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Libertarian28
2004-Dec-09, 10:12 AM
Is there something I've missed in 40 years of planetary study? People rave about the possibilities in oceans of Europa and Ganymede; but I find about zero speculation of life on the big two "gas giants" themselves. When and why has the scientific community dismissed the chance that even microbial life might abound there? Do phase diagrams exclude the possibility of liquid water on them? I think not and was under the impression that liquid water is a fact of life on both as evidenced by spectroscopic analysis, Shoemaker -Levy impact analysis, lightning in Jupiters clouds and come on, if there's water on those moons me thinks there should be quite a bit of it on "the gas giants". OK, can someone tell me if a water ocean is possible on the two or does it all turn to steam? And if it is possible might they then point out about where water might be found, say on top of the molecular helium mantle or sandwiched between the metallic hydrogen and the "rocky" core(I'm thankful the experts figure some wayward iron, tin, iridium, and even plutonium generator packs might have made the trip to Jupiter). Though they might go molten at the core.
I really resent the term "gas giants". Sure, the H and He are major constituents, but even the crudest cross-sections show these as going to fluid states in short depth. But the gas giant misnomer leads to a dismissive attitude concerning lifeforms. I suppose it is assumed that by the time one reaches a "fluid" layer the temps and pressures are to high for any marine -like critters. I would remind them of the fish seen at the bottom of the Mariannas Trench seven miles deep on Earth and the abundant lifeforms inhabiting the "black smokers" on our sea beds. So why no speculation of atleast floating organisms in the thick and colorful atmospheres of the giants? I do remember some artist's fanciful depiction of gas bag type floater's predating the various levels. And I remember 30 years ago in Sky and Telescope a mention that these colorful clouds must surely have organic chemistry at work. So again--why the total dearth of belief that even simple lifeforms aren't happening on such vast and complex planets?
If it's worth the effort to send the JIMO project to Jovian moons why not a slow probe,even a variable altitude balloon, with cameras, and WITHOUT THE PLUTONIUM GENERATORS, to King Jove ?
I respectfully seek some feedback on this subject--in particular some learned idea of whether or not one might find a warm, salty ocean beneath say 300 miles of roiling clouds. The atmospheric pressure might be quite high at such a sea level but not to the exclusion of pernicious and hardy lifeforms. Calamari anyone?

Kemp Woods
Chair-San Benito County CA. LP

Jakenorrish
2004-Dec-09, 11:19 AM
Hi Kemp,

I have been arguing previously that life could be present in ice craters on Mercury for all we know, so in response I would say agree with you and say why not? As our planet supports life, we always assume that conditions for life to be supported elsewhere would have to be similar to ours, but you make a very good point. Life can be found in the harshest of environments here. I'm sure that there is life present in even harsher places on Earth than we've discovered it so far. Just when we say 'No, that can't be possible' then someone comes along and discovers life in abundance in pools the strength of battery acid in volcanic craters!

Whilst it seems very unlikely that there is life in Jupiter or Saturn's (without forgetting the other gas giants) clouds, who knows? We certainly don't, and can't say one way or the other for certain. I'm sure we'll never find out though as the conditions there and radiation are too extreme for us to explore......

astromark
2004-Dec-09, 11:48 AM
Jupiter and Satern have interested me for the atmosphear hides the depths of liquide we suspect will be found. All that gas under all that presure... liquide and a solid core if you could ever get down to it. All a tad to hot and radiating far to much for us to go anywhere near. If I have understood what I have read. There is fusion or at least some form of energy being generated deep inside those gas giants. Thats a lot of presure and heat. I suspect the radiation may be the problem to the type of life we are familiar with. we shall wait and see.

Jakenorrish
2004-Dec-10, 09:34 AM
Totally agree with that. The radiation seems to be the biggest obstacle for not only life on Jupiter or Saturn, but life going anywhere near them!

Essel
2004-Dec-10, 12:53 PM
Hello Libertarian28,

Radiation levels on Saturn are far lower and there is definite possibility. However, technically are we prepared to take a plunge on the gas giants and still capture some meaningful data?

While everyone says that water is necessary for life, I do not completely agree. A chemical that is available in solid, liquid and gaseous form in a planet or a satellite can form complex chemicals under different set of pressure and temperatures.

While everyone says that 100 K temp on Titan is too cold to hold a lifeform and compare it with Earth 3.8 Billion years ago, I disagree with that. I think such a vast reserve of hydrocarbons for such a long time could evolve lifeforms independent of water. The fluid flowing through the bodies of such organism could be methane, all you know.

