[js1138]

Any branch of science which proposes to explain the unobserved past is metaphysical.

And Newton's astronomomy, which is routinely used to determine the positions of the planets in the past, is metaphysical?

[GourmetDan]

That's correct.

Past planetary positions that are not observed but based on calculations extrapolated from current observation are metaphysical.

You are starting to understand.

Good.