8 ms·

A Moon of Saturn Has a Sea, Scientists Say

178 points by sheri 12y ago

jmpe 12y ago
"Dr. Tsou devised a way to capture comet particles and bring them back to Earth for NASA’s Stardust mission and has been suggesting a similar method for a spacecraft that would fly through Enceladus’ plumes and then return to Earth for scientists to examine. The challenges are to make sure that the interesting particles would not break apart, to take precautions that any alien life would not infect Earth, and to fit it into the $500 million budget of one of NASA’s lower-cost planetary missions." Why bring it back to earth? Wouldn't it be safer & less expensive to return it to ISS instead, (or is that what's implied) ? Didn't know the carbon & nitrogen part of the story, read the article thinking only 1 thing: "when are you going to mention Europa".
- maaku 12y ago
  > Why bring it back to earth? Wouldn't it be safer & less expensive to return it to ISS instead, (or is that what's implied) ? No, that would involve a very complicated and expensive breaking maneuver to slow down the spacecraft, not to mention getting in exactly the right orbit to rendezvous with the ISS. It's much, much easier to just the payload sturdy enough to survive atmospheric entry and a crash landing.
  - mkingston 12y ago
    Expensive breaking is precisely what they're trying to avoid! (Sorry, normally I wouldn't nitpick spelling when the meaning is clear, it was just a funny error!)
    - maaku 12y ago
      Hah! I had to reread twice to spot the mistake. That's too awesome; I'm going to leave it as-is.
  - rkuykendall-com 12y ago
    What about crashing it into the moon? Higher cost, but much less chance of earth contamination. We could then check it out with cheap robots.
    - didgeoridoo 12y ago
      An object coming in from a rendezvous with Saturn would be traveling at a ludicrous speed. You would probably vaporize on lunar impact. The Earth's atmosphere can help slow it down to a reasonable velocity--otherwise you have to carry a lot more fuel to burn in a slow-down maneuver.
      - hrjet 12y ago
        Similar to how a swing-by is used to accelerate a space-vehicle, I wonder if a swing-by could be used to decelerate as well.
        vilhelm_s 12y ago
        According to Wikipedia, the MESSENGER mission to Mercury used a complicated series of fly-bys of Earth, Venus and Mercury to slow down.
        Tuna-Fish 12y ago
        It can. The boost is proportional to the cos(final exit trajectory in relation to the planet, velocity of planet) -- so if the probe leaves the planet opposite to the direction it goes around the sun, it slows down. (that is, the probe as whole can still orbit the sun in the same direction as the planet, it just needs to do it slower.
      - BrandonMarc 12y ago
        Ludicrous speed?! I bet they have hyperjets on that thing! (ducks)
  - fit2rule 12y ago
    Send two missions, one with the capture device, the other with a functioning remote-controlled robot laboratory. Leave them close to the region, set them up to explore for 50 years or so. I know, I know, budgets. It'll 'never' happen. But what if we just send a nano-factory with its own assembly/disassembly abilities? Feasible, 5 - 10 years on from now? Well anyway, the point is: why bring it back, really? Just send more machines to do better jobs in space.
- TrainedMonkey 12y ago
  I doubt in orbit rendezvous with ISS would be safer and cheaper. It might be safer from planetary contamination standpoint, but complexity of such maneuver would handily offset that. On top of that there is a host of other issues due to the cramped space on ISS. For example: not enough space for proper isolation of sample, not enough equipment to properly study sample, and the fact that limited manpower would be available for examination. Regarding planetary contamination, with the amount of meteorites hitting ocean I do not think we have anything to worry about.
  - jmpe 12y ago
    That makes sense. But regarding your last sentence: I'm not very fond of that risk analysis. Potentially introducing an alien aquatic micro-organism (that's what we hope to bring back, remember) into earth's system... No competition, paradise compared to its hostile home. No meteorite has ever been shown to carry life, but into this case we intend to deliberately introduce it, either controlled or uncontrolled. NASA can bill me for the extra cost for taking it to ISS instead of earth's surface.
    - bausson 12y ago
      No competition? A life form which evolved in a (relatively) low-energy environment (low temperature, low light level, lower pressure) is more in hell than in a paradise. Earth organism evolved to make the best of available resources on Earth, be it energy or materials; the organism would be teared apart in no-time. That is, unless it is a highly intelligent and evolved life form with big environment alteration capacities, but then it might already be a problem, just one we aren't aware of.
