On this day in space! Oct. 13, 1773: Astronomer Charles Messier discovers the Whirlpool Galaxy before we ever knew it was a galaxy
space.com Oct 13, 2026

On this day in space! Oct. 13, 1773: Astronomer Charles Messier discovers the Whirlpool Galaxy before we ever knew it was a galaxy

AI-summarised brief · reviewed before publication

On October 13, 1773 French astronomer Charles Messier recorded a fuzzy object now known as the Whirlpool Galaxy (M 51) while compiling a list of non‑comet sightings to aid comet hunters. Messier catalogued it as the 51st entry but could not discern its spiral form or recognize it as a galaxy. Seventy‑two years later William Parsons identified its whirlpool shape, mistaking it for a spiral nebula, and Edwin Hubble later confirmed its true nature as an external galaxy. Located roughly 31 million light‑years away in the constellation Venatici, M 51 shines at magnitude 8.4 and is visible with modest telescopes. Modern observations show its striking arms result from a gravitational interaction with the nearby galaxy NGC 5195, which likely spurred a burst of star formation.

💡 Why It Matters

  • · The galaxy’s discovery illustrates how early cataloguing efforts unintentionally paved the way for recognizing galaxies beyond the Milky Way, reshaping our cosmic perspective.