Water Vapor Detected Above Europa

by Paul Gilster on December 16, 2013

Last week’s look at Europa examined the possibility of primordial impacts there that might have brought organic materials to the moon, focusing especially on clay-like minerals that a JPL team found in data from the Galileo mission. I had barely finished that article before the news from Hubble arrived with observations of water vapor above the southern pole of Europa, a possible indication of water plumes erupting from the moon’s surface. That work ran in Science Express and was reported at the meeting of the American Geophysical Union in San Francisco. Lead author Lorenz Roth (Southwest Research Institute) described it this way:

“By far the simplest explanation for this water vapor is that it erupted from plumes on the surface of Europa. If those plumes are connected with the subsurface water ocean we are confident exists under Europa’s crust, then this means that future investigations can directly investigate the chemical makeup of Europa’s potentially habitable environment without drilling through layers of ice. And that is tremendously exciting.”

Exactly so, for now we can start thinking about doing something similar to what has been envisioned at Enceladus, flying a spacecraft through a plume to study what’s below the ice. As the comments on last Thursday’s post (Europa: Minerals from an Ancient Impact) have shown, the question of ice thickness on Europa is wide open, and scientists studying the matter are divided on it — once again I point you to Richard Greenberg’s Unmasking Europa (Copernicus, 2008) for a lively defense of thin ice.

europa_vents_2

Image: This graphic shows the location of water vapor detected over Europa’s south pole that provides the first strong evidence of water plumes erupting off Europa’s surface, in observations taken by NASA’s Hubble Space Telescope in December 2012. Hubble didn’t photograph plumes, but spectroscopically detected auroral emissions from oxygen and hydrogen. The aurora is powered by Jupiter’s magnetic field. This is only the second moon in the solar system found ejecting water vapor from the frigid surface. The image of Europa is derived from a global surface map generated from combined NASA Voyager and Galileo space probe observations. Credit: NASA, ESA, and L. Roth (Southwest Research Institute and University of Cologne, Germany).

Geysers on Europa could indeed be a signature of a thin ice crust, but as reader Andrew Tribick has noted here, they could also flag a lake enclosed within a thick crust. The key question, of course, is just where the water is coming from. “Do the vents extend down to a subsurface ocean or are the ejecta simply from warmed ice caused by friction stresses near the surface?” Roth asks. So far we don’t know. And as to the source of the faint emissions detected by Hubble, the long cracks on Europa’s surface known as lineae may well be the answer. That would correspond to the fissures that the Cassini spacecraft has seen near the south pole of Enceladus.

But whatever the thickness of Europa’s ice, flying through a plume rather than drilling would make our task immeasurably easier. We can also take up Freeman Dyson’s suggestion, noted in the comments by Larry Klaes, that space around Europa should be investigated for the possible remains of aquatic life forms that could have been blown out by impact events.

Another reminder of Enceladus is the fact that the intensity of the plumes detected on Europa varies with the moon’s orbital position. The jets are detected only when Europa is at the farthest point in its orbit from Jupiter, while signs of venting disappear when the moon is closer. Are we looking at tidal flexing caused by Jupiter’s gravitational pull? That’s what one would expect with a subsurface ocean placed in this environment. It’s interesting that Europa’s own gravity, twelve times that of Enceladus, would cause any water vapor to fall back to the surface, leaving surface features near the south pole that may be observable by future spacecraft.

The paper is Roth et al., “Transient Water Vapor at Europa’s South Pole,” published online in Science 12 December 2013 (abstract).

tzf_img_post

{ 49 comments… read them below or add one }

ljk December 16, 2013 at 12:09

Here is an article by Freeman Dyson about Europan life:

http://www.theatlantic.com/past/issues/97nov/space.htm

To quote:

“Every time a major impact occurs on Europa, a vast quantity of water is splashed from the ocean into the space around Jupiter. Some of the water evaporates, and some condenses into snow. Creatures living in the water far enough from the impact have a chance of being splashed intact into space and quickly freeze-dried.

“Therefore, an easy way to look for evidence of life in Europa’s ocean is to look for freeze-dried fish in the ring of space debris orbiting Jupiter. Sending a spacecraft to visit and survey Jupiter’s ring would be far less expensive than sending a submarine to visit and survey Europa’s ocean. Even if we did not find freeze-dried fish in Jupiter’s ring, we might find other surprises — freeze-dried seaweed, or a freeze-dried sea monster.

“Freeze-dried fish orbiting Jupiter is a fanciful notion, but nature in the biological realm has a tendency to be fanciful. Nature is usually more imaginative than we are. ”

Dyson’s TED talk on the subject:

http://tedxproject.wordpress.com/2010/05/23/freeman-dyson-lets-look-for-life-in-the-outer-solar-system/

Dyson even suggested looking for flowers on the surface of the icy alien moon:

http://www.newscientist.com/article/dn17078-could-flowers-bloom-on-icy-moon-europa.html#.Uq8kwvRDtPI

Much of this is an exercise in thinking outside the box when it comes to alien life in alien environments, which is always a good thing. We used to think there was all kinds of life on Mars until we actually got there. We certainly know Europa better than we did Mars before Mariner 9 went into orbit around the Red Planet in 1971.

