6 ms·

It would mean you have a much harder time finding out if Mars once had life, if instead you're detecting mold that hitched a ride with your spacecraft.

by not2b 7y ago

CydeWeys 7y ago
That's fine though. Having a second home for humanity is more important than maximally preserving the ability to detect past life (note that we wouldn't be eliminating that ability, just hindering it somewhat). Also, we think we'd be able to tell pretty easily whether any life detected is from Earth (i.e. we brought it along with us). Life that isn't descended from the same tree of life as us is likely to be radically different.
- andai 7y ago
  Assuming they originated independently, sure. Panspermia (see other comments) suggests that life from one planet might easily end up on another, or that both may originate elsewhere.
- fucking_tragedy 7y ago
  Mars will never be able to be a "second home" for humanity: it lacks the ability to maintain an atmosphere that can support humans due to its weak magnetic field. The bottom of the ocean would be far more habitable if we faced any type of extinction event.
  - bjelkeman-again 7y ago
    It may be possible to create a magnetic field to protect the atmosphere. https://en.m.wikipedia.org/wiki/Terraforming_of_Mars#Protecting_the_atmosphere https://en.m.wikipedia.org/wiki/Terraforming_of_Mars#Protect...
  - ourlordcaffeine 7y ago
    Without the magnetic field, a thick atmosphere on Mars will still persist for tens of thousands of years.
    - fucking_tragedy 7y ago
      It took billions of years for atmospheric oxygen to accumulate on Earth.
      - CydeWeys 7y ago
        Yeah, but most of that was waiting around for oxygen-releasing life to evolve. We could create an oxygen atmosphere on Mars much more quickly than that, because we'd be sending life explicitly for that purpose that's ready now, and we'd also be importing gases and digging up in-situ resources and turning them into gas.
        fucking_tragedy 7y ago
        > Yeah, but most of that was waiting around for oxygen-releasing life to evolve. No, it wasn't. Photosynthesis that released O2 evolved relatively quickly, and was more efficient than other forms of photosynthesis. Then it took another billion years for oxygen to accumulate in the atmosphere. Mind you, we had an entire planet with oceans teeming with photosynthetic life. That will be next to impossible to replicate on Mars. There are two oxygen sinks on Earth that reacted with oxygen released from photosynthesis: the first was the ocean, the other was minerals on land. This is the reason that it took so long for atmospheric oxygen to accumulate. Mars will have a lot of oxidizable minerals and compounds that will react with oxygen before it can accumulate in its atmosphere. Even then, it will escape into space without a sufficient magnetosphere to trap an atmosphere.
  - xvilka 7y ago
    The bottom of European ocean?
    - fucking_tragedy 7y ago
      The bottom of the ocean on Earth.
  - CydeWeys 7y ago
    The lack of a magnetic field ablates away an atmosphere only on cosmic timescales, not human ones. That seems like a problem that could be solved with the benefit of thousands more years of technological development. Never say never. Just a hundred years ago many people argued it was impossible to ever leave the atmosphere of this planet (And it wasn't ... using cannon. The rocket solved that problem).
    - fucking_tragedy 7y ago
      It's a moral hazard to hold out hope for a "home away from home". Terraforming Mars is a moonshot. If we ever find ourselves in a situation where we cannot survive on a planet where food literally grows out of the ground, with abundant liquid water and atmospheric oxygen at 1 atm, how on Earth would we survive on a planet that is devoid of life, has no liquid water, an atmosphere that's 1% the pressure of Earth's with no atmospheric oxygen, and little to no sources of energy? Again, the bottom of the ocean is far more habitable than Mars, even if we experienced a similar extinction event similar to the one we experienced 65 million years ago.
      - stallmanite 7y ago
        What about impacts such as the one that created the moon? We can argue about likelihood of it happening again but large enough impacts can liquify even crust on the opposite side of the planet. The bottom of the ocean won’t help at that point right?
        fucking_tragedy 7y ago
        I mean, the likelihood is pretty important here. The likelihood of such a large impact was pretty high in the early solar system, and it was high for Mars, as well.
      - CydeWeys 7y ago
        That is a different point though. Earth is habitable now. There are plenty of plausible non-anthropogenic disasters that may make that so not so. Some typical examples include megavolcano eruption, coronal mass ejection, and asteroid impact. It would be good to not have all of our eggs in one basket here on Earth. And it's for exactly the same reason of having redundancy that it would be a good thing for Earth to continue to remain habitable, i.e. we should stop ruining the planet through climate change. It's not a moral hazard at all; the two outlooks are congruous.
  - thirstywhimbrel 7y ago
    > The bottom of the ocean would be far more habitable if we faced any type of extinction event. Yeah, space has a coolness factor, and there are things about the origin of the universe we can't learn from the bottom of the ocean, but an underwater station is one of the most underrated projects humanity could pursue. Oceans are phenomenal shields against radiation, extreme weather, or even the temporary combustion of the atmosphere, should things get that bad. The opportunity to learn about groups surviving in isolated habitats, or about megastructures that have to survive hostile external environments, could even provide really useful lessons for space.
thirstywhimbrel 7y ago
I think you're right, this is the best argument against. Kim Stanley Robinson's Mars Trilogy[0] deals with this a great deal, the early scientists pretty quickly devolve into two camps, terraformers and preservationists. There's a lot of other things going on as well, but this is one subplot. At one point in the book, a terraformer made the argument if we discovered life on Mars we'd never know how or when it got there anyway. The monkeys in South America are an interesting parallel - total mystery. Best hunch is that some survivable population "rafted" across the Atlantic at some point - under conditions somehow rare enough to have happened exactly once in 40 million years. KSR doesn't explicitly take a side, but seems to think that terraforming will be inevitable, so we might as well get on with it. On the other hand, Mars may not be terraformable.[1] The challenges there are so extensive as to possibly be insurmountable. Consider that we are so accustomed to certain environmental conditions that changes so subtle as working extended hours in a popcorn factory can give us cancer.[2] Mars just has toxic soil, a low enough gravity as to probably prevent a sustainable atmosphere, and is constantly bombarded with radiation. But who knows, futurism is hard because humanity is pretty ingenious. Isaac Arthur has an extended video on terraforming that's worth watching if you want to dive deeply into this topic.[3] [0] https://en.wikipedia.org/wiki/Mars_trilogy https://en.wikipedia.org/wiki/Mars_trilogy [1] https://en.wikipedia.org/wiki/Terraforming_of_Mars#Challenges_and_limitations https://en.wikipedia.org/wiki/Terraforming_of_Mars#Challenge... [2] https://en.wikipedia.org/wiki/Bronchiolitis_obliterans#Diacetyl https://en.wikipedia.org/wiki/Bronchiolitis_obliterans#Diace... [3] https://www.youtube.com/watch?v=ikoNQNj9ZnU https://www.youtube.com/watch?v=ikoNQNj9ZnU
- benj111 7y ago
  "KSR doesn't explicitly take a side" I don't want to give any spoilers, but the weirdest part of Blue Mars (?) seems to take a side on the existence of life on Mars. Or am I misremembering.
- pvaldes 7y ago
  if we discover life in mars, and is similar to other life on earth we definitely can estimate an evolutive point of fork among both. If the DNA is basically identical in mars and earth, is from earth. There is not a lot of time to accumulate a lot of mutations since 1971

