Organics and carbonates on Enceladus.

[RGClark]

Oct 5th, 2010
Warm ‘Perrier’ Ocean Could be Powering Enceladus’ Geysers.
"Finding the sodium in the icy grains in the plume is huge piece of evidence pointing to a subsurface ocean. Previously, Earth-based observations did not detect salts in the plume, and so scientists didn’t think a liquid ocean was possible. But infrared observations with an instrument on Cassini found the particles in the plumes include water ice, and substantial amounts of sodium and potassium salts and carbonates, as well as organics."
http://www.universetoday.com/75034/w...ladus-geysers/

The Cassini scientists suggested that some chemical reactions subsurface might be heating the ocean causing the geysers, but don't say what those chemical reactions are.
I still like the possibility it's due to radiogenic heating, though I don't have an explanation for why it should persist when the radioactivity should have died away long ago. I discussed this theory in this post to this forum a few years ago:

A possible origin for the jets of Enceladus.
15-January-2006 12:02 AM #1
RGClark
http://www.bautforum.com/showthread....adus.?p=654378

Note at the bottom I provide a cite of a prediction that radiogenic heating could cause sufficient gas release to crack asteroidal/cometary bodies, as has been seen with Enceladus.


Bob Clark

[marsbug]

You've got to hand it to Enceladus, ten years ago no-one would have seriously considered a moon 500km across having any activity, never mind a subsurface lake. One out of left field. Pity it will take so long to send another mission to the saturn system.

[A.DIM]

Oct 5th, 2010
Warm ‘Perrier’ Ocean Could be Powering Enceladus’ Geysers.
"Finding the sodium in the icy grains in the plume is huge piece of evidence pointing to a subsurface ocean. Previously, Earth-based observations did not detect salts in the plume, and so scientists didn’t think a liquid ocean was possible. But infrared observations with an instrument on Cassini found the particles in the plumes include water ice, and substantial amounts of sodium and potassium salts and carbonates, as well as organics."
http://www.universetoday.com/75034/w...ladus-geysers/

The Cassini scientists suggested that some chemical reactions subsurface might be heating the ocean causing the geysers, but don't say what those chemical reactions are.
I still like the possibility it's due to radiogenic heating, though I don't have an explanation for why it should persist when the radioactivity should have died away long ago. I discussed this theory in this post to this forum a few years ago:

A possible origin for the jets of Enceladus.
15-January-2006 12:02 AM #1
RGClark
http://www.bautforum.com/showthread....adus.?p=654378

Note at the bottom I provide a cite of a prediction that radiogenic heating could cause sufficient gas release to crack asteroidal/cometary bodies, as has been seen with Enceladus.


Bob Clark

Neat stuff, Bob, thanks!
It goes hand in hand with today's news: (Titan's) Atmosphere May Hold Ingredients for Life.

[A.DIM]

You've got to hand it to Enceladus, ten years ago no-one would have seriously considered a moon 500km across having any activity, never mind a subsurface lake. One out of left field. Pity it will take so long to send another mission to the saturn system.

Indeed.
Did you see this: Water discovered on second asteroid, may be even more common?
It's only 290km...

[Jim]

Thread hijack post - and replies - removed.

[whimsyfree]

Indeed.
Did you see this: Water discovered on second asteroid, may be even more common?
It's only 290km...

Ice out beyond the snow line is no surprise. 65 Cybele has an aphelion of 3au. It's odd they say "ice on asteroids may be more common than expected" but don't say how common it was expected to be before the observation of ice on 65 Cybele or how common it is expected to be now.

[A.DIM]

Ice out beyond the snow line is no surprise. 65 Cybele has an aphelion of 3au. It's odd they say "ice on asteroids may be more common than expected" but don't say how common it was expected to be before the observation of ice on 65 Cybele or how common it is expected to be now.

From what I've read it was assumed asteroids were mostly rocky material and too close to the sun to retain water ice. This discovery supports the idea it was asteroids as much as, if not more than, comets which delivered water and organics to Earth. This is off topic though. I was trying to reinforce what marsbug said about scientific assumptions and thinking being so different from only 10yrs ago and how that affects the missions in space.