In a similar vein, we used to think Venus was covered in either swampy jungles or oceans of various kinds of liquid. When we discovered the entire surface was over 900 degrees F., life on that planet was rejected almost outright. However, some have said there could be hardy microbes in the more pleasant layers of that planet’s thick atmosphere, or buried under its surface where temperatures and other conditions are not so bad. Even Io has been considered a possible place for life due to its dynamic nature.

Harry R Ray December 16, 2013 at 14:17

This is an answer to MY OWN QUESTION in a comment to the EARLIER post (comment # 17, if you are interested):Europa:Minerals from an ancient impact. It would be USELESS to have the JUNO spacecraft fly through the plumes, BUT, due to magnetic abnormalities Galeleo detected as the spacecraft passed near Europa with a clear close-up view of the south polar region,, if , after its primary missio n is concluded,before its scheduled entry into the jovian atmosphere, (or:IF THE MISSION CAN BE EXTENDED), follow-up MAGNETIC readings may be possible to VERIFY the Galeleo results.

Michael December 16, 2013 at 14:26

There are highly energised particles in Jupiter’s magnetosphere making the life span of organics rather limited. However on the surface of Europa there will be grooves and gullies that will not be affected by the radiation as much as they will be acting as a shield as the radiation will be glancing the moons surface with respect to them.

I found this article about radiation on Europa

http://people.virginia.edu/~rej/papers09/Paranicas4003.pdf

As for the water vapour it could be produced by landslides caused by tidal stresses due to Europa’s orbital path.

Gregory Benford December 16, 2013 at 14:56

LJK is right to point out Dyson’s trademark out-of-the-box thinking on Europa. I’ve looked into his ideas on finding plants on iceteroids, and indeed a serious effort could see them now. I also portrayed them in a story drawn from Freeman’s remarks to me, see
http://www.tor.com/stories/2013/04/backscatter
The man is a national asset!
Gregory Benford

FrankH December 16, 2013 at 15:56

We should be spending more research money on Europa, rather than on Mars. If there was ever life on Mars, it’s long dead and gone.

If the search for extra-terrestrial life is important, Europa at least has either a sub-surface ocean or a slushy, watery mantle.

Even though Europa is much harder to reach and the immediate environment is much harsher than Mars, it’s worth the effort.

The technical issues are daunting, but by far the greatest hurdles are institutional inertia (NASA can’t refocus it’s Mars program in a decade or less), internal politics and funding.

Wojciech J December 16, 2013 at 17:10

To be fair it is a rather safe bet that life it it existed on Mars, could be found underneath the surface or in polar ice caps.
In previous topics we discussed about likelihood of life being transported by ejecta from Earth to other celestial objects, and there are studies showing that Jupiter’s moons got a fair share of chance of being hit with rocks with microbes in them.
So life on Europa wouldn’t surprise me at all.

steven rappolee December 16, 2013 at 17:15

I am thinking that duo to gravitational flexing that maybe Europa’s crust is thick at the equator then the poles?

Tulse December 16, 2013 at 17:43

Is there any reason to think that Europa is a better candidate for life than Enceladus? It seems like Enceladus is a much more benign environment for an orbiter, and it seems to have more regular plumes expelling water (and whatever it may contain) into space.

James M. Essig December 16, 2013 at 18:59

ljk,

I like the robotic Saturnian ring study idea.

I’d still like to send a probe such as an ice-melter to check out any sub-surface oceans though.

I love to find some ET sea monsters or even jelly fish. It is plausible that some sub-surface life-forms might have intelligence similar to dolphins and whales in Earth’s oceans.

BTW, great thread Paul. It will be interesting to see what we can find over the next few decades on Europa/

ljk December 17, 2013 at 9:47

James M. Essig said on December 16, 2013 at 18:59:

“ljk, I like the robotic Saturnian ring study idea.”

In the 1990s I had an idea to drop probes equivalent to cubesats into the rings of Saturn to gently move around sampling and imaging the surfaces of ring chunks as they bounced off and among them. The probes I envisioned would look something like soccer balls.

http://www.mail-archive.com/europa@klx.com/msg02992.html

ljk December 17, 2013 at 9:52

Icy Europa May Have First Evidence For Active Plate Tectonics on an Alien World

BY BETSY MASON

12.16.13 12:54 PM

SAN FRANCISCO — Scientists may have spotted the first evidence for active plate tectonics on another world. Jupiter’s moon Europa is covered in an ice crust bearing scars that may reveal movement similar to that of Earth’s rocky plates.

Europa was already considered to be among the most scientifically intriguing bodies in the solar system and one of the most promising places to hunt for life in the solar system because of the liquid ocean that resides beneath its crust. If the latest findings turn out to be true, it could be another point in favor of the moon’s potential habitability by providing a way to get nutrients from the surface down into the ocean.

