https://arxiv.org/pdf/1803.01585.pdf Atomic Clocks for Geodesy https://www.sciencenews.org/article/quantum-timekeeping https://en.wikipedia.org/wiki/Physical_geodesy#Gravity_anomalies https://en.wikipedia.org/wiki/Gravimetry Gravimetric Geodesy "We're not even close to the limits of what people are imagining. By combining multiple ultra-precise orbiting clocks with quantum teleportation networks linking them for time transfer one could gravimetrically map the planet in 3D at millimeter resolutions. You’d be able to see someone digging a tunnel under the border from space. Whoever possessed it would also be able to locate every single significant concentration of dense matter." Your dense stashes of Gold lose to scattered Bitcoin paper wallets ;) https://www.nist.gov/blogs/taking-measure/keeping-time-nist https://en.wikipedia.org/wiki/2019_redefinition_of_the_SI_base_units https://www.darpa.mil/program/micro-technology-for-positioning-navigation-an... https://onlinelibrary.wiley.com/doi/full/10.1002/andp.201800364 https://www.scientificamerican.com/article/first-u-s-small-nuclear-reactor-d... Crypto miners first to adopt nextgen mini nuke plants...