Shadow's End: Sheri S. Tepper

On Alliance Central - formerly Earth - nothing breathes but man and wind, and the wind is tamed beneath great domes. From here, humanity rules a vast interstellar empire. When colonists in a remote frontier system are abruptly wiped out by an alien visitation, every team sent to investigate vanishes. At last, a young woman with her disabled son must travel into this devastating silence. For reasons which do become clear, they alone can reach beyond the shadow cast by human civilisation. Cover art by Stephen Bradbury.