page_title: Cassini–Huygens
section_title: Hexagon changes color
hierarchical_section_title: Cassini–Huygens / Selected events and discoveries / Hexagon changes color
caption_attribution_description: English: These two natural color images from NASA's Cassini spacecraft show the changing appearance of Saturn's north polar region between 2012 and 2016. Scientists are investigating potential causes for the change in color of the region inside the north-polar hexagon on Saturn. The color change is thought to be an effect of Saturn's seasons. In particular, the change from a bluish color to a more golden hue may be due to the increased production of photochemical hazes in the atmosphere as the north pole approaches summer solstice in May 2017. Researchers think the hexagon, which is a six-sided jetstream, might act as a barrier that prevents haze particles produced outside it from entering. During the polar winter night between November 1995 and August 2009, Saturn's north polar atmosphere became clear of aerosols produced by photochemical reactions -- reactions involving sunlight and the atmosphere. Since the planet experienced equinox in August 2009, the polar atmosphere has been basking in continuous sunshine, and aerosols are being produced inside of the hexagon, around the north pole, making the polar atmosphere appear hazy today. Other effects, including changes in atmospheric circulation, could also be playing a role. Scientists think seasonally shifting patterns of solar heating probably influence the winds in the polar regions. Both images were taken by the Cassini wide-angle camera. The Cassini mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini. The Cassini imaging team homepage is at http://ciclops.org.
context_page_description: The Cassini–Huygens space-research mission, commonly called Cassini, involved a collaboration between NASA, the European Space Agency, and the Italian Space Agency to send a probe to study the planet Saturn and its system, including its rings and natural satellites. The Flagship-class robotic spacecraft comprised both NASA's Cassini probe and ESA's Huygens lander, which landed on Saturn's largest moon, Titan. Cassini was the fourth space probe to visit Saturn and the first to enter its orbit. The two craft took their names from the astronomers Giovanni Cassini and Christiaan Huygens.
  Launched aboard a Titan IVB/Centaur on October 15, 1997, Cassini was active in space for nearly 20 years, with 13 years spent orbiting Saturn and studying the planet and its system after entering orbit on July 1, 2004. The voyage to Saturn included flybys of Venus, Earth, the asteroid 2685 Masursky, and Jupiter. The mission ended on September 15, 2017, when Cassini's trajectory took it into Saturn's upper atmosphere and it burned up in order to prevent any risk of contaminating Saturn's moons, which might have offered habitable environments to stowaway terrestrial microbes on the spacecraft.
context_section_description: Between 2012 and 2016, the persistent hexagonal cloud pattern at Saturn's north pole changed from a mostly blue color to more of a golden color. One theory for this is a seasonal change: extended exposure to sunlight may be creating haze as the pole swivels toward the sun. It was previously noted that there was less blue color overall on Saturn between 2004 and 2008.
caption: 2012 and 2016:
  hexagon color changes
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