“What’s exciting is that this would be the only other place outside of Earth where a plate-tectonic-style system is occurring,” said planetary scientist Alyssa Rhoden, a NASA postdoctoral program fellow who studies Europa, but was not involved in the new research.

Europa’s icy surface has been estimated to be between 40 million and 90 million years old, making it one of the youngest surfaces in the solar system, and far younger than the moon itself, which is more than 4 billion years old. This means that somehow the crust is being refreshed either by resurfacing or recycling of old crust.

Scientists believe new ice is being formed on Europa along linear features called dilational bands. There are thousands of kilometers of these bands on the planet, potentially creating significant amounts of new ice crust. The problem is that nobody knows where all the old crust is disappearing.

“Unless Europa has been expanding within the last 40 to 90 million years, there has to be some process on this icy moon that’s able to accommodate a large amount of new surface area being created at dilational bands,” planetary scientist Simon Kattenhorn of the University of Idaho said during a presentation about the new research Dec. 13 at the American Geophysical Union meeting.

Full article here:

http://www.wired.com/wiredscience/2013/12/plate-tectonics-on-europa/

To quote:

“I think we are going to be hard pressed to make any global map of tectonics with our current data set,” Rhoden told WIRED. This is a good argument for a new mission to Europa, which could also help us understand Earth better, she says. There is still a lot of disagreement among scientists about what drives plate tectonics on Earth, and even if the driving force on Europa is different, it could be enlightening.

James M. Essig December 17, 2013 at 13:15

Interesting link, ljk.

The soccer ball shape adds to the coolness factor. The cool think is that with carbonaceous super-materials, good sturdy colliders are within reach.

Not sure how durable carbon nanotubes, grapheme, grapheme-oxide paper, boron nitride nanotubes and the like would hold up in the cold of Saturnian ring environments, however, such materials might be great if they are cold tolerant.

Michael December 17, 2013 at 14:10

Surely if plate tectonic processes are taking place there should be more red staining. I mean if the red material is coming from the ocean below it should also move across as the ice sheets move across the ocean and are in turn sub-ducted, in effect these sheets should be more red which they are clearly not. Maybe there is just localized upwelling and sub-duction along cracks over a few-to-tens of kilometres driven by density changes due to the temperature of the ocean below and tidal forces opening and closing cracks which should keep the ice slushy. This may be a means to more precisely define the thickness of the ice crust and a possible entry point for nuclear powered -driller/subs- if they are ever used.

torque_xtr December 17, 2013 at 15:38

If Ganymede and Callisto cratering rates apply to Europa too, there almost certainly were chicxulub+ class impacts in it’s history, which would penetrate as deep as the ocean floor and eject some of it’s material to the surface, where it would freeze into floor material-contaminated layer. So there may be areas with some floor and deep ocean material mixed into near-surface materials. These may be scattered everywhere now, given the dynamics, but with the right choice of landing place it might be possible to investigate them in-situ only with some roving and only a shallow drilling. If all the floor material-contaminated ice has been recycled, this is bad for looking for floor material, but good for ocean investigation, since faster recycling rates mean that more of the surface was recently the water of the ocean.

And, which is much more exciting to the short-term, the plume material could be collected by some of those ion drive-equipped cube-sats and returned here, like it was proposed for Enceladus!

(bet at least some ejecta-transported descendants of terrestrial life would be found there eventually… This is a great place to study panspermy and abiogenesis, and the relative importance of them…)

ljk December 17, 2013 at 16:26

The geysers would mean that the Europa Ice Clipper concept proposed in 1997 would no longer require the Deep Impact style heavy copper ball to retrieve samples of the moon for return to Earth:

http://archive.is/BdqH

http://www.sciencedirect.com/science/article/pii/S0273117702004805

Here is a mission plan for sampling the plume material from Enceladus for return to Earth that could work for Europa as well:

http://futureplanets.blogspot.com/2013/12/discovery-missions-for-icy-moon-with.html

ljk December 17, 2013 at 16:34

What CubeSats could do at Europa, quoted from this article:

http://futureplanets.blogspot.com/2013/10/cubesats-to-planets-ive-seen-evolution.html

“Many possibilities exist for CubeSats sent to locations too dangerous for a multi-hundred million dollar spacecraft. One possibility would be for a Europa flyby mother craft to deploy CubeSats to crash onto the surface of Europa. As the CubeSats make their plunge, they would gather high resolution images of potential future landing sites or areas of scientific interest that they would relay back to the mother craft.”

ljk December 17, 2013 at 18:44

Support the Europa Clipper Mission:

http://europa.seti.org/

Mundus Gubernavi December 17, 2013 at 20:03

I agree, torque_xtr. I always held a suspicion of the Galileo space probe having a part in seeding the areas around Jupiter. Although it was sent into Jupiter’s atmosphere to avoid forward contamination, to me it doesn’t seem like after 8 years in the system and probably having loads of microbes on board it would make a difference at that point. Plus, [not entirely sure, but...] isn’t Jupiter’s atmosphere itself filled with enough water to maybe support some form of life? Life is highly unlikely to survive in the volatile, highly pressurized environment, but I wouldn’t ‘x’ out the virility of Earth’s microbial travelers.

