From Earth’s vantage point in one of the Milky Way’s spiral arms, the structure of our galaxy is pretty difficult to reconstruct.

That’s because gauging the distance to something in space when you don’t know its intrinsic brightness is really, really hard. And there are a lot of objects in the Milky Way whose brightness is unknown to us. This means that sometimes, we can totally miss huge structures that you’d think should be right under our noses.

A new set of such enormous structures has now been unveiled at the outer regions of the Milky Way disk: massive, spinning filaments with unclear provenance. Astronomers will be conducting follow-up surveys to try and solve the mystery.