I am trying to remember the title of a scifi story.

While traveling FTL, passengers would see an optical illusion of a row composed of multiple images of themselves in an orderly straight line extending off into the horizon.

There were similar lines to the rear, the left, and the right.
Disturbingly some of the images were different. Different clothing, haircuts, etc. And some images were missing, leaving gaps.

Images are from branching timelines. Gaps are time lines where you died