What Are Supernova Remains?

We don't know if Earth is typical or if it's weird and rare in the universe. We can look for supernovas that have happened that we might have missed, because we can see supernova remnants. There are galaxies with lots of dark matter and galaxies who have very little dark matter. And there are galaxies that are still making stars and galaxies that will no longer be producing stars. These are the kind of questions we get to ask as we try to figure out whether our context is normal or really, really weird.