# What Earth life could live elsewhere? **URL:** \ **Category:** Factual Questions\ **Created:** [April 28, 2014, 9:10pm UTC](https://boards.straightdope.com/t/what-earth-life-could-live-elsewhere/687215 "2014-04-28T21:10:25Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [April 28, 2014, 9:10pm UTC](https://boards.straightdope.com/t/what-earth-life-could-live-elsewhere/687215/1 "2014-04-28T21:10:25Z")
Inspired in part by the on-going search for life on Mars and elsewhere in the solar system, I’m curious if we know of any life on Earth that could survive elsewhere in the solar system. For example, I know there’s algae that can grow in ice. We have mold in Chernobyl that can use radiation for a sort of photosynthesis. There are sulfur reducers living in boiling hot thermal vents, etc. For the sake of clarity, when I say “live elsewhere” I don’t just mean something that can only survive in a suspended animation state like a bacterial cyst or a tardigrade in hibernation. It has to at least be able to reproduce sufficiently to maintain a stable population (even if it’s a small population, like a single colony). I also don’t mean living in an artificial environment like a space ship, or with needs that have to be constantly fed using something imported from outside the natural environment. If we’re going to seed bacteria on Mars, they’ll have to fend for themselves with what they can find there. And if there are places that we believe could harbor Earth life (say, the depths of Europa) I’m good with that, even if we haven’t been there to verify the conditions in person. ---
**Author:** ![Longshanks](https://avatars.discourse-cdn.com/v4/letter/l/e480ec/32.png) [@Longshanks](https://boards.straightdope.com/u/Longshanks)\ **Post date:** [April 29, 2014, 12:45am UTC](https://boards.straightdope.com/t/what-earth-life-could-live-elsewhere/687215/2 "2014-04-29T00:45:12Z")
Tardigrade. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [April 29, 2014, 1:14am UTC](https://boards.straightdope.com/t/what-earth-life-could-live-elsewhere/687215/3 "2014-04-29T01:14:10Z")
Titan and Europa both potentially offer environments (liquid water, organic molecules, tidal heating) could potentially offer livable habitats to thermophiles. I find it unlikely but it is possible that some terrestrial extremophile might survive on Io. It is possible for some paricularly hardy form of lichen or fungus to survive on Mars provided it is robust enough or can remain partially protected against the high UV environment, but it would also have to have strong nitrogen fixing ability given the apparent lack of nitrates in Martian soil. Stranger ---
**Author:** ![Askance](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/askance/32/8281_2.png) [@Askance](https://boards.straightdope.com/u/Askance)\ **Post date:** [April 29, 2014, 1:41am UTC](https://boards.straightdope.com/t/what-earth-life-could-live-elsewhere/687215/4 "2014-04-29T01:41:44Z")
Supposedly [blue-green algae cold live in the upper atmosphere of Venus](http://www.xenology.info/Xeno/19.2.1.htm), beginning the terraforming process: > [@](#): > > Perhaps inspired by Poul Anderson’s short story entitled “The Big Rain,“ published in 1955, Dr. Carl Sagan in 1961 proposed a terraforming project to modify the environment of Venus. Our sister planet has a hellish climate, with temperatures upwards of 750 °C and pressures of 90 atm at the surface. To prepare it for human habitation it will be necessary to lower the surface temperature and pressure, and to elevate by at least two orders of magnitude the fraction of molecular oxygen present in the atmosphere. Most of the air is carbon dioxide, and this must be eliminated as well. > > Sagan suggests the injection of blue-green algae into the Venusian atmosphere at high altitudes where it is relatively cool. These tiny organisms would consume the CO2 by growing more algae cells with water and aerial nutrients. Molecular oxygen would be expired as a waste product. Over a period of several years the carbon dioxide level begins to drop, thus reducing the green-house effect and cooling the planet overall.2633 When the ground was sufficiently cool, cargo landers armed with fusion bombs could be de-orbited and set down on the surface. These machines, able to burrow like moles and detonate beneath the surface, may be used to trigger new volcanic chains in order to help percolate more water into the dry atmosphere. Eventually the first “big rain“ will fall. Says Sagan: “The heat-retaining clouds will partly clear away, leaving an oxygen-rich atmosphere and a temperature cool enough to sustain hardy plants and animals from Earth.“ > > How reasonable is the astronomer’s proposal? In 1970 a number of biologists conducted experiments to see if earthly algae would actually grow under the extreme initial conditions found on Venus. It was discovered that the most suitable strain is _Cyanidium caldarium_, a single-celled form that is found in hot springs on Earth. This algae produced oxygen vigorously in a hot, high-pressure atmosphere of CO2. In a typical experiment the researchers found that each million algae cells were increasing the oxygen concentration in the test tank by 380% per day. ---
**Author:** ![AK84](https://avatars.discourse-cdn.com/v4/letter/a/85e7bf/32.png) [@AK84](https://boards.straightdope.com/u/AK84)\ **Post date:** [April 29, 2014, 4:00am UTC](https://boards.straightdope.com/t/what-earth-life-could-live-elsewhere/687215/5 "2014-04-29T04:00:36Z")
Did nt some bacteria on a probe survive years on the moon, the probe being brought back by one of the Apollo mission, I think it was Apollo 16? As it is, I have read that bacteria does very well in zero g. ---
