NASA’s Cassini spacecraft has provided scientists the first close-up, visible-light views of a behemoth hurricane swirling around Saturn’s north pole.
In high-resolution pictures and video, scientists see the hurricane’s eye is about 1,250 miles (2,000 kilometers) wide, 20 times larger than the average hurricane eye on Earth. Thin, bright clouds at the outer edge of the hurricane are traveling 330 mph(150 meters per second). The hurricane swirls inside a large, mysterious, six-sided weather pattern known as the hexagon.
“We did a double take when we saw this vortex because it looks so much like a hurricane on Earth,” said Andrew Ingersoll, a Cassini imaging team member at the California Institute of Technology in Pasadena. “But there it is at Saturn, on a much larger scale, and it is somehow getting by on the small amounts of water vapor in Saturn’s hydrogen atmosphere.”
Scientists will be studying the hurricane to gain insight into hurricanes on Earth, which feed off warm ocean water. Although there is no body of water close to these clouds high in Saturn’s atmosphere, learning how these Saturnian storms use water vapor could tell scientists more about how terrestrial hurricanes are generated and sustained.
Both a terrestrial hurricane and Saturn’s north polar vortex have a central eye with no clouds or very low clouds. Other similar features include high clouds forming an eye wall, other high clouds spiraling around the eye, and a counter-clockwise spin in the northern hemisphere.
A major difference between the hurricanes is that the one on Saturn is much bigger than its counterparts on Earth and spins surprisingly fast. At Saturn, the wind in the eye wall blows more than four times faster than hurricane-force winds on Earth. Unlike terrestrial hurricanes, which tend to move, the Saturnian hurricane is locked onto the planet’s north pole. On Earth, hurricanes tend to drift northward because of the forces acting on the fast swirls of wind as the planet rotates. The one on Saturn does not drift and is already as far north as it can be.
“The polar hurricane has nowhere else to go, and that’s likely why it’s stuck at the pole,” said Kunio Sayanagi, a Cassini imaging team associate at Hampton University in Hampton, Va.
Scientists believe the massive storm has been churning for years. When Cassini arrived in the Saturn system in 2004, Saturn’s north pole was dark because the planet was in the middle of its north polar winter. During that time, the Cassini spacecraft’s composite infrared spectrometer and visual and infrared mapping spectrometer detected a great vortex, but a visible-light view had to wait for the passing of the equinox in August 2009. Only then did sunlight begin flooding Saturn’s northern hemisphere. The view required a change in the angle of Cassini’s orbits around Saturn so the spacecraft could see the poles.
“Such a stunning and mesmerizing view of the hurricane-like storm at the north pole is only possible because Cassini is on a sportier course, with orbits tilted to loop the spacecraft above and below Saturn’s equatorial plane,” said Scott Edgington, Cassini deputy project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “You cannot see the polar regions very well from an equatorial orbit. Observing the planet from different vantage points reveals more about the cloud layers that cover the entirety of the planet.”
Cassini changes its orbital inclination for such an observing campaign only once every few years. Because the spacecraft uses flybys of Saturn’s moon Titan to change the angle of its orbit, the inclined trajectories require attentive oversight from navigators. The path requires careful planning years in advance and sticking very precisely to the planned itinerary to ensure enough propellant is available for the spacecraft to reach future planned orbits and encounters.
Image credit: NASA/JPL-Caltech/SSI
Theories of Everything by Dayna Thacker
Thacker on her work:
John Muir wrote, “When we try to pick out anything by itself we find that it is bound fast by a thousand invisible cords that cannot be broken, to everything in the universe.”
This body of work takes inspiration from the “thousand invisible cords” of modern string theory, ancient Islamic sacred geometry, and the principles of ecology. These complex areas of study have several overlapping concerns: the harmony of relationships; the correlation between the very large and infinitely small; symmetry; repetition; beauty; an appreciation for the elegance of a perfectly balanced system; and the extreme interconnection of everything.
Imaging Bacteria: Jon Sasaki’s New Photographic Work
Jon Sasaki’s recent photo-based work situates itself decisively at the nexus of humour, history, art and science. Three works in particular, Microbes Swabbed From a Palette Used By A.J. Casson, Microbes Swabbed From a Palette Used By Frederick Varley, and Microbes Swabbed From a Palette Used By Tom Thomson, all from 2013, embody Sasaki’s characteristic critical wit; the delicate abstract formations are bacterial cultures, grown in Petri dishes and born of microbes culled from paint palettes. Enshrined at the McMichael Canadian Art Collection, the palettes belong to late members of the Group of Seven.
A nod to the history and mythology of Canadian art and a persistent fascination with landscape, the microcosmic bacterial formations, while formally abstract, hint to painterly landscapes in their subtle tones, organic structures and tectonic shapes. The process of swabbing Group of Seven palettes speaks to a different mythology: that of the ‘Great Canadian painter.’ Is the use of such specific microbes, tied inextricably to the individual painter, an homage to the artist – or a clever critique of artistic genius? Regardless of critical intent, the inherent visual variety of the work affords each image a personality and the ability to act as a portrait of the artist whose palette microbes were used.
Sasaki’s photographs bridge the methodical and the mythological, re-imagining both the traditional Canadian landscape painting and the artist-worship trope. His employment of science-based methods in artistic practice works to undermine harsh disciplinary categories. Classification is cast off playfully; at the site of this betrayal, a rare experience of simultaneous wonder and amusement is afforded.
These and other new works by Jon Sasaki are on view at Jessica Bradley Gallery in Toronto from January 12 through March 16, 2013.
More of Sasaki’s work can be seen here.