Saturday, November 26, 2016

O/T Planetary Science: NASA's Cassini Begins... Its End.

We will almost undoubtedly learn much new astrophysical geological science, about the chemical composition (and various proportions -- of the icy rock-slab sizes -- from motes of dust, to perhaps car sizes) of Saturn's gorgeous rings -- in the next ten months. But we will also sacrifice the Cassini spacecraft to do so. She has enjoyed an immensely productive twelve year run, so we should not feel terribly blue. But as it is with all ends, I cannot help but feel a little sentimental -- just a little.

At right, courtesy of the CGI whizzes (in a now reduced animated GIF form) at the New York Times Science staff, we may see what the last several orbits (in gold) will look like -- compared to the earlier 12 years' worth (in blue). Dipping so close means. . . burning nearby, as opposed to freezing, at a distance. So it goes. Here is a bit from the Gray Lady:

. . . .Cassini has gradually shifted into an orbit that takes it over the planet’s north and south poles and then down into a series of increasingly vertiginous-looking dives perpendicular to the plane of its buttery glowing rings.

Starting on Wednesday, as shown here, with a gravitational nudge from the moon Titan, Cassini is set to commence a series of 20 dives just outside the outer edge of the main ring system. Along the way the spacecraft will try to sample ring particles and gases that live there in its vicinity, and pass only 56,000 miles above Saturn’s cloud tops. . . .

Eventually, in mid-September 2017, the spacecraft will make a final, forceful plunge -- disappearing into the clouds of Saturn and then -- almost immediately -- be completely incinerated by the generated friction. [Not long before that, we will have eye-witnessed a complete eclipse -- directly over the city north and east of Nashville, Tennessee.] So as I sip my Saturday morning coffee, fresh OJ, and watch the ends of a November sun slowly crest the taller buildings here, I am thinking some sentimental celestial thoughts. Thoughts of a long and fondly orbiting, if not near-by, shepherd moon -- copper in color, and ageless -- in her grace. Smile. . .


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