5 Saturn Quirks That Cassini Unveiled
published during a waning gibbous moon.
09/20/2016

Cassini Unveiled

Credit: NASA/JPL

It’s the final countdown! A year from now, Cassini will collide into Saturn in a blaze of scientific glory in what NASA is calling the Grand Finale. Before it’s sent to its last resting place next fall, here are some of the unbelievable visuals and highlights of the spacecraft’s epic decades-long quest since its launch in 1997.

Cassini Unveiled

Credit: NASA/ESA

1. Sparkling auroras. 

Magnetotail sounds like an animal superhero that can destroy things with its rear, but it’s a feature that planets with a magnetic field have, such as Jupiter, Earth, and Uranus. Saturn has a magnetic tail, too, and when the sun emits a slew of solar wind, or charged particles that smash into Saturn, that long magnetotail wilts and reforms, which can be seen through its ultraviolet auroral displays. The shimmering green curtains we see on Earth aren’t that different from Saturn’s, and together with the Hubble Space Telescope, Cassini captured a 360-degree view of Saturn’s polar auroras.

2. Flickering space lightning.

Scientists first heard Saturnian lightning via radio emissions, but Cassini gave the sound life when it imaged flares of light for the first time ever. Cassini and Voyager both harnessed the radio waves, but it’s hard to actually witness any bolts because Saturn is so radiant that we can see it with the naked eye back on Earth. Even Saturn’s dark side doesn’t get too dim because the planet’s rings reflect more light than a full moon does on Earth, according to a NASA release. But Cassini snagged lightning on the day side during an annual massive, hurricane-like storm, each flash lasting less than a second. Using the pictures, scientists put together a movie showing lightning on another planet.

Cassini Unveiled

Credit: NASA/JPL-Caltech/Space Science Institute

3. A global superstorm. 

If you think Earth’s hurricanes are hefty, Saturn recently hosted a storm that encircled the whole planet. They’re referred to as Great White Spots, and the violent storm that formed in 2010 grew its pale tail for half a year. Saturn’s year is about 30 Earth years, and the megastorms actually take that long to form, typically making them annual occurrences. But this one in particular took form a decade early, giving Cassini the opportunity to examine the spot and learn that they spew water vapor that freezes, which paints the storms that ghostly color. Oh, and the storms can be as big as Earth’s diameter.

Cassini Unveiled

Credit: NASA/JPL-Caltech/SSI

4. Saturn’s stately crown.

Atop Saturn is a hexagonal jet stream with winds that whip around 200 miles per hour (322 km per hour). Voyager first spotted the powerful vortex in the 1980s, but Cassini was the first to peer at it more closely and unveil its symmetry. Earth has features like mountains that break up jet streams, as you may have experienced if you’ve ever flown on a plane and been tossed around in a bout of turbulence. But on Saturn, there aren’t any obstacles to break up the flow, so the long-lasting, phenomenon rages on, puzzling astronomers as they attempt to pinpoint what exactly is propelling it.

Cassini Unveiled

Credit: NASA/JPL/Space Science Institute

5. The planet’s never-before-seen rings.

We already know Saturn’s rings are majestic works of art, but Cassini found even more rings that are so faint, they’d never been seen before. The panoramic above was made using 165 images as Cassini floated in Saturn’s shadow and adjusted to simulate its natural color.