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I am fascinated about how less we know overall about the earth, and the solar system. I would not be surprised if we found life in the solar system. May not b

I am fascinated about how less we know overall about the earth, and the solar system. I would not be surprised if we found life in the solar system. May not be advanced, but multi cellular life. I mean life as it was on earth some 10,000 years ago, with early humans and all. Edit: Sorry I shared my fictitious fascination. It would probably make a good movie, humans finding pre-historic humans on Titan or Europa.

lachlan-sneff 8y ago
Early humans were pretty damn advanced, at least in terms of biology.
contravariant 8y ago
I would be surprised if even our concept of cells translates that easily. Unless of course both forms of life share the same origin, but that just raises more questions.
- Balero 8y ago
  I think it might work quite well actually. They could certainly not work with any of the biological systems as ours, such as proteins and fats etc. But I think it is likely that there would be internal subdivisions in a complex life-form. This is however likening, branches in trees, to cells in an organism, to crystals in a rock.
- jerf 8y ago
  Cells are a pretty fundamental structure. Sci-fi can have fun with undifferentiated masses of protoplasm like The Blob, but there's a lot of reasons to expect that cell walls are going to be pretty fundamental on one level or another. Without them, instead of isolating the task of giving permission to enter and exit the life form to one structure, everything in the life form has to be capable of doing so. It is exceedingly unlikely that this is a good trade. I would also say that before you start drawing up crazy ideas about alternate structures that you should check your own body first; we already have a lot of variants on the theme! Blood is a liquid that has a lot of cells in it. There's a lot of other such circulatory fluids that have cells within them, but are not "cellular" in the sense that they contain nothing but cells. White blood cells do interesting things with cell walls, as does the immune system in general. Cells have structure well beyond just little cubes already, like nerve cells, etc. Personally I find that when one tries to come up with some funny sci-fi idea for an alternate life form, either A: it's physically implausible or B: something, somewhere on Earth is already doing something very like it, and I don't see middle ground very often.
- TangoTrotFox 8y ago
  This is the thing I also always wonder about. Consider that about 60% of a banana's DNA is shared with us. And for cats it's 90%. That's just really stupefying to think about. But the more important point here is that I think it is literally impossible for us to even imagine what life that had no genetic similarity to us would even begin to be like. We just have no basis for comparison whatsoever since we are all so closely related. Though yeah, genetic similarity implying exogenesis would also be an equally interesting result. Would that similarity be organic/natural in nature, or might we just be some species' lab experiment? Perhaps they seeded us with their same genetic origins to discover more about their own evolution and development. This is an experiment I'm certain we'll eventually carry out ourselves. So many interesting possibilities.
  - jacobush 8y ago
    But how quickly did they get started in that case? I mean, the ago of the Earth is quite a nice chunk out of the timeline since the Universe got started.
    - TangoTrotFox 8y ago
      200,000 years ago we did not exist as a species. 2500 years ago stabbing each other with iron weapons was literally cutting edge technology. In the past 200 years we have invented: production automobile, airplanes, space flight, launched probes into interstellar space, computers, the internet, ... We have discovered relativity, quantum mechanics, galaxies, ... Assuming we are able to survive, imagine where we'll be in 200k years. Actually you can't. It's just impossible to even begin to try to imagine that. On that scale we'll likely have even begun to experience evolutionary speciation as we settle different regions of space and end up with extended periods of relative isolation. And now consider that this entire timeline is but 400k years. That's not even a blink in the eye of the cosmos.
      - deleted 8y ago
        [deleted]
      - jacobush 8y ago
Balero 8y ago
I would be very surprised to see life anything like life on earth 10,000 years ago in our solar system. No planet in our solar system can support that level of bio diversity. They are either too hot, small, cold. Additionally none of them have the right mix of atmospheric gases. Plants massively changed the makeup of Earth's atmosphere, some hundreds of millions of years ago, before the first animals on land. I think there is a chance of very simple life on some moons of the gas giants, if they turn out to have liquid water. Most likely this would be single cell organisms (which can grow quite large, a few inches even) or basic multicellular life. I would be shocked if we found life like trilobites, or even simple plants. It would be the biggest discovery of our lifetime.
- jacobush 8y ago
  The watery moons are really interesting. Consider this - if we dumped a few tons of (earth originated) diverse bio-matter inside and on these moons, I would be shocked if not some of the earthen critters couldn't if not thrive, at least gain a foothold in these moons. I mean, considering we find microbes in the weirdest places here on Earth. So - given that they could live in these moons: if there is life there already, is it related to Earth life? If not, why not? If there is no life there, but we could seed these moons, how come they are not seeded already? (From meteorite ejecta etc.)
  - Balero 8y ago
    Oh almost certainly! Earth grown animals have been found alive on the outside of space stations [0]. Dumping a bunch of earth stuff in these places would likely lead to a new ecosystem. So long as there was an energy source, like thermal vents. This is actually a major problem for looking for life elsewhere in the solar system. How do we know it isn't just an Earth grown hitchhiker? Instruments sent to other planets have to be thoroughly cleaned. In theory they could have been seeded as you describe. The problem is, to quote Douglas Arthur, that "space is really, really big"[1]. It's also not great for life, even the hardiest Earth animals can only survive for decades, and it could easily be centuries or millenia until they were deposited anywhere. Additionally the gas giants, due to their mass, act as a big attractor to stray mass. And any biological life adrift is likely to be sucked into one of these, rather than land on an orbiting moon. [0]https://en.wikipedia.org/wiki/Tardigrade https://en.wikipedia.org/wiki/Tardigrade [1]https://en.wikipedia.org/wiki/The_Hitchhiker%27s_Guide_to_the_Galaxy https://en.wikipedia.org/wiki/The_Hitchhiker%27s_Guide_to_th... fiction, doesn't back up any point. But hilarious and correct about the size of space.
Symmetry 8y ago
I think it's helpful to look at a timeline of life on Earth when thinking about that issue. http://hopefullyintersting.blogspot.com/2018/03/the-drake-equation-again.html http://hopefullyintersting.blogspot.com/2018/03/the-drake-eq... Life's gone through a lot of changes over the time it's around. 10,000 years ago there were already humans and the Neolithic revolution was well underway and agriculture was just starting. Multicellular life was one of the big revolutions but eukaryotes and before that photosynthesis seem to have taken a very long time to evolve. Interestingly we don't have a lower bound for how long it took life to arise once the Earth's surface started having liquid water, so maybe very simple life is pretty common.
WhompingWindows 8y ago
Your timeframe of 10,000 years ago as "multicellular life" and "early humans and all" is WAY off. There have been human-like animals for 2 million years, there have been multicellular life forms for probably a few billion.

