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>Seveneves belongs in the subgenre of hard science fiction, which means it emphasizes scientific accuracy. Everything adheres to physical laws, so unlike Star W

>Seveneves belongs in the subgenre of hard science fiction, which means it emphasizes scientific accuracy. Everything adheres to physical laws, so unlike Star Wars, no one travels anywhere near the speed of light. A pity then that a little basic chemistry eluded both the writer and the critic - there's no carbon on the moon. Rather difficult to support humans, and carry out feats of biotechnology, without it...

JacobJans 10y ago
What do you mean? In the book, the moon explodes and destroys the world. Pretty much the exact opposite of supporting humans.
- drakenot 10y ago
  I'm guessing you haven't read it then? I don't want the spoil the ending but your parent post makes sense.
- dbcooper 10y ago
  My understanding is that the surviving humans shelter in "the cleft", which is a fragment of the moon. They then use biotechnology techniques to repopulate. Even when limited to the biotech operations, they would need a lot of carbon based materials. Keith Robison has some thoughts on it: http://omicsomics.blogspot.co.nz/2015/12/thoughts-on-synthetic-biology-of.html http://omicsomics.blogspot.co.nz/2015/12/thoughts-on-synthet...
ef4 10y ago
They did bring tons of comet with them. Which could theoretically be a source of carbon. It's a stretch, of course. But I think the story was that they kept the population in the Cleft down to a few hundred for many generations, only growing beyond that once people began venturing further afield. At that point, carbonaceous asteroids are not implausibly hard to get -- from high orbit, you've already paid most of the delta V needed to get elsewhere in the inner solar system, if you've got a lot of time to spend.
djloche 10y ago
The book goes into great depth and makes "rather difficult to support humans" the focus of the entire first 2 parts of the book. Space is indeed rather difficult to support humans. The third part of the book is a 'what if they actually survived and continued to survive, fast forward 5000 years". In reality, there would be no survivors in left space, but I appreciated the final third part of the book all the same because I enjoy the fiction part of science fiction just as much as I do the science part.
dingo_bat 10y ago
Hard scifi usually has an unrealistic premise but everything else is constrained by real science that we know. If everything was exactly adherent to science and tech as it currently exists, it wouldn't be science fiction. It would just be fiction.
a_bonobo 10y ago
IMHO, "hard SF" has developed as a term for books that have "hard physics", everything else like biology, chemistry, sometimes even mathematics is usually lacking. As an example: The Cheela, the microscopic intelligent life forms in the more famous hard SF Dragon's Egg, are described like eukaryotes with an eukaryotic life style, but they're so tiny that they don't need any of the complex "inventions" of eukaryotes, for example, they wouldn't need any "plumbing" in the body since they're small enough for diffusion to deliver nutrients. IRC their DNA is triple stranded; DNA is double stranded so that it's more safe from mutations as you can always read the opposite from the opposite strand, if you had a second backup in the form of a third strand you would have no stable chemical bonds between the bases. Triple helices exist but these doesn't help with stability and are implicated in transcription. Edit: Similarly, there should be massive problems in the later communication because the Cheela shouldn't have a base 10 mathematical system as they don't have 10 fingers, you could still display it as base 10 but there has to be a conversion (see https://www.quora.com/What-does-one-mean-by-Every-base-is-base-10 https://www.quora.com/What-does-one-mean-by-Every-base-is-ba... ).
rtkwe 10y ago
That was covered at least in passing. The comet they capture and use to reach the Cleft provides the sources of carbon and other elements that are hard to get. Presumably long enough to build and launch slow missions to capture and redirect other sources (happens 'off screen'). > "The black stuff has all kind of goodies on it. Carbon, obviously. But also nitrogen, ptoassium---" "Micronutrients," Markus said, "that the Cloud Ark will be needing."
- knodi123 10y ago
  but isn't it all poisoned by those pesky radioactive flea particles? Or was that problem only insurmountable due to the limited resources of the comet expedition?
  - rtkwe 10y ago
    The fleas caused a lot of problems even during the Great Ride but I imagine once they were in the Cleft they'd be able to figure out a way to process it to remove the contamination. it wasn't covered in the book though that I remember.
    - obbybreeden 10y ago
      There was a passage where they had rigged the robots to pick out debris from the ice. I think they would eventually be able to pick out the hotter bits out of the ice as well.
tlb 10y ago
There's some carbon on the moon. Rock samples are reported as having on the order of 100 ppm carbon [1]. That means that the amount of carbon in a human body is found in 100 m^3 of lunar soil. So if you extract all the carbon from the top meter of regolith, you could cover the moon with humans on a 10 meter grid spacing. [1] https://www.hq.nasa.gov/alsj/a15/LunarSampleCompendium15265.pdf https://www.hq.nasa.gov/alsj/a15/LunarSampleCompendium15265....
Symmetry 10y ago
I think we're supposed to assume they went out and got more carbon somehow. It would have made more sense if they'd carried the comet parts into the cleft but I'm willing to forgive it. Of course the physics of the moon blowing up are totally wrong but I'm willing to swallow a single impossible thing and keep going. http://hopefullyintersting.blogspot.com/2015/06/seveneves-and-roche-limit.html http://hopefullyintersting.blogspot.com/2015/06/seveneves-an...

