# Life on Mars

**URL:** <https://boards.straightdope.com/t/life-on-mars/757933>\
**Category:** Factual Questions\
**Created:** [June 21, 2016, 1:27am UTC](https://boards.straightdope.com/t/life-on-mars/757933 "2016-06-21T01:27:00Z")\
**Posts on this page:** 20\
**Page:** 1

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**Author:** ![Vicsage](https://avatars.discourse-cdn.com/v4/letter/v/e68b1a/32.png) [@Vicsage](https://boards.straightdope.com/u/Vicsage)\
**Post date:** [June 21, 2016, 1:27am UTC](https://boards.straightdope.com/t/life-on-mars/757933/1 "2016-06-21T01:27:00Z")

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Its been 50 years since the Vikings landed on Mars. They did experiments to see if there was life there. The experiments at first seemed to say yes, but after further analysis the vast majority of scientists said the results were most likely a chemical reaction and not signs of life. Yet since then, we’ve landed multiple crafts there and not one has tried to duplicate Vikings search for life with better tests for life that would fix the problems of a chemical reaction mimicking life. Why? They just keep looking for water or proof that water existed in the past. We know that water existed in the past. Why did they stop looking for life?

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**Author:** ![dolphinboy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dolphinboy/32/330_2.png) [@dolphinboy](https://boards.straightdope.com/u/dolphinboy)\
**Post date:** [June 21, 2016, 1:34am UTC](https://boards.straightdope.com/t/life-on-mars/757933/2 "2016-06-21T01:34:50Z")

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Because there is none there. How many times do they have to try to prove it to you?

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**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:** [June 21, 2016, 2:02am UTC](https://boards.straightdope.com/t/life-on-mars/757933/3 "2016-06-21T02:02:59Z")

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What makes the o.p. believe that “we” (e.g. NASA) has stopped looking for signs of life on Mars? In fact, several instruments on the Mars Science Laboratory (MSL, a.k.a. “Curisosity”) are specifically designed to look for organic molecules and precursors, both to look for signs of fossil or extant life as well as to evaluate the suitability of Mars for future habitation.

However, because of its thin atmosphere and lack of magnetosphere, the surface of Mars is scroched by ultraviolet radiation and charged particles emitted by the Sun, making it an uninhabitable place for any form of life analgous to what we have on Earth. Our hardiest micro-organisms would do well to survive even a few hours on Mars, even under shade from direct sunlight. If there is any existing microscopic life on Mars it is buried under centimeters of Martian soil, and it is unlikely that complex, multicellular life ever existed on Mars; if so, it was faint and fleeting, and left no evidence of the kind we leave ourselve, and that despite the complete lack of tectonic movement

Stranger

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**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\
**Post date:** [June 21, 2016, 3:33am UTC](https://boards.straightdope.com/t/life-on-mars/757933/4 "2016-06-21T03:33:54Z")

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> [@dolphinboy](#):
>
> Because there is none there. How many times do they have to try to prove it to you?

How do you prove a negative?

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**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\
**Post date:** [June 21, 2016, 3:49am UTC](https://boards.straightdope.com/t/life-on-mars/757933/5 "2016-06-21T03:49:48Z")

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> [@dolphinboy](#):
>
> Because there is none there. How many times do they have to try to prove it to you?

Unless you have information not available to the rest of us, this is not a GQ answer.

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**Author:** ![tullsterx](https://avatars.discourse-cdn.com/v4/letter/t/e9bcb4/32.png) [@tullsterx](https://boards.straightdope.com/u/tullsterx)\
**Post date:** [June 21, 2016, 4:05am UTC](https://boards.straightdope.com/t/life-on-mars/757933/6 "2016-06-21T04:05:56Z")

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I check that series out on Netflix but just couldn’t get into it. No wonder it was canceled.

