<adj.all> lightless stars `visible' only to radio antennae
without illumination
<adj.all> came up the lightless stairs the unilluminated side of Mars through dark unlighted (or unlit) streets
Lightless \Light"less\, a. Destitute of light; dark. --Shak.
The vans and cars go lightless in the dark, their cargoes silent and hopeful.
"Into the Abyss" is the series' big finish, with cameras diving a half-mile below the ocean's surface to examine the strange creatures that dwell in the lightless depths.