IPB

Welcome Guest ( Log In | Register )

10 Pages V  « < 7 8 9 10 >  
Reply to this topicStart new topic
Pluto System Speculation
Bill Harris
post Jan 15 2016, 03:17 PM
Post #121


Senior Member
****

Group: Members
Posts: 2997
Joined: 30-October 04
Member No.: 105



I've been examining satellite imagery of the Arctic/Antarctic and Greenland. This is probably the closest Terrestrial analogy to Sputnik Planum we have. And going further afield from strict analogy, I've also looked at the ice-sheets/lava fields of Iceland for ideas away from the Tombaugh region.


--------------------
Go to the top of the page
 
+Quote Post
HSchirmer
post Jan 16 2016, 02:29 PM
Post #122


Member
***

Group: Members
Posts: 684
Joined: 24-July 15
Member No.: 7619



QUOTE (Bill Harris @ Jan 14 2016, 05:07 PM) *
That has occurred to me, too. A clathrate couldn't dissolve and still be a clathrate. But could it weather (physically break down) into a minimum clathrate "cell" or structure? I tend to think of clathrates as being akin to silicates at these temperatures, but that is not a strict analogy since the SiO4 and H2O bonds are way different. What would clathrate nanoparticles behave like?


There is some work on ice clathrates of methane CH4 and ethane C2H8 forming at geologic depths on Titan.
http://spaceref.com/saturn/icy-aquifers-on...e-rainfall.html

The inference from Titan is that in the icy bodies of the outer solar system, clathrates could form a thick subterranean layer.



At these temperatures, really over-simplifying

water ice = basaltic ocean crust
volatile ices = oceans
clathrates = continental crust

The study about Titan and clathrates notes that clathrates are good at separating liquids with different sized molecules.
For Pluto at depth, where you might have liquid methane, liquid N2 and liquid CO, that separation effect could be very interesting.
Methane clathrates would be similar on Titan and Pluto, and although carbon monoxide and nitrogen are chemically different from ethane,
the molecules are roughly the same size as ethane, so the cage-size based fractionation should be very similar.

So, Plutonian crustal clathrates might show the fractionation effect mentioned for Titan, e.g. they might be able to separate liquid phases
because of the smaller size of the CH4 molecules compared to the larger CO and N2 molecules.
One result of this could be that some areas on Pluto are underlain by deep methane aquifers while other areas are underlain by aquifers of carbon monoxide and nitrogen.

On Titan, the clathrates not only separate chemicals but appear to polymerize then, methane to ethane, ethane to propane.
So, perhaps at depth, Pluto clathrates could catalyze methane, ethane, propane; and also carbon monoxide to polycarbonyl.

Finally, if clathrates can catalyze polymerization of three CH4 molecules into propane,
then perhaps starting with CH4, N2, and CO results in polymerization into red tholins?
Go to the top of the page
 
+Quote Post
HSchirmer
post Jan 16 2016, 03:12 PM
Post #123


Member
***

Group: Members
Posts: 684
Joined: 24-July 15
Member No.: 7619



QUOTE (Gladstoner @ Dec 27 2015, 09:50 PM) *
Would that also be the case under various other conditions? As it turns out, water ice apparently can dissolve in liquid nitrogen, but can be done only on a small scale under difficult conditions in the laboratory. Imagine how complex the interactions are in the vast scale and intricacies of Pluto's crust and mantle, not to mention all the unknowns (and unknowables). It may be centuries before we have a solid grasp of what makes Pluto tick.


There's a bit of discussion about clathrates, CH4, N2 etc, in regards to Enceladus.

http://www.unmannedspaceflight.com/index.p...ost&p=77810
A Clathrate Reservoir Hypothesis for Enceladus' South Polar Plume
Susan W. Kieffer, Xinli Lu, Craig M. Bethke, John R. Spencer, Stephen Marshak, and Alexandra Navrotsky
Science 314, 1764-1766 (2006)
Abstract
Supporting Online Material

See also the accompanying News of the Week article "A Dry View of Enceladus Puts a Damper on Chances for Life There" by Richard Kerr.

Go to the top of the page
 
+Quote Post
Bill Harris
post Jan 16 2016, 11:36 PM
Post #124


Senior Member
****

Group: Members
Posts: 2997
Joined: 30-October 04
Member No.: 105



So clathrates can be considered to be the zeolites of an icy world. Strangerer and strangerer...

--Bill


--------------------
Go to the top of the page
 
+Quote Post
HSchirmer
post Jan 17 2016, 12:15 AM
Post #125


Member
***

Group: Members
Posts: 684
Joined: 24-July 15
Member No.: 7619



QUOTE (Bill Harris @ Jan 16 2016, 11:36 PM) *
So clathrates can be considered to be the zeolites of an icy world. Strangerer and strangerer...

