Amateur Naturalist

The craters of winter

Posted March 13, 2011, at 6:53 p.m.
Saturn's cratered moon Hyperion is thought to be filled with caves.
Saturn's cratered moon Hyperion is thought to be filled with caves.

By the beginning of March, there was so much snow we felt like we were living in a crater. To get into the driveway, you passed between two gigantic pyramids like the ancient Lion Gate. It descends immediately and bends along a causewaylike track that in winter is lined by snowbanks. This year the banks have been so high the driveway became a sort of tunnel sloping to where it crosses the sticks-bowered brook, which has not been seen since December, then bottoming out among pine, maple, oak, hemlock and other trees sifting snow out of their branches and closing out the low-angled winter sunlight — leaving the ice there two to three miles thick, or so we estimated. The tunnel then re-ascends for about 30 feet and comes out in the yard, which on March 1 was encircled by 8-foot mountains of plowed-up snow. Welcome to Crater Troy.

If you looked at those steep walls too long you started to feel uneasy. They were covered with rocky-looking frozen debris and peaked with boulders you imagine must be the same on the slopes of K2. The walls were all moon-ice white. Buried somewhere under there was the ancient Mercedes, which we only drive in summer. We were closed off from the world.

One morning I was standing in the middle of this driveway nowhere looking up at the ice walls, and started thinking I’d seen this before. Rubble-strewn snowbanks or maybe glaciers, surrounding me. I wasn’t sure if it was from a childhood memory, or a dream, or another lifetime. Trying to remember was like clambering along an underground passage, then suddenly I was up the other side: The driveway crater was like Saturn’s weird moon Hyperion.

It is a potato-shaped thing around 250 miles long and 160 miles at its widest point (though these measurements are approximate). A spacecraft photo shows a huge crater gashing almost one whole side of it. The crater slopes are bright, steep and seem rubble-strewn. There are scores of other craters in the crater, with jagged-looking edges.

How Hyperion got that way is essentially unknown. It could be the last big chunk of a larger moon that got blown apart in a collision or in a bombardment Saturn’s environs are thought to have undergone eons ago. But Hyperion (named at the time of its discovery in 1848 after one of the Titans, about whom not a lot is revealed in ancient Greek texts) has other shadowy inexplicabilities, too. For one thing, instead of rotating smoothly and evenly like other moons and planets, it tumbles chaotically end over end and side over side. It orbits Saturn every 21 days near the much larger moon Titan, which makes three rounds for every four of Hyperion’s. Every time Hyperion passes into Titan’s gravity, it jostles, changes its spin axis and flails.

It turns out the jagged edges of Hyperion’s craters are made of water ice, just like Crater Troy. Hyperion’s density is so low its interior is thought to be a webwork of ice caverns. If somehow you could make your way through its constantly skewing 13-day spin and set foot on it, not only would you be standing at the bottom of winter looking up at ice walls, but you might also descend through openings in the craters to minus-300-degree caves. You might crawl down shadowy tunnels and find frozen debris and flitting landslide motions you wouldn’t think possible.

If you stayed down there long enough in that titanic darkness you might eventually wonder if it was an actual place or just a state of wintermind tumbling end over end around Saturn for the rest of eternity, or at least until the next bombardment of snow and ice. Winter after a long time freezes you with this feeling of craterous remoteness and claustrophobia you want to crawl out of, and can’t.

Anyway, along came a rainstorm the first weekend in March. The crater walls receded a little bit (thankfully for my sanity, you might say — I know I did), and the Lion Gate shrank. The increasing daylight turns the driveway from a tunnel into a mud slough. But it’s a sign of a return to the surface.

naturalist@dwildepress.net

SEE COMMENTS →

ADVERTISEMENT | Grow your business
ADVERTISEMENT | Grow your business

Similar Articles

More in Living