Venus vs Titan: which is more likely to support life?

[magnemoe]

3 minutes ago, kerbiloid said:

As Titan still has huge amounts of hydrocarbons and ammonia, probably they had never boiled.
If Titan has a warm and salty subsurface ocean, can't it be rich with hydrocarbons or so?

So, chances of life:
Venus: 0.
Europa: 0+.
Titan: 0+ Premium.

Titan exploration should be the main and central aim of SolSystem exploration. Not Mars or Europa.

An problem with an subsurface ocean on large ice moons is that you would get ice on the bottom because of the high pressure of hundreds of km with water.
That ice layer would probably block off access to volcanic vents and minerals 
 

[K^2]

12 minutes ago, kerbiloid said:

Titan exploration should be the main and central aim of SolSystem exploration. Not Mars or Europa.

Eh. Mars makes sense. It's close. We can do all sorts of things with it at a fraction of the cost. If nothing else, it's good space exploration experience. But Europa does seem like a waste.

I also like Venus for hab potential, but we're talking completely different tech level and time scales here, so it's a different story.

P.S. Just to clarify, none of these are the "You fools!" kind of 'wrong' targets. We'll get something useful out of exploring almost anything, and we should be doing more exploration period. But of what we know to be out there, Titan comes up to the top of the list.

Edited September 22, 2016 by K^2

[kerbiloid]

1 minute ago, magnemoe said:

An problem with an subsurface ocean on large ice moons is that you would get ice on the bottom because of the high pressure of hundreds of km with water.
That ice layer would probably block off access to volcanic vents and minerals 

This problem should be common for any ice moon: Europa, Enceladus and Titan.
So, chances of Titan are at least not less than chances of Europa and so. They look the highest of those lowest.

[lajoswinkler]

If presented with these two choices, Titan, absolutely, even though chances for it are very low. There has to be liquid under its crust and that liquid has to be an aqueous solution of various compounds.

Venus has been thoroughly dried up like a plum because of its extensive volcanism. Even though there has to be water in it, it's bonded to the rocks just like in Earth. It is a form of subsurface ocean, but it's not free water or pockets of it. Venus is way larger than Titan, remember that.

[Matuchkin]

I'm thinking that, if anything lives on Venus, it's going to be some insane type of Archaebacteria that drifts like pollen and uses mitosis to reproduce. As for Titan, at least it has some organic material.

I'm gonna go for Titan.

Edited September 22, 2016 by Matuchkin

[Beowolf]

On 9/21/2016 at 0:07 PM, todofwar said:

As an analogy, I wouldn't test my luck against someone with a gun or someone with a knife, but if I have to choose I'll go against the person with a knife. 

I certainly have no personal experience, but from my reading, that was the wrong choice. When on the defensive at melee range, the books say knives are much deadlier than handguns.

[mikegarrison]

Pressure in liquid is no big deal for life as we know it. Liquid is incompressible, so the density remains approximately the same. And as long as the pressure inside the cell walls matches the pressure outside -- no problem. Even for humans, extreme pressures are only a problem because we breathe gasses.

[Hypercosmic]

We (well, at least for Titan-genesis) all know about Titan being clearly better place for life to origin and evolve.

But Venus has its cloudtops, which is the most Earthlike location in Solar System apart from Earth itself. 343K, 1 atm pressure, some acid neccessary for life, and trace of water vapor. And panspermia from Earth, and so on.

I still vote for Titan though.

[Diche Bach]

On 9/21/2016 at 4:36 PM, Jeb1969 said:

Life on venus is quite absurd the surface temperature is nearly 470 degrees centigrade (743.1 degrees kelvin)  or 878 degrees fahrenheit, atmospheric pressure is a whopping 92.6 atmospheres (9382.69 kilopascals) besides sporting high temperature Venus has an atmosphere of Carbon Dioxide and Various Sulfuric Gases, which precipitates as a  crude form of sulfuric acid. Due to possible Volcanism on the surface, and the greenhouse effect lastly the upper atmosphere of venus is electrostatically charged and gives of large amounts of electrostatic discharge in the form of lightning. Basically Venus is the astronomical equivalent of hell. 

Maybe it is where demon prions live?

Have to admit, my notions about what might be out there have been transformed a bit these past few months since I got active on this site and watching science Youtubes more often. I had not heard they found glycine from the tail (corona?) of a comet, and that strikes me as pretty stunning. How the hell did that stuff GET THERE!

I've got an old book here on my shelf: The Touchstone of Life (1999) by Werner Loewenstein and while it has been many years, the understanding I developed from it and other (apparently out-dated) materials while I sampled this area a bit in grad school was that: the conditions for life to spontaneously begin depends on a "thick soup" of organics, and the appearance of organics may well have depended on a very special cocktail, shaken not stirred, at exactly the correct temperature, pH, etc., etc.

