Planet drop

This video shows silicon dioxide – also called silica – dust particles being shot into a vacuum chamber in weightlessness to observe their growth, how they interact and stick together. The video was recorded during a drop tower experiment at the Zarm tower in Germany and played back at five times reduced speed.

Astronomers conclude that planets are formed out of cosmic dust and gas from an interstellar cloud around a new-born star, but exactly how dust particles start to assemble into larger celestial bodies is still a mystery.

Go back far enough in time and Earth will not have existed, but its formation must have started somewhere, sometime. And this very first clumping together of dust particles in zero gravity will be investigated in the ICAPS experiment.

Drop tower experiments allow for up to nine seconds of microgravity but the ICAPS team behind this experiment are aiming for more with a sounding rocket session that will allow researchers to watch up to six minutes of planet formation in progress.

The experiment aims to simulate growth of micrometre-sized particles – similar in size to talcum powder – to millimetre-sized aggregates and investigate the physical phenomenon of Brownian motion. This process is believed to be the main mechanism of how “planet embryos” evolved in the young Solar System.

The dramatic movement seen in the particles occurred when the "cloud manipulation system" that is part of ICAPS was switched on. This device keeps the dust cloud in place and also "squeezes" it. By toggling the cloud manipulation system on and off for roughly half of the time in weightless the researchers can compare how the dust aggregates form and better understand the difference when Brownian motion applies.

These experiments will provide insight into how dust first starts to clump together, and so into the very early stages of planet formation.