There’s also the risk of seeding possibly more virile life than that from Earth if the theories of someone like Chris McKay [ http://www.youtube.com/watch?v=bbkTJeHoOKY hold true and there are lifeforms surviving on liquid methane on Titan. The danger then would lie in using the moon as not only a refueling post, but an alien transportation network to aid in the spread of such life across whatever destinations the methane powered spacecrafts would venture?

Michael December 18, 2013 at 4:06

@Mundus Gubernavi

‘I agree, torque_xtr. I always held a suspicion of the Galileo space probe having a part in seeding the areas around Jupiter.’

The radiation zones around Jupiter are very high, I doubt cells will survive that amount of damage and still be viable and then they would have to survive the km/s impact with the surface in a frozen state.

ljk December 18, 2013 at 10:38

Here are some Russian plans from 2009 for Europan landers and penetrators:

http://futureplanets.blogspot.com/2009/04/europa-hard-landers-and-penetrators.html

Alex Tolley December 18, 2013 at 12:54

I wouldn’t rule out bacterial survival in Jupiter space, as some bacteria are very radiation resistant.

D. radiodurans is capable of withstanding an acute dose of 5,000 Gy (500,000 rad) of ionizing radiation with almost no loss of viability, and an acute dose of 15,000 Gy with 37% viability.[10][11][12] A dose of 5,000 Gy is estimated to introduce several hundred double-strand breaks (DSBs) into the organism’s DNA (~0.005 DSB/Gy/Mbp (haploid genome)). For comparison, a chest X-ray or Apollo mission involves about 1 mGy, 5 Gy can kill a human, 200-800 Gy will kill E. coli, and over 4,000 Gy will kill the radiation-resistant tardigrade.

Several bacteria of comparable radioresistance are now known, including some species of the genus Chroococcidiopsis (phylum cyanobacteria) and some species of Rubrobacter (phylum actinobacteria); among the archaea, the species Thermococcus gammatolerans shows comparable radioresistance.[5] Deinococcus radiodurans also has a unique ability to repair damaged DNA. It isolates the damaged segments in a controlled area and repairs it. This bacteria can also repair many small fragments from an entire chromosome.

– Wikipedia

Even some basic shielding might be enough to keep down the radiation levels to tolerable levels for these organisms.

As for the pressures in Jupiter’s atmosphere, the water clouds are at around 5 bar. This is considerably less than the hundreds of bar at the ocean depths and thousands in the lithosphere where bacteria survive in the hot rock.

While I doubt that the Galileo probe caused any contamination, I suspect there is a possibility that bacteria could both survive in the atmosphere of Jupiter and safely hitch a ride there from ejecta.

ljk December 18, 2013 at 15:47

Earth and Mars may have “contaminated” Europa and other places long before humans came along with their germy little space probes:

http://www.americaspace.com/?p=46630

Michael December 18, 2013 at 16:02

Here is an article about the radiation around Europa, not for the faith hearted.

http://www.iki.rssi.ru/conf/2009elw/presentations/presentations_pdf/session2/podzolko_getselev_ELW.pdf

850,000,000 rad in 2 months with no shielding, over 10 million rad per day!

As for the bacteria, tough little blighters

http://www.genomenewsnetwork.org/articles/07_02/deinococcus.shtml

But I think the radiation will win.

torque_xtr December 18, 2013 at 16:26

The considerations for plume material return mission: the radiation dose needed to sterilize the sample is probably much smaller than the dose needed to completely destroy it’s structure and make it unrecoverable for Earth-based investigations. The latter probably is not less than ~1% of energy needed to break every chemical bond in the sample. Even the samples which received ~100000 Grays would still be useful. That means some years in the Europa orbit. That is especially good, because if the microprobe spends some weeks in Europa orbit, samples would be very possibly sterilized but destroyed, and this diminishes biohazard.
PS taking all the recent advance in the panspermy mechanisms theory, it’s not likely the samples would be real hazard (even not sterilized). What if deinococcus radiodurans is a double migrant, it’s ancestors blasted into Europa at the dawn of life in the solar system, adapted there to high-radiation environment and then blasted here again some billions of years later with a 10-km+ impact? (for icy chunks to survive the way into inner system) Sounds not entirely crazy these days…

Alex Tolley December 18, 2013 at 18:46

@Michael – yes the radiation dose at Europa is high, but it is reduced by orders of magnitude with almost minimal shielding. v This means that a probe like Galileo could conceivably harbor bugs like D. radiodurans in a survivable manner. Far more likely that such bugs, encased in chunks of rock could make the journey to Europa successfully.

@torque_xtr

What if deinococcus radiodurans is a double migrant, it’s ancestors blasted into Europa at the dawn of life in the solar system, adapted there to high-radiation environment and then blasted here again some billions of years later (…)

Interesting idea. More likely the bug is not adapted directly to radiation, but to another extreme condition that also allows it to be radiation resistant. It also isn’t impossible that radiation resistance was evolved on Earth, as a sub-critical Uranium reactor did once form naturally in S. Africa(?).