Seems like those generalizations can pretty much be tossed out the window if balls of rock and ice that live most of their time far outside the orbit of Jupiter are literally "coated" in layers that include glycine. If there is glycine, then most of the organic molecules that are central to life as we know it might well be "out there" spilled all of the solar system and that is a very different model than the one I learned, and which appears to be getting progressively more questionable as a result of contrary evidence each year.

My "gut" is: no life out there anywhere but Earth, but then  . . . glycine coated comets . . . maybe there is life all over the damn place and in situations which have been or are in someway favorable, maybe it actually persists, undergoes adaptive radiation and something like actual ecologies evolve.

[kiwi1960]

define "life"

 

then maybe we can answer.

[mikegarrison]

2 hours ago, kiwi1960 said:

define "life"

 

then maybe we can answer.

Yes, there's the rub. About 98% of the time, people mean "self-replicating organisms based on hydrocarbon/water chemistry the same as on Earth". If "life" just means "anything capable of self-replication" then the answers change immensely.

[kiwi1960]

3 hours ago, mikegarrison said:

Yes, there's the rub. About 98% of the time, people mean "self-replicating organisms based on hydrocarbon/water chemistry the same as on Earth". If "life" just means "anything capable of self-replication" then the answers change immensely.

Yes.... as a Star Trek fan, we know there is silicon based life.... LOL

I think we just need to keep looking, if we find a candidate, we can decide if its "life"... and then take it from there. I agree that if we are narrow minded, then we are defeatign the whole purpose of searching for life... put another way..... "its life.... but not as we know it!"

 

[Diche Bach]

Well, I hope we can agree that a "A comet with an icing of glycine [I'm a poet and didn't know it!] does not life mean." But it is rather fascinateeng.

I still would like to hear how the brightest minds in those research areas hypothesize how that stuff _got there_.

[Matuchkin]

I like how the SAGE lander components were put in water to simulate Venus's lower atmosphere, and in a wind tunnel to simulate the higher atmo.  

Edited September 25, 2016 by Matuchkin

[todofwar]

2 hours ago, Matuchkin said:

I like how the SAGE lander components were put in water to simulate Venus's lower atmosphere, and in a wind tunnel to simulate the higher atmo.  

Well, now there's the Glenn Extreme Environments Rigg, which will do a much better job simulating the surface

[magnemoe]

13 hours ago, mikegarrison said:

Yes, there's the rub. About 98% of the time, people mean "self-replicating organisms based on hydrocarbon/water chemistry the same as on Earth". If "life" just means "anything capable of self-replication" then the answers change immensely.

Life is something who has an metabolism and reproduces. metabolism to exclude virus, prions and also stuff like computer viruses and simulations even crystals.
An von neuman machine would technically be alive. We don't even have theoretical models of something else who is not carbon/ water based.
Main issue with low temperature chemistry is that things would be slow, at 1/100 of earth life chemistry you would still be at the early life stage, nothing as complex as bacteria. 
Now with high temperature chemistry who we have an better handle on is it any way we could get something self replicating? downside of exotic chemistry is that lots of it is exotic. 
You will need common materials, you will not get an ocean of liquid lead as lead is rare.

 

[Diche Bach]

On 9/22/2016 at 7:52 AM, todofwar said:

I think that's taking it a bit far. Titan has a small chance of harboring life, but that is like the odds of us finding bacteria on a comet. Possible, sure, but extremely unlikely. Saying Titan is the most important place to look for life is like saying the moon is the most important because it would show how life can develop in vacuum. 

And I can't emphasize how terrible a solvent methane is enough. It's not just bad at polar compounds, it's bad at pretty much everything except other hydrocarbons. How will you get electrochemistry going without electrolytes? How will you get energy transfer without electrochemistry? How will you get self replication without energy?

Until I learned that they found glycine spraying out of an ablating comet a few years back, I would have agreed with you. But the fact that thing is apparently "coated in a layer of glycine" seems like a total game changer to me.

[Matuchkin]

7 hours ago, todofwar said:

Well, now there's the Glenn Extreme Environments Rigg, which will do a much better job simulating the surface

What, an acidic arc-furnace? Sounds pleasant.

Edited September 26, 2016 by Matuchkin

[todofwar]

5 minutes ago, Matuchkin said:

What, an acidic arc-furnace? Sounds pleasant.

Basicall an autoclave. Pressure vessel also capable of achieving the temps on the surface, and careful control of the gasses to match the Venusian atmospheric composition. And can be set for different pressures and temps for different altitude simulations. They recently got it up and running.  

[Diche Bach]

On 9/22/2016 at 8:16 AM, K^2 said:

You want a solvent that's bad at everything. Because if you have a strong solvent, it will tear apart any bonds you could possibly use to organize your complex molecules at 90K without everything freezing solid. That includes the solvent, by the way.