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**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\
**Post date:** [June 21, 2016, 4:39am UTC](https://boards.straightdope.com/t/life-on-mars/757933/7 "2016-06-21T04:39:27Z")

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> [@Stranger\_On\_A\_Train](#):
>
> However, because of its thin atmosphere and lack of magnetosphere, the surface of Mars is scroched by ultraviolet radiation and charged particles emitted by the Sun, making it an uninhabitable place for any form of life analgous to what we have on Earth. Our hardiest micro-organisms would do well to survive even a few hours on Mars, even under shade from direct sunlight.

I’ll bet [tardigrades](https://en.wikipedia.org/wiki/Tardigrade) can do just fine there. That’s what all those rovers should be digging for.

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**Author:** ![Lucas\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lucas_jackson/32/303_2.png) [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)\
**Post date:** [June 21, 2016, 4:50am UTC](https://boards.straightdope.com/t/life-on-mars/757933/8 "2016-06-21T04:50:30Z")

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It’s true! I heard they love scroch!

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**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\
**Post date:** [June 21, 2016, 5:07am UTC](https://boards.straightdope.com/t/life-on-mars/757933/9 "2016-06-21T05:07:04Z")

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Is there any love at all for the idea that there is life on Mars…now…carried there by insufficiently sterilized landers?

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**Author:** ![AK84](https://avatars.discourse-cdn.com/v4/letter/a/85e7bf/32.png) [@AK84](https://boards.straightdope.com/u/AK84)\
**Post date:** [June 21, 2016, 6:34am UTC](https://boards.straightdope.com/t/life-on-mars/757933/10 "2016-06-21T06:34:01Z")

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> [@Stranger\_On\_A\_Train](#):
>
> However, because of its thin atmosphere and lack of magnetosphere, the surface of Mars is scroched by ultraviolet radiation and charged particles emitted by the Sun, making it an uninhabitable place for any form of life analgous to what we have on Earth. Our hardiest micro-organisms would do well to survive even a few hours on Mars, even under shade from direct sunlight. If there is any existing microscopic life on Mars it is buried under centimeters of Martian soil, and it is unlikely that complex, multicellular life ever existed on Mars; if so, it was faint and fleeting, and left no evidence of the kind we leave ourselve, and that despite the complete lack of tectonic movement
> 
> Stranger

Which does raise the question though, would we be able to recognize exotic not earth style life as life when we see it as opposed to weird rocks or minerals?

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**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:** [June 21, 2016, 6:42am UTC](https://boards.straightdope.com/t/life-on-mars/757933/11 "2016-06-21T06:42:01Z")

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> [@Senegoid](#):
>
> I’ll bet [tardigrades](https://en.wikipedia.org/wiki/Tardigrade) can do just fine there. That’s what all those rovers should be digging for.

And how would a water-dwelling tactopod evolve on a barren, nearly vacuum surface with only sporadic liquid water?

> [@Trinopus](#):
>
> Is there any love at all for the idea that there is life on Mars…now…carried there by insufficiently sterilized landers?

The landers are as thoroughly sterilized as any object ever manufactured, but for all that, the potential for contamination by Earth-bourne microoganisms is not inconsequential. However, sending human astronauts to explore Mars ensures that the microorganisms which infest us and crawl over every surface we touch will definitely contaminate samples and the general environment.

Stranger

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**Author:** ![bardos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bardos/32/1069_2.png) [@bardos](https://boards.straightdope.com/u/bardos)\
**Post date:** [June 21, 2016, 7:12am UTC](https://boards.straightdope.com/t/life-on-mars/757933/12 "2016-06-21T07:12:28Z")

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> [@Vicsage](#):
>
> Its been 50 years since the Vikings landed on Mars.

I know it’s been proven that the Vikings landed in America way before Columbus, but are you asserting that they also reached Mars?

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**Author:** ![Carl\_Pham](https://avatars.discourse-cdn.com/v4/letter/c/e9a140/32.png) [@Carl\_Pham](https://boards.straightdope.com/u/Carl_Pham)\
**Post date:** [June 21, 2016, 8:18am UTC](https://boards.straightdope.com/t/life-on-mars/757933/13 "2016-06-21T08:18:27Z")

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The original Viking experiments were inconclusive because no one understood aerochemistry well enough. One assumes NASA planners have decided not to repeat that mistake. Hence, they are studying the chemistry of the Martian surface. While they’re at it, they are trying to figure out the Martian water cycle, since for excellent general reasons it seems unlikely that life can exist without the use of liquid water. One thing the Viking experiments made clear is the the Martian surface is not _teeming_ with life. Hence to find it, if it exists, you probably have to be very clever about where you look. The probes since Viking have attempted to build up that ability to be clever.

As for why they don’t just throw a life-chemistry experiment aboard anyway, every now and then, just for grins – the answer is that mass on a craft bound for Mars is very, very, very expensive. There are always far more instruments competing for that precious mass than can be accommodated. There is already a brutal scientific death cage match triage process that winnows them down to the few that are the most general and important. Nobody is going to throw something on board that doesn’t have a 100% chance of returning valuable data.

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**Author:** ![cmdrpiffle](https://avatars.discourse-cdn.com/v4/letter/c/b4bc9f/32.png) [@cmdrpiffle](https://boards.straightdope.com/u/cmdrpiffle)\
**Post date:** [June 21, 2016, 1:44pm UTC](https://boards.straightdope.com/t/life-on-mars/757933/14 "2016-06-21T13:44:21Z")

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Its been 40 years, not 50…

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**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\
**Post date:** [June 21, 2016, 2:33pm UTC](https://boards.straightdope.com/t/life-on-mars/757933/15 "2016-06-21T14:33:00Z")

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All I know is it’s a god-awful small affair to the girl with the mousey hair.

Anyway, on a more serious note, there’s this:

ExoMars probe set to sniff out signs of life on the Red Planet

> **[ExoMars probe set to sniff out signs of life on the Red Planet](https://www.newscientist.com/article/2079697-exomars-probe-set-to-sniff-out-signs-of-life-on-the-red-planet/)**
>
> The joint European-Russian mission carries the most sensitive instruments ever sent to look for potentially biological gases on Mars

> [@](#):
>
> On 14 March the ExoMars Trace Gas Orbiter (TGO) will blast off from the Baikonur Cosmodrome in Kazakhstan aboard a Proton rocket. Its mission: to understand the planet’s atmosphere and search for signs of biological and geological activity.

After that article was written, the spacecraft did launch successfully.

There will be a second craft launched in 2020 as part of the ExoMars mission. Wikipedia has more details here:

> **[ExoMars](https://en.wikipedia.org/wiki/ExoMars)**
>
> ExoMars (Exobiology on Mars) is an astrobiology programme of the European Space Agency (ESA).
> The goals of ExoMars are to search for signs of past life on Mars, investigate how the Martian water and geochemical environment varies, investigate atmospheric trace gases and their sources and, by doing so, demonstrate the technologies for a future Mars sample-return mission.
> The first part of the programme is a mission launched in 2016 that placed the Trace Gas Orbiter into Mars orbit and release...

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**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\
**Post date:** [June 21, 2016, 2:37pm UTC](https://boards.straightdope.com/t/life-on-mars/757933/16 "2016-06-21T14:37:23Z")

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> [@cmdrpiffle](#):
>
> Its been 40 years, not 50…

And only 21 Martian years.

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**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\
**Post date:** [June 21, 2016, 2:52pm UTC](https://boards.straightdope.com/t/life-on-mars/757933/17 "2016-06-21T14:52:47Z")

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> [@Vicsage](#):
>
> [snip] … We know that water existed in the past. Why did they stop looking for life?

Do you have a citation that we knew liquid water existed on Mars _before_ the recent series of rovers? My understanding is that this was one of the experiments on the rovers was to look at the rocks, and we found them to be of a type that only forms in the presence of liquid water, thus we know _now_ that liquid water most likely did exist there. Plus the rovers moved over to some shelf-like structures and they seem to be sedimentary rocks.

We’re also looking for fossils, that would qualify as “looking for life” I should think.

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**Author:** ![XT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xt/32/456_2.png) [@XT](https://boards.straightdope.com/u/XT)\
**Post date:** [June 21, 2016, 3:59pm UTC](https://boards.straightdope.com/t/life-on-mars/757933/18 "2016-06-21T15:59:06Z")

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> [@Vicsage](#):
>
> Its been 50 years since the Vikings landed on Mars. They did experiments to see if there was life there. The experiments at first seemed to say yes, but after further analysis the vast majority of scientists said the results were most likely a chemical reaction and not signs of life. Yet since then, we’ve landed multiple crafts there and not one has tried to duplicate Vikings search for life with better tests for life that would fix the problems of a chemical reaction mimicking life. Why? They just keep looking for water or proof that water existed in the past. We know that water existed in the past. Why did they stop looking for life?

Are you asking why we didn’t perform the same tests that the Viking probes did on Mars, or are you asserting that NASA hasn’t continued to explore for life on Mars since Viking? If the later you are simply wrong…NASA has in fact pursued several different lines of exploration to each not just for life on Mars but for water, part of their follow the water strategy for looking for life. The thing is, if NASA can find liquid water on Mars, that would be a good place to do more in-depth targeted searches for life. If they can find evidence of early water that would be a good place to search for ancient traces of life. So, by searching for water, both today and in the past it’s part of their strategy to continue to look for life on Mars…and this isn’t their only strategy or the only thing they are doing.

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**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:** [June 21, 2016, 4:58pm UTC](https://boards.straightdope.com/t/life-on-mars/757933/19 "2016-06-21T16:58:39Z")

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> [@watchwolf49](#):
>
> Do you have a citation that we knew liquid water existed on Mars _before_ the recent series of rovers? My understanding is that this was one of the experiments on the rovers was to look at the rocks, and we found them to be of a type that only forms in the presence of liquid water, thus we know _now_ that liquid water most likely did exist there. Plus the rovers moved over to some shelf-like structures and they seem to be sedimentary rocks.
> 
> We’re also looking for fossils, that would qualify as “looking for life” I should think.

Geologists have strongly suspected that various features on the Martian surface show signs of being formed by the flow of liquid water since the original imagery from Mariner 6 and 7 flybys, and the higher fidelity imagery from the Viking orbiters made geologists pretty confident that liquid water flow had occurred at various points during the history of Mars surface. Both the NASA Mars Odyssey and ESA Mars Express missions were specifically looking for the “missing” water which was expected to be found on Mars.

Neither the Spirit and Opportunity or Curiosity rovers are specifically looking for ‘fossils’, and the expectation that life may have existed or could still exist is predominately focused on microscopic and most likely single cell (or the xenobiological equivalent) life. The possibility for life on Mars to have developed into multicellular or macroscopic forms in the presumably short period where the surface may have been openly habitable to non-extremophile life is thought to be too short to support the complex evolutionary steps to achieve more complicated stages of evolutionary development. We may, of course, be surprised by what we find–in fact, we very much would like to be suprised and discover new insights from a novel source of life independent of Earth that revise our thinking and models of evolutionary development–but we’re currently largely looking for the detritus and waste products that we would expect to be produced by living organisms; in other words, we’re looking through their graveyards and cesspools.

To extend upon what **Carl Pham** said about the process of deciding what scientific equipment was included on “Curiousity” to support the most preferred experiements, it is little mentioned the amount of engineering effort and ingenuity that went into the rover. It is, in fact, one of the most complex and densely instrumented mobile platforms ever built by man. The level of effort that went into developing and qualifying the Mars Science Laboratory is actually comparable to the original development of the atomic bomb (minus the extraordinary effort to fabricate and refine weapons-grade uranium, of course). The rover represents thousands of person-years of effort by some of the smartest people in their pertinant fields, and they did so with the recognition that they had only one chance to get it right; once the rocket which carried the rover and its orbit-to-surface delivery system lifted off, it either worked or it didn’t. I know people love the idea of astronauts walking around leaving footprints and planting flags, but in terms of organizational and technical proficiency, the magnitude and completeness of the development, design, and testing effort for the rover is, as the kids say, redonkulous and amazeballs.

