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The deep sea vehicle ALVIN has been exploring the depths, and discovering new animals, even new orders and species. See some of these exotic creatures at the following link. I especially like the worm with no mouth or digestive tract. How it makes a living is an interesting study in symbiosis.

http://gizmodo.com/check-out-all-the-alien-species-deap-sea-vehicle-alvin-1599806486


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Amazing that we share the same kind of DNA with them; and we share the same ancestor, way back a few billion years. I think the appropriate word is 'awesome'. I wonder if a DNA of different origin will ever be found. On Mars, maybe.


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Another place to look for life is on Titan, Jupiter's largest moon. It has an atmosphere and seas that might be able to host life. A number of scientists have speculated that it might be another place to look for life.

Bill Gill


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True Bill, although you mean Titan is Saturn's largest moon (Ganymede is Jupiter's largest); but I'll place my bets on the first ET life being found on Europa.

This is a proposed mission to Titan:
http://www.youtube.com/watch?v=elm2CGKKuQk
http://en.wikipedia.org/wiki/Titan_Saturn_System_Mission

but there are proposals for missions to Europa which, it appears, will be given priority:
http://www.youtube.com/watch?v=3C84cYlHzn4
http://en.wikipedia.org/wiki/Europa_Jupiter_System_Mission


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Fascinating creatures.

There is something humbling about realising that there are so many things, not just in the Universe, but also here on Earth that we know nothing about.


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Sure is. We have a vast encyclopedia of racial knowledge, yet any individual can know barely a syllable of it. That's humbling. Then, further, the racial knowledge itself can be barely a syllable of all there is to be known. That's humbling too.


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Originally Posted By: Bill
Another place to look for life is on Titan, Jupiter's largest moon. It has an atmosphere and seas that might be able to host life. A number of scientists have speculated that it might be another place to look for life.

Bill Gill

Bill, you might find this of interest:
Originally Posted By: (Quoted from Space.com)
Saturn Moon Titan's Underground Ocean May Be Super Salty
July 04, 2014

Gravity data collected by NASA’s Cassini spacecraft suggest that Titan’s ocean must have an extremely high density. Salt water has a higher density than fresh water because the presence of salt adds more mass to a given amount of water.

Researchers think the ocean could be as salty as the Dead Sea of Israel and Jordan, with a high concentration of dissolved salts made of sulfur, sodium and potassium. [Amazing Photos: Titan, Saturn’s Largest Moon]

"This is an extremely salty ocean by Earth standards," study lead author Giuseppe Mitri, from the University of Nantes in France, said in a statement. "Knowing this may change the way we view this ocean as a possible abode for present-day life, but conditions might have been very different there in the past."

http://www.space.com/26444-saturn-moon-titan-salty-ocean.html?cmpid=557877
http://www.space.com/23947-tour-the-strange-lakes-of-saturn-s-moon-titan-video.html


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I wonder if life forms on other planets might use different bases in its DNA. Or if it had DNA at all. Silicon polymerizes nicely and could form the basis for self-replicating molecules, perhaps. I hope they are sterilizing everything so we don't go seeding Earth life on these worlds before we can learn anything about them. I wonder where they are going to get the fuel for a hot air balloon in an atmosphere of methane? What if the atmosphere is combustible, and by lighting a hot air balloon we cause the whole atmosphere to go up in smoke? I'm sure someone has that angle covered, but it seems like a stumbling block nonetheless.

Fascinating to speculate on the forms life might take on other worlds.


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Originally Posted By: Amaranth Rose II
I wonder if life forms on other planets might use different bases in its DNA. Or if it had DNA at all. Silicon polymerizes nicely and could form the basis for self-replicating molecules, perhaps.

I think Carl Sagan invented the term 'carbon chauvinism' in regard to this topic. Silicon does seem to be a viable alternative, doesn't it; but I consider the following:

(1) there's about 7 times more carbon than silicon in the universe *** .
(2) numerous carbon compounds have been found in space. While there's curently no evidence to indicate that such compounds in space lead to biogenesis, it does seem that those compounds form wherever it's possible, given enough time.
(3) carbon can form bonds with a greater range of elements than silicon can, giving rise to a greater number and complexity of compounds.

My guess is that on an any suitable planet with the requisite elements, it's much more likely that carbon, rather than silicon, will be the key player.

Still, as they say, 'Life' is full of surprises.

*** http://periodictable.com/Properties/A/UniverseAbundance.html
_____

Originally Posted By: Amaranth Rose II
I hope they are sterilizing everything so we don't go seeding Earth life on these worlds before we can learn anything about them.

This refers to Mars missions:
http://mars.jpl.nasa.gov/msl/mission/technology/insituexploration/planetaryprotection/
_____

Originally Posted By: Amaranth Rose II
I wonder where they are going to get the fuel for a hot air balloon in an atmosphere of methane? What if the atmosphere is combustible, and by lighting a hot air balloon we cause the whole atmosphere to go up in smoke? I'm sure someone has that angle covered, but it seems like a stumbling block nonetheless.

Is Titan's atmosphere really that combustible? After all, it appears to have survived meteor showers and impacts. Maybe the nitrogen content is too high. However that may be, it looks like they have it figured:
"On Mars, Montgolfieres [balloons] would be heated by the sun...On Titan, Montgolfieres would be heated from a radioisotope power source (RPS)".

http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/38.360/1/05-1506.pdf

Originally Posted By: Amaranth Rose II

Fascinating to speculate on the forms life might take on other worlds.