I also disagree with Mars being declared sterile. I think life can be found there if enough research is conducted. For mars I suggest we look for the sources of Methane traces. Here also I suggest we look for water based as well as water independent lifeforms. The best place to look for lifeforms in mars would be at the depth of the trenches and canyons. I wonder why did we not land our probes there so far? Atmospheric pressure, temperature and radiation levels could be favorable there.

I think radiation overdose is the only no-no for life. However, life needs energy and that can come from controlled dosage of radiation, which is most abundant energy source in the universe.

The above are my personal views only.

Cheers

Jakenorrish
2004-Dec-10, 02:24 PM
Yeah, its a bit off the subject, but if we can rule out volcanic activity on Mars, then there's only one other explanation for the methane traces. Fingers crossed!

Bobunf
2004-Dec-10, 08:48 PM
The Galileo Probe stopped transmitting data about 600 kilometers after entering the atmosphere. The temperature was 153 degrees C. I don't know of any life that exists at 153 degrees C, no matter how extreme, and the temperature will get much hotter as one goes lower into the Jovian atmosphere.

I think that means any life on Jupiter would have to exist in a region a few hundred kilometers deep, and with extreme temperature variation even within this range, no liquid water, lots of very powerful wind currents and nasty radiation.

I think I'd rather bet on a nice warm, salty ocean with gentle currents and not much temperature variation, protected from impacts and radiation by kilometers of ice and rock.

If we're ever going to do any further exploring of the outer planets, we'll probably need lots of plutonium. Even on Mars, not using plutonium really limits the life and activities of the rovers that are currently functioning on Mars. Reduce solar insolation by 92% around Jupiter and it gets pretty hard to do anything with solar.

Saturn get less than a third as much sunlight as Jupiter, and it gets worse and worse the further out one goes.

Bob

Jakenorrish
2004-Dec-12, 02:25 PM
It does seem extremely unlikely, but never say never!!

Nyrath
2004-Dec-13, 07:08 PM
Originally posted by Bobunf@Dec 10 2004, 08:48 PM
The Galileo Probe stopped transmitting data about 600 kilometers after entering the atmosphere. The temperature was 153 degrees C. I don't know of any life that exists at 153 degrees C, no matter how extreme, and the temperature will get much hotter as one goes lower into the Jovian atmosphere.
Of course, no life-as-we-know-it could survive 153 degrees C. But life-as-we-don't-know-it might.
The Good Doctor Isaac Asimov speculated (http://www.projectrho.com/rocket/rocket3aa.html#notasweknowit) that a metabolism based on fuorocarbons dissolved in molten sulfur could survive up to 445 degrees at one atmosphere of pressure. In theory, of course.

Betelgeuse
2004-Dec-14, 04:08 PM
Originally posted by Nyrath@Dec 13 2004, 07:08 PM
Of course, no life-as-we-know-it could survive 153 degrees C. But life-as-we-don't-know-it might.
This is absolutely correct! It really annoys me when people don't think outside the box and meerly assume that any existing intelligent or even in the simplest form of bacteria will be how we know it! People ponder and moyder that "life won't be able to exist on any of jupiter or saturn's moons because temparatures are too high/low" - life can adapt to it's surroundings.......

ChromeStar
2004-Dec-14, 06:33 PM
reply to original post

Hi Libertarian28

i think it's important to remember that something is'nt true until proven so!

also based on the little bit we do know of jupiter and saturn we can deduce that life does'nt exist there.

however given life's resilience here on earth who says it is'nt possible!

Jakenorrish
2004-Dec-15, 09:26 AM
It seems we're all agreed on this one. It is very unlikely that there is life there, but it throws the next question which begs an answer in to the melting pot which is:

How do we find out if there is life on any of the gas giants?

Erimus
2004-Dec-16, 01:31 AM
The late Carl Sagan and Arthur C. Clarke have speculated about aerial life on Jupiter and other gas giants; see Sagan's Cosmos and Clarke's award-winning novella "A Meeting with Medusa."

I however, have been skeptical about the prospects of life on Jovian planets for two major reasons:

1.) The atmospheres of these planets seem to be very turbulent; I think it's doubtful that any interesting prebiotic molecules last long before they're cycled down to atmospheric layers that are hot enough to destroy them.

2.) The deeper layers of the gas giant planets are extremely hot; Jupiter and Saturn's liquid hydrogen layers are probably hundreds, if not thousands of degrees K. Organic life has its limits.