  - civilian 12y ago
    Eh, I've played KSP, an orbital rendezvous in LEO on your return isn't that hard. If you have enough precision and fuel leftover to start a safe decent, you have enough precision and fuel to dock with the ISS. I'm surprised that we aren't equally worried about contaminating Enceladus with terran microbes.
- elnate 12y ago
  In regards to the contamination, I don't think that would be a real risk. Earth life has spent billions of years both adapting and adapting to the environment to make it the best growing medium and even then it exists in exclusive bands. For example, put a polar bear in the desert or a fresh water fish in salt water. It is more likely that we would have to take extreme care not to kill any lifeforms we brought back than to worry about them killing us.
  - jmpe 12y ago
    You're seriously underestimating this issue. - rabbits/cane toads in Australia [0][1] - Japanese knotweed [2] - Tumbleweed (yep, not as native as Hollywood suggests) [3] - Algae [4] ... and the list goes on and on, here's a top-100: http://en.wikipedia.org/wiki/List_of_the_world%27s_100_worst_invasive_species http://en.wikipedia.org/wiki/List_of_the_world%27s_100_worst... [0] http://www.youtube.com/watch?v=pgPhn4tYxJQ http://www.youtube.com/watch?v=pgPhn4tYxJQ [1] http://en.wikipedia.org/wiki/Cane_toads_in_Australia http://en.wikipedia.org/wiki/Cane_toads_in_Australia [2] http://www.environment-agency.gov.uk/homeandleisure/wildlife/130079.aspx http://www.environment-agency.gov.uk/homeandleisure/wildlife... [3] http://en.wikipedia.org/wiki/Kali_tragus http://en.wikipedia.org/wiki/Kali_tragus [4] http://plants.ifas.ufl.edu/node/89 http://plants.ifas.ufl.edu/node/89
  - TeMPOraL 12y ago
    I don't think anyone is worried about space bears or space fish; but bacteria / viruses / other basic replicator forms have much bigger resistance to harsh environments.
TempleOSV2 12y ago
C:\TAD\Text\Words\AUGUST.TXT It is one thing then for a man to think that to be ill which is good, as the forenamed do; another, that that which is good, a man should see that it is good (as Thy creatures be pleasing unto many, because they be good, whom yet Thou pleasest not in them, when they prefer to enjoy them, to Thee); and another, that when a man sees a thing that it is good, God should in him see that it is good, so, namely, that He should be loved in that which He made, Who cannot be loved, but by the Holy Ghost whic
Mz 12y ago
This is amusingly relevant to my life: Dr. McKay, who was not involved with gravity measurements, noted that only Enceladus was known to possess the four essential ingredients for life, at least as it exists on Earth: liquid water, energy, carbon and nitrogen. “I would say it’s our best bet,” he said. Mars has a dearth of nitrogen, found in amino acids and proteins, and the surface today is dry and cold. Europa, which also possesses an under-ice ocean, may have all of the ingredients, but that has not been confirmed. Amusingly, I have Europa as a colony in a comic I write. In mentioning this elsewhere just now, a physicist has suggested this resource to me: http://en.wikipedia.org/wiki/Solar_System_in_fiction#Comics_and_animation http://en.wikipedia.org/wiki/Solar_System_in_fiction#Comics_... I shall have to learn yet more about our solar system so I can make up dumb bs for humor's sake. (Not that I expect anyone here to really care. I am just cracking up over this.)
deleted 12y ago
[deleted]
- deleted 12y ago
  [deleted]
twic 12y ago
"All these worlds are yours, except Europa. Attempt no landings there. Oh, and stay off Enceladus too." Doesn't quite have the same ring to it.
- deleted 12y ago
  [deleted]
hellbanner 12y ago
"They found that the moon’s gravity was weaker at the south pole. At first glance, that is not so surprising; there is a depression at the pole, and lower mass means less gravity. But the depression is so large that the gravity should actually have been weaker." They found the gravity was weaker.. but it should actually have been weaker. So is it weaker or stronger?
- cnaut 12y ago
  it should have been weaker than it was
- wiredfool 12y ago
  I think that they mean that they gravity should have been even weaker than it was. * There's a depression -> gravity weaker. * Less of a difference than expected from the depression size -> something denser * Water is denser than ice, and in a known relation -> size/volume of lake.
  - mturmon 12y ago
