Asteroid Discovery - 1970-2015 - 8K resolution

No need to invoke aliens. We're seeing these now because our ability to find smaller objects in the solar system has improved rapidly over the last few decades, as is evident from this animation of asteroid discoveries: [VIDEO]

> 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: [VIDEO]

Well, look at it this way: [VIDEO] [Asteroid Discovery - 1970-2015 - 8K resolution] Take your pick! And remember one doesn't need a tidy Hohman transfer. Rather the opposite in fact. The nastier the intersect angle the better. (Hopefully we don't end up on some watchlist :-P )

Not entirely, but in part! You can see the effect in this animation of asteroid discoveries over time, where the discoveries are concentrated in bursts facing directly away from Earth, or directly parallel to its orbit. [VIDEO]