If you happen to come across any live silicone-blobs from this or another world, kindly let me know
"Directed Evolution" and Alien Life
All life forms (on earth) rely on carbon (chemical symbol "C") for their existence and functioning. From miniscule bacteria to giant sequoia trees, from worms to whales, no life on earth including humans would exist without "carbon" in various combinations with other elements, most notably hydrogen, oxygen, nitrogen, and phosphorus.
Recent news speculate about
hypothetical types of biochemistry and extraterrestrial life forms using a "silicon" based system, possibly akin to the
Caltech artist's rendering of such an envisioned life form shown nearby:
It may be difficult to figure out what's front or back on that but it's a lovely alien creature, isn't it?
Another headline says "
Scientists shocked by discovery relating to alien life" and "the search for alien life may have been altered forever by an amazing new conclusion by researchers."
Researchers say in a new paper published in the journal
Science that silicon can be made to bond naturally with carbon, which could open the door for many possibilities, not just with regards to alien life but also for human engineering. They term that process "directed evolution."
Is the idea of "evolutionary tinkering" based on the claim that "silicon can form long chains of molecules, making it a potential building block for life" realistic or based on false assumptions? In order to evaluate that, one needs to look at the actual chemistry which I will try to explain in brief.
Chemistry in-brief
The element
silicium (the actual, though now possibly obsolete, name for the element is "silicium" with the chemical symbol "Si") is in the same group as carbon in the Periodic System of elements, actually right below carbon in that column of Group IV elements. Silicium, commonly known as "silicon," (but not to be equated with silicon
e(s) or silicates), like the element C, prefers to be attached with chemical bonds to four other atoms. Combinations with oxygen (chemical symbol "O") are most common in nature. Such Si-O compounds form much of the earth's crust, known as lithosphere, in the form of "silicates", i.e. compounds with four Si-O bonds. Sand, mostly the mineral "quartz" is a prime example as it only contains Si and O, chemically SiO2. It really is a three-dimensional structure of one Si atom bound to four oxygen atoms, each of which is bound to another Si atom.
In contrast to chemical structures with chains of carbon atoms directly bound to other carbon atoms that are present in all life forms on earth, there are no natural compounds with direct Si-to-Si bonds on earth.
To sum up, the idea that "silicon [silicium] can form long chains of molecules, making it a potential building block for life" or of "silicium-based life forms" is suffering from a certain lack of knowledge and understanding of the chemistry involved.
Are there real "silicon
e"-type compounds on earth? Yes of course. However, they do not have Si-Si bonds; they are manmade materials prepared under special conditions for the synthesis.
Silicon Compounds on Earth
Modern chemistry has been able to create many substances that are not found in nature. Silicon
e- type compounds are among them. Quite likely, you'll have used some such silicones already, for example in common caulking materials (not all of such) that withstand the ravages of nature, i.e. the influence of light and water, for a long time. Kept from contact with air and moisture, such caulking materials can be stored for a long time and only polymerize to insoluble but still flexible substances on exposure to air. Therefore, they are widely used to patch cracks in walls, to
seal out water and air. Silicone oils are widely used as lubricants, hydraulic fluids, dielectrics, and heat exchanger fluids. Other uses of silicones are "rain-away" windshield treatments for cars, "
silly putty," bouncy balls, and various other toys and items.All such silicone-type materials have chains of "O-Si-O" (same as in quartz) plus some actual Si-C bonds and, simply for the lack of life forms that can "digest" such, are quite stable under natural conditions. The combination of both O-Si-O backbones with actual Si-C bonds gives them flexibility and durability as well as their water-repelling property.
These silicone-type materials are useful in many ways (or fun to play with). The caulking stuff certainly likes to stick to and become inseparable from any textile in short order. So, don't use your "Sunday-Best" when working with them.
However, the thought that these types of compounds could be the backbones of extraterrestrial forms of life in the universe, that by all other facts known is based on the same chemical elements and the same chemistry as known on earth, does appear a bit far-fetched. It goes well with other recent claims like the discovery of purportedly "
alien structures" on the moon.
If you happen to come across any live silicone-blobs from this or another world, kindly let me know.
Dr. Klaus L.E. Kaiser -- Bio and
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Dr. Klaus L.E. Kaiser is author of CONVENIENT MYTHS, the green revolution – perceptions, politics, and facts Convenient Myths