3.) What may seem baseless assumptions about life--for instance, assuming Earth-like limits for biology--is a result of the fact that we only have our kind of life to go on. Exotic forms of life may not be impossible, but based on what we know about biochemistry, most of these forms are improbable. Limiting examples to terrestrial-type life may be narrow-minded, but it gives exobiology a comfortable and known place to start from.

Jakenorrish
2004-Dec-16, 09:16 AM
Hi Erimus,

I agree, whilst I think it is highly improbable that there is life in the clouds of the gas giants, it seems that whenever we set a boundry based on what we know about biochemistry, we seem to find that we underestimated life's ability to survive and adapt to the seemingly impossible.

ChromeStar
2004-Dec-18, 07:06 AM
Hey Jakenorrish

there was a documentary on the discovery channel in South africa about life on other worlds it focussed on life on jovian like planets mars- earth like planets with extreme gravity and so on.

maybe you saw it?

qraal
2004-Dec-20, 01:29 AM
Hi UT

In answer to the first post the equations of state for Jupiter and Saturn imply - and the heat leakage from both bares it out - that they are far, far too hot for any water to be liquid in any form but cloud droplets. In fact Jupiter might be too hot (~ 30,000 K) to have a differentiated core, instead the whole mass is a convecting fluid. Saturn does have a core but at the calculated temperature of ~ 15,000 K it can't be considered "solid" in any meaningful way.

Neptune and Uranus were thought, until recently, to have liquid water/ammonia oceans, but better physical models have ruled that out. A number of models have been made of very large "ocean" planets - Poseidons is the suggested name - but with an interesting result. To have cool enough conditions for a stable ocean there is a maximum depth before the oceans turn into high-pressure phases of ice - initially Ice VII, then denser phases lower down. A Poseidon with six Earth masses and half its mass in water has a maximum radius of ~ 2.0 Earth, with a gravity of 1.54 gee. The ocean is about ~ 100 km deep with a massive ice shell surrounding the core and mantle some 4850 km thick!

So you can forget Isaac Asimov's old models of deep, deep oceans in the Jovians - they're too hot and water doesn't stay liquid beyond ~ 22,000 bar pressure.

qraal

GOURDHEAD
2004-Dec-20, 03:12 PM
Thanks graal, that's an interesting data set.

GOURDHEAD
2004-Dec-20, 03:34 PM
To have cool enough conditions for a stable ocean there is a maximum depth before the oceans turn into high-pressure phases of ice - initially Ice VII, then denser phases lower down. How much evidence is there that sufficient oxygen, or water, existed in the regions where Uranus and Neptune formed to provide several Earth masses of water there. Is the presence of all those "snow balls" masquerading as moons and Kuiper belt objects sufficient evidence?

It's nice to know we have a source for the water (mass) needed to terraform Mercury and Mars. Enough jobs to maintain employment at 100%! We may have to cancel vacations!

qraal
2004-Dec-23, 02:54 AM
Originally posted by GOURDHEAD@Dec 20 2004, 03:34 PM
How much evidence is there that sufficient oxygen, or water, existed in the regions where Uranus and Neptune formed to provide several Earth masses of water there. Is the presence of all those "snow balls" masquerading as moons and Kuiper belt objects sufficient evidence?

It's nice to know we have a source for the water (mass) needed to terraform Mercury and Mars. Enough jobs to maintain employment at 100%! We may have to cancel vacations!



The main evidence for water and similar molecular mass compounds in the Snow Giants (Cool name, huh?) is their densities. For their current radius they must be mostly "ices" (i.e. water, methane and ammonia ), albeit hot fluids rather than solid crystal because of the core temperatures. If they were mostly hydro-helium they would be fluffy like Saturn (density ~ 0.7) but they're slightly denser than water (1.32 and 1.64, for Uranus and Neptune respectively.)

They might have shared a common origin with the Snow Balls, though interestingly the long period comets from the Oort Cloud have a different mix of frozen gases and must've formed from around Jupiter's orbit. There are a few different theories of origin for the planets that it's hard to know where to start.

Personally I think the Solar Nebula Theory (SNT) is doing a pretty decent job of explaining what we see, but the Capture Theory (CT) and the Modern Laplacian Theory (MLT) have some good points too.

In the SNT the cometoids formed as unaccreted planetesimals alongside the planets which were then scattered - the ice moons formed from mini-Nebulas around each Big Planet.

The CT forms the ice moons the same way, but the cometoids are from a planetary collision between two Jovians, A & B - the silicate cores became Earth and Venus, while the outer mass of volatiles provided a cloud of debris that collapsed into the cometoids and asteroids. Depth within the original planets determined how far the debris was flung, hence heavier material is closer than the lighter stuff to the Sun.

