Saturn's hexagon

A partial view of Saturn's north pole, 2016

Saturn's hexagon is a persistent approximately hexagonal cloud pattern around the north pole of the planet Saturn, located at about 78°N.[1][2][3] The sides of the hexagon are about 14,500 km (9,000 mi) long,[4][5][6][7] which is about 2,000 km (1,200 mi) longer than the diameter of Earth.[8] The hexagon may be a bit more than 29,000 km (18,000 mi) wide,[9] may be 300 km (190 mi) high, and may be a jet stream made of atmospheric gases moving at 320 km/h (200 mph).[4][5][10] It rotates with a period of 10h 39m 24s, the same period as Saturn's radio emissions from its interior.[11] The hexagon does not shift in longitude like other clouds in the visible atmosphere.[12]

Saturn's hexagon was discovered during the Voyager mission in 1981, and was later revisited by Cassini-Huygens in 2006. During the Cassini mission, the hexagon changed from a mostly blue color to more of a golden color. Saturn's south pole does not have a hexagon, as verified by Hubble observations. It does, however, have a vortex, and there is also a vortex inside the northern hexagon.[13] Multiple hypotheses for the hexagonal cloud pattern have been developed.

  1. ^ Godfrey, D.A. (1988). "A hexagonal feature around Saturn's north pole". Icarus. 76 (2): 335–356. Bibcode:1988Icar...76..335G. doi:10.1016/0019-1035(88)90075-9.
  2. ^ Sanchez-Lavega, A.; Lecacheux, J.; Colas, F.; Laques, P. (1993). "Ground-Based Observations of Saturn's North Polar Spot and Hexagon". Science. 260 (5106): 329–32. Bibcode:1993Sci...260..329S. doi:10.1126/science.260.5106.329. PMID 17838249. S2CID 45574015.
  3. ^ Overbye, Dennis (August 6, 2014). "Storm Chasing on Saturn". New York Times. Retrieved August 6, 2014.
  4. ^ a b Sánchez-Lavega, A.; et al. (7 March 2014). "The long-term steady motion of Saturn's hexagon and the stability of its enclosed jet stream under seasonal changes". Geophysical Research Letters. 41 (5): 1425–1431. arXiv:2402.06371. Bibcode:2014GeoRL..41.1425S. doi:10.1002/2013GL059078. S2CID 130345071.
  5. ^ a b Fletcher, L.N.; et al. (3 September 2018). "A hexagon in Saturn's northern stratosphere surrounding the emerging summertime polar vortex". Nature Communications. 9 (3564): 3564. arXiv:1809.00572. Bibcode:2018NatCo...9.3564F. doi:10.1038/s41467-018-06017-3. PMC 6120878. PMID 30177694.
  6. ^ Imster, Eleanor (12 August 2014). "The Eye of Saturn". Earth & Sky. Retrieved 13 September 2018.
  7. ^ Williams, Matt (10 May 2017). "Saturn's Hexagon Will be the Star of the Cassini Finale". Universe Today. Retrieved 13 September 2018.
  8. ^ "New images show Saturn's weird hexagon cloud". NBC News. December 12, 2009. Retrieved December 5, 2013.
  9. ^ NOTE: A planar hexagon width (diameter) is twice the side (radius); but since the planet Saturn approximates an oblate spheroid, the radius of such an hexagon may be a bit greater than its side length (ie, 14,500 km), making the width (diameter) a bit greater than 29,000 km.
  10. ^ Wall, Mike (4 September 2018). "Bizarre Hexagon on Saturn May Be 180 Miles Tall". Space.com. Retrieved 4 September 2018.
  11. ^ Godfrey, D. A. (1990). "The Rotation Period of Saturn's Polar Hexagon". Science. 247 (4947): 1206–8. Bibcode:1990Sci...247.1206G. doi:10.1126/science.247.4947.1206. PMID 17809277. S2CID 19965347.
  12. ^ Baines, Kevin H.; Momary, Thomas W.; Fletcher, Leigh N.; Showman, Adam P.; Roos-Serote, Maarten; Brown, Robert H.; Buratti, Bonnie J.; Clark, Roger N.; Nicholson, Philip D. (2009). "Saturn's north polar cyclone and hexagon at depth revealed by Cassini/VIMS". Planetary and Space Science. 57 (14–15): 1671–1681. Bibcode:2009P&SS...57.1671B. doi:10.1016/j.pss.2009.06.026.
  13. ^ Sánchez-Lavega, A.; Pérez-Hoyos, S.; French, R. G. (2002). "Hubble Space Telescope Observations of the Atmospheric Dynamics in Saturn's South Pole from 1997 to 2002". American Astronomical Society. 34: 13.07. Bibcode:2002DPS....34.1307S. Archived from the original on September 5, 2008.