Everyone knows about open clusters, loosely organized , amorphous collections of several dozen to several thousand stars embedded in the galactic disk. These are the families of stars that condensed out of a cloud of gas and dust. There are thousands of these objects in our galaxy; the nurseries where stars are born, and where they are continuing to be born. Our sun formed in one of these clouds, and was once a member of an open cluster. These clusters are only loosely gravitationaly bound, relatively young, and temporary. They are usually dispersed by galactic gravitational tidal forces after just a few million years, scattering their members into the disk population.

The globular cluster is a totally different creature. These are huge objects, containing hundreds of thousands to millions of stars, tightly gravitationally bound into stable spherical systems. They are very old, probably formed when the galaxy itself first formed soon after the Big Bang, over thirteen billion years ago. They circle their parent galaxies in random, elliptical orbits. The Milky Way has several hundred of them. Some galaxies have thousands.

One of these objects, NGC 2419, has been located in extragalactic space, well outside our own galaxy. It has have either been ejected from the Milky Way, or perhaps cast out of some other system and is wandering through the voids between the galaxies. Perhaps they are members of our own Milky Way and are just at the apogee of an extreme orbit around the Milky Way center. But I prefer to think of them as true extragalactic wanderers, perhaps even artifacts created by some advanced civilization long ago to escape from trouble in their own neighborhood; thousands of worlds circling thousands of stars hiding in plain sight in the emptiness.

http://cdn.sci-news.com/images/enlarge5/image_6935e-NGC-2419.jpg