    A bit more on this, from the abstract at http://www.sciencemag.org/content/344/6179/78 http://www.sciencemag.org/content/344/6179/78: "We determined the quadrupole gravity field of Enceladus and its hemispherical asymmetry using Doppler data from three spacecraft flybys. Our results indicate the presence of a negative mass anomaly in the south-polar region, largely compensated by a positive subsurface anomaly compatible with the presence of a regional subsurface sea at depths of 30 to 40 kilometers and extending up to south latitudes of about 50°. And a little more on methodology, from the full article: "The design of the Cassini spacecraft does not allow radio tracking from Earth during remote-sensing observations. Therefore, only 3 of the 19 flybys of Enceladus completed so far have been used for gravity measurements. In these close encounters, the spacecraft was continuously tracked from ground antennas while flying within 100 km of the moon’s surface, twice above the southern hemisphere (in the flybys labeled E9 and E19) and once over the northern hemisphere (E12). We determined Enceladus’ quadrupole gravity field and degree-3 zonal harmonic coefficient J3 from measurements of spacecraft range-rate. And further detail on the effects modeled: "Microwave links between the onboard transponder and ground stations of NASA’s Deep Space Network enabled precise measurements of the spacecraft range-rate. In addition to gravitational forces, our analysis accounts for the main nongravitational accelerations, most notably neutral particle drag exerted by the substantial gas plume formed by the jets of the south-polar region. Flying by the moon at latitudes below –70°, the spacecraft interacts with the plume at distances of up to 500 km from Enceladus’ surface..." Amazing results. They're flying ~100 km from the moon's surface, while at a distance of 1.3 billion km. And getting very accurate velocities due to the mighty Doppler effect.
api_or_ipa 12y ago
why did you not just say Enceladus? Surely HN doesn't need reductionist titles.
- gus_massa 12y ago
  It’s against the current guidelines that say that you should use the exact title, but I don’t like this part of the guidelines. (But there are some horror stories of heavy editorialized titles.) On the other hand I didn’t know Enceladus until today. (I fist thought the story was about Titan.) My preferred title for the HN submission would be “Enceladus, A Moon of Saturn, Has a Sea” or “A Moon of Saturn [Enceladus] Has a Sea”.
api_or_ipa 12y ago
why did you not just say Enceladus? Surely HN doesn't need reductionist titles.
api_or_ipa 12y ago
why did you not just say Enceladus? Surely HN doesn't need reductionist titles.
danieltillett 12y ago
If there is an sea on Enceladus then there will already be microbial life there [0]. Microbes can survive for ages in space [1] and there are plenty of rocks moving from the earth and all of the other planets and moons of the solar system [0,2]. One of the more interesting stories about microbes in space is that some survived on the moon for almost three years inside a camera [3]. It is not 100% certain that the microbes cultured were not from later contamination, but I know from working with them that microbes are really tough and I can believe that they could have survived! [0] http://users.tpg.com.au/horsts/transpermia.html http://users.tpg.com.au/horsts/transpermia.html [1] http://www.ncbi.nlm.nih.gov/pubmed/19854226 http://www.ncbi.nlm.nih.gov/pubmed/19854226 [2] http://en.wikipedia.org/wiki/Panspermia http://en.wikipedia.org/wiki/Panspermia [3] http://en.wikipedia.org/wiki/Reports_of_Streptococcus_mitis_on_the_Moon http://en.wikipedia.org/wiki/Reports_of_Streptococcus_mitis_...
- anigbrowl 12y ago
  Transpermia seems like a theory rather than a fact. While I think you're probably correct, it's better to be ultra-conservative on questions like this.
  - danieltillett 12y ago
    Of course it is only a theory, but a very plausible one given the frequency of rock transfer between planets and the toughness of microbes that allow them to survive in space for long time periods (both empirical facts). There is really no way of proving transpermia - even if we to travel to Enceladus and found microbial life there how would we ever prove how it got there.
    - conkrete 12y ago
      If we find DNA based microbial life it could certainly be amazing evidence in favor of transpermia. We would at least compare to DNA on earth and analyze similarities. Even plant and animal DNA are very similar (double helix shape)
kimonos 12y ago
Interesting! Thanks for sharing!
deleted 12y ago
[deleted]
hownottowrite 12y ago
Cool shot of the ice jets from 2005: http://apod.nasa.gov/apod/ap091124.html http://apod.nasa.gov/apod/ap091124.html Plus NASA's actual release about the sea: http://science.nasa.gov/science-news/science-at-nasa/2014/03apr_deepocean/ http://science.nasa.gov/science-news/science-at-nasa/2014/03...
netcan 12y ago
The last paragraph is good writing. The challenges are to make sure that the interesting particles would not break apart, to take precautions that any alien life would not infect Earth, and to fit it into the $500 million budget of one of NASA’s lower-cost planetary missions. It frames it all beautifully. Engineering feats solving problems you don't quite understand. Sci fi potential. Budgetary drudgery.

