Darkness, not brightness, is the honest default of interstellar space. Every direction holds stars, yet each star is so far away that its flux at a wandering planet falls to a whisper of photons, spread thin by inverse‑square dilution and intercepted across an almost vanishing solid angle.
The popular hunch is simple. Fill the sky with stars and the void should blaze. Physics disagrees because luminosity competes with distance: double the distance and the same energy must cover four times the area, so intensity crashes. Between stars stretch enormous light‑years of low‑density gas and dust; that material scatters and absorbs some radiation, but the bigger effect is pure geometry, the way a finite star shrinks to a near‑point on a black dome.
The deeper claim is that even an infinite, star‑filled universe would not necessarily glow like a photosphere to a lonely world. Astronomers know this puzzle as Olbers paradox and answer it with expansion of space and a finite age for stellar burning, which together redshift and dilute distant light so much that many stars never contribute visible photons at all. Human vision then finishes the job, with retinal thresholds that simply ignore the feeble drizzle that remains, leaving a planet adrift in a crowd it can barely see.
