As we carefully map the stars of our Milky Way, we’re able to identify features that tell us of its history. These include local details, such as the stars that have passed through an area from which something would be able to detect Earth. And it includes far larger structures, like the trails of stars left behind by smaller galaxies that have merged with our own.
But one feature we’ve discovered has been a bit confusing: trails of stars that are too small and thin to have come from a galaxy collision. There are dozens of them that we’ve not identified a source for. Their size suggests they came from a globular cluster, but there’s no obvious mechanism for these clusters to eject stars at a rate sufficient to generate this sort of stream.
Now, a team of researchers has suggested a not-so-obvious mechanism: Over time, clusters may become dominated by black holes that eject all the stars.