Intriguing evidence of life-like corkscrew structures that form from inorganic substances in space hint at the possibility that life beyond earth may not necessarily use carbon-based molecules as its building blocks. They may also point to a possible new explanation for the origin of life on earth.
V.N. Tsytovich of the General Physics Institute, Russian Academy of Science, in Moscow, working with colleagues there and at the Max-Planck Institute for Extraterrestrial Physics and the University of Sydney, Australia, studied the behavior of complex mixtures of inorganic materials in a plasma, essentially the fourth state of matter beyond solid, liquid and gas, in which electrons are torn from atoms leaving behind a miasma of charged particles.
Physicists have long assumed that there could be little organization in such a cloud of particles. However, Tsytovich and his colleagues demonstrated, using a computer model of molecular dynamics, that particles in a plasma can undergo self-organization as electronic charges become separated and the plasma becomes polarized, resulting in microscopic strands of solid particles that twist into corkscrew shapes, or helical structures. These helical strands are themselves electronically charged and are attracted to each other.
Not only do these helical strands interact in a counterintuitive way in which like can attract like, but they also undergo changes that are normally associated with biological molecules, such as DNA and proteins, said the researchers. They can divide, or bifurcate, to form two copies of the original structure that can also interact to induce changes in their neighbors and even evolve into yet more structures as less stable ones break down, leaving behind only the fittest structures in the plasma.
"These complex, self-organized plasma structures exhibit all the necessary properties to qualify them as candidates for inorganic living matter," says Tsytovich, "they are autonomous, they reproduce and they evolve".
He added that the plasma conditions needed to form these helical structures are common in outer space. However, plasmas can also form under Earth conditions such as the point of a lightning strike. The researchers suggest that perhaps an inorganic form of life emerged on the primordial earth, which then acted as the template for the more familiar organic molecules we know today.
The Daily Galaxy via iop.org