Algorithm

Composite number

Chemical physics

Mathematical physics

Materials science

Atomic physics

Germanium

Computer science

Silicon

Carbon fibers

Earth (classical element)

Physics

Nanotechnology

Organic chemistry

Oxygen

Astronomy

Composite material

Astrobiology

Chemistry

Optoelectronics

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

While life on Earth continues to be discovered in unlikely environments, the underlying biochemistry is all very similar, based on the element carbon, and requiring liquid water. We consider alternate biochemistries based on elements other than carbon, including other group IVA elements, such as silicon and germanium, and solvents other than water. Terminal electron acceptors other than oxygen are also discussed. A fundamental issue is raised related to the detection of, and even the definition of life, whether it is carbon or non-carbon based. An extreme example of this issue would be in consideration of speculative life based on electrically charged dusty plasmas, which may have no physical body.

Potential alternate life biochemistries