It sure is, especially in this age, when the search for extraterrestrial life is intensifying.


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They seem to be taking some precautions against contaminating Mars.

"The Mars Science Laboratory Rover will comply with requirements to carry a total of no more than 300,000 bacterial spores on any surface from which the spores could get into the martian environment."

I don't see any reference to spores per unit area. If they are using the value of 300k bacterial spores per square inch, that is a relatively dirty surface. Granted, human skin contains on the order of millions of colony forming units per square inch, so 300,000 might be a reasonable goal, but I would question whether this is per square inch or square centimeter, or on a general surface which might be many square units of surface area.

I just hope we don't seed Mars with terrestrial life and then "discover" it and come to the wrong conclusions. Or kill what life is there by contaminating it. I hope we send a clean spacecraft up.


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They go through some rather extensive attempts to decontaminate the Mars explorers, but there is no way to completely clean all life forms off of them. I believe they blast them with high intensity UV as the last step, but that still doesn't take care of all of them. In the end they just have to do the best they can and then hope for the best.

If life is found on Mars they will be very careful to check to make sure that it isn't contamination from Earth.

Bill Gill


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Rose and Bill

From http://en.wikipedia.org/wiki/Planetary_protection
Originally Posted By: Wiki
Planetary protection>
COSPAR recommendations and categories

* Category IVa. Landers that do not search for Martian life - uses the Viking lander pre-sterilization requirements, 300,000 spores per spacecraft and 300 spores per square meter.
* Category IVb. Landers that search for Martian life. Adds stringent extra requirements to prevent contamination of samples.
* Category IVc. Any component that accesses a Martian Special Region (see below) must be sterilized to at least to the Viking post-sterilization biological burden levels (30 spores total per spacecraft).

Originally Posted By: Wiki
Planetary protection>
Mars Special Regions

A Special Region is a region classified by COSPAR within which terrestrial organisms could readily propagate, or one thought to have an elevated potential for existence of Martian life forms. This is understood to apply to any region on Mars where liquid water occurs, or can occasionally occur, based on the current understanding of requirements for life.

If a hard landing risks biological contamination of a Special Region, then the whole lander system must be sterilized to COSPAR category IVc.

What do you make of that? I imagine a maximum of 30 spores on the entire spacecraft is as near to perfect decontamination as it can get.


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Originally Posted By: redewenur
What do you make of that? I imagine a maximum of 30 spores on the entire spacecraft is as near to perfect decontamination as it can get.

It sounds to me as if it is impossible. I don't think they can possibly get a whole spacecraft that clean.

Bill Gill


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It does seem incredible, doesn't it. I'd like to know more about it, but I haven't yet found details elsewhere.


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However, it says here:

http://www.postandcourier.com/article/20140706/PC1002/140709622

"Mars Curiosity launched with 22 microbial spores per square meter - well within NASA's specifications"


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"Nonetheless, nothing - especially a large space probe - can be sterilized completely. Thus, Mars Curiosity launched with 22 microbial spores per square meter - well within NASA's specifications."

That's pretty good. But I still think we are going to contaminate the surface with some of those stowaways. There are extremophiles of all sorts that could survive the trip. They might not pose a threat to us, but could be deadly to any life on Mars. If there is any, of course. I doubt we will find a booming civilization, but the sands of Mars will not yield up their secrets without a fight. I think it is well worth the effort to attempt to sterilize the machines we send to other planets. I also believe in picking up your trash off the ground and putting it in a wastebasket.


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I agree, Rose. For sure, Mars will sooner or later be thoroughly contaminated by manned missions and bases; but at this stage, contamination could amount to a huge waste of effort, and a disaster for science. It's a calculated risk. One hopes they've done their sums correctly. Of greater concern to me are Europa missions. No one has excluded the possibility of complex life forms in warm oceans under the ice.

What I'd really appreciate is a lecture from a specialist who's studied the contamination aspects.


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Rose, I agree we need to cleanse our probes to the best of our abilities, but I'm not too worried about destroying native life on Mars, or other locations. I'm more worried about contaminating our probes so that we detect the life that we took along instead of the native life.

I don't much think that Earth life would destroy or take over any life on the other planets. The reason I think that is because of the way evolution works. Any life form remains in existence because it can more efficiently process whatever it uses for food and energy than other life forms. So Martian life would be well adapted to living in the extreme, to us, conditions on Mars. Earth life might be adapted to extreme conditions, but not the same extreme conditions that exist on Mars. When we think of invasive species we need to remember that they are species that have migrated from one place on Earth to another that has pretty much the same conditions. Moving into an environment that doesn't even resemble their home location would be pretty unlikely.

And of course having said that I have to also admit that life can be really surprising. We don't really have any way to determine what will really happen if we introduce Earth life to another planet. We just have to go with the odds and make sure we clean our probes as well as we can. After all we will never know if there is life on other planets if we don't go see.

Bill Gill


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I have no difficulty imagining a scenario in which some forms of terrestrial microbes survive and proliferate extremely rapidly in nutrient-rich regions of warm oceans under Europa's ice. Assuming they have a correspondingly high mutation rate, certain aquatic life as may exist there might soon become their hosts, with potentially disastrous results. I would like to be assured that it couldn't happen, and I'd like to know why it couldn't.


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