There are a few reasons why life on Earth is made of carbon, not silicon.
Carbon is more versatile than silicon.
Carbon can form bonds with up to four other atoms, while silicon can only form bonds with up to four other atoms. This allows carbon to form a wider variety of molecules, including the complex molecules that are necessary for life.
*Carbon-based molecules are more stable than silicon-based molecules.
This is because carbon-carbon bonds are stronger than silicon-silicon bonds.
*Water is a good solvent for carbon-based molecules, but not for silicon-based molecules.
Water is essential for life on Earth, and it is also a good solvent for the molecules that are necessary for life. Silicon-based molecules do not dissolve well in water, which would make it difficult for them to function in a biological system.
Here is a more detailed explanation of each of these points:
Versatility:
Carbon can form bonds with a wide variety of atoms, including other carbon atoms. This allows carbon to form long chains and complex molecules. Silicon, on the other hand, can only form bonds with a few other types of atoms, and it is difficult to form long chains of silicon atoms. This makes carbon better suited for forming the complex molecules that are necessary for life.
Stability
Carbon-carbon bonds are stronger than silicon-silicon bonds. This means that carbon-based molecules are more stable than silicon-based molecules. This is important for life because biological molecules need to be stable enough to function properly.
Solubility in water:
Water is a good solvent for carbon-based molecules, but not for silicon-based molecules. This means that carbon-based molecules can dissolve in water, which allows them to be transported around the body and to interact with each other. Silicon-based molecules, on the other hand, do not dissolve well in water, which would make it difficult for them to function in a biological system.
In addition to these factors, it is also worth noting that carbon is much more abundant in the universe than silicon. This means that it is more likely that life would evolve based on carbon than on silicon.
While it is possible that silicon-based life could exist elsewhere in the universe, there is no evidence to suggest that it does. All known life on Earth is carbon-based.