You can do electrochemistry without ions. It sucks in comparison, and your energy storage is going to be ridiculously inefficient, but so is your energy flow to begin with, and so is the rate of every single process. And something is breaking down acetylene, releasing the stored energy, so it's clearly possible. Making use of that energy is the trick. Do I have any idea how? Nope. But I wouldn't have called ATP synthesize, either.

And it's all about the expectation on the return. A product of utility of discovery times it's likelihood. Life on mars has high likelihood, but tiny utility. We already know Terrestrial life could survive on Mars. Rest is academic. Life on an asteroid would be groundbreaking, but it's ridiculously unlikely to begin with and multiplied by our odds of finding the right asteroid. So again, very poor expectation value. Worse, we learn absolutely nothing but not finding life there. That's what we expect. Life on Titan has the right math going for it. It's certainly feasible. We see indirect evidence we expect to find, which is a good first indication. And life on Titan matches optimistic range of expectation for how life develops. Not finding life there would already be useful just to cross off the most optimistic of our expectations. But finding it there would be revolutionary and the odds of it are distinct from zero.

Think of it this way, sending a mission to Titan is like buying a lottery ticket where you are guaranteed to win at least the cost of the ticket. That would be the outcome of the study that finds no life there. It's still useful. This is the disappointing outcome, for sure, but you lose nothing. And the possibility of winning the jackpot, while somewhat remote, is definitely there, so it's just stupid not to go for it.

This is in contrast to every other destination in this Solar System. Mars is sort of a sure thing, we'll definitely get good mileage out of it, but unless we find ruins of alien civilization there, which we won't, it's not going to be anything revolutionary. And everywhere else we can go, we risk finding absolutely nothing of interest other than filling in a few checkboxes in our knowledge of the system. Titan has everything. Guaranteed payout and a chance for something great. It should be the highest priority target for this century.

Overall an interesting and well-said post, but that one part I bolded I found a bit . . . erm rash. But then may be you know something I don't. Can you elaborate on that point?

I would have to disagree with the general philosophy you seem to be proposing in the latter half of your post, which seems to break down to "the discovery of extra-terrestrial life is the most important consideration for space exploration." I disagree. While I think that various well-conceived missions intended on focusing on clues about the origin and/or extent of life in our solar system are extremely important and well-conceied (Rosetta, Stardust, etc.), but I would have to say that these mission necessarily should be considered merely "good fillers" for the periods when economies of scale (else political climates) make building the foundations for resource prospecting, extraction and utilization: undertakings which may have real and dramatic effects on the economic and general well-being of humanity.

If I had to pick between either Titan or Venus, I'd pick: Asteroid Prospecter observatory. Not sure how that would work or if it even would work but it strikes me as the nest most impotant thing . . . with proper mineral prospecting of the moon perhaps taking first place.

[Kryten]

3 hours ago, Diche Bach said:

Until I learned that they found glycine spraying out of an ablating comet a few years back, I would have agreed with you. But the fact that thing is apparently "coated in a layer of glycine" seems like a total game changer to me.

You can't make a living organism out of amino acids, so that's not really relevant. Best guess we've got is that the earliest life used RNA, and still would've needed something else to make a membrane.

[K^2]

 

1 hour ago, Diche Bach said:

I would have to disagree with the general philosophy you seem to be proposing in the latter half of your post, which seems to break down to "the discovery of extra-terrestrial life is the most important consideration for space exploration." I disagree. While I think that various well-conceived missions intended on focusing on clues about the origin and/or extent of life in our solar system are extremely important and well-conceied (Rosetta, Stardust, etc.), but I would have to say that these mission necessarily should be considered merely "good fillers" for the periods when economies of scale (else political climates) make building the foundations for resource prospecting, extraction and utilization: undertakings which may have real and dramatic effects on the economic and general well-being of humanity.

I'm not going to insist on it as "one true philosophy" for space exploration. But there are two factors here, philosophical and practical. Discovery of life on Titan makes it an almost certainty that extraterrestrial life is abundant in the Universe. The philosophical implications are "We are likely not alone." There either are, were, or will be other sentient beings among the stars. One may argue that it already seems likely, but with a datum of one, which is effectively zero due to anthropic principle, we can't really draw any conclusions. Having two points of data, we can make a strong statement about this.

Second is practical. If life is found on Titan, Fermi Paradox suddenly becomes that much more important. It tells us with extreme confidence that origin of life isn't the Great Filter. This still doesn't say with certainty if the filter is ahead of us or behind, but it just shot down a likely candidate for the past, and it's a red flag at the very least. When survival of the species is on the line, knowing this information as early as possible could be crucial for us avoiding whatever calamity we might be heading for.

