For the first time in history, physicists have directly observed how highly charged dust-sized particles form the beginnings of planets.
The scientists were able to watch these particles attracting and capturing others to build up clusters, the University of Chicago reported. This process can lead to the formation of "granular molecules," which resemble simple molecules.
The researchers used a free-falling stream of particles to create a low-gravity environment, and recorded it with a high-speed video camera. This allowed them to observe how charged grains in their mutual electrostatic interactions can undergo both attractive and repulsive trajectories that look similar to planetary orbits. This call attention the importance of the polarization effects in promoting the capture of grains through multiple collisions.
"This can have implications for the very earliest stages of planet formation, which is believed to start via collisions among interstellar dust grains," saidHeinrich Jaeger, the William J. Friedman and Alicia Townsend Professor in Physics. "Single head-on collisions typically do not dissipate enough energy to lead to sticking."
In the past, scientists have theorized that electrostatic interactions are what allows these types of particles to stick together, eventually forming planets. Now, researchers have finally observed cluster growth by successive capture made possible by long-range electrostatic interactions. A related report also provided calculations that could help explain some configurations of granular molecules.
"One thing their paper makes clear is that the effects we were able to track directly with the granular material have wide-ranging importance for much smaller particles, including colloids, nanoparticles and molecules," Jaeger said.
The findings were published in a recent edition of the journal Nature.
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