[John Jaksich]

Oct 5th, 2010
Warm ‘Perrier’ Ocean Could be Powering Enceladus’ Geysers.
"Finding the sodium in the icy grains in the plume is huge piece of evidence pointing to a subsurface ocean. Previously, Earth-based observations did not detect salts in the plume, and so scientists didn’t think a liquid ocean was possible. But infrared observations with an instrument on Cassini found the particles in the plumes include water ice, and substantial amounts of sodium and potassium salts and carbonates, as well as organics."
http://www.universetoday.com/75034/w...ladus-geysers/

The Cassini scientists suggested that some chemical reactions subsurface might be heating the ocean causing the geysers, but don't say what those chemical reactions are.
I still like the possibility it's due to radiogenic heating, though I don't have an explanation for why it should persist when the radioactivity should have died away long ago. I discussed this theory in this post to this forum a few years ago:

A possible origin for the jets of Enceladus.
15-January-2006 12:02 AM #1
RGClark
http://www.bautforum.com/showthread....adus.?p=654378

Note at the bottom I provide a cite of a prediction that radiogenic heating could cause sufficient gas release to crack asteroidal/cometary bodies, as has been seen with Enceladus.


Bob Clark

That sounds plasusible to me--but could there be tidal forces from Saturn driving the internal heating, also? Chemical reactions alone would eventually equilibrate and not evolve any heat---there is most likely a source to drive the reactions in the interior --or subsurface for that matter--

[RGClark]

Neat stuff, Bob, thanks!
It goes hand in hand with today's news: (Titan's) Atmosphere May Hold Ingredients for Life.

Looks like our Solar System is awash with the ingredients for life. The only question is is it actually awash with life itself. Looks like it's time for a poll!

Bob Clark

[marsbug]

Ice out beyond the snow line is no surprise. 65 Cybele has an aphelion of 3au. It's odd they say "ice on asteroids may be more common than expected" but don't say how common it was expected to be before the observation of ice on 65 Cybele or how common it is expected to be now.

I've seen the early solar system frost line put as far out as 5 au, so this tightens things a bit. Bith these asteroids are big enough to be partially differentated, which could mean subsuface fluids and pre-biotic chemistry at some point in their histories. So there is some astro(pre)biological interest to the discovery to.

[whimsyfree]

I've seen the early solar system frost line put as far out as 5 au, so this tightens things a bit.

Really? I still put it at about 2.8au and this doesn't cause me to change my mind a bit. I predict traces of water will be found on many asteroids. I think the odds of finding life on an asteroid are astronomical.

[Glom]

It's not enough to have organics. You need to have self replicating organics. How do you get organics to self replicate? There is only one way: the Qi!

[marsbug]

Really? I still put it at about 2.8au and this doesn't cause me to change my mind a bit. I predict traces of water will be found on many asteroids. I think the odds of finding life on an asteroid are astronomical.

Well the Dawn mission team have put it as 'in the neighbourhood of' 3.5 au in their literature (Here, pages 5 and 6), as they are sending a mission to the asteroid belt I expect them to be well informed on the matter. Wikipedia gives a value of 2.7 au very close to yours.
2.8 au seems to match well with these discoveries but there seems to be enough disagreement that some researchers will have been surprised by them. Give yourself a slice of cake for knowing better (if you want)!

I assume you bring up the idea of asteroid life because I used the term:

astro(pre)biological

There I've bolded it so you can see what I did, although I tried to make it clear with the phrase:

pre-biotic chemistry

that I was talking about chemical precursors to life being present on asteroids.

[Bad Ronald]

Enceladus may be host to a subsurface sea of life then?

[RGClark]

That sounds plasusible to me--but could there be tidal forces from Saturn driving the internal heating, also? Chemical reactions alone would eventually equilibrate and not evolve any heat---there is most likely a source to drive the reactions in the interior --or subsurface for that matter--

The consensus was when the geysers were discovered that tidal forces from Saturn were insufficient to explain them.

