Saturn is probably the single most iconic image in all of astronomy--so iconic that it was, literally, the official Discover magazine icon for a number of years. Yet, amazingly, scientists continue to find new ways to look at the ringed planet, uncovering details never before seen by human eyes. If you follow space images, you probably saw the stunning polar view of Saturn, taken by NASA's Cassini spacecraft from a height of 935,000 miles. And that picture tells only a small part of the story.
Backlit Saturn shows rings, planet, and an intricate system of shadows in ways impossible to see from Earth. (Credit: NASA/Cassini/Gordan Ugarkovic) Two things that got largely overlooked in last week's gasping news coverage. First, the image was taken by Cassini and transmitted back to Earth while the federal government was officially shut down--a poetic reminder of what humans can achieve when they are working together effectively. Second, that even while NASA employees were on furlough, other space enthusiasts were still hard at work making good use of the data NASA was already collecting. Among those enthusiasts is Gordan Ugarkovic, a self-described "guy who does programming for a living...but in free time I like to fool around with image processing." Modesty be damned, what he really does is quite magical. He digs through Cassini images released to the Planetary Data System and creates his own color versions of images that NASA has released only in grayscale (what you and I would call "black & white"). The image I'm showing here is another one of his--a different view than the one that stunned the world last week. I highly recommend visiting Ugarkovic's Photostream for more fabulous space views. But wait--there's more. NASA has just released another landmark image of Saturn, also taken by Cassini. The impact of this one is not quite as immediate. In its own way, though, it offers just as much head-spinning beauty (click below for a better look). Here we get a double dose of novel perspective. We are seeing Saturn as it appears from behind, on the other side away from Earth, looking back at the sun. And we are looking at the planet and its rings not in light but in infrared rays.
Slice of Saturn--an infrared view of the rings and the heat of the planet.(Credit:NASA/JPL-Caltech/University of Arizona/Cornell) Adjust your perspective--imagine you are watching Saturn eclipse the sun, watching through a slit-shaped window in your spacecraft--and you begin to appreciate what you are seeing. The colors are not real; instead they represent the wavelength of the infrared rays, with blue representing the shortest ("hottest") and red denoting the longest ("coolest") emission. Because you are viewing Saturn from behind, all of the usual logic is turned on its head. The middle rings, which appear bright from Earth, are dark here, because they are thick with particles that block the sun's light. The outer rings, which normally appear faint, stand out bright here because they contain fine particles that scatter light like cigarette smoke. (NASA, being more health-conscious, likens the effect to the scatting of headlights off fog on a dark night.) The inner rings are somewhat bright as well, because they contain fairly transparent particles that let sunlight shine through. In the extended version of the image, you can even see the extremely fine ice particles blasted out of geysers on Saturn's moon Enceladus.
Older infrared image of Saturn, released in 2010, shows seasonal heat (red) at the planet's south pole. (Credit: NASA/JPL/ASI/University of Arizona) Then--whoa, Saturn itself is red! That's because you are looking at heat emitted by the planet. You can see cloud patterns and weather systems in silhouette, visible in the places where they block the heat escaping from Saturn's atmosphere. This image contains a staggering amount of information. It show the effects of seasons and weather systems on Saturn, it shows the structure of the rings, it shows the size of the particles in the rings, it even shows what the whole ring system is made of. Spectacular all around. And knowing how things work, more Saturn beauty is on the way. Follow me on Twitter: @coreyspowell
