Wow, what a perspective! The Cassini Orbiter took this photo – a mosaic of 36 images made through three color filters – on Oct. 10 from a highly inclined orbit that lets us peer over both the north and south poles of the ringed planet. Since Earth and Saturn are both stuck in the same flat plane of the solar system, we can never see the planet from the top-over perspective Cassini can.
Three main rings are visible – A, the outermost, B, the widest and brightest and C, the innermost and barely visible hugging Saturn’s disk. Cassini normally orbits the planet in its equatorial plane, where most of Saturn’s rings and its moon are located, but mission control directed the probe into a highly-inclined orbit for studies of its polar regions and magnetic field. Also tipped our way is the mysterious polar hexagon, a 6-sided wave pattern in the clouds centered on Saturn’s north pole.
Cassini doesn’t carry the fuel to change its orbit on its own. Instead, NASA pumps up its orbital inclination by stealing gravitational energy from Saturn’s largest moon Titan. Several Titan flybys, one building atop another, are enough to send it reeling over the poles at an inclination of 62 degrees.
When Cassini arrived in 2004 it was northern winter and Saturn’s clouds had a bluish tint. Nine years later, it’s early summer in the northern hemisphere and the clouds are distinctly more butterscotch-hued. Investigations have found that Increasing ultraviolet light from the sun creates a yellowish haze. During the winter season, when sunlight is less intense, the haze clears, letting us see further down in the atmosphere where the molecules scatter blue light like they do on Earth, giving Saturn a more bluish tint. The blue is further enhanced by methane gas, which absorbs red light.
Two weeks earlier amateur astrophotographer Gordan Ugarkovic made his own Cassini montage of the ringed planet. It appeared on the Oct. 21 Astronomy Picture of the Day. Take a look – it’s a beauty.
Ready for one more succulent image? This one has nothing to do with planets. It’s Comet Encke in the morning sky taken by Michael Jaeger of Austria on Oct. 31. Encke is currently visible in binoculars in the constellation Virgo and trails a long, flagellum-like tail of glowing gases called an ion tail. As it approaches perihelion on Nov. 21 it’s becoming brighter and more active. We’ll have more on how our four morning comets are doing soon.