5 ms·

I would say, get your head out of your edge cases. Before I go on, I hope you understand no one is saying its not physically possible, and that it absolutely do

I would say, get your head out of your edge cases. Before I go on, I hope you understand no one is saying its not physically possible, and that it absolutely does not exist anywhere in the multiverse, just that if we come across other life, it will most likely be similar to our own. by definition, the most probable form of life in the universe is the 1 we are observing. you only need math and probability to figure that out. We also have observational evidence. As far as we can tell, there is no other life in our solar system. We have 8 other planets and many moons that have failed at creating life in any form - that's literally hundreds of billions of years of failed attempts at life. you can't just pick an element and think its going to work. you need ALL the elements, ALL the states of matter, and the right ratios and amounts of elements to work. Even if you get that lined up, expecting complex life to form under enough pressure to create diamonds in thousands of degrees centigrade also puts the probability of complex life off the table. I don't known who this is hard to understand. in the simplest example as the article states, if you want to fly, there are things that necessitate something that will fly, such as wings. no wings, no fly. sure its POSSIBLE you can fly without wings, but UNLIKELY. given that we have multiple lineages of evolution taking different paths that end up with the same solution is evidence of that.

d0mine 5y ago
You won't see any wings on a hot air balloon. If you think it is not common, look at the fish in the ocean.
- autokad 5y ago
  now you have de-evolved the conversation by trying to change the definition of fly to swim. if you are going to do that, there is no point in continuing the discussion. Furthermore, you are confusing buoyancy with flight.
  - d0mine 5y ago
    Both air & water are fluids (same equations can be applied to many problems). Equating them in the discussion about aliens is not a step too far which it doesn't require much imagination (compare it for example with an idea of a living nebula that might require some knowledge what is entropy, what is life in terms information, etc)
- giantrobot 5y ago
  You don't see a lot of natural hot air balloons floating around do you? Buoyancy in water is different than in air. Lighter than air natural controlled flight, even in a relatively dense atmosphere like Earth or Titan, is highly unlikely. Fish maintain buoyancy with oil in their livers which is a relatively low energy process. Hot air balloons and other LTA vehicles work by having a mean density lower than the containing medium e.g. the atmosphere. Even with Earth's relatively dense atmosphere there's not a lot of lifting gases that are effective without significant heating. Definitely not readily made by biological chemical processes. That leaves thermal balloons. The amount of energy to heat the air in a hot air balloon is pretty significant and requires energy dense fuels. So a hot air balloon animal would need to produce and then burn energy dense hydrocarbons and have a strong yet lightweight natural gas envelope and body structure that could handle the burning of that fuel. Burning I would note at temperatures that would sterilize surfaces.
  - gambiting 5y ago
    >>You don't see a lot of natural hot air balloons floating around do you? Not balloons perhaps, but spiders float on strands of silk using very similar principles. Pollen and seeds frequently use some kind of floating device to spread as far as possible - again, you probably wouldn't call it flying as such, but they can move through the air for the purposes of reproduction without having wings.
    - giantrobot 5y ago
      Floating is not controlled flight. Being blown by the wind due to a high surface area to weight ratio is not flight. I move through the air without wings when I walk. I could jump off a diving board and get some forward motion going. Neither are in any way flight.
      - ncmncm 5y ago
        Anyway, balloons or no, there is a great deal of hot air.
  - ncmncm 5y ago
rendall 5y ago
> get your head out of your edge cases The Earth is the edge case, is the point we're making. All of the conclusions and deductions about what life must be like elsewhere that use Earth as their implicit foundation are going to be overfit to the data, so to speak. Organisms on Earth converge to similar forms: dolphins and fish, bats and birds, for instance, so the form is useful on Earth is a valid observation. Therefore, we can expect to see these forms throughout the Universe is a quite a jump.
- user-the-name 5y ago
  > The Earth is the edge case You do not know that. All available evidence points to the opposite: We have no knowledge, not even a hint, of any other physical process that could sustain life than that of Earth's carbon-based chemistry. The idea that life could take a myriad of different forms is beautiful, but it is pure fantasy, based on no evidence at all.
gambiting 5y ago
>>We have 8 other planets and many moons that have failed at creating life in any form - that's literally hundreds of billions of years of failed attempts at life. Again, how can you be so certain of it? Life could have existed in some form on Mars or Venus or even Mercury millions if not billions of years ago, only to be extinguished by the changing conditions in the solar system and ground to absolute dust by time. Maybe not advanced space faring civilization, but life could have existed in those places and you simply don't know. >> you only need math and probability to figure that out. Yes, and maths and probability are telling me something very opposite to what you are saying. That if you are observing a solar system like ours(forget the entire universe for a second) for a ~100 years out of billions of its existance, then sorry, but you don't know anything about it, certainly not if it harboured life in the past or not, not to a degree that you seem to be certain of.
splitstud 5y ago
So now you're presupposing matter. Look, your myopia is not universal.

