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>with gold foil more ubiquitous than lead foil

Just to clarify, that doesn't necessarily mean that gold is found more commonly than lead, it's that gold foil was relatively easy to make compared to lead foil? Is that still true today?

I recall selling and using adhesive lead foil for adjusting the weight and balance of tennis racquets, for example. Most modern commercial uses of gold foil I've noticed seem to be related to artistic projects or embellishing food at fancy restaurants.

gold is so malleable that with just a hammer and a lot of determination, you can make a sheet of pure gold which is only ~ 3 atoms thick!

(when this sheet was irradiated, Rutherford's team observed that >>99% of the electrons went right through the sheet like a too large sieve. and the percentage of reflected back/passing through is the size of the nucleus vs the atom and that the atom itself is mostly empty)

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Tidal heating is not a significant source of geothermal heat on Earth, the two primary sources are radioactive decay and left over heat from planetary accretion. Tidal heating is important on other bodies, e.g., Io, but not on Earth. You are still correct in that both sources of heat on Earth (i.e., heat from radioactive decay and primordial heat) are decreasing on geologic timescales.

It is also worth noting that mitochondrial eve can change over time. Say this person had 2 daughters and at some point it just so happens that all of those descended from daughter 2 die out. Then daughter 1 now becomes mitochondrial eve, since that is now the most recent common ancestor.

Obviously our math isn't getting us precise enough to detect that single generational change. But recognizing mitochondrial eve is a concept (whoever the current most recent common female ancestor is) rather than a person (that gal named Ugh Ugh who lived in that cave over there) is helpful. It is pointing at an individual at a time, but that individual can change as human populations change and matrilineal lines die out.

I'll add since no one said this but gold does not oxidize. To get a metallic sheet so this and at this time it must be hammered thin. You can get gold so thin is transparent.

Being so thin the something made of really almost any other metal would be very oxidized.

Another difficulty is that most other metals work harden or are just much harder, for example platinum which does not oxidize well either does not forge into sheets like this easily.

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I think the other comment is probably more pertinent to what you were asking, but it's also interesting to note that geothermal heat comes from decaying radioactive isotopes and tidal heating. Both of these also reduce over time, as isotopes decay into more stable ones and orbits circularize, so these sources will also be "used up" too, but on geological time scales

So, I understand that this is a simplified example, but I’ll ask anyway. Is it know how many daughters mitochondrial Eve would have had? Everyone can trace back to her, which means not everyone can trace back to her daughters — right?

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Yes, at least in the short term and in the area immediately around (and at the depth) where heat is being extracted. Rocks are not great conductors, so in extracting heat from rocks in a geothermal power plant (usually through cycling a fluid to depth and then back up to the surface), the temperature of the rocks at the target depth in the vicinity of the plant will decrease through time basically because the process by which we extract heat is much more efficient than the process by which the rocks are reheated by conduction or movement of heated brines. This is one of the reasons individual geothermal power plants have lifespans (along with the progressive corrosion of, and precipitation of various solids in, the pipes and pumps involved in the geothermal plant, depending on the type of plant). The lifespan of a plant can be extended if less power is drawn from it (i.e., you can get a lot of power for a short time or less power for a longer time), but eventually the productivity of the plant will still decline through time (e.g., Budisulistyo et al., 2017). Similarly, there are mechanisms to try to replenish heat to slow the degradation of the resource, e.g., one proposal is coupling geothermal and solar heating where you heat fluids at the surface via solar energy and then cycle these hot fluids down to offset some of the heat extracted as part of generating geothermal power (e.g., Wendt & Mines, 2014).

In terms of long-term or large-spread geologic effects of this? Not really. Because rocks are poor conductors, the area of cooling will be relatively localized around the horizons being exploited by the plant and the area will be reheated, but on a timescale that is significantly longer than the typical few decade lifespan of an average geothermal power plant.

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It’s not so much the mating as it is staying attached prevents another male from trying to inseminate a receptive female immediately after the mating occurs. This is an evolutionary advantage to increase the chances that the primary male passes on his genetic material to another generation.

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Shielding effectiveness always increases with thickness. Thin/low weight shields are more desirable from a cost perspective.

Orbits where electron contributions dominate dose are more easily shielded which may be what you are remembering

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You're right in general, but OP's question was in reference to the last 20,000 years, focusing on a Wikipedia figure whose data were primarily collected from corals and other shallow-water biological proxies.