Today in the history of astronomy, Proxima Centauri’s discoverer is born.

| Published: November 10, 2026

Our Sun and its 10 nearest neighbors are shown in this diagram, with their relative sizes to scale. Credit: Astronomy: Roen Kelly

Born Nov. 10, 1861, in Scotland, Robert Thorburn Ayton Innes would reshape our understanding of our cosmic neighborhood when he discovered our nearest stellar neighbor, Proxima Centauri , in 1912. Innes suspected that Alpha Centauri, a binary system made up of Alpha Centauri A (Rigil Kentaurus) and Alpha Centauri B (Toliman) and then thought to be the nearest stars to Earth (besides the Sun) – had a third member.

The director of the Union Observatory in Johannesburg, South Africa, Innes began a systematic survey for the missing companion star, comparing five years’ worth of photographic plates using a blink-microscope.…