Parabolic Flight Experiments Delve into Planetary Formation

What happens in a protoplanetary disk to create planetesimals around a star? We know the general story -- the material begins to clump together and eventually grows from dust grains to rocky bodies capable of sticking together to make planets. But, how does that dust begin the aggregation journey? That's what a research team from the Switzerland wanted to know. So, they did experiments aboard parabolic micro-gravity flights to find an answer.