Galaxy discoverers I: The fascinating tale of Charles Messier

May 25, 2025

There are more galaxies in the universe than there are stars in our Milky Way. Astronomers estimate that there are around two trillion galaxies out there, each with billions of stars and possibility of a planetary system just like ours, around each of them. But do you know the fascinating stories of people who discovered that some of these beacons of light in our skies were galaxies far far away from our own?

Born in the year 1730 in France, Charles Messier was fascinated by astronomy since early childhood. His passion and hard work, took him to the court of King Louis XV of france. But back in the day people were superstitious and feared unusual astronomical events such as eclipses (well, in some places around the globe people still do). They believed that some day an object from the heavens can hit their kingdom, and destroy their lives.

In order to relieve his people from the fear of the unknown, the king asked Messier , the court astronomer and polymath, to prepare a list of all the possible comets which can collide with Earth and cause destruction. In an attempt to do so, Messier realised that there were many fuzzy looking things in the sky which looked like comets but didn’t seem to move much. This annoyed him very much, and in his frustration, he decided to prepare a list of all such fuzzy clouds, to help him and other comet hunters in their endeavours. His final list is what we now call the Messier catalogue: the first ever documented list of astronomical objects which, amongst others included galaxies, even though, its creator was clueless of his achievements.

The Messier catalogue contains 110 objects, with each object name beginning with a letter M followed by a serial number. These objects are known by their messier names to date. The Messier catalogue is particularly admired by amateur astronomers because not only is his list a good mix of galactic and extragalactic objects, but most of them are also easily observable with a good pair of binoculars or a small telescope. What Messier thought all looked like nebulae through his small telescope, are actually a collection of objects from single stars such as planetary nebulae and SNe, a collection of tens of thousands of stars in a star cluster, to millions of stars in galaxies.

But to Messier and his contemporaries, all of these objects looked similar, because the apparent size and brightness of bigger objects as observed by them were similar. In other words, if a galaxy is 10 times as big and luminous as a star cluster, but also 10 times farther away, then through a small telescope they will both appear faint hazy clouds of light. Little did Messier knew that he had created history by documenting observations of not 1 or 2 but several nebulae much farther away than our Milkyway. Nebulae, that we now call galaxies.

Know more about him, and other galaxy discoverers in my video here.