lachlan-sneff 8y ago

Early humans were pretty damn advanced, at least in terms of biology.

contravariant 8y ago

I would be surprised if even our concept of cells translates that easily. Unless of course both forms of life share the same origin, but that just raises more questions.

Balero 8y ago
I think it might work quite well actually. They could certainly not work with any of the biological systems as ours, such as proteins and fats etc. But I think it is likely that there would be internal subdivisions in a complex life-form. This is however likening, branches in trees, to cells in an organism, to crystals in a rock.
jerf 8y ago
Cells are a pretty fundamental structure. Sci-fi can have fun with undifferentiated masses of protoplasm like The Blob, but there's a lot of reasons to expect that cell walls are going to be pretty fundamental on one level or another. Without them, instead of isolating the task of giving permission to enter and exit the life form to one structure, everything in the life form has to be capable of doing so. It is exceedingly unlikely that this is a good trade. I would also say that before you start drawing up crazy ideas about alternate structures that you should check your own body first; we already have a lot of variants on the theme! Blood is a liquid that has a lot of cells in it. There's a lot of other such circulatory fluids that have cells within them, but are not "cellular" in the sense that they contain nothing but cells. White blood cells do interesting things with cell walls, as does the immune system in general. Cells have structure well beyond just little cubes already, like nerve cells, etc. Personally I find that when one tries to come up with some funny sci-fi idea for an alternate life form, either A: it's physically implausible or B: something, somewhere on Earth is already doing something very like it, and I don't see middle ground very often.
TangoTrotFox 8y ago
This is the thing I also always wonder about. Consider that about 60% of a banana's DNA is shared with us. And for cats it's 90%. That's just really stupefying to think about. But the more important point here is that I think it is literally impossible for us to even imagine what life that had no genetic similarity to us would even begin to be like. We just have no basis for comparison whatsoever since we are all so closely related. Though yeah, genetic similarity implying exogenesis would also be an equally interesting result. Would that similarity be organic/natural in nature, or might we just be some species' lab experiment? Perhaps they seeded us with their same genetic origins to discover more about their own evolution and development. This is an experiment I'm certain we'll eventually carry out ourselves. So many interesting possibilities.
- jacobush 8y ago
  But how quickly did they get started in that case? I mean, the ago of the Earth is quite a nice chunk out of the timeline since the Universe got started.
  - TangoTrotFox 8y ago
    200,000 years ago we did not exist as a species. 2500 years ago stabbing each other with iron weapons was literally cutting edge technology. In the past 200 years we have invented: production automobile, airplanes, space flight, launched probes into interstellar space, computers, the internet, ... We have discovered relativity, quantum mechanics, galaxies, ... Assuming we are able to survive, imagine where we'll be in 200k years. Actually you can't. It's just impossible to even begin to try to imagine that. On that scale we'll likely have even begun to experience evolutionary speciation as we settle different regions of space and end up with extended periods of relative isolation. And now consider that this entire timeline is but 400k years. That's not even a blink in the eye of the cosmos.
    - deleted 8y ago
      [deleted]
    - jacobush 8y ago

