Pierre Méchain discovered it in 1780 while working in the same comet-hunting world that produced Messier’s catalog. A small telescope shows little more than a faint patch, but that modest glow is the combined light of an ancient spherical population of stars packed increasingly tightly toward a common center.
Globular clusters are relics of the Milky Way’s deep past. Their stars are generally old, and the clusters orbit through the Galactic halo rather than tracing the young star-forming disk in the way open clusters do.
M72 is valuable precisely because it refuses to be flashy. The observer sees a dim unresolved glow; the physical object is an enormous gravitational community of stars at a distance that makes its light seem almost inconsequential.
Sometimes the faintest-looking entry on the calendar has the largest scale behind it.
Sources: NASA Hubble Messier Catalog, “Messier 72.”
