In a short story I'm writing, things like this are sent every few hundred years to stars with life. Your species is invited to the galactic community once you can spot it, catch it, and utilize the tech without killing yourself.
As I recall, the original novel is vintage Clarke of the better kind, and then the rest are [co-]authored by some entity named Gentry Lee and basically unreadable.
It is not an unreasonable assumption to make, there are a lot of novel series where the 3rd, 4th, 5th novels are ghostwritten by some third party hired by a publishing company that owns the rights, to cash in on a well known novel's name and author.
The first book is certainly very different from the rest. If not for other reasons then simply because it is a self-standing short novel while later books tell a continuous story spanning three books, with each book being about 2-3 times longer than the first one. Calling them unreadable is a bit harsh though. I still found them to be good sci-fi reading.
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.
>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.
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.
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.
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.
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.
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".
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.
One thing i overlooked earlier is water's propensity to form acids and bases, which support all sorts of useful biological functions. Methane's hydrogen atoms are tightly bound and methane itself is has no dipole moment- meaning it may have the same physical phases as water, but I am skeptical that it could fully support life as a substitute.
...not to mention that you also have to do away with an oxygen rich atmosphere as well...
Places without gravity don't have matter, which makes forming life hard to imagine.
Places with low gravity, such as Io, could easily form life just like Earth did, and would have an easier time to get spaceward if evolution ever got that far.
> 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.
The main question here is not whether Oumuamua was a hydrogen iceberg, but rather whether hydrogen icebergs are possible.
Solid hydrogen is terribly difficult to study [1]. Solid hydrogen does not exist at pressures below 100 GPa (i.e. 1 million times higher than the atmospheric pressure). These pressures occur deep inside Jupiter, for example, but how do you get the "hydrogen iceberg" free?
According to 2020 in science (the Wikipedia article)
Astronomers report that the interstellar object ʻOumuamua (1I/2017 U1) is not likely to have been composed of frozen hydrogen which had been proposed earlier; the compositional nature of the object continues to be unknown.[127][128]
So?
