Messier 102 (M102) – The Spindle Galaxy

Messier 102 is a lenticular galaxy in the Draco constellation seen edge-on from our position. It’s approximately 45 million light years away from us and is roughly 65,000 light years in breadth (compared to about 100,000 light years for our own Milky Way galaxy). It hosts around 100 billion stars (compared to the Milky Way’s 400 billion).

Pierre Méchain ostensibly discovered M102 in 1781 and it made the final version of Messier’s catalogue published later that year. But Messier didn’t list its coordinates, which created some confusion right out of the gate. In 1783 Méchain retracted his discovery saying that he had actually observed Messier 101. Whether M101 and M102 are supposed to be the same galaxy is a controversy that continues to this day. But most astronomers agree that M102 is what you see in this image—a galaxy later added to the New General Catalogue as NGC 5866. NASA apparently agrees. And an examination of Méchain and Messier’s notes supports that conclusion.

Lenticular galaxies are similar to spiral galaxies in that they have a central bulge and a disk, but they don’t have spiral arms. Like elliptical galaxies, they tend to have older stellar populations and are largely bereft of star-forming.