Helices swirl in space-dust simulations
Aug 15, 2007
Swirling clouds of dust in space could harbour something akin to life -- according to computer simulations done by physicists in Russia, Germany and Australia. The simulations suggest that under certain conditions, dust particles could join together to form double-helix structures similar to DNA and even divide to create two identical copies of the same structure. Although the simulated dust is inorganic and so does not contain the carbon-based molecules found in all life on Earth, the researchers believe that their results hint at the possibility that inorganic life could exist elsewhere in the universe (New Journal of Physics 9 263).
Vadim Tsytovich and colleagues at the Russian Academy of Science along with researchers at the Max Planck Institute for Extraterrestrial Physics and the University of Sydney simulated the behaviour of mixtures of inorganic interstellar dust in a plasma, which is an extremely hot gas of charged particles. Such plasmas are common in space and can even occur naturally on Earth at the point of a lightning strike.
Dust particles in a plasma are themselves charged, which leads to electrostatic interactions between the particles. The researchers assumed that -- at certain separations -- two dust particles would be attracted to one another, while at other separations the particles would repel. A computer program was then used to simulate how a large number of dust particles would interact within a plasma.
The simulations suggested that under conditions commonly found in space, the dust particles first form a cylindrical structure that sometimes evolved into helical structures. Along some spirals, the radius of the helix was seen to change abruptly from one value to another and then back again, providing a mechanism for storing information in terms of the length and radius of a section of a spiral.
In some simulations, a spiral would divide into two, effectively reproducing itself. In other simulations, two spirals induced structural changes in each other, and some spirals even appeared to evolve with time into more robust structures.
While many scientists would balk at calling such structures life – if they indeed exist in the first place -- Tsytovich has no doubt. “These complex, self-organized plasma structures exhibit all the necessary properties to qualify as candidates for inorganic living matter,” he said. “They are autonomous, they reproduce and they evolve”. The team has also suggested that such inorganic life could have been a precursor to organic life here on Earth.
While these specific simulations have not been verified in the laboratory, experiments by other researchers on other dust-plasma systems have revealed the emergence of simple helical structures.
As for finding inorganic life in dust clouds surrounding nearby stars, the researchers say this could be done by looking for changes in infrared light from distant astronomical objects as it passes though a cloud of spirals – a measurement that could in principle be done with NASA’s Spitzer space telescope.
About the author
Hamish Johnston is editor of physicsworld.com