is obvious. This would give us a continuous lineage from rocks to humans. Evolution in a nutshell, a complete package end-to-end with which to torment creationists.

Unfortunately, lacking this final detail in the string of continuity, mutation, and speciation, creationists will cling to this last vestige of their delusion like a drowning man rubbing a rabbit’s foot. Of course, they will do that anyway, even with absolute proof that evolution can stand on its own, and continue to perpetuate the lie that evolution is still grounded in Lamarkian concepts. Anyone who’s ever been on the receiving end of a Jehovah’s Witness tract knows just what I’m talking about – their sum total knowledge of evolution comes from the latest theories of the 1880s and the rants from their apparently uneducated pastors.

Even if scientists complete the experimental foundations of the RNA World, there will still remain skeptics who will blame the results on contamination from external sources, unless, of course, the carbon-based replicating organism is completely alien to anything that currently exists. But the odds of that are considered low; carbon compounds like to react with other carbon compounds in very specific ways that restrict the options available.

But why go this route? Why not select a version of life that can’t possibly be contaminated by Earthly life forms? For example, silicon (versus carbon) based life? Something that will provide incontrovertible proof that life can arise spontaneously in some of the nastiest conditions the universe can lob at us.

I’ve read a bit about the possibility of silicon-based life forms. Most people don’t think it’s possible, usually based on speculation about how silicon bonds with oxygen and can’t properly build long, strong chains like carbon does (not completely true – look up polysilanes). Most of these articles assume certain things; that oxygen, carbon, hydrogen and other low-level atoms are still going to be around for silicon to bond with, and that the temperature of the silicon-based chemistry will have to be about the same as our own. Silicon doesn’t do well at this temperature. Too hard, too short a chain, blah, blah, blah.

But to create a true silicon analog of the carbon based world, we have to eliminate the whole top line of the periodic chart (barring lithium – we need that). This might seem to be a crazy task until we look at Venus, which at a mere 600 degrees C, and with the aid of ultraviolet rays, has lost most of its hydrogen and oxygen into space. It has very little water left. However, for a silicon analog to exist, with no carbon, hydrogen, oxygen, nitrogen or helium to pollute its atmosphere, we would need a fairly small planet with a surface temperature of over 1000 degrees C. Taking a look at the next row down on our periodic charts, we can see that the analog to H20 would be Li2S, oceans of dilithium sulfide (not to be confused with dilithium crystals, which are used in starships). This happens to melt at about 950 degrees C. The second row in the chart below nitrogen is phosphorus. P2 gas forms from P4 at over 800 C, which works just great for us as our analog to N2 in our own atmosphere. An atmosphere consisting mostly of phosphorus might be hard on us humans, but it’d likely be just fine for the siliconites. The analog to C02 would be SiS2, silicon sulfide.

I’m not sure how silicon would do as a chain at 1100 degrees if it was isolated from lower-level chemical elements. Probably not as well, after all, you are dealing with a valence shell that’s one shell further away from the nucleus than carbon. But once you eliminate all these reactive impurities, who’s to say?

What I’d love to do is build a nicely insulated ceramic chamber, dump a lot of these second-level elements into it, heat it up to 2000 degrees to vent off the light elements, then let it cook for a few years around 1100 degrees. Make a “freezing side” of the box at 900 degrees, and a hot side at 1150 to give it a nice thermal gradient. Add a spark-gap generator. Then watch and see what grows. Repeat Urey and Miller’s 1-week experiment, but on silicon. Would we get analog-silicon amino acids? I’d bet on it. Analog RNA? Analog life? Who knows? But it would sure be cool to find out.