@jessie My favourite off- and on nerdsniping relationship is timekeeping. Precision timekeeping. There is this half assembled diy NTP server with rubidium frequency normal, I need to finish, I like to watch curiousmarc's "clock repair" videos (cesium clocks) and recently found out that some team managed to assess Einstein's equivalency principle by spreading out several strontium atoms in a µK cold vacuum chamber, using them as clocks you can precisely manipulate along the two relevant axes.