Astronomy Picture of the Day 8-17-03

Explanation: What could you see approaching Saturn aboard an interplanetary cruise ship? Your view would likely resemble this subtly shaded image of the gorgeous ringed gas giant. Processed by the Hubble Heritage project, the picture intentionally avoids overemphasizing color contrasts and presents a natural looking Saturn with cloud bands, storms, nearly edge-on rings, and the small round shadow of the moon Enceladus near the center of the planet's disk. Of course, seats were not available on the only ship currently en route, the Cassini spacecraft. Cassini flew by Jupiter at the turn of the millennium and is scheduled to arrive at Saturn in the year 2004. After an extended cruise to a world 1,400 million kilometers from the Sun, Cassini will tour the Saturnian system, conducting a remote, robotic exploration with software and instruments designed by denizens of planet Earth.

Hubble Heritage site caption for the above image:

NASA's Hubble Space Telescope has provided images of Saturn in many colors, from black-and-white, to orange, to blue, green, and red. But in this picture, image processing specialists have worked to provide a crisp, extremely accurate view of Saturn, which highlights the planet's pastel colors. Bands of subtle color - yellows, browns, grays - distinguish differences in the clouds over Saturn, the second largest planet in the solar system.
Saturn's high-altitude clouds are made of colorless ammonia ice. Above these clouds is a layer of haze or smog, produced when ultraviolet light from the sun shines on methane gas. The smog contributes to the planet's subtle color variations. One of Saturn's moons, Enceladus, is seen casting a shadow on the giant planet as it passes just above the ring system.
The flattened disk swirling around Saturn is the planet's most recognizable feature, and this image displays it in sharp detail. This is the planet's ring system, consisting mostly of chunks of water ice. Although it appears as if the disk is composed of only a few rings, it actually consists of tens of thousands of thin "ringlets." This picture also shows the two classic divisions in the ring system. The narrow Encke Gap is nearest to the disk's outer edge; the Cassini division, is the wide gap near the center.
Scientists study Saturn and its ring system to gain insight into the birth of our solar system.
Image Credit: NASA and The Hubble Heritage Team (STScI/AURA) Acknowledgment: R. G. French (Wellesley College)

Remember this image from April?

Yup, it's the same spacecraft. Early on in the mission, it flew by Earth on its way to Jupiter, and the environuts went wild, because of the extremely small chance that the Earth's gravity would pull it back in. Watch the same people go bonkers when NASA starts its launch plans for the Jupiter Icy Moons Orbiter, which will have a small nuclear reactor on board, which won't be activated until it is a safe distance away from the Earth.

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