There are other reasons why space exploration is matter of species survival in the long term, but exploration of Titan would still further these goals. As such, I conclude that exploration and discovery of life on Titan would be the most important scientific achievement of Human kind to that point. Whereas exploration of Titan with no discovery of life would simply be an important step in space exploration in general. And centuries down the line, hopefully, we'll make bigger and more important discoveries to which Titan was but a stepping stone.

[Hypercosmic]

On 9/25/2016 at 2:28 PM, mikegarrison said:

Yes, there's the rub. About 98% of the time, people mean "self-replicating organisms based on hydrocarbon/water chemistry the same as on Earth". If "life" just means "anything capable of self-replication" then the answers change immensely.

Then self-replicating patterns will be life.

 

Certainly it isn't. Life requires many thing.

1. Homeostatis (Maintaining internal environment.)

2. Organization (Made from one or more cells.)

3. Metabolism (Making energy.)

4. Growth

5. Adaptation

6. Respond to stimulati

7. Reproduce

 

Back on topic:

The best bet: Mars and Venus cloud tops (Proximity to Earth makes panspermia easy. Also, Venus has lightnings, which makes abiogenesis easier.)

Another good bet: Europa and Enceladus (Both are known to have liquid water under the surface)

The last safe place: Luna (You know, panspermia might even bring Earth life out and into lunar poles, where ices exist. Now it's up to time we might or might not discover. Added for fun.)

A Muuh's favorite world: Titan (Plenty of hydrocarbons and food LITERALLY raining from the sky, exotic biochemistry make it possible. They would live off azotosomes.)

One weird bet: Jupiter and Saturn (I know it sounds bizzare, but considering the nearby Europa or Enceladus. If life evolved early enough and panspermia brought life from the then molten Europa or Enceladus, which the latter one is probably already solid, to Jupiter or Saturn, it might even have life! I don't really like this idea, though.)

The dark horse: Space itself. Self-replicate lifelike patterns there could evolved into something living, but they probably have a rough time with metabolism thing.

 

In the end, I would like to say that even life might be plenty, intelligent life aren't. Enjoy your intelligence in a good way, for sake of those who aren't!

[magnemoe]

2 hours ago, K^2 said:

 

I'm not going to insist on it as "one true philosophy" for space exploration. But there are two factors here, philosophical and practical. Discovery of life on Titan makes it an almost certainty that extraterrestrial life is abundant in the Universe. The philosophical implications are "We are likely not alone." There either are, were, or will be other sentient beings among the stars. One may argue that it already seems likely, but with a datum of one, which is effectively zero due to anthropic principle, we can't really draw any conclusions. Having two points of data, we can make a strong statement about this.

Second is practical. If life is found on Titan, Fermi Paradox suddenly becomes that much more important. It tells us with extreme confidence that origin of life isn't the Great Filter. This still doesn't say with certainty if the filter is ahead of us or behind, but it just shot down a likely candidate for the past, and it's a red flag at the very least. When survival of the species is on the line, knowing this information as early as possible could be crucial for us avoiding whatever calamity we might be heading for.

There are other reasons why space exploration is matter of species survival in the long term, but exploration of Titan would still further these goals. As such, I conclude that exploration and discovery of life on Titan would be the most important scientific achievement of Human kind to that point. Whereas exploration of Titan with no discovery of life would simply be an important step in space exploration in general. And centuries down the line, hopefully, we'll make bigger and more important discoveries to which Titan was but a stepping stone.

I don't see how Fermi paradox will be affected by life on Titan. Even if its life on it and even if the life type on Titan was common on Titan type planets. 
Problem is that biochemistry on Titan would be very low power and probably slow, hard to get intelligence or even large animals. 
Yes indirectly having life by an alternative biochemistry indicates it might be even other types.
Now looking for exoplanets with an oxygen atmosphere will be more relevant for Fermi paradox, planets with photosynthesis / planets suitable for life would answer how common life is
 

[Steel]

41 minutes ago, magnemoe said:

I don't see how Fermi paradox will be affected by life on Titan. Even if its life on it and even if the life type on Titan was common on Titan type planets. 
Problem is that biochemistry on Titan would be very low power and probably slow, hard to get intelligence or even large animals. 
Yes indirectly having life by an alternative biochemistry indicates it might be even other types.
Now looking for exoplanets with an oxygen atmosphere will be more relevant for Fermi paradox, planets with photosynthesis / planets suitable for life would answer how common life is
 

You're misunderstanding the Fermi Paradox. It's not just about whether or not there is life, but why we don't see more of it if it exists.

One of the main solutions is to posit a "great filter" (as mentioned earlier by K^2) which is a point in the evolution of life where the vast majority of life forms that come into being don't get past. If we find life on Titan, we at least know that the great filter isn't simple getting life started in the first place, which means that its more likely that the great filter is ahead of us. 

There's a waitbutwhy article that's really good if you want to read more about the great filter 

Edited September 26, 2016 by Steel