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If there are microbes on/in Europa, I think they're most likely from Earth. You just need one rock with live microbes to splash into the Europa ocean, and over

If there are microbes on/in Europa, I think they're most likely from Earth. You just need one rock with live microbes to splash into the Europa ocean, and over 4 billion years, many such rocks must have been knocked off Earth.

cmrdporcupine 3y ago
Between here and there is... a lot of cold, vacuum, and extremely intense radiation. I'd be surprised if anything that evolved here could survive the trip.
- fbdab103 3y ago
  Tardigrades can survive in space[0]. > In September last year, a team of scientists launched a squad of tiny animals into space aboard a Russian satellite. Once in orbit, the creatures were shunted into ventilated containers that exposed them to the vacuum of space. In this final frontier, they had no air and they were subjected to extreme dehydration, freezing temperatures, weightlessness and lashings of both cosmic and solar radiation. It’s hard to imagine a more inhospitable environment for life but not only did the critters survive, they managed to reproduce on their return to Earth. [0] https://www.nationalgeographic.com/science/article/tardigrades-become-first-animals-to-survive-vacuum-of-space https://www.nationalgeographic.com/science/article/tardigrad...
  - cmrdporcupine 3y ago
    Yes, but. https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Jupiter_s_radiation_belts_and_how_to_survive_them https://www.esa.int/Enabling_Support/Space_Engineering_Techn... The radiation around Jupiter is... really crazy. Like, not around-orbit-of-earth crazy, way worse.
    - tessierashpool 3y ago
      Deinococcus radiodurans has enough radiation resistance to handle the trip from Mars to Earth (or vice versa). And that's just one we know about. We are very, very far from having ever performed an exhaustive catalog of all bacterial species, let alone one which determined the full range of bacterial radiation resistance.
  - darklycan51 3y ago
    Yes and I believe there was a study about them surviving reentry, and they didn't, regardless if they could survive in space
    - cmrdporcupine 3y ago
      One interesting thing I guess about Europa is that it doesn't really have much of an atmosphere, so I guess re-entry wouldn't be like re-entry to earth. On the other hand, landing on the surface of Europa doesn't get you much. There's likely several km of ice and insane intense radiation before there's possibly anything looking like a habitable zone for earth-life.
      - fbdab103 3y ago
        Compared to decades/centuries in space hitched to a flying object, what's a few kilometers of ice?
  - BurningFrog 3y ago
    I was more thinking fungal or bacterial spores. "Surviving" in harsh environments until they get somewhere nicer is their entire purpose, and they're very good at it.

cmrdporcupine 3y ago

Between here and there is... a lot of cold, vacuum, and extremely intense radiation. I'd be surprised if anything that evolved here could survive the trip.

fbdab103 3y ago
Tardigrades can survive in space[0]. > In September last year, a team of scientists launched a squad of tiny animals into space aboard a Russian satellite. Once in orbit, the creatures were shunted into ventilated containers that exposed them to the vacuum of space. In this final frontier, they had no air and they were subjected to extreme dehydration, freezing temperatures, weightlessness and lashings of both cosmic and solar radiation. It’s hard to imagine a more inhospitable environment for life but not only did the critters survive, they managed to reproduce on their return to Earth. [0] https://www.nationalgeographic.com/science/article/tardigrades-become-first-animals-to-survive-vacuum-of-space https://www.nationalgeographic.com/science/article/tardigrad...
- cmrdporcupine 3y ago
  Yes, but. https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Jupiter_s_radiation_belts_and_how_to_survive_them https://www.esa.int/Enabling_Support/Space_Engineering_Techn... The radiation around Jupiter is... really crazy. Like, not around-orbit-of-earth crazy, way worse.
  - tessierashpool 3y ago
    Deinococcus radiodurans has enough radiation resistance to handle the trip from Mars to Earth (or vice versa). And that's just one we know about. We are very, very far from having ever performed an exhaustive catalog of all bacterial species, let alone one which determined the full range of bacterial radiation resistance.
- darklycan51 3y ago
  Yes and I believe there was a study about them surviving reentry, and they didn't, regardless if they could survive in space
  - cmrdporcupine 3y ago
    One interesting thing I guess about Europa is that it doesn't really have much of an atmosphere, so I guess re-entry wouldn't be like re-entry to earth. On the other hand, landing on the surface of Europa doesn't get you much. There's likely several km of ice and insane intense radiation before there's possibly anything looking like a habitable zone for earth-life.
    - fbdab103 3y ago
      Compared to decades/centuries in space hitched to a flying object, what's a few kilometers of ice?
- BurningFrog 3y ago
  I was more thinking fungal or bacterial spores. "Surviving" in harsh environments until they get somewhere nicer is their entire purpose, and they're very good at it.