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elizabeth25
2011-Dec-06, 01:41 PM
Dont know if there is already a thread for this

http://uk.news.yahoo.com/nasa-confirms-super-earth-could-hold-life-020348621.html

second link

http://uk.news.yahoo.com/scientists-discover-earths-twin-planet-010419253.html

eburacum45
2011-Dec-06, 02:07 PM
We are discussing this one on this thread
http://www.bautforum.com/showthread.php/58157-Interesting-extrasolar-planet-discoveries?p=1966258#post1966258
but if you like, we could use this thread for a discussion of the chances it holds life.

The good news is, it is around the right temperature, assuming it has the right mix of gases in the atmosphere.

The bad news is, it is probably at least 10 times as massive as the Earth, so it won't be very Earth-like. Perhaps there is life present, but it will be nothing like life on our planet. It might hold a population of prebiotic replicating molecules, a population of algae or bacteria that may or may not resemble those on Earth; it might have a population of fish-like creatures, or low, strong, high-gravity-adapted land animals. If the atmosphere is dense enough it could have a population of flying or 'air-swimming' creatures.

Or something else entirely, or nothing. It certainly does not hold anything resembling a human.

iquestor
2011-Dec-06, 02:23 PM
Questions:

do we know how higher gravity would affect bacteria growth -- does higher gravity necessarily preclude the genesis of cells?

I dont think they know the actual size yet, and so we dont know radius, so we cannot calculate gravity yet.

I wonder when they can start attempting to characterize if it has an atmosphere?

Ilya
2011-Dec-06, 03:02 PM
If by "higher gravity" you mean 2-5 times Earth's, it does nothing to bacteria. Microbial culture have been grown in cetrifuges at hundreds of gravities.

Large animals, especially on land, are a different matter.

eburacum45
2011-Dec-06, 03:11 PM
Radius is the only thing they know, and it is known with quite some confidence; 2.4 x the radius of Earth.
Assuredly bacteria would not be affected by high gravity, but other factors in the environment would dictate whether bacteria evolve at all. If it is a waterworld the local environment might be too dilute to allow abiogenesis. On the other hand abiogenesis might happen elsewhere in the system and life could be transferred to this planet and thrive. Or the local microbiota might not resemble Earth species at all.

Other possibilities; a living ocean, full of specialised forms that cooperate together to form a superorganism; or a mechanical ecosystem, formed from organic self-replicating probes sent there millions or biollions of years ago. There are many others.

IsaacKuo
2011-Dec-06, 04:35 PM
The bad news is, it is probably at least 10 times as massive as the Earth, so it won't be very Earth-like. Perhaps there is life present, but it will be nothing like life on our planet. It might hold a population of prebiotic replicating molecules, a population of algae or bacteria that may or may not resemble those on Earth; it might have a population of fish-like creatures, or low, strong, high-gravity-adapted land animals. If the atmosphere is dense enough it could have a population of flying or 'air-swimming' creatures.

Or something else entirely, or nothing. It certainly does not hold anything resembling a human.

I don't see how you could make such broad conclusions. It's possible that it has an Earth-like atmosphere, with Earth-like life. The gravity level may be higher, but maybe only 3 gees or so.

Roughly speaking, height limits would be proportional to gee level, for land plants and animals. There are plenty of primates three times shorter than us. So an alien with similar proportions to us is possible--just one third the scale.

Paul Wally
2011-Dec-06, 04:43 PM
The fact that the planet is more massive than Earth could mean that it holds one or two moons.

eburacum45
2011-Dec-06, 04:46 PM
Primates originally evolved as tree-climbing frugivores. In an ecology adapted to an environment with 2.5 to 3 gees, tree-climbing frugivores would be quite remarkably different to Earth examples. Trees themselves would be very different; so, indeed would fruit. At the end of such a chain of difference, it is possible that one might end up with some sort of stunted humanoid, but the possibility seems very remote.

So an alien with similar proportions to us is possible--just one third the scale. And one third the encephalisation, unless it devotes absurd amounts of energy to supporting the head and blood supply thereto.

Githyanki
2011-Dec-06, 05:00 PM
Why are we assigning evolutionary paths on a world we just heard of and know very little about it.

First question is, how old is the system? If it's only a billion years old, you're not going to find much there most likely but bacteria.

eburacum45
2011-Dec-06, 05:12 PM
I'm not assuming; I'm speculating. Different thing.

