[Zimahl]

It is 'magic' but a really interesting concept. It's essentially a self-replicating terraforming device. An ancient civilization sends out probes with the molecule - in this case a small planetoid - that will hopefully crash into a planet with biological material and then collect and convert said material into a ring that connects to an interstellar network. The problem is that the one in The Expanse got caught up in Jovian system, like gets done with a lot of interstellar objects.

[thereddaikon]

It's a variation on the Von Neumann probe. A self replicating spacecraft. Instead of being for exploration or production of a specific widget its purpose is building ftl gates as part of a presumably galactic network.