178 points by sheri 12y ago

jmpe 12y ago

"Dr. Tsou devised a way to capture comet particles and bring them back to Earth for NASA’s Stardust mission and has been suggesting a similar method for a spacecraft that would fly through Enceladus’ plumes and then return to Earth for scientists to examine. The challenges are to make sure that the interesting particles would not break apart, to take precautions that any alien life would not infect Earth, and to fit it into the $500 million budget of one of NASA’s lower-cost planetary missions." Why bring it back to earth? Wouldn't it be safer & less expensive to return it to ISS instead, (or is that what's implied) ? Didn't know the carbon & nitrogen part of the story, read the article thinking only 1 thing: "when are you going to mention Europa".

maaku 12y ago
> Why bring it back to earth? Wouldn't it be safer & less expensive to return it to ISS instead, (or is that what's implied) ? No, that would involve a very complicated and expensive breaking maneuver to slow down the spacecraft, not to mention getting in exactly the right orbit to rendezvous with the ISS. It's much, much easier to just the payload sturdy enough to survive atmospheric entry and a crash landing.
- mkingston 12y ago
  Expensive breaking is precisely what they're trying to avoid! (Sorry, normally I wouldn't nitpick spelling when the meaning is clear, it was just a funny error!)
  - maaku 12y ago
    Hah! I had to reread twice to spot the mistake. That's too awesome; I'm going to leave it as-is.
- rkuykendall-com 12y ago
  What about crashing it into the moon? Higher cost, but much less chance of earth contamination. We could then check it out with cheap robots.
  - didgeoridoo 12y ago
    An object coming in from a rendezvous with Saturn would be traveling at a ludicrous speed. You would probably vaporize on lunar impact. The Earth's atmosphere can help slow it down to a reasonable velocity--otherwise you have to carry a lot more fuel to burn in a slow-down maneuver.
    - hrjet 12y ago
      Similar to how a swing-by is used to accelerate a space-vehicle, I wonder if a swing-by could be used to decelerate as well.
      - vilhelm_s 12y ago
        According to Wikipedia, the MESSENGER mission to Mercury used a complicated series of fly-bys of Earth, Venus and Mercury to slow down.
      - Tuna-Fish 12y ago
        It can. The boost is proportional to the cos(final exit trajectory in relation to the planet, velocity of planet) -- so if the probe leaves the planet opposite to the direction it goes around the sun, it slows down. (that is, the probe as whole can still orbit the sun in the same direction as the planet, it just needs to do it slower.
    - BrandonMarc 12y ago
      Ludicrous speed?! I bet they have hyperjets on that thing! (ducks)
- fit2rule 12y ago
  Send two missions, one with the capture device, the other with a functioning remote-controlled robot laboratory. Leave them close to the region, set them up to explore for 50 years or so. I know, I know, budgets. It'll 'never' happen. But what if we just send a nano-factory with its own assembly/disassembly abilities? Feasible, 5 - 10 years on from now? Well anyway, the point is: why bring it back, really? Just send more machines to do better jobs in space.
TrainedMonkey 12y ago