IsaacKuo
2011-Dec-06, 05:19 PM
Primates originally evolved as tree-climbing frugivores. In an ecology adapted to an environment with 2.5 to 3 gees, tree-climbing frugivores would be quite remarkably different to Earth examples. Trees themselves would be very different; so, indeed would fruit.
Why would trees be very different? They might "only" grow to 30m high, but the basic structures and mechanisms could be the same.

And one third the encephalisation, unless it devotes absurd amounts of energy to supporting the head and blood supply thereto.
Why? The encephalisation could be the same, given the alien is 1/3 the height of a human. The pressure difference from head to toe is the same. The required support material scales properly.

iquestor
2011-Dec-06, 05:33 PM
Radius is the only thing they know, and it is known with quite some confidence; 2.4 x the radius of Earth.
Assuredly bacteria would not be affected by high gravity, but other factors in the environment would dictate whether bacteria evolve at all. If it is a waterworld the local environment might be too dilute to allow abiogenesis. On the other hand abiogenesis might happen elsewhere in the system and life could be transferred to this planet and thrive. Or the local microbiota might not resemble Earth species at all.

Other possibilities; a living ocean, full of specialised forms that cooperate together to form a superorganism; or a mechanical ecosystem, formed from organic self-replicating probes sent there millions or biollions of years ago. There are many others.

you are correct on the radius. i thought I read it was 2.4 x mass of earth but I was mistaken.

I assume high gravity - 3-10 gee wouldnt affect bacteria, but it would animal and plant life for sure. If it were only 3-4 Gee then I could see it having similar but smaller flora and fauna. Of course it would likely be nothing like earth life in form factor. but, who knows?

it would be great to analyze it for an atmosphere!!

eburacum45
2011-Dec-06, 06:38 PM
Why? The encephalisation could be the same, given the alien is 1/3 the height of a human. The pressure difference from head to toe is the same. The required support material scales properly. But the head would be either one third the height of a human head, or three times as heavy.

IsaacKuo
2011-Dec-06, 07:45 PM
But the head would be either one third the height of a human head, or three times as heavy.
For the example I give, it would be one third the height of a human head. I said this hypothetical alien would have proportions similar to us, but would be 1/3 the scale.

Encephalisation is the mass ratio of brain matter to total body mass, so an alien with similar proportions to us would have the same encephalisation.

Basically, I was just taking the easiest approach toward an example of a hypothetical 3gee alien similar to a human.

Have you ever read about the scaling laws that make "giant ants" impossible? Well, those scaling laws work in reverse also. The same laws which make a scaled up ant impossible also make a scaled down human possible for a high gravity world.

But still, there are limits. One third scale is fine, because there are plenty of primates that size. But if we start talking 10 gees or more, we're starting to stretch things.

eburacum45
2011-Dec-06, 08:40 PM
Encephalisation is the mass ratio of brain matter to total body mass, so an alien with similar proportions to us would have the same encephalisation.
Yes, it is. But would a human with a brain with 1/3 the volume of an earthly human brain be equally sapient? The lateral compression would reduce its function, I think. The encephalisation quotient rule probably doesn't work when comparing the brains of creatures from different gravity regimes.

IsaacKuo
2011-Dec-06, 08:49 PM
Yes, it is. But would a human with a brain with 1/3 the volume of an earthly human brain be equally sapient?
My guess is that it wouldn't, but I wasn't aiming for an example which was fully human in characteristics. I was aiming low, to merely provide a plausible counterexample to you claim that the planet "certainly does not hold anything resembling a human."

To me, a small primate 1/3 of human height does resemble a human. An alien with a humanoid body and proportions, would also qualify as resembling a human.

eburacum45
2011-Dec-06, 09:28 PM
Hmm; so we might get some short, relatively dumb humanoid bipeds, but probably not fully sapient humanoids.

I'm more inclined to a belief that a sapient lifeform on a high gravity world would be some sort of centaur, perhaps using manipulatory organs developed from mandibles. Or a cone-like being with muscles that anchor to the peak of the cone for strength. The high gravity would favour small animals, for many reasons; they are stronger with respect to their size, and have faster reactions to deal with the speed of falling objects. Only in water could a creature grow to any great size.

eburacum45
2011-Dec-06, 09:35 PM
Another problem with high-grav worlds is the probable persistence of hydrogen in the atmosphere. Any oxygen produced by photosynthesis would combine and form water. Not really a problem if anaerobic metabolism systems can support complex organisms; this recent discovery suggests that may be possible.
http://en.wikipedia.org/wiki/Loricifera#In_anoxic_environment

IsaacKuo
2011-Dec-07, 08:15 AM
Hmm; so we might get some short, relatively dumb humanoid bipeds, but probably not fully sapient humanoids.

