Spirals are everywhere, from the tiniest fragile snail shells to the vast arcs of the cosmos. They can be beautiful, and violent too—just consider hurricanes (including Hurricane Dorian, of course), Jupiter’s Great Red Spot, and a big storm on Neptune.
The effect that governs these storms is called the Coriolis effect: When a storm is hovering over a planet or object that is in movement, it will spin because of the rotation of the planet. Spiral galaxies, though, take that form for very different reasons. Like solar systems that take shape from disks of gas around stars, galaxies are subject to similar physical phenomena but at much larger scales. We have the Voyager program to thank for some of this week’s spirals: When Voyager 1 first flew past Jupiter in 1979, it photographed the monster tempest swirling around and over on itself, and in 1989 Voyager 2 flew past Neptune and spied a small spiral storm that NASA nicknamed “Scooter.” Farther beyond are galaxies like our own spiral that contain gorgeous illuminated arms speckled with starlight.