AMATEUR NATURALIST

Saturn and its disconcerting rings

Posted July 01, 2012, at 7:12 p.m.
Saturn's rings cast shadows near the planet's equator as it approaches its equinox in August 2009.
NASA/JPL/Space Science Institute
Saturn's rings cast shadows near the planet's equator as it approaches its equinox in August 2009.

The Cassini spacecraft has been orbiting around Saturn for about eight years, now, sending back strange pictures pretty much the whole time.

There are weird pictures of the planet’s rings, pictures of Saturn backlit by the sun. Bizarre images of some kind of jets streaming from its moon Enceladus. Pictures have come back of Saturn’s largest moon, Titan, showing methane lakes and undiscovered Titanic countries where, it is proposed, life might once have spawned, died out, or could come back.

Saturn was strange all along. Its rings badly confused Galileo, mainly because of the limited capabilities of his telescopes, but also because in 1610 he did not know what he was seeing. In the later 1600s, the French astronomer Giovanni Cassini observed that the rings are not one solid plane, but divided. In 2004 the Cassini spacecraft found the rings are not flat, but wavy or corrugated.

The fact that we can see the rings at all is startling, since they’re less than a mile thick. The three other “gas giant” planets — Jupiter, Uranus and Neptune — have rings, too, but they’re so wispy it took spacecraft to notice them.

In a small telescope the image of Saturn is tiny. It has a flat-white to faintly goldish sheen, lustrous like Jupiter and Mars. But unlike them it does not appear as a disk which your eye can comfortably turn into a sphere or globe. What baffled Galileo were the strange protrusions, which he at first thought were separate planets locked in place. But the protrusions were actually those rings. They can be disconcerting if you let them.

They’re made of rock, dust and ice left over from some kind of barrage that occurred after Saturn formed about 4.5 billion years ago. Comets or asteroids (no one knows for sure what) annihilated its newly made moons and broke everything to pieces as if there had been a cosmic war. The debris settled into orbit around the giant planet, and huge, flat rings formed from fine rock and ice. After some uncertain eon, it is believed, a second bombardment began. The present moons show the scars. Three small moons, Telesto, Calypso and Tethys, somehow ended up in the same orbit. Mimas has a crater almost a third of its whole diameter. The potato-shaped moon Hyperion angles around bent over 45 degrees on its axis, implying it was struck and half-killed by something enormous. The moons shepherd the tiny ring particles. Saturn is surrounded by rubble.

In a small telescope the rubble becomes strangely beautiful. Striking and chilling. Poe, the master of weirdness, wrote that “the tone of [beauty’s] highest manifestation … is sadness,” which is a strange thing to say but maybe you can grasp it when you see Saturn shining up there with its rings.

It swings slowly around the sun once every 28 years or so, brooding. In ancient times it was the remotest known planet. The Greeks called it Cronos, the father of the gods, whose name is likely linked to the word for time, chronos, in the sense of huge, inexorable motion toward an end and chaos, which in the myths is sad — Cronos toppled his father Uranus, and then was overturned by his own son Zeus. The Romans called him Saturn, and in December celebrated saturnalia, a festival of reckless abandon as winter closed in. Our week ends on Saturn’s day.

Maybe this is not despair, but in here somewhere is an image of life’s inescapable decline. It is unlike any other phase of life, strange and disconcerting, and weirdly beautiful.

Dana Wilde’s collection of Amateur Naturalist and other writings, “ The Other End of the Driveway,” is available electronically and in paperback from Booklocker.com. A second collection, “ Nebulae: A Backyard Cosmography,” will be available soon.

 

 

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