Science conveniently ignores everything but the iron lumps which, they presume, are pieces of old planets drifting around in space.
Three planets, drifting together in an empty void beyond time and space itself, had been "rotated about their axis."
At first Scarne thought it was a planet, drifting through space free of any sun, but as they loomed closer he saw that it was in fact a planetoid, only a few hundred miles in diameter.
-- --Well, that sets planets drifting free, sure.
It was an uncontrolled and chaotic planet, overgrown and all but ungovernable, a cosmic analog to his own mutated, constantly drifting DNA.
An occasional side-effect is that the occupants see a planet drifting, in miniature, through the hull.
A1 FASHION B15 SCIENCE TIMES F1-12 A Distant Planet Observed Scientists said they had detected the shadow of a planet drifting across the face of a star.
Like a hawk that has spotted something small and fluffy in the grass, like a wandering interstellar flu germ that has just seen a nice blue planet drifting by, Granny turned the stick and plunged down through the choking billows.