Balero 8y ago

I would be very surprised to see life anything like life on earth 10,000 years ago in our solar system. No planet in our solar system can support that level of bio diversity. They are either too hot, small, cold. Additionally none of them have the right mix of atmospheric gases. Plants massively changed the makeup of Earth's atmosphere, some hundreds of millions of years ago, before the first animals on land. I think there is a chance of very simple life on some moons of the gas giants, if they turn out to have liquid water. Most likely this would be single cell organisms (which can grow quite large, a few inches even) or basic multicellular life. I would be shocked if we found life like trilobites, or even simple plants. It would be the biggest discovery of our lifetime.

jacobush 8y ago
The watery moons are really interesting. Consider this - if we dumped a few tons of (earth originated) diverse bio-matter inside and on these moons, I would be shocked if not some of the earthen critters couldn't if not thrive, at least gain a foothold in these moons. I mean, considering we find microbes in the weirdest places here on Earth. So - given that they could live in these moons: if there is life there already, is it related to Earth life? If not, why not? If there is no life there, but we could seed these moons, how come they are not seeded already? (From meteorite ejecta etc.)
- Balero 8y ago
  Oh almost certainly! Earth grown animals have been found alive on the outside of space stations [0]. Dumping a bunch of earth stuff in these places would likely lead to a new ecosystem. So long as there was an energy source, like thermal vents. This is actually a major problem for looking for life elsewhere in the solar system. How do we know it isn't just an Earth grown hitchhiker? Instruments sent to other planets have to be thoroughly cleaned. In theory they could have been seeded as you describe. The problem is, to quote Douglas Arthur, that "space is really, really big"[1]. It's also not great for life, even the hardiest Earth animals can only survive for decades, and it could easily be centuries or millenia until they were deposited anywhere. Additionally the gas giants, due to their mass, act as a big attractor to stray mass. And any biological life adrift is likely to be sucked into one of these, rather than land on an orbiting moon. [0]https://en.wikipedia.org/wiki/Tardigrade https://en.wikipedia.org/wiki/Tardigrade [1]https://en.wikipedia.org/wiki/The_Hitchhiker%27s_Guide_to_the_Galaxy https://en.wikipedia.org/wiki/The_Hitchhiker%27s_Guide_to_th... fiction, doesn't back up any point. But hilarious and correct about the size of space.

Symmetry 8y ago

I think it's helpful to look at a timeline of life on Earth when thinking about that issue. http://hopefullyintersting.blogspot.com/2018/03/the-drake-equation-again.html http://hopefullyintersting.blogspot.com/2018/03/the-drake-eq... Life's gone through a lot of changes over the time it's around. 10,000 years ago there were already humans and the Neolithic revolution was well underway and agriculture was just starting. Multicellular life was one of the big revolutions but eukaryotes and before that photosynthesis seem to have taken a very long time to evolve. Interestingly we don't have a lower bound for how long it took life to arise once the Earth's surface started having liquid water, so maybe very simple life is pretty common.

WhompingWindows 8y ago

Your timeframe of 10,000 years ago as "multicellular life" and "early humans and all" is WAY off. There have been human-like animals for 2 million years, there have been multicellular life forms for probably a few billion.