Mars is my Destination by Frank Belknap Long

There was only one small window in Trilling's office. But I could see that the sky outside was still bright with stars, and the glimmer of the ceiling lamp made the metal surface above us seem to fall away and dissolve into a much wider expanse of star-studded space.

The ceiling-mirrored image of the lamp itself looked like the Sun, blazing in noonday brightness directly overhead and out beyond were galaxies and super-galaxies strung like beads on a wire across the great curve of the universe.