3 ms·

This comment made me curious. Apparently, TAI specifically defines the second (in terms of cesium transitions) at sea level (where gravitational potential is e

• Xorathena 2y ago
  ...and one level of language-precision further, these articles get into how "sea level" differs from "where gravitational potential is equal": https://en.wikipedia.org/wiki/Ocean_surface_topography https://en.wikipedia.org/wiki/Ocean_surface_topography https://en.wikipedia.org/wiki/Geoid https://en.wikipedia.org/wiki/Geoid