It would mean you have a much harder time finding out if Mars once had life, if instead you're detecting mold that hitched a ride with your spacecraft.

by not2b 7y ago

It would mean you have a much harder time finding out if Mars once had life, if instead you're detecting mold that hitched a ride with your spacecraft.

CydeWeys 7y ago

That's fine though. Having a second home for humanity is more important than maximally preserving the ability to detect past life (note that we wouldn't be eliminating that ability, just hindering it somewhat). Also, we think we'd be able to tell pretty easily whether any life detected is from Earth (i.e. we brought it along with us). Life that isn't descended from the same tree of life as us is likely to be radically different.

andai 7y ago
Assuming they originated independently, sure. Panspermia (see other comments) suggests that life from one planet might easily end up on another, or that both may originate elsewhere.
fucking_tragedy 7y ago
Mars will never be able to be a "second home" for humanity: it lacks the ability to maintain an atmosphere that can support humans due to its weak magnetic field. The bottom of the ocean would be far more habitable if we faced any type of extinction event.
- bjelkeman-again 7y ago
  It may be possible to create a magnetic field to protect the atmosphere. https://en.m.wikipedia.org/wiki/Terraforming_of_Mars#Protecting_the_atmosphere https://en.m.wikipedia.org/wiki/Terraforming_of_Mars#Protect...
- ourlordcaffeine 7y ago
  Without the magnetic field, a thick atmosphere on Mars will still persist for tens of thousands of years.
  - fucking_tragedy 7y ago
    It took billions of years for atmospheric oxygen to accumulate on Earth.
    - CydeWeys 7y ago
      Yeah, but most of that was waiting around for oxygen-releasing life to evolve. We could create an oxygen atmosphere on Mars much more quickly than that, because we'd be sending life explicitly for that purpose that's ready now, and we'd also be importing gases and digging up in-situ resources and turning them into gas.
      - fucking_tragedy 7y ago
        > Yeah, but most of that was waiting around for oxygen-releasing life to evolve. No, it wasn't. Photosynthesis that released O2 evolved relatively quickly, and was more efficient than other forms of photosynthesis. Then it took another billion years for oxygen to accumulate in the atmosphere. Mind you, we had an entire planet with oceans teeming with photosynthetic life. That will be next to impossible to replicate on Mars. There are two oxygen sinks on Earth that reacted with oxygen released from photosynthesis: the first was the ocean, the other was minerals on land. This is the reason that it took so long for atmospheric oxygen to accumulate. Mars will have a lot of oxidizable minerals and compounds that will react with oxygen before it can accumulate in its atmosphere. Even then, it will escape into space without a sufficient magnetosphere to trap an atmosphere.
- xvilka 7y ago
  The bottom of European ocean?
  - fucking_tragedy 7y ago
    The bottom of the ocean on Earth.
- CydeWeys 7y ago
  The lack of a magnetic field ablates away an atmosphere only on cosmic timescales, not human ones. That seems like a problem that could be solved with the benefit of thousands more years of technological development. Never say never. Just a hundred years ago many people argued it was impossible to ever leave the atmosphere of this planet (And it wasn't ... using cannon. The rocket solved that problem).
  - fucking_tragedy 7y ago
    It's a moral hazard to hold out hope for a "home away from home". Terraforming Mars is a moonshot. If we ever find ourselves in a situation where we cannot survive on a planet where food literally grows out of the ground, with abundant liquid water and atmospheric oxygen at 1 atm, how on Earth would we survive on a planet that is devoid of life, has no liquid water, an atmosphere that's 1% the pressure of Earth's with no atmospheric oxygen, and little to no sources of energy? Again, the bottom of the ocean is far more habitable than Mars, even if we experienced a similar extinction event similar to the one we experienced 65 million years ago.
