“It’s an inert chunk of rock, orbiting in the vast wastes of interplanetary space.”
An inert chunk of rounded rock. What would be an explanation of the eroded and rounded profile?
Two possibilities come quickly to mind ...
1) It may be more like a pile of rubble than a single chunk. Its own gravity would tend to make it round. I recall other objects turning out to be like that.
2) Eons of impacts from smaller objects may have blasted off all the rough edges.