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There are so many questions and so little data. Oumuamua as the space junk of an extra-terrestial society naturally appeals to me even if it's not a legitimate

There are so many questions and so little data. Oumuamua as the space junk of an extra-terrestial society naturally appeals to me even if it's not a legitimate guess (I understand that technological artifact is only a legitimate guess if all other options are exhausted, Ok). One question would be whether the "axiom of mediocrity" implies that Oumuamua's flyby of the sun was not the object's first flyby. Logically, if objects that can survive a million encounter with stars exist, they would seem a million times more common than objects that could survive one. Which would also be why you'd be more likely to find space junk than a working space craft.

perl4ever 6y ago
>Logically, if objects that can survive a million encounter with stars exist, they would seem a million times more common than objects that could survive one That doesn't seem quite right. Wouldn't they be a million times more common relative to their overall proportion in the universe? Durable objects could be, say, one in a million, cancelling out the probability.
- joe_the_user 6y ago
  I mean "all else being equal", of course all else might not be equal. The thing is that I don't think objects need to be that durable to survive for a long time in space.
beamatronic 6y ago
Would an advanced star-faring society make a spacecraft out of anything other than objects that are already moving? Asteroids and such. This way you don’t have to lift any mass out of a gravity well.
- CarbyAu 6y ago
  I absolutely don't know much, so question here: Why is it assumed that a "star faring society" must originate from a place of significant gravity? I can understand heat and some way to gather the required chemicals (primordial ooze) together is required. But does it require much gravity really?
  - zdragnar 6y ago
    Well, life as we know it relies on carbon (energy storage), oxygen (energy activation) and liquid water (oxygen and chemical transfer). Setting aside the quandary of sufficient mass to support life evolution and development from 0 => faster-than-light (or some other interstellar) travel, there's the problem of liquid water. The lower the pressure it is under, the more quickly it will evaporate or even boil. Not only that, but dissolved gasses within the water will also boil out. So, we're left with either imagining some means of having a large quantity and volume of mass configured in a way that maintains pressure without gravity, OR identifying an alternative set of chemicals for the properties that carbon, oxygen and water currently fulfill. Water is especially useful due to being a dipole, and there are several other known compounds that are as well, but they are significantly more complex. I'm definitely not super informed in this area, but my understanding is there really aren't other options that are readily found in nature in regular quantities.
    - CarbyAu 6y ago
      Oh! Thank you so much for that, my mind figuratively went Ding! While I mentioned "primordial ooze" I was thinking of ooze as a random assortment of elements we may or may not know much about as my "keep your mind open to possibilities" attitude left it vague. But by defining the Ooze(especially with probabilities of elements in the universe) you define the requirements - mainly liquid water. And then conditions by which you have to keep a blob of water together and liquid in the harshness of space are more apparent. As you say, in theory you could come up with weird physical structures to keep water liquid and together; or some other chemistry to fulfill the same roles. But in practice, probability says "Liquid Water + Gravity".
    - ajuc 6y ago
      I've read a sci-fi story set on a cold planet where methane was fulfilling the role of water. There were methane rivers, seas, it was falling in rain, and it was the basis for all the chemistry. It sounded reasonable, but I'm not good enough with science to know if it was legit.
      - 6y ago
- ALittleLight 6y ago
  Tough to say without knowing the relative costs of acceleration and building a spaceship out of an asteroid when using advanced and alien technology.
  - marcusverus 6y ago
    Important point. For us, as a type 0 / type I civilization, accelerating a large asteroid strikes us as an absurdly energy-intensive operation. But then, moving a ton of cargo from Pennsylvania to California was an absurdly energy-intensive operation in the year 1800. 50 years later it was easy. For a civilization that is approaching type II status or beyond, the energy required to accelerate an asteroid is likely trivial. [0]https://en.wikipedia.org/wiki/Kardashev_scale https://en.wikipedia.org/wiki/Kardashev_scale
- deleted 6y ago
  [deleted]
garmaine 6y ago
> Logically, if objects that can survive a million encounter with stars exist, they would seem a million times more common than objects that could survive one. That’s not how the statistics work.

perl4ever 6y ago

>Logically, if objects that can survive a million encounter with stars exist, they would seem a million times more common than objects that could survive one That doesn't seem quite right. Wouldn't they be a million times more common relative to their overall proportion in the universe? Durable objects could be, say, one in a million, cancelling out the probability.

joe_the_user 6y ago
I mean "all else being equal", of course all else might not be equal. The thing is that I don't think objects need to be that durable to survive for a long time in space.

beamatronic 6y ago

Would an advanced star-faring society make a spacecraft out of anything other than objects that are already moving? Asteroids and such. This way you don’t have to lift any mass out of a gravity well.

CarbyAu 6y ago
I absolutely don't know much, so question here: Why is it assumed that a "star faring society" must originate from a place of significant gravity? I can understand heat and some way to gather the required chemicals (primordial ooze) together is required. But does it require much gravity really?
- zdragnar 6y ago
  Well, life as we know it relies on carbon (energy storage), oxygen (energy activation) and liquid water (oxygen and chemical transfer). Setting aside the quandary of sufficient mass to support life evolution and development from 0 => faster-than-light (or some other interstellar) travel, there's the problem of liquid water. The lower the pressure it is under, the more quickly it will evaporate or even boil. Not only that, but dissolved gasses within the water will also boil out. So, we're left with either imagining some means of having a large quantity and volume of mass configured in a way that maintains pressure without gravity, OR identifying an alternative set of chemicals for the properties that carbon, oxygen and water currently fulfill. Water is especially useful due to being a dipole, and there are several other known compounds that are as well, but they are significantly more complex. I'm definitely not super informed in this area, but my understanding is there really aren't other options that are readily found in nature in regular quantities.
  - CarbyAu 6y ago
    Oh! Thank you so much for that, my mind figuratively went Ding! While I mentioned "primordial ooze" I was thinking of ooze as a random assortment of elements we may or may not know much about as my "keep your mind open to possibilities" attitude left it vague. But by defining the Ooze(especially with probabilities of elements in the universe) you define the requirements - mainly liquid water. And then conditions by which you have to keep a blob of water together and liquid in the harshness of space are more apparent. As you say, in theory you could come up with weird physical structures to keep water liquid and together; or some other chemistry to fulfill the same roles. But in practice, probability says "Liquid Water + Gravity".
  - ajuc 6y ago
    I've read a sci-fi story set on a cold planet where methane was fulfilling the role of water. There were methane rivers, seas, it was falling in rain, and it was the basis for all the chemistry. It sounded reasonable, but I'm not good enough with science to know if it was legit.
    - 6y ago
ALittleLight 6y ago
Tough to say without knowing the relative costs of acceleration and building a spaceship out of an asteroid when using advanced and alien technology.
- marcusverus 6y ago
  Important point. For us, as a type 0 / type I civilization, accelerating a large asteroid strikes us as an absurdly energy-intensive operation. But then, moving a ton of cargo from Pennsylvania to California was an absurdly energy-intensive operation in the year 1800. 50 years later it was easy. For a civilization that is approaching type II status or beyond, the energy required to accelerate an asteroid is likely trivial. [0]https://en.wikipedia.org/wiki/Kardashev_scale https://en.wikipedia.org/wiki/Kardashev_scale
deleted 6y ago
[deleted]

garmaine 6y ago

> Logically, if objects that can survive a million encounter with stars exist, they would seem a million times more common than objects that could survive one. That’s not how the statistics work.