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posted by martyb on Thursday December 12 2019, @04:23AM   Printer-friendly
from the wise-crack dept.

Explaining the Tiger Stripes of Enceladus

Saturn's tiny, frozen moon Enceladus is a strange place. Just 300 miles across, the moon is thought to have an outer shell of ice covering a global ocean 20 miles deep, encasing a rocky core. Slashed across Enceladus' south pole are four straight, parallel fissures or "tiger stripes" from which water erupts. These fissures aren't quite like anything else in the solar system.

"We want to know why the eruptions are located at the south pole as opposed to some other place on Enceladus, how these eruptions can be sustained over long periods of time and finally why these eruptions are emanating from regularly spaced cracks," said Max Rudolph, assistant professor of earth and planetary sciences at the University of California, Davis.

[...] Enceladus' surface temperature is about negative 200 degrees Celsius, so if a crack formed in the ice, you would expect it to freeze shut pretty quickly. Yet the south polar fissures remain open, and in fact reach all the way to the liquid ocean below. That's because liquid water within the fissure is sloshed around by tidal forces produced by Saturn's gravity, releasing energy as heat, Rudolph said. That stops the crack from freezing shut.

The release of pressure from the fissures stops new cracks from forming elsewhere on the moon, such as at the north pole. But at the same time, water vented from the crack falls back as ice, building up the edges of the fissure and weighing it down a bit. That causes the ice sheet to flex, the researchers calculate, just enough to set off a parallel crack about 20 miles away. "Our model explains the regular spacing of the cracks," Rudolph said.

Also at Carnegie Science.

Cascading parallel fractures on Enceladus (DOI: 10.1038/s41550-019-0958-x) (DX) (arXiv)


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  • (Score: 3, Informative) by aristarchus on Thursday December 12 2019, @07:39PM (1 child)

    by aristarchus (2645) on Thursday December 12 2019, @07:39PM (#931506) Journal

    More than aware, Busstard! Responsible for some of it. But also well aware that the average college age person is usually only able to find videos of cats and persons playing video games. Those who "profess" are more guides than gatekeepers, because knowledge is not the same as wisdom, and data is even more stupid. Perhaps we are more midwives of the mind, as Socrates suggests in the Theaetetus [wikisource.org].

    As for those beyond the age of learning, whose minds are slipping into the certainty of old age and the getting off of their lawns, the plethora of human knowledge is even more useless to them, for they have forgot more than anyone else will ever know, and they have started watching Faux News non-stop.

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  • (Score: 2) by The Mighty Buzzard on Thursday December 12 2019, @08:48PM

    by The Mighty Buzzard (18) Subscriber Badge <themightybuzzard@proton.me> on Thursday December 12 2019, @08:48PM (#931527) Homepage Journal

    Nobody without a disease preventing it is beyond learning. You've neglected an entire, rich world of complaining in your quest to avoid telling kids to get off your lawn. And you've missed out on learning why old men do it in the first place. I'd just tell you but it's one of those things you have to learn for yourself.

    --
    My rights don't end where your fear begins.