[3am]

It will turn into a cloud of asteroids surrounding the earth intended to prevent the human race from unleashing whatever hell we create with those autonomous mining robots on the ISS (would be my guess, at least). Feel like the agent/patient distinction is pretty blunt foreshadowing against it being a survival/resilience story against and abstract antagonist like a random natural disaster.

edit: http://www.amazon.com/Seveneves-A-Novel-Neal-Stephenson/dp/0... gives a bit more detail and it is likely it will not become a ring. Probably a lot of highly energetic reentrant debris capable of generating a lot of atmospheric heat.

edit: @jaquesm - i'm allowing for creative license, and was making guess explaining what would happened based on my gut feel for the plot direction. you're probably correct on the physics.

[jacquesm]

That's at odds with what I understand of the celestial mechanics of the earth-moon system, roughly the same thing happened to Saturn and even though the rings have thickness they are relatively thin compared to their width.

What reason would there be for the moon debris to form a cloud, that would require a lot of energy added to the pieces after the initial collision to get them to go into other orbits? (I'm sure Stephenson has researched this but it makes no sense to me at first sight.)

The options really are quite limited, re-unification in a 'lump', one or more large chunks escaping earth orbit or a ring, I don't see how a cloud is possible.

All but the second would result in quite a bit of debris landing on earth as the debris from the collisions would be scattered in all directions.

[jhallenworld]

Energy was added, so I'm sure it will be a dynamic mess..

On the other hand, the moon is beyond earth's Roche limit so I don't think the final result will be rings.

Also what is the tensile strength of the center of the moon? I'm not sure it's possible to have 7 large non-spheroidal shaped pieces, but google suggests ~800 km is the lower limit for rocky bodies, so maybe it's just possible.

[jhallenworld]

I'm going with the Wool Omnibus theory: we find out that someone on earth did it on purpose.