After orbiting Saturn for nine years, the Cassini space probe has made another incredible discovery about the ringed giant. NASA has recently released the above photo of an enormous hurricane centered on the planet’s north pole. The images are astoundingly beautiful and will hopefully help shed light on the composition and structure of Saturn and the other gaseous planets.
Here’s how NASA explains it:
https://www.youtube.com/watch?v=qHx3AQAn0T0
To be fair, the actual images are not this glamorous. They were taken in red and infrared wavelengths and the color that you see here was added to increase detail and contrast, but they are nonetheless spectacular to behold. To help you understand the color scheme, NASA explains:
The images were taken with Cassini’s wide-angle camera using a combination of spectral filters sensitive to wavelengths of near-infrared light…At Saturn, this scheme means colors correlate to different altitudes in the planet’s polar atmosphere: red indicates deep, while green shows clouds that are higher in altitude. High clouds are typically associated with locations of intense upwelling in a storm. These images help scientists learn the distribution and frequencies of such storms. The rings are bright blue in this color scheme because there is no methane gas between the ring particles and the camera.
Red indicates depth, and I love how a close-up on the eye of the storm makes Sauron’s look withered and impotent. The top of Saturn looks like lava swirling down a reinforced drain into hell.
The diameter of the storm on Saturn is estimated to be about 1,250 miles, twenty times bigger than the average terrestrial hurricane. The edges of the cyclone are spinning at 330 miles per hour. In comparison, the Hurricane Katrina was about 400 miles wide with sustained wind speeds of about 125 miles per hour.
The images also expose a rather odd quirk in Saturn’s atmosphere that scientists first discovered from images taken by the Voyager spacecraft about 25 years ago: There is an unusual jet stream that surrounds the north pole in the shape of a hexagon. This jet stream is incredibly large, about the width of two Earths side-by-side. Scientists previously had not been able to discover what was in the center because it had been winter on Saturn and the planet was tipped away from the sun. Without sunlight is was impossible to see the planet’s north pole.
However, with the long winter over (a year on Saturn is about 30 Earth years) the sun has finally risen over the pole. This allowed scientists to take these incredible images and document the giant hurricane that is centered and locked within the hexagonal jet stream.
Weirdly enough, there is also a tremendous hurricane on the other side of the planet as well that was discovered in 2006. Just like its brother in the north, it is fixed in position directly over the its pole. Larger than its northern counterpoint, the southern hurricane is a whopping 5,000 miles across, although it doesn’t enjoy its own polygonal ring surrounding it.
I’ve written about the Voyager spacecraft and my love of stellar exploration before. When Galileo viewed Saturn through his telescope in 1610 he became the first person to see its rings. However, because of the limitations of his lens he thought they were two moons encircling the gaseous planet. It’d be fun to play the time travel game and show him what we now know today, if the logistics involved wouldn’t kill him out of shock. (They most assuredly would.)
Science is such illuminating fun and the pace of discovery has quickened along with the means of acquiring knowledge. I follow a maxim that states that it’s always better to know than to not know, and tomorrow we’ll know just a little bit more.
Sources:
http://science.nasa.gov/science-news/science-at-nasa/2013/29apr_saturnhurricane/
http://www.scientificamerican.com/article.cfm?id=sandy-vs-katrina-and-irene
http://adsabs.harvard.edu/abs/1988Icar…76..335G
http://www.bbc.co.uk/news/science-environment-22351048
http://news.bbc.co.uk/1/hi/sci/tech/6135450.stm
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