Why is it not valid, when related to earth? Why does it matter if there is a temporal aspect in any application of PD?

ok - comment then: I am finding it super hard to choose which answer is the suitable one (voice of Lambert: "there can be only one"). Each provides merit to be the answer in a different manner. Why can't we choose multiple answers, even if I'm only credited points for one, the people answering should be rewarded for the various dimensions they've added to the overall answer.

I think Wandy would be upset, as it's last name is McWandface