I wouldn't go that far. I'm just saying that my specific example of a hypothetical alien with human proportions at 1/3 scale might plausibly be only on the level of small primates. A more stocky build may result in something more like a fantasy dwarf, with a large head and brain.


I'm more inclined to a belief that a sapient lifeform on a high gravity world would be some sort of centaur, perhaps using manipulatory organs developed from mandibles. Or a cone-like being with muscles that anchor to the peak of the cone for strength. The high gravity would favour small animals, for many reasons; they are stronger with respect to their size, and have faster reactions to deal with the speed of falling objects. Only in water could a creature grow to any great size.

Maybe, but 3x gravity isn't all that extreme.

Still, extreme gravity could have interesting implications on flight and projectile weaponry. Flight and gliding are out of the question, but simple falling is a potent weapon. Sloth-like beings hanging from tree limbs or cliff sides could target victims below using rocks or shells or darts. Hanging lets the creature rely on tension for support, eliminating the balance problems of bipeds and upright quadrupeds.

IsaacKuo
2011-Dec-07, 08:36 AM
Another problem with high-grav worlds is the probable persistence of hydrogen in the atmosphere. Any oxygen produced by photosynthesis would combine and form water. Not really a problem if anaerobic metabolism systems can support complex organisms; this recent discovery suggests that may be possible.
http://en.wikipedia.org/wiki/Loricifera#In_anoxic_environment

In the past, I have expressed skepticism that aerobic metabolism is necessary for complex life, and used the above as an example. However, I was told by a biologist that the energy available from anaerobic metabolism still puts a limit on the size of practical life forms. Still, I remained skeptical...but I am starting to change my mind because of the history of oxygen levels on Earth.

It started when a discussion of exoplanet habitability brought to my attention the fact that Earth itself wasn't human habitable for most of its history due to insufficient oxygen levels. For billions of years, oxygen levels were limited by geological absorption. So what happened once that was saturated? Boom! Oxygen levels rise, and complex life explodes.

That said, hydrogen gas is a highly reactive energetic molecule. I suspect that a hydrogen atmosphere could serve the same basic role as an oxygen atmosphere for "aerobic" equivalent life. Just with the roles of oxidizer and fuel reversed. This couldn't have happened here on Earth, because Earth wasn't big enough to hold onto its hydrogen gas. But maybe it could happen on a super-earth or mini-neptune.

eburacum45
2011-Dec-07, 10:34 AM
A more stocky build may result in something more like a fantasy dwarf, with a large head and brain.
Something like this, perhaps; Kobold (http://www.orionsarm.com/xcms.php?r=oaeg-view-article&egart_uid=47fc240a5e94f) (yes, its one of mine). I have no problem anticipating that humans may one day be modified to thrive in high gravity; but I think a high gravity superearth would probably be such a different environment to Earth that humanoids would be unlikely to evolve there.

iquestor
2011-Dec-07, 01:44 PM
IsaacKuo said
It started when a discussion of exoplanet habitability brought to my attention the fact that Earth itself wasn't human habitable for most of its history due to insufficient oxygen levels. For billions of years, oxygen levels were limited by geological absorption. So what happened once that was saturated? Boom! Oxygen levels rise, and complex life explodes.

In Rare Earth (Brownlee, Ward) the authors make the case that Oxygen is required for complex animals due to the energy requirement and (I seem to recall) development of skeletal structures, etc. We just don't have any other examples of complex animals which developed in anarobic conditions. Of course, that just might be LAWKI and there are ways we havent dreamed of....

Extrasolar
2011-Dec-07, 04:29 PM
Maybe biological density is proportional to the gravity well in which it evolves in. Gullivers Travels goes to space!

thoth II
2011-Dec-07, 06:53 PM
I'm excited by this , so IF the star is about sun size, I would calculate the ratio of K-22b's effective temperature to the earth's by the formula:

(T(K22b) / T(earth) = cube root (365 days/290 days) = 1.08, or about 273 Kelvin ( 0 celsius), which comports closely to NASA 's estimate of 22 celsius.

So the effective temp. of this planet would only be 8% higher than earth. Of course, this has nothing to do with surface temperature which is largely dependent on the density and composition of the planetary atmosphere, compare and constrast the sister planets earth-Venus.

