Brief
Charles Messier catalogues Whirlpool Galaxy on Oct. 13 1773
Messier listed the spiral nebula as M51, the 51st non‑comet object in his catalogue, a milestone in early deep‑sky astronomy.
By Felo News Desk · Published
On Oct. 13, 1773 French astronomer Charles Messier recorded a fuzzy, comet‑like object that would later be identified as the Whirlpool Galaxy, also catalogued as M51.
What happened
Messier was compiling a list of objects that could be mistaken for comets when he noted the new entry, designating it the 51st such object. He could not see its spiral structure and therefore did not recognise it as a galaxy. The object lies about 31 million light‑years from Earth in the constellation Venatici and appears at magnitude 8.4, visible through a small telescope, especially in May, according to NASA.
What the reports add
Space.com explains that Messier’s catalogue aimed to help comet hunters avoid false alarms; by 1773 he had already listed over four dozen similar objects, beginning with the Crab Nebula (M1) in 1758. The article notes that the Whirlpool Galaxy’s striking arms are now understood to result from a close encounter with its companion NGC 5195, an interaction that may have occurred about 500 million years ago and likely spurred a burst of star formation, as stated by NASA’s Spitzer Space Telescope scientists.
What was said
Space.com quotes NASA: “This gravitational tug of war may also have triggered an increased level of star formation in M51.” The outlet also cites the Hubble Space Telescope image showing the galaxy’s long, dust‑laden arms and the more distant companion NGC 5195.
How it came about
Messier’s work built on earlier comet observations; his first non‑comet entry, the Crab Nebula (M1), was added in 1758 while studying a comet. By the time he logged M51, he had catalogued 51 objects to aid astronomers in distinguishing true comets from static nebulae. Subsequent observers, including William Parsons in 1845, recognised the whirlpool shape but interpreted it as a spiral nebula. It was not until Edwin Hubble’s extragalactic research that M51 was confirmed as a separate galaxy.
Key facts
- Charles Messier recorded the object later known as the Whirlpool Galaxy on Oct. 13 1773. (space.com)
- Messier listed it as M51, the 51st non‑comet object in his catalogue. (space.com)
- The galaxy lies about 31 million light‑years from Earth in the constellation Venatici. (space.com)
- NASA scientists attribute the galaxy’s spiral shape to a past interaction with NGC 5195. (space.com)
Sources
- [1] space.com — originally reported as “On this day in space! Oct. 13, 1773: Astronomer Charles Messier discovers the Whirlpool Galaxy before we ever knew it was a galaxy”
