Messier 2 or M2 (also designated NGC 7089) is a globular cluster in the constellation Aquarius, five degrees north of the star Beta Aquarii.

M2 was discovered by the French astronomer Jean-Dominique Maraldi in 1746[9] while observing a comet with Jacques Cassini.

It is 12.5 billion years old and one of the older globular clusters associated with the Milky Way galaxy.

[8] M2 is part of the Gaia Sausage, the hypothesized remains of a merged dwarf galaxy.

[12] Data from Gaia has led to the discovery of an extended tidal stellar stream, about 45 degrees long and 300 light-years (100 pc) wide, that is likely associated with M2.

While it satisfies the metallicity and RRab Lyrae pulsation period conditions, it actually has an age of 12.5 Gyr, well below the cutoff age of 13 Gyr normal for a Oosterhoff type II cluster.