On The Large Asteroid

Poul Anderson, The Stars Are Also Fire, 26.

Edmond Beynac's hypothesis:

"'...a planetoid massive enough to form a core...'" (p. 342);

the planetoid was smashed in a collision;

Jovian gravity perturbed most of the fragments into the Kuiper Belt.

Implications:

during four or more billion years, further collisions between the fragments and between them and comets;

the largest body, the former core, over a quarter of the mass of Luna, would attract more collisions;

low radiation and temperature preserve volatiles better than in the inner Solar System;

on the other hand, when a comet strikes, radiation causes cometary organic material to form larger molecules;

because shards of the colliding bodies would not have welded totally, the interior will have many caverns and tunnels.

Coral-like protrusions are possibly impact gobbets that solidified and welded together soon after they landed. The absence of a crater at this site suggests that the impact occurred when the planetoid was still hot and plastic. Also, it would still have been near Jupiter because a strong magnetic field would have made the gouts move along converging arcs. A molten sheet thrown sideways solidified over a crevasse. The Lunarian, Ilitu, jumping onto the sheet, falls through it and into the crevasse. The text had presented several indications that the explorers were being incautious and that yet another unforeseeable accident in an unfamiliar environment was imminent.