If Europa is sterile, could we engineer bugs and algae with radiation resistance to seed the moon to start “greening” it?

torque_xtr December 19, 2013 at 15:00

>>If Europa is sterile, could we engineer bugs and algae with radiation resistance to seed the moon to start “greening” it?

Probably so, since the conditions are quite similar to Earth’s deep sea, but more likely, if the natural seeding has already occured, the transported life had much time to evolve and is more adapted than the engineered. (but for human-assistant seeding the exceptional hardiness and ability to withstand megayears in space isn’t required, and the diversity of species which could be transported is much bigger – maybe there are species that could thrive in Europa’s oceans but not be transported by lithopanspermy)
On the likelihood of seeding:
The above-mentioned article about material transportation,
http://www.americaspace.com/?p=46630
(http://arxiv.org/ftp/arxiv/papers/1311/1311.2558.pdf)
shows 3*10^-6 percents of ejecta from Earth reaches Europa, which means 2*10^6 kg of Earth’s material or 6 fragments larger than 3m (which they considered viable) during all the solar system history. Another simulation which is mentioned in the article shows that only the Chicxulub impact ejected into space 7*10^11 kg of material, of which 20000 kg fell to Europa – so certainly there are some Earth rocks and the seeding is likely…

Eniac December 20, 2013 at 1:09

Alex Tolley:

Interesting idea. More likely the bug is not adapted directly to radiation, but to another extreme condition that also allows it to be radiation resistant. It also isn’t impossible that radiation resistance was evolved on Earth, as a sub-critical Uranium reactor did once form naturally in S. Africa(?).

I think the accepted theory is that the DNA repair abilities of Deinococcus have evolved to allow it to survive desiccation, a MUCH more common hazard than radiation. Desiccation also manifests as DNA strand breaks. Boring, yes, but, sadly, most likely to be the truth….

Michael December 20, 2013 at 14:56

An issue just as big as radiation is also the extreme cold, on it’s own the cold should not be a big issue after all it could preserve the cell and there are instances on earth where bacteria can become dormant though this process. But when the cell is frozen the DNA repair mechanisms are not operating leaving radiation to degrade the DNA and even the repair components. Together they would form an effective sterilising mechanism greater than the individual components.

Alex Tolley December 21, 2013 at 16:04

@Michael

But when the cell is frozen the DNA repair mechanisms are not operating leaving radiation to degrade the DNA and even the repair components. Together they would form an effective sterilising mechanism greater than the individual components.

True if the cell wasn’t protected from radiation. This may be the condition on a spacecraft, but not at the center of a big piece of ejecta. This protects the cell from radiation, and as the rock cools, the bacterium is put into cold storage.

The other thing to consider is that any radiation hits are stochastic. so it is likely that a population of bacteria will have some that remain viable by chance, even with exposure. This is very different from macro organisms that get radiation induced cell proliferation.

While the emphasis has been the search for liquid water for life bearing conditions, it is also important that there be readily available carbon sources to exploit, otherwise any bacteria surviving a plunge into Europa’s ocean will starve. Which makes me think that we should also be checking for methane in the plumes as an indicator of a suitable carbon source.

Michael December 22, 2013 at 7:40

@Alex Tolley

There is limit to the size of ejected material if ejected from Earth, I would think it would be in the meter ranges due to the extreme forces applied.
Now lets look at what the organism has to endure,

It must survive ejection from Earth undergoing heat, pressure and high G forces in a small rock/boulder. Now it has to travel to Europa in hibernation due to the extreme cold been exposed to cosmic/solar radiation taking millions years. It must then survive an impact at many km/s undergoing again even higher temperatures, pressures and G forces than ejection from earth. Then the organism will most likely be ejected onto the surface of the moon with little protection against the powerful radiation of Jupiter again frozen and sit there for millions of year before thawing out. That is a lot of factors that are against organisms surviving the trauma.

Alex Tolley December 22, 2013 at 15:40

@Michael – I don’t dispute that it is hard, but I think you are being overly pessimistic.

ejecta size. A lot larger than 1 meter even from Earth.

g forces – bacteria, and especially their spores can survive very high g forces.

Impact of radiation – solved by larger ejecta.

Impact into Europa. If the rock punches through a thin ice layer into the ocean, the organisms might be quite protected from sterilization.

The attrition rate can be very high, but only a few need survive to repopulate.

I think it is worthwhile to look for life in Europa, before we declare it sterile. If it isn’t sterile and the prokaryotic life looks remarkably similar to Earth life, i.e. common genesis, then can/should we go ahead and introduce life?

Rob Henry December 22, 2013 at 16:39

I think Alex Tolley gets right to the heart of the potential for contamination here.

Firstly, Eniac, that radiation resistance mechanism of Deinococcus being maintained by evolutionary pressure for desiccation resistance makes perfect sense. It being evolved for that purpose makes no sense at all when passive means of genome resistance are both more appropriate and far simpler.

