A very good article, Amelia, though it does assume the casual reader knows quite a bit about cosmology. I’d suggest that we can’t really manipulate any of the three spatial dimensions either, because moving through them isn’t the same as manipulating them. E.g. we can’t decide to “ignore” one and become 2-dimensional for a while. Perhaps a better word would be “move around in” because we can move around in 3 dimensions but we’re limited to traversing time at the speed of light; we can neither slow down nor speed up our velocity through time relative to our own reference frame. While I personally suspect that a fifth dimension may turn out to be the explanation for gravity & electromagnetic radiation, I’m still totally in the dark with regards to an adequate description of time. I can only hope to live long enough to still be around when some rich and testable hypothesis is developed!