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.
Jupiter’s iconic Great Red Spot has been churning for hundreds of years. And while it is slowly getting smaller, it’s still so large that it can contain the entire Earth. Voyager 1 took this photo in 1979 when the spacecraft flew past, capturing the behemoth storm (and many others) in great detail.Photograph: NASA/JPL
Further out in our solar system, spiral storms spin and chug away on the surface of Neptune. The planet’s dark oval storm stands out, but just below that to the right is a storm dubbed “Scooter,” which Voyager 2 discovered in 1989. Just like on Earth, Jupiter, and other planets with atmospheres, the storms on Neptune come and go. We will need another trip back there to find out what new tempests have formed over the last 30 years.Photograph: NASA/JPL
The vertical galaxy on the left is called NGC 4302 and the other is NGC 4298. Captured by the Hubble Space Telescope, they are actually quite similar in terms of shape and composition; we’re just seeing them from two very different perspectives. One difference: The galaxy at left has absorbed more dust, making it appear more red than its pinwheel counterpart.Photograph: NASA Goddard