The MLT forms the Asteroid Belt and the Kuiper Belt as distinct rings separate to the planets themselves, though each Big Planet probably had material condense in its orbit that was later scattered. Most of the moons are from rings shed by each planet and are a chemically identical to the primary until the hydro-helium blows away.

qraal

eburacum45
2004-Dec-23, 10:16 AM
The problem I have with life on gas giant planets is that there is nowhere stable enough for it to originate.
However if we imagine a gas giant with a large watery moon in orbit around it the moon itself might hold a stable enough environment for life to develop;

then given a number of large meteor impacts on the surface of those moons then extremophile organisms might get blasted into space and eventually findtheir way on to the gas giant and colonise the upper atmosphere.

Call it localised panspermia.

trevorsproston
2004-Dec-23, 07:42 PM
I've mentioned this on another forum, but it seems appropriate here.

Read "Wheelers" by Jack Cohen and Ian Stewart - I think you'll all find it interesting.

Nereid
2005-Jan-12, 06:32 PM
Imagine you are the director of NASA's or the ESA's extraterrestrial life team (and that you don't have to deal with any politics, personnel management issues, etc ... just SETI). You have a fixed budget (we'll look at that in more detail in a minute), you are fascinated by the possibility of extraterrestrial life, and you have a team of really bright, energetic people working for you.

Where, among the myriad competing ideas on how best to spend your fixed budget, would you put searching for life on the gas giants? Would it be top of your list? Third?

Suppose 'look for life on Jupiter or Saturn' made it through the review committee (which you established to avoid charges of ignoring good ideas). How would you set about implementing the committee's recommendation? What sorts of results would lead you to conclude 'yep, there's life on Jupiter'?

Jakenorrish
2005-Jan-13, 09:11 AM
Hi Neirid,

you are of course absolutely right. I think that the next boundary of space exploration will happen when we take the government, and in that case taxpayers money out of the equation, and private enterprise leads the way. I don't think for a minute that anybody will be searching for life on Jupiter or Saturn any day soon, but it is interesting to speculate about it!

cheers,

Jake

GOURDHEAD
2005-Jan-13, 02:53 PM
Where, among the myriad competing ideas on how best to spend your fixed budget, would you put searching for life on the gas giants? Would it be top of your list? Third? ......How would you set about implementing the committee's recommendation? What sorts of results would lead you to conclude 'yep, there's life on Jupiter'? It would be well down on the list until we get more competent at space exploration. The expense of such an effort and its plan ahead time are formidable. A start of the definition of the system required to accomplish such a mission is described here (http://hometown.aol.com/malcolmbmcneill/InterstellarTransportationExplo.html). One would expect to find life in the upper 10% of the atmospheres of the giants, if at all, but should be prepared to explore the upper 40%. The robustness of a system capable of conducting such exploration should be capable of sustaining humans in orbit about the giant while controlling robotic craft sampling the atmospheric constituents. This will require substantial amounts of energy (radiated to the site from near the sun) to sustain the crew and power the robotic craft. We are at least 200 years from launching a system of the required robustness. Also, opening this level of Pandora's box should only be done by those competent of dealing with unimaginable adverse consequences..i.e., robust robustness.

The type of results leading to the conclusion that there's life there:
They devoured the robotic craft.
They attacked the orbiting ship.
Samples returned to the orbiter emulate Earth life.

ashok_bitsboymech
2005-Jan-28, 07:53 AM
hai guyz,
can anyone think tht why some palnets are much larger and some or not.why it would have happens os?ya i read tht the sun is nearing the earth.it wil destroy the closer planets nearer to it.as this happened tht in the sun itself there would be more got destroyed billion yrs ago.so there would be some more planets b4 mercury and in those there would hv been some planets tht provides existence of life .so life would have been started frm some planets after tht earh and in furure may be jupiter can bcom as a palnet providing for human's survival.thos ewho want to join with me abt this topic can mail plz me.and we can start our research regarding the related topics.
bye
awaiting 4 ur reply.

CyprusX
2005-Feb-06, 08:11 PM
Originally posted by Jakenorrish@Dec 10 2004, 09:34 AM
Totally agree with that. The radiation seems to be the biggest obstacle for not only life on Jupiter or Saturn, but life going anywhere near them!
Radiation may very well be a problem for life on this planet, but should we assume that there is only one type of life. What if other forms of life on other planets adapted to their environment like life did here on Earth.

Jakenorrish
2005-Feb-08, 12:39 PM
Fair point that. If they can find life 10 k down in the ocean at 1000 g's or whatever it is, then why not on the gas giants?