--Bill


Well, not quite. It's not about large void spaces like zeolites,
rather it's the incorporation of a "volatile" into the solid crystal structure of the "rock".

On early earth, the first rocks to cool would be basalt.
Basalt is the dense black rock that makes the ocean crust.
When you re-melt basalt in the presence with water, (e.g. run basalt through a subduction zone)
the water is incorporated into the mix and you get granite, the less-dense light colored rock that
makes the continental crust.

So, on outer planets, "pure" H2O ices would be analogous to "basalt",
while the H2O clathrates would be analogous to granites as rock that has incorporated a volatile into
the crystal structure.



Go to the top of the page
 
+Quote Post
Bill Harris
post Jan 18 2016, 03:10 PM
Post #126


Senior Member
****

Group: Members
Posts: 2997
Joined: 30-October 04
Member No.: 105



That is an excellent analogy. I tend to look at terrestrial clathrates, with the methane clathrate or methane hydrate being a type example, as a magical, mystical substance that binds up methane and therefore is akin to a zeolite. The classical description is a "cage structure enclosing methane molecules" and so on. Fairly simplistic.

I need to go do some reading...

--Bill


--------------------
Go to the top of the page
 
+Quote Post
Bill Harris
post Feb 4 2016, 11:03 PM
Post #127


Senior Member
****

Group: Members
Posts: 2997
Joined: 30-October 04
Member No.: 105



QUOTE (atomoid @ Feb 4 2016, 04:51 PM) *
astounding.. i hadnt noticed the three curious conical features before (see excerpt below), the opposite shadowing from surrounding terrain suggests they are depressions.
[attachment=38876:sinx.png]


Early Lunar studies suggested that "conical" craters are the product of either volcanic (or gas) vents or of the sapping (or draining) of fine dust into a subsurface cavity. Given that these craters occur on a water-rocky terrain on could speculate that they are gas vents.

--Bill


--------------------
Go to the top of the page
 
+Quote Post
Webscientist
post Feb 10 2016, 09:30 PM
Post #128


Junior Member
**

Group: Members
Posts: 98
Joined: 30-November 05
From: Antibes, France
Member No.: 594



Excellent and captivating presentation (at Drexel University) by Alan Stern that I've just followed on youtube:

https://www.youtube.com/watch?v=mIfqjbCNO3s

Regarding the famous "snakeskin" terrain, he says the composition involves methane ice. The pseudo-stalagmites may be composed of methane ice...

He says there are sinuous channels which may be related to ancien flows of liquid nitrogen at a time when the atmosphere was heavier, denser.

He postulates the presumed convection process associated with the polygons of Sputnik Planum may be related to an internal heat source from the progressive freezing of a water ocean beneath the icy crust. The heat is expelled upward from the freezing process... That's at least his favorite assumption at the moment.

Go to the top of the page
 
+Quote Post
HSchirmer
post Feb 12 2016, 03:50 AM
Post #129


Member
***

Group: Members
Posts: 684
Joined: 24-July 15
Member No.: 7619



QUOTE
...
if Pluto does have the occasional runaway green house, (or impact)
it might get to 63 Kelvin with a transient one-tenth bar atmosphere and have liquid N2 for a while.

And it seems like the volume of ice in sputnik is just about what you would see if that entire transient
atmosphere froze out into one polar deposit.



Bump.

Wow. Flowing liquid nitrogen may have carved drainage channels Pluto?


https://www.youtube.com/watch?v=mIfqjbCNO3s
One hour, two minutes in.

Noticed that a stitched black & white lorri image by wildespace shows the area with the channels
http://www.unmannedspaceflight.com/index.p...st&p=227627
Attached thumbnail(s)
Attached Image
Attached Image
 
Go to the top of the page
 
+Quote Post
Bill Harris
post Feb 13 2016, 03:26 PM
Post #130


Senior Member
****

Group: Members
Posts: 2997
Joined: 30-October 04
Member No.: 105



What wonderful worlds. Even though the temperature is low they ar not stuck in a deep-freeze.

