Well, the best way to find out is to go there and, find out.

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Toxicity is relative. Pretty much any poison you can name, as long as it occurs in nature, something thrives on it. Don't forget, for the kind of lifeforms Earth started out with, oxygen is a deadly poison. Somehow they adapted to its relentless accumulation.

Bigger problem is energy flow. All life on Earth's surface and most of the life in the oceans depends on the sunlight. Sea-bottom volcanoes, known as "black smokers" support their own ecosystems, which depend for energy on hydrogen sulfide black smokers put out. If Sun went out and Earth surface froze over, these sea-bottom ecosystems would go on living for as long as Earth mantle was hot enough for plate tectonic -- probably billions of years. The problem is, Earth generates about one-thousandth as much heat as it gets from the Sun. It means that under the best circumstances total biomass of black smoker communities can not be more than 0.001 of the surface biomass. In practice it is much less than that, because geothermal energy comes out in metabolically useful form (hydrogen sulfide) only under rather special conditions. Most of that energy is wasted in earthquakes.

From tidal stressing Europa gets about half as much energy, per square mile of surface, as Earth gets from radioactive decay in its core. Europa may have some radioactive elements too, but they can not more than double that amount. We have no reason to assume that volcanic activity on Europa is any more (or any less) "bio-friendly" than it is on Earth. Hence we can expect about as much life per square mile of Europa sea bottom as we find of "black smoker life" in Earth's oceans -- that is, very little. The top predators are probably the size of guppies, if that.

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Fiction has to be plausible. Reality is under no such constraint.

Freeman Dyson has suggested a spacecraft sent to the Jupiter system that deploys a large net structure following the orbital path of Europa. The reasoning is that over time asteroids have periodically collided with Europa throwing out water, ice chunks and perhaps lifeforms into orbit. The netting would retrieve the frozen remains.

I would add that perhaps other portions of the netting could contain astrogel panels for collecting possible alien microbes. This is all hypothetical and not likely to be initiated unless life was first discovered under the ice.

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"Insignificant molehill sometimes more important than conspicuous mountain." - Charlie Chan

Regarding the life living around the smokers in the depth of the Earth's oceans. Never mentioned in most documetaries about it is that all of it is decended from live that fossil evidence supports the conclusion evolved far earlier and elsewhere on Earth. To be sure the smokers due to their remoteness have not had a lot of study of their fossil surroundings. Not to mention that the evolutionary evidence indicates that the life around the smokers is very recent. Smokers are hot spots under the crust and since the crust is moving over the hotspots the life that lives in the hotspot dies when the crust where they live moves away from the hotspot. Surely some life will, by some circumstance follow the hotspot and some lfe from elsewhere will decend and evolve to adapt to the hotspot. The hotspots on Earth are too transient to support the conclusion that live could have originated there and then evolved to migrate as the crust moved away from it. There is little reason to suspect that a hotspot on Europa would act any different.

While some of the conditions for life appear to exist on Europa there is the real possibility that life there may have originated elsewhere. My personal suspicions are that Europa does not have the antiquity of the Earth and thus could have had any life it may have deposited on it from the debris meteor impacts of Earth spewed out and contamitated it eons ago. For that matter there has been enough time for meteor impacts of Earth to have spread life from Earth all across the galaxy. Or for life on Earth to have originated from anywhere in the galaxy.

But then that would mean that we are related to life elsewhere in the galaxy.

I think nobody claimed life is likely to exist on Europe,
only that it may well be possible.

Don't forget that early Earth would have been toxic for most of today's life forms, too.
Oxygen, on the other hand, was toxic for most of the early life forms.

Toxic or not just depends on where your particular species feels comfortable

That's a bit 'unfair' as a comparison:
we don't know if a sentient planet is possible.
We do know that certain life forms could conceivable survive on Europe (if that ocean exists).

Can I make that my sig line?

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"If you think the LHC will create black holes, you might as well believe Hobbits are at the bottom of your garden."- Dr. Mike Inglis
Rovers forever! - ToSeek
"Carl Sagan sent a message to ET,
Neil Armstrong walked in the Sea of Tranquility
Steve Squyers built Spirit and Opportunity
Dan Haylen upchucked in zero gravity." -Brent Simon, The Space Camp Song

Thank you, but radiation levels are ok even on the surface today

*blush* I would be honoured.

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Ha - well done, I missed that typo

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This is not an idea to be tossed aside lightly - it should be thrown with great force

Buried on page 99 of Titan Explorer report:

Radiation flux on Europa's surface - 30,000 rad/day
Radiation flux 10 cm below surface - 300 rad/day

There are many problems with life deep inside Europa, but radiation is not one of them.

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Fiction has to be plausible. Reality is under no such constraint.

Worth noting that a dose of just 1,000 rad per day, is lethal for humans.

So even immediately under the ice shell, three days exposure will still kill someone.

I still reckon Europa is sterile & lifeless. The ingrediants are there for sure, but the radiation & increasing toxicity, I dunno.