I doubt in orbit rendezvous with ISS would be safer and cheaper. It might be safer from planetary contamination standpoint, but complexity of such maneuver would handily offset that. On top of that there is a host of other issues due to the cramped space on ISS. For example: not enough space for proper isolation of sample, not enough equipment to properly study sample, and the fact that limited manpower would be available for examination. Regarding planetary contamination, with the amount of meteorites hitting ocean I do not think we have anything to worry about.
- jmpe 12y ago
  That makes sense. But regarding your last sentence: I'm not very fond of that risk analysis. Potentially introducing an alien aquatic micro-organism (that's what we hope to bring back, remember) into earth's system... No competition, paradise compared to its hostile home. No meteorite has ever been shown to carry life, but into this case we intend to deliberately introduce it, either controlled or uncontrolled. NASA can bill me for the extra cost for taking it to ISS instead of earth's surface.
  - bausson 12y ago
    No competition? A life form which evolved in a (relatively) low-energy environment (low temperature, low light level, lower pressure) is more in hell than in a paradise. Earth organism evolved to make the best of available resources on Earth, be it energy or materials; the organism would be teared apart in no-time. That is, unless it is a highly intelligent and evolved life form with big environment alteration capacities, but then it might already be a problem, just one we aren't aware of.
- civilian 12y ago
  Eh, I've played KSP, an orbital rendezvous in LEO on your return isn't that hard. If you have enough precision and fuel leftover to start a safe decent, you have enough precision and fuel to dock with the ISS. I'm surprised that we aren't equally worried about contaminating Enceladus with terran microbes.
elnate 12y ago
In regards to the contamination, I don't think that would be a real risk. Earth life has spent billions of years both adapting and adapting to the environment to make it the best growing medium and even then it exists in exclusive bands. For example, put a polar bear in the desert or a fresh water fish in salt water. It is more likely that we would have to take extreme care not to kill any lifeforms we brought back than to worry about them killing us.
- jmpe 12y ago
  You're seriously underestimating this issue. - rabbits/cane toads in Australia [0][1] - Japanese knotweed [2] - Tumbleweed (yep, not as native as Hollywood suggests) [3] - Algae [4] ... and the list goes on and on, here's a top-100: http://en.wikipedia.org/wiki/List_of_the_world%27s_100_worst_invasive_species http://en.wikipedia.org/wiki/List_of_the_world%27s_100_worst... [0] http://www.youtube.com/watch?v=pgPhn4tYxJQ http://www.youtube.com/watch?v=pgPhn4tYxJQ [1] http://en.wikipedia.org/wiki/Cane_toads_in_Australia http://en.wikipedia.org/wiki/Cane_toads_in_Australia [2] http://www.environment-agency.gov.uk/homeandleisure/wildlife/130079.aspx http://www.environment-agency.gov.uk/homeandleisure/wildlife... [3] http://en.wikipedia.org/wiki/Kali_tragus http://en.wikipedia.org/wiki/Kali_tragus [4] http://plants.ifas.ufl.edu/node/89 http://plants.ifas.ufl.edu/node/89
- TeMPOraL 12y ago
  I don't think anyone is worried about space bears or space fish; but bacteria / viruses / other basic replicator forms have much bigger resistance to harsh environments.

