Massive space mirrors could be 40 times brighter than the full moon, astronomers warn. ‘It will be worse than big cities like London’
space.com Aug 26, 2026

Massive space mirrors could be 40 times brighter than the full moon, astronomers warn. ‘It will be worse than big cities like London’

AI-summarised brief · reviewed before publication

A U.S. startup, Reflect Orbital, plans to launch 40,000 large sun‑reflecting mirrors into low Earth orbit. A study by Princeton astrophysicist Gaspar Bakos shows each mirror would appear 40 times brighter than the full moon, erasing stars for observers within a 3‑mile beam and brightening the sky beyond that distance. The company’s first satellite, EARENDIL‑1, will carry a 60‑by‑60‑foot mirror to test nighttime solar power and emergency illumination. The FCC’s approval has sparked backlash from astronomers, environmental groups, and aviation stakeholders concerned about widespread light pollution.

💡 Why It Matters

  • · The mirrors could create a permanent twilight over large swaths of Earth, disrupting night‑time ecosystems and scientific observations.
  • · Their deployment threatens to alter the night sky for future generations.