[Serious] Is the Past Real?

[Anomalocaris]

Not necessarily, as a meandering black hole could be snaking its way over to us with a close encounter 12 months from now.

Highly unlikely as we have not detected any gravitational anomalies or any accretion disks.

It could be a small substellar mass primordial black hole slung shot towards us due to a close encounter with a pair of closely orbiting massive objects, so that it is too small to be accreting noticeable amount of matter from interstellar medium, and traveling too fast for it have been in the vicinity of the solar system for long enough to create detectable gravitational perturbations.

We can outline the known constrains on each element of this scenario, and in principle arrive at a probability of its occurance.   although because the constraints on some element, like the number of sub stellar black holes, are very loose, the range of probability is also going to be wide.

But this is an example of unknown, but in principle knowable.