APOD: Fresh Tiger Stripes on Saturn's... (2020 Apr 27)

[APOD Robot]

Fresh Tiger Stripes on Saturn's Enceladus

Explanation: How will humanity first learn of extraterrestrial life? One possibility is to find it under the icy surface of Saturn's moon Enceladus. A reason to think that life may exist there are long features -- dubbed tiger stripes -- that are known to be spewing ice from the moon's icy interior into space. These surface cracks create clouds of fine ice particles over the moon's South Pole and create Saturn's mysterious E-ring. Evidence for this has come from the robot Cassini spacecraft that orbited Saturn from 2004 to 2017. Pictured here, a high resolution image of Enceladus is shown from a close flyby. The unusual surface tiger stripes are shown in false-color blue. Why Enceladus is active remains a mystery, as the neighboring moon Mimas, approximately the same size, appears quite dead. A recent analysis of ejected ice grains has yielded evidence that complex organic molecules exist inside Enceladus. These large carbon-rich molecules bolster -- but do not prove -- that oceans under Enceladus' surface could contain life. Another Solar System moon that might contain underground life is Europa.

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[rj rl]

What a remarkable little world.

[TerribleTadpole]

I love zooming in close to these ice worlds and cruising across the surface, exploring the craters and cracks and other formations. I try to imagine the blocks adrift before they freeze in place, or try to trace out the cracks as they cross each other to see which are older and which are younger.

I believe that it's almost inevitable that we will life here, and everywhere else where the chemicals and environment allow it to begin. The evidence from Earth is that life began almost as soon as conditions allowed it. So as long as the liquid beneath is not too hot, and not so turbulent that it would disrupt delicate phospholipid membranes, I'm confident that we will find self-sustaining chemistry happening.

[orin stepanek]

be nice to drag this little world into the goldilocks zone
and let the ice melt!

[Ann]

enceladusstripes_cassini_960.jpg

be nice to drag this little world into the goldilocks zone
and let the ice melt!

Oh no, Enceladus would act like a pool cue wreaking absolute havoc in the Solar system!!

Or am I too pessimistic? Perhaps a strong inward drift of tiny little Enceladus in the Solar system wouldn't affect the orbits of the planets too much?

(Tiny or not, I wouldn't want Enceladus to hit me, or the Earth, in the head!)

Ann

[orin stepanek]

enceladusstripes_cassini_960.jpg

be nice to drag this little world into the goldilocks zone
and let the ice melt!

Oh no, Enceladus would act like a pool cue wreaking absolute havoc in the Solar system!!

Or am I too pessimistic? Perhaps a strong inward drift of tiny little Enceladus in the Solar system wouldn't affect the orbits of the planets too much?

(Tiny or not, I wouldn't want Enceladus to hit me, or the Earth, in the head!)

Ann

No;No! We put it in a safe Orbit; then we have a little world with easy access!

[NCTom]

Is there any way to tell the difference in the ages of the surfaces where craters are still visible and the regions where a new surface has been created around the tiger stripes?

[sillyworm 2]

Just mentioned the goldilocks zone to my wife yesterday.Bringing this moon closer perhaps wouldn't do more damage than what we are already instigating.I say..go for it!

[Chris Peterson]

enceladusstripes_cassini_960.jpg

be nice to drag this little world into the goldilocks zone
and let the ice melt! :mrgreen:

Oh no, Enceladus would act like a pool cue wreaking absolute havoc in the Solar system!! 🙀

Or am I too pessimistic? Perhaps a strong inward drift of tiny little Enceladus in the Solar system wouldn't affect the orbits of the planets too much?

It's only 500 km across- about the same as asteroids like Pallas and Vesta. Even if it passed close enough to Earth to graze the atmosphere it wouldn't materially alter our orbit. If it became an inner system body it wouldn't disrupt any planetary orbits. A direct hit, of course, would be bad. Very bad.

[Chris Peterson]

be nice to drag this little world into the goldilocks zone
and let the ice melt! :mrgreen:

It's essentially already in a goldilocks zone, given conditions (tidal heating, perhaps) that allow for a liquid ocean and geothermal energy sources.

[TheZuke!]

be nice to drag this little world into the goldilocks zone
and let the ice melt!

My guess (hardly scientific); is that if Enceladus were brought close enough to the Sun to melt the ice, the gravity and atmosphere of such a small "moon" would not be enough to keep the water from vaporizing and leaving, resulting in a smaller dry rock.


Now, drag it into a Martian orbit, the same will occur, but some of the vapor could condense on Mars, giving human colonies a better chance of survival.