**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\ **Post date:** [April 29, 2014, 1:45pm UTC](https://boards.straightdope.com/t/what-earth-life-could-live-elsewhere/687215/6 "2014-04-29T13:45:42Z")
I would think antarctic lichens could make it on Mars. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [April 29, 2014, 2:07pm UTC](https://boards.straightdope.com/t/what-earth-life-could-live-elsewhere/687215/7 "2014-04-29T14:07:26Z")
> [@Enola\_Straight](#): > > I would think antarctic lichens could make it on Mars. Why do you think that? ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [April 29, 2014, 2:30pm UTC](https://boards.straightdope.com/t/what-earth-life-could-live-elsewhere/687215/8 "2014-04-29T14:30:08Z")
> [@AK84](#): > > Didn’t some bacteria on a probe survive years on the moon, the probe being brought back by one of the Apollo mission, I think it was Apollo 16? Apollo 12. This survival is a debatable issue; the returned material from Surveyor 3 might have been contaminated when it returned to Earth. See this wiki article > **[Reports of Streptococcus mitis on the Moon](https://en.wikipedia.org/wiki/Reports_of_Streptococcus_mitis_on_the_Moon#History)** > > As part of the Apollo 12 mission in November 1969, the camera from the Surveyor 3 probe was brought back from the Moon to Earth. On analyzing the camera, it was found that the common bacterium Streptococcus mitis was alive on the camera. NASA reasoned that the camera was not sterilized on Earth before the space probe's launch in April 1967, two and a half years earlier. However, later study showed that the scientists analysing the camera on return to Earth used procedures that were inadequate Si... ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [April 29, 2014, 2:48pm UTC](https://boards.straightdope.com/t/what-earth-life-could-live-elsewhere/687215/9 "2014-04-29T14:48:25Z")
> [@Askance](#): > > Supposedly [blue-green algae cold live in the upper atmosphere of Venus](http://www.xenology.info/Xeno/19.2.1.htm), beginning the terraforming process: The atmosphere of Venus has significant concentrations of sulphur dioxide, hydrogen sulfide, hydrogen chloride, and hydrogen fluoride, all of which would strip the water out of any organism faster than Indiana Jones can kill a tank full of Nazis. Venus is literally the most toxic atmospheric environment in the Solar System and the only way anything could survive there for more than a few minutes is to be snugged inside of a ceramic shell. Stranger ---
**Author:** ![Learjeff](https://avatars.discourse-cdn.com/v4/letter/l/94ad74/32.png) [@Learjeff](https://boards.straightdope.com/u/Learjeff)\ **Post date:** [April 29, 2014, 4:31pm UTC](https://boards.straightdope.com/t/what-earth-life-could-live-elsewhere/687215/10 "2014-04-29T16:31:48Z")
> [@Longshanks](#): > > Tardigrade. What would it eat? According to Wikipedia, they feed on plant cells, algae, and small invertebrates. I assume they also need oxygen, and they definitely need water to be active. Other than that, they’re a good candidate! ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [April 29, 2014, 4:34pm UTC](https://boards.straightdope.com/t/what-earth-life-could-live-elsewhere/687215/11 "2014-04-29T16:34:51Z")
> [@Learjeff](#): > > What would it eat? According to Wikipedia, they feed on plant cells, algae, and small invertebrates. > > I assume they also need oxygen, and they definitely need water to be active. > > Other than that, they’re a good candidate! Yeah, I think this is a limitation that rules out tardigrades actually living anywhere else we know of. They could go dormant and be revived, but I don’t know of anywhere they could actually live and grow. ---
**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\ **Post date:** [April 29, 2014, 4:37pm UTC](https://boards.straightdope.com/t/what-earth-life-could-live-elsewhere/687215/12 "2014-04-29T16:37:04Z")
> [@John\_Mace](#): > > Why do you think that? Well, like Mars, Antarctica is bitter cold and, wen the temps get below freezing, quite dry. IIRC, it actually snows very little down there; most snow just blows in from one place to another. ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [April 29, 2014, 4:37pm UTC](https://boards.straightdope.com/t/what-earth-life-could-live-elsewhere/687215/13 "2014-04-29T16:37:52Z")
> [@Stranger\_On\_A\_Train](#): > > Titan and Europa both potentially offer environments (liquid water, organic molecules, tidal heating) could potentially offer livable habitats to thermophiles. I find it unlikely but it is possible that some terrestrial extremophile might survive on Io. It is possible for some paricularly hardy form of lichen or fungus to survive on Mars provided it is robust enough or can remain partially protected against the high UV environment, but it would also have to have strong nitrogen fixing ability given the apparent lack of nitrates in Martian soil. > > Stranger So it does sound like the moons of the gas giants are probably more hospitable (in places at least) than the nearer planets like Mars. Do you have names for any of the candidate life forms that might survive there? That would give me something to look up for further research. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [April 29, 2014, 4:42pm UTC](https://boards.straightdope.com/t/what-earth-life-could-live-elsewhere/687215/14 "2014-04-29T16:42:31Z")
> [@Enola\_Straight](#): > > Well, like Mars, Antarctica is bitter cold and, wen the temps get below freezing, quite dry. > > IIRC, it actually snows very little down there; most snow just blows in from one place to another. But Mars has no atmosphere (well, next to none) and no magnetic field to shield the planet from the sun’s solar winds and from cosmic rays. Can those life forms survive without an atmosphere?