But it is this frozen v not frozen problem that I take most note of. Endolithic bacteria divert most of their energy to DNA repair and reproduction, and here I will assume Deinococcus does the same. No reduction in viability with an ACUTE does of 5000 Gy is stunning. Now repair is completed in 2-3 hours in that organism, implying that if not frozen and there is a tiny amount of food, it can cope with 50,000 Gy per day. If it survives, it should do so cozying up to the RTG.

Michael’s point on whether it could it go the other way when the fragment it would come in is so small as to provide little shielding (and freeze quickly) is interesting.

Mundus Gubernavi December 22, 2013 at 19:04

@Alex Tolley & Michael

The Galileo observed evidence of clay prints/Phyllosilicates on Europa, giving into the possibility of a source of energy for microbes to utilize if they so needed, maybe suggesting the presence of biominerals if such is the case?
http://www.jpl.nasa.gov/news/news.php?release=2013-362

http://www.nasa.gov/topics/solarsystem/features/europa20130404.html

Also, for the effects of radiation and “Probing the limits of extremophilic life in extraterrestrial environment‐simulated experiments” (http://arxiv.org/ftp/arxiv/papers/1207/1207.2098.pdf) might be of interest to some of you.

Mundus Gubernavi December 22, 2013 at 19:14

@ Alex

I think if we want to introduce life anywhere it doesn’t already exist, we should have complete control over the genetic information of the introduced life forms, for safety measures. I don’t think we should just set a bunch of organisms loose and let nature take its course, so to speak. We should only do so for the benefit of our own existence in the universe… the reason being, most organisms (besides maybe dogs) don’t hold us in high regard and if an unforeseen adaption takes place, we could be in for many unwanted surprises if we decide to join in the newly burgeoning ecosystem …

Michael December 23, 2013 at 4:06

@Alex Tolley who said

‘I don’t dispute that it is hard, but I think you are being overly pessimistic.’

I am been a realist Alex, the probality of everything going right is very small indeed, more likely is the probality of life developing within the moon on it’s own which I believe is highly likely. There is plenty of warmth and water below the ice covering and during Europa’s very early history it would have been a water world with a vapour atmosphere. There is also now plenty of protection from the radiation by the ice as well as plenty of nutrient/organics mixed in the ice covering at all levels as I have mentioned in earlier threads offering island of oppurtunity for micro organisms.
As for the high G forces some micro organisms can survive very high G forces ’400,000 G’s’ and mulitply successfully, but sudden deceleration in a frozen state while harder materials around them move I am not so sure about.
‘http://www.space.com/11478-alien-life-bacteria-hypergravity.html’

‘Impact of radiation – solved by larger ejecta.’

Larger rocks are statistically less likely and there is also the problem of self serilisation by the huge amount of localised ‘kinetic’ energy that will be released on impact by larger rocks. At say 5 km/s there is sufficent energy to raise the temperature of a 3 m diameter impacting body to thousands of degrees celcius.

‘Impact into Europa. If the rock punches through a thin ice layer into the ocean, the organisms might be quite protected from sterilization.’

The probality of the rock hitting a thin part of the ice covering again is small, maybe earier in it’s history it would have been more likely.

‘The attrition rate can be very high, but only a few need survive to repopulate.’

Quite right it just takes one viable reproducing cell and life is off to a flying start

Rob Henry said

‘But it is this frozen v not frozen problem that I take most note of. Endolithic bacteria divert most of their energy to DNA repair and reproduction, and here I will assume Deinococcus does the same. No reduction in viability with an ACUTE does of 5000 Gy is stunning. Now repair is completed in 2-3 hours in that organism, implying that if not frozen and there is a tiny amount of food, it can cope with 50,000 Gy per day. If it survives, it should do so cozying up to the RTG.’

Now what if the organism is frozen for million years with no repair going on? I doubt the cell will be viable even if it is the hardy D. radiodurans which again has a low probilty of been ejected in the first place from the Earth . The combination of intense radiation and DNA repair suppression would be a deadly sterisation process.

ljk December 23, 2013 at 10:42

http://www.planetary.org/blogs/emily-lakdawalla/2013/12191225-book-review-alien-seas.html

Book Review: Alien Seas, and so much more

Posted by Emily Lakdawalla

2013/12/19 02:42 CST

Alien Seas is ostensibly a book about “oceans in space,” but it delivers so much more. The slender volume contains essays by many active planetary scientists who also happen to be excellent writers, each one of them playing a different riff on the idea of oceans in different environments in the solar system.

It seems like a niche topic — after all, where is there actually liquid water in the solar system, except on Earth and inside some icy moons? — but most of the writers interpret the concept of an “ocean” broadly. In so doing, they each deliver an up-to-date yet concise and accessible summary of the state of planetary science for each different kind of world in the solar system.

On top of all of that, the volume is abundantly illustrated with both well-selected photos and lots of artworks by Michael Carroll, who, along with volcanologist Rosaly Lopes, edited the book. And, with a list price of $29.99, it’s cheap. This is an excellent gift book for the space enthusiast in your life, or even for a science-obsessed high school student. This book could be an inspiration to flights of science fiction fantasy — imagine descending into the fluid-hydrogen ocean of a giant planet, where diamonds fall like snow! — or to initiate an interest in the latest developments in real-life planetary science.

