The edge of the Solar System is a strange place, full of oddities we’ve only just begun to probe. But perhaps the oddest of all is the Oort Cloud, a vast field of icy debris extending out to 100,000 times the distance between Earth and the Sun.

We have a rough idea of the size and shape of this field, but the fine particulars elude our understanding. Now, a new computational study has revealed a surprising structure – a spiral generated by the tidal forces exerted by the Milky Way galaxy itself.

The finding, in press at The Astrophysical Journal, is currently available on preprint server arXiv.