TempleOSV2 12y ago

C:\TAD\Text\Words\AUGUST.TXT It is one thing then for a man to think that to be ill which is good, as the forenamed do; another, that that which is good, a man should see that it is good (as Thy creatures be pleasing unto many, because they be good, whom yet Thou pleasest not in them, when they prefer to enjoy them, to Thee); and another, that when a man sees a thing that it is good, God should in him see that it is good, so, namely, that He should be loved in that which He made, Who cannot be loved, but by the Holy Ghost whic

Mz 12y ago

This is amusingly relevant to my life: Dr. McKay, who was not involved with gravity measurements, noted that only Enceladus was known to possess the four essential ingredients for life, at least as it exists on Earth: liquid water, energy, carbon and nitrogen. “I would say it’s our best bet,” he said. Mars has a dearth of nitrogen, found in amino acids and proteins, and the surface today is dry and cold. Europa, which also possesses an under-ice ocean, may have all of the ingredients, but that has not been confirmed. Amusingly, I have Europa as a colony in a comic I write. In mentioning this elsewhere just now, a physicist has suggested this resource to me: http://en.wikipedia.org/wiki/Solar_System_in_fiction#Comics_and_animation http://en.wikipedia.org/wiki/Solar_System_in_fiction#Comics_... I shall have to learn yet more about our solar system so I can make up dumb bs for humor's sake. (Not that I expect anyone here to really care. I am just cracking up over this.)

deleted 12y ago

[deleted]

deleted 12y ago
[deleted]

twic 12y ago

"All these worlds are yours, except Europa. Attempt no landings there. Oh, and stay off Enceladus too." Doesn't quite have the same ring to it.

deleted 12y ago
[deleted]

hellbanner 12y ago

"They found that the moon’s gravity was weaker at the south pole. At first glance, that is not so surprising; there is a depression at the pole, and lower mass means less gravity. But the depression is so large that the gravity should actually have been weaker." They found the gravity was weaker.. but it should actually have been weaker. So is it weaker or stronger?

cnaut 12y ago
it should have been weaker than it was
wiredfool 12y ago
I think that they mean that they gravity should have been even weaker than it was. * There's a depression -> gravity weaker. * Less of a difference than expected from the depression size -> something denser * Water is denser than ice, and in a known relation -> size/volume of lake.
- mturmon 12y ago
  A bit more on this, from the abstract at http://www.sciencemag.org/content/344/6179/78 http://www.sciencemag.org/content/344/6179/78: "We determined the quadrupole gravity field of Enceladus and its hemispherical asymmetry using Doppler data from three spacecraft flybys. Our results indicate the presence of a negative mass anomaly in the south-polar region, largely compensated by a positive subsurface anomaly compatible with the presence of a regional subsurface sea at depths of 30 to 40 kilometers and extending up to south latitudes of about 50°. And a little more on methodology, from the full article: "The design of the Cassini spacecraft does not allow radio tracking from Earth during remote-sensing observations. Therefore, only 3 of the 19 flybys of Enceladus completed so far have been used for gravity measurements. In these close encounters, the spacecraft was continuously tracked from ground antennas while flying within 100 km of the moon’s surface, twice above the southern hemisphere (in the flybys labeled E9 and E19) and once over the northern hemisphere (E12). We determined Enceladus’ quadrupole gravity field and degree-3 zonal harmonic coefficient J3 from measurements of spacecraft range-rate. And further detail on the effects modeled: "Microwave links between the onboard transponder and ground stations of NASA’s Deep Space Network enabled precise measurements of the spacecraft range-rate. In addition to gravitational forces, our analysis accounts for the main nongravitational accelerations, most notably neutral particle drag exerted by the substantial gas plume formed by the jets of the south-polar region. Flying by the moon at latitudes below –70°, the spacecraft interacts with the plume at distances of up to 500 km from Enceladus’ surface..." Amazing results. They're flying ~100 km from the moon's surface, while at a distance of 1.3 billion km. And getting very accurate velocities due to the mighty Doppler effect.