[Chris Peterson]

be nice to drag this little world into the goldilocks zone
and let the ice melt! :mrgreen:

My guess (hardly scientific); is that if Enceladus were brought close enough to the Sun to melt the ice, the gravity and atmosphere of such a small "moon" would not be enough to keep the water from vaporizing and leaving, resulting in a smaller dry rock.
:cry:

Now, drag it into a Martian orbit, the same will occur, but some of the vapor could condense on Mars, giving human colonies a better chance of survival.
:mrgreen:

Yes, it would essentially become a big comet. But it doesn't contain enough water to do much for Mars, even if the liquid water could somehow be moved there. As far as "condensation" though... nope. There's no mechanism by which vacuum thin water vapor in Martian orbit would make it to the surface.

[Ann]

Is there any way to tell the difference in the ages of the surfaces where craters are still visible and the regions where a new surface has been created around the tiger stripes?

This set of global, color mosaics of Saturn's moon Enceladus was produced from images taken by NASA's Cassini spacecraft during its first ten years exploring the Saturn system. These are the first global color maps of these moons produced from the Cassini data.

---

Plume particle deposition rates on Enceladus' surface in mm/year for the eight sources proposed in Spitale and Porco (2007) and for particle sizes 0.6 − 2 µm, 2 − 4 µm, 4 − 6 µm, and 6 − 15 µm. Source: https://www.researchgate.net/figure/Plume-particle-deposition-rates-on-Enceladus-surface-in-mm-year-for-the-eight-sources_fig2_322818976

---

Don't know if this helps any, but at least you can see what parts of Enceladus are heavily cratered and which are hardly cratered at all. Note in the set of pictures at right how ice particles from the tiger strips are spread over the surface of Enceladus.

Ann

[sp0ck]

Regarding Mimas, NASA says it's (continuing the Monty Python skits) "not dead yet!":

• The moon Mimas, whose Herschel Crater makes it look like the Death Star from "Star Wars," was thought to be an old, dead world, according to Cassini project scientist Linda Spilker. But Cassini scientists found evidence that it too may have a subsurface ocean, or at least a football-shaped water-ice core. “It’s curious. Mimas and Enceladus are the same size,” Spilker said, but Enceladus has water jets while Mimas appears not to. The reason for their differences is unknown.

link: https://solarsystem.nasa.gov/moons/satu ... y_zone_otp

I don't know if it's wise to drag moons from their location to a more habitable zone, either. They work like they do now because of where they are. So many variables change when shifting distance from Sol, gravity relationships, etc. Like an eager kid in a research lab, shoving things about, upsetting so much delicate balance. I would say we have a bit of discovery and understanding before we reach the ability to relocate moons safely.

[orin stepanek]

I only dream them up, don't explain them! Just an amusement on my part! If you're dreaming; may as well dream big! Tain't gonna happen anyway; at least, not in this man's lifetime!

[Chris Peterson]

:shock: I only dream them up, don't explain them! Just an amusement on my part! :mrgreen: If you're dreaming; may as well dream big! Tain't gonna happen anyway; at least, not in this man's lifetime!

If we had the technology to move huge asteroids around, who knows what else we could do?

[orin stepanek]

I only dream them up, don't explain them! Just an amusement on my part! If you're dreaming; may as well dream big! Tain't gonna happen anyway; at least, not in this man's lifetime!

If we had the technology to move huge asteroids around, who knows what else we could do?

Plus one Chris! That's very true; but 100 years ago we could do much less than what we can! do today!

[neufer]

Fresh Tiger Stripes on Saturn's Enchiladas

---

Explanation: How will humanity first learn of extraterrestrial life? One possibility is to find it under the chili surface of Saturn's moon Enchiladas. A reason to think that life may exist there are long features -- dubbed tiger stripes -- that are known to be spewing from the moon's chili interior into space. These surface cracks create clouds of fine particles over the moon's South Pole and create Saturn's mysterious E-ring. Evidence for this has come from the robot Cassini spacecraft that orbited Saturn from 2004 to 2017. Pictured here, a high resolution image of Enchiladas is shown from a close flyby. Why Enchiladas is active remains a mystery, as the neighboring moon Tacos, approximately the same size, appears quite dead. A recent analysis of ejected grains has yielded evidence that complex organic molecules exist inside Enchiladas. These large carbon-rich molecules bolster -- but do not prove -- that oceans under Enchiladas' surface could contain life.

[Interested Observer]

Is it possible that Mimas lost most of its water when it was struck by whatever made the giant crater? This might explain why it shows no signs of the same activity as Enceladus. Who knows, maybe some of the water on Enceladus came from Mimas. Although, I suspect most of it would have ended up in the rings on either side of Mimas.