PraedSt
2011-Dec-07, 08:47 PM
I'm excited by this , so IF the star is about sun size, I would calculate the ratio of K-22b's effective temperature to the earth's by the formula:

(T(K22b) / T(earth) = cube root (365 days/290 days) = 1.08, or about 273 Kelvin ( 0 celsius), which comports closely to NASA 's estimate of 22 celsius. If you don't mind, where did you get that relationship for effective temperature? A cube root seems too much considering incoming radiation inversely varies with distance squared.

thoth II
2011-Dec-07, 09:04 PM
oh, I did that kind of fast,

what I did was keep the solar output of K-22b's star equal to sun's for this estimate. Then I first from Kepler's 3rd law estimate the ratio of earth's distance from star to K-22b's by raising the period ratio (365/290 days) to the 2/3 powers. That give the distance of earth from star as 1.17 as K-22b's from its star, that part would be easy. Then use the usual formula for effective temperature using Stefan's law where the energy output of the planet is proportional to the fourth power of the temperature. If earth is 1.17 times as far as K-22b is, then by inverse square law it would get 1/(1.17)(squared) = .73 as much solar irradiance per square meter as does K-22b. So the effective temp. of earth should be the one-fourth power of 0.73 = 0.92 as high as K-22b's. Thus K-22b's effective temp. would be 1/0.92 = 1.08 , which we can get easier by algebra as cube root of the period in days ratio.

But the effective temp. of earth can easily be determined , I think even wikipedia shows that and it is 255 Kelvin. So I would quickly estimate K-22b's effective temp as 1.08 X 255 = 275 Kelvin.

The average temp. of the earth's surface at bottom of troposphere is a whole other matter, because of course that involves variables such as atmosphere. NASA got a estimate of 295 Kelvin for K-22b so my rough calc. is in the ballpark.

PraedSt
2011-Dec-07, 09:17 PM
That's great, thanks. I actually forgot the radiation bit. So you're assuming an equilibrium temp, and therefore equating incoming with outgoing. Got it.

JCoyote
2011-Dec-08, 07:03 AM
The problem is that our assumptions are based on our own planet specifically around essentially one system of biochemistry. Different ratios of materials in the environment lead to different chemistry solutions. Would alien life forms use a calcium based support structure? With different chemistry on hand maybe they wouldn't. Is the structure we are familiar with the strongest possible that could be grown by an organism? Depending on the availability of different chemicals, I have doubts that it is.

And evolutionary drive... perhaps there hasn't been evolutionary pressure to develop a skeletal system that much stronger than we have seen so far. If animals don't die because of skeletal breakage before bearing young a significant percentage of the time, there isn't pressure to possess a stronger skeleton. Perhaps there have been stronger skeleton developments, but maybe they came with disadvantages in our environment but would be worth the trade offs in another. There is a flawed assumption of evolutionary "progress" that creates the impression that evolutionary outcomes are overall ideal and thus across the board "best". Nonlethal mediocrity is a valid situation though.

I wouldn't expect to see something like a T-Rex on a high gravity world. But if I have no basis for comparison from all of THAT planet's factors, I can't honestly be surprised either.

Paul Wally
2011-Dec-08, 11:19 AM
If this planet is more massive than Earth then the surface air pressure should also be higher. Doesn't that increase the boiling point of water? If "habitable zone" is defined as a liquid water zone then the zone should depend on the mass of the planet also. I would say the more massive the planet is the further away from the sun will its habitable zone be.

ComeBreakMe
2011-Dec-08, 07:30 PM
I saw this release a few days ago. I'm not that excited about Kepler-22b. It's 600 light years away. Until we figure out a way to fold space-time, we aren't going to be traveling there to confirm whether or not if this planet can support life. I was much more intrigued by the discovery of planets in the Gliese 581 system that could possibly contain life. Gliese 581 is only 20 light years away. There's a chance of us actually being able to view this system in our lifetimes.

Githyanki
2011-Dec-09, 12:07 AM
I'm sure, 20,000 years from now our descendants will colonize it without the thought it was the first exo-planet to be Earth-like; even the thought, "Earth-like" will have no meaning for them as they will probably have been born from a place not of Earth nor would they have any knowledge of Earth.

iquestor
2011-Dec-09, 02:11 AM
I saw this release a few days ago. I'm not that excited about Kepler-22b. It's 600 light years away. Until we figure out a way to fold space-time, we aren't going to be traveling there to confirm whether or not if this planet can support life. I was much more intrigued by the discovery of planets in the Gliese 581 system that could possibly contain life. Gliese 581 is only 20 light years away. There's a chance of us actually being able to view this system in our lifetimes.

