As swarms of small fragments interacted while orbiting Jupiter, the circumplanetary disk developed propagating density waves. According to Batygin, this is akin to how the arms of galaxies form, meaning young Jupiter likely had a spiral pattern around it. However, Batygin tells Astronomy that even if Earth had existed at that time (it formed about 90 million years after Jupiter’s moons), the spirals would have been obscured by millions of miles of gas between us. This beautiful high-resolution simulation shows such a disk around the young exoplanet PDS 70 c.