Bob Clark

[whimsyfree]

Well the Dawn mission team have put it as 'in the neighbourhood of' 3.5 au in their literature (Here, pages 5 and 6), as they are sending a mission to the asteroid belt I expect them to be well informed on the matter. Wikipedia gives a value of 2.7 au very close to yours.
2.8 au seems to match well with these discoveries but there seems to be enough disagreement that some researchers will have been surprised by them. Give yourself a slice of cake for knowing better (if you want)!

It was something I picked up from somewhere, and after the fact posts count for nothing.

I assume you bring up the idea of asteroid life because I used the term: There I've bolded it so you can see what I did, although I tried to make it clear with the phrase: that I was talking about chemical precursors to life being present on asteroids.

I apologise if my post carried the inference that you had said otherwise. However, how meaningful is "pre-biotic chemistry"? If there was no biology subsequently, how was the chemistry "pre-biotic"? What counts as "chemical precursors to life"? amino acids? nucleobases? methane? water?

[HenrikOlsen]

The consensus was when the geysers were discovered that tidal forces from Saturn were insufficient to explain them.

But that was before the mass estimate was upped considerably by the Cassini fly-bys and tidal heating is quite dependent on the mass of what's being heated.

And it's tidal forces from Dione, not Saturn that is thought to be the main source of heat these days, seeing that it's face-locked to Saturn like our moon.

[marsbug]

It was something I picked up from somewhere, and after the fact posts count for nothing.
I apologise if my post carried the inference that you had said otherwise. However, how meaningful is "pre-biotic chemistry"? If there was no biology subsequently, how was the chemistry "pre-biotic"? What counts as "chemical precursors to life"? amino acids? nucleobases? methane? water?

I'll make this the last post I send on the subject, as I don't want to inadvertantly hijack this thread.

Technically no, its not pre-botic if it never leads to life. However, as far as my laymans understanding goes:
One goal of astrobiology is to help uncover how life began. On Earth, the best theories to date tell us, it began in an environment where organic carbon compounds and liquid water interacted in a rocky environment. Studying that chemistry in its natural state would be very helpfull in unravelling the origin of life. But most of the rocks from that time are destroyed or re-worked, and all the carbon chemistry is absorbed by life forms. Water and carbon bearing asteroids that underwent heating had the same kind of chemistry, but the chemistry was stopped after only a short time when the asteroid cooled. As no life ever arose there, and there have been no geological processes for billions of years it should be preserved as well as anything can be, waiting there for us to examine it.

Detailed analysis of carbon bearing meteorites, that show signs of being in contact with water on their parent bodies, have revealed a lot of chemicals that are used by life, such as nucleotides and amino acids. We can't say for sure that these are precursors to life as we haven't seen them come together to form a living organism yet, but its a reasonable guess that they are. So a detailed analysis of the parent body, or another asteroid like it, could be still more informative, and much more certain as we can get pristine samples.

On top of that, objects like these probably have added their carbon own chemistry to the surface of early Earth, so knowing whats in them helps us constrain the start conditions for the chemical road to life better.

Lastly:
'Chemical precursors to life' is a fairly open phrase I'll admit, the chemistry leading up to life probably involved all the things you list and a lot more. The attraction of heated carbon and water bearing asteroids is that samples of them could give us a chance to see how they reacted together, over many centuries, much like we think they did on early earth.

[Vultur]

I apologise if my post carried the inference that you had said otherwise. However, how meaningful is "pre-biotic chemistry"? If there was no biology subsequently, how was the chemistry "pre-biotic"? What counts as "chemical precursors to life"? amino acids? nucleobases? methane? water?

This has bugged me too (about the use of the term in reference to Titan, for example). I would think 'parabiotic' would be a better term -- the chemicals are those, or analogous to those (for a random example, different amino acids - but still amino acids -- or what have you) of life, but the processes of life are not present.

'Parabiotic' also doesn't tend to imply lesser complexity; it's not impossible that certain organic-chemistry systems on e.g. Titan might have life-like complexity while nonetheless not qualifying as 'life' (by our rather arbitrary definitions*). There are in fact hints of disequilibrium on Titan -- though it's too early to know if this is measurement issues or real IIRC.

