[wcoenen]

> What happens next is entirely out of human hands, unless we can realize that event.

We would not have been able to detect this object two decades ago. So the "event" is that our observation capabilities have grown past some threshold, not that anything has changed in our solar system. Whether rocks or alien probes, these types of objects must always have been passing through our solar system with some regularity. We'll get a a chance to study others soon enough.

Edit: this video by Scott Manley helps to get a sense of how our ability to detect asteroids has grown over time: https://youtu.be/BKKg4lZ_o-Y