We can at least analyze the atmosphere (if it exists) of 22b and if there is life its very possible we can tell from this analysis.
as far as G581 -- 20 light years is as bad as 600. There is no way we will go or send a probe to 581 (or even Alpha C) in the next 50-75 years unless we are the recipient of alien technology, or we make a giant breakthrough in warp drives. I'd be very surprised if humans themselves make it past mars in the next 50, or 100 for that matter. which is sad to me.

Extrasolar
2011-Dec-09, 04:40 PM
If this planet is more massive than Earth then the surface air pressure should also be higher. Doesn't that increase the boiling point of water? If "habitable zone" is defined as a liquid water zone then the zone should depend on the mass of the planet also. I would say the more massive the planet is the further away from the sun will its habitable zone be.

Excellent point. Not to mention the effect of radioactive decay within the planet or other internal mechanisms. Crust thickness, planet density. Someone needs to come up with the equation that can predict the totality of all the possible effects. The theory of habitability (lol).


I saw this release a few days ago. I'm not that excited about Kepler-22b. It's 600 light years away. Until we figure out a way to fold space-time, we aren't going to be traveling there to confirm whether or not if this planet can support life. I was much more intrigued by the discovery of planets in the Gliese 581 system that could possibly contain life. Gliese 581 is only 20 light years away. There's a chance of us actually being able to view this system in our lifetimes.

I agree, but this is (I think) making news because of the type of star rather than the type of planet. There are much closer planet candidates that reside in their stars 'habitable zone'.

publiusr
2011-Dec-10, 08:11 PM
The fact that the planet is more massive than Earth could mean that it holds one or two moons.

That's what I'm hoping, that this object is actually two objects--an Earthlike Moon orbiting a larger SuperEarth...

whimsyfree
2011-Dec-11, 02:40 AM
That's what I'm hoping, that this object is actually two objects--an Earthlike Moon orbiting a larger SuperEarth...

There are numerous gas giants in stars' HZ which would be more suitable objects for that brand of wishful thinking.


Excellent point. Not to mention the effect of radioactive decay within the planet or other internal mechanisms. Crust thickness, planet density. Someone needs to come up with the equation that can predict the totality of all the possible effects. The theory of habitability (lol).


Numerous papers have been published on the topic. I don't see how it can be a rocky planet (by which I mean a planet which is at least 99.9% rocks and metal by mass) with a mass less than 10.

RetepO
2012-Feb-04, 09:02 PM
I've just registered with BAUT and I regret to see this thread fade away. The posts are all fascinating and contributed by people who have evidently studied the topic of planets and life, but most seem to be tackling a very broad subject one parameter at a time. Does anyone know of any work in the literature that tries to deal with the subject of life on habitable planets that are more massive than Earth?

Githyanki
2012-Feb-05, 01:50 AM
Another thought, it just how old is the star? In about 2 billion years, Earth will have an atmosphere similar to Venus's; with our instruments, we'd think Earth was Earth-like then.

willstaruss22
2012-Jun-23, 10:31 AM
bigger earth bigger gravity much thicker atmosphere i would say not habitable.

swampyankee
2012-Jun-23, 06:50 PM
Speculation is fun.

We need somebody with some formal experience in biomechanics to step in. I don't, so I'll consider my speculation ill-informed.

> I think tetrapods are an evolutionary accident. Given the sample size, who knows?

> Larger land-based lifeforms are more affected by gravity, especially by falling, than are small ones. Drop a mouse down a well, it walks away. For the same drop, a cat is stunned, a man is killed, and a horse splashes (iirc, this is from JBS Haldane).

> I don't think that extraterrestrial biologies will permit things like bones that are orders of magnitude stronger than terrestrial equivalents (actually, both bone and wood are quite good structural materials -- Geoffrey Dehavilland's use of wood, vs aluminum, in the Mosquito did not require miracles of design).

So, do I think that intelligent aliens are possible under 10 times Earth gravity? Sure. First, they could evolve in a marine environment, where gravity is not a structural constraint. Second, I don't see a particular need for an intelligent creature to be largely vertical, as are humans. Pressure is not going to be a constraint as long as it permits complex chemistry. I know Earth biochemistry works at about 1100 bar, because stuff lives at the bottom of Challenger Deep, so my WAG is that some form of biochemistry would be possible at ten times that pressure.

