The ADELAIDEAN wrote:
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Life exploits whatever is available. Terrestrial life is mainly carbon based because carbon is readily available here.
However investigators have pointed to the possibility of live evolving elsewhere based on Silicone, or even Aluminium-based life where Carbon is not available readily enough. It's not as far fetched as one might think.
Here on Earth Silicone already plays a part in some life forms. Those very fine 'hairs' that protect some plants and break off as prickles in the skin when handled are actually glass, based on Silicone that plants have evolved to extract from the soil. And Aluminium is Earth's most abundant metal, so if our planet had not had such a ready supply of Carbon, evolving life might have turned to Aluminium instead for its organic base.
Life forms based differently from ours chemically would enjoy a mixture of advantages and disadvantages compared with Terrestrial life. At the very least it would be different enough to seem exotic to us. Such creatures might still use DNA, but made of different elements.
Therefore I doubt that our encounters with such life forms would lead to any shotgun weddings.:)
We probably have more silicon than carbon on our planet.
Life evolved around carbon because of its chemical properties.
Silicon is close to carbon in the periodic table but it has many important difference.
Oxygen is combined with carbon to generate energy. The waste product is carbon dioxide. CO2 is a gas and is soluble in water.
For a silicon life form, the waste product silicon dioxide is an insoluble solid, very hard to get rid of and difficult to recycle.
It is difficult to imagine any advanced silicon life form on a planet similar to earth.