5 ms·

The Resilience of Life to Astrophysical Events

40 points by sndean 9y ago

dandare 9y ago
>... analysing the most resilient of species–tardigrades. You don't need to kill the tardigrade if all its food is already long dead.
- pdfernhout 9y ago
  Yeah, I was wondering the same thing myself.
  - kbaker 9y ago
    Tardigrades can eat other tardigrades. Boom, infinite life hack unlocked.
    - spartanatreyu 9y ago
      Attach a stick with a powerful magnet to the top of a rocket. The magnet will pull the rocket up. Boom, infinite space travel hack unlocked.
    - pdfernhout 9y ago
      So it's Tardigrades all the way down... :-)
- 13of40 9y ago
  The question is just whether it can eat dead things...
  - VLM 9y ago
    When I read the article in depth, that was basically the plot line of the article, that there is no reasonable astrophysics way to kill off deep ocean vent life therefore they'll always be something to eat. There are some minor mistakes in the article that don't significantly affect the conclusion, such as thinking the boiling point of water at "bottom of the ocean" pressure remains 100C, not in my thermodynamics steam tables... It has certain implications relating to the odds of lower level life on other planets. Even if nothing is living on Mars today, it seems almost certain there's fossilized dead bodies up there. Possibly this is good news WRT soils and future cultivation.
    - amelius 9y ago
      OTOH, if life is resilient to many types of astrophysical event, then this also increases the probability that we've already contaminated Mars with life from Earth.
      - jerf 9y ago
        If it is that easy, nature beat us to it literally billions of years ago: https://en.wikipedia.org/wiki/Panspermia#Lithopanspermia https://en.wikipedia.org/wiki/Panspermia#Lithopanspermia Googling the term "lithopanspermia" can also turn up further interesting discussion. It is good to try our best to sterilize our probes, because our relatively gentle launch and landing and relatively quick transit may enable a lot of things to survive the journey that otherwise couldn't. But there is a point where it stops mattering, because despite what you may think, Earth and Mars are already not fully isolated from each other, so sterilizing beyond that point doesn't change much. One of the exotic possibilities for "how easy is life to start" is that it could still be very hard, but we could find life on Mars and perhaps even throughout the Solar System. But further examination might show that it all sourced from one location. (Which may or may not be Earth in the first place.) So there could be a period of excitement where it looks like life is really easy, only for it to turn out that the evidence remains a sample of one even so. (The most likely way we'd make that determination is that there are certain choices in our biology that are extremely highly conserved, but at the same time, seem arbitrary. For instance, the mapping of what codons map to which amino acids. While there is some fiddling around the edges (as there are several more codons than there are amino acids), the core mappings are highly conserved. If Martian life is based on DNA and has the same core mappings, it probably comes from the same source as Earth life. Another example is protein handedness preferences, though that's stronger in the other direction; a biology with the other handedness would not come from the same source.)
        amelius 9y ago
        This makes me wonder: people say that any goldilocks planet has a high probability of showing life; but why then don't we see different variations of handedness of molecules in Earth's life forms? (or variations in codon mappings)
honestoHeminway 9y ago
If tectonics moves slow enough, and live gets a chance to adapt in a underground bubble, as in - to incooperate new materials- maybe there is live, allready sailing in bubbles over a ocean of magma. After all, life is just statefull storage of energy. Other stuff than carbon can do that.

40 points by sndean 9y ago

>... analysing the most resilient of species–tardigrades. You don't need to kill the tardigrade if all its food is already long dead.

pdfernhout 9y ago
Yeah, I was wondering the same thing myself.
- kbaker 9y ago
  Tardigrades can eat other tardigrades. Boom, infinite life hack unlocked.
  - spartanatreyu 9y ago
    Attach a stick with a powerful magnet to the top of a rocket. The magnet will pull the rocket up. Boom, infinite space travel hack unlocked.
  - pdfernhout 9y ago
    So it's Tardigrades all the way down... :-)
13of40 9y ago
The question is just whether it can eat dead things...
- VLM 9y ago
  When I read the article in depth, that was basically the plot line of the article, that there is no reasonable astrophysics way to kill off deep ocean vent life therefore they'll always be something to eat. There are some minor mistakes in the article that don't significantly affect the conclusion, such as thinking the boiling point of water at "bottom of the ocean" pressure remains 100C, not in my thermodynamics steam tables... It has certain implications relating to the odds of lower level life on other planets. Even if nothing is living on Mars today, it seems almost certain there's fossilized dead bodies up there. Possibly this is good news WRT soils and future cultivation.
  - amelius 9y ago
    OTOH, if life is resilient to many types of astrophysical event, then this also increases the probability that we've already contaminated Mars with life from Earth.
    - jerf 9y ago
      If it is that easy, nature beat us to it literally billions of years ago: https://en.wikipedia.org/wiki/Panspermia#Lithopanspermia https://en.wikipedia.org/wiki/Panspermia#Lithopanspermia Googling the term "lithopanspermia" can also turn up further interesting discussion. It is good to try our best to sterilize our probes, because our relatively gentle launch and landing and relatively quick transit may enable a lot of things to survive the journey that otherwise couldn't. But there is a point where it stops mattering, because despite what you may think, Earth and Mars are already not fully isolated from each other, so sterilizing beyond that point doesn't change much. One of the exotic possibilities for "how easy is life to start" is that it could still be very hard, but we could find life on Mars and perhaps even throughout the Solar System. But further examination might show that it all sourced from one location. (Which may or may not be Earth in the first place.) So there could be a period of excitement where it looks like life is really easy, only for it to turn out that the evidence remains a sample of one even so. (The most likely way we'd make that determination is that there are certain choices in our biology that are extremely highly conserved, but at the same time, seem arbitrary. For instance, the mapping of what codons map to which amino acids. While there is some fiddling around the edges (as there are several more codons than there are amino acids), the core mappings are highly conserved. If Martian life is based on DNA and has the same core mappings, it probably comes from the same source as Earth life. Another example is protein handedness preferences, though that's stronger in the other direction; a biology with the other handedness would not come from the same source.)
      - amelius 9y ago
        This makes me wonder: people say that any goldilocks planet has a high probability of showing life; but why then don't we see different variations of handedness of molecules in Earth's life forms? (or variations in codon mappings)

honestoHeminway 9y ago

If tectonics moves slow enough, and live gets a chance to adapt in a underground bubble, as in - to incooperate new materials- maybe there is live, allready sailing in bubbles over a ocean of magma. After all, life is just statefull storage of energy. Other stuff than carbon can do that.