--Bill


--------------------
Go to the top of the page
 
+Quote Post
HSchirmer
post Mar 22 2016, 02:02 PM
Post #131


Member
***

Group: Members
Posts: 684
Joined: 24-July 15
Member No.: 7619



QUOTE (HSchirmer @ Dec 24 2015, 08:32 PM) *
Interesting idea. You need about .1 bar of atmosphere to allow N2 to flow like a liquid on pluto.
Basically, if Pluto had a transient warming event, either procession or perhaps a collision,
the surface temperature would rise to 63 Kelvin, then you'd start melting N2 into atmosphere,
and once you have .1 bar of N2, you could get liquid.
...
Rather interesting actually - if Pluto does have the occasional runaway green house, (or impact)
it might get to 63 Kelvin with a transient one-tenth bar atmosphere and have liquid N2 for a while.


Bump- So Pluto is like the "Diamond Mountains of Lower Pomerania" That's the Brothers Grimm fairy tale, where a finch sharpening it's beak wears down a mountain. Instead, every 800,000 years, Pluto warms, a thin atmosphere forms which allows brooks and rivers of N2 flow for a few years. Then back to endless winter to wait almost a million years...

http://phenomena.nationalgeographic.com/20...-lake-on-pluto/
QUOTE
“The pressure changes radically,” says New Horizons principal investigator Alan Stern. Today, he says, Pluto’s atmospheric pressure is “atypically low,” noting that at maximum it can be more than 20,000 times the current reading.

That means surface temperatures must be fluctuating enough to mess with the nitrogen on Pluto’s surface, driving it from a frozen solid into a gas. And sometimes, the temperature and pressure occasionally rise high enough for liquid nitrogen to flow on the surface.

The last time temperatures were sufficiently high to melt nitrogen was around 800,000 years ago, when Pluto’s orbital alignment led to its most extreme warm climate, says MIT’s Richard Binzel.
Go to the top of the page
 
+Quote Post
Explorer1
post Mar 22 2016, 05:57 PM
Post #132


Senior Member
****

Group: Members
Posts: 2073
Joined: 13-February 10
From: Ontario
Member No.: 5221



I recall that there have been findings that Mars has had extreme periods of tilt in its past, because of the lack of large satellites to prevent a wobble, but how would Pluto's axis undergo precession in such an extreme way, though? Doesn't Charon stabilize the axis just like our Moon does for Earth? Certainly intriguing...
Go to the top of the page
 
+Quote Post
JRehling
post Mar 22 2016, 07:42 PM
Post #133


Senior Member
****

Group: Members
Posts: 2530
Joined: 20-April 05
Member No.: 321



What would be relevant are the moment of inertia of the system and the torque that is applied to the system. We can't know the internal moments of inertia of Pluto and Charon, but I would guess that the system's MOI can be estimated from externally observable quantities. There should be an answer for this, but it's a research project to get to the bottom of it.

Pluto's orbit is tightly controlled by Neptune, which says something about how much Neptune influences the Pluto-Charon system. But the answer to your question involves pages of math.
Go to the top of the page
 
+Quote Post
HSchirmer
post Mar 22 2016, 09:32 PM
Post #134


Member
***

Group: Members
Posts: 684
Joined: 24-July 15
Member No.: 7619



QUOTE (Explorer1 @ Mar 22 2016, 05:57 PM) *
I recall that there have been findings that Mars has had extreme periods of tilt in its past,
because of the lack of large satellites to prevent a wobble,


Eh, as to Mars, there was a recent paper and discussion that the weight
of the Tharsis bulge actually shifted the martian equator by 20 degrees.
Basically, Martian valleys/tropical rain bands and ice fields only make sense
if you turn Mars by 20 degrees, then the highlands and lowlands are balanced.

Pluto should be susceptible to the same crust-shifting effect, ice re-deposition
causes a huge mass redistribution, which forces the outer crust to shift.
Neat thing is, on Pluto, every 800,000 years, that ice could melt or sublimate,
and then re-deposit somewhere else, causing ANOTHER round of crust shifting.

Interesting to think of that interationc between atmosphere and planet.
On Venus, it's possible that the atmosphere has actually reversed the rotation of the planet,
on Pluto, it's possible that the weight of the frozen atmosphere reorients the poles every few million years.
Go to the top of the page
 
+Quote Post
Explorer1
post Mar 22 2016, 11:03 PM
Post #135


Senior Member
****

Group: Members
Posts: 2073
Joined: 13-February 10
From: Ontario
Member No.: 5221



QUOTE (JRehling @ Mar 22 2016, 11:42 AM) *
But the answer to your question involves pages of math.


No surprise there wink.gif

Thanks for the info from you both, though still odd to consider. A Plutonian equivalent of the Milankovitch cycles? The Sun is too distant to have an effect, so it must be either Neptune or internal forces. Long term observations will shed light (no pun intended)...
Go to the top of the page
 
+Quote Post

10 Pages V  « < 7 8 9 10 >
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 29th March 2024 - 07:48 AM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member.