Just look at who contributed chapters:

David Grinspoon on “Chasing the Lost Oceans of Venus”
Tim Parker on “Oceans on Mars”
Rosaly Lopes on “Seas of Molten Rock”
Bob Pappalardo on “Jupiter’s Water Worlds”
John Spencer on “Oceans at the Outer Limits”
Jani Radebaugh on “Sand Seas of the Solar System” (ooh..sssibilant)
Karl Mitchell on “Exotic Seas: Liquid Alkanes on Titan’s Surface”
Kevin Baines and Mona Delitsky on “The Seas of Saturn”
Chris McKay on “The Alien Seas of Earth”
Jeffrey Bennett on “Seas of the Milky Way”

and, as if there weren’t enough art elsewhere in the book, Michael Carroll adds “A Gallery of Maritime Planetscapes”

I have so many more books to review — I will try to post a brief roundup tomorrow. But this book tops my gift list, so I wanted to get to it without any further delay!

Alex Tolley December 23, 2013 at 12:42

@Michael

(…) more likely is the probality of life developing within the moon on it’s own which I believe is highly likely.

That should get us to a testable hypothesis to separate the likelihoods of de novo genesis vs panspermia.

If life is easily created, then we might expect life to be fairly ubiquitous with highly divergent characteristics. Conversely, if genesis is rare and panspermia is the mechanism to distribute life, then life should be rare, highly clustered spatially and share many core attributes, e.g. DNA, same triplet codon usage, conserved protein sequences etc.

Even without a visit to Europa, we may get some clues with the next generation of telescopes.

One problem with easy genesis is that if life is not tightly constrained, we may have difficulty recognizing it with robot probes using Earth centric detection methods because of the assumptions about what is to be detected. A Europa probe may suffer this problem, unless there are “obvious” visible life forms.

I still think Mars is a better bet to look for life, even if it is only to be found as biogenic rock formations preserving a record of early Martian life.

Rob Henry December 23, 2013 at 18:32

I would also like to get back to that other issue I raised. I have seen good estimates of the maximum available power to a Europan ecosystem if the high energy surface materials are to be delivered to the interior at the implied resurfacing rates. These place it at about 1W per square kilometre tops (and more likely a tenth that or less). By comparison Titan’s (as implied by reverse hydrogen flow) has to be more than 20W if it exists at all (being on the surface, its main external power source would be expected to be photosynthesis not chemical). That is why I am interested in lakes within the crust with local surface turnover rates at least a couple of orders of magnitude higher than that average. In particular, I would love to be able to place some sort of new cap on it. Could it be as high as, say 100W/sqkm.

Michael December 24, 2013 at 3:49

@Rob Henry

I believe there is significant amounts of energy available from sulphur compounds and the tidal flexing at these ‘cracks’ that litter the surface. These ‘rafts’ of ice must concentrate energy at the ‘crack’ as they move relative to each other caused by Jupiter and its moons. This relative movement causes churning of organic/nutrient and oxygen compounds within them and keeps the ice slushy. Perhaps organisms have evolved to make use of ice crystals moving past each other on flexing to generate electrical energy to power cellular processes similar to the piezoelectric effect.

Alex Tolley December 24, 2013 at 12:33

@Michael

Perhaps organisms have evolved to make use of ice crystals moving past each other on flexing to generate electrical energy to power cellular processes similar to the piezoelectric effect.

Truly life as we don’t know it. Such organisms would die if they left this hypothetical flexing zone. If piezoelectricity was the power generation for these primary producers, how would that compare as an energy source to even to weak sunlight on Europa.

Alex Tolley December 24, 2013 at 13:10

Teaser article in New Scientist about what we may find in Lake Vostock.

There had better be [non-contaminating] bacterial DNA found if there is going to be any support for panspermia from Earth to Europa. If Lake Vostock proves sterile, I believe that would put severe constraint on the hypothesis.

Rob Henry December 24, 2013 at 16:13

@Michael, that piezoelectric effect would be by far the most efficient use of tidal energy that I’ve ever seen invoked for a biosphere, but is it remotely possible that it could occur as naturally as you posit? Or would this be a case where we would have to invoke very complex forms of life build/laying complex structures.

@Alex Tolley, now I have seen complex mechanisms invoked to allow photosynthesis here. It is necessary because life needs at least some shielding from the ionising radiation – but I also think it would be hard to prevent that radiation making such a shield opaque.

Alex Tolley December 24, 2013 at 18:53

@Rob Henry – that is why L. Vostock is such an interesting “experiment”. Like a cave, it is dark, allowing no photosynthesis. It is also completely sealed off from the outside (except presumably from the rocks below). Any organisms in this lake must be recycling elements with some energy input, although I don’t know from where yet, otherwise the ecosystem would succumb to entropy. This looks like a nice model for the Europan ocean/subsurface lakes after the bugs have arrived. If L. Vostock is sterile, that would imply, to me at least, that panspermia won’t work for Europa, unless energy from hypothetical hot smokers, or the surface, could drive the bacterial ecosystem.

ljk December 26, 2013 at 10:32

How do we know for certain that Lake Vostok was untouched by life for ages? How “clean” are the Russian techniques for exploring that body of water?