Toxicity from potential ocean bed volcanoes (assuming said ocean actually exists) & toxicity possibly leeching through the surface ice, from material erupted from neighbouring Io's volcanoes & settling on Europa (sulphur from Io's volcanoes has been found covering Amalthea, as well as places on Europa, Ganymede & Callisto).

Really the only way we will know for sure, is to send a pair of landers, one with seismometers & tilt meters & the other a cryobot, to melt through the ice, both carrying cameras similar to the MERs to image the general forms of the landing site, temperature & multispectral readings of the surrounding landscape.

Another mystery is the fact that Europa may have been resurfaced as recently as 30 million years ago (gauging crater density). Does Europa, like Venus resurface itself at regular intervals?

Europa is a most fascinating world, as are the other Galileans particularly Io. All four are so very different.

Andrew Brown.

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"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.

I believe that the source Ilya referenced means that the radiation is 300 RAD/day 10 cm below the top of the ice, not the bottom. So if you're standing on top of the surface, 10 cm below your feet, there is only 300 RAD/day. Considering that the ice is multiple kilometers thick, I would think there is no appreciable outside radiation reaching any ocean below Europa's surface.

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Yes, they laughed at Einstein, but only because of his silly hairstyle; no one was actually laughing at his science.

Europa is continuously resurfacing itself. The tidal forces created by Jupiter cause the ice to flex, and material from underneath wells up to the surface.

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Yes, they laughed at Einstein, but only because of his silly hairstyle; no one was actually laughing at his science.

Not quite. If life that metabolizes very slowly there can be an awful lot of it living of only a little energy. Although life on Europa would presumably not have much energy to live off, that does not mean there could not be a large amount of biomass. On earth there is aparently more biomass, leading a very slow, low energy existance, deep below the surface than above it. If all the bacteria below underground were suddenly brought up to ground level we'd quite possibly be up to our armpits or more in it.

Hi weatherc, I am enjoying this conversation with you very much.

I see what you are saying, but with my immense collection of Europa imagery & data, it seems to me that the resurfacing is not continuous, but appears episodic, like Venus, but rather volcanic basalt, it is slushy ice.

Perhaps Jupiter's flexing does cause limited localised resurfacing, but not globally all of the time.

It is a great shame that Galileo's HGA failed, as the original high resolution global campaign had to be abandoned, but to me enough ground was still covered to show, that some areas are older than others. Also the search for cryogeysers had to be abandoned also.

Certainly, Conamara Chaos IS a very young region, no doubt what so ever about that. The tilted & shifted ice blocks appear to be within more recent frozen ice, almost like pack ice on the Arctic Ocean, trapping icebergs, & that the 'fresh' ice is not cratered.

What this does seem to suggest that does Europa temporarily have a denser atmosphere during the resurfacing events?

I wonder if the surface contaniments erupted from neighbouring Io's volcanoes could also be used to help date Europa's differing terrain?

Below I hope you like these images of the Conamara Chaos region. I have had to compress them, but if you would like copies of the originals, please let me know & I will send them to you.

1). Crop & enlargement of the ice valleys in the highest resolution fram of Europa in Conanamara Chaos. 6 metres per pixel.

2). 13 KM wide area.

3). 120 metre high ice hill in Conamara Chaos.

4). Detail of Split Berg in Conamara Chaos (1).

5). Detail of Split Berg in Conamara Chaos (2).

6). Detail of Split Berg in Conamara Chaos (3).

7), Europa hemispheric view showing surface sulphur contanimation from Io.

8). Ice blisters / Diapirs on Europa.

Andrew Brown.

Attached Images

	BAUT Europa 6 metre reso small ice valleys Conamara Chaos Galileo.jpg (55.4 KB, 4 views)
	BAUT Europa 13 km area (3) Galileo.jpg (64.1 KB, 3 views)
	BAUT Europa 120 metre high ice hill in Conamara Chaos 9 metre re.jpg (44.6 KB, 3 views)
	BAUT Europa fracture in split ice 'berg' 2 Galileo.jpg (23.8 KB, 2 views)
	BAUT Europa fracture in split ice 'berg' Galileo.jpg (27.5 KB, 4 views)
	BAUT Europa split ice 'berg' 3 Galileo.jpg (35.0 KB, 1 views)
	PIA02500 Europa Frozen sulphuric acid from Io Galileo.jpg (54.1 KB, 1 views)
	BAUT Europa showing ice blisters Galileo.jpg (64.3 KB, 2 views)

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"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.

Yes. Ten centimeters of ice reduce radiation flux by the factor of one hundred.

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Fiction has to be plausible. Reality is under no such constraint.

I do not know if it is paradise. But it IS radiation free.

Do you know that oxygen is extremely toxic gas? Toxicity is not serious argument, because everything is toxic or not toxic relative to given organism.

But in discussion I seen serious arguments, for example problems with accessible energy.

To sum up, as someone said: go and find it out!

Interesting. You surely have some sources to back it up?

Unortunately, interstellar panspermia is almost impossible due to radiation, time and distance scale.

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Sanity is overrated.
Butterfly.