Scientists may have figured out how cosmic dust particles grow and aggregate to form planets – and in turn this application may improve dust handling in industrial processes here on earth.
Previously, it was known that adhesion in outer space causes dust particles to stick together. Researchers also knew large particles combine due to gravitational pull, a key process in the creation of asteroids and planets.
However, the process between these two extremes – how aggregates grow – has largely remained a mystery until now.
The study, published in the journal Nature Physics, found particles under microgravity – similar to conditions believed to be in interplanetary space – develop strong electrical charges spontaneously and stick together, forming large aggregates.
Despite the common rule that like-charges repel, the researchers found like-charged aggregates came together due to the sheer strength of the charges, polarising one another to act like magnets.
According to the researchers, similar processes happen on earth where fluidised bed reactors produce a range of products, including plastics to pharmaceuticals.
During this process, blowing gas pushes fine particles upwards and when particles aggregate due to static electricity, they can stick to reactor vessel walls, leading to shutdowns and poor product quality.
“We may have overcome a fundamental obstacle in understanding how planets form,” said co-author Troy Shinbrot, a professor at Rutgers University-New Brunswick, New Jersey, USA.
“Mechanisms for generating aggregates in industrial processes have also been identified and that – we hope – may be controlled in future work. Both outcomes hinge on a new understanding that electrical polarisation is central to aggregation.”
The study, led by researchers at the University of Duisburg-Essen in Germany, may also lead to new ways to control fine particle aggregation in industrial processing.
It appears that introducing additives that conduct electricity may be more successful for industrial processes than traditional electrostatic control approaches, according to Shinbrot.
The researchers want to investigate the effects of material properties on sticking and aggregation, and potentially develop new approaches to generating and storing electricity.
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