SCIENCE

NASA has released this week the best views yet of a bizarre hexagon-shaped cloud that blankets Saturn’s north polar region. (National Geographic Newswatch)

Use our resources to better understand Saturn’s storms and other wild weather in the solar system.

Discussion Ideas

• Read through our terrific activity “Extreme Weather in Our Solar System,” and apply its critical thinking to the Nat Geo blog post about Saturn’s hexagon. The blog post says that scientists have known about Saturn’s hexagon since the 1980s, and the new images were taken almost a year ago. Why are we only learning about Saturn’s stormy north pole now?
  • Two reasons—technology and distance.
    • Technology: Scientists learn about weather on planets such as Saturn through telescopes and space probes. The probe that identified the hexagon was Voyager 1, while the probe that is currently studying Saturn is Cassini. Probes are incredibly complex and expensive instruments to design, launch, monitor, and maintain. This can make exploration to the outer solar system a very long process. (But a rewarding one! Voyager, launched in 1980, is now reaching the very edge of our solar system—and still transmitting data! Exciting!)
    • Distance: Saturn is a long way from Earth—about 3474 million kilometers. It took Cassini-Huygens about seven years to reach Saturn, traveling at about 16.4 kilometers per second. (NASA’s Cassini spacecraft was part of a joint mission with the European Space Agency’s Huygens spacecraft—together, the largest interplanetary spacecraft ever built. Cassini continues to orbit and study Saturn, while Huygens became the first probe to land on Titan, a moon of Saturn.) Due to the amazing distance, it takes a long time for Cassini to transmit data to scientists, who must then analyze and interpret the data before sharing it with the public. And we’re so glad they do. Thank you, NASA!

• Scientists say Saturn’s hexagon is a jet stream. What is a jet stream? (Our encyclopedic entry on the subject might help provide some answers.)
  • A jet stream is a very fast-moving air current (wind) whipping around a planet at high altitudes.
  • Saturn’s hexagon is a jet stream that acts as a barrier, with atmospheric conditions inside distinct from those outside. “Inside the hexagon there are fewer large haze particles and a concentration of small haze particles, while outside the hexagon, the opposite is true. The jet stream that makes up the hexagon seems to act like a barrier, which results in something like the ‘ozone hole’ in the Antarctic,” according to NASA. The six-sided air current contains many vortices (similar to hurricanes we see on Earth). The largest vortex is what the Nat Geo news blog calls the “red rose” over the north pole. Other vortices appear as red or white ovals.

• Storms, even those with strong vortexes like hurricanes or typhoons, rarely last for more than a week on Earth. Why has the hexagon lasted for so long? Why has Jupiter’s famous Great Red Spot (another swirling storm) lasted even longer?
  • The Nat Geo news blog gives a great explanation. “Unlike Earth, where landforms disrupt weather patterns, Saturn is a gas giant. That means jet streams like the hexagon can whirl around the planet unimpeded for long periods of time.” There are no mountains, valleys, or bodies of water to alter the path of storms on gas giants.