api_or_ipa 12y ago

why did you not just say Enceladus? Surely HN doesn't need reductionist titles.

gus_massa 12y ago
It’s against the current guidelines that say that you should use the exact title, but I don’t like this part of the guidelines. (But there are some horror stories of heavy editorialized titles.) On the other hand I didn’t know Enceladus until today. (I fist thought the story was about Titan.) My preferred title for the HN submission would be “Enceladus, A Moon of Saturn, Has a Sea” or “A Moon of Saturn [Enceladus] Has a Sea”.

api_or_ipa 12y ago

why did you not just say Enceladus? Surely HN doesn't need reductionist titles.

api_or_ipa 12y ago

why did you not just say Enceladus? Surely HN doesn't need reductionist titles.

danieltillett 12y ago

If there is an sea on Enceladus then there will already be microbial life there [0]. Microbes can survive for ages in space [1] and there are plenty of rocks moving from the earth and all of the other planets and moons of the solar system [0,2]. One of the more interesting stories about microbes in space is that some survived on the moon for almost three years inside a camera [3]. It is not 100% certain that the microbes cultured were not from later contamination, but I know from working with them that microbes are really tough and I can believe that they could have survived! [0] http://users.tpg.com.au/horsts/transpermia.html http://users.tpg.com.au/horsts/transpermia.html [1] http://www.ncbi.nlm.nih.gov/pubmed/19854226 http://www.ncbi.nlm.nih.gov/pubmed/19854226 [2] http://en.wikipedia.org/wiki/Panspermia http://en.wikipedia.org/wiki/Panspermia [3] http://en.wikipedia.org/wiki/Reports_of_Streptococcus_mitis_on_the_Moon http://en.wikipedia.org/wiki/Reports_of_Streptococcus_mitis_...

anigbrowl 12y ago
Transpermia seems like a theory rather than a fact. While I think you're probably correct, it's better to be ultra-conservative on questions like this.
- danieltillett 12y ago
  Of course it is only a theory, but a very plausible one given the frequency of rock transfer between planets and the toughness of microbes that allow them to survive in space for long time periods (both empirical facts). There is really no way of proving transpermia - even if we to travel to Enceladus and found microbial life there how would we ever prove how it got there.
  - conkrete 12y ago
    If we find DNA based microbial life it could certainly be amazing evidence in favor of transpermia. We would at least compare to DNA on earth and analyze similarities. Even plant and animal DNA are very similar (double helix shape)

kimonos 12y ago

Interesting! Thanks for sharing!

deleted 12y ago

[deleted]

hownottowrite 12y ago

Cool shot of the ice jets from 2005: http://apod.nasa.gov/apod/ap091124.html http://apod.nasa.gov/apod/ap091124.html Plus NASA's actual release about the sea: http://science.nasa.gov/science-news/science-at-nasa/2014/03apr_deepocean/ http://science.nasa.gov/science-news/science-at-nasa/2014/03...

netcan 12y ago

The last paragraph is good writing. The challenges are to make sure that the interesting particles would not break apart, to take precautions that any alien life would not infect Earth, and to fit it into the $500 million budget of one of NASA’s lower-cost planetary missions. It frames it all beautifully. Engineering feats solving problems you don't quite understand. Sci fi potential. Budgetary drudgery.