"Regions of outward migration allow planets and planetoids to survive, " Mac Low said.
麦克·劳说：“向外迁移的地区使行星和小行星得以生存。”
2
Others are irregular fragments of such planetoids brought about by collisions.
其他一些星体则是由小行星碰撞产生的不规则碎片组成。
3
A simulated low-speed crash between comparably sized planetoids yields a Pluto and a Charon, plus an icy debris disk that could coalesce into a Nix and a Hydra.