Asymmetric vibrations in plasma disks may explain how planets form around stars and supermassive black holes
Researchers at the Princeton Plasma Physics Laboratory (PPPL) have discovered a new physical phenomenon that may explain how planets form from disks of material orbiting stars and supermassive black holes. In a unique laboratory experiment simulating cosmic conditions using rotating metal cylinders filled with a conductive metallic liquid, they found that an asymmetric wobble within a free-flowing layer causes particles to move inward—a process essential for planetary body formation.
Contrary to the well-known theory that these vibrations are mainly created by the interaction between plasma and magnetic fields in gravitational fields, the new study published inPhysical Review Letters Reveals that the shaking mechanism may be more common, and also occur as a result of velocity differences between adjacent plasma streams—a region known as the "free shear layer."
According to Dr. Yin Wang, a senior researcher at PPPL and lead author of the paper:
"Our finding suggests that these types of tremors may be much more common in the universe, and may underlie the formation of many more solar systems than we previously thought."
The experiment is based on a device called MRI Experiment, which simulates a stellar heating disk under laboratory conditions using two rotating cylinders and a liquid filling of galinstan—a mixture of gallium, indium, and tin. Magnetic fields were passed through the system and analyzed using advanced simulation software, including Dedalus and SFEMaNS.
The findings confirmed that these vibrations—called “nonaxisymmetric magnetorotational instability” (Nonaxisymmetric MRI)—cause slow particles to converge inward and form bodies like planets, while fast particles are ejected outward.
Prof. Fatima Ebrahimi, a research associate, explained:
"We have managed to solve a long-standing astrophysical puzzle — how non-uniform plasma motion can cause any cosmic disk to wobble and contract toward the center of gravity."
The research was conducted in collaboration with other scientists from PPPL and Princeton University, including Professor Jeremy Goodman, Professor Hantou Ji, and researcher Eric Gilson.
More of the topic in Hayadan:
