8 ms·

Life Exists in the Driest Desert on Earth. It Could Exist on Mars, Too

49 points by SirLJ 9y ago

JohnJamesRambo 9y ago
It is very likely life on earth evolved under more optimal conditions and then adapted to drier and more extreme ones. Was Mars ever hospitable enough for long enough for life to evolve is the question.
- thriftwy 9y ago
  Nope! First signs of life are found on Earth in very early minerals that existed under extremely brutal conditions back then. They're also found in oldest parta of crust that we have.
  - blkhawk 9y ago
    well, AFAIK we still have no idea whats actually needed for life to form. Also the conditions for life were better on mars in the past so its entirely possible that life existed and kept on going on mars.
- labster 9y ago
  Nah. The question is if life could feasibly hop from a meteor impact on Earth over to Mars.
  - seszett 9y ago
    That is a lot less likely than the other way round, as the atmosphere of Earth and its greater proximity to the Sun makes it immensely more difficult to launch a rock from the surface all the way to Mars. While a rock launched from the surface of Mars, once it has escaped the planet's gravity well without encountering significant drag from the atmosphere, can just "fall" to Earth.
    - Symmetry 9y ago
      Gaining and losing orbital energy are both equally hard in the vacuum of space, it's not harder to get from Earth's orbit around the Sun to Mars's or vice-versa - though it takes somewhat different amounts of delta-v to go to an Earth-Mars intercept from them. The reason it's easier for ejecta to get from Mars to Earth than vice versa is that Mars has a shallower gravity well to climb out of before making the inter-planetary trip. It's a lot easier for an impact to impart the ~6 km/s velocity you need to get from the surface of Mars to hitting Earth's atmosphere than the ~13 km/s it takes to get from Earth's surface to hitting Mars.
allthenews 9y ago
I do not understand the consistent assumption that life on other planets must take a chemical and physical form similar to our own. Given the myriad of unique chemical compositions and the seemingly infinite ways in which information may be stored and propagated as molecular data, I feel it is myopic to constrain our search for life to such a narrow chemistry. Sure, I understand that given limited resources it is sensible to look for what we know works, but I guess what I'm getting at is that articles which infer potential for life on other planets based on earth-bound extremophiles are probably not as substantial as they may seem. I suppose time will tell.
- blkhawk 9y ago
  If you assume that physics works the same on other planets then carbon-based life is simply the most likely simply from the chemistry we know about. Speculation about say Si based life isn't new but nobody has come up with how that type of organic chemistry might plausibly work.
  - chii 9y ago
    but then, do chemists really know how carbon based life works really? if it weren't for the living examples, wouldn't it be just as hard to work out how proteins form and so on?
    - dogma1138 9y ago
      It isn’t about knowing how carbon life works but understanding basic chemistry which we do. Carbon is the atomic floozy it will hook up with a lot of other elements and can form relatively strong bonds, and it can have upto 4 bonds per carbon atom nominally. This makes carbon the star of its little own chemistry show. Silicon is similar to carbon in this regard which is why it is in the same column in the periodic table however it bonds with fewer elements and it’s chem requires more energy and is often less stable.
      - ethbro 9y ago
zdky 9y ago
As we keep sending probes to Mars, maybe some of the toughest forms of life might be transported to Mars and become Martian before human does
- dbuder 9y ago
  We take a lot of care to avoid this happening.
nukeop 9y ago
Life _could_ exist anywhere, even in deep space, but apparently it doesn't. You could probably interpret some behaviours of neutron stars as life. I admire the human drive to solve the cosmic puzzle, find something bigger and more meaningful than us, but so far it looks like there is only one place in the Universe that has life. And even planets with relatively favourable conditions like Mars are dry, lifeless husks devoid of any, even the simplest lifeforms.
- ythn 9y ago
  Life almost definitely exists elsewhere, and this is coming from a religious person. The number of star/planet combinations out there virtually guarantees it mathematically. The problem is that space is too large and vast and the speed of light too "slow" to be able to reliably "scan" the universe fast enough to find life. Two scenarios (at least): 1. God exists and specifically seeded life on Earth. Even if this is the case there is still no reason meteorites couldn't carry microbes from Earth to Mars. It doesn't seem like God cares about quarantining life to earth, seeing as we made it to the moon. Also, why bother making a universe so mindbogglingly huge and vast only to put life on a single planet? Makes more sense for God to seed countless planets out there with life. And indeed there are a few verses in the Bible that imply Earth is not God's only creation. 2. God does not exist and life emerged naturally. If this is the case then that means life can emerge naturally somewhere else with identical conditions, and given the number of stars/planets/time elapsed, this seems like it could be a high probability (hard to know, though, without understanding exactly how life emerges).
  - nukeop 9y ago
    I've seen this "argument from big numbers" lots of times and it's unconvincing. The large number of planets in the universe means nothing if none of them have Earth-quality conditions, or if it's purposefully kept empty, or if the probability of life arising is too small even given the large number of planets.
  - llccbb 9y ago
    Big numbers don't "guarantee life", rather they make it "very unlikely there isn't life". It is the same way that "an absence of evidence is not evidence of an absence". Secondly, it remains a challenge to categorize and define the envelope for what is and isn't "life". We have a decent hold on "earth-like life" but it will not be sufficient for all that might be encountered in due time (or already exists unbeknownst to us). If you have ever defined an ontology you know that it becomes more and more challenging to put definitions to the universals as you climb up the ontology. At the top, the universal from which all other universals inherit is very commonly left descriptionless. Last, there are many alternative to the Christian One-God view that you express (I am sure you are aware and chose to limit your points for brevity). There are spiritual books that explain/propose/posit the universal disconnect between the living conscious beings of Earth in this material plane and the myriad of "beings" that exist in other higher dimensions/levels/shells.
ohiovr 9y ago
If any kind of life exists on Mars it would have to be unlike anything here. Mars is bathed in peroxides and a whole spectrum of ionizing radation with little to no magnetic field to protect it. https://www.ncbi.nlm.nih.gov/pubmed/11537371 https://www.ncbi.nlm.nih.gov/pubmed/11537371
- simonh 9y ago
  There are many organisms that can tolerate those concentrations of peroxides, and others that can tolerate the radiation exposure aside from the fact that a few inches of soil provides fairly decent protection anyway. From your link: "These results indicate that it is doubtful that the presence of H2O2 alone on Mars would make the surface "self-sterilizing"."
  - ohiovr 9y ago
    Sorry about that, this link from nature is a better angle to the problem (I forgot about perchlorates on Mars). https://www.nature.com/articles/s41598-017-04910-3 https://www.nature.com/articles/s41598-017-04910-3 looks pretty brutal up there
rbanffy 9y ago
Even the driest desert on Earth has more atmosphere than Mars.
joshbaptiste 9y ago
"Why Alien Life Would be our Doom - The Great Filter" Great short video from Kurzgesagt – In a Nutshell https://www.youtube.com/watch?v=UjtOGPJ0URM https://www.youtube.com/watch?v=UjtOGPJ0URM
- popcorncolonel 9y ago
  This is why whenever I see news like this, I get nervous.
- Symmetry 9y ago
  Life arose very quickly on Earth after it cooled down. Photosynthesis took longer and Eukaryotic life took longer still. Seeing a Martian protozoa that evolved independently of Earth life would be scary. Bacterial mats around a thermal vent not so much. https://en.wikipedia.org/wiki/Timeline_of_the_evolutionary_history_of_life https://en.wikipedia.org/wiki/Timeline_of_the_evolutionary_h... EDIT: It's also sort of scary to think that it took 4.5 billion years from the first life for us to evolve, and it's only going to be another billion before the growing sun sterilizes the Earth's surface.
readhn 9y ago
At some point we will be asking ourselves - is it a good idea to bring those alien life samples back to earth for analysis.....

49 points by SirLJ 9y ago

It is very likely life on earth evolved under more optimal conditions and then adapted to drier and more extreme ones. Was Mars ever hospitable enough for long enough for life to evolve is the question.

thriftwy 9y ago
Nope! First signs of life are found on Earth in very early minerals that existed under extremely brutal conditions back then. They're also found in oldest parta of crust that we have.
- blkhawk 9y ago
  well, AFAIK we still have no idea whats actually needed for life to form. Also the conditions for life were better on mars in the past so its entirely possible that life existed and kept on going on mars.
labster 9y ago
Nah. The question is if life could feasibly hop from a meteor impact on Earth over to Mars.
- seszett 9y ago
  That is a lot less likely than the other way round, as the atmosphere of Earth and its greater proximity to the Sun makes it immensely more difficult to launch a rock from the surface all the way to Mars. While a rock launched from the surface of Mars, once it has escaped the planet's gravity well without encountering significant drag from the atmosphere, can just "fall" to Earth.
  - Symmetry 9y ago
    Gaining and losing orbital energy are both equally hard in the vacuum of space, it's not harder to get from Earth's orbit around the Sun to Mars's or vice-versa - though it takes somewhat different amounts of delta-v to go to an Earth-Mars intercept from them. The reason it's easier for ejecta to get from Mars to Earth than vice versa is that Mars has a shallower gravity well to climb out of before making the inter-planetary trip. It's a lot easier for an impact to impart the ~6 km/s velocity you need to get from the surface of Mars to hitting Earth's atmosphere than the ~13 km/s it takes to get from Earth's surface to hitting Mars.

allthenews 9y ago

I do not understand the consistent assumption that life on other planets must take a chemical and physical form similar to our own. Given the myriad of unique chemical compositions and the seemingly infinite ways in which information may be stored and propagated as molecular data, I feel it is myopic to constrain our search for life to such a narrow chemistry. Sure, I understand that given limited resources it is sensible to look for what we know works, but I guess what I'm getting at is that articles which infer potential for life on other planets based on earth-bound extremophiles are probably not as substantial as they may seem. I suppose time will tell.

blkhawk 9y ago
If you assume that physics works the same on other planets then carbon-based life is simply the most likely simply from the chemistry we know about. Speculation about say Si based life isn't new but nobody has come up with how that type of organic chemistry might plausibly work.
- chii 9y ago
  but then, do chemists really know how carbon based life works really? if it weren't for the living examples, wouldn't it be just as hard to work out how proteins form and so on?
  - dogma1138 9y ago
    It isn’t about knowing how carbon life works but understanding basic chemistry which we do. Carbon is the atomic floozy it will hook up with a lot of other elements and can form relatively strong bonds, and it can have upto 4 bonds per carbon atom nominally. This makes carbon the star of its little own chemistry show. Silicon is similar to carbon in this regard which is why it is in the same column in the periodic table however it bonds with fewer elements and it’s chem requires more energy and is often less stable.
    - ethbro 9y ago

zdky 9y ago

As we keep sending probes to Mars, maybe some of the toughest forms of life might be transported to Mars and become Martian before human does

dbuder 9y ago
We take a lot of care to avoid this happening.

nukeop 9y ago

Life _could_ exist anywhere, even in deep space, but apparently it doesn't. You could probably interpret some behaviours of neutron stars as life. I admire the human drive to solve the cosmic puzzle, find something bigger and more meaningful than us, but so far it looks like there is only one place in the Universe that has life. And even planets with relatively favourable conditions like Mars are dry, lifeless husks devoid of any, even the simplest lifeforms.

