13 thoughts on “Extraterrestrial Life”

  1. You probably should look for it someplace else in the universe, though you might find some sort of life at UC Irvine. 😉

  2. I could imagine that there could be a confusing result if something were found. If species were clearly related to Earth life then was there also a second genesis? And which came from which? If it is clearly different than Earth life, how sure would we be? Might an original self-replicating chemical head down two entirely different paths? Possible. If truly a second genesis then Fermi’s remains a strong paradox. Will there be an MRA world there? If not then what evidence is there that it really ever existed? It’s all very messy.

    Not particularly related but a similar conundrum could be raised with planetary protection. How long must we avoid any potential contact? When will we have explored the last potential niche to confidently say that there is no risk to that life? Ever? If we do find something is it not a threat to every species on Earth including keystone species? How could we ever truly know? If something is there, could we ever be confident that any of all of the microbes that could potentially come from Earth poses no extinction harm to that species or other Martian species that we don’t know about yet? It seems to me that, at some point, we need to make a decision and move ahead and bear with the consequences. I myself favor establishing a permanent base ASAP.

    1. Your statement of the planetary protection quandary is well put. How long must we avoid any potential contact?

      Our current probes have eliminated any possibility of Martian life bigger than microbes. The absence of macroscopic evidence such as limestone formations, stromatolites, etc., makes the presence of life even less likely.

      My answer is proceed with caution but with no presumption that there is Martian life (until we have evidence otherwise).

  3. Did you ever notice on Star Trek Enterprise they decontaminated when returning to the ship (to sex the show up, of course) but never before going to a planet?

  4. A lot of astronomers, planetary scientists, and aerospace people misunderstand the term “extraterrestrial life”.

    There’s terrestrial life, which is the normal amount of life here on Earth. But a few weeks ago I found some green stuff growing on the Philly cream cheese in my refrigerator. That life wasn’t here before. David Attenborough had no idea it existed. It’s extra. Yet it’s still terrestrial because it’s in my refrigerator on planet Earth. It’s extra terrestrial life – adding to the preexisting total.

    And from that comes the word “extraterrestrial.” It’s the green stuff in my fridge.

    Life off Earth would be something like “aterrestrial” or “nonterrestrial”.

  5. A good place to look is to re-analyze the labeled release experiments from Viking, armed with the new knowledge that there is considerable amounts of water on Mars.

  6. I suppose spectroscopic evidence of non-equilibrium conditions on extrasolar planets is the most likely to find something. But theorists are clever, and I bet there are abiotic explanations out there for anything that might be found, so we’re unlikely to ever know for sure.

    For actual Space Aliens(TM), I’ve long wondered if proof would be found when astronauts happen upon a garbage dump from some long-ago expedition that passed through our solar system. No messages, no monoliths, just sandwich wrappers and old newspapers.

    1. As an example, a world that starts with a lot of water, close to a star, can experience photodissocation and loss of hydrogen to space that leaves it with a high pressure oxygen atmosphere. So presence of oxygen and ozone cannot be taken as proof of life.

  7. It’s almost certain that bacterial and viral life is transferred between planets even to other stars (it’s just a question of time and there’s been enough of that. We know material is transferred and we know bacteria can survive the trip.) So I expect we will just need to turn a microscope on a drop of water to find it. It will not matter where on the planet you get that drop of water. We will also know it wasn’t just something we brought with us because it will be different enough to resolve even where on the planet it was found.

    We aren’t really looking to find life, just to confirm it.

    The amazing result would be if it’s not related to earth life, which makes ‘planetary protection’ even more absurd. We could not contaminate that anymore than we could breed horses with cows. Less even.

    1. Most bacteria won’t survive the interplanetary trip. But it only takes one finding a world with compatible chemistry … and lack of competition to kill it off.

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