d0mine 5y ago

You won't see any wings on a hot air balloon. If you think it is not common, look at the fish in the ocean.

autokad 5y ago
now you have de-evolved the conversation by trying to change the definition of fly to swim. if you are going to do that, there is no point in continuing the discussion. Furthermore, you are confusing buoyancy with flight.
- d0mine 5y ago
  Both air & water are fluids (same equations can be applied to many problems). Equating them in the discussion about aliens is not a step too far which it doesn't require much imagination (compare it for example with an idea of a living nebula that might require some knowledge what is entropy, what is life in terms information, etc)
giantrobot 5y ago
You don't see a lot of natural hot air balloons floating around do you? Buoyancy in water is different than in air. Lighter than air natural controlled flight, even in a relatively dense atmosphere like Earth or Titan, is highly unlikely. Fish maintain buoyancy with oil in their livers which is a relatively low energy process. Hot air balloons and other LTA vehicles work by having a mean density lower than the containing medium e.g. the atmosphere. Even with Earth's relatively dense atmosphere there's not a lot of lifting gases that are effective without significant heating. Definitely not readily made by biological chemical processes. That leaves thermal balloons. The amount of energy to heat the air in a hot air balloon is pretty significant and requires energy dense fuels. So a hot air balloon animal would need to produce and then burn energy dense hydrocarbons and have a strong yet lightweight natural gas envelope and body structure that could handle the burning of that fuel. Burning I would note at temperatures that would sterilize surfaces.
- gambiting 5y ago
  >>You don't see a lot of natural hot air balloons floating around do you? Not balloons perhaps, but spiders float on strands of silk using very similar principles. Pollen and seeds frequently use some kind of floating device to spread as far as possible - again, you probably wouldn't call it flying as such, but they can move through the air for the purposes of reproduction without having wings.
  - giantrobot 5y ago
    Floating is not controlled flight. Being blown by the wind due to a high surface area to weight ratio is not flight. I move through the air without wings when I walk. I could jump off a diving board and get some forward motion going. Neither are in any way flight.
    - ncmncm 5y ago
      Anyway, balloons or no, there is a great deal of hot air.
- ncmncm 5y ago

rendall 5y ago

> get your head out of your edge cases The Earth is the edge case, is the point we're making. All of the conclusions and deductions about what life must be like elsewhere that use Earth as their implicit foundation are going to be overfit to the data, so to speak. Organisms on Earth converge to similar forms: dolphins and fish, bats and birds, for instance, so the form is useful on Earth is a valid observation. Therefore, we can expect to see these forms throughout the Universe is a quite a jump.

user-the-name 5y ago
> The Earth is the edge case You do not know that. All available evidence points to the opposite: We have no knowledge, not even a hint, of any other physical process that could sustain life than that of Earth's carbon-based chemistry. The idea that life could take a myriad of different forms is beautiful, but it is pure fantasy, based on no evidence at all.

gambiting 5y ago

>>We have 8 other planets and many moons that have failed at creating life in any form - that's literally hundreds of billions of years of failed attempts at life. Again, how can you be so certain of it? Life could have existed in some form on Mars or Venus or even Mercury millions if not billions of years ago, only to be extinguished by the changing conditions in the solar system and ground to absolute dust by time. Maybe not advanced space faring civilization, but life could have existed in those places and you simply don't know. >> you only need math and probability to figure that out. Yes, and maths and probability are telling me something very opposite to what you are saying. That if you are observing a solar system like ours(forget the entire universe for a second) for a ~100 years out of billions of its existance, then sorry, but you don't know anything about it, certainly not if it harboured life in the past or not, not to a degree that you seem to be certain of.

splitstud 5y ago

So now you're presupposing matter. Look, your myopia is not universal.