ythn 9y ago
Life almost definitely exists elsewhere, and this is coming from a religious person. The number of star/planet combinations out there virtually guarantees it mathematically. The problem is that space is too large and vast and the speed of light too "slow" to be able to reliably "scan" the universe fast enough to find life. Two scenarios (at least): 1. God exists and specifically seeded life on Earth. Even if this is the case there is still no reason meteorites couldn't carry microbes from Earth to Mars. It doesn't seem like God cares about quarantining life to earth, seeing as we made it to the moon. Also, why bother making a universe so mindbogglingly huge and vast only to put life on a single planet? Makes more sense for God to seed countless planets out there with life. And indeed there are a few verses in the Bible that imply Earth is not God's only creation. 2. God does not exist and life emerged naturally. If this is the case then that means life can emerge naturally somewhere else with identical conditions, and given the number of stars/planets/time elapsed, this seems like it could be a high probability (hard to know, though, without understanding exactly how life emerges).
- nukeop 9y ago
  I've seen this "argument from big numbers" lots of times and it's unconvincing. The large number of planets in the universe means nothing if none of them have Earth-quality conditions, or if it's purposefully kept empty, or if the probability of life arising is too small even given the large number of planets.
- llccbb 9y ago
  Big numbers don't "guarantee life", rather they make it "very unlikely there isn't life". It is the same way that "an absence of evidence is not evidence of an absence". Secondly, it remains a challenge to categorize and define the envelope for what is and isn't "life". We have a decent hold on "earth-like life" but it will not be sufficient for all that might be encountered in due time (or already exists unbeknownst to us). If you have ever defined an ontology you know that it becomes more and more challenging to put definitions to the universals as you climb up the ontology. At the top, the universal from which all other universals inherit is very commonly left descriptionless. Last, there are many alternative to the Christian One-God view that you express (I am sure you are aware and chose to limit your points for brevity). There are spiritual books that explain/propose/posit the universal disconnect between the living conscious beings of Earth in this material plane and the myriad of "beings" that exist in other higher dimensions/levels/shells.

ohiovr 9y ago

If any kind of life exists on Mars it would have to be unlike anything here. Mars is bathed in peroxides and a whole spectrum of ionizing radation with little to no magnetic field to protect it. https://www.ncbi.nlm.nih.gov/pubmed/11537371 https://www.ncbi.nlm.nih.gov/pubmed/11537371

simonh 9y ago
There are many organisms that can tolerate those concentrations of peroxides, and others that can tolerate the radiation exposure aside from the fact that a few inches of soil provides fairly decent protection anyway. From your link: "These results indicate that it is doubtful that the presence of H2O2 alone on Mars would make the surface "self-sterilizing"."
- ohiovr 9y ago
  Sorry about that, this link from nature is a better angle to the problem (I forgot about perchlorates on Mars). https://www.nature.com/articles/s41598-017-04910-3 https://www.nature.com/articles/s41598-017-04910-3 looks pretty brutal up there

rbanffy 9y ago

Even the driest desert on Earth has more atmosphere than Mars.

joshbaptiste 9y ago

"Why Alien Life Would be our Doom - The Great Filter" Great short video from Kurzgesagt – In a Nutshell https://www.youtube.com/watch?v=UjtOGPJ0URM https://www.youtube.com/watch?v=UjtOGPJ0URM

popcorncolonel 9y ago
This is why whenever I see news like this, I get nervous.
Symmetry 9y ago
Life arose very quickly on Earth after it cooled down. Photosynthesis took longer and Eukaryotic life took longer still. Seeing a Martian protozoa that evolved independently of Earth life would be scary. Bacterial mats around a thermal vent not so much. https://en.wikipedia.org/wiki/Timeline_of_the_evolutionary_history_of_life https://en.wikipedia.org/wiki/Timeline_of_the_evolutionary_h... EDIT: It's also sort of scary to think that it took 4.5 billion years from the first life for us to evolve, and it's only going to be another billion before the growing sun sterilizes the Earth's surface.

readhn 9y ago

At some point we will be asking ourselves - is it a good idea to bring those alien life samples back to earth for analysis.....