*Even from purely Earthly examples it is not wholly self-evident where on the bacterium (clearly life) > virus > viroid > prion > crystal (clearly nonlife) continuum to draw the line; that we tend to include bacteria and exclude viruses is ultimately a subjective definition. I would argue that genetic inheritance containing hereditary information and the potential for evolution ought to be the defining feature of life, personally.

[Glom]

Has anyone tried to create a genesis tub?

[MaDeR]

There are in fact hints of disequilibrium on Titan -- though it's too early to know if this is measurement issues or real IIRC.

And even if this is real disequilibrium, it could be caused by currently unknown processes that have nothing to do with life (in other words, taking in account this process it would be in equilibrium). Of course, this case would be very interesting too.

it is not wholly self-evident where on the bacterium (clearly life) > virus > viroid > prion > crystal (clearly nonlife) continuum to draw the line

Erm. There is no line to draw. Life is continuum, not binary state.

[marsbug]

This has bugged me too (about the use of the term in reference to Titan, for example). I would think 'parabiotic' would be a better term -- the chemicals are those, or analogous to those (for a random example, different amino acids - but still amino acids -- or what have you) of life, but the processes of life are not present.

'Parabiotic' also doesn't tend to imply lesser complexity; it's not impossible that certain organic-chemistry systems on e.g. Titan might have life-like complexity while nonetheless not qualifying as 'life' (by our rather arbitrary definitions*). There are in fact hints of disequilibrium on Titan -- though it's too early to know if this is measurement issues or real IIRC.

*Even from purely Earthly examples it is not wholly self-evident where on the bacterium (clearly life) > virus > viroid > prion > crystal (clearly nonlife) continuum to draw the line; that we tend to include bacteria and exclude viruses is ultimately a subjective definition. I would argue that genetic inheritance containing hereditary information and the potential for evolution ought to be the defining feature of life, personally.

I agree with MaDeR on this, the only way to go is accept that the borders of life are fuzzy, and perhaps coin a new term for some phenomena, eg paralife? I wouldn't be entirely surpised if Titan had phenomena that, while not 'alive' were in the interestingly fuzzy area.

For example; Even inorganic crystals can self replicate, although they cannot evolve. A Titan based organic crystal that could self replicate, even if it could do no more than that, would be an interesting hint as to how self replication arises in complex organic chemical systems.

[RGClark]

But that was before the mass estimate was upped considerably by the Cassini fly-bys and tidal heating is quite dependent on the mass of what's being heated.
And it's tidal forces from Dione, not Saturn that is thought to be the main source of heat these days, seeing that it's face-locked to Saturn like our moon.

Just saw this today:

Cassini Finds Enceladus is a Powerhouse.
March 07, 2011

PASADENA, Calif. – Heat output from the south polar region of Saturn's moon Enceladus is much greater than was previously thought possible, according to a new analysis of data collected by NASA's Cassini spacecraft. The study was published in the Journal of Geophysical Research on March 4.
Data from Cassini's composite infrared spectrometer of Enceladus' south polar terrain, which is marked by linear fissures, indicate that the internal heat-generated power is about 15.8 gigawatts, approximately 2.6 times the power output of all the hot springs in the Yellowstone region, or comparable to 20 coal-fueled power stations. This is more than an order of magnitude higher than scientists had predicted, according to Carly Howett, the lead author of study, who is a postdoctoral researcher at Southwest Research Institute in Boulder, Colo., and a composite infrared spectrometer science team member.
"The mechanism capable of producing the much higher observed internal power remains a mystery and challenges the currently proposed models of long-term heat production," said Howett.

http://www.jpl.nasa.gov/news/news.cfm?release=2011-067



Bob Clark

[A.DIM]

Just saw this today:
Cassini Finds Enceladus is a Powerhouse.
March 07, 2011
http://www.jpl.nasa.gov/news/news.cfm?release=2011-067
Bob Clark

It's always fun to see turns of phrase like "than was previously thought possible" accompanying discoveries like this. It's clear we're wrong more than we're right about things...
Thanks!

[marsbug]

Can we have an Enceladus mission please?

[MaDeR]

Maybe. Maybe even we will not be senile old (wo)mens yet. Oh so optimistic. :/