M2 or Messier-2 is a "Globular Cluster"... a spherical collection of many stars that are gravitationally bound to each other. Presumably they appeared as globes to early astronomers.
Globular clusters are odd things. They are nearly always comprised of very old stars that have very little "metal". That means that the stars were "born" in the early universe before there was much more than Hydrogen and Helium. Large collections of stars that are gravitationally bound is what we consider to be a galaxy... and I like to think of them as mini galaxies.
Globular clusters are also unusual in where they are located with respect to the rest of stars in the galaxy. In a disk galaxy like the Milky Way they are far more often found outside the disk than normal.
I once wondered if a Globular Cluster might be a good place for many different life forms to advance on separate planets around different stars and be in contact with each other. An intelligent life form would be able to make contact with another about a nearby star (of which there are many) with far less difficulty than us. Apparently the light from the other stars would not be too hot/bright, but a few supernovae would put an end to all of those life forms. Most important is the simple fact that such old stars would have no rocky planets because there would be virtually no carbon, no iron, no oxygen...
M2 seems typical for a Globular Cluster. It is a huge collection of 150,000 low-metallicity old stars. It is estimated that the stars are 13 billion years old. Consider that the universe is less than 14 billion years old... this cluster formed not long after the universe itself came into being (via the "big bang" or however that "happened").
It is big and bright - otherwise we'd never see it because it is very far away. The center of our galaxy is roughly 25,000 light years away, and M2 is 40,000 to 50,000 light years away. Consider that the nearby Orion Nebula is 1,300 light years away. All these objects are part of the Milky Way galaxy.
M2 is not part of the galactic disk, but rather is part of the "halo" population, orbiting the galactic center quite differently than does our star, the Sun. Finally, to top it all off, recent research suggests that M2 is part of another small galaxy that merged with the Milky Way many billions of years ago. It has many characteristics in common with a set of stars known as the "Gaia Sausage" - which in turn are behaving very differently from normal Milky Way stars.
So this faint cluster of stars is quite the galactic neighbor. It is very much older, a closed community of stars that likely have no rocky planets and which turns out to be an immigrant population if we go back far enough.
The image shown here was taken from the Lac Teeples Deep Sky Observatory on October 7, 2021. Only 8 minutes of data were used to form this image.
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