The spin axis of Saturn's moon Enceladus may have reoriented due to a collision with another body:
Saturn's icy, ocean-bearing moon Enceladus may have tipped over in the distant past, according to recent research from NASA's Cassini mission. Researchers with the mission found evidence that the moon's spin axis -- the line through the north and south poles -- has reoriented, possibly due to a collision with a smaller body, such as an asteroid.
Examining the moon's features, the team showed that Enceladus appears to have tipped away from its original axis by about 55 degrees -- more than halfway toward rolling completely onto its side. "We found a chain of low areas, or basins, that trace a belt across the moon's surface that we believe are the fossil remnants of an earlier, previous equator and poles," said Radwan Tajeddine, a Cassini imaging team associate at Cornell University, Ithaca, New York, and lead author of the paper.
[...] Whether it was caused by an impact or some other process, Tajeddine and colleagues think the disruption and creation of the tiger-stripe terrain caused some of Enceladus' mass to be redistributed, making the moon's rotation unsteady and wobbly. The rotation would have eventually stabilized, likely taking more than a million years. By the time the rotation settled down, the north-south axis would have reoriented to pass through different points on the surface -- a mechanism researchers call "true polar wander."
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A study has found that a "porous"/sandy/muddy core can increase the energy released by gravitational tidal friction inside Saturn's moon Enceladus. This could explain why the interior of the icy moon has not cooled down after billions of years:
A paper published in Nature Astronomy today presents the first concept that explains the key characteristics of 500 km-diameter Enceladus as observed by the international Cassini spacecraft over the course of its mission, which concluded in September.
This includes a global salty ocean below an ice shell with an average thickness of 20–25 km, thinning to just 1–5 km over the south polar region. There, jets of water vapour and icy grains are launched through fissures in the ice. The composition of the ejected material measured by Cassini included salts and silica dust, suggesting they form through hot water – at least 90ºC – interacting with rock in the porous core.
These observations require a huge source of heat, about 100 times more than is expected to be generated by the natural decay of radioactive elements in rocks in its core, as well as a means of focusing activity at the south pole.
The tidal effect from Saturn is thought to be at the origin of the eruptions deforming the icy shell by push-pull motions as the moon follows an elliptical path around the giant planet. But the energy produced by tidal friction in the ice, by itself, would be too weak to counterbalance the heat loss seen from the ocean – the globe would freeze within 30 million years.
[...] In the new simulations the core is made of unconsolidated, easily deformable, porous rock that water can easily permeate. As such, cool liquid water from the ocean can seep into the core and gradually heat up through tidal friction between sliding rock fragments, as it gets deeper.
Powering prolonged hydrothermal activity inside Enceladus (DOI: 10.1038/s41550-017-0289-8) (DX)
Previously: Hydrogen Emitted by Enceladus, More Evidence of Plumes at Europa
Cassini Finds Evidence of Change in Enceladus's Spin Axis
Could a Dedicated Mission to Enceladus Detect Microbial Life There?
How the Cassini Mission Led a 'Paradigm Shift' in Search for Alien Life
(Score: -1, Spam) by Anonymous Coward on Thursday June 01 2017, @04:27PM
Gangs of Niggerfish swim the oceans of Enceladus.
(Score: 2) by bob_super on Thursday June 01 2017, @04:58PM (2 children)
There are just so many ways to read this summary as Enceladus trying to get a White House job...
(Score: 2) by DannyB on Thursday June 01 2017, @06:48PM (1 child)
There are more ways to creatively read it than you think. Think Different. (with no intent to offend anyone, using a fictional POV . . .)
Sounds kind of sissy to me.
OMG, this isn't talking about one of THOSE . . .
That sounds pretty fishy to me.
(gasp!) get the children out of the room!
Never fear, Smith is here.
(Score: 2) by bob_super on Thursday June 01 2017, @06:52PM
Also works with a fat drunk getting a tattoo.
(Score: 2) by DannyB on Thursday June 01 2017, @06:56PM
How much more than a million years?
Long enough for the possibility of life to have formed since the event?
Is it more likely whether or not Enceladus ever had any micro biological life, that it no longer does after such an event?
Never fear, Smith is here.