Um, what? The "time machine" of sediments is exactly analogous to the time machine of redshift. There is even the same fossils, e.g. the uncovered "relic" of the cosmic microwave background as (re)combination happens. There is even a familiar spottiness in the astronomical sediments, due to absorption from molecular clouds et cetera. Since none of the two suggested ideas are physically realizable I'm not going to bother with them. But I have one nitpick: "For example we need to gain a better understanding of the following: ... Effects of the Lake Toba supervolcanic eruptions on human migration and evolution". Since the null hypothesis is that no effect is observable, and AFAIK no effect is observable, I don't see why this item made the list. We can't add observations (such as the Lake Toba eruption) if there is no known correlation to migration and evolution.