The Men and the Mirror

On the surface of a runaway planet hurtling toward the sun, caught in the vast concavity of a nearly frictionless mirror a thousand miles in diameter, they slid across and back, across and back, like toys at the merdy of some cosmic child. And they were running out of air. But the mirror was only NEARLY frictionless, so that at the end of each pass the found themselves a tantalizing ten feet further from escape at the mirrir's rim. It might just as well have been ten light-years, for all their lives were worth.