JacobJans 10y ago

What do you mean? In the book, the moon explodes and destroys the world. Pretty much the exact opposite of supporting humans.

drakenot 10y ago
I'm guessing you haven't read it then? I don't want the spoil the ending but your parent post makes sense.
dbcooper 10y ago
My understanding is that the surviving humans shelter in "the cleft", which is a fragment of the moon. They then use biotechnology techniques to repopulate. Even when limited to the biotech operations, they would need a lot of carbon based materials. Keith Robison has some thoughts on it: http://omicsomics.blogspot.co.nz/2015/12/thoughts-on-synthetic-biology-of.html http://omicsomics.blogspot.co.nz/2015/12/thoughts-on-synthet...

ef4 10y ago

They did bring tons of comet with them. Which could theoretically be a source of carbon. It's a stretch, of course. But I think the story was that they kept the population in the Cleft down to a few hundred for many generations, only growing beyond that once people began venturing further afield. At that point, carbonaceous asteroids are not implausibly hard to get -- from high orbit, you've already paid most of the delta V needed to get elsewhere in the inner solar system, if you've got a lot of time to spend.

djloche 10y ago

The book goes into great depth and makes "rather difficult to support humans" the focus of the entire first 2 parts of the book. Space is indeed rather difficult to support humans. The third part of the book is a 'what if they actually survived and continued to survive, fast forward 5000 years". In reality, there would be no survivors in left space, but I appreciated the final third part of the book all the same because I enjoy the fiction part of science fiction just as much as I do the science part.

dingo_bat 10y ago

Hard scifi usually has an unrealistic premise but everything else is constrained by real science that we know. If everything was exactly adherent to science and tech as it currently exists, it wouldn't be science fiction. It would just be fiction.

a_bonobo 10y ago

IMHO, "hard SF" has developed as a term for books that have "hard physics", everything else like biology, chemistry, sometimes even mathematics is usually lacking. As an example: The Cheela, the microscopic intelligent life forms in the more famous hard SF Dragon's Egg, are described like eukaryotes with an eukaryotic life style, but they're so tiny that they don't need any of the complex "inventions" of eukaryotes, for example, they wouldn't need any "plumbing" in the body since they're small enough for diffusion to deliver nutrients. IRC their DNA is triple stranded; DNA is double stranded so that it's more safe from mutations as you can always read the opposite from the opposite strand, if you had a second backup in the form of a third strand you would have no stable chemical bonds between the bases. Triple helices exist but these doesn't help with stability and are implicated in transcription. Edit: Similarly, there should be massive problems in the later communication because the Cheela shouldn't have a base 10 mathematical system as they don't have 10 fingers, you could still display it as base 10 but there has to be a conversion (see https://www.quora.com/What-does-one-mean-by-Every-base-is-base-10 https://www.quora.com/What-does-one-mean-by-Every-base-is-ba... ).

rtkwe 10y ago

That was covered at least in passing. The comet they capture and use to reach the Cleft provides the sources of carbon and other elements that are hard to get. Presumably long enough to build and launch slow missions to capture and redirect other sources (happens 'off screen'). > "The black stuff has all kind of goodies on it. Carbon, obviously. But also nitrogen, ptoassium---" "Micronutrients," Markus said, "that the Cloud Ark will be needing."

knodi123 10y ago
but isn't it all poisoned by those pesky radioactive flea particles? Or was that problem only insurmountable due to the limited resources of the comet expedition?
- rtkwe 10y ago
  The fleas caused a lot of problems even during the Great Ride but I imagine once they were in the Cleft they'd be able to figure out a way to process it to remove the contamination. it wasn't covered in the book though that I remember.
  - obbybreeden 10y ago
    There was a passage where they had rigged the robots to pick out debris from the ice. I think they would eventually be able to pick out the hotter bits out of the ice as well.

tlb 10y ago

There's some carbon on the moon. Rock samples are reported as having on the order of 100 ppm carbon [1]. That means that the amount of carbon in a human body is found in 100 m^3 of lunar soil. So if you extract all the carbon from the top meter of regolith, you could cover the moon with humans on a 10 meter grid spacing. [1] https://www.hq.nasa.gov/alsj/a15/LunarSampleCompendium15265.pdf https://www.hq.nasa.gov/alsj/a15/LunarSampleCompendium15265....

Symmetry 10y ago

I think we're supposed to assume they went out and got more carbon somehow. It would have made more sense if they'd carried the comet parts into the cleft but I'm willing to forgive it. Of course the physics of the moon blowing up are totally wrong but I'm willing to swallow a single impossible thing and keep going. http://hopefullyintersting.blogspot.com/2015/06/seveneves-and-roche-limit.html http://hopefullyintersting.blogspot.com/2015/06/seveneves-an...