Gravity is a constraint, but not a preventive. Pressure isn't even a major constraint.

whimsyfree
2012-Jun-24, 01:45 AM
Pressure is not going to be a constraint as long as it permits complex chemistry. I know Earth biochemistry works at about 1100 bar, because stuff lives at the bottom of Challenger Deep, so my WAG is that some form of biochemistry would be possible at ten times that pressure.


WAG? I thought that stood for "wives and girlfriends". At 10 times that pressure water would be in the form of one of the dense high pressure ices. I don't know if biochemistry can take place in such a medium, but it seems to me you could just as well propose life on Jupiter or Uranus. They have the elemental ingredients for life and zones with Earth-like temperatures too.


Gravity is a constraint, but not a preventive.

How to you propose to test your hypothesis that there is intelligent life on this planet?

swampyankee
2012-Jun-25, 12:08 AM
WAG? I thought that stood for "wives and girlfriends". At 10 times that pressure water would be in the form of one of the dense high pressure ices. I don't know if biochemistry can take place in such a medium, but it seems to me you could just as well propose life on Jupiter or Uranus. They have the elemental ingredients for life and zones with Earth-like temperatures too.



How to you propose to test your hypothesis that there is intelligent life on this planet?

I didn't hypothesize that there was life; I speculated that there is no particular reason there couldn't be. Terrestrial biochemistry does work to 1100 bar, although there are changes in the behavior of some reactions relevant to biology. As for the other issue? Do note, too, that liquid water can exist at 11000 bar; it just needs to be warmer than about 320 K -- see the phase diagram (http://www.lsbu.ac.uk/water/phase.html#intr2).

whimsyfree
2012-Jun-25, 03:27 AM
I didn't hypothesize that there was life; I speculated that there is no particular reason there couldn't be.


That doesn't seem scientifically interesting to me. Life that we can detect (or can detect us) is interesting to me; whimsy about life we will never meet, not so. I can't be certain, but I doubt the first contact will be with creatures that live in the depths of a panthalassic super-Earth. It's just such a bad base for space exploration and communication.


Do note, too, that liquid water can exist at 11000 bar; it just needs to be warmer than about 320 K -- see the phase diagram (http://www.lsbu.ac.uk/water/phase.html#intr2).

Thanks for that.

ZunarJ5
2012-Jul-21, 03:42 AM
Speculation is fun.

We need somebody with some formal experience in biomechanics to step in. I don't, so I'll consider my speculation ill-informed.

> I think tetrapods are an evolutionary accident. Given the sample size, who knows?

> Larger land-based lifeforms are more affected by gravity, especially by falling, than are small ones. Drop a mouse down a well, it walks away. For the same drop, a cat is stunned, a man is killed, and a horse splashes (iirc, this is from JBS Haldane).

> I don't think that extraterrestrial biologies will permit things like bones that are orders of magnitude stronger than terrestrial equivalents (actually, both bone and wood are quite good structural materials -- Geoffrey Dehavilland's use of wood, vs aluminum, in the Mosquito did not require miracles of design).

So, do I think that intelligent aliens are possible under 10 times Earth gravity? Sure. First, they could evolve in a marine environment, where gravity is not a structural constraint. Second, I don't see a particular need for an intelligent creature to be largely vertical, as are humans. Pressure is not going to be a constraint as long as it permits complex chemistry. I know Earth biochemistry works at about 1100 bar, because stuff lives at the bottom of Challenger Deep, so my WAG is that some form of biochemistry would be possible at ten times that pressure.

Gravity is a constraint, but not a preventive. Pressure isn't even a major constraint.

Perhaps something else to add to your list; the chambered manner in which plants transfer fluid from roots to branches could be a useful circulatory adaptation to high gravity animal life.

Noclevername
2012-Jul-21, 04:30 AM
Life that we can detect (or can detect us) is interesting to me; whimsy about life we will never meet, not so.

If by "we" you mean those of us alive today, probably not. But don't rule out the possibility of some future generation of humanity or post-humanity doing so. We have a long future ahead of us, assuming we don't kill ourselves off.

In either case, instead of "whimsy" you could call it rather, a thought-experiment.

CARREEN
2012-Sep-04, 05:28 PM
The fact that the planet is more massive than Earth could mean that it holds one or two moons.

Two Moons, means always Moonlight ? If always moonlight probably there have no Sun.

eburacum45
2012-Sep-05, 05:39 AM
Two Moons, means always Moonlight ? If always moonlight probably there have no Sun.

Moonlight is reflected sunlight; if there is no sunlight, there is no moonlight.