Yes, exploring Lake Vostok will help us in exploring Europa properly, but anywhere except Europa is a poor substitute for finding out what is on that moon. We can do it if those with the purse strings and authority can get their acts together.

Alex Tolley December 26, 2013 at 22:47

How do we know for certain that Lake Vostok was untouched by life for ages?

The ice above the lake has been cored and the age inferred from the analysis of this core. Since the core is continuous (and matches nearby cores), we can infer that once the ice sheet covered the lake, it did not melt again, but continued to accrete ice layers.

The issue of how well sterilized the drilling was will be determined by the analysis done this year. Sequence analysis of any genomes found should help determine this.

Of course L. Vostock tells us little about life on Europa, but I think it will shed light on the probability of panspermia and Europa. After that, we have to go and explore.

Eniac December 30, 2013 at 21:08

Michael:

I am been a realist Alex, the probality of everything going right is very small indeed, more likely is the probality of life developing within the moon on it’s own which I believe is highly likely.

I think you are right about the vanishing probability of organisms surviving the trip, much less taking root and thriving in an environment they are far from being adapted to.

On the other hand, your belief that de-novo abiogenesis is “highly likely” is not supported by any evidence. On Earth, abiogenesis is inevitable, because it is a necessary condition for our presence as observers. This is not the case on Europa, where it could be so exceedingly improbable that interplanetary transfection is like a walk in the park in comparison.

Unfortunately, then, in my opinion, the reasonable expectation has to be that we will find no life on Europa, indigenous or imported. Nor anywhere else.

That last part notwithstanding: I hope I am wrong, and I believe the search for life must continue, no matter the odds.

Michael December 31, 2013 at 15:45

Eniac said

‘On the other hand, your belief that de-novo abiogenesis is “highly likely” is not supported by any evidence. On Earth, abiogenesis is inevitable, because it is a necessary condition for our presence as observers. This is not the case on Europa, where it could be so exceedingly improbable that interplanetary transfection is like a walk in the park in comparison.

Unfortunately, then, in my opinion, the reasonable expectation has to be that we will find no life on Europa, indigenous or imported. Nor anywhere else.

That last part notwithstanding: I hope I am wrong, and I believe the search for life must continue, no matter the odds.’

On Europa we have water in liquid form, organics, amino acids, oxygen and nutrients from impact materials ‘Island of opportunity’ as well as the materials on the mantle/water interface. Together with heat from the flexed core and electrical currents that give Europa a small magnetic field in a ocean twice as big as the Earths I favour the side of there been primitive life on Europa given all these pro-life factors.

Happy New Year to you all

Mick

ljk March 7, 2014 at 10:21

May we actually, finally have a real mission to search for life on Europa?

http://www.americaspace.com/?p=54664

ljk March 21, 2014 at 17:15

NASA wants to look for signs of life on Europa — but you can’t get there for $15 million

By Joel Achenbach, Published: March 10, 2014

Europa, a moon of Jupiter first spotted by Galileo four centuries ago, has geysers spewing material from what appears to be a subsurface ocean. It’s not inconceivable that there are fish down there in that cold, dark sea.

Scientists have long dreamed of sending a robotic probe to Europa, and they have put such a mission at the top of their wish list. But Europa is a hard target: It’s very close to Jupiter, and a spacecraft and its instruments would need extra shielding to keep them from being fried in Jupiter’s harsh radiation environment.

The initial estimate of the cost of putting a spacecraft into orbit around Europa was a wince-inducing $4.7 billion. Engineers then came up with a cheaper alternative, in which the spacecraft would go into an orbit around Jupiter that would send it past Europa dozens of times. During these flybys it could sample the material ejected by the geysers, looking for signatures of life in the ocean below the moon’s icy crust. That might cost on the order of $2 billion.

But budgets are tight at NASA. Officials have said there won’t be any new “Flagship” missions costing north of $1 billion in the coming years, other than ones previously approved.

Now comes the Obama administration’s 2015 budget request, which includes $15 million for studying a possible Europa mission. That’s a tiny fraction of the $17.5 billion requested for the agency. It’s less than what Congress has already allotted for Europa studies the last couple of years. But supporters of robotic exploration are grateful that, for the first time, the administration is signaling support for a Europa mission.

But will this mission really materialize? This is the dilemma for anyone writing about NASA these days: The agency sometimes starts programs that fail to survive the erosional forces of politics and constricting budgets.

Full article here:

http://www.washingtonpost.com/national/health-science/nasa-wants-to-look-for-signs-of-life-on-europa–but-you-cant-get-there-for-15-million/2014/03/07/dd2ebe18-a47f-11e3-84d4-e59b1709222c_story.html

Leave a Comment