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“The Beginning of the End of Our Historic Exploration of Saturn”
published during a waxing gibbous moon.
12/09/2016

Cassini is now on its farewell tour of Saturn, but it’s getting some great pictures on this final leg of its journey.

Historic Exploration

This image shows a part of Saturn’s massive hexagonal jet stream that encircles that planet’s North Pole. The circle to the top right is a long-raging storm at the center of the hexagon. Credit: NASA/JPL-Caltech/Space Science Institute

The NASA spacecraft, Cassini has orbited Saturn since 2004, sending back data and images of auroras and lightning, dusty rings, and icy moons. It’s been a wild ride, and it’s still going strong. The latest images sent back from the probe give researchers a close up of one of Saturn’s more distinctive features (other than the rings, of course) a huge hexagonal jet stream that encircles a circular storm raging at Saturn’s North Pole.

Historic Exploration

Put a hex on it-Cassini captured these images of the Hexagonal jet stream in Saturn’s northern reaches. The four different images each show how the area looks in different wavelengths of light from clockwise from the top left; the wavelengths are violet, red, near infrared and infrared light. Credit: NASA/JPL-Caltech/Space Science Institute

Jet streams, which are essentially rivers of wind in a planet’s atmosphere, are also present on Earth and Jupiter, but they don’t have the same hexagonal shape. On Earth, the position of the jet stream can vary. This hexagonal shape on Saturn has persisted for at least 30 years. It was first spotted in the 1980s.

Scientists are still trying to model how Saturn’s weird jet stream developed into its strange shape, but one idea is that the polar atmospheric streams are shaped by adjacent currents. The hexagon is about 20,000 miles across and extends 60 miles deep into the atmosphere. Researchers hope that they can get more pictures of the area before Cassini’s mission ends next year.

“This is it, the beginning of the end of our historic exploration of Saturn. Let these images — and those to come — remind you that we’ve lived a bold and daring adventure around the solar system’s most magnificent planet,” said Carolyn Porco, Cassini imaging team lead at Space Science Institute, Boulder, Colorado.

Historic Exploration

Ring Grazing Orbits–Cassini is currently going through its ring grazing orbits, shown here in gray on the left. Next April, it will move closer to the planet (blue orbits) before eventually crashing into Saturn (orange). Credit: NASA/JPL-Caltech

The images of the hexagonal storm were captured as part of Cassini’s ring grazing orbits, which the spacecraft will be engaged in between November 2016 and April 2017. After April, Cassini will begin diving into a gap between Saturn and its rings before eventually moving into position for its grand finale–a crash into Saturn itself which is scheduled for September 15, 2017.  Until then, Cassini will keep sending back beautiful shots like the ones seen here.