If we could be this smart and capable in other areas of technology development we’d have nuclear energy production that is compact and produces almost no waste; satellite communications and observaton systems that would be able to let you call from remotest Tanzania to Manhattan and be able to track your nanny taking the kids for a stroll; effective treatments and eradication of many common infectious agents; highly energy efficient automobiles which can go for hundreds of thousands of miles without major service, et cetera. This \<1000 kg rover is the equivalent of several terrestrial laboratories, providing a massive stream of data to hundreds of teams of planetary scientists, chemists, and exobiologists. It is a device that would have been pure science fiction to scientists of the previous generation, and it has operated continuously on the harsh surface of another planet without any maintenance for going on four years. And it has done so for an end-to-end mission cost of less than a single _Virginia_-class attack submarine or approximately 1% of the cheapest and most risky crewed mission.

Stranger

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<div class="post-metadata">

**Author:** ![joema](https://avatars.discourse-cdn.com/v4/letter/j/a9adbd/32.png) [@joema](https://boards.straightdope.com/u/joema)\
**Post date:** [June 21, 2016, 5:51pm UTC](https://boards.straightdope.com/t/life-on-mars/757933/20 "2016-06-21T17:51:05Z")

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> [@Stranger\_On\_A\_Train](#):
>
> …I know people love the idea of astronauts walking around leaving footprints and planting flags, but…This \<1000 kg rover is the equivalent of several terrestrial laboratories, providing a massive stream of data to hundreds of teams of planetary scientists, chemists, and exobiologists…And it has done so for an end-to-end mission cost of less than…1% of the cheapest and most risky crewed mission…

Since it has been recently discovered that Mars is coated with calcium perchlorate, a chemical toxic to human life, this makes human exploration even more difficult.

Astronauts on the moon were covered in lunar dust – it was embedded in their suits, their hair, under their fingernails, etc:

[http://www.nasa.gov/images/content/327385main\_dustcoveredastronaut.jpg](http://www.nasa.gov/images/content/327385main_dustcoveredastronaut.jpg)  
[http://msnbcmedia.msn.com/i/MSNBC/Components/Slideshows/\_production/ss-121206-apollo-17-anniversary/ss-121206-apollo-17-10.jpg](http://msnbcmedia.msn.com/i/MSNBC/Components/Slideshows/_production/ss-121206-apollo-17-anniversary/ss-121206-apollo-17-10.jpg)

Similar dust exposure on Mars would likely kill them, even if a tiny amount was inhaled. This also makes it very difficult to grow crops in Mars soil since the perchlorate would bio-accumulate in the tissue of vegetables.

> **[Toxic Mars dust could hamper planned human missions](https://www.newscientist.com/article/dn23505-toxic-mars-dust-could-hamper-planned-human-missions/)**
>
> The latest finds from robot explorers are boosting fears that fine-grained toxins in Martian dust will be hazardous to human explorers – and tough to avoid

These problems could technically be solved, e.g, astronauts could use a full-body “glove box” as shown on the 1971 film Andromeda Strain. However this would further increase the cost and risk, plus limit mobility:

[![](https://www.oocities.org/hazmatgirl/galleries/images/andromeda_strain.jpg) ](https://www.oocities.org/hazmatgirl/galleries/images/andromeda_strain.jpg)  
[http://blog.modernmechanix.com/mags/PopularScience/3-1954/hot\_suit.jpg](http://blog.modernmechanix.com/mags/PopularScience/3-1954/hot_suit.jpg)

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