    - stallmanite 7y ago
      What about impacts such as the one that created the moon? We can argue about likelihood of it happening again but large enough impacts can liquify even crust on the opposite side of the planet. The bottom of the ocean won’t help at that point right?
      - fucking_tragedy 7y ago
        I mean, the likelihood is pretty important here. The likelihood of such a large impact was pretty high in the early solar system, and it was high for Mars, as well.
    - CydeWeys 7y ago
      That is a different point though. Earth is habitable now. There are plenty of plausible non-anthropogenic disasters that may make that so not so. Some typical examples include megavolcano eruption, coronal mass ejection, and asteroid impact. It would be good to not have all of our eggs in one basket here on Earth. And it's for exactly the same reason of having redundancy that it would be a good thing for Earth to continue to remain habitable, i.e. we should stop ruining the planet through climate change. It's not a moral hazard at all; the two outlooks are congruous.
- thirstywhimbrel 7y ago
  > The bottom of the ocean would be far more habitable if we faced any type of extinction event. Yeah, space has a coolness factor, and there are things about the origin of the universe we can't learn from the bottom of the ocean, but an underwater station is one of the most underrated projects humanity could pursue. Oceans are phenomenal shields against radiation, extreme weather, or even the temporary combustion of the atmosphere, should things get that bad. The opportunity to learn about groups surviving in isolated habitats, or about megastructures that have to survive hostile external environments, could even provide really useful lessons for space.

thirstywhimbrel 7y ago

I think you're right, this is the best argument against. Kim Stanley Robinson's Mars Trilogy[0] deals with this a great deal, the early scientists pretty quickly devolve into two camps, terraformers and preservationists. There's a lot of other things going on as well, but this is one subplot. At one point in the book, a terraformer made the argument if we discovered life on Mars we'd never know how or when it got there anyway. The monkeys in South America are an interesting parallel - total mystery. Best hunch is that some survivable population "rafted" across the Atlantic at some point - under conditions somehow rare enough to have happened exactly once in 40 million years. KSR doesn't explicitly take a side, but seems to think that terraforming will be inevitable, so we might as well get on with it. On the other hand, Mars may not be terraformable.[1] The challenges there are so extensive as to possibly be insurmountable. Consider that we are so accustomed to certain environmental conditions that changes so subtle as working extended hours in a popcorn factory can give us cancer.[2] Mars just has toxic soil, a low enough gravity as to probably prevent a sustainable atmosphere, and is constantly bombarded with radiation. But who knows, futurism is hard because humanity is pretty ingenious. Isaac Arthur has an extended video on terraforming that's worth watching if you want to dive deeply into this topic.[3] [0] https://en.wikipedia.org/wiki/Mars_trilogy https://en.wikipedia.org/wiki/Mars_trilogy [1] https://en.wikipedia.org/wiki/Terraforming_of_Mars#Challenges_and_limitations https://en.wikipedia.org/wiki/Terraforming_of_Mars#Challenge... [2] https://en.wikipedia.org/wiki/Bronchiolitis_obliterans#Diacetyl https://en.wikipedia.org/wiki/Bronchiolitis_obliterans#Diace... [3] https://www.youtube.com/watch?v=ikoNQNj9ZnU https://www.youtube.com/watch?v=ikoNQNj9ZnU

benj111 7y ago
"KSR doesn't explicitly take a side" I don't want to give any spoilers, but the weirdest part of Blue Mars (?) seems to take a side on the existence of life on Mars. Or am I misremembering.
pvaldes 7y ago
if we discover life in mars, and is similar to other life on earth we definitely can estimate an evolutive point of fork among both. If the DNA is basically identical in mars and earth, is from earth. There is not a lot of time to accumulate a lot of mutations since 1971